From 385ec6ad2dab67ed9d059bf82e4c080483e80eba Mon Sep 17 00:00:00 2001 From: dignifiedquire Date: Wed, 29 Apr 2026 07:06:00 +0000 Subject: [PATCH] deploy: 408a65414df81a9c995f1098b0de585f3dbdaad1 --- pr/616/docs/help.html | 2 +- pr/616/docs/noq/enum.ClosePathError.html | 6 +- pr/616/docs/noq/enum.ConnectionError.html | 6 +- pr/616/docs/noq/enum.PathError.html | 6 +- pr/616/docs/noq/enum.PathEvent.html | 6 +- pr/616/docs/noq/enum.PathStatus.html | 6 +- pr/616/docs/noq/enum.SetPathStatusError.html | 6 +- pr/616/docs/noq/struct.ClosedPath.html | 6 +- pr/616/docs/noq/trait.NetworkChangeHint.html | 4 +- .../docs/noq_proto/enum.ClosePathError.html | 6 +- .../docs/noq_proto/enum.ConnectionError.html | 6 +- pr/616/docs/noq_proto/enum.Event.html | 4 +- .../noq_proto/enum.PathAbandonReason.html | 6 +- pr/616/docs/noq_proto/enum.PathError.html | 6 +- pr/616/docs/noq_proto/enum.PathEvent.html | 6 +- pr/616/docs/noq_proto/enum.PathStatus.html | 6 +- .../noq_proto/enum.SetPathStatusError.html | 6 +- .../n0_nat_traversal/enum.Error.html | 4 +- .../n0_nat_traversal/enum.Event.html | 4 +- .../noq_proto/n0_nat_traversal/index.html | 2 +- pr/616/docs/noq_proto/struct.ClosedPath.html | 6 +- pr/616/docs/noq_proto/struct.Connection.html | 70 +- .../struct.MultipathNotNegotiated.html | 4 +- .../docs/noq_proto/struct.RttEstimator.html | 10 +- .../docs/noq_proto/struct.TransportError.html | 2 +- .../noq_proto/trait.NetworkChangeHint.html | 4 +- pr/616/docs/settings.html | 2 +- .../docs/src/noq_proto/connection/mod.rs.html | 11306 ++++++++-------- .../src/noq_proto/connection/paths.rs.html | 1217 +- .../src/noq_proto/connection/spaces.rs.html | 3105 ++--- pr/616/docs/src/noq_proto/frame.rs.html | 993 +- .../src/noq_proto/n0_nat_traversal.rs.html | 1499 +- 32 files changed, 9183 insertions(+), 9139 deletions(-) diff --git a/pr/616/docs/help.html b/pr/616/docs/help.html index cda0c7f93..09d0ca8e7 100644 --- a/pr/616/docs/help.html +++ b/pr/616/docs/help.html @@ -1 +1 @@ -Help

All

Rustdoc help

Back
\ No newline at end of file +Help

All

Rustdoc help

Back
\ No newline at end of file diff --git a/pr/616/docs/noq/enum.ClosePathError.html b/pr/616/docs/noq/enum.ClosePathError.html index e4a4a3fd5..5ea7eee51 100644 --- a/pr/616/docs/noq/enum.ClosePathError.html +++ b/pr/616/docs/noq/enum.ClosePathError.html @@ -1,4 +1,4 @@ -ClosePathError in noq - Rust

ClosePathError

noq

Enum ClosePathError 

Source 
pub enum ClosePathError {
+ClosePathError in noq - Rust
ClosePathError
noq
Enum ClosePathError 
Source 
pub enum ClosePathError {
     MultipathNotNegotiated,
     ClosedPath,
     LastOpenPath,
@@ -7,8 +7,8 @@
 
§
ClosedPath
The path is already closed or was never opened

 
§
LastOpenPath
Cannot close the last remaining open path via the local API.

 
Use Connection::close to end the connection instead.

-

Trait Implementations§

Source§

impl Clone for ClosePathError

Source§

fn clone(&self) -> ClosePathError

Returns a duplicate of the value. Read more
1.0.0 · Source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
Source§

impl Debug for ClosePathError

Source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
Source§

impl Display for ClosePathError

Source§

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
Source§

impl Error for ClosePathError

1.30.0 · Source§

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
1.0.0 · Source§

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§

impl PartialEq for ClosePathError

Source§

fn eq(&self, other: &ClosePathError) -> bool

Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, -and should not be overridden without very good reason.
Source§

impl Eq for ClosePathError

Source§

impl StructuralPartialEq for ClosePathError

Auto Trait Implementations§

Blanket Implementations§

Source§

impl<T> Any for T
where +

Trait Implementations§

Source§

impl Clone for ClosePathError

Source§

fn clone(&self) -> ClosePathError

Returns a duplicate of the value. Read more
1.0.0 · Source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
Source§

impl Debug for ClosePathError

Source§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
Source§

impl Display for ClosePathError

Source§

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
Source§

impl Error for ClosePathError

1.30.0 · Source§

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§

fn description(&self) -> &str

👎Deprecated since 1.42.0: use the Display impl or to_string()
Read more
1.0.0 · Source§

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§

impl PartialEq for ClosePathError

Source§

fn eq(&self, other: &ClosePathError) -> bool

Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, +and should not be overridden without very good reason.
Source§

impl Eq for ClosePathError

Source§

impl StructuralPartialEq for ClosePathError

Auto Trait Implementations§

Blanket Implementations§

Source§

impl<T> Any for T
where T: 'static + ?Sized,

Source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
Source§

impl<T> Borrow<T> for T
where T: ?Sized,

Source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
Source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

Source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
Source§

impl<T> CloneToUninit for T
where diff --git a/pr/616/docs/noq/enum.ConnectionError.html b/pr/616/docs/noq/enum.ConnectionError.html index 20de8e1ae..9789e7ada 100644 --- a/pr/616/docs/noq/enum.ConnectionError.html +++ b/pr/616/docs/noq/enum.ConnectionError.html @@ -1,4 +1,4 @@ -ConnectionError in noq - Rust

ConnectionError

noq

Enum ConnectionError 

Source 
pub enum ConnectionError {
+ConnectionError in noq - Rust
ConnectionError
noq
Enum ConnectionError 
Source 
pub enum ConnectionError {
     VersionMismatch,
     TransportError(Error),
     ConnectionClosed(ConnectionClose),
@@ -20,8 +20,8 @@ and §
LocallyClosed
The local application closed the connection

 
§
CidsExhausted
The connection could not be created because not enough of the CID space is available

 
Try using longer connection IDs.

-
Trait Implementations§
Source§
impl Clone for ConnectionError
Source§
fn clone(&self) -> ConnectionError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ConnectionError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Display for ConnectionError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for ConnectionError
Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl From<Close> for ConnectionError
Source§
fn from(x: Close) -> ConnectionError
Converts to this type from the input type.
Source§
impl From<CloseReason> for ConnectionError
Source§
fn from(value: CloseReason) -> ConnectionError
Converts to this type from the input type.
Source§
impl From<ConnectionError> for ReadError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for ResetError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for SendDatagramError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for StoppedError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for WriteError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for ConnectionError
Source§
fn from(source: Error) -> ConnectionError
Converts to this type from the input type.
Source§
impl PartialEq for ConnectionError
Source§
fn eq(&self, other: &ConnectionError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for ConnectionError
Source§
impl StructuralPartialEq for ConnectionError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for ConnectionError
Source§
fn clone(&self) -> ConnectionError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ConnectionError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Display for ConnectionError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for ConnectionError
Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl From<Close> for ConnectionError
Source§
fn from(x: Close) -> ConnectionError
Converts to this type from the input type.
Source§
impl From<CloseReason> for ConnectionError
Source§
fn from(value: CloseReason) -> ConnectionError
Converts to this type from the input type.
Source§
impl From<ConnectionError> for ReadError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for ResetError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for SendDatagramError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for StoppedError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<ConnectionError> for WriteError
Source§
fn from(source: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for ConnectionError
Source§
fn from(source: Error) -> ConnectionError
Converts to this type from the input type.
Source§
impl PartialEq for ConnectionError
Source§
fn eq(&self, other: &ConnectionError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for ConnectionError
Source§
impl StructuralPartialEq for ConnectionError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq/enum.PathError.html b/pr/616/docs/noq/enum.PathError.html
index b48c22d4a..db54abc82 100644
--- a/pr/616/docs/noq/enum.PathError.html
+++ b/pr/616/docs/noq/enum.PathError.html
@@ -1,4 +1,4 @@
-PathError in noq - Rust
PathError
noq
Enum PathError 
Source 
pub enum PathError {
+PathError in noq - Rust
PathError
noq
Enum PathError 
Source 
pub enum PathError {
     MultipathNotNegotiated,
     ServerSideNotAllowed,
     MaxPathIdReached,
@@ -12,8 +12,8 @@
 
§
RemoteCidsExhausted
No remote CIDs available to open a new path

 
§
ValidationFailed
Path could not be validated and will be abandoned

 
§
InvalidRemoteAddress(SocketAddr)
The remote address for the path is not supported by the endpoint

-
Trait Implementations§
Source§
impl Clone for PathError
Source§
fn clone(&self) -> PathError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Display for PathError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for PathError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for PathError
Source§
fn eq(&self, other: &PathError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Copy for PathError
Source§
impl Eq for PathError
Source§
impl StructuralPartialEq for PathError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathError
Source§
fn clone(&self) -> PathError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Display for PathError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for PathError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for PathError
Source§
fn eq(&self, other: &PathError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Copy for PathError
Source§
impl Eq for PathError
Source§
impl StructuralPartialEq for PathError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq/enum.PathEvent.html b/pr/616/docs/noq/enum.PathEvent.html
index da4b6dad6..d3226b00c 100644
--- a/pr/616/docs/noq/enum.PathEvent.html
+++ b/pr/616/docs/noq/enum.PathEvent.html
@@ -1,4 +1,4 @@
-PathEvent in noq - Rust
PathEvent
noq
Enum PathEvent 
Source 
pub enum PathEvent {
+PathEvent in noq - Rust
PathEvent
noq
Enum PathEvent 
Source 
pub enum PathEvent {
     Opened {
         id: PathId,
     },
@@ -39,8 +39,8 @@ changes the status.

 
Fields
§id: PathId
Path over which the observed address was reported, PathId::ZERO when multipath is
 not negotiated

 
§addr: SocketAddr
The address observed by the remote over this path

-
Trait Implementations§
Source§
impl Clone for PathEvent
Source§
fn clone(&self) -> PathEvent
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathEvent
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl PartialEq for PathEvent
Source§
fn eq(&self, other: &PathEvent) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for PathEvent
Source§
impl StructuralPartialEq for PathEvent
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathEvent
Source§
fn clone(&self) -> PathEvent
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathEvent
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl PartialEq for PathEvent
Source§
fn eq(&self, other: &PathEvent) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for PathEvent
Source§
impl StructuralPartialEq for PathEvent
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq/enum.PathStatus.html b/pr/616/docs/noq/enum.PathStatus.html
index 4422c371b..f6c4f6825 100644
--- a/pr/616/docs/noq/enum.PathStatus.html
+++ b/pr/616/docs/noq/enum.PathStatus.html
@@ -1,4 +1,4 @@
-PathStatus in noq - Rust
PathStatus
noq
Enum PathStatus 
Source 
pub enum PathStatus {
+PathStatus in noq - Rust
PathStatus
noq
Enum PathStatus 
Source 
pub enum PathStatus {
     Available,
     Backup,
 }
Expand description
The QUIC-MULTIPATH path status

@@ -10,8 +10,8 @@ capacity.

 
§
Backup
Paths marked as backup will only be used if there are no available paths

 
If the max_idle_timeout is specified the path will be kept alive so that it does not
 expire.

-
Trait Implementations§
Source§
impl Clone for PathStatus
Source§
fn clone(&self) -> PathStatus
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathStatus
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Default for PathStatus
Source§
fn default() -> PathStatus
Returns the “default value” for a type. Read more
Source§
impl PartialEq for PathStatus
Source§
fn eq(&self, other: &PathStatus) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Copy for PathStatus
Source§
impl Eq for PathStatus
Source§
impl StructuralPartialEq for PathStatus
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathStatus
Source§
fn clone(&self) -> PathStatus
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathStatus
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Default for PathStatus
Source§
fn default() -> PathStatus
Returns the “default value” for a type. Read more
Source§
impl PartialEq for PathStatus
Source§
fn eq(&self, other: &PathStatus) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Copy for PathStatus
Source§
impl Eq for PathStatus
Source§
impl StructuralPartialEq for PathStatus
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq/enum.SetPathStatusError.html b/pr/616/docs/noq/enum.SetPathStatusError.html
index 2a9557440..4d1b5d584 100644
--- a/pr/616/docs/noq/enum.SetPathStatusError.html
+++ b/pr/616/docs/noq/enum.SetPathStatusError.html
@@ -1,11 +1,11 @@
-SetPathStatusError in noq - Rust
SetPathStatusError
noq
Enum SetPathStatusError 
Source 
pub enum SetPathStatusError {
+SetPathStatusError in noq - Rust
SetPathStatusError
noq
Enum SetPathStatusError 
Source 
pub enum SetPathStatusError {
     ClosedPath,
     MultipathNotNegotiated,
 }
Expand description
Error from setting path status

 
Variants§
§
ClosedPath
Error indicating that a path has not been opened or has already been abandoned

 
§
MultipathNotNegotiated
Error indicating that this operation requires multipath to be negotiated whereas it hasn’t been

-
Trait Implementations§
Source§
impl Clone for SetPathStatusError
Source§
fn clone(&self) -> SetPathStatusError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for SetPathStatusError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Display for SetPathStatusError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for SetPathStatusError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for SetPathStatusError
Source§
fn eq(&self, other: &SetPathStatusError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for SetPathStatusError
Source§
impl StructuralPartialEq for SetPathStatusError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for SetPathStatusError
Source§
fn clone(&self) -> SetPathStatusError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for SetPathStatusError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Display for SetPathStatusError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for SetPathStatusError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for SetPathStatusError
Source§
fn eq(&self, other: &SetPathStatusError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for SetPathStatusError
Source§
impl StructuralPartialEq for SetPathStatusError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq/struct.ClosedPath.html b/pr/616/docs/noq/struct.ClosedPath.html
index 38e0c7a7a..245f45d51 100644
--- a/pr/616/docs/noq/struct.ClosedPath.html
+++ b/pr/616/docs/noq/struct.ClosedPath.html
@@ -1,6 +1,6 @@
-ClosedPath in noq - Rust
ClosedPath
noq
Struct ClosedPath 
Source 
pub struct ClosedPath { /* private fields */ }
Expand description
Error indicating that a path has not been opened or has already been abandoned

-
Trait Implementations§
Source§
impl Clone for ClosedPath
Source§
fn clone(&self) -> ClosedPath
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ClosedPath
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Default for ClosedPath
Source§
fn default() -> ClosedPath
Returns the “default value” for a type. Read more
Source§
impl Display for ClosedPath
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for ClosedPath
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for ClosedPath
Source§
fn eq(&self, other: &ClosedPath) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for ClosedPath
Source§
impl StructuralPartialEq for ClosedPath
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+ClosedPath in noq - Rust
ClosedPath
noq
Struct ClosedPath 
Source 
pub struct ClosedPath { /* private fields */ }
Expand description
Error indicating that a path has not been opened or has already been abandoned

+
Trait Implementations§
Source§
impl Clone for ClosedPath
Source§
fn clone(&self) -> ClosedPath
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ClosedPath
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Default for ClosedPath
Source§
fn default() -> ClosedPath
Returns the “default value” for a type. Read more
Source§
impl Display for ClosedPath
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
Source§
impl Error for ClosedPath
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for ClosedPath
Source§
fn eq(&self, other: &ClosedPath) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for ClosedPath
Source§
impl StructuralPartialEq for ClosedPath
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq/trait.NetworkChangeHint.html b/pr/616/docs/noq/trait.NetworkChangeHint.html
index 50fe8c0f7..d88774e37 100644
--- a/pr/616/docs/noq/trait.NetworkChangeHint.html
+++ b/pr/616/docs/noq/trait.NetworkChangeHint.html
@@ -1,4 +1,4 @@
-NetworkChangeHint in noq - Rust
NetworkChangeHint
noq
Trait NetworkChangeHint 
Source 
pub trait NetworkChangeHint: Debug + 'static {
+NetworkChangeHint in noq - Rust
NetworkChangeHint
noq
Trait NetworkChangeHint 
Source 
pub trait NetworkChangeHint: Debug + 'static {
     // Required method
     fn is_path_recoverable(
         &self,
@@ -6,7 +6,7 @@
         network_path: FourTuple,
     ) -> bool;
 }
Expand description
Hints when the caller identifies a network change.

-
Required Methods§
Source
fn is_path_recoverable(&self, path_id: PathId, network_path: FourTuple) -> bool
Inform the connection if a path may recover after a network change.

+
Required Methods§
Source
fn is_path_recoverable(&self, path_id: PathId, network_path: FourTuple) -> bool
Inform the connection if a path may recover after a network change.

 
After network changes, paths may not be recoverable. In this case, waiting for the path to
 become idle may take longer than what is desirable. If Self::is_path_recoverable
 returns false, a multipath-enabled, client-side connection will establish a new path to
diff --git a/pr/616/docs/noq_proto/enum.ClosePathError.html b/pr/616/docs/noq_proto/enum.ClosePathError.html
index b74b76bce..f1519c06b 100644
--- a/pr/616/docs/noq_proto/enum.ClosePathError.html
+++ b/pr/616/docs/noq_proto/enum.ClosePathError.html
@@ -1,4 +1,4 @@
-ClosePathError in noq_proto - Rust
ClosePathError
noq_proto
Enum ClosePathError 
Source 
pub enum ClosePathError {
+ClosePathError in noq_proto - Rust
ClosePathError
noq_proto
Enum ClosePathError 
Source 
pub enum ClosePathError {
     MultipathNotNegotiated,
     ClosedPath,
     LastOpenPath,
@@ -7,8 +7,8 @@
 
§
ClosedPath
The path is already closed or was never opened

 
§
LastOpenPath
Cannot close the last remaining open path via the local API.

 
Use Connection::close to end the connection instead.

-
Trait Implementations§
Source§
impl Clone for ClosePathError
Source§
fn clone(&self) -> ClosePathError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ClosePathError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for ClosePathError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for ClosePathError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for ClosePathError
Source§
fn eq(&self, other: &ClosePathError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for ClosePathError
Source§
impl StructuralPartialEq for ClosePathError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for ClosePathError
Source§
fn clone(&self) -> ClosePathError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ClosePathError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for ClosePathError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for ClosePathError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for ClosePathError
Source§
fn eq(&self, other: &ClosePathError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for ClosePathError
Source§
impl StructuralPartialEq for ClosePathError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/enum.ConnectionError.html b/pr/616/docs/noq_proto/enum.ConnectionError.html
index eef962f41..9186e9aaa 100644
--- a/pr/616/docs/noq_proto/enum.ConnectionError.html
+++ b/pr/616/docs/noq_proto/enum.ConnectionError.html
@@ -1,4 +1,4 @@
-ConnectionError in noq_proto - Rust
ConnectionError
noq_proto
Enum ConnectionError 
Source 
pub enum ConnectionError {
+ConnectionError in noq_proto - Rust
ConnectionError
noq_proto
Enum ConnectionError 
Source 
pub enum ConnectionError {
     VersionMismatch,
     TransportError(TransportError),
     ConnectionClosed(ConnectionClose),
@@ -20,8 +20,8 @@ and §
LocallyClosed
The local application closed the connection

 
§
CidsExhausted
The connection could not be created because not enough of the CID space is available

 
Try using longer connection IDs.

-
Trait Implementations§
Source§
impl Clone for ConnectionError
Source§
fn clone(&self) -> ConnectionError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ConnectionError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for ConnectionError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for ConnectionError
Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl From<ConnectionError> for Error
Source§
fn from(x: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for ConnectionError
Source§
fn from(source: TransportError) -> Self
Converts to this type from the input type.
Source§
impl PartialEq for ConnectionError
Source§
fn eq(&self, other: &ConnectionError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for ConnectionError
Source§
impl StructuralPartialEq for ConnectionError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for ConnectionError
Source§
fn clone(&self) -> ConnectionError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ConnectionError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for ConnectionError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for ConnectionError
Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl From<ConnectionError> for Error
Source§
fn from(x: ConnectionError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for ConnectionError
Source§
fn from(source: TransportError) -> Self
Converts to this type from the input type.
Source§
impl PartialEq for ConnectionError
Source§
fn eq(&self, other: &ConnectionError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for ConnectionError
Source§
impl StructuralPartialEq for ConnectionError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/enum.Event.html b/pr/616/docs/noq_proto/enum.Event.html
index e386f61fe..c952732cb 100644
--- a/pr/616/docs/noq_proto/enum.Event.html
+++ b/pr/616/docs/noq_proto/enum.Event.html
@@ -1,4 +1,4 @@
-Event in noq_proto - Rust
Event
noq_proto
Enum Event 
Source 
pub enum Event {
+Event in noq_proto - Rust
Event
noq_proto
Enum Event 
Source 
pub enum Event {
     HandshakeDataReady,
     Connected,
     HandshakeConfirmed,
@@ -25,7 +25,7 @@ fail with §
DatagramsUnblocked
One or more application datagrams have been sent after blocking

 
§
Path(PathEvent)
(Multi)Path events

 
§
NatTraversal(Event)
n0’s nat traversal events

-
Trait Implementations§
Source§
impl Debug for Event
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl From<PathEvent> for Event
Source§
fn from(source: PathEvent) -> Self
Converts to this type from the input type.
Auto Trait Implementations§
§
impl !Freeze for Event
§
impl !RefUnwindSafe for Event
§
impl Send for Event
§
impl Sync for Event
§
impl Unpin for Event
§
impl !UnwindSafe for Event
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Debug for Event
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl From<PathEvent> for Event
Source§
fn from(source: PathEvent) -> Self
Converts to this type from the input type.
Auto Trait Implementations§
§
impl !Freeze for Event
§
impl !RefUnwindSafe for Event
§
impl Send for Event
§
impl Sync for Event
§
impl Unpin for Event
§
impl !UnwindSafe for Event
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> From<T> for T
Source§
fn from(t: T) -> T
Returns the argument unchanged.

diff --git a/pr/616/docs/noq_proto/enum.PathAbandonReason.html b/pr/616/docs/noq_proto/enum.PathAbandonReason.html
index e54f8f350..be6112030 100644
--- a/pr/616/docs/noq_proto/enum.PathAbandonReason.html
+++ b/pr/616/docs/noq_proto/enum.PathAbandonReason.html
@@ -1,4 +1,4 @@
-PathAbandonReason in noq_proto - Rust
PathAbandonReason
noq_proto
Enum PathAbandonReason 
Source 
pub enum PathAbandonReason {
+PathAbandonReason in noq_proto - Rust
PathAbandonReason
noq_proto
Enum PathAbandonReason 
Source 
pub enum PathAbandonReason {
     ApplicationClosed {
         error_code: VarInt,
     },
@@ -18,8 +18,8 @@
 
§
NatTraversalRoundEnded
The path was opened in a NAT traversal round which was terminated.

 
§
RemoteAbandoned
The remote closed the path.

 
Fields
§error_code: VarInt
The error that was sent with the abandon frame.

-
Trait Implementations§
Source§
impl Clone for PathAbandonReason
Source§
fn clone(&self) -> PathAbandonReason
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathAbandonReason
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl PartialEq for PathAbandonReason
Source§
fn eq(&self, other: &PathAbandonReason) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for PathAbandonReason
Source§
impl StructuralPartialEq for PathAbandonReason
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathAbandonReason
Source§
fn clone(&self) -> PathAbandonReason
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathAbandonReason
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl PartialEq for PathAbandonReason
Source§
fn eq(&self, other: &PathAbandonReason) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for PathAbandonReason
Source§
impl StructuralPartialEq for PathAbandonReason
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/enum.PathError.html b/pr/616/docs/noq_proto/enum.PathError.html
index e2925ec10..f852d35f3 100644
--- a/pr/616/docs/noq_proto/enum.PathError.html
+++ b/pr/616/docs/noq_proto/enum.PathError.html
@@ -1,4 +1,4 @@
-PathError in noq_proto - Rust
PathError
noq_proto
Enum PathError 
Source 
pub enum PathError {
+PathError in noq_proto - Rust
PathError
noq_proto
Enum PathError 
Source 
pub enum PathError {
     MultipathNotNegotiated,
     ServerSideNotAllowed,
     MaxPathIdReached,
@@ -12,8 +12,8 @@
 
§
RemoteCidsExhausted
No remote CIDs available to open a new path

 
§
ValidationFailed
Path could not be validated and will be abandoned

 
§
InvalidRemoteAddress(SocketAddr)
The remote address for the path is not supported by the endpoint

-
Trait Implementations§
Source§
impl Clone for PathError
Source§
fn clone(&self) -> PathError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for PathError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for PathError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for PathError
Source§
fn eq(&self, other: &PathError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Copy for PathError
Source§
impl Eq for PathError
Source§
impl StructuralPartialEq for PathError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathError
Source§
fn clone(&self) -> PathError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for PathError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for PathError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for PathError
Source§
fn eq(&self, other: &PathError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Copy for PathError
Source§
impl Eq for PathError
Source§
impl StructuralPartialEq for PathError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/enum.PathEvent.html b/pr/616/docs/noq_proto/enum.PathEvent.html
index 5f84d36cc..87927cc8a 100644
--- a/pr/616/docs/noq_proto/enum.PathEvent.html
+++ b/pr/616/docs/noq_proto/enum.PathEvent.html
@@ -1,4 +1,4 @@
-PathEvent in noq_proto - Rust
PathEvent
noq_proto
Enum PathEvent 
Source 
pub enum PathEvent {
+PathEvent in noq_proto - Rust
PathEvent
noq_proto
Enum PathEvent 
Source 
pub enum PathEvent {
     Opened {
         id: PathId,
     },
@@ -39,8 +39,8 @@ changes the status.

 
Fields
§id: PathId
Path over which the observed address was reported, PathId::ZERO when multipath is
 not negotiated

 
§addr: SocketAddr
The address observed by the remote over this path

-
Trait Implementations§
Source§
impl Clone for PathEvent
Source§
fn clone(&self) -> PathEvent
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathEvent
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl From<PathEvent> for Event
Source§
fn from(source: PathEvent) -> Self
Converts to this type from the input type.
Source§
impl PartialEq for PathEvent
Source§
fn eq(&self, other: &PathEvent) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for PathEvent
Source§
impl StructuralPartialEq for PathEvent
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathEvent
Source§
fn clone(&self) -> PathEvent
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathEvent
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl From<PathEvent> for Event
Source§
fn from(source: PathEvent) -> Self
Converts to this type from the input type.
Source§
impl PartialEq for PathEvent
Source§
fn eq(&self, other: &PathEvent) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for PathEvent
Source§
impl StructuralPartialEq for PathEvent
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/enum.PathStatus.html b/pr/616/docs/noq_proto/enum.PathStatus.html
index 7c6f1e7a2..2fcac19f9 100644
--- a/pr/616/docs/noq_proto/enum.PathStatus.html
+++ b/pr/616/docs/noq_proto/enum.PathStatus.html
@@ -1,4 +1,4 @@
-PathStatus in noq_proto - Rust
PathStatus
noq_proto
Enum PathStatus 
Source 
pub enum PathStatus {
+PathStatus in noq_proto - Rust
PathStatus
noq_proto
Enum PathStatus 
Source 
pub enum PathStatus {
     Available,
     Backup,
 }
Expand description
The QUIC-MULTIPATH path status

@@ -10,8 +10,8 @@ capacity.

 
§
Backup
Paths marked as backup will only be used if there are no available paths

 
If the max_idle_timeout is specified the path will be kept alive so that it does not
 expire.

-
Trait Implementations§
Source§
impl Clone for PathStatus
Source§
fn clone(&self) -> PathStatus
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathStatus
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Default for PathStatus
Source§
fn default() -> PathStatus
Returns the “default value” for a type. Read more
Source§
impl PartialEq for PathStatus
Source§
fn eq(&self, other: &PathStatus) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Copy for PathStatus
Source§
impl Eq for PathStatus
Source§
impl StructuralPartialEq for PathStatus
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for PathStatus
Source§
fn clone(&self) -> PathStatus
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for PathStatus
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Default for PathStatus
Source§
fn default() -> PathStatus
Returns the “default value” for a type. Read more
Source§
impl PartialEq for PathStatus
Source§
fn eq(&self, other: &PathStatus) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Copy for PathStatus
Source§
impl Eq for PathStatus
Source§
impl StructuralPartialEq for PathStatus
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/enum.SetPathStatusError.html b/pr/616/docs/noq_proto/enum.SetPathStatusError.html
index 47648ab96..c96ec8096 100644
--- a/pr/616/docs/noq_proto/enum.SetPathStatusError.html
+++ b/pr/616/docs/noq_proto/enum.SetPathStatusError.html
@@ -1,11 +1,11 @@
-SetPathStatusError in noq_proto - Rust
SetPathStatusError
noq_proto
Enum SetPathStatusError 
Source 
pub enum SetPathStatusError {
+SetPathStatusError in noq_proto - Rust
SetPathStatusError
noq_proto
Enum SetPathStatusError 
Source 
pub enum SetPathStatusError {
     ClosedPath,
     MultipathNotNegotiated,
 }
Expand description
Error from setting path status

 
Variants§
§
ClosedPath
Error indicating that a path has not been opened or has already been abandoned

 
§
MultipathNotNegotiated
Error indicating that this operation requires multipath to be negotiated whereas it hasn’t been

-
Trait Implementations§
Source§
impl Clone for SetPathStatusError
Source§
fn clone(&self) -> SetPathStatusError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for SetPathStatusError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for SetPathStatusError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for SetPathStatusError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for SetPathStatusError
Source§
fn eq(&self, other: &SetPathStatusError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for SetPathStatusError
Source§
impl StructuralPartialEq for SetPathStatusError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for SetPathStatusError
Source§
fn clone(&self) -> SetPathStatusError
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for SetPathStatusError
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for SetPathStatusError
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for SetPathStatusError
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for SetPathStatusError
Source§
fn eq(&self, other: &SetPathStatusError) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for SetPathStatusError
Source§
impl StructuralPartialEq for SetPathStatusError
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/n0_nat_traversal/enum.Error.html b/pr/616/docs/noq_proto/n0_nat_traversal/enum.Error.html
index 8b860033b..3a4a18d65 100644
--- a/pr/616/docs/noq_proto/n0_nat_traversal/enum.Error.html
+++ b/pr/616/docs/noq_proto/n0_nat_traversal/enum.Error.html
@@ -1,4 +1,4 @@
-Error in noq_proto::n0_nat_traversal - Rust
Error
noq_proto::n0_nat_traversal
Enum Error 
Source 
pub enum Error {
+Error in noq_proto::n0_nat_traversal - Rust
Error
noq_proto::n0_nat_traversal
Enum Error 
Source 
pub enum Error {
     TooManyAddresses,
     WrongConnectionSide,
     ExtensionNotNegotiated,
@@ -12,7 +12,7 @@
 
§
NotEnoughAddresses
Not enough addresses to complete the operation

 
§
Multipath(PathError)
Nat traversal attempt failed due to a multipath error

 
§
Closed
Attempted to initiate NAT traversal on a closed, or closing connection.

-
Trait Implementations§
Source§
impl Debug for Error
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for Error
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for Error
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Auto Trait Implementations§
§
impl Freeze for Error
§
impl RefUnwindSafe for Error
§
impl Send for Error
§
impl Sync for Error
§
impl Unpin for Error
§
impl UnwindSafe for Error
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Debug for Error
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for Error
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for Error
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Auto Trait Implementations§
§
impl Freeze for Error
§
impl RefUnwindSafe for Error
§
impl Send for Error
§
impl Sync for Error
§
impl Unpin for Error
§
impl UnwindSafe for Error
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> From<T> for T
Source§
fn from(t: T) -> T
Returns the argument unchanged.

diff --git a/pr/616/docs/noq_proto/n0_nat_traversal/enum.Event.html b/pr/616/docs/noq_proto/n0_nat_traversal/enum.Event.html
index ba59da0d3..816cbd846 100644
--- a/pr/616/docs/noq_proto/n0_nat_traversal/enum.Event.html
+++ b/pr/616/docs/noq_proto/n0_nat_traversal/enum.Event.html
@@ -1,10 +1,10 @@
-Event in noq_proto::n0_nat_traversal - Rust
Event
noq_proto::n0_nat_traversal
Enum Event 
Source 
pub enum Event {
+Event in noq_proto::n0_nat_traversal - Rust
Event
noq_proto::n0_nat_traversal
Enum Event 
Source 
pub enum Event {
     AddressAdded(SocketAddr),
     AddressRemoved(SocketAddr),
 }
Expand description
Event emitted when the client receives ADD_ADDRESS or REMOVE_ADDRESS frames.

 
Variants§
§
AddressAdded(SocketAddr)
An ADD_ADDRESS frame was received.

 
§
AddressRemoved(SocketAddr)
A REMOVE_ADDRESS frame was received.

-
Trait Implementations§
Source§
impl Clone for Event
Source§
fn clone(&self) -> Event
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for Event
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Auto Trait Implementations§
§
impl Freeze for Event
§
impl RefUnwindSafe for Event
§
impl Send for Event
§
impl Sync for Event
§
impl Unpin for Event
§
impl UnwindSafe for Event
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Clone for Event
Source§
fn clone(&self) -> Event
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for Event
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Auto Trait Implementations§
§
impl Freeze for Event
§
impl RefUnwindSafe for Event
§
impl Send for Event
§
impl Sync for Event
§
impl Unpin for Event
§
impl UnwindSafe for Event
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/n0_nat_traversal/index.html b/pr/616/docs/noq_proto/n0_nat_traversal/index.html
index 4b718cd34..0cfd28f3d 100644
--- a/pr/616/docs/noq_proto/n0_nat_traversal/index.html
+++ b/pr/616/docs/noq_proto/n0_nat_traversal/index.html
@@ -1,2 +1,2 @@
-noq_proto::n0_nat_traversal - Rust
Module n0_nat_traversal
noq_proto
Module n0_nat_traversal 
Source 
Expand description
n0’s (https://n0.computer) NAT Traversal protocol implementation.

+noq_proto::n0_nat_traversal - Rust
Module n0_nat_traversal
noq_proto
Module n0_nat_traversal 
Source 
Expand description
n0’s (https://n0.computer) NAT Traversal protocol implementation.

 
Enums§
Error
Errors that the nat traversal state might encounter.
Event
Event emitted when the client receives ADD_ADDRESS or REMOVE_ADDRESS frames.

\ No newline at end of file
diff --git a/pr/616/docs/noq_proto/struct.ClosedPath.html b/pr/616/docs/noq_proto/struct.ClosedPath.html
index 15d3ebfbd..22054481b 100644
--- a/pr/616/docs/noq_proto/struct.ClosedPath.html
+++ b/pr/616/docs/noq_proto/struct.ClosedPath.html
@@ -1,6 +1,6 @@
-ClosedPath in noq_proto - Rust
ClosedPath
noq_proto
Struct ClosedPath 
Source 
pub struct ClosedPath { /* private fields */ }
Expand description
Error indicating that a path has not been opened or has already been abandoned

-
Trait Implementations§
Source§
impl Clone for ClosedPath
Source§
fn clone(&self) -> ClosedPath
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ClosedPath
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Default for ClosedPath
Source§
fn default() -> ClosedPath
Returns the “default value” for a type. Read more
Source§
impl Display for ClosedPath
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for ClosedPath
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for ClosedPath
Source§
fn eq(&self, other: &ClosedPath) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
-and should not be overridden without very good reason.
Source§
impl Eq for ClosedPath
Source§
impl StructuralPartialEq for ClosedPath
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+ClosedPath in noq_proto - Rust
ClosedPath
noq_proto
Struct ClosedPath 
Source 
pub struct ClosedPath { /* private fields */ }
Expand description
Error indicating that a path has not been opened or has already been abandoned

+
Trait Implementations§
Source§
impl Clone for ClosedPath
Source§
fn clone(&self) -> ClosedPath
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for ClosedPath
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Default for ClosedPath
Source§
fn default() -> ClosedPath
Returns the “default value” for a type. Read more
Source§
impl Display for ClosedPath
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for ClosedPath
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl PartialEq for ClosedPath
Source§
fn eq(&self, other: &ClosedPath) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+and should not be overridden without very good reason.
Source§
impl Eq for ClosedPath
Source§
impl StructuralPartialEq for ClosedPath
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/struct.Connection.html b/pr/616/docs/noq_proto/struct.Connection.html
index 8a5961490..acf0bad12 100644
--- a/pr/616/docs/noq_proto/struct.Connection.html
+++ b/pr/616/docs/noq_proto/struct.Connection.html
@@ -33,7 +33,7 @@ increasing time. Specifically, calling Instant may be interleaved in any order with a
 call to handle_event at that same instant; however
 events or timeouts with different instants must not be interleaved.

-
Implementations§
Source§
impl Connection
Source
pub fn poll_timeout(&mut self) -> Option<Instant>
Returns the next time at which handle_timeout should be called

+
Implementations§
Source§
impl Connection
Source
pub fn poll_timeout(&mut self) -> Option<Instant>
Returns the next time at which handle_timeout should be called

 
The value returned may change after:

 
    
 
  • the application performed some I/O on the connection
    • 
@@ -124,42 +124,42 @@ idle time. Setting None disables the timeout and stops the timer.
 
    max_datagrams specifies how many datagrams can be returned inside a
 single Transmit using GSO. This must be at least 1.
    
-
Source
pub fn handle_event(&mut self, event: ConnectionEvent)
Process ConnectionEvents generated by the associated Endpoint

+
Source
pub fn handle_event(&mut self, event: ConnectionEvent)
Process ConnectionEvents generated by the associated Endpoint

 
Will execute protocol logic upon receipt of a connection event, in turn preparing signals
 (including application Events, EndpointEvents and outgoing datagrams) that should be
 extracted through the relevant methods.

-
Source
pub fn handle_timeout(&mut self, now: Instant)
Process timer expirations

+
Source
pub fn handle_timeout(&mut self, now: Instant)
Process timer expirations

 
Executes protocol logic, potentially preparing signals (including application Events,
 EndpointEvents and outgoing datagrams) that should be extracted through the relevant
 methods.

 
It is most efficient to call this immediately after the system clock reaches the latest
 Instant that was output by poll_timeout; however spurious extra calls will simply
 no-op and therefore are safe.

-
Source
pub fn close(&mut self, now: Instant, error_code: VarInt, reason: Bytes)
Close a connection immediately

+
Source
pub fn close(&mut self, now: Instant, error_code: VarInt, reason: Bytes)
Close a connection immediately

 
This does not ensure delivery of outstanding data. It is the application’s responsibility to
 call this only when all important communications have been completed, e.g. by calling
 SendStream::finish on outstanding streams and waiting for the corresponding
 StreamEvent::Finished event.

 
If Streams::send_streams returns 0, all outstanding stream data has been
 delivered. There may still be data from the peer that has not been received.

-
Source
pub fn datagrams(&mut self) -> Datagrams<'_>
Control datagrams

-
Source
pub fn stats(&mut self) -> ConnectionStats
Returns connection statistics

-
Source
pub fn path_stats(&mut self, path_id: PathId) -> Option<PathStats>
Returns path statistics

-
Source
pub fn ping(&mut self)
Ping the remote endpoint

+
Source
pub fn datagrams(&mut self) -> Datagrams<'_>
Control datagrams

+
Source
pub fn stats(&mut self) -> ConnectionStats
Returns connection statistics

+
Source
pub fn path_stats(&mut self, path_id: PathId) -> Option<PathStats>
Returns path statistics

+
Source
pub fn ping(&mut self)
Ping the remote endpoint

 
Causes an ACK-eliciting packet to be transmitted on the connection.

-
Source
pub fn ping_path(&mut self, path: PathId) -> Result<(), ClosedPath>
Ping the remote endpoint over a specific path

+
Source
pub fn ping_path(&mut self, path: PathId) -> Result<(), ClosedPath>
Ping the remote endpoint over a specific path

 
Causes an ACK-eliciting packet to be transmitted on the path.

-
Source
pub fn force_key_update(&mut self)
Update traffic keys spontaneously

+
Source
pub fn force_key_update(&mut self)
Update traffic keys spontaneously

 
This can be useful for testing key updates, as they otherwise only happen infrequently.

-
Source
pub fn crypto_session(&self) -> &dyn Session
Get a session reference

-
Source
pub fn is_handshaking(&self) -> bool
Whether the connection is in the process of being established

+
Source
pub fn crypto_session(&self) -> &dyn Session
Get a session reference

+
Source
pub fn is_handshaking(&self) -> bool
Whether the connection is in the process of being established

 
If this returns false, the connection may be either established or closed, signaled by the
 emission of a Connected or ConnectionLost
 event respectively. Note that locally-initiated closes via close() do not
 emit a ConnectionLost event.

 
For an established connection this essentially means the handshake is completed,
 but not necessarily yet confirmed.

-
Source
pub fn is_closed(&self) -> bool
Whether the connection is closed

+
Source
pub fn is_closed(&self) -> bool
Whether the connection is closed

 
Closed connections cannot transport any further data. A connection becomes closed when
 either peer application intentionally closes it, or when either transport layer detects an
 error such as a time-out or certificate validation failure.

@@ -167,24 +167,24 @@ error such as a time-out or certificate validation failure.

 connection is closed by the peer or due to an error. When the local application closes
 the connection via close(), no ConnectionLost event is emitted;
 instead, pending operations fail with ConnectionError::LocallyClosed.

-
Source
pub fn is_drained(&self) -> bool
Whether there is no longer any need to keep the connection around

+
Source
pub fn is_drained(&self) -> bool
Whether there is no longer any need to keep the connection around

 
Closed connections become drained after a brief timeout to absorb any remaining in-flight
 packets from the peer. All drained connections have been closed.

-
Source
pub fn accepted_0rtt(&self) -> bool
For clients, if the peer accepted the 0-RTT data packets

+
Source
pub fn accepted_0rtt(&self) -> bool
For clients, if the peer accepted the 0-RTT data packets

 
The value is meaningless until after the handshake completes.

-
Source
pub fn has_0rtt(&self) -> bool
Whether 0-RTT is/was possible during the handshake

-
Source
pub fn has_pending_retransmits(&self) -> bool
Whether there are any pending retransmits

-
Source
pub fn side(&self) -> Side
Look up whether we’re the client or server of this Connection

-
Source
pub fn path_observed_address(
+
Source
pub fn has_0rtt(&self) -> bool
Whether 0-RTT is/was possible during the handshake

+
Source
pub fn has_pending_retransmits(&self) -> bool
Whether there are any pending retransmits

+
Source
pub fn side(&self) -> Side
Look up whether we’re the client or server of this Connection

+
Source
pub fn path_observed_address(
     &self,
     path_id: PathId,
 ) -> Result<Option<SocketAddr>, ClosedPath>
Get the address observed by the remote over the given path

-
Source
pub fn rtt(&self, path_id: PathId) -> Option<Duration>
Current best estimate of this connection’s latency (round-trip-time)

-
Source
pub fn congestion_state(&self, path_id: PathId) -> Option<&dyn Controller>
Current state of this connection’s congestion controller, for debugging purposes

-
Source
pub fn set_max_concurrent_streams(&mut self, dir: Dir, count: VarInt)
Modify the number of remotely initiated streams that may be concurrently open

+
Source
pub fn rtt(&self, path_id: PathId) -> Option<Duration>
Current best estimate of this connection’s latency (round-trip-time)

+
Source
pub fn congestion_state(&self, path_id: PathId) -> Option<&dyn Controller>
Current state of this connection’s congestion controller, for debugging purposes

+
Source
pub fn set_max_concurrent_streams(&mut self, dir: Dir, count: VarInt)
Modify the number of remotely initiated streams that may be concurrently open

 
No streams may be opened by the peer unless fewer than count are already open. Large
 counts increase both minimum and worst-case memory consumption.

-
Source
pub fn set_max_concurrent_paths(
+
Source
pub fn set_max_concurrent_paths(
     &mut self,
     now: Instant,
     count: NonZeroU32,
@@ -195,16 +195,16 @@ actively reduce paths they must be closed using TransportConfig) this can not enable
 multipath and will fail.

-
Source
pub fn max_concurrent_streams(&self, dir: Dir) -> u64
Current number of remotely initiated streams that may be concurrently open

+
Source
pub fn max_concurrent_streams(&self, dir: Dir) -> u64
Current number of remotely initiated streams that may be concurrently open

 
If the target for this limit is reduced using set_max_concurrent_streams,
 it will not change immediately, even if fewer streams are open. Instead, it will
 decrement by one for each time a remotely initiated stream of matching directionality is closed.

-
Source
pub fn set_send_window(&mut self, send_window: u64)
See TransportConfig::send_window()

-
Source
pub fn set_receive_window(&mut self, receive_window: VarInt)
See TransportConfig::receive_window()

-
Source
pub fn is_multipath_negotiated(&self) -> bool
Whether the Multipath for QUIC extension is enabled.

+
Source
pub fn set_send_window(&mut self, send_window: u64)
See TransportConfig::send_window()

+
Source
pub fn set_receive_window(&mut self, receive_window: VarInt)
See TransportConfig::receive_window()

+
Source
pub fn is_multipath_negotiated(&self) -> bool
Whether the Multipath for QUIC extension is enabled.

 
Multipath is only enabled after the handshake is completed and if it was enabled by both
 peers.

-
Source
pub fn handle_network_change(
+
Source
pub fn handle_network_change(
     &mut self,
     hint: Option<&dyn NetworkChangeHint>,
     now: Instant,
@@ -219,26 +219,26 @@ paths as non recoverable when necessary accelerates connectivity re-establishmen
 allow it altogether.

 
The optional hint allows callers to indicate when paths are non-recoverable and should be
 migrated to new a PathId.

-
Source
pub fn current_mtu(&self) -> u16
Storage size required for the largest packet that can be transmitted on all currently
+
Source
pub fn current_mtu(&self) -> u16
Storage size required for the largest packet that can be transmitted on all currently
 available paths

 
Buffers passed to Connection::poll_transmit should be at least this large.

 
When multipath is enabled, this value is the minimum MTU across all available paths.

-
Source
pub fn add_nat_traversal_address(
+
Source
pub fn add_nat_traversal_address(
     &mut self,
     address: SocketAddr,
 ) -> Result<(), Error>
Add addresses the local endpoint considers are reachable for nat traversal.

-
Source
pub fn remove_nat_traversal_address(
+
Source
pub fn remove_nat_traversal_address(
     &mut self,
     address: SocketAddr,
 ) -> Result<(), Error>
Removes an address the endpoing no longer considers reachable for nat traversal

 
Addresses not present in the set will be silently ignored.

-
Source
pub fn get_local_nat_traversal_addresses(
+
Source
pub fn get_local_nat_traversal_addresses(
     &self,
 ) -> Result<Vec<SocketAddr>, Error>
Get the current local nat traversal addresses

-
Source
pub fn get_remote_nat_traversal_addresses(
+
Source
pub fn get_remote_nat_traversal_addresses(
     &self,
 ) -> Result<Vec<SocketAddr>, Error>
Get the currently advertised nat traversal addresses by the server

-
Source
pub fn initiate_nat_traversal_round(
+
Source
pub fn initiate_nat_traversal_round(
     &mut self,
     now: Instant,
 ) -> Result<Vec<SocketAddr>, Error>
Initiates a new nat traversal round

@@ -249,7 +249,7 @@ round is initiated, the previous one is cancelled.

 4-tuple.

 
Returns the server addresses that are now being probed. If addresses fail due to
 spurious errors, these might succeed later and not be returned in this set.

-
Trait Implementations§
Source§
impl Debug for Connection
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Trait Implementations§
Source§
impl Debug for Connection
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> From<T> for T
Source§
fn from(t: T) -> T
Returns the argument unchanged.

diff --git a/pr/616/docs/noq_proto/struct.MultipathNotNegotiated.html b/pr/616/docs/noq_proto/struct.MultipathNotNegotiated.html
index 4ed1904f2..d3f05c79e 100644
--- a/pr/616/docs/noq_proto/struct.MultipathNotNegotiated.html
+++ b/pr/616/docs/noq_proto/struct.MultipathNotNegotiated.html
@@ -1,5 +1,5 @@
-MultipathNotNegotiated in noq_proto - Rust
MultipathNotNegotiated
noq_proto
Struct MultipathNotNegotiated 
Source 
pub struct MultipathNotNegotiated { /* private fields */ }
Expand description
Error when the multipath extension was not negotiated, but attempted to be used.

-
Trait Implementations§
Source§
impl Clone for MultipathNotNegotiated
Source§
fn clone(&self) -> MultipathNotNegotiated
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for MultipathNotNegotiated
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for MultipathNotNegotiated
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for MultipathNotNegotiated
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl Copy for MultipathNotNegotiated
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+MultipathNotNegotiated in noq_proto - Rust
MultipathNotNegotiated
noq_proto
Struct MultipathNotNegotiated 
Source 
pub struct MultipathNotNegotiated { /* private fields */ }
Expand description
Error when the multipath extension was not negotiated, but attempted to be used.

+
Trait Implementations§
Source§
impl Clone for MultipathNotNegotiated
Source§
fn clone(&self) -> MultipathNotNegotiated
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for MultipathNotNegotiated
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for MultipathNotNegotiated
Source§
fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for MultipathNotNegotiated
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl Copy for MultipathNotNegotiated
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/struct.RttEstimator.html b/pr/616/docs/noq_proto/struct.RttEstimator.html
index d6c03ab12..50807c4f0 100644
--- a/pr/616/docs/noq_proto/struct.RttEstimator.html
+++ b/pr/616/docs/noq_proto/struct.RttEstimator.html
@@ -1,10 +1,10 @@
-RttEstimator in noq_proto - Rust
RttEstimator
noq_proto
Struct RttEstimator 
Source 
pub struct RttEstimator { /* private fields */ }
Expand description
RTT estimation for a particular network path

-
Implementations§
Source§
impl RttEstimator
Source
pub fn get(&self) -> Duration
The current best RTT estimation.

-
Source
pub fn conservative(&self) -> Duration
Conservative estimate of RTT

+RttEstimator in noq_proto - Rust
RttEstimator
noq_proto
Struct RttEstimator 
Source 
pub struct RttEstimator { /* private fields */ }
Expand description
RTT estimation for a particular network path

+
Implementations§
Source§
impl RttEstimator
Source
pub fn get(&self) -> Duration
The current best RTT estimation.

+
Source
pub fn conservative(&self) -> Duration
Conservative estimate of RTT

 
Takes the maximum of smoothed and latest RTT, as recommended
 in 6.1.2 of the recovery spec (draft 29).

-
Source
pub fn min(&self) -> Duration
Minimum RTT registered so far for this estimator.

-
Trait Implementations§
Source§
impl Clone for RttEstimator
Source§
fn clone(&self) -> RttEstimator
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for RttEstimator
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Copy for RttEstimator
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
+
Source
pub fn min(&self) -> Duration
Minimum RTT registered so far for this estimator.

+
Trait Implementations§
Source§
impl Clone for RttEstimator
Source§
fn clone(&self) -> RttEstimator
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for RttEstimator
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Copy for RttEstimator
Auto Trait Implementations§
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
     T: ?Sized,
Source§
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§
impl<T> CloneToUninit for T
where
diff --git a/pr/616/docs/noq_proto/struct.TransportError.html b/pr/616/docs/noq_proto/struct.TransportError.html
index 243d857c4..9eabadc9d 100644
--- a/pr/616/docs/noq_proto/struct.TransportError.html
+++ b/pr/616/docs/noq_proto/struct.TransportError.html
@@ -11,7 +11,7 @@
 
§reason: String
Human-readable explanation of the reason

 
§crypto: Option<Arc<dyn Error + Send + Sync>>
An underlying crypto (e.g. TLS) layer error

 
Implementations§
Source§
impl Error
Source
pub fn new(code: Code, reason: String) -> Self
Construct an error with a code and a reason

-
Trait Implementations§
Source§
impl Clone for Error
Source§
fn clone(&self) -> Error
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for Error
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for Error
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for Error
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl From<Error> for ConnectionClose
Source§
fn from(x: TransportError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for ConnectionError
Source§
fn from(source: TransportError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for TransportError
Source§
fn from(e: Error) -> Self
Converts to this type from the input type.
Source§
impl PartialEq for Error
Source§
fn eq(&self, other: &Self) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
+
Trait Implementations§
Source§
impl Clone for Error
Source§
fn clone(&self) -> Error
Returns a duplicate of the value. Read more
1.0.0 · Source§
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
Source§
impl Debug for Error
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Display for Error
Source§
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
Source§
impl Error for Error
1.30.0 · Source§
fn source(&self) -> Option<&(dyn Error + 'static)>
Returns the lower-level source of this error, if any. Read more
1.0.0 · Source§
fn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
 Read more
1.0.0 · Source§
fn cause(&self) -> Option<&dyn Error>
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
Source§
fn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type-based access to context intended for error reports. Read more
Source§
impl From<Error> for ConnectionClose
Source§
fn from(x: TransportError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for ConnectionError
Source§
fn from(source: TransportError) -> Self
Converts to this type from the input type.
Source§
impl From<Error> for TransportError
Source§
fn from(e: Error) -> Self
Converts to this type from the input type.
Source§
impl PartialEq for Error
Source§
fn eq(&self, other: &Self) -> bool
Tests for self and other values to be equal, and is used by ==.
1.0.0 · Source§
fn ne(&self, other: &Rhs) -> bool
Tests for !=. The default implementation is almost always sufficient,
 and should not be overridden without very good reason.
Source§
impl Eq for Error
Auto Trait Implementations§
§
impl Freeze for Error
§
impl !RefUnwindSafe for Error
§
impl Send for Error
§
impl Sync for Error
§
impl Unpin for Error
§
impl !UnwindSafe for Error
Blanket Implementations§
Source§
impl<T> Any for T
where
     T: 'static + ?Sized,
Source§
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
Source§
impl<T> Borrow<T> for T
where
     T: ?Sized,
Source§
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
Source§
impl<T> BorrowMut<T> for T
where
diff --git a/pr/616/docs/noq_proto/trait.NetworkChangeHint.html b/pr/616/docs/noq_proto/trait.NetworkChangeHint.html
index 25d57b29d..0f19ec7e4 100644
--- a/pr/616/docs/noq_proto/trait.NetworkChangeHint.html
+++ b/pr/616/docs/noq_proto/trait.NetworkChangeHint.html
@@ -1,4 +1,4 @@
-NetworkChangeHint in noq_proto - Rust
NetworkChangeHint
noq_proto
Trait NetworkChangeHint 
Source 
pub trait NetworkChangeHint: Debug + 'static {
+NetworkChangeHint in noq_proto - Rust
NetworkChangeHint
noq_proto
Trait NetworkChangeHint 
Source 
pub trait NetworkChangeHint: Debug + 'static {
     // Required method
     fn is_path_recoverable(
         &self,
@@ -6,7 +6,7 @@
         network_path: FourTuple,
     ) -> bool;
 }
Expand description
Hints when the caller identifies a network change.

-
Required Methods§
Source
fn is_path_recoverable(&self, path_id: PathId, network_path: FourTuple) -> bool
Inform the connection if a path may recover after a network change.

+
Required Methods§
Source
fn is_path_recoverable(&self, path_id: PathId, network_path: FourTuple) -> bool
Inform the connection if a path may recover after a network change.

 
After network changes, paths may not be recoverable. In this case, waiting for the path to
 become idle may take longer than what is desirable. If Self::is_path_recoverable
 returns false, a multipath-enabled, client-side connection will establish a new path to
diff --git a/pr/616/docs/settings.html b/pr/616/docs/settings.html
index 1adf3f67d..fc24471ee 100644
--- a/pr/616/docs/settings.html
+++ b/pr/616/docs/settings.html
@@ -1 +1 @@
-Settings
All
Rustdoc settings
Back

\ No newline at end of file
+Settings
All
Rustdoc settings
Back

\ No newline at end of file
diff --git a/pr/616/docs/src/noq_proto/connection/mod.rs.html b/pr/616/docs/src/noq_proto/connection/mod.rs.html
index 98a167cff..a719d88f7 100644
--- a/pr/616/docs/src/noq_proto/connection/mod.rs.html
+++ b/pr/616/docs/src/noq_proto/connection/mod.rs.html
@@ -3,7 +3,7 @@
 3    collections::{BTreeMap, VecDeque, btree_map},
 4    convert::TryFrom,
 5    fmt, io, mem,
-6    net::{IpAddr, SocketAddr},
+6    net::SocketAddr,
 7    num::{NonZeroU32, NonZeroUsize},
 8    sync::Arc,
 9};
@@ -81,7 +81,7 @@
 81pub(crate) mod qlog;
 82pub(crate) mod send_buffer;
 83
-84mod spaces;
+84pub(crate) mod spaces;
 85#[cfg(fuzzing)]
 86pub use spaces::Retransmits;
 87#[cfg(not(fuzzing))]
@@ -1991,5802 +1991,5676 @@
 1991            .udp_tx
 1992            .on_sent(1, buf.len());
 1993
-1994        Some(Transmit {
-1995            destination: network_path.remote,
-1996            size: buf.len(),
-1997            ecn: None,
-1998            segment_size: None,
-1999            src_ip: network_path.local_ip,
-2000        })
-2001    }
-2002
-2003    fn send_off_path_path_response(
-2004        &mut self,
-2005        now: Instant,
-2006        buf: &mut Vec<u8>,
-2007        path_id: PathId,
-2008    ) -> Option<Transmit> {
-2009        let path = self.paths.get_mut(&path_id).map(|state| &mut state.data)?;
-2010        let cid_queue = self.remote_cids.get_mut(&path_id)?;
-2011        let (token, network_path) = path.path_responses.pop_off_path(path.network_path)?;
-2012
-2013        let cid = cid_queue
-2014            .next_reserved()
-2015            .unwrap_or_else(|| cid_queue.active());
-2016        // TODO(@divma): we should take a different approach when there is no fresh CID to use.
-2017        // https://github.com/quinn-rs/quinn/issues/2184
+1994        trace!(
+1995            dst = ?network_path.remote,
+1996            src = ?network_path.local_ip,
+1997            len = buf.len(),
+1998            "sending prev_path off-path challenge",
+1999        );
+2000        Some(Transmit {
+2001            destination: network_path.remote,
+2002            size: buf.len(),
+2003            ecn: None,
+2004            segment_size: None,
+2005            src_ip: network_path.local_ip,
+2006        })
+2007    }
+2008
+2009    fn send_off_path_path_response(
+2010        &mut self,
+2011        now: Instant,
+2012        buf: &mut Vec<u8>,
+2013        path_id: PathId,
+2014    ) -> Option<Transmit> {
+2015        let path = self.paths.get_mut(&path_id).map(|state| &mut state.data)?;
+2016        let cid_queue = self.remote_cids.get_mut(&path_id)?;
+2017        let (token, network_path) = path.path_responses.pop_off_path(path.network_path)?;
 2018
-2019        let frame = frame::PathResponse(token);
-2020
-2021        let buf = &mut TransmitBuf::new(buf, NonZeroUsize::MIN, MIN_INITIAL_SIZE.into());
-2022        buf.start_new_datagram();
-2023
-2024        let mut builder = PacketBuilder::new(now, SpaceId::Data, path_id, cid, buf, self)?;
-2025        let stats = &mut self.path_stats.for_path(path_id).frame_tx;
-2026        builder.write_frame_with_log_msg(frame, stats, Some("(off-path)"));
-2027        // Off-path: not tracked in congestion control. The packet is sent to a
-2028        // different destination than path_id's network path.
-2029        builder.pad_to(MIN_INITIAL_SIZE);
-2030        builder.finish(self, now);
-2031
-2032        let size = buf.len();
-2033
-2034        self.path_stats.for_path(path_id).udp_tx.on_sent(1, size);
-2035        Some(Transmit {
-2036            destination: network_path.remote,
-2037            size,
-2038            ecn: None,
-2039            segment_size: None,
-2040            src_ip: network_path.local_ip,
-2041        })
-2042    }
-2043
-2044    /// Send a nat traversal challenge (off-path) on this path if possible.
-2045    fn send_nat_traversal_path_challenge(
-2046        &mut self,
-2047        now: Instant,
-2048        buf: &mut Vec<u8>,
-2049        path_id: PathId,
-2050    ) -> Option<Transmit> {
-2051        let remote = self
-2052            .n0_nat_traversal
-2053            .server_side_mut()
-2054            .ok()?
-2055            .next_probe_addr()?;
-2056
-2057        if !self.paths.get(&path_id)?.data.validated {
-2058            // Path is not usable for probing
-2059            return None;
-2060        }
-2061
-2062        // TODO: Using the active CID here makes the paths linkable. This is a violation of
-2063        //    RFC9000 but something we want to accept in the short term. Eventually we aim
-2064        //    to fix up the supply of CIDs sufficiently so that we can keep paths unlinkable
-2065        //    again.
-2066        let Some(cid) = self
-2067            .remote_cids
-2068            .get(&path_id)
-2069            .map(|cid_queue| cid_queue.active())
-2070        else {
-2071            trace!(%path_id, "Not sending NAT traversal probe for path with no CIDs");
-2072            return None;
-2073        };
-2074        let token = self.rng.random();
-2075
-2076        let frame = frame::PathChallenge(token);
-2077
-2078        let mut buf = TransmitBuf::new(buf, NonZeroUsize::MIN, MIN_INITIAL_SIZE.into());
-2079        buf.start_new_datagram();
-2080
-2081        let mut builder = PacketBuilder::new(now, SpaceId::Data, path_id, cid, &mut buf, self)?;
-2082        let stats = &mut self.path_stats.for_path(path_id).frame_tx;
-2083        builder.write_frame_with_log_msg(frame, stats, Some("(nat-traversal)"));
-2084        // Off-path: not tracked in congestion control. The packet is sent to a
-2085        // different destination than path_id's network path.
-2086        builder.finish(self, now);
-2087
-2088        // Mark as sent after packet build succeeds.
-2089        if let Ok(server_state) = self.n0_nat_traversal.server_side_mut() {
-2090            server_state.mark_probe_sent((remote.ip(), remote.port()), token);
-2091        }
-2092
-2093        let size = buf.len();
-2094
-2095        self.path_stats.for_path(path_id).udp_tx.on_sent(1, size);
-2096
-2097        Some(Transmit {
-2098            destination: remote,
-2099            size,
-2100            ecn: None,
-2101            segment_size: None,
-2102            src_ip: None,
-2103        })
-2104    }
-2105
-2106    /// Indicate what types of frames are ready to send for the given space.
-2107    ///
-2108    /// Only for on-path data.
-2109    ///
-2110    /// *packet_size* is the number of bytes available to build the next packet.
-2111    /// *connection_close_pending* indicates whether a CONNECTION_CLOSE frame needs to be
-2112    /// sent.
-2113    fn space_can_send(
-2114        &mut self,
-2115        space_id: SpaceId,
-2116        path_id: PathId,
-2117        packet_size: usize,
-2118        connection_close_pending: bool,
-2119    ) -> SendableFrames {
-2120        let space = &mut self.spaces[space_id];
-2121        let space_has_crypto = self.crypto_state.has_keys(space_id.encryption_level());
-2122
-2123        if !space_has_crypto
-2124            && (space_id != SpaceId::Data
-2125                || !self.crypto_state.has_keys(EncryptionLevel::ZeroRtt)
-2126                || self.side.is_server())
-2127        {
-2128            // Nothing to send in this space
-2129            return SendableFrames::empty();
-2130        }
-2131
-2132        let mut can_send = space.can_send(path_id, &self.streams);
-2133
-2134        // Check for 1RTT space.
-2135        if space_id == SpaceId::Data {
-2136            let pn = space.for_path(path_id).peek_tx_number();
-2137            // Number of bytes available for frames if this is a 1-RTT packet. We're
-2138            // guaranteed to be able to send an individual frame at least this large in the
-2139            // next 1-RTT packet. This could be generalized to support every space, but it's
-2140            // only needed to handle large fixed-size frames, which only exist in 1-RTT
-2141            // (application datagrams).
-2142            let frame_space_1rtt =
-2143                packet_size.saturating_sub(self.predict_1rtt_overhead(pn, path_id));
-2144            can_send |= self.can_send_1rtt(path_id, frame_space_1rtt);
-2145        }
-2146
-2147        can_send.close = connection_close_pending && space_has_crypto;
-2148
-2149        can_send
-2150    }
-2151
-2152    /// Process `ConnectionEvent`s generated by the associated `Endpoint`
-2153    ///
-2154    /// Will execute protocol logic upon receipt of a connection event, in turn preparing signals
-2155    /// (including application `Event`s, `EndpointEvent`s and outgoing datagrams) that should be
-2156    /// extracted through the relevant methods.
-2157    pub fn handle_event(&mut self, event: ConnectionEvent) {
-2158        use ConnectionEventInner::*;
-2159        match event.0 {
-2160            Datagram(DatagramConnectionEvent {
-2161                now,
-2162                network_path,
-2163                path_id,
-2164                ecn,
-2165                first_decode,
-2166                remaining,
-2167            }) => {
-2168                let span = trace_span!("pkt", %path_id);
-2169                let _guard = span.enter();
-2170
-2171                if self.early_discard_packet(network_path, path_id) {
-2172                    // A return value of true indicates we should discard this packet.
-2173                    return;
-2174                }
-2175
-2176                let was_anti_amplification_blocked = self
-2177                    .path(path_id)
-2178                    .map(|path| path.anti_amplification_blocked(1))
-2179                    // We never tried to send on an non-existing (new) path so have not been
-2180                    // anti-amplification blocked for it previously.
-2181                    .unwrap_or(false);
+2019        let cid = cid_queue
+2020            .next_reserved()
+2021            .unwrap_or_else(|| cid_queue.active());
+2022        // TODO(@divma): we should take a different approach when there is no fresh CID to use.
+2023        // https://github.com/quinn-rs/quinn/issues/2184
+2024
+2025        let frame = frame::PathResponse(token);
+2026
+2027        let buf = &mut TransmitBuf::new(buf, NonZeroUsize::MIN, MIN_INITIAL_SIZE.into());
+2028        buf.start_new_datagram();
+2029
+2030        let mut builder = PacketBuilder::new(now, SpaceId::Data, path_id, cid, buf, self)?;
+2031        let stats = &mut self.path_stats.for_path(path_id).frame_tx;
+2032        builder.write_frame_with_log_msg(frame, stats, Some("(off-path)"));
+2033        // Off-path: not tracked in congestion control. The packet is sent to a
+2034        // different destination than path_id's network path.
+2035        builder.pad_to(MIN_INITIAL_SIZE);
+2036        builder.finish(self, now);
+2037
+2038        let size = buf.len();
+2039        self.path_stats.for_path(path_id).udp_tx.on_sent(1, size);
+2040
+2041        trace!(
+2042            dst = ?network_path.remote,
+2043            src = ?network_path.local_ip,
+2044            len = buf.len(),
+2045            "sending off-path PATH_RESPONSE",
+2046        );
+2047        Some(Transmit {
+2048            destination: network_path.remote,
+2049            size,
+2050            ecn: None,
+2051            segment_size: None,
+2052            src_ip: network_path.local_ip,
+2053        })
+2054    }
+2055
+2056    /// Send a nat traversal challenge (off-path) on this path if possible.
+2057    fn send_nat_traversal_path_challenge(
+2058        &mut self,
+2059        now: Instant,
+2060        buf: &mut Vec<u8>,
+2061        path_id: PathId,
+2062    ) -> Option<Transmit> {
+2063        let remote = self.n0_nat_traversal.next_probe_addr()?;
+2064
+2065        if !self.paths.get(&path_id)?.data.validated {
+2066            // Path is not usable for probing
+2067            return None;
+2068        }
+2069
+2070        // TODO: Using the active CID here makes the paths linkable. This is a violation of
+2071        //    RFC9000 but something we want to accept in the short term. Eventually we aim
+2072        //    to fix up the supply of CIDs sufficiently so that we can keep paths unlinkable
+2073        //    again.
+2074        let Some(cid) = self
+2075            .remote_cids
+2076            .get(&path_id)
+2077            .map(|cid_queue| cid_queue.active())
+2078        else {
+2079            trace!(%path_id, "Not sending NAT traversal probe for path with no CIDs");
+2080            return None;
+2081        };
+2082        let token = self.rng.random();
+2083
+2084        let frame = frame::PathChallenge(token);
+2085
+2086        let mut buf = TransmitBuf::new(buf, NonZeroUsize::MIN, MIN_INITIAL_SIZE.into());
+2087        buf.start_new_datagram();
+2088
+2089        let mut builder = PacketBuilder::new(now, SpaceId::Data, path_id, cid, &mut buf, self)?;
+2090        let stats = &mut self.path_stats.for_path(path_id).frame_tx;
+2091        builder.write_frame_with_log_msg(frame, stats, Some("(nat-traversal)"));
+2092        // Off-path: not tracked in congestion control. The packet is sent to a
+2093        // different destination than path_id's network path.
+2094        builder.finish(self, now);
+2095
+2096        // Mark as sent after packet build succeeds.
+2097        self.n0_nat_traversal
+2098            .mark_probe_sent((remote.ip(), remote.port()), token);
+2099
+2100        let size = buf.len();
+2101        self.path_stats.for_path(path_id).udp_tx.on_sent(1, size);
+2102
+2103        trace!(dst = ?remote, len = buf.len(), "sending off-path NAT probe");
+2104        Some(Transmit {
+2105            destination: remote,
+2106            size,
+2107            ecn: None,
+2108            segment_size: None,
+2109            src_ip: None,
+2110        })
+2111    }
+2112
+2113    /// Indicate what types of frames are ready to send for the given space.
+2114    ///
+2115    /// Only for on-path data.
+2116    ///
+2117    /// *packet_size* is the number of bytes available to build the next packet.
+2118    /// *connection_close_pending* indicates whether a CONNECTION_CLOSE frame needs to be
+2119    /// sent.
+2120    fn space_can_send(
+2121        &mut self,
+2122        space_id: SpaceId,
+2123        path_id: PathId,
+2124        packet_size: usize,
+2125        connection_close_pending: bool,
+2126    ) -> SendableFrames {
+2127        let space = &mut self.spaces[space_id];
+2128        let space_has_crypto = self.crypto_state.has_keys(space_id.encryption_level());
+2129
+2130        if !space_has_crypto
+2131            && (space_id != SpaceId::Data
+2132                || !self.crypto_state.has_keys(EncryptionLevel::ZeroRtt)
+2133                || self.side.is_server())
+2134        {
+2135            // Nothing to send in this space
+2136            return SendableFrames::empty();
+2137        }
+2138
+2139        let mut can_send = space.can_send(path_id, &self.streams);
+2140
+2141        // Check for 1RTT space.
+2142        if space_id == SpaceId::Data {
+2143            let pn = space.for_path(path_id).peek_tx_number();
+2144            // Number of bytes available for frames if this is a 1-RTT packet. We're
+2145            // guaranteed to be able to send an individual frame at least this large in the
+2146            // next 1-RTT packet. This could be generalized to support every space, but it's
+2147            // only needed to handle large fixed-size frames, which only exist in 1-RTT
+2148            // (application datagrams).
+2149            let frame_space_1rtt =
+2150                packet_size.saturating_sub(self.predict_1rtt_overhead(pn, path_id));
+2151            can_send |= self.can_send_1rtt(path_id, frame_space_1rtt);
+2152        }
+2153
+2154        can_send.close = connection_close_pending && space_has_crypto;
+2155
+2156        can_send
+2157    }
+2158
+2159    /// Process `ConnectionEvent`s generated by the associated `Endpoint`
+2160    ///
+2161    /// Will execute protocol logic upon receipt of a connection event, in turn preparing signals
+2162    /// (including application `Event`s, `EndpointEvent`s and outgoing datagrams) that should be
+2163    /// extracted through the relevant methods.
+2164    pub fn handle_event(&mut self, event: ConnectionEvent) {
+2165        use ConnectionEventInner::*;
+2166        match event.0 {
+2167            Datagram(DatagramConnectionEvent {
+2168                now,
+2169                network_path,
+2170                path_id,
+2171                ecn,
+2172                first_decode,
+2173                remaining,
+2174            }) => {
+2175                let span = trace_span!("pkt", %path_id);
+2176                let _guard = span.enter();
+2177
+2178                if self.early_discard_packet(network_path, path_id) {
+2179                    // A return value of true indicates we should discard this packet.
+2180                    return;
+2181                }
 2182
-2183                let rx = &mut self.path_stats.for_path(path_id).udp_rx;
-2184                rx.datagrams += 1;
-2185                rx.bytes += first_decode.len() as u64;
-2186                let data_len = first_decode.len();
-2187
-2188                self.handle_decode(now, network_path, path_id, ecn, first_decode);
-2189                // The current `path` might have changed inside `handle_decode` since the packet
-2190                // could have triggered a migration. The packet might also belong to an unknown
-2191                // path and have been rejected. Make sure the data received is accounted for the
-2192                // most recent path by accessing `path` after `handle_decode`.
-2193                if let Some(path) = self.path_mut(path_id) {
-2194                    path.inc_total_recvd(data_len as u64);
-2195                }
-2196
-2197                if let Some(data) = remaining {
-2198                    self.path_stats.for_path(path_id).udp_rx.bytes += data.len() as u64;
-2199                    self.handle_coalesced(now, network_path, path_id, ecn, data);
-2200                }
-2201
-2202                if let Some(path) = self.paths.get_mut(&path_id) {
-2203                    self.qlog
-2204                        .emit_recovery_metrics(path_id, &mut path.data, now);
-2205                }
-2206
-2207                if was_anti_amplification_blocked {
-2208                    // A prior attempt to set the loss detection timer may have failed due to
-2209                    // anti-amplification, so ensure it's set now. Prevents a handshake deadlock if
-2210                    // the server's first flight is lost.
-2211                    self.set_loss_detection_timer(now, path_id);
+2183                let was_anti_amplification_blocked = self
+2184                    .path(path_id)
+2185                    .map(|path| path.anti_amplification_blocked(1))
+2186                    // We never tried to send on an non-existing (new) path so have not been
+2187                    // anti-amplification blocked for it previously.
+2188                    .unwrap_or(false);
+2189
+2190                let rx = &mut self.path_stats.for_path(path_id).udp_rx;
+2191                rx.datagrams += 1;
+2192                rx.bytes += first_decode.len() as u64;
+2193                let data_len = first_decode.len();
+2194
+2195                self.handle_decode(now, network_path, path_id, ecn, first_decode);
+2196                // The current `path` might have changed inside `handle_decode` since the packet
+2197                // could have triggered a migration. The packet might also belong to an unknown
+2198                // path and have been rejected. Make sure the data received is accounted for the
+2199                // most recent path by accessing `path` after `handle_decode`.
+2200                if let Some(path) = self.path_mut(path_id) {
+2201                    path.inc_total_recvd(data_len as u64);
+2202                }
+2203
+2204                if let Some(data) = remaining {
+2205                    self.path_stats.for_path(path_id).udp_rx.bytes += data.len() as u64;
+2206                    self.handle_coalesced(now, network_path, path_id, ecn, data);
+2207                }
+2208
+2209                if let Some(path) = self.paths.get_mut(&path_id) {
+2210                    self.qlog
+2211                        .emit_recovery_metrics(path_id, &mut path.data, now);
 2212                }
-2213            }
-2214            NewIdentifiers(ids, now, cid_len, cid_lifetime) => {
-2215                let path_id = ids.first().map(|issued| issued.path_id).unwrap_or_default();
-2216                debug_assert!(ids.iter().all(|issued| issued.path_id == path_id));
-2217                let cid_state = self
-2218                    .local_cid_state
-2219                    .entry(path_id)
-2220                    .or_insert_with(|| CidState::new(cid_len, cid_lifetime, now, 0));
-2221                cid_state.new_cids(&ids, now);
-2222
-2223                ids.into_iter().rev().for_each(|frame| {
-2224                    self.spaces[SpaceId::Data].pending.new_cids.push(frame);
-2225                });
-2226                // Always update Timer::PushNewCid
-2227                self.reset_cid_retirement(now);
-2228            }
-2229        }
-2230    }
-2231
-2232    /// Returns whether a packet can be discarded early.
-2233    ///
-2234    /// Packets sent on the wrong network path can be entirely ignored, saving further
-2235    /// processing.
-2236    ///
-2237    /// Returns true if a packet coming in for this `path_id` over given `network_path`
-2238    /// should be discarded.
-2239    fn early_discard_packet(&mut self, network_path: FourTuple, path_id: PathId) -> bool {
-2240        if self.is_handshaking() && path_id != PathId::ZERO {
-2241            debug!(%network_path, %path_id, "discarding multipath packet during handshake");
-2242            return true;
-2243        }
-2244
-2245        // TODO(flub): In RFC9000 the server is allowed to send off-path probing packets
-2246        //    once the client has been probing such a 4-tuple. These probes are currently
-2247        //    not yet recognised and discarded here.
-2248        //    See https://github.com/n0-computer/noq/issues/607.
-2249        let remote_may_migrate = self.remote_may_migrate();
-2250
-2251        let local_ip_may_migrate = self.local_ip_may_migrate();
-2252
-2253        // If this packet could initiate a migration and we're a client or a server that
-2254        // forbids migration, drop the datagram. This could be relaxed to heuristically
-2255        // permit NAT-rebinding-like migration.
-2256        if let Some(known_path) = self.path_mut(path_id) {
-2257            if network_path.remote != known_path.network_path.remote && !remote_may_migrate {
-2258                trace!(
-2259                    %path_id,
-2260                    %network_path,
-2261                    %known_path.network_path,
-2262                    "discarding packet from unrecognized peer"
-2263                );
-2264                return true;
-2265            }
-2266
-2267            if known_path.network_path.local_ip.is_some()
-2268                && network_path.local_ip.is_some()
-2269                && known_path.network_path.local_ip != network_path.local_ip
-2270                && !local_ip_may_migrate
-2271            {
-2272                trace!(
-2273                    %path_id,
-2274                    %network_path,
-2275                    %known_path.network_path,
-2276                    "discarding packet sent to incorrect interface"
-2277                );
-2278                return true;
-2279            }
-2280        }
-2281        false
-2282    }
-2283
-2284    /// Whether a remote is allowed to migrate.
-2285    ///
-2286    /// QUIC relies on stable endpoints during the handshake. So other than the server's
-2287    /// preferred_address transport parameter no side may migrate before the handshake is
-2288    /// completed.
-2289    ///
-2290    /// In RFC9000 only the client may migrate. If QNT is negotiated the server may migrate
-2291    /// as well.
+2213
+2214                if was_anti_amplification_blocked {
+2215                    // A prior attempt to set the loss detection timer may have failed due to
+2216                    // anti-amplification, so ensure it's set now. Prevents a handshake deadlock if
+2217                    // the server's first flight is lost.
+2218                    self.set_loss_detection_timer(now, path_id);
+2219                }
+2220            }
+2221            NewIdentifiers(ids, now, cid_len, cid_lifetime) => {
+2222                let path_id = ids.first().map(|issued| issued.path_id).unwrap_or_default();
+2223                debug_assert!(ids.iter().all(|issued| issued.path_id == path_id));
+2224                let cid_state = self
+2225                    .local_cid_state
+2226                    .entry(path_id)
+2227                    .or_insert_with(|| CidState::new(cid_len, cid_lifetime, now, 0));
+2228                cid_state.new_cids(&ids, now);
+2229
+2230                ids.into_iter().rev().for_each(|frame| {
+2231                    self.spaces[SpaceId::Data].pending.new_cids.push(frame);
+2232                });
+2233                // Always update Timer::PushNewCid
+2234                self.reset_cid_retirement(now);
+2235            }
+2236        }
+2237    }
+2238
+2239    /// Returns whether a packet can be discarded early.
+2240    ///
+2241    /// Packets sent on the wrong network path can be entirely ignored, saving further
+2242    /// processing.
+2243    ///
+2244    /// Returns true if a packet coming in for this `path_id` over given `network_path`
+2245    /// should be discarded.
+2246    fn early_discard_packet(&mut self, network_path: FourTuple, path_id: PathId) -> bool {
+2247        if self.is_handshaking() && path_id != PathId::ZERO {
+2248            debug!(%network_path, %path_id, "discarding multipath packet during handshake");
+2249            return true;
+2250        }
+2251
+2252        // TODO(flub): In RFC9000 the server is allowed to send off-path probing packets
+2253        //    once the client has been probing such a 4-tuple. These probes are currently
+2254        //    not yet recognised and discarded here.
+2255        //    See https://github.com/n0-computer/noq/issues/607.
+2256        let remote_may_migrate = self.remote_may_migrate();
+2257
+2258        let local_ip_may_migrate = self.local_ip_may_migrate();
+2259
+2260        // If this packet could initiate a migration and we're a client or a server that
+2261        // forbids migration, drop the datagram. This could be relaxed to heuristically
+2262        // permit NAT-rebinding-like migration.
+2263        if let Some(known_path) = self.path_mut(path_id) {
+2264            if network_path.remote != known_path.network_path.remote && !remote_may_migrate {
+2265                trace!(
+2266                    %path_id,
+2267                    %network_path,
+2268                    %known_path.network_path,
+2269                    "discarding packet from unrecognized peer"
+2270                );
+2271                return true;
+2272            }
+2273
+2274            if known_path.network_path.local_ip.is_some()
+2275                && network_path.local_ip.is_some()
+2276                && known_path.network_path.local_ip != network_path.local_ip
+2277                && !local_ip_may_migrate
+2278            {
+2279                trace!(
+2280                    %path_id,
+2281                    %network_path,
+2282                    %known_path.network_path,
+2283                    "discarding packet sent to incorrect interface"
+2284                );
+2285                return true;
+2286            }
+2287        }
+2288        false
+2289    }
+2290
+2291    /// Whether a remote is allowed to migrate.
 2292    ///
-2293    /// Additionally for iroh we allow the server to migrate once during the handshake as
-2294    /// long as the client has not received an authenticated Handshake packet. This allows
-2295    /// us to duplicate client Initial packets to multiple destinations. See
-2296    /// [`state::Handshake::allow_server_migration`].
-2297    fn remote_may_migrate(&self) -> bool {
-2298        match &self.side {
-2299            ConnectionSide::Server { server_config } => {
-2300                server_config.migration && self.is_handshake_confirmed()
-2301            }
-2302            ConnectionSide::Client { .. } => {
-2303                if let Some(hs) = self.state.as_handshake() {
-2304                    hs.allow_server_migration
-2305                } else {
-2306                    self.n0_nat_traversal.is_negotiated() && self.is_handshake_confirmed()
-2307                }
+2293    /// QUIC relies on stable endpoints during the handshake. So other than the server's
+2294    /// preferred_address transport parameter no side may migrate before the handshake is
+2295    /// completed.
+2296    ///
+2297    /// In RFC9000 only the client may migrate. If QNT is negotiated the server may migrate
+2298    /// as well.
+2299    ///
+2300    /// Additionally for iroh we allow the server to migrate once during the handshake as
+2301    /// long as the client has not received an authenticated Handshake packet. This allows
+2302    /// us to duplicate client Initial packets to multiple destinations. See
+2303    /// [`state::Handshake::allow_server_migration`].
+2304    fn remote_may_migrate(&self) -> bool {
+2305        match &self.side {
+2306            ConnectionSide::Server { server_config } => {
+2307                server_config.migration && self.is_handshake_confirmed()
 2308            }
-2309        }
-2310    }
-2311
-2312    /// Whether our local IP address is allowed to change with new incoming packets.
-2313    ///
-2314    /// Incoming packets show us the local IP address we received a packet on, which could
-2315    /// be different from what we thought due to e.g. NAT rebinding or moving from mobile
-2316    /// data to WiFi without being notified of the network change.
-2317    ///
-2318    /// This is only allowed to happen after the handshake is confirmed and when we are the
-2319    /// client. Unless QNT is negotiated in which case the server is also allowed to
-2320    /// migrate.
-2321    ///
-2322    /// Be aware that probing packets, which do not exist in Multipath without QNT, are
-2323    /// exempt from this.
-2324    fn local_ip_may_migrate(&self) -> bool {
-2325        (self.side.is_client() || self.n0_nat_traversal.is_negotiated())
-2326            && self.is_handshake_confirmed()
-2327    }
-2328    /// Process timer expirations
-2329    ///
-2330    /// Executes protocol logic, potentially preparing signals (including application `Event`s,
-2331    /// `EndpointEvent`s and outgoing datagrams) that should be extracted through the relevant
-2332    /// methods.
-2333    ///
-2334    /// It is most efficient to call this immediately after the system clock reaches the latest
-2335    /// `Instant` that was output by `poll_timeout`; however spurious extra calls will simply
-2336    /// no-op and therefore are safe.
-2337    pub fn handle_timeout(&mut self, now: Instant) {
-2338        while let Some((timer, _time)) = self.timers.expire_before(now, &self.qlog) {
-2339            let span = match timer {
-2340                Timer::Conn(timer) => trace_span!("timeout", scope = "conn", ?timer),
-2341                Timer::PerPath(path_id, timer) => {
-2342                    trace_span!("timer_fired", scope="path", %path_id, ?timer)
-2343                }
-2344            };
-2345            let _guard = span.enter();
-2346            trace!("timeout");
-2347            match timer {
-2348                Timer::Conn(timer) => match timer {
-2349                    ConnTimer::Close => {
-2350                        self.state.move_to_drained(None);
-2351                        // move_to_drained checks that we weren't in drained before.
-2352                        // Adding events to endpoint_events is only legal if `Drained` was never queued before.
-2353                        self.endpoint_events.push_back(EndpointEventInner::Drained);
-2354                    }
-2355                    ConnTimer::Idle => {
-2356                        self.kill(ConnectionError::TimedOut);
-2357                    }
-2358                    ConnTimer::KeepAlive => {
-2359                        self.ping();
-2360                    }
-2361                    ConnTimer::KeyDiscard => {
-2362                        self.crypto_state.discard_temporary_keys();
-2363                    }
-2364                    ConnTimer::PushNewCid => {
-2365                        while let Some((path_id, when)) = self.next_cid_retirement() {
-2366                            if when > now {
-2367                                break;
-2368                            }
-2369                            match self.local_cid_state.get_mut(&path_id) {
-2370                                None => error!(%path_id, "No local CID state for path"),
-2371                                Some(cid_state) => {
-2372                                    // Update `retire_prior_to` field in NEW_CONNECTION_ID frame
-2373                                    let num_new_cid = cid_state.on_cid_timeout().into();
-2374                                    if !self.state.is_closed() {
-2375                                        trace!(
-2376                                            "push a new CID to peer RETIRE_PRIOR_TO field {}",
-2377                                            cid_state.retire_prior_to()
-2378                                        );
-2379                                        self.endpoint_events.push_back(
-2380                                            EndpointEventInner::NeedIdentifiers(
-2381                                                path_id,
-2382                                                now,
-2383                                                num_new_cid,
-2384                                            ),
+2309            ConnectionSide::Client { .. } => {
+2310                if let Some(hs) = self.state.as_handshake() {
+2311                    hs.allow_server_migration
+2312                } else {
+2313                    self.n0_nat_traversal.is_negotiated() && self.is_handshake_confirmed()
+2314                }
+2315            }
+2316        }
+2317    }
+2318
+2319    /// Whether our local IP address is allowed to change with new incoming packets.
+2320    ///
+2321    /// Incoming packets show us the local IP address we received a packet on, which could
+2322    /// be different from what we thought due to e.g. NAT rebinding or moving from mobile
+2323    /// data to WiFi without being notified of the network change.
+2324    ///
+2325    /// This is only allowed to happen after the handshake is confirmed and when we are the
+2326    /// client. Unless QNT is negotiated in which case the server is also allowed to
+2327    /// migrate.
+2328    ///
+2329    /// Be aware that probing packets, which do not exist in Multipath without QNT, are
+2330    /// exempt from this.
+2331    fn local_ip_may_migrate(&self) -> bool {
+2332        (self.side.is_client() || self.n0_nat_traversal.is_negotiated())
+2333            && self.is_handshake_confirmed()
+2334    }
+2335    /// Process timer expirations
+2336    ///
+2337    /// Executes protocol logic, potentially preparing signals (including application `Event`s,
+2338    /// `EndpointEvent`s and outgoing datagrams) that should be extracted through the relevant
+2339    /// methods.
+2340    ///
+2341    /// It is most efficient to call this immediately after the system clock reaches the latest
+2342    /// `Instant` that was output by `poll_timeout`; however spurious extra calls will simply
+2343    /// no-op and therefore are safe.
+2344    pub fn handle_timeout(&mut self, now: Instant) {
+2345        while let Some((timer, _time)) = self.timers.expire_before(now, &self.qlog) {
+2346            let span = match timer {
+2347                Timer::Conn(timer) => trace_span!("timeout", scope = "conn", ?timer),
+2348                Timer::PerPath(path_id, timer) => {
+2349                    trace_span!("timer_fired", scope="path", %path_id, ?timer)
+2350                }
+2351            };
+2352            let _guard = span.enter();
+2353            trace!("timeout");
+2354            match timer {
+2355                Timer::Conn(timer) => match timer {
+2356                    ConnTimer::Close => {
+2357                        self.state.move_to_drained(None);
+2358                        // move_to_drained checks that we weren't in drained before.
+2359                        // Adding events to endpoint_events is only legal if `Drained` was never queued before.
+2360                        self.endpoint_events.push_back(EndpointEventInner::Drained);
+2361                    }
+2362                    ConnTimer::Idle => {
+2363                        self.kill(ConnectionError::TimedOut);
+2364                    }
+2365                    ConnTimer::KeepAlive => {
+2366                        self.ping();
+2367                    }
+2368                    ConnTimer::KeyDiscard => {
+2369                        self.crypto_state.discard_temporary_keys();
+2370                    }
+2371                    ConnTimer::PushNewCid => {
+2372                        while let Some((path_id, when)) = self.next_cid_retirement() {
+2373                            if when > now {
+2374                                break;
+2375                            }
+2376                            match self.local_cid_state.get_mut(&path_id) {
+2377                                None => error!(%path_id, "No local CID state for path"),
+2378                                Some(cid_state) => {
+2379                                    // Update `retire_prior_to` field in NEW_CONNECTION_ID frame
+2380                                    let num_new_cid = cid_state.on_cid_timeout().into();
+2381                                    if !self.state.is_closed() {
+2382                                        trace!(
+2383                                            "push a new CID to peer RETIRE_PRIOR_TO field {}",
+2384                                            cid_state.retire_prior_to()
 2385                                        );
-2386                                    }
-2387                                }
-2388                            }
-2389                        }
-2390                    }
-2391                    ConnTimer::NoAvailablePath => {
-2392                        // Grace period expired: all paths were abandoned and no new path
-2393                        // was opened. Close the connection. There are no paths left to
-2394                        // send CONNECTION_CLOSE on, so this is a silent close.
-2395                        // https://www.ietf.org/archive/id/draft-ietf-quic-multipath-21.html#section-3.4-8
-2396                        if self.state.is_closed() || self.state.is_drained() {
-2397                            // Connection already closing/drained (e.g. application called
-2398                            // close() before the grace timer fired). Nothing to do.
-2399                            error!("no viable path timer fired, but connection already closing");
-2400                        } else {
-2401                            trace!("no viable path grace period expired, closing connection");
-2402                            let err = TransportError::NO_VIABLE_PATH(
-2403                                "last path abandoned, no new path opened",
-2404                            );
-2405                            self.close_common();
-2406                            self.set_close_timer(now);
-2407                            self.connection_close_pending = true;
-2408                            self.state.move_to_closed(err);
-2409                        }
-2410                    }
-2411                    ConnTimer::NatTraversalProbeRetry => {
-2412                        if let Ok(server_state) = self.n0_nat_traversal.server_side_mut()
-2413                            && server_state.queue_retries()
-2414                        {
-2415                            let delay =
-2416                                RttEstimator::new(self.config.initial_rtt).pto_base() * 2 / 3;
-2417                            self.timers.set(
-2418                                Timer::Conn(ConnTimer::NatTraversalProbeRetry),
-2419                                now + delay,
-2420                                self.qlog.with_time(now),
-2421                            );
-2422                            trace!("off-path probe retry timer fired, re-queued probes");
-2423                        }
-2424                    }
-2425                },
-2426                Timer::PerPath(path_id, timer) => {
-2427                    match timer {
-2428                        PathTimer::PathIdle => {
-2429                            if let Err(err) =
-2430                                self.close_path_inner(now, path_id, PathAbandonReason::TimedOut)
-2431                            {
-2432                                warn!(?err, "failed closing path");
-2433                            }
-2434                        }
-2435
-2436                        PathTimer::PathKeepAlive => {
-2437                            self.ping_path(path_id).ok();
-2438                        }
-2439                        PathTimer::LossDetection => {
-2440                            self.on_loss_detection_timeout(now, path_id);
-2441                            self.qlog.emit_recovery_metrics(
-2442                                path_id,
-2443                                &mut self
-2444                                    .paths
-2445                                    .get_mut(&path_id)
-2446                                    .expect("loss-detection timer fires only on live paths")
-2447                                    .data,
-2448                                now,
-2449                            );
-2450                        }
-2451                        PathTimer::PathValidationFailed => {
-2452                            let Some(path) = self.paths.get_mut(&path_id) else {
-2453                                continue;
-2454                            };
-2455                            self.timers.stop(
-2456                                Timer::PerPath(path_id, PathTimer::PathChallengeLost),
-2457                                self.qlog.with_time(now),
-2458                            );
-2459                            debug!("path migration validation failed");
-2460                            if let Some((_, prev)) = path.prev.take() {
-2461                                path.data = prev;
-2462                            }
-2463                            path.data.reset_on_path_challenges();
-2464                        }
-2465                        PathTimer::PathChallengeLost => {
-2466                            let Some(path) = self.paths.get_mut(&path_id) else {
-2467                                continue;
-2468                            };
-2469                            trace!("path challenge deemed lost");
-2470                            path.data.pending_on_path_challenge = true;
+2386                                        self.endpoint_events.push_back(
+2387                                            EndpointEventInner::NeedIdentifiers(
+2388                                                path_id,
+2389                                                now,
+2390                                                num_new_cid,
+2391                                            ),
+2392                                        );
+2393                                    }
+2394                                }
+2395                            }
+2396                        }
+2397                    }
+2398                    ConnTimer::NoAvailablePath => {
+2399                        // Grace period expired: all paths were abandoned and no new path
+2400                        // was opened. Close the connection. There are no paths left to
+2401                        // send CONNECTION_CLOSE on, so this is a silent close.
+2402                        // https://www.ietf.org/archive/id/draft-ietf-quic-multipath-21.html#section-3.4-8
+2403                        if self.state.is_closed() || self.state.is_drained() {
+2404                            // Connection already closing/drained (e.g. application called
+2405                            // close() before the grace timer fired). Nothing to do.
+2406                            error!("no viable path timer fired, but connection already closing");
+2407                        } else {
+2408                            trace!("no viable path grace period expired, closing connection");
+2409                            let err = TransportError::NO_VIABLE_PATH(
+2410                                "last path abandoned, no new path opened",
+2411                            );
+2412                            self.close_common();
+2413                            self.set_close_timer(now);
+2414                            self.connection_close_pending = true;
+2415                            self.state.move_to_closed(err);
+2416                        }
+2417                    }
+2418                    ConnTimer::NatTraversalProbeRetry => {
+2419                        if self.n0_nat_traversal.queue_retries(self.is_ipv6()) {
+2420                            let delay =
+2421                                RttEstimator::new(self.config.initial_rtt).pto_base() * 2 / 3;
+2422                            self.timers.set(
+2423                                Timer::Conn(ConnTimer::NatTraversalProbeRetry),
+2424                                now + delay,
+2425                                self.qlog.with_time(now),
+2426                            );
+2427                            trace!("re-queued NAT probes");
+2428                        } else {
+2429                            trace!("no more NAT probes remaining");
+2430                        }
+2431                    }
+2432                },
+2433                Timer::PerPath(path_id, timer) => {
+2434                    match timer {
+2435                        PathTimer::PathIdle => {
+2436                            if let Err(err) =
+2437                                self.close_path_inner(now, path_id, PathAbandonReason::TimedOut)
+2438                            {
+2439                                warn!(?err, "failed closing path");
+2440                            }
+2441                        }
+2442
+2443                        PathTimer::PathKeepAlive => {
+2444                            self.ping_path(path_id).ok();
+2445                        }
+2446                        PathTimer::LossDetection => {
+2447                            self.on_loss_detection_timeout(now, path_id);
+2448                            self.qlog.emit_recovery_metrics(
+2449                                path_id,
+2450                                &mut self
+2451                                    .paths
+2452                                    .get_mut(&path_id)
+2453                                    .expect("loss-detection timer fires only on live paths")
+2454                                    .data,
+2455                                now,
+2456                            );
+2457                        }
+2458                        PathTimer::PathValidationFailed => {
+2459                            let Some(path) = self.paths.get_mut(&path_id) else {
+2460                                continue;
+2461                            };
+2462                            self.timers.stop(
+2463                                Timer::PerPath(path_id, PathTimer::PathChallengeLost),
+2464                                self.qlog.with_time(now),
+2465                            );
+2466                            debug!("path migration validation failed");
+2467                            if let Some((_, prev)) = path.prev.take() {
+2468                                path.data = prev;
+2469                            }
+2470                            path.data.reset_on_path_challenges();
 2471                        }
-2472                        PathTimer::AbandonFromValidation => {
+2472                        PathTimer::PathChallengeLost => {
 2473                            let Some(path) = self.paths.get_mut(&path_id) else {
 2474                                continue;
 2475                            };
-2476                            path.data.reset_on_path_challenges();
-2477                            self.timers.stop(
-2478                                Timer::PerPath(path_id, PathTimer::PathChallengeLost),
-2479                                self.qlog.with_time(now),
-2480                            );
-2481                            debug!("new path validation failed");
-2482                            if let Err(err) = self.close_path_inner(
-2483                                now,
-2484                                path_id,
-2485                                PathAbandonReason::ValidationFailed,
-2486                            ) {
-2487                                warn!(?err, "failed closing path");
-2488                            }
-2489                        }
-2490                        PathTimer::Pacing => {}
-2491                        PathTimer::MaxAckDelay => {
-2492                            // This timer is only armed in the Data space
-2493                            self.spaces[SpaceId::Data]
-2494                                .for_path(path_id)
-2495                                .pending_acks
-2496                                .on_max_ack_delay_timeout()
-2497                        }
-2498                        PathTimer::PathDrained => {
-2499                            // The path was abandoned and 3*PTO has expired since.  Clean up all
-2500                            // remaining state and install stateless reset token.
-2501                            self.timers.stop_per_path(path_id, self.qlog.with_time(now));
-2502                            if let Some(local_cid_state) = self.local_cid_state.remove(&path_id) {
-2503                                debug_assert!(!self.state.is_drained()); // requirement for endpoint_events. All timers should be cleared in drained connections.
-2504                                let (min_seq, max_seq) = local_cid_state.active_seq();
-2505                                for seq in min_seq..=max_seq {
-2506                                    self.endpoint_events.push_back(
-2507                                        EndpointEventInner::RetireConnectionId(
-2508                                            now, path_id, seq, false,
-2509                                        ),
-2510                                    );
-2511                                }
-2512                            }
-2513                            self.discard_path(path_id, now);
-2514                        }
-2515                    }
-2516                }
-2517            }
-2518        }
-2519    }
-2520
-2521    /// Close a connection immediately
-2522    ///
-2523    /// This does not ensure delivery of outstanding data. It is the application's responsibility to
-2524    /// call this only when all important communications have been completed, e.g. by calling
-2525    /// [`SendStream::finish`] on outstanding streams and waiting for the corresponding
-2526    /// [`StreamEvent::Finished`] event.
-2527    ///
-2528    /// If [`Streams::send_streams`] returns 0, all outstanding stream data has been
-2529    /// delivered. There may still be data from the peer that has not been received.
-2530    ///
-2531    /// [`StreamEvent::Finished`]: crate::StreamEvent::Finished
-2532    pub fn close(&mut self, now: Instant, error_code: VarInt, reason: Bytes) {
-2533        self.close_inner(
-2534            now,
-2535            Close::Application(frame::ApplicationClose { error_code, reason }),
-2536        )
-2537    }
-2538
-2539    /// Close the connection immediately, initiated by an API call.
-2540    ///
-2541    /// This will not produce a [`ConnectionLost`] event propagated by the
-2542    /// [`Connection::poll`] call, because the API call already propagated the error to the
-2543    /// user.
-2544    ///
-2545    /// Not to be used when entering immediate close due to an internal state change based
-2546    /// on an event. See [`State::move_to_closed_local`] for details.
+2476                            trace!("path challenge deemed lost");
+2477                            path.data.pending_on_path_challenge = true;
+2478                        }
+2479                        PathTimer::AbandonFromValidation => {
+2480                            let Some(path) = self.paths.get_mut(&path_id) else {
+2481                                continue;
+2482                            };
+2483                            path.data.reset_on_path_challenges();
+2484                            self.timers.stop(
+2485                                Timer::PerPath(path_id, PathTimer::PathChallengeLost),
+2486                                self.qlog.with_time(now),
+2487                            );
+2488                            debug!("new path validation failed");
+2489                            if let Err(err) = self.close_path_inner(
+2490                                now,
+2491                                path_id,
+2492                                PathAbandonReason::ValidationFailed,
+2493                            ) {
+2494                                warn!(?err, "failed closing path");
+2495                            }
+2496                        }
+2497                        PathTimer::Pacing => {}
+2498                        PathTimer::MaxAckDelay => {
+2499                            // This timer is only armed in the Data space
+2500                            self.spaces[SpaceId::Data]
+2501                                .for_path(path_id)
+2502                                .pending_acks
+2503                                .on_max_ack_delay_timeout()
+2504                        }
+2505                        PathTimer::PathDrained => {
+2506                            // The path was abandoned and 3*PTO has expired since.  Clean up all
+2507                            // remaining state and install stateless reset token.
+2508                            self.timers.stop_per_path(path_id, self.qlog.with_time(now));
+2509                            if let Some(local_cid_state) = self.local_cid_state.remove(&path_id) {
+2510                                debug_assert!(!self.state.is_drained()); // requirement for endpoint_events. All timers should be cleared in drained connections.
+2511                                let (min_seq, max_seq) = local_cid_state.active_seq();
+2512                                for seq in min_seq..=max_seq {
+2513                                    self.endpoint_events.push_back(
+2514                                        EndpointEventInner::RetireConnectionId(
+2515                                            now, path_id, seq, false,
+2516                                        ),
+2517                                    );
+2518                                }
+2519                            }
+2520                            self.discard_path(path_id, now);
+2521                        }
+2522                    }
+2523                }
+2524            }
+2525        }
+2526    }
+2527
+2528    /// Close a connection immediately
+2529    ///
+2530    /// This does not ensure delivery of outstanding data. It is the application's responsibility to
+2531    /// call this only when all important communications have been completed, e.g. by calling
+2532    /// [`SendStream::finish`] on outstanding streams and waiting for the corresponding
+2533    /// [`StreamEvent::Finished`] event.
+2534    ///
+2535    /// If [`Streams::send_streams`] returns 0, all outstanding stream data has been
+2536    /// delivered. There may still be data from the peer that has not been received.
+2537    ///
+2538    /// [`StreamEvent::Finished`]: crate::StreamEvent::Finished
+2539    pub fn close(&mut self, now: Instant, error_code: VarInt, reason: Bytes) {
+2540        self.close_inner(
+2541            now,
+2542            Close::Application(frame::ApplicationClose { error_code, reason }),
+2543        )
+2544    }
+2545
+2546    /// Close the connection immediately, initiated by an API call.
 2547    ///
-2548    /// This initiates immediate close from
-2549    /// <https://www.rfc-editor.org/rfc/rfc9000.html#section-10.2>, moving to the closed
-2550    /// state.
+2548    /// This will not produce a [`ConnectionLost`] event propagated by the
+2549    /// [`Connection::poll`] call, because the API call already propagated the error to the
+2550    /// user.
 2551    ///
-2552    /// [`ConnectionLost`]: crate::Event::ConnectionLost
-2553    /// [`Connection::poll`]: super::Connection::poll
-2554    fn close_inner(&mut self, now: Instant, reason: Close) {
-2555        let was_closed = self.state.is_closed();
-2556        if !was_closed {
-2557            self.close_common();
-2558            self.set_close_timer(now);
-2559            self.connection_close_pending = true;
-2560            self.state.move_to_closed_local(reason);
-2561        }
-2562    }
-2563
-2564    /// Control datagrams
-2565    pub fn datagrams(&mut self) -> Datagrams<'_> {
-2566        Datagrams { conn: self }
-2567    }
-2568
-2569    /// Returns connection statistics
-2570    pub fn stats(&mut self) -> ConnectionStats {
-2571        let mut stats = self.partial_stats.clone();
-2572
-2573        for path_stats in self.path_stats.iter_stats() {
-2574            // Self::path_stats() computes the path rtt, cwnd and current_mtu on access
-2575            // because they are not simple counters. When computing the connection stats we
-2576            // can skip that effort since those fields are not used in the `impl
-2577            // Add<PathStats> for ConnectionStats`.
-2578            stats += *path_stats;
-2579        }
-2580
-2581        stats
-2582    }
-2583
-2584    /// Returns path statistics
-2585    pub fn path_stats(&mut self, path_id: PathId) -> Option<PathStats> {
-2586        let path = self.paths.get(&path_id)?;
-2587        let stats = self.path_stats.for_path(path_id);
-2588        stats.rtt = path.data.rtt.get();
-2589        stats.cwnd = path.data.congestion.window();
-2590        stats.current_mtu = path.data.mtud.current_mtu();
-2591        Some(*stats)
-2592    }
-2593
-2594    /// Ping the remote endpoint
-2595    ///
-2596    /// Causes an ACK-eliciting packet to be transmitted on the connection.
-2597    pub fn ping(&mut self) {
-2598        // TODO(flub): This is very brute-force: it pings *all* the paths.  Instead it would
-2599        //    be nice if we could only send a single packet for this.
-2600        for path_data in self.spaces[self.highest_space].number_spaces.values_mut() {
-2601            path_data.ping_pending = true;
-2602        }
-2603    }
-2604
-2605    /// Ping the remote endpoint over a specific path
-2606    ///
-2607    /// Causes an ACK-eliciting packet to be transmitted on the path.
-2608    pub fn ping_path(&mut self, path: PathId) -> Result<(), ClosedPath> {
-2609        let path_data = self.spaces[self.highest_space]
-2610            .number_spaces
-2611            .get_mut(&path)
-2612            .ok_or(ClosedPath { _private: () })?;
-2613        path_data.ping_pending = true;
-2614        Ok(())
-2615    }
-2616
-2617    /// Update traffic keys spontaneously
-2618    ///
-2619    /// This can be useful for testing key updates, as they otherwise only happen infrequently.
-2620    pub fn force_key_update(&mut self) {
-2621        if !self.state.is_established() {
-2622            debug!("ignoring forced key update in illegal state");
-2623            return;
-2624        }
-2625        if self.crypto_state.prev_crypto.is_some() {
-2626            // We already just updated, or are currently updating, the keys. Concurrent key updates
-2627            // are illegal.
-2628            debug!("ignoring redundant forced key update");
-2629            return;
-2630        }
-2631        self.crypto_state.update_keys(None, false);
-2632    }
-2633
-2634    /// Get a session reference
-2635    pub fn crypto_session(&self) -> &dyn crypto::Session {
-2636        self.crypto_state.session.as_ref()
-2637    }
-2638
-2639    /// Whether the connection is in the process of being established
-2640    ///
-2641    /// If this returns `false`, the connection may be either established or closed, signaled by the
-2642    /// emission of a [`Connected`](Event::Connected) or [`ConnectionLost`](Event::ConnectionLost)
-2643    /// event respectively. Note that locally-initiated closes via [`close()`](Self::close) do not
-2644    /// emit a `ConnectionLost` event.
-2645    ///
-2646    /// For an established connection this essentially means the handshake is **completed**,
-2647    /// but not necessarily yet confirmed.
-2648    pub fn is_handshaking(&self) -> bool {
-2649        self.state.is_handshake()
-2650    }
-2651
-2652    /// Whether the connection is closed
-2653    ///
-2654    /// Closed connections cannot transport any further data. A connection becomes closed when
-2655    /// either peer application intentionally closes it, or when either transport layer detects an
-2656    /// error such as a time-out or certificate validation failure.
-2657    ///
-2658    /// A [`ConnectionLost`](Event::ConnectionLost) event is emitted with details when the
-2659    /// connection is closed by the peer or due to an error. When the local application closes
-2660    /// the connection via [`close()`](Self::close), no `ConnectionLost` event is emitted;
-2661    /// instead, pending operations fail with [`ConnectionError::LocallyClosed`].
-2662    pub fn is_closed(&self) -> bool {
-2663        self.state.is_closed()
-2664    }
-2665
-2666    /// Whether there is no longer any need to keep the connection around
-2667    ///
-2668    /// Closed connections become drained after a brief timeout to absorb any remaining in-flight
-2669    /// packets from the peer. All drained connections have been closed.
-2670    pub fn is_drained(&self) -> bool {
-2671        self.state.is_drained()
-2672    }
-2673
-2674    /// For clients, if the peer accepted the 0-RTT data packets
-2675    ///
-2676    /// The value is meaningless until after the handshake completes.
-2677    pub fn accepted_0rtt(&self) -> bool {
-2678        self.crypto_state.accepted_0rtt
+2552    /// Not to be used when entering immediate close due to an internal state change based
+2553    /// on an event. See [`State::move_to_closed_local`] for details.
+2554    ///
+2555    /// This initiates immediate close from
+2556    /// <https://www.rfc-editor.org/rfc/rfc9000.html#section-10.2>, moving to the closed
+2557    /// state.
+2558    ///
+2559    /// [`ConnectionLost`]: crate::Event::ConnectionLost
+2560    /// [`Connection::poll`]: super::Connection::poll
+2561    fn close_inner(&mut self, now: Instant, reason: Close) {
+2562        let was_closed = self.state.is_closed();
+2563        if !was_closed {
+2564            self.close_common();
+2565            self.set_close_timer(now);
+2566            self.connection_close_pending = true;
+2567            self.state.move_to_closed_local(reason);
+2568        }
+2569    }
+2570
+2571    /// Control datagrams
+2572    pub fn datagrams(&mut self) -> Datagrams<'_> {
+2573        Datagrams { conn: self }
+2574    }
+2575
+2576    /// Returns connection statistics
+2577    pub fn stats(&mut self) -> ConnectionStats {
+2578        let mut stats = self.partial_stats.clone();
+2579
+2580        for path_stats in self.path_stats.iter_stats() {
+2581            // Self::path_stats() computes the path rtt, cwnd and current_mtu on access
+2582            // because they are not simple counters. When computing the connection stats we
+2583            // can skip that effort since those fields are not used in the `impl
+2584            // Add<PathStats> for ConnectionStats`.
+2585            stats += *path_stats;
+2586        }
+2587
+2588        stats
+2589    }
+2590
+2591    /// Returns path statistics
+2592    pub fn path_stats(&mut self, path_id: PathId) -> Option<PathStats> {
+2593        let path = self.paths.get(&path_id)?;
+2594        let stats = self.path_stats.for_path(path_id);
+2595        stats.rtt = path.data.rtt.get();
+2596        stats.cwnd = path.data.congestion.window();
+2597        stats.current_mtu = path.data.mtud.current_mtu();
+2598        Some(*stats)
+2599    }
+2600
+2601    /// Ping the remote endpoint
+2602    ///
+2603    /// Causes an ACK-eliciting packet to be transmitted on the connection.
+2604    pub fn ping(&mut self) {
+2605        // TODO(flub): This is very brute-force: it pings *all* the paths.  Instead it would
+2606        //    be nice if we could only send a single packet for this.
+2607        for path_data in self.spaces[self.highest_space].number_spaces.values_mut() {
+2608            path_data.ping_pending = true;
+2609        }
+2610    }
+2611
+2612    /// Ping the remote endpoint over a specific path
+2613    ///
+2614    /// Causes an ACK-eliciting packet to be transmitted on the path.
+2615    pub fn ping_path(&mut self, path: PathId) -> Result<(), ClosedPath> {
+2616        let path_data = self.spaces[self.highest_space]
+2617            .number_spaces
+2618            .get_mut(&path)
+2619            .ok_or(ClosedPath { _private: () })?;
+2620        path_data.ping_pending = true;
+2621        Ok(())
+2622    }
+2623
+2624    /// Update traffic keys spontaneously
+2625    ///
+2626    /// This can be useful for testing key updates, as they otherwise only happen infrequently.
+2627    pub fn force_key_update(&mut self) {
+2628        if !self.state.is_established() {
+2629            debug!("ignoring forced key update in illegal state");
+2630            return;
+2631        }
+2632        if self.crypto_state.prev_crypto.is_some() {
+2633            // We already just updated, or are currently updating, the keys. Concurrent key updates
+2634            // are illegal.
+2635            debug!("ignoring redundant forced key update");
+2636            return;
+2637        }
+2638        self.crypto_state.update_keys(None, false);
+2639    }
+2640
+2641    /// Get a session reference
+2642    pub fn crypto_session(&self) -> &dyn crypto::Session {
+2643        self.crypto_state.session.as_ref()
+2644    }
+2645
+2646    /// Whether the connection is in the process of being established
+2647    ///
+2648    /// If this returns `false`, the connection may be either established or closed, signaled by the
+2649    /// emission of a [`Connected`](Event::Connected) or [`ConnectionLost`](Event::ConnectionLost)
+2650    /// event respectively. Note that locally-initiated closes via [`close()`](Self::close) do not
+2651    /// emit a `ConnectionLost` event.
+2652    ///
+2653    /// For an established connection this essentially means the handshake is **completed**,
+2654    /// but not necessarily yet confirmed.
+2655    pub fn is_handshaking(&self) -> bool {
+2656        self.state.is_handshake()
+2657    }
+2658
+2659    /// Whether the connection is closed
+2660    ///
+2661    /// Closed connections cannot transport any further data. A connection becomes closed when
+2662    /// either peer application intentionally closes it, or when either transport layer detects an
+2663    /// error such as a time-out or certificate validation failure.
+2664    ///
+2665    /// A [`ConnectionLost`](Event::ConnectionLost) event is emitted with details when the
+2666    /// connection is closed by the peer or due to an error. When the local application closes
+2667    /// the connection via [`close()`](Self::close), no `ConnectionLost` event is emitted;
+2668    /// instead, pending operations fail with [`ConnectionError::LocallyClosed`].
+2669    pub fn is_closed(&self) -> bool {
+2670        self.state.is_closed()
+2671    }
+2672
+2673    /// Whether there is no longer any need to keep the connection around
+2674    ///
+2675    /// Closed connections become drained after a brief timeout to absorb any remaining in-flight
+2676    /// packets from the peer. All drained connections have been closed.
+2677    pub fn is_drained(&self) -> bool {
+2678        self.state.is_drained()
 2679    }
 2680
-2681    /// Whether 0-RTT is/was possible during the handshake
-2682    pub fn has_0rtt(&self) -> bool {
-2683        self.crypto_state.zero_rtt_enabled
-2684    }
-2685
-2686    /// Whether there are any pending retransmits
-2687    pub fn has_pending_retransmits(&self) -> bool {
-2688        !self.spaces[SpaceId::Data].pending.is_empty(&self.streams)
-2689    }
-2690
-2691    /// Look up whether we're the client or server of this Connection
-2692    pub fn side(&self) -> Side {
-2693        self.side.side()
-2694    }
-2695
-2696    /// Get the address observed by the remote over the given path
-2697    pub fn path_observed_address(&self, path_id: PathId) -> Result<Option<SocketAddr>, ClosedPath> {
-2698        self.path(path_id)
-2699            .map(|path_data| {
-2700                path_data
-2701                    .last_observed_addr_report
-2702                    .as_ref()
-2703                    .map(|observed| observed.socket_addr())
-2704            })
-2705            .ok_or(ClosedPath { _private: () })
-2706    }
-2707
-2708    /// Current best estimate of this connection's latency (round-trip-time)
-2709    pub fn rtt(&self, path_id: PathId) -> Option<Duration> {
-2710        self.path(path_id).map(|d| d.rtt.get())
-2711    }
-2712
-2713    /// Current state of this connection's congestion controller, for debugging purposes
-2714    pub fn congestion_state(&self, path_id: PathId) -> Option<&dyn Controller> {
-2715        self.path(path_id).map(|d| d.congestion.as_ref())
-2716    }
-2717
-2718    /// Modify the number of remotely initiated streams that may be concurrently open
-2719    ///
-2720    /// No streams may be opened by the peer unless fewer than `count` are already open. Large
-2721    /// `count`s increase both minimum and worst-case memory consumption.
-2722    pub fn set_max_concurrent_streams(&mut self, dir: Dir, count: VarInt) {
-2723        self.streams.set_max_concurrent(dir, count);
-2724        // If the limit was reduced, then a flow control update previously deemed insignificant may
-2725        // now be significant.
-2726        let pending = &mut self.spaces[SpaceId::Data].pending;
-2727        self.streams.queue_max_stream_id(pending);
-2728    }
-2729
-2730    /// Modify the number of open paths allowed when multipath is enabled
-2731    ///
-2732    /// When reducing the number of concurrent paths this will only affect delaying sending
-2733    /// new MAX_PATH_ID frames until fewer than this number of paths are possible.  To
-2734    /// actively reduce paths they must be closed using [`Connection::close_path`], which
-2735    /// can also be used to close not-yet-opened paths.
-2736    ///
-2737    /// If multipath is not negotiated (see the [`TransportConfig`]) this can not enable
-2738    /// multipath and will fail.
-2739    pub fn set_max_concurrent_paths(
-2740        &mut self,
-2741        now: Instant,
-2742        count: NonZeroU32,
-2743    ) -> Result<(), MultipathNotNegotiated> {
-2744        if !self.is_multipath_negotiated() {
-2745            return Err(MultipathNotNegotiated { _private: () });
-2746        }
-2747        self.max_concurrent_paths = count;
-2748
-2749        let in_use_count = self
-2750            .local_max_path_id
-2751            .next()
-2752            .saturating_sub(self.abandoned_paths.len() as u32)
-2753            .as_u32();
-2754        let extra_needed = count.get().saturating_sub(in_use_count);
-2755        let new_max_path_id = self.local_max_path_id.saturating_add(extra_needed);
-2756
-2757        self.set_max_path_id(now, new_max_path_id);
-2758
-2759        Ok(())
-2760    }
-2761
-2762    /// If needed, issues a new MAX_PATH_ID frame and new CIDs for any newly allowed paths
-2763    fn set_max_path_id(&mut self, now: Instant, max_path_id: PathId) {
-2764        if max_path_id <= self.local_max_path_id {
-2765            return;
-2766        }
-2767
-2768        self.local_max_path_id = max_path_id;
-2769        self.spaces[SpaceId::Data].pending.max_path_id = true;
-2770
-2771        self.issue_first_path_cids(now);
-2772    }
-2773
-2774    /// Current number of remotely initiated streams that may be concurrently open
-2775    ///
-2776    /// If the target for this limit is reduced using [`set_max_concurrent_streams`](Self::set_max_concurrent_streams),
-2777    /// it will not change immediately, even if fewer streams are open. Instead, it will
-2778    /// decrement by one for each time a remotely initiated stream of matching directionality is closed.
-2779    pub fn max_concurrent_streams(&self, dir: Dir) -> u64 {
-2780        self.streams.max_concurrent(dir)
-2781    }
-2782
-2783    /// See [`TransportConfig::send_window()`]
-2784    pub fn set_send_window(&mut self, send_window: u64) {
-2785        self.streams.set_send_window(send_window);
-2786    }
-2787
-2788    /// See [`TransportConfig::receive_window()`]
-2789    pub fn set_receive_window(&mut self, receive_window: VarInt) {
-2790        if self.streams.set_receive_window(receive_window) {
-2791            self.spaces[SpaceId::Data].pending.max_data = true;
-2792        }
+2681    /// For clients, if the peer accepted the 0-RTT data packets
+2682    ///
+2683    /// The value is meaningless until after the handshake completes.
+2684    pub fn accepted_0rtt(&self) -> bool {
+2685        self.crypto_state.accepted_0rtt
+2686    }
+2687
+2688    /// Whether 0-RTT is/was possible during the handshake
+2689    pub fn has_0rtt(&self) -> bool {
+2690        self.crypto_state.zero_rtt_enabled
+2691    }
+2692
+2693    /// Whether there are any pending retransmits
+2694    pub fn has_pending_retransmits(&self) -> bool {
+2695        !self.spaces[SpaceId::Data].pending.is_empty(&self.streams)
+2696    }
+2697
+2698    /// Look up whether we're the client or server of this Connection
+2699    pub fn side(&self) -> Side {
+2700        self.side.side()
+2701    }
+2702
+2703    /// Get the address observed by the remote over the given path
+2704    pub fn path_observed_address(&self, path_id: PathId) -> Result<Option<SocketAddr>, ClosedPath> {
+2705        self.path(path_id)
+2706            .map(|path_data| {
+2707                path_data
+2708                    .last_observed_addr_report
+2709                    .as_ref()
+2710                    .map(|observed| observed.socket_addr())
+2711            })
+2712            .ok_or(ClosedPath { _private: () })
+2713    }
+2714
+2715    /// Current best estimate of this connection's latency (round-trip-time)
+2716    pub fn rtt(&self, path_id: PathId) -> Option<Duration> {
+2717        self.path(path_id).map(|d| d.rtt.get())
+2718    }
+2719
+2720    /// Current state of this connection's congestion controller, for debugging purposes
+2721    pub fn congestion_state(&self, path_id: PathId) -> Option<&dyn Controller> {
+2722        self.path(path_id).map(|d| d.congestion.as_ref())
+2723    }
+2724
+2725    /// Modify the number of remotely initiated streams that may be concurrently open
+2726    ///
+2727    /// No streams may be opened by the peer unless fewer than `count` are already open. Large
+2728    /// `count`s increase both minimum and worst-case memory consumption.
+2729    pub fn set_max_concurrent_streams(&mut self, dir: Dir, count: VarInt) {
+2730        self.streams.set_max_concurrent(dir, count);
+2731        // If the limit was reduced, then a flow control update previously deemed insignificant may
+2732        // now be significant.
+2733        let pending = &mut self.spaces[SpaceId::Data].pending;
+2734        self.streams.queue_max_stream_id(pending);
+2735    }
+2736
+2737    /// Modify the number of open paths allowed when multipath is enabled
+2738    ///
+2739    /// When reducing the number of concurrent paths this will only affect delaying sending
+2740    /// new MAX_PATH_ID frames until fewer than this number of paths are possible.  To
+2741    /// actively reduce paths they must be closed using [`Connection::close_path`], which
+2742    /// can also be used to close not-yet-opened paths.
+2743    ///
+2744    /// If multipath is not negotiated (see the [`TransportConfig`]) this can not enable
+2745    /// multipath and will fail.
+2746    pub fn set_max_concurrent_paths(
+2747        &mut self,
+2748        now: Instant,
+2749        count: NonZeroU32,
+2750    ) -> Result<(), MultipathNotNegotiated> {
+2751        if !self.is_multipath_negotiated() {
+2752            return Err(MultipathNotNegotiated { _private: () });
+2753        }
+2754        self.max_concurrent_paths = count;
+2755
+2756        let in_use_count = self
+2757            .local_max_path_id
+2758            .next()
+2759            .saturating_sub(self.abandoned_paths.len() as u32)
+2760            .as_u32();
+2761        let extra_needed = count.get().saturating_sub(in_use_count);
+2762        let new_max_path_id = self.local_max_path_id.saturating_add(extra_needed);
+2763
+2764        self.set_max_path_id(now, new_max_path_id);
+2765
+2766        Ok(())
+2767    }
+2768
+2769    /// If needed, issues a new MAX_PATH_ID frame and new CIDs for any newly allowed paths
+2770    fn set_max_path_id(&mut self, now: Instant, max_path_id: PathId) {
+2771        if max_path_id <= self.local_max_path_id {
+2772            return;
+2773        }
+2774
+2775        self.local_max_path_id = max_path_id;
+2776        self.spaces[SpaceId::Data].pending.max_path_id = true;
+2777
+2778        self.issue_first_path_cids(now);
+2779    }
+2780
+2781    /// Current number of remotely initiated streams that may be concurrently open
+2782    ///
+2783    /// If the target for this limit is reduced using [`set_max_concurrent_streams`](Self::set_max_concurrent_streams),
+2784    /// it will not change immediately, even if fewer streams are open. Instead, it will
+2785    /// decrement by one for each time a remotely initiated stream of matching directionality is closed.
+2786    pub fn max_concurrent_streams(&self, dir: Dir) -> u64 {
+2787        self.streams.max_concurrent(dir)
+2788    }
+2789
+2790    /// See [`TransportConfig::send_window()`]
+2791    pub fn set_send_window(&mut self, send_window: u64) {
+2792        self.streams.set_send_window(send_window);
 2793    }
 2794
-2795    /// Whether the Multipath for QUIC extension is enabled.
-2796    ///
-2797    /// Multipath is only enabled after the handshake is completed and if it was enabled by both
-2798    /// peers.
-2799    pub fn is_multipath_negotiated(&self) -> bool {
-2800        !self.is_handshaking()
-2801            && self.config.max_concurrent_multipath_paths.is_some()
-2802            && self.peer_params.initial_max_path_id.is_some()
-2803    }
-2804
-2805    fn on_ack_received(
-2806        &mut self,
-2807        now: Instant,
-2808        space: SpaceId,
-2809        ack: frame::Ack,
-2810    ) -> Result<(), TransportError> {
-2811        // All ACKs are referencing path 0
-2812        let path = PathId::ZERO;
-2813        self.inner_on_ack_received(now, space, path, ack)
-2814    }
-2815
-2816    fn on_path_ack_received(
-2817        &mut self,
-2818        now: Instant,
-2819        space: SpaceId,
-2820        path_ack: frame::PathAck,
-2821    ) -> Result<(), TransportError> {
-2822        let (ack, path) = path_ack.into_ack();
-2823        self.inner_on_ack_received(now, space, path, ack)
-2824    }
-2825
-2826    /// Handles an ACK frame acknowledging packets sent on *path*.
-2827    fn inner_on_ack_received(
-2828        &mut self,
-2829        now: Instant,
-2830        space: SpaceId,
-2831        path: PathId,
-2832        ack: frame::Ack,
-2833    ) -> Result<(), TransportError> {
-2834        if !self.spaces[space].number_spaces.contains_key(&path) {
-2835            if self.abandoned_paths.contains(&path) {
-2836                // See also
-2837                // https://www.ietf.org/archive/id/draft-ietf-quic-multipath-21.html#section-3.4.3-3
-2838                // > When an endpoint finally deletes all state associated with the path [...]
-2839                // > PATH_ACK frames received with an abandoned path ID are silently ignored,
-2840                // > as specified in Section 4.
-2841                trace!("silently ignoring PATH_ACK on discarded path");
-2842                return Ok(());
-2843            } else {
-2844                return Err(TransportError::PROTOCOL_VIOLATION(
-2845                    "received PATH_ACK with path ID never used",
-2846                ));
-2847            }
-2848        }
-2849        if ack.largest >= self.spaces[space].for_path(path).next_packet_number {
-2850            return Err(TransportError::PROTOCOL_VIOLATION("unsent packet acked"));
-2851        }
-2852        // `Some(pn)` if this ACK raised `largest_acked_packet_pn`.
-2853        let new_largest_pn = {
-2854            let space = &mut self.spaces[space].for_path(path);
-2855            if space
-2856                .largest_acked_packet_pn
-2857                .is_none_or(|pn| ack.largest > pn)
-2858            {
-2859                space.largest_acked_packet_pn = Some(ack.largest);
-2860                if let Some(info) = space.sent_packets.get(ack.largest) {
-2861                    // This should always succeed, but a misbehaving peer might ACK a packet we
-2862                    // haven't sent. At worst, that will result in us spuriously reducing the
-2863                    // congestion window.
-2864                    space.largest_acked_packet_send_time = info.time_sent;
-2865                }
-2866                Some(ack.largest)
-2867            } else {
-2868                None
-2869            }
-2870        };
-2871
-2872        if self.detect_spurious_loss(&ack, space, path) {
-2873            self.path_stats.for_path(path).spurious_congestion_events += 1;
-2874            self.path_data_mut(path)
-2875                .congestion
-2876                .on_spurious_congestion_event();
-2877        }
+2795    /// See [`TransportConfig::receive_window()`]
+2796    pub fn set_receive_window(&mut self, receive_window: VarInt) {
+2797        if self.streams.set_receive_window(receive_window) {
+2798            self.spaces[SpaceId::Data].pending.max_data = true;
+2799        }
+2800    }
+2801
+2802    /// Whether the Multipath for QUIC extension is enabled.
+2803    ///
+2804    /// Multipath is only enabled after the handshake is completed and if it was enabled by both
+2805    /// peers.
+2806    pub fn is_multipath_negotiated(&self) -> bool {
+2807        !self.is_handshaking()
+2808            && self.config.max_concurrent_multipath_paths.is_some()
+2809            && self.peer_params.initial_max_path_id.is_some()
+2810    }
+2811
+2812    fn on_ack_received(
+2813        &mut self,
+2814        now: Instant,
+2815        space: SpaceId,
+2816        ack: frame::Ack,
+2817    ) -> Result<(), TransportError> {
+2818        // All ACKs are referencing path 0
+2819        let path = PathId::ZERO;
+2820        self.inner_on_ack_received(now, space, path, ack)
+2821    }
+2822
+2823    fn on_path_ack_received(
+2824        &mut self,
+2825        now: Instant,
+2826        space: SpaceId,
+2827        path_ack: frame::PathAck,
+2828    ) -> Result<(), TransportError> {
+2829        let (ack, path) = path_ack.into_ack();
+2830        self.inner_on_ack_received(now, space, path, ack)
+2831    }
+2832
+2833    /// Handles an ACK frame acknowledging packets sent on *path*.
+2834    fn inner_on_ack_received(
+2835        &mut self,
+2836        now: Instant,
+2837        space: SpaceId,
+2838        path: PathId,
+2839        ack: frame::Ack,
+2840    ) -> Result<(), TransportError> {
+2841        if !self.spaces[space].number_spaces.contains_key(&path) {
+2842            if self.abandoned_paths.contains(&path) {
+2843                // See also
+2844                // https://www.ietf.org/archive/id/draft-ietf-quic-multipath-21.html#section-3.4.3-3
+2845                // > When an endpoint finally deletes all state associated with the path [...]
+2846                // > PATH_ACK frames received with an abandoned path ID are silently ignored,
+2847                // > as specified in Section 4.
+2848                trace!("silently ignoring PATH_ACK on discarded path");
+2849                return Ok(());
+2850            } else {
+2851                return Err(TransportError::PROTOCOL_VIOLATION(
+2852                    "received PATH_ACK with path ID never used",
+2853                ));
+2854            }
+2855        }
+2856        if ack.largest >= self.spaces[space].for_path(path).next_packet_number {
+2857            return Err(TransportError::PROTOCOL_VIOLATION("unsent packet acked"));
+2858        }
+2859        // `Some(pn)` if this ACK raised `largest_acked_packet_pn`.
+2860        let new_largest_pn = {
+2861            let space = &mut self.spaces[space].for_path(path);
+2862            if space
+2863                .largest_acked_packet_pn
+2864                .is_none_or(|pn| ack.largest > pn)
+2865            {
+2866                space.largest_acked_packet_pn = Some(ack.largest);
+2867                if let Some(info) = space.sent_packets.get(ack.largest) {
+2868                    // This should always succeed, but a misbehaving peer might ACK a packet we
+2869                    // haven't sent. At worst, that will result in us spuriously reducing the
+2870                    // congestion window.
+2871                    space.largest_acked_packet_send_time = info.time_sent;
+2872                }
+2873                Some(ack.largest)
+2874            } else {
+2875                None
+2876            }
+2877        };
 2878
-2879        // Avoid DoS from unreasonably huge ack ranges by filtering out just the new acks.
-2880        let mut newly_acked = ArrayRangeSet::new();
-2881        for range in ack.iter() {
-2882            self.spaces[space].for_path(path).check_ack(range.clone())?;
-2883            for (pn, _) in self.spaces[space]
-2884                .for_path(path)
-2885                .sent_packets
-2886                .iter_range(range)
-2887            {
-2888                newly_acked.insert_one(pn);
-2889            }
-2890        }
-2891
-2892        if newly_acked.is_empty() {
-2893            return Ok(());
-2894        }
-2895
-2896        let mut ack_eliciting_acked = false;
-2897        for packet in newly_acked.elts() {
-2898            if let Some(info) = self.spaces[space].for_path(path).take(packet) {
-2899                for (acked_path_id, acked_pn) in info.largest_acked.iter() {
-2900                    // Assume ACKs for all packets below the largest acknowledged in
-2901                    // `packet` have been received. This can cause the peer to spuriously
-2902                    // retransmit if some of our earlier ACKs were lost, but allows for
-2903                    // simpler state tracking. See discussion at
-2904                    // https://www.rfc-editor.org/rfc/rfc9000.html#name-limiting-ranges-by-tracking
-2905                    if let Some(pns) = self.spaces[space].path_space_mut(*acked_path_id) {
-2906                        pns.pending_acks.subtract_below(*acked_pn);
-2907                    }
-2908                }
-2909                ack_eliciting_acked |= info.ack_eliciting;
-2910
-2911                // Notify MTU discovery that a packet was acked, because it might be an MTU probe
-2912                let path_data = self.path_data_mut(path);
-2913                let mtu_updated = path_data.mtud.on_acked(space.kind(), packet, info.size);
-2914                if mtu_updated {
-2915                    path_data
-2916                        .congestion
-2917                        .on_mtu_update(path_data.mtud.current_mtu());
-2918                }
-2919
-2920                // Notify ack frequency that a packet was acked, because it might contain an ACK_FREQUENCY frame
-2921                self.ack_frequency.on_acked(path, packet);
-2922
-2923                self.on_packet_acked(now, path, packet, info);
-2924            }
-2925        }
+2879        if self.detect_spurious_loss(&ack, space, path) {
+2880            self.path_stats.for_path(path).spurious_congestion_events += 1;
+2881            self.path_data_mut(path)
+2882                .congestion
+2883                .on_spurious_congestion_event();
+2884        }
+2885
+2886        // Avoid DoS from unreasonably huge ack ranges by filtering out just the new acks.
+2887        let mut newly_acked = ArrayRangeSet::new();
+2888        for range in ack.iter() {
+2889            self.spaces[space].for_path(path).check_ack(range.clone())?;
+2890            for (pn, _) in self.spaces[space]
+2891                .for_path(path)
+2892                .sent_packets
+2893                .iter_range(range)
+2894            {
+2895                newly_acked.insert_one(pn);
+2896            }
+2897        }
+2898
+2899        if newly_acked.is_empty() {
+2900            return Ok(());
+2901        }
+2902
+2903        let mut ack_eliciting_acked = false;
+2904        for packet in newly_acked.elts() {
+2905            if let Some(info) = self.spaces[space].for_path(path).take(packet) {
+2906                for (acked_path_id, acked_pn) in info.largest_acked.iter() {
+2907                    // Assume ACKs for all packets below the largest acknowledged in
+2908                    // `packet` have been received. This can cause the peer to spuriously
+2909                    // retransmit if some of our earlier ACKs were lost, but allows for
+2910                    // simpler state tracking. See discussion at
+2911                    // https://www.rfc-editor.org/rfc/rfc9000.html#name-limiting-ranges-by-tracking
+2912                    if let Some(pns) = self.spaces[space].path_space_mut(*acked_path_id) {
+2913                        pns.pending_acks.subtract_below(*acked_pn);
+2914                    }
+2915                }
+2916                ack_eliciting_acked |= info.ack_eliciting;
+2917
+2918                // Notify MTU discovery that a packet was acked, because it might be an MTU probe
+2919                let path_data = self.path_data_mut(path);
+2920                let mtu_updated = path_data.mtud.on_acked(space.kind(), packet, info.size);
+2921                if mtu_updated {
+2922                    path_data
+2923                        .congestion
+2924                        .on_mtu_update(path_data.mtud.current_mtu());
+2925                }
 2926
-2927        let largest_ackd = self.spaces[space].for_path(path).largest_acked_packet_pn;
-2928        let path_data = self.path_data_mut(path);
-2929        let app_limited = path_data.app_limited;
-2930        let in_flight = path_data.in_flight.bytes;
-2931
-2932        path_data
-2933            .congestion
-2934            .on_end_acks(now, in_flight, app_limited, largest_ackd);
-2935
-2936        if new_largest_pn.is_some() && ack_eliciting_acked {
-2937            let ack_delay = if space != SpaceId::Data {
-2938                Duration::from_micros(0)
-2939            } else {
-2940                cmp::min(
-2941                    self.ack_frequency.peer_max_ack_delay,
-2942                    Duration::from_micros(ack.delay << self.peer_params.ack_delay_exponent.0),
-2943                )
-2944            };
-2945            let rtt = now.saturating_duration_since(
-2946                self.spaces[space]
-2947                    .for_path(path)
-2948                    .largest_acked_packet_send_time,
-2949            );
-2950
-2951            let next_pn = self.spaces[space].for_path(path).next_packet_number;
-2952            let path_data = self.path_data_mut(path);
-2953            // TODO(@divma): should be a method of path, should be contained in a single place
-2954            path_data.rtt.update(ack_delay, rtt);
-2955            if path_data.first_packet_after_rtt_sample.is_none() {
-2956                path_data.first_packet_after_rtt_sample = Some((space.kind(), next_pn));
-2957            }
-2958        }
-2959
-2960        // Must be called before crypto/pto_count are clobbered
-2961        self.detect_lost_packets(now, space, path, true);
-2962
-2963        // If the peer did not complete the handshake address validation the ACK could be
-2964        // spoofed, e.g. in the Initial space. Setting the pto_count back to 0 removes the
-2965        // exponential backoff from the PTO timer and would result in too many tail-loss
-2966        // probes being sent.
-2967        if self.peer_completed_handshake_address_validation() {
-2968            self.path_data_mut(path).pto_count = 0;
-2969        }
-2970
-2971        // Explicit congestion notification
-2972        // TODO(@divma): this code is a good example of logic that should be contained in a single
-2973        // place but it's split between the path data and the packet number space data, we should
-2974        // find a way to make this work without two lookups
-2975        if self.path_data(path).sending_ecn {
-2976            if let Some(ecn) = ack.ecn {
-2977                // We only examine ECN counters from ACKs that we are certain we received in transmit
-2978                // order, allowing us to compute an increase in ECN counts to compare against the number
-2979                // of newly acked packets that remains well-defined in the presence of arbitrary packet
-2980                // reordering.
-2981                if let Some(largest_sent_pn) = new_largest_pn {
-2982                    let sent = self.spaces[space]
-2983                        .for_path(path)
-2984                        .largest_acked_packet_send_time;
-2985                    self.process_ecn(
-2986                        now,
-2987                        space,
-2988                        path,
-2989                        newly_acked.len() as u64,
-2990                        ecn,
-2991                        sent,
-2992                        largest_sent_pn,
-2993                    );
-2994                }
-2995            } else {
-2996                // We always start out sending ECN, so any ack that doesn't acknowledge it disables it.
-2997                debug!("ECN not acknowledged by peer");
-2998                self.path_data_mut(path).sending_ecn = false;
-2999            }
-3000        }
-3001
-3002        self.set_loss_detection_timer(now, path);
-3003        Ok(())
-3004    }
-3005
-3006    fn detect_spurious_loss(&mut self, ack: &frame::Ack, space: SpaceId, path: PathId) -> bool {
-3007        let lost_packets = &mut self.spaces[space].for_path(path).lost_packets;
+2927                // Notify ack frequency that a packet was acked, because it might contain an ACK_FREQUENCY frame
+2928                self.ack_frequency.on_acked(path, packet);
+2929
+2930                self.on_packet_acked(now, path, packet, info);
+2931            }
+2932        }
+2933
+2934        let largest_ackd = self.spaces[space].for_path(path).largest_acked_packet_pn;
+2935        let path_data = self.path_data_mut(path);
+2936        let app_limited = path_data.app_limited;
+2937        let in_flight = path_data.in_flight.bytes;
+2938
+2939        path_data
+2940            .congestion
+2941            .on_end_acks(now, in_flight, app_limited, largest_ackd);
+2942
+2943        if new_largest_pn.is_some() && ack_eliciting_acked {
+2944            let ack_delay = if space != SpaceId::Data {
+2945                Duration::from_micros(0)
+2946            } else {
+2947                cmp::min(
+2948                    self.ack_frequency.peer_max_ack_delay,
+2949                    Duration::from_micros(ack.delay << self.peer_params.ack_delay_exponent.0),
+2950                )
+2951            };
+2952            let rtt = now.saturating_duration_since(
+2953                self.spaces[space]
+2954                    .for_path(path)
+2955                    .largest_acked_packet_send_time,
+2956            );
+2957
+2958            let next_pn = self.spaces[space].for_path(path).next_packet_number;
+2959            let path_data = self.path_data_mut(path);
+2960            // TODO(@divma): should be a method of path, should be contained in a single place
+2961            path_data.rtt.update(ack_delay, rtt);
+2962            if path_data.first_packet_after_rtt_sample.is_none() {
+2963                path_data.first_packet_after_rtt_sample = Some((space.kind(), next_pn));
+2964            }
+2965        }
+2966
+2967        // Must be called before crypto/pto_count are clobbered
+2968        self.detect_lost_packets(now, space, path, true);
+2969
+2970        // If the peer did not complete the handshake address validation the ACK could be
+2971        // spoofed, e.g. in the Initial space. Setting the pto_count back to 0 removes the
+2972        // exponential backoff from the PTO timer and would result in too many tail-loss
+2973        // probes being sent.
+2974        if self.peer_completed_handshake_address_validation() {
+2975            self.path_data_mut(path).pto_count = 0;
+2976        }
+2977
+2978        // Explicit congestion notification
+2979        // TODO(@divma): this code is a good example of logic that should be contained in a single
+2980        // place but it's split between the path data and the packet number space data, we should
+2981        // find a way to make this work without two lookups
+2982        if self.path_data(path).sending_ecn {
+2983            if let Some(ecn) = ack.ecn {
+2984                // We only examine ECN counters from ACKs that we are certain we received in transmit
+2985                // order, allowing us to compute an increase in ECN counts to compare against the number
+2986                // of newly acked packets that remains well-defined in the presence of arbitrary packet
+2987                // reordering.
+2988                if let Some(largest_sent_pn) = new_largest_pn {
+2989                    let sent = self.spaces[space]
+2990                        .for_path(path)
+2991                        .largest_acked_packet_send_time;
+2992                    self.process_ecn(
+2993                        now,
+2994                        space,
+2995                        path,
+2996                        newly_acked.len() as u64,
+2997                        ecn,
+2998                        sent,
+2999                        largest_sent_pn,
+3000                    );
+3001                }
+3002            } else {
+3003                // We always start out sending ECN, so any ack that doesn't acknowledge it disables it.
+3004                debug!("ECN not acknowledged by peer");
+3005                self.path_data_mut(path).sending_ecn = false;
+3006            }
+3007        }
 3008
-3009        if lost_packets.is_empty() {
-3010            return false;
-3011        }
+3009        self.set_loss_detection_timer(now, path);
+3010        Ok(())
+3011    }
 3012
-3013        for range in ack.iter() {
-3014            let spurious_losses: Vec<u64> = lost_packets
-3015                .iter_range(range.clone())
-3016                .map(|(pn, _info)| pn)
-3017                .collect();
-3018
-3019            for pn in spurious_losses {
-3020                lost_packets.remove(pn);
-3021            }
-3022        }
-3023
-3024        // If this ACK frame acknowledged all deemed lost packets,
-3025        // then we have raised a spurious congestion event in the past.
-3026        // We cannot conclude when there are remaining packets,
-3027        // but future ACK frames might indicate a spurious loss detection.
-3028        lost_packets.is_empty()
-3029    }
+3013    fn detect_spurious_loss(&mut self, ack: &frame::Ack, space: SpaceId, path: PathId) -> bool {
+3014        let lost_packets = &mut self.spaces[space].for_path(path).lost_packets;
+3015
+3016        if lost_packets.is_empty() {
+3017            return false;
+3018        }
+3019
+3020        for range in ack.iter() {
+3021            let spurious_losses: Vec<u64> = lost_packets
+3022                .iter_range(range.clone())
+3023                .map(|(pn, _info)| pn)
+3024                .collect();
+3025
+3026            for pn in spurious_losses {
+3027                lost_packets.remove(pn);
+3028            }
+3029        }
 3030
-3031    /// Drain lost packets that we reasonably think will never arrive
-3032    ///
-3033    /// The current criterion is copied from `msquic`:
-3034    /// discard packets that were sent earlier than 2 probe timeouts ago.
-3035    fn drain_lost_packets(&mut self, now: Instant, space: SpaceId, path: PathId) {
-3036        let two_pto = 2 * self.path_data(path).rtt.pto_base();
+3031        // If this ACK frame acknowledged all deemed lost packets,
+3032        // then we have raised a spurious congestion event in the past.
+3033        // We cannot conclude when there are remaining packets,
+3034        // but future ACK frames might indicate a spurious loss detection.
+3035        lost_packets.is_empty()
+3036    }
 3037
-3038        let lost_packets = &mut self.spaces[space].for_path(path).lost_packets;
-3039        lost_packets.retain(|_pn, info| now.saturating_duration_since(info.time_sent) <= two_pto);
-3040    }
-3041
-3042    /// Process a new ECN block from an in-order ACK
-3043    fn process_ecn(
-3044        &mut self,
-3045        now: Instant,
-3046        space: SpaceId,
-3047        path: PathId,
-3048        newly_acked_pn: u64,
-3049        ecn: frame::EcnCounts,
-3050        largest_sent_time: Instant,
-3051        largest_sent_pn: u64,
-3052    ) {
-3053        match self.spaces[space]
-3054            .for_path(path)
-3055            .detect_ecn(newly_acked_pn, ecn)
-3056        {
-3057            Err(e) => {
-3058                debug!("halting ECN due to verification failure: {}", e);
-3059
-3060                self.path_data_mut(path).sending_ecn = false;
-3061                // Wipe out the existing value because it might be garbage and could interfere with
-3062                // future attempts to use ECN on new paths.
-3063                self.spaces[space].for_path(path).ecn_feedback = frame::EcnCounts::ZERO;
-3064            }
-3065            Ok(false) => {}
-3066            Ok(true) => {
-3067                self.path_stats.for_path(path).congestion_events += 1;
-3068                self.path_data_mut(path).congestion.on_congestion_event(
-3069                    now,
-3070                    largest_sent_time,
-3071                    false,
-3072                    true,
-3073                    0,
-3074                    largest_sent_pn,
-3075                );
-3076            }
-3077        }
-3078    }
-3079
-3080    // Not timing-aware, so it's safe to call this for inferred acks, such as arise from
-3081    // high-latency handshakes
-3082    fn on_packet_acked(&mut self, now: Instant, path_id: PathId, pn: u64, info: SentPacket) {
-3083        let path = self.path_data_mut(path_id);
-3084        let app_limited = path.app_limited;
-3085        path.remove_in_flight(&info);
-3086        if info.ack_eliciting && info.path_generation == path.generation() {
-3087            // Only pass ACKs to the congestion controller if it belongs to this exact
-3088            // generation of the path. Otherwise we might be feeding ACKs from the previous
-3089            // 4-tuple into our congestion controller.
-3090            let rtt = path.rtt;
-3091            path.congestion
-3092                .on_ack(now, info.time_sent, info.size.into(), pn, app_limited, &rtt);
-3093        }
-3094
-3095        // Update state for confirmed delivery of frames
-3096        if let Some(retransmits) = info.retransmits.get() {
-3097            for (id, _) in retransmits.reset_stream.iter() {
-3098                self.streams.reset_acked(*id);
-3099            }
+3038    /// Drain lost packets that we reasonably think will never arrive
+3039    ///
+3040    /// The current criterion is copied from `msquic`:
+3041    /// discard packets that were sent earlier than 2 probe timeouts ago.
+3042    fn drain_lost_packets(&mut self, now: Instant, space: SpaceId, path: PathId) {
+3043        let two_pto = 2 * self.path_data(path).rtt.pto_base();
+3044
+3045        let lost_packets = &mut self.spaces[space].for_path(path).lost_packets;
+3046        lost_packets.retain(|_pn, info| now.saturating_duration_since(info.time_sent) <= two_pto);
+3047    }
+3048
+3049    /// Process a new ECN block from an in-order ACK
+3050    fn process_ecn(
+3051        &mut self,
+3052        now: Instant,
+3053        space: SpaceId,
+3054        path: PathId,
+3055        newly_acked_pn: u64,
+3056        ecn: frame::EcnCounts,
+3057        largest_sent_time: Instant,
+3058        largest_sent_pn: u64,
+3059    ) {
+3060        match self.spaces[space]
+3061            .for_path(path)
+3062            .detect_ecn(newly_acked_pn, ecn)
+3063        {
+3064            Err(e) => {
+3065                debug!("halting ECN due to verification failure: {}", e);
+3066
+3067                self.path_data_mut(path).sending_ecn = false;
+3068                // Wipe out the existing value because it might be garbage and could interfere with
+3069                // future attempts to use ECN on new paths.
+3070                self.spaces[space].for_path(path).ecn_feedback = frame::EcnCounts::ZERO;
+3071            }
+3072            Ok(false) => {}
+3073            Ok(true) => {
+3074                self.path_stats.for_path(path).congestion_events += 1;
+3075                self.path_data_mut(path).congestion.on_congestion_event(
+3076                    now,
+3077                    largest_sent_time,
+3078                    false,
+3079                    true,
+3080                    0,
+3081                    largest_sent_pn,
+3082                );
+3083            }
+3084        }
+3085    }
+3086
+3087    // Not timing-aware, so it's safe to call this for inferred acks, such as arise from
+3088    // high-latency handshakes
+3089    fn on_packet_acked(&mut self, now: Instant, path_id: PathId, pn: u64, info: SentPacket) {
+3090        let path = self.path_data_mut(path_id);
+3091        let app_limited = path.app_limited;
+3092        path.remove_in_flight(&info);
+3093        if info.ack_eliciting && info.path_generation == path.generation() {
+3094            // Only pass ACKs to the congestion controller if it belongs to this exact
+3095            // generation of the path. Otherwise we might be feeding ACKs from the previous
+3096            // 4-tuple into our congestion controller.
+3097            let rtt = path.rtt;
+3098            path.congestion
+3099                .on_ack(now, info.time_sent, info.size.into(), pn, app_limited, &rtt);
 3100        }
 3101
-3102        for frame in info.stream_frames {
-3103            self.streams.received_ack_of(frame);
-3104        }
-3105    }
-3106
-3107    fn set_key_discard_timer(&mut self, now: Instant, space: SpaceKind) {
-3108        let start = if self.crypto_state.has_keys(EncryptionLevel::ZeroRtt) {
-3109            now
-3110        } else {
-3111            self.crypto_state
-3112                .prev_crypto
-3113                .as_ref()
-3114                .expect("no previous keys")
-3115                .end_packet
-3116                .as_ref()
-3117                .expect("update not acknowledged yet")
-3118                .1
-3119        };
-3120
-3121        // QUIC-MULTIPATH § 2.5 Key Phase Update Process: use largest PTO of all paths.
-3122        self.timers.set(
-3123            Timer::Conn(ConnTimer::KeyDiscard),
-3124            start + self.max_pto_for_space(space) * 3,
-3125            self.qlog.with_time(now),
-3126        );
-3127    }
-3128
-3129    /// Handle a [`PathTimer::LossDetection`] timeout.
-3130    ///
-3131    /// This timer expires for two reasons:
-3132    /// - An ACK-eliciting packet we sent should be considered lost.
-3133    /// - The PTO may have expired and a tail-loss probe needs to be scheduled.
-3134    ///
-3135    /// The former needs us to schedule re-transmission of the lost data.
-3136    ///
-3137    /// The latter means we have not received an ACK for an ack-eliciting packet we sent
-3138    /// within the PTO time-window. We need to schedule a tail-loss probe, an ack-eliciting
-3139    /// packet, to try and elicit new acknowledgements. These new acknowledgements will
-3140    /// indicate whether the previously sent packets were lost or not.
-3141    fn on_loss_detection_timeout(&mut self, now: Instant, path_id: PathId) {
-3142        if let Some((_, pn_space)) = self.loss_time_and_space(path_id) {
-3143            // Time threshold loss Detection
-3144            self.detect_lost_packets(now, pn_space, path_id, false);
-3145            self.set_loss_detection_timer(now, path_id);
-3146            return;
-3147        }
-3148
-3149        let Some((_, space)) = self.pto_time_and_space(now, path_id) else {
-3150            error!(%path_id, "PTO expired while unset");
-3151            return;
-3152        };
-3153        trace!(
-3154            in_flight = self.path_data(path_id).in_flight.bytes,
-3155            count = self.path_data(path_id).pto_count,
-3156            ?space,
-3157            %path_id,
-3158            "PTO fired"
-3159        );
-3160
-3161        let count = match self.path_data(path_id).in_flight.ack_eliciting {
-3162            // A PTO when we're not expecting any ACKs must be due to handshake
-3163            // anti-amplification deadlock prevention.
-3164            0 => {
-3165                debug_assert!(!self.peer_completed_handshake_address_validation());
-3166                1
-3167            }
-3168            // Conventional loss probe
-3169            _ => 2,
-3170        };
-3171        let pns = self.spaces[space].for_path(path_id);
-3172        pns.loss_probes = pns.loss_probes.saturating_add(count);
-3173        let path_data = self.path_data_mut(path_id);
-3174        path_data.pto_count = path_data.pto_count.saturating_add(1);
-3175        self.set_loss_detection_timer(now, path_id);
-3176    }
-3177
-3178    /// Detect any lost packets
-3179    ///
-3180    /// There are two cases in which we detects lost packets:
-3181    ///
-3182    /// - We received an ACK packet.
-3183    /// - The [`PathTimer::LossDetection`] timer expired. So there is an un-acknowledged packet
-3184    ///   that was followed by an acknowledged packet. The loss timer for this
-3185    ///   un-acknowledged packet expired and we need to detect that packet as lost.
+3102        // Update state for confirmed delivery of frames
+3103        if let Some(retransmits) = info.retransmits.get() {
+3104            for (id, _) in retransmits.reset_stream.iter() {
+3105                self.streams.reset_acked(*id);
+3106            }
+3107        }
+3108
+3109        for frame in info.stream_frames {
+3110            self.streams.received_ack_of(frame);
+3111        }
+3112    }
+3113
+3114    fn set_key_discard_timer(&mut self, now: Instant, space: SpaceKind) {
+3115        let start = if self.crypto_state.has_keys(EncryptionLevel::ZeroRtt) {
+3116            now
+3117        } else {
+3118            self.crypto_state
+3119                .prev_crypto
+3120                .as_ref()
+3121                .expect("no previous keys")
+3122                .end_packet
+3123                .as_ref()
+3124                .expect("update not acknowledged yet")
+3125                .1
+3126        };
+3127
+3128        // QUIC-MULTIPATH § 2.5 Key Phase Update Process: use largest PTO of all paths.
+3129        self.timers.set(
+3130            Timer::Conn(ConnTimer::KeyDiscard),
+3131            start + self.max_pto_for_space(space) * 3,
+3132            self.qlog.with_time(now),
+3133        );
+3134    }
+3135
+3136    /// Handle a [`PathTimer::LossDetection`] timeout.
+3137    ///
+3138    /// This timer expires for two reasons:
+3139    /// - An ACK-eliciting packet we sent should be considered lost.
+3140    /// - The PTO may have expired and a tail-loss probe needs to be scheduled.
+3141    ///
+3142    /// The former needs us to schedule re-transmission of the lost data.
+3143    ///
+3144    /// The latter means we have not received an ACK for an ack-eliciting packet we sent
+3145    /// within the PTO time-window. We need to schedule a tail-loss probe, an ack-eliciting
+3146    /// packet, to try and elicit new acknowledgements. These new acknowledgements will
+3147    /// indicate whether the previously sent packets were lost or not.
+3148    fn on_loss_detection_timeout(&mut self, now: Instant, path_id: PathId) {
+3149        if let Some((_, pn_space)) = self.loss_time_and_space(path_id) {
+3150            // Time threshold loss Detection
+3151            self.detect_lost_packets(now, pn_space, path_id, false);
+3152            self.set_loss_detection_timer(now, path_id);
+3153            return;
+3154        }
+3155
+3156        let Some((_, space)) = self.pto_time_and_space(now, path_id) else {
+3157            error!(%path_id, "PTO expired while unset");
+3158            return;
+3159        };
+3160        trace!(
+3161            in_flight = self.path_data(path_id).in_flight.bytes,
+3162            count = self.path_data(path_id).pto_count,
+3163            ?space,
+3164            %path_id,
+3165            "PTO fired"
+3166        );
+3167
+3168        let count = match self.path_data(path_id).in_flight.ack_eliciting {
+3169            // A PTO when we're not expecting any ACKs must be due to handshake
+3170            // anti-amplification deadlock prevention.
+3171            0 => {
+3172                debug_assert!(!self.peer_completed_handshake_address_validation());
+3173                1
+3174            }
+3175            // Conventional loss probe
+3176            _ => 2,
+3177        };
+3178        let pns = self.spaces[space].for_path(path_id);
+3179        pns.loss_probes = pns.loss_probes.saturating_add(count);
+3180        let path_data = self.path_data_mut(path_id);
+3181        path_data.pto_count = path_data.pto_count.saturating_add(1);
+3182        self.set_loss_detection_timer(now, path_id);
+3183    }
+3184
+3185    /// Detect any lost packets
 3186    ///
-3187    /// Packets are lost if they are both (See RFC9002 §6.1):
+3187    /// There are two cases in which we detects lost packets:
 3188    ///
-3189    /// - Unacknowledged, in flight and sent prior to an acknowledged packet.
-3190    /// - Old enough by either:
-3191    ///   - Having a packet number [`TransportConfig::packet_threshold`] lower then the last
-3192    ///     acknowledged packet.
-3193    ///   - Being sent [`TransportConfig::time_threshold`] * RTT in the past.
-3194    fn detect_lost_packets(
-3195        &mut self,
-3196        now: Instant,
-3197        pn_space: SpaceId,
-3198        path_id: PathId,
-3199        due_to_ack: bool,
-3200    ) {
-3201        let mut lost_packets = Vec::<u64>::new();
-3202        let mut lost_mtu_probe = None;
-3203        let mut in_persistent_congestion = false;
-3204        let mut size_of_lost_packets = 0u64;
-3205        self.spaces[pn_space].for_path(path_id).loss_time = None;
-3206
-3207        // Find all the lost packets, populating all variables initialised above.
-3208
-3209        let path = self.path_data(path_id);
-3210        let in_flight_mtu_probe = path.mtud.in_flight_mtu_probe();
-3211        let loss_delay = path
-3212            .rtt
-3213            .conservative()
-3214            .mul_f32(self.config.time_threshold)
-3215            .max(TIMER_GRANULARITY);
-3216        let first_packet_after_rtt_sample = path.first_packet_after_rtt_sample;
-3217
-3218        let largest_acked_packet_pn = self.spaces[pn_space]
-3219            .for_path(path_id)
-3220            .largest_acked_packet_pn
-3221            .expect("detect_lost_packets only to be called if path received at least one ACK");
-3222        let packet_threshold = self.config.packet_threshold as u64;
-3223
-3224        // InPersistentCongestion: Determine if all packets in the time period before the newest
-3225        // lost packet, including the edges, are marked lost. PTO computation must always
-3226        // include max ACK delay, i.e. operate as if in Data space (see RFC9001 §7.6.1).
-3227        let congestion_period = self
-3228            .pto(SpaceKind::Data, path_id)
-3229            .saturating_mul(self.config.persistent_congestion_threshold);
-3230        let mut persistent_congestion_start: Option<Instant> = None;
-3231        let mut prev_packet = None;
-3232        let space = self.spaces[pn_space].for_path(path_id);
-3233
-3234        for (packet, info) in space.sent_packets.iter_range(0..largest_acked_packet_pn) {
-3235            if prev_packet != Some(packet.wrapping_sub(1)) {
-3236                // An intervening packet was acknowledged
-3237                persistent_congestion_start = None;
-3238            }
-3239
-3240            // Packets sent before now - loss_delay are deemed lost.
-3241            // However, we avoid subtraction as it can panic and there's no
-3242            // saturating equivalent of this subtraction operation with a Duration.
-3243            let packet_too_old = now.saturating_duration_since(info.time_sent) >= loss_delay;
-3244            if packet_too_old || largest_acked_packet_pn >= packet + packet_threshold {
-3245                // The packet should be declared lost.
-3246                if Some(packet) == in_flight_mtu_probe {
-3247                    // Lost MTU probes are not included in `lost_packets`, because they
-3248                    // should not trigger a congestion control response
-3249                    lost_mtu_probe = in_flight_mtu_probe;
-3250                } else {
-3251                    lost_packets.push(packet);
-3252                    size_of_lost_packets += info.size as u64;
-3253                    if info.ack_eliciting && due_to_ack {
-3254                        match persistent_congestion_start {
-3255                            // Two ACK-eliciting packets lost more than
-3256                            // congestion_period apart, with no ACKed packets in between
-3257                            Some(start) if info.time_sent - start > congestion_period => {
-3258                                in_persistent_congestion = true;
-3259                            }
-3260                            // Persistent congestion must start after the first RTT sample
-3261                            None if first_packet_after_rtt_sample
-3262                                .is_some_and(|x| x < (pn_space.kind(), packet)) =>
-3263                            {
-3264                                persistent_congestion_start = Some(info.time_sent);
-3265                            }
-3266                            _ => {}
-3267                        }
-3268                    }
-3269                }
-3270            } else {
-3271                // The packet should not yet be declared lost.
-3272                if space.loss_time.is_none() {
-3273                    // Since we iterate in order the lowest packet number's loss time will
-3274                    // always be the earliest.
-3275                    space.loss_time = Some(info.time_sent + loss_delay);
+3189    /// - We received an ACK packet.
+3190    /// - The [`PathTimer::LossDetection`] timer expired. So there is an un-acknowledged packet
+3191    ///   that was followed by an acknowledged packet. The loss timer for this
+3192    ///   un-acknowledged packet expired and we need to detect that packet as lost.
+3193    ///
+3194    /// Packets are lost if they are both (See RFC9002 §6.1):
+3195    ///
+3196    /// - Unacknowledged, in flight and sent prior to an acknowledged packet.
+3197    /// - Old enough by either:
+3198    ///   - Having a packet number [`TransportConfig::packet_threshold`] lower then the last
+3199    ///     acknowledged packet.
+3200    ///   - Being sent [`TransportConfig::time_threshold`] * RTT in the past.
+3201    fn detect_lost_packets(
+3202        &mut self,
+3203        now: Instant,
+3204        pn_space: SpaceId,
+3205        path_id: PathId,
+3206        due_to_ack: bool,
+3207    ) {
+3208        let mut lost_packets = Vec::<u64>::new();
+3209        let mut lost_mtu_probe = None;
+3210        let mut in_persistent_congestion = false;
+3211        let mut size_of_lost_packets = 0u64;
+3212        self.spaces[pn_space].for_path(path_id).loss_time = None;
+3213
+3214        // Find all the lost packets, populating all variables initialised above.
+3215
+3216        let path = self.path_data(path_id);
+3217        let in_flight_mtu_probe = path.mtud.in_flight_mtu_probe();
+3218        let loss_delay = path
+3219            .rtt
+3220            .conservative()
+3221            .mul_f32(self.config.time_threshold)
+3222            .max(TIMER_GRANULARITY);
+3223        let first_packet_after_rtt_sample = path.first_packet_after_rtt_sample;
+3224
+3225        let largest_acked_packet_pn = self.spaces[pn_space]
+3226            .for_path(path_id)
+3227            .largest_acked_packet_pn
+3228            .expect("detect_lost_packets only to be called if path received at least one ACK");
+3229        let packet_threshold = self.config.packet_threshold as u64;
+3230
+3231        // InPersistentCongestion: Determine if all packets in the time period before the newest
+3232        // lost packet, including the edges, are marked lost. PTO computation must always
+3233        // include max ACK delay, i.e. operate as if in Data space (see RFC9001 §7.6.1).
+3234        let congestion_period = self
+3235            .pto(SpaceKind::Data, path_id)
+3236            .saturating_mul(self.config.persistent_congestion_threshold);
+3237        let mut persistent_congestion_start: Option<Instant> = None;
+3238        let mut prev_packet = None;
+3239        let space = self.spaces[pn_space].for_path(path_id);
+3240
+3241        for (packet, info) in space.sent_packets.iter_range(0..largest_acked_packet_pn) {
+3242            if prev_packet != Some(packet.wrapping_sub(1)) {
+3243                // An intervening packet was acknowledged
+3244                persistent_congestion_start = None;
+3245            }
+3246
+3247            // Packets sent before now - loss_delay are deemed lost.
+3248            // However, we avoid subtraction as it can panic and there's no
+3249            // saturating equivalent of this subtraction operation with a Duration.
+3250            let packet_too_old = now.saturating_duration_since(info.time_sent) >= loss_delay;
+3251            if packet_too_old || largest_acked_packet_pn >= packet + packet_threshold {
+3252                // The packet should be declared lost.
+3253                if Some(packet) == in_flight_mtu_probe {
+3254                    // Lost MTU probes are not included in `lost_packets`, because they
+3255                    // should not trigger a congestion control response
+3256                    lost_mtu_probe = in_flight_mtu_probe;
+3257                } else {
+3258                    lost_packets.push(packet);
+3259                    size_of_lost_packets += info.size as u64;
+3260                    if info.ack_eliciting && due_to_ack {
+3261                        match persistent_congestion_start {
+3262                            // Two ACK-eliciting packets lost more than
+3263                            // congestion_period apart, with no ACKed packets in between
+3264                            Some(start) if info.time_sent - start > congestion_period => {
+3265                                in_persistent_congestion = true;
+3266                            }
+3267                            // Persistent congestion must start after the first RTT sample
+3268                            None if first_packet_after_rtt_sample
+3269                                .is_some_and(|x| x < (pn_space.kind(), packet)) =>
+3270                            {
+3271                                persistent_congestion_start = Some(info.time_sent);
+3272                            }
+3273                            _ => {}
+3274                        }
+3275                    }
 3276                }
-3277                persistent_congestion_start = None;
-3278            }
-3279
-3280            prev_packet = Some(packet);
-3281        }
-3282
-3283        self.handle_lost_packets(
-3284            pn_space,
-3285            path_id,
-3286            now,
-3287            lost_packets,
-3288            lost_mtu_probe,
-3289            loss_delay,
-3290            in_persistent_congestion,
-3291            size_of_lost_packets,
-3292        );
-3293    }
-3294
-3295    /// Drops the path state, declaring any remaining in-flight packets as lost
-3296    fn discard_path(&mut self, path_id: PathId, now: Instant) {
-3297        trace!(%path_id, "dropping path state");
-3298        let path = self.path_data(path_id);
-3299        let in_flight_mtu_probe = path.mtud.in_flight_mtu_probe();
-3300
-3301        let mut size_of_lost_packets = 0u64; // add to path_stats.lost_bytes;
-3302        let lost_pns: Vec<_> = self.spaces[SpaceId::Data]
-3303            .for_path(path_id)
-3304            .sent_packets
-3305            .iter()
-3306            .filter(|(pn, _info)| Some(*pn) != in_flight_mtu_probe)
-3307            .map(|(pn, info)| {
-3308                size_of_lost_packets += info.size as u64;
-3309                pn
-3310            })
-3311            .collect();
-3312
-3313        if !lost_pns.is_empty() {
-3314            trace!(
-3315                %path_id,
-3316                count = lost_pns.len(),
-3317                lost_bytes = size_of_lost_packets,
-3318                "packets lost on path abandon"
-3319            );
-3320            self.handle_lost_packets(
-3321                SpaceId::Data,
-3322                path_id,
-3323                now,
-3324                lost_pns,
-3325                in_flight_mtu_probe,
-3326                Duration::ZERO,
-3327                false,
-3328                size_of_lost_packets,
-3329            );
-3330        }
-3331        // Before removing the path, we fetch the final path stats via `Self::path_stats`.
-3332        // This updates some values for the last time.
-3333        let path_stats = self.path_stats.discard(&path_id);
-3334        self.partial_stats += path_stats;
-3335        self.paths.remove(&path_id);
-3336        self.spaces[SpaceId::Data].number_spaces.remove(&path_id);
-3337
-3338        self.events.push_back(
-3339            PathEvent::Discarded {
-3340                id: path_id,
-3341                path_stats: Box::new(path_stats),
-3342            }
-3343            .into(),
-3344        );
-3345    }
-3346
-3347    fn handle_lost_packets(
-3348        &mut self,
-3349        pn_space: SpaceId,
-3350        path_id: PathId,
-3351        now: Instant,
-3352        lost_packets: Vec<u64>,
-3353        lost_mtu_probe: Option<u64>,
-3354        loss_delay: Duration,
-3355        in_persistent_congestion: bool,
-3356        size_of_lost_packets: u64,
-3357    ) {
-3358        debug_assert!(lost_packets.is_sorted(), "lost_packets must be sorted");
-3359
-3360        self.drain_lost_packets(now, pn_space, path_id);
-3361
-3362        // OnPacketsLost
-3363        if let Some(largest_lost) = lost_packets.last().cloned() {
-3364            let old_bytes_in_flight = self.path_data_mut(path_id).in_flight.bytes;
-3365            let largest_lost_sent = self.spaces[pn_space]
-3366                .for_path(path_id)
-3367                .sent_packets
-3368                .get(largest_lost)
-3369                .unwrap()
-3370                .time_sent;
-3371            let path_stats = self.path_stats.for_path(path_id);
-3372            path_stats.lost_packets += lost_packets.len() as u64;
-3373            path_stats.lost_bytes += size_of_lost_packets;
-3374            trace!(
-3375                %path_id,
-3376                count = lost_packets.len(),
-3377                lost_bytes = size_of_lost_packets,
-3378                "packets lost",
-3379            );
-3380
-3381            for &packet in &lost_packets {
-3382                let Some(info) = self.spaces[pn_space].for_path(path_id).take(packet) else {
-3383                    continue;
-3384                };
-3385                self.qlog
-3386                    .emit_packet_lost(packet, &info, loss_delay, pn_space.kind(), now);
-3387                self.paths
-3388                    .get_mut(&path_id)
-3389                    .unwrap()
-3390                    .remove_in_flight(&info);
-3391
-3392                for frame in info.stream_frames {
-3393                    self.streams.retransmit(frame);
-3394                }
-3395                self.spaces[pn_space].pending |= info.retransmits;
-3396                let path = self.path_data_mut(path_id);
-3397                path.mtud.on_non_probe_lost(packet, info.size);
-3398                path.congestion.on_packet_lost(info.size, packet, now);
-3399
-3400                self.spaces[pn_space].for_path(path_id).lost_packets.insert(
-3401                    packet,
-3402                    LostPacket {
-3403                        time_sent: info.time_sent,
-3404                    },
-3405                );
-3406            }
-3407
-3408            let path = self.path_data_mut(path_id);
-3409            if path.mtud.black_hole_detected(now) {
-3410                path.congestion.on_mtu_update(path.mtud.current_mtu());
-3411                if let Some(max_datagram_size) = self.datagrams().max_size()
-3412                    && self.datagrams.drop_oversized(max_datagram_size)
-3413                    && self.datagrams.send_blocked
-3414                {
-3415                    self.datagrams.send_blocked = false;
-3416                    self.events.push_back(Event::DatagramsUnblocked);
-3417                }
-3418                self.path_stats.for_path(path_id).black_holes_detected += 1;
-3419            }
-3420
-3421            // Don't apply congestion penalty for lost ack-only packets
-3422            let lost_ack_eliciting =
-3423                old_bytes_in_flight != self.path_data_mut(path_id).in_flight.bytes;
-3424
-3425            if lost_ack_eliciting {
-3426                self.path_stats.for_path(path_id).congestion_events += 1;
-3427                self.path_data_mut(path_id).congestion.on_congestion_event(
-3428                    now,
-3429                    largest_lost_sent,
-3430                    in_persistent_congestion,
-3431                    false,
-3432                    size_of_lost_packets,
-3433                    largest_lost,
-3434                );
-3435            }
-3436        }
-3437
-3438        // Handle a lost MTU probe
-3439        if let Some(packet) = lost_mtu_probe {
-3440            let info = self.spaces[SpaceId::Data]
-3441                .for_path(path_id)
-3442                .take(packet)
-3443                .unwrap(); // safe: lost_mtu_probe is omitted from lost_packets, and
-3444            // therefore must not have been removed yet
-3445            self.paths
-3446                .get_mut(&path_id)
-3447                .unwrap()
-3448                .remove_in_flight(&info);
-3449            self.path_data_mut(path_id).mtud.on_probe_lost();
-3450            self.path_stats.for_path(path_id).lost_plpmtud_probes += 1;
-3451        }
-3452    }
-3453
-3454    /// Returns the earliest time packets should be declared lost for all spaces on a path.
-3455    ///
-3456    /// If a path has an acknowledged packet with any prior un-acknowledged packets, the
-3457    /// earliest un-acknowledged packet can be declared lost after a timeout has elapsed.
-3458    /// The time returned is when this packet should be declared lost.
-3459    fn loss_time_and_space(&self, path_id: PathId) -> Option<(Instant, SpaceId)> {
-3460        SpaceId::iter()
-3461            .filter_map(|id| {
-3462                self.spaces[id]
-3463                    .number_spaces
-3464                    .get(&path_id)
-3465                    .and_then(|pns| pns.loss_time)
-3466                    .map(|time| (time, id))
-3467            })
-3468            .min_by_key(|&(time, _)| time)
-3469    }
-3470
-3471    /// Returns the earliest next PTO should fire for all spaces on a path.
-3472    ///
-3473    /// This needs to be fully deterministic because it is also used to determine the PTO
-3474    /// that fired, not just to set the next timer. So if it fired in the past it needs to
-3475    /// return the time from the past at which it fired.
-3476    ///
-3477    /// This is the next time a tail-loss probe should be sent.
-3478    fn pto_time_and_space(&mut self, now: Instant, path_id: PathId) -> Option<(Instant, SpaceId)> {
-3479        let path = self.path(path_id)?;
-3480        let pto_count = path.pto_count;
-3481
-3482        // Cap the maximum interval between two tail-loss probes.
-3483        let max_interval = if path.rtt.get() > SLOW_RTT_THRESHOLD {
-3484            // For slow links we want to increase the interval beyond 2s.
-3485            (path.rtt.get() * 3) / 2
-3486        } else if let Some(idle) = path.idle_timeout.or(self.idle_timeout)
-3487            && idle <= MIN_IDLE_FOR_FAST_PTO
-3488        {
-3489            // If the idle timeout is relatively low, cap at 1s so we get plenty of retries
-3490            // before the idle timeout fires.
-3491            MAX_PTO_FAST_INTERVAL
-3492        } else {
-3493            // Otherwise cap to 2s.
-3494            MAX_PTO_INTERVAL
-3495        };
-3496
-3497        if path_id == PathId::ZERO
-3498            && path.in_flight.ack_eliciting == 0
-3499            && !self.peer_completed_handshake_address_validation()
-3500        {
-3501            // Address Validation during Connection Establishment:
-3502            // https://www.rfc-editor.org/rfc/rfc9000.html#section-8.1. To prevent a
-3503            // deadlock if an Initial or Handshake packet from the server is lost and the
-3504            // server can not send more due to its anti-amplification limit the client must
-3505            // send another packet on PTO.
-3506            let space = match self.highest_space {
-3507                SpaceKind::Handshake => SpaceId::Handshake,
-3508                _ => SpaceId::Initial,
-3509            };
-3510
-3511            let backoff = 2u32.pow(path.pto_count.min(MAX_BACKOFF_EXPONENT));
-3512            let duration = path.rtt.pto_base() * backoff;
-3513            let duration = duration.min(max_interval);
-3514            return Some((now + duration, space));
-3515        }
-3516
-3517        let mut result = None;
-3518        for space in SpaceId::iter() {
-3519            let Some(pns) = self.spaces[space].number_spaces.get(&path_id) else {
-3520                continue;
-3521            };
-3522
-3523            if space == SpaceId::Data && !self.is_handshake_confirmed() {
-3524                // https://www.rfc-editor.org/rfc/rfc9002.html#section-6.2.1-7:
-3525                // An endpoint MUST NOT set its PTO timer for the Application Data packet
-3526                // number space until the handshake is confirmed.
-3527                continue;
-3528            }
+3277            } else {
+3278                // The packet should not yet be declared lost.
+3279                if space.loss_time.is_none() {
+3280                    // Since we iterate in order the lowest packet number's loss time will
+3281                    // always be the earliest.
+3282                    space.loss_time = Some(info.time_sent + loss_delay);
+3283                }
+3284                persistent_congestion_start = None;
+3285            }
+3286
+3287            prev_packet = Some(packet);
+3288        }
+3289
+3290        self.handle_lost_packets(
+3291            pn_space,
+3292            path_id,
+3293            now,
+3294            lost_packets,
+3295            lost_mtu_probe,
+3296            loss_delay,
+3297            in_persistent_congestion,
+3298            size_of_lost_packets,
+3299        );
+3300    }
+3301
+3302    /// Drops the path state, declaring any remaining in-flight packets as lost
+3303    fn discard_path(&mut self, path_id: PathId, now: Instant) {
+3304        trace!(%path_id, "dropping path state");
+3305        let path = self.path_data(path_id);
+3306        let in_flight_mtu_probe = path.mtud.in_flight_mtu_probe();
+3307
+3308        let mut size_of_lost_packets = 0u64; // add to path_stats.lost_bytes;
+3309        let lost_pns: Vec<_> = self.spaces[SpaceId::Data]
+3310            .for_path(path_id)
+3311            .sent_packets
+3312            .iter()
+3313            .filter(|(pn, _info)| Some(*pn) != in_flight_mtu_probe)
+3314            .map(|(pn, info)| {
+3315                size_of_lost_packets += info.size as u64;
+3316                pn
+3317            })
+3318            .collect();
+3319
+3320        if !lost_pns.is_empty() {
+3321            trace!(
+3322                %path_id,
+3323                count = lost_pns.len(),
+3324                lost_bytes = size_of_lost_packets,
+3325                "packets lost on path abandon"
+3326            );
+3327            self.handle_lost_packets(
+3328                SpaceId::Data,
+3329                path_id,
+3330                now,
+3331                lost_pns,
+3332                in_flight_mtu_probe,
+3333                Duration::ZERO,
+3334                false,
+3335                size_of_lost_packets,
+3336            );
+3337        }
+3338        // Before removing the path, we fetch the final path stats via `Self::path_stats`.
+3339        // This updates some values for the last time.
+3340        let path_stats = self.path_stats.discard(&path_id);
+3341        self.partial_stats += path_stats;
+3342        self.paths.remove(&path_id);
+3343        self.spaces[SpaceId::Data].number_spaces.remove(&path_id);
+3344
+3345        self.events.push_back(
+3346            PathEvent::Discarded {
+3347                id: path_id,
+3348                path_stats: Box::new(path_stats),
+3349            }
+3350            .into(),
+3351        );
+3352    }
+3353
+3354    fn handle_lost_packets(
+3355        &mut self,
+3356        pn_space: SpaceId,
+3357        path_id: PathId,
+3358        now: Instant,
+3359        lost_packets: Vec<u64>,
+3360        lost_mtu_probe: Option<u64>,
+3361        loss_delay: Duration,
+3362        in_persistent_congestion: bool,
+3363        size_of_lost_packets: u64,
+3364    ) {
+3365        debug_assert!(lost_packets.is_sorted(), "lost_packets must be sorted");
+3366
+3367        self.drain_lost_packets(now, pn_space, path_id);
+3368
+3369        // OnPacketsLost
+3370        if let Some(largest_lost) = lost_packets.last().cloned() {
+3371            let old_bytes_in_flight = self.path_data_mut(path_id).in_flight.bytes;
+3372            let largest_lost_sent = self.spaces[pn_space]
+3373                .for_path(path_id)
+3374                .sent_packets
+3375                .get(largest_lost)
+3376                .unwrap()
+3377                .time_sent;
+3378            let path_stats = self.path_stats.for_path(path_id);
+3379            path_stats.lost_packets += lost_packets.len() as u64;
+3380            path_stats.lost_bytes += size_of_lost_packets;
+3381            trace!(
+3382                %path_id,
+3383                count = lost_packets.len(),
+3384                lost_bytes = size_of_lost_packets,
+3385                "packets lost",
+3386            );
+3387
+3388            for &packet in &lost_packets {
+3389                let Some(info) = self.spaces[pn_space].for_path(path_id).take(packet) else {
+3390                    continue;
+3391                };
+3392                self.qlog
+3393                    .emit_packet_lost(packet, &info, loss_delay, pn_space.kind(), now);
+3394                self.paths
+3395                    .get_mut(&path_id)
+3396                    .unwrap()
+3397                    .remove_in_flight(&info);
+3398
+3399                for frame in info.stream_frames {
+3400                    self.streams.retransmit(frame);
+3401                }
+3402                self.spaces[pn_space].pending |= info.retransmits;
+3403                let path = self.path_data_mut(path_id);
+3404                path.mtud.on_non_probe_lost(packet, info.size);
+3405                path.congestion.on_packet_lost(info.size, packet, now);
+3406
+3407                self.spaces[pn_space].for_path(path_id).lost_packets.insert(
+3408                    packet,
+3409                    LostPacket {
+3410                        time_sent: info.time_sent,
+3411                    },
+3412                );
+3413            }
+3414
+3415            let path = self.path_data_mut(path_id);
+3416            if path.mtud.black_hole_detected(now) {
+3417                path.congestion.on_mtu_update(path.mtud.current_mtu());
+3418                if let Some(max_datagram_size) = self.datagrams().max_size()
+3419                    && self.datagrams.drop_oversized(max_datagram_size)
+3420                    && self.datagrams.send_blocked
+3421                {
+3422                    self.datagrams.send_blocked = false;
+3423                    self.events.push_back(Event::DatagramsUnblocked);
+3424                }
+3425                self.path_stats.for_path(path_id).black_holes_detected += 1;
+3426            }
+3427
+3428            // Don't apply congestion penalty for lost ack-only packets
+3429            let lost_ack_eliciting =
+3430                old_bytes_in_flight != self.path_data_mut(path_id).in_flight.bytes;
+3431
+3432            if lost_ack_eliciting {
+3433                self.path_stats.for_path(path_id).congestion_events += 1;
+3434                self.path_data_mut(path_id).congestion.on_congestion_event(
+3435                    now,
+3436                    largest_lost_sent,
+3437                    in_persistent_congestion,
+3438                    false,
+3439                    size_of_lost_packets,
+3440                    largest_lost,
+3441                );
+3442            }
+3443        }
+3444
+3445        // Handle a lost MTU probe
+3446        if let Some(packet) = lost_mtu_probe {
+3447            let info = self.spaces[SpaceId::Data]
+3448                .for_path(path_id)
+3449                .take(packet)
+3450                .unwrap(); // safe: lost_mtu_probe is omitted from lost_packets, and
+3451            // therefore must not have been removed yet
+3452            self.paths
+3453                .get_mut(&path_id)
+3454                .unwrap()
+3455                .remove_in_flight(&info);
+3456            self.path_data_mut(path_id).mtud.on_probe_lost();
+3457            self.path_stats.for_path(path_id).lost_plpmtud_probes += 1;
+3458        }
+3459    }
+3460
+3461    /// Returns the earliest time packets should be declared lost for all spaces on a path.
+3462    ///
+3463    /// If a path has an acknowledged packet with any prior un-acknowledged packets, the
+3464    /// earliest un-acknowledged packet can be declared lost after a timeout has elapsed.
+3465    /// The time returned is when this packet should be declared lost.
+3466    fn loss_time_and_space(&self, path_id: PathId) -> Option<(Instant, SpaceId)> {
+3467        SpaceId::iter()
+3468            .filter_map(|id| {
+3469                self.spaces[id]
+3470                    .number_spaces
+3471                    .get(&path_id)
+3472                    .and_then(|pns| pns.loss_time)
+3473                    .map(|time| (time, id))
+3474            })
+3475            .min_by_key(|&(time, _)| time)
+3476    }
+3477
+3478    /// Returns the earliest next PTO should fire for all spaces on a path.
+3479    ///
+3480    /// This needs to be fully deterministic because it is also used to determine the PTO
+3481    /// that fired, not just to set the next timer. So if it fired in the past it needs to
+3482    /// return the time from the past at which it fired.
+3483    ///
+3484    /// This is the next time a tail-loss probe should be sent.
+3485    fn pto_time_and_space(&mut self, now: Instant, path_id: PathId) -> Option<(Instant, SpaceId)> {
+3486        let path = self.path(path_id)?;
+3487        let pto_count = path.pto_count;
+3488
+3489        // Cap the maximum interval between two tail-loss probes.
+3490        let max_interval = if path.rtt.get() > SLOW_RTT_THRESHOLD {
+3491            // For slow links we want to increase the interval beyond 2s.
+3492            (path.rtt.get() * 3) / 2
+3493        } else if let Some(idle) = path.idle_timeout.or(self.idle_timeout)
+3494            && idle <= MIN_IDLE_FOR_FAST_PTO
+3495        {
+3496            // If the idle timeout is relatively low, cap at 1s so we get plenty of retries
+3497            // before the idle timeout fires.
+3498            MAX_PTO_FAST_INTERVAL
+3499        } else {
+3500            // Otherwise cap to 2s.
+3501            MAX_PTO_INTERVAL
+3502        };
+3503
+3504        if path_id == PathId::ZERO
+3505            && path.in_flight.ack_eliciting == 0
+3506            && !self.peer_completed_handshake_address_validation()
+3507        {
+3508            // Address Validation during Connection Establishment:
+3509            // https://www.rfc-editor.org/rfc/rfc9000.html#section-8.1. To prevent a
+3510            // deadlock if an Initial or Handshake packet from the server is lost and the
+3511            // server can not send more due to its anti-amplification limit the client must
+3512            // send another packet on PTO.
+3513            let space = match self.highest_space {
+3514                SpaceKind::Handshake => SpaceId::Handshake,
+3515                _ => SpaceId::Initial,
+3516            };
+3517
+3518            let backoff = 2u32.pow(path.pto_count.min(MAX_BACKOFF_EXPONENT));
+3519            let duration = path.rtt.pto_base() * backoff;
+3520            let duration = duration.min(max_interval);
+3521            return Some((now + duration, space));
+3522        }
+3523
+3524        let mut result = None;
+3525        for space in SpaceId::iter() {
+3526            let Some(pns) = self.spaces[space].number_spaces.get(&path_id) else {
+3527                continue;
+3528            };
 3529
-3530            if !pns.has_in_flight() {
-3531                continue;
-3532            }
-3533
-3534            // Compute the PTO duration for this space, we want to cap the maximum interval
-3535            // between two tail-loss probes so to not do a simple exponential backoff but
-3536            // rather iterate through the probes to compute the capped increment for an
-3537            // exponential backoff at each step.
-3538            let duration = {
-3539                let max_ack_delay = if space == SpaceId::Data {
-3540                    self.ack_frequency.max_ack_delay_for_pto()
-3541                } else {
-3542                    Duration::ZERO
-3543                };
-3544                let pto_base = path.rtt.pto_base() + max_ack_delay;
-3545                let mut duration = pto_base;
-3546                for i in 1..=pto_count {
-3547                    let exponential_duration = pto_base * 2u32.pow(i.min(MAX_BACKOFF_EXPONENT));
-3548                    let max_duration = duration + max_interval;
-3549                    duration = exponential_duration.min(max_duration);
-3550                }
-3551                duration
-3552            };
-3553
-3554            let Some(last_ack_eliciting) = pns.time_of_last_ack_eliciting_packet else {
-3555                continue;
-3556            };
-3557            // Base the deadline on when the last probe was sent, so the PTO
-3558            // doesn't fire before the response has had time to arrive.
-3559            let pto = last_ack_eliciting + duration;
-3560            if result.is_none_or(|(earliest_pto, _)| pto < earliest_pto) {
-3561                if path.anti_amplification_blocked(1) {
-3562                    // Nothing would be able to be sent.
-3563                    continue;
-3564                }
-3565                if path.in_flight.ack_eliciting == 0 {
-3566                    // Nothing ack-eliciting, no PTO to arm/fire.
-3567                    continue;
-3568                }
-3569                result = Some((pto, space));
-3570            }
-3571        }
-3572        result
-3573    }
-3574
-3575    /// Whether the peer validated our address in the connection handshake.
-3576    fn peer_completed_handshake_address_validation(&self) -> bool {
-3577        if self.side.is_server() || self.state.is_closed() {
-3578            return true;
-3579        }
-3580        // The server is guaranteed to have validated our address if any of our handshake or
-3581        // 1-RTT packets are acknowledged or we've seen HANDSHAKE_DONE and discarded
-3582        // handshake keys.
-3583        self.spaces[SpaceId::Handshake]
-3584            .path_space(PathId::ZERO)
-3585            .and_then(|pns| pns.largest_acked_packet_pn)
-3586            .is_some()
-3587            || self.spaces[SpaceId::Data]
-3588                .path_space(PathId::ZERO)
-3589                .and_then(|pns| pns.largest_acked_packet_pn)
-3590                .is_some()
-3591            || (self.crypto_state.has_keys(EncryptionLevel::OneRtt)
-3592                && !self.crypto_state.has_keys(EncryptionLevel::Handshake))
-3593    }
-3594
-3595    /// Resets the the [`PathTimer::LossDetection`] timer to the next instant it may be needed
-3596    ///
-3597    /// The timer must fire if either:
-3598    /// - An ack-eliciting packet we sent needs to be declared lost.
-3599    /// - A tail-loss probe needs to be sent.
-3600    ///
-3601    /// See [`Connection::on_loss_detection_timeout`] for details.
-3602    fn set_loss_detection_timer(&mut self, now: Instant, path_id: PathId) {
-3603        if self.state.is_closed() {
-3604            // No loss detection takes place on closed connections, and `close_common` already
-3605            // stopped time timer. Ensure we don't restart it inadvertently, e.g. in response to a
-3606            // reordered packet being handled by state-insensitive code.
-3607            return;
-3608        }
-3609
-3610        if let Some((loss_time, _)) = self.loss_time_and_space(path_id) {
-3611            // Time threshold loss detection.
-3612            self.timers.set(
-3613                Timer::PerPath(path_id, PathTimer::LossDetection),
-3614                loss_time,
-3615                self.qlog.with_time(now),
-3616            );
-3617            return;
-3618        }
-3619
-3620        // Determine which PN space to arm PTO for.
-3621        // We can only send tail-loss probes on paths that aren't abandoned yet.
-3622        if !self.abandoned_paths.contains(&path_id)
-3623            && let Some((timeout, _)) = self.pto_time_and_space(now, path_id)
-3624        {
-3625            self.timers.set(
-3626                Timer::PerPath(path_id, PathTimer::LossDetection),
-3627                timeout,
-3628                self.qlog.with_time(now),
-3629            );
-3630        } else {
-3631            self.timers.stop(
-3632                Timer::PerPath(path_id, PathTimer::LossDetection),
-3633                self.qlog.with_time(now),
-3634            );
-3635        }
-3636    }
-3637
-3638    /// The maximum probe timeout across all paths
-3639    ///
-3640    /// See [`Connection::pto`]
-3641    fn max_pto_for_space(&self, space: SpaceKind) -> Duration {
-3642        self.paths
-3643            .keys()
-3644            .map(|path_id| self.pto(space, *path_id))
-3645            .max()
-3646            .unwrap_or_else(|| {
-3647                // No paths remain (e.g. last path was abandoned and the NoAvailablePath grace timer
-3648                // fired before any new path was opened). Fall back to a PTO derived from the
-3649                // configured initial RTT, matching RFC 9002 §6.2.2 initial values.
-3650                let rtt = self.config.initial_rtt;
-3651                let max_ack_delay = match space {
-3652                    SpaceKind::Initial | SpaceKind::Handshake => Duration::ZERO,
-3653                    SpaceKind::Data => self.ack_frequency.max_ack_delay_for_pto(),
-3654                };
-3655                rtt + cmp::max(4 * (rtt / 2), TIMER_GRANULARITY) + max_ack_delay
-3656            })
-3657    }
-3658
-3659    /// Probe Timeout
-3660    ///
-3661    /// The PTO is logically the time in which you'd expect to receive an acknowledgement
-3662    /// for a packet. So approximately RTT + max_ack_delay.
-3663    fn pto(&self, space: SpaceKind, path_id: PathId) -> Duration {
-3664        let max_ack_delay = match space {
-3665            SpaceKind::Initial | SpaceKind::Handshake => Duration::ZERO,
-3666            SpaceKind::Data => self.ack_frequency.max_ack_delay_for_pto(),
-3667        };
-3668        self.path_data(path_id).rtt.pto_base() + max_ack_delay
-3669    }
-3670
-3671    fn on_packet_authenticated(
-3672        &mut self,
-3673        now: Instant,
-3674        space_id: SpaceKind,
-3675        path_id: PathId,
-3676        ecn: Option<EcnCodepoint>,
-3677        packet_number: Option<u64>,
-3678        spin: bool,
-3679        is_1rtt: bool,
-3680        remote: &FourTuple,
-3681    ) {
-3682        // During the handshake we already have discarded packets that do not match the path
-3683        // remote. So any off-path packet here is either a probing packet or a
-3684        // migration. Handling probing packets here means that the path's idle timeout will
-3685        // be reset and will delay detecting the path as idle. However tail-loss probes
-3686        // would still not get acknowledged if the path was broken so eventually the path
-3687        // would still become idle.
-3688        let is_on_path = *remote == self.path_data(path_id).network_path;
-3689
-3690        self.total_authed_packets += 1;
-3691        self.reset_keep_alive(path_id, now);
-3692        self.reset_idle_timeout(now, space_id, path_id);
-3693        self.path_data_mut(path_id).permit_idle_reset = true;
-3694
-3695        // Do not process ECN for off-path packets. If this is a migration we'll get ECN
-3696        // back once we've migrated.
-3697        if is_on_path {
-3698            self.receiving_ecn |= ecn.is_some();
-3699            if let Some(x) = ecn {
-3700                let space = &mut self.spaces[space_id];
-3701                space.for_path(path_id).ecn_counters += x;
-3702
-3703                if x.is_ce() {
-3704                    space
-3705                        .for_path(path_id)
-3706                        .pending_acks
-3707                        .set_immediate_ack_required();
-3708                }
-3709            }
-3710        }
-3711
-3712        let Some(packet_number) = packet_number else {
-3713            return;
-3714        };
-3715        match &self.side {
-3716            ConnectionSide::Client { .. } => {
-3717                // If we received a handshake packet that authenticated, then we're talking to
-3718                // the real server.  From now on we should no longer allow the server to migrate
-3719                // its address.
-3720                if space_id == SpaceKind::Handshake
-3721                    && let Some(hs) = self.state.as_handshake_mut()
-3722                {
-3723                    hs.allow_server_migration = false;
-3724                }
-3725            }
-3726            ConnectionSide::Server { .. } => {
-3727                if self.crypto_state.has_keys(EncryptionLevel::Initial)
-3728                    && space_id == SpaceKind::Handshake
+3530            if space == SpaceId::Data && !self.is_handshake_confirmed() {
+3531                // https://www.rfc-editor.org/rfc/rfc9002.html#section-6.2.1-7:
+3532                // An endpoint MUST NOT set its PTO timer for the Application Data packet
+3533                // number space until the handshake is confirmed.
+3534                continue;
+3535            }
+3536
+3537            if !pns.has_in_flight() {
+3538                continue;
+3539            }
+3540
+3541            // Compute the PTO duration for this space, we want to cap the maximum interval
+3542            // between two tail-loss probes so to not do a simple exponential backoff but
+3543            // rather iterate through the probes to compute the capped increment for an
+3544            // exponential backoff at each step.
+3545            let duration = {
+3546                let max_ack_delay = if space == SpaceId::Data {
+3547                    self.ack_frequency.max_ack_delay_for_pto()
+3548                } else {
+3549                    Duration::ZERO
+3550                };
+3551                let pto_base = path.rtt.pto_base() + max_ack_delay;
+3552                let mut duration = pto_base;
+3553                for i in 1..=pto_count {
+3554                    let exponential_duration = pto_base * 2u32.pow(i.min(MAX_BACKOFF_EXPONENT));
+3555                    let max_duration = duration + max_interval;
+3556                    duration = exponential_duration.min(max_duration);
+3557                }
+3558                duration
+3559            };
+3560
+3561            let Some(last_ack_eliciting) = pns.time_of_last_ack_eliciting_packet else {
+3562                continue;
+3563            };
+3564            // Base the deadline on when the last probe was sent, so the PTO
+3565            // doesn't fire before the response has had time to arrive.
+3566            let pto = last_ack_eliciting + duration;
+3567            if result.is_none_or(|(earliest_pto, _)| pto < earliest_pto) {
+3568                if path.anti_amplification_blocked(1) {
+3569                    // Nothing would be able to be sent.
+3570                    continue;
+3571                }
+3572                if path.in_flight.ack_eliciting == 0 {
+3573                    // Nothing ack-eliciting, no PTO to arm/fire.
+3574                    continue;
+3575                }
+3576                result = Some((pto, space));
+3577            }
+3578        }
+3579        result
+3580    }
+3581
+3582    /// Whether the peer validated our address in the connection handshake.
+3583    fn peer_completed_handshake_address_validation(&self) -> bool {
+3584        if self.side.is_server() || self.state.is_closed() {
+3585            return true;
+3586        }
+3587        // The server is guaranteed to have validated our address if any of our handshake or
+3588        // 1-RTT packets are acknowledged or we've seen HANDSHAKE_DONE and discarded
+3589        // handshake keys.
+3590        self.spaces[SpaceId::Handshake]
+3591            .path_space(PathId::ZERO)
+3592            .and_then(|pns| pns.largest_acked_packet_pn)
+3593            .is_some()
+3594            || self.spaces[SpaceId::Data]
+3595                .path_space(PathId::ZERO)
+3596                .and_then(|pns| pns.largest_acked_packet_pn)
+3597                .is_some()
+3598            || (self.crypto_state.has_keys(EncryptionLevel::OneRtt)
+3599                && !self.crypto_state.has_keys(EncryptionLevel::Handshake))
+3600    }
+3601
+3602    /// Resets the the [`PathTimer::LossDetection`] timer to the next instant it may be needed
+3603    ///
+3604    /// The timer must fire if either:
+3605    /// - An ack-eliciting packet we sent needs to be declared lost.
+3606    /// - A tail-loss probe needs to be sent.
+3607    ///
+3608    /// See [`Connection::on_loss_detection_timeout`] for details.
+3609    fn set_loss_detection_timer(&mut self, now: Instant, path_id: PathId) {
+3610        if self.state.is_closed() {
+3611            // No loss detection takes place on closed connections, and `close_common` already
+3612            // stopped time timer. Ensure we don't restart it inadvertently, e.g. in response to a
+3613            // reordered packet being handled by state-insensitive code.
+3614            return;
+3615        }
+3616
+3617        if let Some((loss_time, _)) = self.loss_time_and_space(path_id) {
+3618            // Time threshold loss detection.
+3619            self.timers.set(
+3620                Timer::PerPath(path_id, PathTimer::LossDetection),
+3621                loss_time,
+3622                self.qlog.with_time(now),
+3623            );
+3624            return;
+3625        }
+3626
+3627        // Determine which PN space to arm PTO for.
+3628        // We can only send tail-loss probes on paths that aren't abandoned yet.
+3629        if !self.abandoned_paths.contains(&path_id)
+3630            && let Some((timeout, _)) = self.pto_time_and_space(now, path_id)
+3631        {
+3632            self.timers.set(
+3633                Timer::PerPath(path_id, PathTimer::LossDetection),
+3634                timeout,
+3635                self.qlog.with_time(now),
+3636            );
+3637        } else {
+3638            self.timers.stop(
+3639                Timer::PerPath(path_id, PathTimer::LossDetection),
+3640                self.qlog.with_time(now),
+3641            );
+3642        }
+3643    }
+3644
+3645    /// The maximum probe timeout across all paths
+3646    ///
+3647    /// See [`Connection::pto`]
+3648    fn max_pto_for_space(&self, space: SpaceKind) -> Duration {
+3649        self.paths
+3650            .keys()
+3651            .map(|path_id| self.pto(space, *path_id))
+3652            .max()
+3653            .unwrap_or_else(|| {
+3654                // No paths remain (e.g. last path was abandoned and the NoAvailablePath grace timer
+3655                // fired before any new path was opened). Fall back to a PTO derived from the
+3656                // configured initial RTT, matching RFC 9002 §6.2.2 initial values.
+3657                let rtt = self.config.initial_rtt;
+3658                let max_ack_delay = match space {
+3659                    SpaceKind::Initial | SpaceKind::Handshake => Duration::ZERO,
+3660                    SpaceKind::Data => self.ack_frequency.max_ack_delay_for_pto(),
+3661                };
+3662                rtt + cmp::max(4 * (rtt / 2), TIMER_GRANULARITY) + max_ack_delay
+3663            })
+3664    }
+3665
+3666    /// Probe Timeout
+3667    ///
+3668    /// The PTO is logically the time in which you'd expect to receive an acknowledgement
+3669    /// for a packet. So approximately RTT + max_ack_delay.
+3670    fn pto(&self, space: SpaceKind, path_id: PathId) -> Duration {
+3671        let max_ack_delay = match space {
+3672            SpaceKind::Initial | SpaceKind::Handshake => Duration::ZERO,
+3673            SpaceKind::Data => self.ack_frequency.max_ack_delay_for_pto(),
+3674        };
+3675        self.path_data(path_id).rtt.pto_base() + max_ack_delay
+3676    }
+3677
+3678    fn on_packet_authenticated(
+3679        &mut self,
+3680        now: Instant,
+3681        space_id: SpaceKind,
+3682        path_id: PathId,
+3683        ecn: Option<EcnCodepoint>,
+3684        packet_number: Option<u64>,
+3685        spin: bool,
+3686        is_1rtt: bool,
+3687        remote: &FourTuple,
+3688    ) {
+3689        // During the handshake we already have discarded packets that do not match the path
+3690        // remote. So any off-path packet here is either a probing packet or a
+3691        // migration. Handling probing packets here means that the path's idle timeout will
+3692        // be reset and will delay detecting the path as idle. However tail-loss probes
+3693        // would still not get acknowledged if the path was broken so eventually the path
+3694        // would still become idle.
+3695        let is_on_path = *remote == self.path_data(path_id).network_path;
+3696
+3697        self.total_authed_packets += 1;
+3698        self.reset_keep_alive(path_id, now);
+3699        self.reset_idle_timeout(now, space_id, path_id);
+3700        self.path_data_mut(path_id).permit_idle_reset = true;
+3701
+3702        // Do not process ECN for off-path packets. If this is a migration we'll get ECN
+3703        // back once we've migrated.
+3704        if is_on_path {
+3705            self.receiving_ecn |= ecn.is_some();
+3706            if let Some(x) = ecn {
+3707                let space = &mut self.spaces[space_id];
+3708                space.for_path(path_id).ecn_counters += x;
+3709
+3710                if x.is_ce() {
+3711                    space
+3712                        .for_path(path_id)
+3713                        .pending_acks
+3714                        .set_immediate_ack_required();
+3715                }
+3716            }
+3717        }
+3718
+3719        let Some(packet_number) = packet_number else {
+3720            return;
+3721        };
+3722        match &self.side {
+3723            ConnectionSide::Client { .. } => {
+3724                // If we received a handshake packet that authenticated, then we're talking to
+3725                // the real server.  From now on we should no longer allow the server to migrate
+3726                // its address.
+3727                if space_id == SpaceKind::Handshake
+3728                    && let Some(hs) = self.state.as_handshake_mut()
 3729                {
-3730                    // A server stops sending and processing Initial packets when it receives its first Handshake packet.
-3731                    self.discard_space(now, SpaceKind::Initial);
-3732                }
-3733                if self.crypto_state.has_keys(EncryptionLevel::ZeroRtt) && is_1rtt {
-3734                    // Discard 0-RTT keys soon after receiving a 1-RTT packet
-3735                    self.set_key_discard_timer(now, space_id)
-3736                }
-3737            }
-3738        }
-3739        let space = self.spaces[space_id].for_path(path_id);
-3740
-3741        space.pending_acks.insert_one(packet_number, now);
-3742        if packet_number >= space.largest_received_packet_number.unwrap_or_default() {
-3743            space.largest_received_packet_number = Some(packet_number);
-3744
-3745            // Update outgoing spin bit for on-path packets, inverting iff we're the client
-3746            if is_on_path {
-3747                self.spin = self.side.is_client() ^ spin;
-3748            }
-3749        }
-3750    }
+3730                    hs.allow_server_migration = false;
+3731                }
+3732            }
+3733            ConnectionSide::Server { .. } => {
+3734                if self.crypto_state.has_keys(EncryptionLevel::Initial)
+3735                    && space_id == SpaceKind::Handshake
+3736                {
+3737                    // A server stops sending and processing Initial packets when it receives its first Handshake packet.
+3738                    self.discard_space(now, SpaceKind::Initial);
+3739                }
+3740                if self.crypto_state.has_keys(EncryptionLevel::ZeroRtt) && is_1rtt {
+3741                    // Discard 0-RTT keys soon after receiving a 1-RTT packet
+3742                    self.set_key_discard_timer(now, space_id)
+3743                }
+3744            }
+3745        }
+3746        let space = self.spaces[space_id].for_path(path_id);
+3747
+3748        space.pending_acks.insert_one(packet_number, now);
+3749        if packet_number >= space.largest_received_packet_number.unwrap_or_default() {
+3750            space.largest_received_packet_number = Some(packet_number);
 3751
-3752    /// Resets the idle timeout timers
-3753    ///
-3754    /// Without multipath there is only the connection-wide idle timeout. When multipath is
-3755    /// enabled there is an additional per-path idle timeout.
-3756    fn reset_idle_timeout(&mut self, now: Instant, space: SpaceKind, path_id: PathId) {
-3757        // First reset the global idle timeout.
-3758        if let Some(timeout) = self.idle_timeout {
-3759            if self.state.is_closed() {
-3760                self.timers
-3761                    .stop(Timer::Conn(ConnTimer::Idle), self.qlog.with_time(now));
-3762            } else {
-3763                let dt = cmp::max(timeout, 3 * self.max_pto_for_space(space));
-3764                self.timers.set(
-3765                    Timer::Conn(ConnTimer::Idle),
-3766                    now + dt,
-3767                    self.qlog.with_time(now),
-3768                );
-3769            }
-3770        }
-3771
-3772        // Now handle the per-path state
-3773        if let Some(timeout) = self.path_data(path_id).idle_timeout {
-3774            if self.state.is_closed() {
-3775                self.timers.stop(
-3776                    Timer::PerPath(path_id, PathTimer::PathIdle),
-3777                    self.qlog.with_time(now),
-3778                );
-3779            } else {
-3780                let dt = cmp::max(timeout, 3 * self.pto(space, path_id));
-3781                self.timers.set(
-3782                    Timer::PerPath(path_id, PathTimer::PathIdle),
-3783                    now + dt,
+3752            // Update outgoing spin bit for on-path packets, inverting iff we're the client
+3753            if is_on_path {
+3754                self.spin = self.side.is_client() ^ spin;
+3755            }
+3756        }
+3757    }
+3758
+3759    /// Resets the idle timeout timers
+3760    ///
+3761    /// Without multipath there is only the connection-wide idle timeout. When multipath is
+3762    /// enabled there is an additional per-path idle timeout.
+3763    fn reset_idle_timeout(&mut self, now: Instant, space: SpaceKind, path_id: PathId) {
+3764        // First reset the global idle timeout.
+3765        if let Some(timeout) = self.idle_timeout {
+3766            if self.state.is_closed() {
+3767                self.timers
+3768                    .stop(Timer::Conn(ConnTimer::Idle), self.qlog.with_time(now));
+3769            } else {
+3770                let dt = cmp::max(timeout, 3 * self.max_pto_for_space(space));
+3771                self.timers.set(
+3772                    Timer::Conn(ConnTimer::Idle),
+3773                    now + dt,
+3774                    self.qlog.with_time(now),
+3775                );
+3776            }
+3777        }
+3778
+3779        // Now handle the per-path state
+3780        if let Some(timeout) = self.path_data(path_id).idle_timeout {
+3781            if self.state.is_closed() {
+3782                self.timers.stop(
+3783                    Timer::PerPath(path_id, PathTimer::PathIdle),
 3784                    self.qlog.with_time(now),
 3785                );
-3786            }
-3787        }
-3788    }
-3789
-3790    /// Resets both the [`ConnTimer::KeepAlive`] and [`PathTimer::PathKeepAlive`] timers
-3791    fn reset_keep_alive(&mut self, path_id: PathId, now: Instant) {
-3792        if !self.state.is_established() {
-3793            return;
+3786            } else {
+3787                let dt = cmp::max(timeout, 3 * self.pto(space, path_id));
+3788                self.timers.set(
+3789                    Timer::PerPath(path_id, PathTimer::PathIdle),
+3790                    now + dt,
+3791                    self.qlog.with_time(now),
+3792                );
+3793            }
 3794        }
-3795
-3796        if let Some(interval) = self.config.keep_alive_interval {
-3797            self.timers.set(
-3798                Timer::Conn(ConnTimer::KeepAlive),
-3799                now + interval,
-3800                self.qlog.with_time(now),
-3801            );
-3802        }
-3803
-3804        if let Some(interval) = self.path_data(path_id).keep_alive {
-3805            self.timers.set(
-3806                Timer::PerPath(path_id, PathTimer::PathKeepAlive),
-3807                now + interval,
-3808                self.qlog.with_time(now),
-3809            );
-3810        }
-3811    }
-3812
-3813    /// Sets the timer for when a previously issued CID should be retired next
-3814    fn reset_cid_retirement(&mut self, now: Instant) {
-3815        if let Some((_path, t)) = self.next_cid_retirement() {
-3816            self.timers.set(
-3817                Timer::Conn(ConnTimer::PushNewCid),
-3818                t,
-3819                self.qlog.with_time(now),
-3820            );
-3821        }
-3822    }
-3823
-3824    /// The next time when a previously issued CID should be retired
-3825    fn next_cid_retirement(&self) -> Option<(PathId, Instant)> {
-3826        self.local_cid_state
-3827            .iter()
-3828            .filter_map(|(path_id, cid_state)| cid_state.next_timeout().map(|t| (*path_id, t)))
-3829            .min_by_key(|(_path_id, timeout)| *timeout)
-3830    }
-3831
-3832    /// Handle the already-decrypted first packet from the client
-3833    ///
-3834    /// Decrypting the first packet in the `Endpoint` allows stateless packet handling to be more
-3835    /// efficient.
-3836    pub(crate) fn handle_first_packet(
-3837        &mut self,
-3838        now: Instant,
-3839        network_path: FourTuple,
-3840        ecn: Option<EcnCodepoint>,
-3841        packet_number: u64,
-3842        packet: InitialPacket,
-3843        remaining: Option<BytesMut>,
-3844    ) -> Result<(), ConnectionError> {
-3845        let span = trace_span!("first recv");
-3846        let _guard = span.enter();
-3847        debug_assert!(self.side.is_server());
-3848        let len = packet.header_data.len() + packet.payload.len();
-3849        let path_id = PathId::ZERO;
-3850        self.path_data_mut(path_id).total_recvd = len as u64;
-3851
-3852        if let Some(hs) = self.state.as_handshake_mut() {
-3853            hs.expected_token = packet.header.token.clone();
-3854        } else {
-3855            unreachable!("first packet must be delivered in Handshake state");
-3856        }
-3857
-3858        // The first packet is always on PathId::ZERO
-3859        self.on_packet_authenticated(
-3860            now,
-3861            SpaceKind::Initial,
-3862            path_id,
-3863            ecn,
-3864            Some(packet_number),
-3865            false,
-3866            false,
-3867            &network_path,
-3868        );
-3869
-3870        let packet: Packet = packet.into();
-3871
-3872        let mut qlog = QlogRecvPacket::new(len);
-3873        qlog.header(&packet.header, Some(packet_number), path_id);
-3874
-3875        self.process_decrypted_packet(
-3876            now,
-3877            network_path,
-3878            path_id,
-3879            Some(packet_number),
-3880            packet,
-3881            &mut qlog,
-3882        )?;
-3883        self.qlog.emit_packet_received(qlog, now);
-3884        if let Some(data) = remaining {
-3885            self.handle_coalesced(now, network_path, path_id, ecn, data);
-3886        }
-3887
-3888        self.qlog.emit_recovery_metrics(
-3889            path_id,
-3890            &mut self
-3891                .paths
-3892                .get_mut(&path_id)
-3893                .expect("path_id was supplied by the caller for an active path")
-3894                .data,
-3895            now,
-3896        );
-3897
-3898        Ok(())
-3899    }
-3900
-3901    fn init_0rtt(&mut self, now: Instant) {
-3902        let Some((header, packet)) = self.crypto_state.session.early_crypto() else {
-3903            return;
-3904        };
-3905        if self.side.is_client() {
-3906            match self.crypto_state.session.transport_parameters() {
-3907                Ok(params) => {
-3908                    let params = params
-3909                        .expect("crypto layer didn't supply transport parameters with ticket");
-3910                    // Certain values must not be cached
-3911                    let params = TransportParameters {
-3912                        initial_src_cid: None,
-3913                        original_dst_cid: None,
-3914                        preferred_address: None,
-3915                        retry_src_cid: None,
-3916                        stateless_reset_token: None,
-3917                        min_ack_delay: None,
-3918                        ack_delay_exponent: TransportParameters::default().ack_delay_exponent,
-3919                        max_ack_delay: TransportParameters::default().max_ack_delay,
-3920                        initial_max_path_id: None,
-3921                        ..params
-3922                    };
-3923                    self.set_peer_params(params);
-3924                    self.qlog.emit_peer_transport_params_restored(self, now);
-3925                }
-3926                Err(e) => {
-3927                    error!("session ticket has malformed transport parameters: {}", e);
-3928                    return;
-3929                }
-3930            }
-3931        }
-3932        trace!("0-RTT enabled");
-3933        self.crypto_state.enable_zero_rtt(header, packet);
-3934    }
-3935
-3936    fn read_crypto(
-3937        &mut self,
-3938        space: SpaceId,
-3939        crypto: &frame::Crypto,
-3940        payload_len: usize,
-3941    ) -> Result<(), TransportError> {
-3942        let expected = if !self.state.is_handshake() {
-3943            SpaceId::Data
-3944        } else if self.highest_space == SpaceKind::Initial {
-3945            SpaceId::Initial
-3946        } else {
-3947            // On the server, self.highest_space can be Data after receiving the client's first
-3948            // flight, but we expect Handshake CRYPTO until the handshake is complete.
-3949            SpaceId::Handshake
-3950        };
-3951        // We can't decrypt Handshake packets when highest_space is Initial, CRYPTO frames in 0-RTT
-3952        // packets are illegal, and we don't process 1-RTT packets until the handshake is
-3953        // complete. Therefore, we will never see CRYPTO data from a later-than-expected space.
-3954        debug_assert!(space <= expected, "received out-of-order CRYPTO data");
-3955
-3956        let end = crypto.offset + crypto.data.len() as u64;
-3957        if space < expected
-3958            && end
-3959                > self.crypto_state.spaces[space.kind()]
-3960                    .crypto_stream
-3961                    .bytes_read()
-3962        {
-3963            warn!(
-3964                "received new {:?} CRYPTO data when expecting {:?}",
-3965                space, expected
-3966            );
-3967            return Err(TransportError::PROTOCOL_VIOLATION(
-3968                "new data at unexpected encryption level",
-3969            ));
-3970        }
-3971
-3972        let crypto_space = &mut self.crypto_state.spaces[space.kind()];
-3973        let max = end.saturating_sub(crypto_space.crypto_stream.bytes_read());
-3974        if max > self.config.crypto_buffer_size as u64 {
-3975            return Err(TransportError::CRYPTO_BUFFER_EXCEEDED(""));
-3976        }
-3977
-3978        crypto_space
-3979            .crypto_stream
-3980            .insert(crypto.offset, crypto.data.clone(), payload_len);
-3981        while let Some(chunk) = crypto_space.crypto_stream.read(usize::MAX, true) {
-3982            trace!("consumed {} CRYPTO bytes", chunk.bytes.len());
-3983            if self.crypto_state.session.read_handshake(&chunk.bytes)? {
-3984                self.events.push_back(Event::HandshakeDataReady);
-3985            }
-3986        }
-3987
-3988        Ok(())
-3989    }
-3990
-3991    fn write_crypto(&mut self) {
-3992        loop {
-3993            let space = self.highest_space;
-3994            let mut outgoing = Vec::new();
-3995            if let Some(crypto) = self.crypto_state.session.write_handshake(&mut outgoing) {
-3996                match space {
-3997                    SpaceKind::Initial => {
-3998                        self.upgrade_crypto(SpaceKind::Handshake, crypto);
-3999                    }
-4000                    SpaceKind::Handshake => {
-4001                        self.upgrade_crypto(SpaceKind::Data, crypto);
-4002                    }
-4003                    SpaceKind::Data => unreachable!("got updated secrets during 1-RTT"),
-4004                }
-4005            }
-4006            if outgoing.is_empty() {
-4007                if space == self.highest_space {
-4008                    break;
-4009                } else {
-4010                    // Keys updated, check for more data to send
-4011                    continue;
-4012                }
-4013            }
-4014            let offset = self.crypto_state.spaces[space].crypto_offset;
-4015            let outgoing = Bytes::from(outgoing);
-4016            if let Some(hs) = self.state.as_handshake_mut()
-4017                && space == SpaceKind::Initial
-4018                && offset == 0
-4019                && self.side.is_client()
-4020            {
-4021                hs.client_hello = Some(outgoing.clone());
-4022            }
-4023            self.crypto_state.spaces[space].crypto_offset += outgoing.len() as u64;
-4024            trace!("wrote {} {:?} CRYPTO bytes", outgoing.len(), space);
-4025            self.spaces[space].pending.crypto.push_back(frame::Crypto {
-4026                offset,
-4027                data: outgoing,
-4028            });
-4029        }
-4030    }
-4031
-4032    /// Switch to stronger cryptography during handshake
-4033    fn upgrade_crypto(&mut self, space: SpaceKind, crypto: Keys) {
-4034        debug_assert!(
-4035            !self.crypto_state.has_keys(space.encryption_level()),
-4036            "already reached packet space {space:?}"
-4037        );
-4038        trace!("{:?} keys ready", space);
-4039        if space == SpaceKind::Data {
-4040            // Precompute the first key update
-4041            self.crypto_state.next_crypto = Some(
-4042                self.crypto_state
-4043                    .session
-4044                    .next_1rtt_keys()
-4045                    .expect("handshake should be complete"),
-4046            );
-4047        }
-4048
-4049        self.crypto_state.spaces[space].keys = Some(crypto);
-4050        debug_assert!(space > self.highest_space);
-4051        self.highest_space = space;
-4052        if space == SpaceKind::Data && self.side.is_client() {
-4053            // Discard 0-RTT keys because 1-RTT keys are available.
-4054            self.crypto_state.discard_zero_rtt();
-4055        }
-4056    }
-4057
-4058    fn discard_space(&mut self, now: Instant, space: SpaceKind) {
-4059        debug_assert!(space != SpaceKind::Data);
-4060        trace!("discarding {:?} keys", space);
-4061        if space == SpaceKind::Initial {
-4062            // No longer needed
-4063            if let ConnectionSide::Client { token, .. } = &mut self.side {
-4064                *token = Bytes::new();
-4065            }
-4066        }
-4067        self.crypto_state.spaces[space].keys = None;
-4068        let space = &mut self.spaces[space];
-4069        let pns = space.for_path(PathId::ZERO);
-4070        pns.time_of_last_ack_eliciting_packet = None;
-4071        pns.loss_time = None;
-4072        pns.loss_probes = 0;
-4073        let sent_packets = mem::take(&mut pns.sent_packets);
-4074        let path = self
-4075            .paths
-4076            .get_mut(&PathId::ZERO)
-4077            .expect("PathId::ZERO is alive while Initial/Handshake spaces exist");
-4078        for (_, packet) in sent_packets.into_iter() {
-4079            path.data.remove_in_flight(&packet);
-4080        }
-4081
-4082        self.set_loss_detection_timer(now, PathId::ZERO)
-4083    }
-4084
-4085    fn handle_coalesced(
-4086        &mut self,
-4087        now: Instant,
-4088        network_path: FourTuple,
-4089        path_id: PathId,
-4090        ecn: Option<EcnCodepoint>,
-4091        data: BytesMut,
-4092    ) {
-4093        self.path_data_mut(path_id)
-4094            .inc_total_recvd(data.len() as u64);
-4095        let mut remaining = Some(data);
-4096        let cid_len = self
-4097            .local_cid_state
-4098            .values()
-4099            .map(|cid_state| cid_state.cid_len())
-4100            .next()
-4101            .expect("one cid_state must exist");
-4102        while let Some(data) = remaining {
-4103            match PartialDecode::new(
-4104                data,
-4105                &FixedLengthConnectionIdParser::new(cid_len),
-4106                &[self.version],
-4107                self.endpoint_config.grease_quic_bit,
-4108            ) {
-4109                Ok((partial_decode, rest)) => {
-4110                    remaining = rest;
-4111                    self.handle_decode(now, network_path, path_id, ecn, partial_decode);
-4112                }
-4113                Err(e) => {
-4114                    trace!("malformed header: {}", e);
-4115                    return;
-4116                }
-4117            }
-4118        }
-4119    }
-4120
-4121    /// Decrypts the packet and processes the payload.
-4122    ///
-4123    /// Processes the entire packet, starting with removing header protection, then handling
-4124    /// a stateless reset if needed, and decrypting and processing the frames in the payload
-4125    /// if not a stateless reset.
-4126    fn handle_decode(
-4127        &mut self,
-4128        now: Instant,
-4129        network_path: FourTuple,
-4130        path_id: PathId,
-4131        ecn: Option<EcnCodepoint>,
-4132        partial_decode: PartialDecode,
-4133    ) {
-4134        let qlog = QlogRecvPacket::new(partial_decode.len());
-4135        if let Some(decoded) = self
-4136            .crypto_state
-4137            .unprotect_header(partial_decode, self.peer_params.stateless_reset_token)
-4138        {
-4139            self.handle_packet(
-4140                now,
-4141                network_path,
-4142                path_id,
-4143                ecn,
-4144                decoded.packet,
-4145                decoded.stateless_reset,
-4146                qlog,
-4147            );
-4148        }
-4149    }
-4150
-4151    /// Handles a packet with header protection removed.
-4152    ///
-4153    /// The packet body is still encrypted at this point.
-4154    ///
-4155    /// If the datagram was a stateless reset we may have failed to remove header protection
-4156    /// and thus `packet` may be `None`.
-4157    fn handle_packet(
-4158        &mut self,
-4159        now: Instant,
-4160        network_path: FourTuple,
-4161        path_id: PathId,
-4162        ecn: Option<EcnCodepoint>,
-4163        packet: Option<Packet>,
-4164        stateless_reset: bool,
-4165        mut qlog: QlogRecvPacket,
-4166    ) {
-4167        self.path_stats.for_path(path_id).udp_rx.ios += 1;
-4168
-4169        if let Some(ref packet) = packet {
-4170            trace!(
-4171                "got {:?} packet ({} bytes) from {} using id {}",
-4172                packet.header.space(),
-4173                packet.payload.len() + packet.header_data.len(),
-4174                network_path,
-4175                packet.header.dst_cid(),
-4176            );
-4177        }
-4178
-4179        let was_closed = self.state.is_closed();
-4180        let was_drained = self.state.is_drained();
-4181
-4182        // Now decrypt the packet payload in-place.
-4183        let decrypted = match packet {
-4184            None => Err(None),
-4185            Some(mut packet) => self
-4186                .decrypt_packet(now, path_id, &mut packet)
-4187                .map(move |number| (packet, number)),
-4188        };
-4189        let result = match decrypted {
-4190            _ if stateless_reset => {
-4191                debug!("got stateless reset");
-4192                Err(ConnectionError::Reset)
-4193            }
-4194            Err(Some(e)) => {
-4195                warn!("illegal packet: {}", e);
-4196                Err(e.into())
-4197            }
-4198            Err(None) => {
-4199                debug!("failed to authenticate packet");
-4200                self.authentication_failures += 1;
-4201                let integrity_limit = self
-4202                    .crypto_state
-4203                    .integrity_limit(self.highest_space)
-4204                    .unwrap();
-4205                if self.authentication_failures > integrity_limit {
-4206                    Err(TransportError::AEAD_LIMIT_REACHED("integrity limit violated").into())
-4207                } else {
-4208                    return;
-4209                }
-4210            }
-4211            Ok((packet, number)) => {
-4212                // We received an authenticated packet and decrypted it.
-4213                qlog.header(&packet.header, number, path_id);
-4214                let span = match number {
-4215                    Some(pn) => trace_span!("recv", space = ?packet.header.space(), pn),
-4216                    None => trace_span!("recv", space = ?packet.header.space()),
-4217                };
-4218                let _guard = span.enter();
-4219
-4220                // Now the packet is authenticated we do the migration during the
-4221                // handshake. See Handshake::allow_server_migration for details.
-4222                if self.is_handshaking() && network_path != self.path_data_mut(path_id).network_path
-4223                {
-4224                    if let Some(hs) = self.state.as_handshake()
-4225                        && hs.allow_server_migration
-4226                    {
-4227                        trace!(
-4228                            %network_path,
-4229                            prev = %self.path_data(path_id).network_path,
-4230                            "server migrated to new remote",
-4231                        );
-4232                        self.path_data_mut(path_id).network_path = network_path;
-4233                        self.qlog.emit_tuple_assigned(path_id, network_path, now);
-4234                    } else {
-4235                        debug!("discarding packet with unexpected remote during handshake");
-4236                        return;
-4237                    }
-4238                }
-4239
-4240                let dedup = self.spaces[packet.header.space()]
-4241                    .path_space_mut(path_id)
-4242                    .map(|pns| &mut pns.dedup);
-4243                if number.zip(dedup).is_some_and(|(n, d)| d.insert(n)) {
-4244                    debug!("discarding possible duplicate packet");
-4245                    self.qlog.emit_packet_received(qlog, now);
-4246                    return;
-4247                } else if self.state.is_handshake() && packet.header.is_short() {
-4248                    // TODO: SHOULD buffer these to improve reordering tolerance.
-4249                    trace!("dropping short packet during handshake");
-4250                    self.qlog.emit_packet_received(qlog, now);
-4251                    return;
-4252                } else {
-4253                    if let Header::Initial(InitialHeader { ref token, .. }) = packet.header
-4254                        && let Some(hs) = self.state.as_handshake()
-4255                        && self.side.is_server()
-4256                        && token != &hs.expected_token
-4257                    {
-4258                        // Clients must send the same retry token in every Initial. Initial
-4259                        // packets can be spoofed, so we discard rather than killing the
-4260                        // connection.
-4261                        warn!("discarding Initial with invalid retry token");
-4262                        self.qlog.emit_packet_received(qlog, now);
-4263                        return;
-4264                    }
-4265
-4266                    if !self.state.is_closed() {
-4267                        let spin = match packet.header {
-4268                            Header::Short { spin, .. } => spin,
-4269                            _ => false,
-4270                        };
-4271
-4272                        if self.side().is_server() && !self.abandoned_paths.contains(&path_id) {
-4273                            // Only the client is allowed to open paths
-4274                            self.ensure_path(path_id, network_path, now, number);
-4275                        }
-4276                        if self.paths.contains_key(&path_id) {
-4277                            self.on_packet_authenticated(
-4278                                now,
-4279                                packet.header.space(),
-4280                                path_id,
-4281                                ecn,
-4282                                number,
-4283                                spin,
-4284                                packet.header.is_1rtt(),
-4285                                &network_path,
-4286                            );
-4287                        }
-4288                    }
-4289
-4290                    let res = self.process_decrypted_packet(
-4291                        now,
-4292                        network_path,
-4293                        path_id,
-4294                        number,
-4295                        packet,
-4296                        &mut qlog,
-4297                    );
-4298
-4299                    self.qlog.emit_packet_received(qlog, now);
-4300                    res
-4301                }
-4302            }
-4303        };
-4304
-4305        // State transitions for error cases
-4306        if let Err(conn_err) = result {
-4307            match conn_err {
-4308                ConnectionError::ApplicationClosed(reason) => self.state.move_to_closed(reason),
-4309                ConnectionError::ConnectionClosed(reason) => self.state.move_to_closed(reason),
-4310                ConnectionError::Reset
-4311                | ConnectionError::TransportError(TransportError {
-4312                    code: TransportErrorCode::AEAD_LIMIT_REACHED,
-4313                    ..
-4314                }) => {
-4315                    self.state.move_to_drained(Some(conn_err));
-4316                }
-4317                ConnectionError::TimedOut => {
-4318                    unreachable!("timeouts aren't generated by packet processing");
-4319                }
-4320                ConnectionError::TransportError(err) => {
-4321                    debug!("closing connection due to transport error: {}", err);
-4322                    self.state.move_to_closed(err);
+3795    }
+3796
+3797    /// Resets both the [`ConnTimer::KeepAlive`] and [`PathTimer::PathKeepAlive`] timers
+3798    fn reset_keep_alive(&mut self, path_id: PathId, now: Instant) {
+3799        if !self.state.is_established() {
+3800            return;
+3801        }
+3802
+3803        if let Some(interval) = self.config.keep_alive_interval {
+3804            self.timers.set(
+3805                Timer::Conn(ConnTimer::KeepAlive),
+3806                now + interval,
+3807                self.qlog.with_time(now),
+3808            );
+3809        }
+3810
+3811        if let Some(interval) = self.path_data(path_id).keep_alive {
+3812            self.timers.set(
+3813                Timer::PerPath(path_id, PathTimer::PathKeepAlive),
+3814                now + interval,
+3815                self.qlog.with_time(now),
+3816            );
+3817        }
+3818    }
+3819
+3820    /// Sets the timer for when a previously issued CID should be retired next
+3821    fn reset_cid_retirement(&mut self, now: Instant) {
+3822        if let Some((_path, t)) = self.next_cid_retirement() {
+3823            self.timers.set(
+3824                Timer::Conn(ConnTimer::PushNewCid),
+3825                t,
+3826                self.qlog.with_time(now),
+3827            );
+3828        }
+3829    }
+3830
+3831    /// The next time when a previously issued CID should be retired
+3832    fn next_cid_retirement(&self) -> Option<(PathId, Instant)> {
+3833        self.local_cid_state
+3834            .iter()
+3835            .filter_map(|(path_id, cid_state)| cid_state.next_timeout().map(|t| (*path_id, t)))
+3836            .min_by_key(|(_path_id, timeout)| *timeout)
+3837    }
+3838
+3839    /// Handle the already-decrypted first packet from the client
+3840    ///
+3841    /// Decrypting the first packet in the `Endpoint` allows stateless packet handling to be more
+3842    /// efficient.
+3843    pub(crate) fn handle_first_packet(
+3844        &mut self,
+3845        now: Instant,
+3846        network_path: FourTuple,
+3847        ecn: Option<EcnCodepoint>,
+3848        packet_number: u64,
+3849        packet: InitialPacket,
+3850        remaining: Option<BytesMut>,
+3851    ) -> Result<(), ConnectionError> {
+3852        let span = trace_span!("first recv");
+3853        let _guard = span.enter();
+3854        debug_assert!(self.side.is_server());
+3855        let len = packet.header_data.len() + packet.payload.len();
+3856        let path_id = PathId::ZERO;
+3857        self.path_data_mut(path_id).total_recvd = len as u64;
+3858
+3859        if let Some(hs) = self.state.as_handshake_mut() {
+3860            hs.expected_token = packet.header.token.clone();
+3861        } else {
+3862            unreachable!("first packet must be delivered in Handshake state");
+3863        }
+3864
+3865        // The first packet is always on PathId::ZERO
+3866        self.on_packet_authenticated(
+3867            now,
+3868            SpaceKind::Initial,
+3869            path_id,
+3870            ecn,
+3871            Some(packet_number),
+3872            false,
+3873            false,
+3874            &network_path,
+3875        );
+3876
+3877        let packet: Packet = packet.into();
+3878
+3879        let mut qlog = QlogRecvPacket::new(len);
+3880        qlog.header(&packet.header, Some(packet_number), path_id);
+3881
+3882        self.process_decrypted_packet(
+3883            now,
+3884            network_path,
+3885            path_id,
+3886            Some(packet_number),
+3887            packet,
+3888            &mut qlog,
+3889        )?;
+3890        self.qlog.emit_packet_received(qlog, now);
+3891        if let Some(data) = remaining {
+3892            self.handle_coalesced(now, network_path, path_id, ecn, data);
+3893        }
+3894
+3895        self.qlog.emit_recovery_metrics(
+3896            path_id,
+3897            &mut self
+3898                .paths
+3899                .get_mut(&path_id)
+3900                .expect("path_id was supplied by the caller for an active path")
+3901                .data,
+3902            now,
+3903        );
+3904
+3905        Ok(())
+3906    }
+3907
+3908    fn init_0rtt(&mut self, now: Instant) {
+3909        let Some((header, packet)) = self.crypto_state.session.early_crypto() else {
+3910            return;
+3911        };
+3912        if self.side.is_client() {
+3913            match self.crypto_state.session.transport_parameters() {
+3914                Ok(params) => {
+3915                    let params = params
+3916                        .expect("crypto layer didn't supply transport parameters with ticket");
+3917                    // Certain values must not be cached
+3918                    let params = TransportParameters {
+3919                        initial_src_cid: None,
+3920                        original_dst_cid: None,
+3921                        preferred_address: None,
+3922                        retry_src_cid: None,
+3923                        stateless_reset_token: None,
+3924                        min_ack_delay: None,
+3925                        ack_delay_exponent: TransportParameters::default().ack_delay_exponent,
+3926                        max_ack_delay: TransportParameters::default().max_ack_delay,
+3927                        initial_max_path_id: None,
+3928                        ..params
+3929                    };
+3930                    self.set_peer_params(params);
+3931                    self.qlog.emit_peer_transport_params_restored(self, now);
+3932                }
+3933                Err(e) => {
+3934                    error!("session ticket has malformed transport parameters: {}", e);
+3935                    return;
+3936                }
+3937            }
+3938        }
+3939        trace!("0-RTT enabled");
+3940        self.crypto_state.enable_zero_rtt(header, packet);
+3941    }
+3942
+3943    fn read_crypto(
+3944        &mut self,
+3945        space: SpaceId,
+3946        crypto: &frame::Crypto,
+3947        payload_len: usize,
+3948    ) -> Result<(), TransportError> {
+3949        let expected = if !self.state.is_handshake() {
+3950            SpaceId::Data
+3951        } else if self.highest_space == SpaceKind::Initial {
+3952            SpaceId::Initial
+3953        } else {
+3954            // On the server, self.highest_space can be Data after receiving the client's first
+3955            // flight, but we expect Handshake CRYPTO until the handshake is complete.
+3956            SpaceId::Handshake
+3957        };
+3958        // We can't decrypt Handshake packets when highest_space is Initial, CRYPTO frames in 0-RTT
+3959        // packets are illegal, and we don't process 1-RTT packets until the handshake is
+3960        // complete. Therefore, we will never see CRYPTO data from a later-than-expected space.
+3961        debug_assert!(space <= expected, "received out-of-order CRYPTO data");
+3962
+3963        let end = crypto.offset + crypto.data.len() as u64;
+3964        if space < expected
+3965            && end
+3966                > self.crypto_state.spaces[space.kind()]
+3967                    .crypto_stream
+3968                    .bytes_read()
+3969        {
+3970            warn!(
+3971                "received new {:?} CRYPTO data when expecting {:?}",
+3972                space, expected
+3973            );
+3974            return Err(TransportError::PROTOCOL_VIOLATION(
+3975                "new data at unexpected encryption level",
+3976            ));
+3977        }
+3978
+3979        let crypto_space = &mut self.crypto_state.spaces[space.kind()];
+3980        let max = end.saturating_sub(crypto_space.crypto_stream.bytes_read());
+3981        if max > self.config.crypto_buffer_size as u64 {
+3982            return Err(TransportError::CRYPTO_BUFFER_EXCEEDED(""));
+3983        }
+3984
+3985        crypto_space
+3986            .crypto_stream
+3987            .insert(crypto.offset, crypto.data.clone(), payload_len);
+3988        while let Some(chunk) = crypto_space.crypto_stream.read(usize::MAX, true) {
+3989            trace!("consumed {} CRYPTO bytes", chunk.bytes.len());
+3990            if self.crypto_state.session.read_handshake(&chunk.bytes)? {
+3991                self.events.push_back(Event::HandshakeDataReady);
+3992            }
+3993        }
+3994
+3995        Ok(())
+3996    }
+3997
+3998    fn write_crypto(&mut self) {
+3999        loop {
+4000            let space = self.highest_space;
+4001            let mut outgoing = Vec::new();
+4002            if let Some(crypto) = self.crypto_state.session.write_handshake(&mut outgoing) {
+4003                match space {
+4004                    SpaceKind::Initial => {
+4005                        self.upgrade_crypto(SpaceKind::Handshake, crypto);
+4006                    }
+4007                    SpaceKind::Handshake => {
+4008                        self.upgrade_crypto(SpaceKind::Data, crypto);
+4009                    }
+4010                    SpaceKind::Data => unreachable!("got updated secrets during 1-RTT"),
+4011                }
+4012            }
+4013            if outgoing.is_empty() {
+4014                if space == self.highest_space {
+4015                    break;
+4016                } else {
+4017                    // Keys updated, check for more data to send
+4018                    continue;
+4019                }
+4020            }
+4021            let offset = self.crypto_state.spaces[space].crypto_offset;
+4022            let outgoing = Bytes::from(outgoing);
+4023            if let Some(hs) = self.state.as_handshake_mut()
+4024                && space == SpaceKind::Initial
+4025                && offset == 0
+4026                && self.side.is_client()
+4027            {
+4028                hs.client_hello = Some(outgoing.clone());
+4029            }
+4030            self.crypto_state.spaces[space].crypto_offset += outgoing.len() as u64;
+4031            trace!("wrote {} {:?} CRYPTO bytes", outgoing.len(), space);
+4032            self.spaces[space].pending.crypto.push_back(frame::Crypto {
+4033                offset,
+4034                data: outgoing,
+4035            });
+4036        }
+4037    }
+4038
+4039    /// Switch to stronger cryptography during handshake
+4040    fn upgrade_crypto(&mut self, space: SpaceKind, crypto: Keys) {
+4041        debug_assert!(
+4042            !self.crypto_state.has_keys(space.encryption_level()),
+4043            "already reached packet space {space:?}"
+4044        );
+4045        trace!("{:?} keys ready", space);
+4046        if space == SpaceKind::Data {
+4047            // Precompute the first key update
+4048            self.crypto_state.next_crypto = Some(
+4049                self.crypto_state
+4050                    .session
+4051                    .next_1rtt_keys()
+4052                    .expect("handshake should be complete"),
+4053            );
+4054        }
+4055
+4056        self.crypto_state.spaces[space].keys = Some(crypto);
+4057        debug_assert!(space > self.highest_space);
+4058        self.highest_space = space;
+4059        if space == SpaceKind::Data && self.side.is_client() {
+4060            // Discard 0-RTT keys because 1-RTT keys are available.
+4061            self.crypto_state.discard_zero_rtt();
+4062        }
+4063    }
+4064
+4065    fn discard_space(&mut self, now: Instant, space: SpaceKind) {
+4066        debug_assert!(space != SpaceKind::Data);
+4067        trace!("discarding {:?} keys", space);
+4068        if space == SpaceKind::Initial {
+4069            // No longer needed
+4070            if let ConnectionSide::Client { token, .. } = &mut self.side {
+4071                *token = Bytes::new();
+4072            }
+4073        }
+4074        self.crypto_state.spaces[space].keys = None;
+4075        let space = &mut self.spaces[space];
+4076        let pns = space.for_path(PathId::ZERO);
+4077        pns.time_of_last_ack_eliciting_packet = None;
+4078        pns.loss_time = None;
+4079        pns.loss_probes = 0;
+4080        let sent_packets = mem::take(&mut pns.sent_packets);
+4081        let path = self
+4082            .paths
+4083            .get_mut(&PathId::ZERO)
+4084            .expect("PathId::ZERO is alive while Initial/Handshake spaces exist");
+4085        for (_, packet) in sent_packets.into_iter() {
+4086            path.data.remove_in_flight(&packet);
+4087        }
+4088
+4089        self.set_loss_detection_timer(now, PathId::ZERO)
+4090    }
+4091
+4092    fn handle_coalesced(
+4093        &mut self,
+4094        now: Instant,
+4095        network_path: FourTuple,
+4096        path_id: PathId,
+4097        ecn: Option<EcnCodepoint>,
+4098        data: BytesMut,
+4099    ) {
+4100        self.path_data_mut(path_id)
+4101            .inc_total_recvd(data.len() as u64);
+4102        let mut remaining = Some(data);
+4103        let cid_len = self
+4104            .local_cid_state
+4105            .values()
+4106            .map(|cid_state| cid_state.cid_len())
+4107            .next()
+4108            .expect("one cid_state must exist");
+4109        while let Some(data) = remaining {
+4110            match PartialDecode::new(
+4111                data,
+4112                &FixedLengthConnectionIdParser::new(cid_len),
+4113                &[self.version],
+4114                self.endpoint_config.grease_quic_bit,
+4115            ) {
+4116                Ok((partial_decode, rest)) => {
+4117                    remaining = rest;
+4118                    self.handle_decode(now, network_path, path_id, ecn, partial_decode);
+4119                }
+4120                Err(e) => {
+4121                    trace!("malformed header: {}", e);
+4122                    return;
+4123                }
+4124            }
+4125        }
+4126    }
+4127
+4128    /// Decrypts the packet and processes the payload.
+4129    ///
+4130    /// Processes the entire packet, starting with removing header protection, then handling
+4131    /// a stateless reset if needed, and decrypting and processing the frames in the payload
+4132    /// if not a stateless reset.
+4133    fn handle_decode(
+4134        &mut self,
+4135        now: Instant,
+4136        network_path: FourTuple,
+4137        path_id: PathId,
+4138        ecn: Option<EcnCodepoint>,
+4139        partial_decode: PartialDecode,
+4140    ) {
+4141        let qlog = QlogRecvPacket::new(partial_decode.len());
+4142        if let Some(decoded) = self
+4143            .crypto_state
+4144            .unprotect_header(partial_decode, self.peer_params.stateless_reset_token)
+4145        {
+4146            self.handle_packet(
+4147                now,
+4148                network_path,
+4149                path_id,
+4150                ecn,
+4151                decoded.packet,
+4152                decoded.stateless_reset,
+4153                qlog,
+4154            );
+4155        }
+4156    }
+4157
+4158    /// Handles a packet with header protection removed.
+4159    ///
+4160    /// The packet body is still encrypted at this point.
+4161    ///
+4162    /// If the datagram was a stateless reset we may have failed to remove header protection
+4163    /// and thus `packet` may be `None`.
+4164    fn handle_packet(
+4165        &mut self,
+4166        now: Instant,
+4167        network_path: FourTuple,
+4168        path_id: PathId,
+4169        ecn: Option<EcnCodepoint>,
+4170        packet: Option<Packet>,
+4171        stateless_reset: bool,
+4172        mut qlog: QlogRecvPacket,
+4173    ) {
+4174        self.path_stats.for_path(path_id).udp_rx.ios += 1;
+4175
+4176        if let Some(ref packet) = packet {
+4177            trace!(
+4178                "got {:?} packet ({} bytes) from {} using id {}",
+4179                packet.header.space(),
+4180                packet.payload.len() + packet.header_data.len(),
+4181                network_path,
+4182                packet.header.dst_cid(),
+4183            );
+4184        }
+4185
+4186        let was_closed = self.state.is_closed();
+4187        let was_drained = self.state.is_drained();
+4188
+4189        // Now decrypt the packet payload in-place.
+4190        let decrypted = match packet {
+4191            None => Err(None),
+4192            Some(mut packet) => self
+4193                .decrypt_packet(now, path_id, &mut packet)
+4194                .map(move |number| (packet, number)),
+4195        };
+4196        let result = match decrypted {
+4197            _ if stateless_reset => {
+4198                debug!("got stateless reset");
+4199                Err(ConnectionError::Reset)
+4200            }
+4201            Err(Some(e)) => {
+4202                warn!("illegal packet: {}", e);
+4203                Err(e.into())
+4204            }
+4205            Err(None) => {
+4206                debug!("failed to authenticate packet");
+4207                self.authentication_failures += 1;
+4208                let integrity_limit = self
+4209                    .crypto_state
+4210                    .integrity_limit(self.highest_space)
+4211                    .unwrap();
+4212                if self.authentication_failures > integrity_limit {
+4213                    Err(TransportError::AEAD_LIMIT_REACHED("integrity limit violated").into())
+4214                } else {
+4215                    return;
+4216                }
+4217            }
+4218            Ok((packet, number)) => {
+4219                // We received an authenticated packet and decrypted it.
+4220                qlog.header(&packet.header, number, path_id);
+4221                let span = match number {
+4222                    Some(pn) => trace_span!("recv", space = ?packet.header.space(), pn),
+4223                    None => trace_span!("recv", space = ?packet.header.space()),
+4224                };
+4225                let _guard = span.enter();
+4226
+4227                // Now the packet is authenticated we do the migration during the
+4228                // handshake. See Handshake::allow_server_migration for details.
+4229                if self.is_handshaking() && network_path != self.path_data_mut(path_id).network_path
+4230                {
+4231                    if let Some(hs) = self.state.as_handshake()
+4232                        && hs.allow_server_migration
+4233                    {
+4234                        trace!(
+4235                            %network_path,
+4236                            prev = %self.path_data(path_id).network_path,
+4237                            "server migrated to new remote",
+4238                        );
+4239                        self.path_data_mut(path_id).network_path = network_path;
+4240                        self.qlog.emit_tuple_assigned(path_id, network_path, now);
+4241                    } else {
+4242                        debug!("discarding packet with unexpected remote during handshake");
+4243                        return;
+4244                    }
+4245                }
+4246
+4247                let dedup = self.spaces[packet.header.space()]
+4248                    .path_space_mut(path_id)
+4249                    .map(|pns| &mut pns.dedup);
+4250                if number.zip(dedup).is_some_and(|(n, d)| d.insert(n)) {
+4251                    debug!("discarding possible duplicate packet");
+4252                    self.qlog.emit_packet_received(qlog, now);
+4253                    return;
+4254                } else if self.state.is_handshake() && packet.header.is_short() {
+4255                    // TODO: SHOULD buffer these to improve reordering tolerance.
+4256                    trace!("dropping short packet during handshake");
+4257                    self.qlog.emit_packet_received(qlog, now);
+4258                    return;
+4259                } else {
+4260                    if let Header::Initial(InitialHeader { ref token, .. }) = packet.header
+4261                        && let Some(hs) = self.state.as_handshake()
+4262                        && self.side.is_server()
+4263                        && token != &hs.expected_token
+4264                    {
+4265                        // Clients must send the same retry token in every Initial. Initial
+4266                        // packets can be spoofed, so we discard rather than killing the
+4267                        // connection.
+4268                        warn!("discarding Initial with invalid retry token");
+4269                        self.qlog.emit_packet_received(qlog, now);
+4270                        return;
+4271                    }
+4272
+4273                    if !self.state.is_closed() {
+4274                        let spin = match packet.header {
+4275                            Header::Short { spin, .. } => spin,
+4276                            _ => false,
+4277                        };
+4278
+4279                        if self.side().is_server() && !self.abandoned_paths.contains(&path_id) {
+4280                            // Only the client is allowed to open paths
+4281                            self.ensure_path(path_id, network_path, now, number);
+4282                        }
+4283                        if self.paths.contains_key(&path_id) {
+4284                            self.on_packet_authenticated(
+4285                                now,
+4286                                packet.header.space(),
+4287                                path_id,
+4288                                ecn,
+4289                                number,
+4290                                spin,
+4291                                packet.header.is_1rtt(),
+4292                                &network_path,
+4293                            );
+4294                        }
+4295                    }
+4296
+4297                    let res = self.process_decrypted_packet(
+4298                        now,
+4299                        network_path,
+4300                        path_id,
+4301                        number,
+4302                        packet,
+4303                        &mut qlog,
+4304                    );
+4305
+4306                    self.qlog.emit_packet_received(qlog, now);
+4307                    res
+4308                }
+4309            }
+4310        };
+4311
+4312        // State transitions for error cases
+4313        if let Err(conn_err) = result {
+4314            match conn_err {
+4315                ConnectionError::ApplicationClosed(reason) => self.state.move_to_closed(reason),
+4316                ConnectionError::ConnectionClosed(reason) => self.state.move_to_closed(reason),
+4317                ConnectionError::Reset
+4318                | ConnectionError::TransportError(TransportError {
+4319                    code: TransportErrorCode::AEAD_LIMIT_REACHED,
+4320                    ..
+4321                }) => {
+4322                    self.state.move_to_drained(Some(conn_err));
 4323                }
-4324                ConnectionError::VersionMismatch => {
-4325                    self.state.move_to_draining(Some(conn_err));
+4324                ConnectionError::TimedOut => {
+4325                    unreachable!("timeouts aren't generated by packet processing");
 4326                }
-4327                ConnectionError::LocallyClosed => {
-4328                    unreachable!("LocallyClosed isn't generated by packet processing");
-4329                }
-4330                ConnectionError::CidsExhausted => {
-4331                    unreachable!("CidsExhausted isn't generated by packet processing");
-4332                }
-4333            };
-4334        }
-4335
-4336        if !was_closed && self.state.is_closed() {
-4337            self.close_common();
-4338            if !self.state.is_drained() {
-4339                self.set_close_timer(now);
-4340            }
+4327                ConnectionError::TransportError(err) => {
+4328                    debug!("closing connection due to transport error: {}", err);
+4329                    self.state.move_to_closed(err);
+4330                }
+4331                ConnectionError::VersionMismatch => {
+4332                    self.state.move_to_draining(Some(conn_err));
+4333                }
+4334                ConnectionError::LocallyClosed => {
+4335                    unreachable!("LocallyClosed isn't generated by packet processing");
+4336                }
+4337                ConnectionError::CidsExhausted => {
+4338                    unreachable!("CidsExhausted isn't generated by packet processing");
+4339                }
+4340            };
 4341        }
-4342        if !was_drained && self.state.is_drained() {
-4343            self.endpoint_events.push_back(EndpointEventInner::Drained);
-4344            // Close timer may have been started previously, e.g. if we sent a close and got a
-4345            // stateless reset in response
-4346            self.timers
-4347                .stop(Timer::Conn(ConnTimer::Close), self.qlog.with_time(now));
+4342
+4343        if !was_closed && self.state.is_closed() {
+4344            self.close_common();
+4345            if !self.state.is_drained() {
+4346                self.set_close_timer(now);
+4347            }
 4348        }
-4349
-4350        // Transmit CONNECTION_CLOSE if necessary.
-4351        //
-4352        // If we received a valid packet and we are in the closed state we should respond
-4353        // with a CONNECTION_CLOSE frame.
-4354        // TODO: This SHOULD be rate-limited according to §10.2.1 of QUIC-TRANSPORT, but
-4355        //    that does not yet happen. This is triggered by each received packet.
-4356        if matches!(self.state.as_type(), StateType::Closed) {
-4357            // From https://www.rfc-editor.org/rfc/rfc9000.html#section-10.2.1-7
-4358            //
-4359            // While in the closing state we must either:
-4360            // - discard packets coming from an un-validated remote OR
-4361            // - ensure we do not send more than 3 times the received data
-4362            //
-4363            // Doing the 2nd would mean we would be able to send CONNECTION_CLOSE to a peer
-4364            // who was (involuntary) migrated just at the time we initiated immediate
-4365            // close. It is a lot more work though. So while we would like to do this for
-4366            // now we only do 1.
-4367            //
-4368            // Another shortcoming of the current implementation is that when we have a
-4369            // previous PathData which is validated and the remote matches that path, we
-4370            // should schedule CONNECTION_CLOSE on that path. However currently we can not
-4371            // schedule such a packet. We should also fix this some day. This makes us
-4372            // vulnerable to an attacker faking a migration at the right time and then we'd
-4373            // be unable to send the CONNECTION_CLOSE to the real remote.
-4374            if self
-4375                .paths
-4376                .get(&path_id)
-4377                .map(|p| p.data.validated && p.data.network_path == network_path)
-4378                .unwrap_or(false)
-4379            {
-4380                self.connection_close_pending = true;
-4381            }
-4382        }
-4383    }
-4384
-4385    fn process_decrypted_packet(
-4386        &mut self,
-4387        now: Instant,
-4388        network_path: FourTuple,
-4389        path_id: PathId,
-4390        number: Option<u64>,
-4391        packet: Packet,
-4392        qlog: &mut QlogRecvPacket,
-4393    ) -> Result<(), ConnectionError> {
-4394        if !self.paths.contains_key(&path_id) {
-4395            // There is a chance this is a server side, first (for this path) packet, which would
-4396            // be a protocol violation. It's more likely, however, that this is a packet of a
-4397            // pruned path
-4398            trace!(%path_id, ?number, "discarding packet for unknown path");
-4399            return Ok(());
-4400        }
-4401        let state = match self.state.as_type() {
-4402            StateType::Established => {
-4403                match packet.header.space() {
-4404                    SpaceKind::Data => self.process_payload(
-4405                        now,
-4406                        network_path,
-4407                        path_id,
-4408                        number.unwrap(),
-4409                        packet,
-4410                        qlog,
-4411                    )?,
-4412                    _ if packet.header.has_frames() => {
-4413                        self.process_early_payload(now, path_id, packet, qlog)?
-4414                    }
-4415                    _ => {
-4416                        trace!("discarding unexpected pre-handshake packet");
-4417                    }
-4418                }
-4419                return Ok(());
-4420            }
-4421            StateType::Closed => {
-4422                for result in frame::Iter::new(packet.payload.freeze())? {
-4423                    let frame = match result {
-4424                        Ok(frame) => frame,
-4425                        Err(err) => {
-4426                            debug!("frame decoding error: {err:?}");
-4427                            continue;
-4428                        }
-4429                    };
-4430                    qlog.frame(&frame);
-4431
-4432                    if let Frame::Padding = frame {
-4433                        continue;
-4434                    };
-4435
-4436                    self.path_stats
-4437                        .for_path(path_id)
-4438                        .frame_rx
-4439                        .record(frame.ty());
-4440
-4441                    if let Frame::Close(_error) = frame {
-4442                        self.state.move_to_draining(None);
-4443                        break;
-4444                    }
-4445                }
-4446                return Ok(());
-4447            }
-4448            StateType::Draining | StateType::Drained => return Ok(()),
-4449            StateType::Handshake => self.state.as_handshake_mut().expect("checked"),
-4450        };
-4451
-4452        match packet.header {
-4453            Header::Retry {
-4454                src_cid: remote_cid,
-4455                ..
-4456            } => {
-4457                debug_assert_eq!(path_id, PathId::ZERO);
-4458                if self.side.is_server() {
-4459                    return Err(TransportError::PROTOCOL_VIOLATION("client sent Retry").into());
-4460                }
-4461
-4462                let is_valid_retry = self
-4463                    .remote_cids
-4464                    .get(&path_id)
-4465                    .map(|cids| cids.active())
-4466                    .map(|orig_dst_cid| {
-4467                        self.crypto_state.session.is_valid_retry(
-4468                            orig_dst_cid,
-4469                            &packet.header_data,
-4470                            &packet.payload,
-4471                        )
-4472                    })
-4473                    .unwrap_or_default();
-4474                if self.total_authed_packets > 1
-4475                            || packet.payload.len() <= 16 // token + 16 byte tag
-4476                            || !is_valid_retry
-4477                {
-4478                    trace!("discarding invalid Retry");
-4479                    // - After the client has received and processed an Initial or Retry
-4480                    //   packet from the server, it MUST discard any subsequent Retry
-4481                    //   packets that it receives.
-4482                    // - A client MUST discard a Retry packet with a zero-length Retry Token
-4483                    //   field.
-4484                    // - Clients MUST discard Retry packets that have a Retry Integrity Tag
-4485                    //   that cannot be validated
-4486                    return Ok(());
-4487                }
-4488
-4489                trace!("retrying with CID {}", remote_cid);
-4490                let client_hello = state.client_hello.take().unwrap();
-4491                self.retry_src_cid = Some(remote_cid);
-4492                self.remote_cids
-4493                    .get_mut(&path_id)
-4494                    .expect("PathId::ZERO not yet abandoned, is_valid_retry would have been false")
-4495                    .update_initial_cid(remote_cid);
-4496                self.remote_handshake_cid = remote_cid;
-4497
-4498                let space = &mut self.spaces[SpaceId::Initial];
-4499                if let Some(info) = space.for_path(PathId::ZERO).take(0) {
-4500                    self.on_packet_acked(now, PathId::ZERO, 0, info);
-4501                };
-4502
-4503                self.discard_space(now, SpaceKind::Initial); // Make sure we clean up after
-4504                // any retransmitted Initials
-4505                let crypto_space = &mut self.crypto_state.spaces[SpaceKind::Initial];
-4506                crypto_space.keys = Some(
-4507                    self.crypto_state
-4508                        .session
-4509                        .initial_keys(remote_cid, self.side.side()),
-4510                );
-4511                crypto_space.crypto_offset = client_hello.len() as u64;
-4512
-4513                let next_pn = self.spaces[SpaceId::Initial]
-4514                    .for_path(path_id)
-4515                    .next_packet_number;
-4516                self.spaces[SpaceId::Initial] = {
-4517                    let mut space = PacketSpace::new(now, SpaceId::Initial, &mut self.rng);
-4518                    space.for_path(path_id).next_packet_number = next_pn;
-4519                    space.pending.crypto.push_back(frame::Crypto {
-4520                        offset: 0,
-4521                        data: client_hello,
-4522                    });
-4523                    space
-4524                };
-4525
-4526                // Retransmit all 0-RTT data
-4527                let zero_rtt = mem::take(
-4528                    &mut self.spaces[SpaceId::Data]
-4529                        .for_path(PathId::ZERO)
-4530                        .sent_packets,
-4531                );
-4532                for (_, info) in zero_rtt.into_iter() {
-4533                    self.paths
-4534                        .get_mut(&PathId::ZERO)
-4535                        .unwrap()
-4536                        .remove_in_flight(&info);
-4537                    self.spaces[SpaceId::Data].pending |= info.retransmits;
-4538                }
-4539                self.streams.retransmit_all_for_0rtt();
-4540
-4541                let token_len = packet.payload.len() - 16;
-4542                let ConnectionSide::Client { ref mut token, .. } = self.side else {
-4543                    unreachable!("we already short-circuited if we're server");
-4544                };
-4545                *token = packet.payload.freeze().split_to(token_len);
-4546
-4547                self.state = State::handshake(state::Handshake {
-4548                    expected_token: Bytes::new(),
-4549                    remote_cid_set: false,
-4550                    client_hello: None,
-4551                    allow_server_migration: true,
-4552                });
-4553                Ok(())
-4554            }
-4555            Header::Long {
-4556                ty: LongType::Handshake,
-4557                src_cid: remote_cid,
-4558                dst_cid: local_cid,
-4559                ..
-4560            } => {
-4561                debug_assert_eq!(path_id, PathId::ZERO);
-4562                if remote_cid != self.remote_handshake_cid {
-4563                    debug!(
-4564                        "discarding packet with mismatched remote CID: {} != {}",
-4565                        self.remote_handshake_cid, remote_cid
-4566                    );
-4567                    return Ok(());
-4568                }
-4569                self.on_path_validated(path_id);
-4570
-4571                self.process_early_payload(now, path_id, packet, qlog)?;
-4572                if self.state.is_closed() {
-4573                    return Ok(());
-4574                }
-4575
-4576                if self.crypto_state.session.is_handshaking() {
-4577                    trace!("handshake ongoing");
-4578                    return Ok(());
-4579                }
-4580
-4581                if self.side.is_client() {
-4582                    // Client-only because server params were set from the client's Initial
-4583                    let params = self
-4584                        .crypto_state
-4585                        .session
-4586                        .transport_parameters()?
-4587                        .ok_or_else(|| {
-4588                            TransportError::new(
-4589                                TransportErrorCode::crypto(0x6d),
-4590                                "transport parameters missing".to_owned(),
-4591                            )
-4592                        })?;
-4593
-4594                    if self.has_0rtt() {
-4595                        if !self.crypto_state.session.early_data_accepted().unwrap() {
-4596                            debug_assert!(self.side.is_client());
-4597                            debug!("0-RTT rejected");
-4598                            self.crypto_state.accepted_0rtt = false;
-4599                            self.streams.zero_rtt_rejected();
+4349        if !was_drained && self.state.is_drained() {
+4350            self.endpoint_events.push_back(EndpointEventInner::Drained);
+4351            // Close timer may have been started previously, e.g. if we sent a close and got a
+4352            // stateless reset in response
+4353            self.timers
+4354                .stop(Timer::Conn(ConnTimer::Close), self.qlog.with_time(now));
+4355        }
+4356
+4357        // Transmit CONNECTION_CLOSE if necessary.
+4358        //
+4359        // If we received a valid packet and we are in the closed state we should respond
+4360        // with a CONNECTION_CLOSE frame.
+4361        // TODO: This SHOULD be rate-limited according to §10.2.1 of QUIC-TRANSPORT, but
+4362        //    that does not yet happen. This is triggered by each received packet.
+4363        if matches!(self.state.as_type(), StateType::Closed) {
+4364            // From https://www.rfc-editor.org/rfc/rfc9000.html#section-10.2.1-7
+4365            //
+4366            // While in the closing state we must either:
+4367            // - discard packets coming from an un-validated remote OR
+4368            // - ensure we do not send more than 3 times the received data
+4369            //
+4370            // Doing the 2nd would mean we would be able to send CONNECTION_CLOSE to a peer
+4371            // who was (involuntary) migrated just at the time we initiated immediate
+4372            // close. It is a lot more work though. So while we would like to do this for
+4373            // now we only do 1.
+4374            //
+4375            // Another shortcoming of the current implementation is that when we have a
+4376            // previous PathData which is validated and the remote matches that path, we
+4377            // should schedule CONNECTION_CLOSE on that path. However currently we can not
+4378            // schedule such a packet. We should also fix this some day. This makes us
+4379            // vulnerable to an attacker faking a migration at the right time and then we'd
+4380            // be unable to send the CONNECTION_CLOSE to the real remote.
+4381            if self
+4382                .paths
+4383                .get(&path_id)
+4384                .map(|p| p.data.validated && p.data.network_path == network_path)
+4385                .unwrap_or(false)
+4386            {
+4387                self.connection_close_pending = true;
+4388            }
+4389        }
+4390    }
+4391
+4392    fn process_decrypted_packet(
+4393        &mut self,
+4394        now: Instant,
+4395        network_path: FourTuple,
+4396        path_id: PathId,
+4397        number: Option<u64>,
+4398        packet: Packet,
+4399        qlog: &mut QlogRecvPacket,
+4400    ) -> Result<(), ConnectionError> {
+4401        if !self.paths.contains_key(&path_id) {
+4402            // There is a chance this is a server side, first (for this path) packet, which would
+4403            // be a protocol violation. It's more likely, however, that this is a packet of a
+4404            // pruned path
+4405            trace!(%path_id, ?number, "discarding packet for unknown path");
+4406            return Ok(());
+4407        }
+4408        let state = match self.state.as_type() {
+4409            StateType::Established => {
+4410                match packet.header.space() {
+4411                    SpaceKind::Data => self.process_payload(
+4412                        now,
+4413                        network_path,
+4414                        path_id,
+4415                        number.unwrap(),
+4416                        packet,
+4417                        qlog,
+4418                    )?,
+4419                    _ if packet.header.has_frames() => {
+4420                        self.process_early_payload(now, path_id, packet, qlog)?
+4421                    }
+4422                    _ => {
+4423                        trace!("discarding unexpected pre-handshake packet");
+4424                    }
+4425                }
+4426                return Ok(());
+4427            }
+4428            StateType::Closed => {
+4429                for result in frame::Iter::new(packet.payload.freeze())? {
+4430                    let frame = match result {
+4431                        Ok(frame) => frame,
+4432                        Err(err) => {
+4433                            debug!("frame decoding error: {err:?}");
+4434                            continue;
+4435                        }
+4436                    };
+4437                    qlog.frame(&frame);
+4438
+4439                    if let Frame::Padding = frame {
+4440                        continue;
+4441                    };
+4442
+4443                    self.path_stats
+4444                        .for_path(path_id)
+4445                        .frame_rx
+4446                        .record(frame.ty());
+4447
+4448                    if let Frame::Close(_error) = frame {
+4449                        self.state.move_to_draining(None);
+4450                        break;
+4451                    }
+4452                }
+4453                return Ok(());
+4454            }
+4455            StateType::Draining | StateType::Drained => return Ok(()),
+4456            StateType::Handshake => self.state.as_handshake_mut().expect("checked"),
+4457        };
+4458
+4459        match packet.header {
+4460            Header::Retry {
+4461                src_cid: remote_cid,
+4462                ..
+4463            } => {
+4464                debug_assert_eq!(path_id, PathId::ZERO);
+4465                if self.side.is_server() {
+4466                    return Err(TransportError::PROTOCOL_VIOLATION("client sent Retry").into());
+4467                }
+4468
+4469                let is_valid_retry = self
+4470                    .remote_cids
+4471                    .get(&path_id)
+4472                    .map(|cids| cids.active())
+4473                    .map(|orig_dst_cid| {
+4474                        self.crypto_state.session.is_valid_retry(
+4475                            orig_dst_cid,
+4476                            &packet.header_data,
+4477                            &packet.payload,
+4478                        )
+4479                    })
+4480                    .unwrap_or_default();
+4481                if self.total_authed_packets > 1
+4482                            || packet.payload.len() <= 16 // token + 16 byte tag
+4483                            || !is_valid_retry
+4484                {
+4485                    trace!("discarding invalid Retry");
+4486                    // - After the client has received and processed an Initial or Retry
+4487                    //   packet from the server, it MUST discard any subsequent Retry
+4488                    //   packets that it receives.
+4489                    // - A client MUST discard a Retry packet with a zero-length Retry Token
+4490                    //   field.
+4491                    // - Clients MUST discard Retry packets that have a Retry Integrity Tag
+4492                    //   that cannot be validated
+4493                    return Ok(());
+4494                }
+4495
+4496                trace!("retrying with CID {}", remote_cid);
+4497                let client_hello = state.client_hello.take().unwrap();
+4498                self.retry_src_cid = Some(remote_cid);
+4499                self.remote_cids
+4500                    .get_mut(&path_id)
+4501                    .expect("PathId::ZERO not yet abandoned, is_valid_retry would have been false")
+4502                    .update_initial_cid(remote_cid);
+4503                self.remote_handshake_cid = remote_cid;
+4504
+4505                let space = &mut self.spaces[SpaceId::Initial];
+4506                if let Some(info) = space.for_path(PathId::ZERO).take(0) {
+4507                    self.on_packet_acked(now, PathId::ZERO, 0, info);
+4508                };
+4509
+4510                self.discard_space(now, SpaceKind::Initial); // Make sure we clean up after
+4511                // any retransmitted Initials
+4512                let crypto_space = &mut self.crypto_state.spaces[SpaceKind::Initial];
+4513                crypto_space.keys = Some(
+4514                    self.crypto_state
+4515                        .session
+4516                        .initial_keys(remote_cid, self.side.side()),
+4517                );
+4518                crypto_space.crypto_offset = client_hello.len() as u64;
+4519
+4520                let next_pn = self.spaces[SpaceId::Initial]
+4521                    .for_path(path_id)
+4522                    .next_packet_number;
+4523                self.spaces[SpaceId::Initial] = {
+4524                    let mut space = PacketSpace::new(now, SpaceId::Initial, &mut self.rng);
+4525                    space.for_path(path_id).next_packet_number = next_pn;
+4526                    space.pending.crypto.push_back(frame::Crypto {
+4527                        offset: 0,
+4528                        data: client_hello,
+4529                    });
+4530                    space
+4531                };
+4532
+4533                // Retransmit all 0-RTT data
+4534                let zero_rtt = mem::take(
+4535                    &mut self.spaces[SpaceId::Data]
+4536                        .for_path(PathId::ZERO)
+4537                        .sent_packets,
+4538                );
+4539                for (_, info) in zero_rtt.into_iter() {
+4540                    self.paths
+4541                        .get_mut(&PathId::ZERO)
+4542                        .unwrap()
+4543                        .remove_in_flight(&info);
+4544                    self.spaces[SpaceId::Data].pending |= info.retransmits;
+4545                }
+4546                self.streams.retransmit_all_for_0rtt();
+4547
+4548                let token_len = packet.payload.len() - 16;
+4549                let ConnectionSide::Client { ref mut token, .. } = self.side else {
+4550                    unreachable!("we already short-circuited if we're server");
+4551                };
+4552                *token = packet.payload.freeze().split_to(token_len);
+4553
+4554                self.state = State::handshake(state::Handshake {
+4555                    expected_token: Bytes::new(),
+4556                    remote_cid_set: false,
+4557                    client_hello: None,
+4558                    allow_server_migration: true,
+4559                });
+4560                Ok(())
+4561            }
+4562            Header::Long {
+4563                ty: LongType::Handshake,
+4564                src_cid: remote_cid,
+4565                dst_cid: local_cid,
+4566                ..
+4567            } => {
+4568                debug_assert_eq!(path_id, PathId::ZERO);
+4569                if remote_cid != self.remote_handshake_cid {
+4570                    debug!(
+4571                        "discarding packet with mismatched remote CID: {} != {}",
+4572                        self.remote_handshake_cid, remote_cid
+4573                    );
+4574                    return Ok(());
+4575                }
+4576                self.on_path_validated(path_id);
+4577
+4578                self.process_early_payload(now, path_id, packet, qlog)?;
+4579                if self.state.is_closed() {
+4580                    return Ok(());
+4581                }
+4582
+4583                if self.crypto_state.session.is_handshaking() {
+4584                    trace!("handshake ongoing");
+4585                    return Ok(());
+4586                }
+4587
+4588                if self.side.is_client() {
+4589                    // Client-only because server params were set from the client's Initial
+4590                    let params = self
+4591                        .crypto_state
+4592                        .session
+4593                        .transport_parameters()?
+4594                        .ok_or_else(|| {
+4595                            TransportError::new(
+4596                                TransportErrorCode::crypto(0x6d),
+4597                                "transport parameters missing".to_owned(),
+4598                            )
+4599                        })?;
 4600
-4601                            // Discard already-queued frames
-4602                            self.spaces[SpaceId::Data].pending = Retransmits::default();
-4603
-4604                            // Discard 0-RTT packets
-4605                            let sent_packets = mem::take(
-4606                                &mut self.spaces[SpaceId::Data].for_path(path_id).sent_packets,
-4607                            );
-4608                            for (_, packet) in sent_packets.into_iter() {
-4609                                self.paths
-4610                                    .get_mut(&path_id)
-4611                                    .unwrap()
-4612                                    .remove_in_flight(&packet);
-4613                            }
-4614                        } else {
-4615                            self.crypto_state.accepted_0rtt = true;
-4616                            params.validate_resumption_from(&self.peer_params)?;
-4617                        }
-4618                    }
-4619                    if let Some(token) = params.stateless_reset_token {
-4620                        let remote = self.path_data(path_id).network_path.remote;
-4621                        debug_assert!(!self.state.is_drained()); // requirement for endpoint events, checked above
-4622                        self.endpoint_events
-4623                            .push_back(EndpointEventInner::ResetToken(path_id, remote, token));
-4624                    }
-4625                    self.handle_peer_params(params, local_cid, remote_cid, now)?;
-4626                    self.issue_first_cids(now);
-4627                } else {
-4628                    // Server-only
-4629                    self.spaces[SpaceId::Data].pending.handshake_done = true;
-4630                    self.discard_space(now, SpaceKind::Handshake);
-4631                    self.events.push_back(Event::HandshakeConfirmed);
-4632                    trace!("handshake confirmed");
-4633                }
-4634
-4635                self.events.push_back(Event::Connected);
-4636                self.state.move_to_established();
-4637                trace!("established");
-4638
-4639                // Multipath can only be enabled after the state has reached Established.
-4640                // So this can not happen any earlier.
-4641                self.issue_first_path_cids(now);
-4642                Ok(())
-4643            }
-4644            Header::Initial(InitialHeader {
-4645                src_cid: remote_cid,
-4646                dst_cid: local_cid,
-4647                ..
-4648            }) => {
-4649                debug_assert_eq!(path_id, PathId::ZERO);
-4650                if !state.remote_cid_set {
-4651                    trace!("switching remote CID to {}", remote_cid);
-4652                    let mut state = state.clone();
-4653                    self.remote_cids
-4654                        .get_mut(&path_id)
-4655                        .expect("PathId::ZERO not yet abandoned")
-4656                        .update_initial_cid(remote_cid);
-4657                    self.remote_handshake_cid = remote_cid;
-4658                    self.original_remote_cid = remote_cid;
-4659                    state.remote_cid_set = true;
-4660                    self.state.move_to_handshake(state);
-4661                } else if remote_cid != self.remote_handshake_cid {
-4662                    debug!(
-4663                        "discarding packet with mismatched remote CID: {} != {}",
-4664                        self.remote_handshake_cid, remote_cid
-4665                    );
-4666                    return Ok(());
-4667                }
-4668
-4669                let starting_space = self.highest_space;
-4670                self.process_early_payload(now, path_id, packet, qlog)?;
-4671
-4672                if self.side.is_server()
-4673                    && starting_space == SpaceKind::Initial
-4674                    && self.highest_space != SpaceKind::Initial
-4675                {
-4676                    let params = self
-4677                        .crypto_state
-4678                        .session
-4679                        .transport_parameters()?
-4680                        .ok_or_else(|| {
-4681                            TransportError::new(
-4682                                TransportErrorCode::crypto(0x6d),
-4683                                "transport parameters missing".to_owned(),
-4684                            )
-4685                        })?;
-4686                    self.handle_peer_params(params, local_cid, remote_cid, now)?;
-4687                    self.issue_first_cids(now);
-4688                    self.init_0rtt(now);
-4689                }
-4690                Ok(())
-4691            }
-4692            Header::Long {
-4693                ty: LongType::ZeroRtt,
-4694                ..
-4695            } => {
-4696                self.process_payload(now, network_path, path_id, number.unwrap(), packet, qlog)?;
+4601                    if self.has_0rtt() {
+4602                        if !self.crypto_state.session.early_data_accepted().unwrap() {
+4603                            debug_assert!(self.side.is_client());
+4604                            debug!("0-RTT rejected");
+4605                            self.crypto_state.accepted_0rtt = false;
+4606                            self.streams.zero_rtt_rejected();
+4607
+4608                            // Discard already-queued frames
+4609                            self.spaces[SpaceId::Data].pending = Retransmits::default();
+4610
+4611                            // Discard 0-RTT packets
+4612                            let sent_packets = mem::take(
+4613                                &mut self.spaces[SpaceId::Data].for_path(path_id).sent_packets,
+4614                            );
+4615                            for (_, packet) in sent_packets.into_iter() {
+4616                                self.paths
+4617                                    .get_mut(&path_id)
+4618                                    .unwrap()
+4619                                    .remove_in_flight(&packet);
+4620                            }
+4621                        } else {
+4622                            self.crypto_state.accepted_0rtt = true;
+4623                            params.validate_resumption_from(&self.peer_params)?;
+4624                        }
+4625                    }
+4626                    if let Some(token) = params.stateless_reset_token {
+4627                        let remote = self.path_data(path_id).network_path.remote;
+4628                        debug_assert!(!self.state.is_drained()); // requirement for endpoint events, checked above
+4629                        self.endpoint_events
+4630                            .push_back(EndpointEventInner::ResetToken(path_id, remote, token));
+4631                    }
+4632                    self.handle_peer_params(params, local_cid, remote_cid, now)?;
+4633                    self.issue_first_cids(now);
+4634                } else {
+4635                    // Server-only
+4636                    self.spaces[SpaceId::Data].pending.handshake_done = true;
+4637                    self.discard_space(now, SpaceKind::Handshake);
+4638                    self.events.push_back(Event::HandshakeConfirmed);
+4639                    trace!("handshake confirmed");
+4640                }
+4641
+4642                self.events.push_back(Event::Connected);
+4643                self.state.move_to_established();
+4644                trace!("established");
+4645
+4646                // Multipath can only be enabled after the state has reached Established.
+4647                // So this can not happen any earlier.
+4648                self.issue_first_path_cids(now);
+4649                Ok(())
+4650            }
+4651            Header::Initial(InitialHeader {
+4652                src_cid: remote_cid,
+4653                dst_cid: local_cid,
+4654                ..
+4655            }) => {
+4656                debug_assert_eq!(path_id, PathId::ZERO);
+4657                if !state.remote_cid_set {
+4658                    trace!("switching remote CID to {}", remote_cid);
+4659                    let mut state = state.clone();
+4660                    self.remote_cids
+4661                        .get_mut(&path_id)
+4662                        .expect("PathId::ZERO not yet abandoned")
+4663                        .update_initial_cid(remote_cid);
+4664                    self.remote_handshake_cid = remote_cid;
+4665                    self.original_remote_cid = remote_cid;
+4666                    state.remote_cid_set = true;
+4667                    self.state.move_to_handshake(state);
+4668                } else if remote_cid != self.remote_handshake_cid {
+4669                    debug!(
+4670                        "discarding packet with mismatched remote CID: {} != {}",
+4671                        self.remote_handshake_cid, remote_cid
+4672                    );
+4673                    return Ok(());
+4674                }
+4675
+4676                let starting_space = self.highest_space;
+4677                self.process_early_payload(now, path_id, packet, qlog)?;
+4678
+4679                if self.side.is_server()
+4680                    && starting_space == SpaceKind::Initial
+4681                    && self.highest_space != SpaceKind::Initial
+4682                {
+4683                    let params = self
+4684                        .crypto_state
+4685                        .session
+4686                        .transport_parameters()?
+4687                        .ok_or_else(|| {
+4688                            TransportError::new(
+4689                                TransportErrorCode::crypto(0x6d),
+4690                                "transport parameters missing".to_owned(),
+4691                            )
+4692                        })?;
+4693                    self.handle_peer_params(params, local_cid, remote_cid, now)?;
+4694                    self.issue_first_cids(now);
+4695                    self.init_0rtt(now);
+4696                }
 4697                Ok(())
 4698            }
-4699            Header::VersionNegotiate { .. } => {
-4700                if self.total_authed_packets > 1 {
-4701                    return Ok(());
-4702                }
-4703                let supported = packet
-4704                    .payload
-4705                    .chunks(4)
-4706                    .any(|x| match <[u8; 4]>::try_from(x) {
-4707                        Ok(version) => self.version == u32::from_be_bytes(version),
-4708                        Err(_) => false,
-4709                    });
-4710                if supported {
-4711                    return Ok(());
-4712                }
-4713                debug!("remote doesn't support our version");
-4714                Err(ConnectionError::VersionMismatch)
-4715            }
-4716            Header::Short { .. } => unreachable!(
-4717                "short packets received during handshake are discarded in handle_packet"
-4718            ),
-4719        }
-4720    }
-4721
-4722    /// Process an Initial or Handshake packet payload
-4723    fn process_early_payload(
-4724        &mut self,
-4725        now: Instant,
-4726        path_id: PathId,
-4727        packet: Packet,
-4728        #[allow(unused)] qlog: &mut QlogRecvPacket,
-4729    ) -> Result<(), TransportError> {
-4730        debug_assert_ne!(packet.header.space(), SpaceKind::Data);
-4731        debug_assert_eq!(path_id, PathId::ZERO);
-4732        let payload_len = packet.payload.len();
-4733        let mut ack_eliciting = false;
-4734        for result in frame::Iter::new(packet.payload.freeze())? {
-4735            let frame = result?;
-4736            qlog.frame(&frame);
-4737            let span = match frame {
-4738                Frame::Padding => continue,
-4739                _ => Some(trace_span!("frame", ty = %frame.ty(), path = tracing::field::Empty)),
-4740            };
-4741
-4742            self.path_stats
-4743                .for_path(path_id)
-4744                .frame_rx
-4745                .record(frame.ty());
-4746
-4747            let _guard = span.as_ref().map(|x| x.enter());
-4748            ack_eliciting |= frame.is_ack_eliciting();
-4749
-4750            // Process frames
-4751            if frame.is_1rtt() && packet.header.space() != SpaceKind::Data {
-4752                return Err(TransportError::PROTOCOL_VIOLATION(
-4753                    "illegal frame type in handshake",
-4754                ));
-4755            }
+4699            Header::Long {
+4700                ty: LongType::ZeroRtt,
+4701                ..
+4702            } => {
+4703                self.process_payload(now, network_path, path_id, number.unwrap(), packet, qlog)?;
+4704                Ok(())
+4705            }
+4706            Header::VersionNegotiate { .. } => {
+4707                if self.total_authed_packets > 1 {
+4708                    return Ok(());
+4709                }
+4710                let supported = packet
+4711                    .payload
+4712                    .chunks(4)
+4713                    .any(|x| match <[u8; 4]>::try_from(x) {
+4714                        Ok(version) => self.version == u32::from_be_bytes(version),
+4715                        Err(_) => false,
+4716                    });
+4717                if supported {
+4718                    return Ok(());
+4719                }
+4720                debug!("remote doesn't support our version");
+4721                Err(ConnectionError::VersionMismatch)
+4722            }
+4723            Header::Short { .. } => unreachable!(
+4724                "short packets received during handshake are discarded in handle_packet"
+4725            ),
+4726        }
+4727    }
+4728
+4729    /// Process an Initial or Handshake packet payload
+4730    fn process_early_payload(
+4731        &mut self,
+4732        now: Instant,
+4733        path_id: PathId,
+4734        packet: Packet,
+4735        #[allow(unused)] qlog: &mut QlogRecvPacket,
+4736    ) -> Result<(), TransportError> {
+4737        debug_assert_ne!(packet.header.space(), SpaceKind::Data);
+4738        debug_assert_eq!(path_id, PathId::ZERO);
+4739        let payload_len = packet.payload.len();
+4740        let mut ack_eliciting = false;
+4741        for result in frame::Iter::new(packet.payload.freeze())? {
+4742            let frame = result?;
+4743            qlog.frame(&frame);
+4744            let span = match frame {
+4745                Frame::Padding => continue,
+4746                _ => Some(trace_span!("frame", ty = %frame.ty(), path = tracing::field::Empty)),
+4747            };
+4748
+4749            self.path_stats
+4750                .for_path(path_id)
+4751                .frame_rx
+4752                .record(frame.ty());
+4753
+4754            let _guard = span.as_ref().map(|x| x.enter());
+4755            ack_eliciting |= frame.is_ack_eliciting();
 4756
-4757            match frame {
-4758                Frame::Padding | Frame::Ping => {}
-4759                Frame::Crypto(frame) => {
-4760                    self.read_crypto(packet.header.space().into(), &frame, payload_len)?;
-4761                }
-4762                Frame::Ack(ack) => {
-4763                    self.on_ack_received(now, packet.header.space().into(), ack)?;
-4764                }
-4765                Frame::PathAck(ack) => {
-4766                    span.as_ref()
-4767                        .map(|span| span.record("path", tracing::field::display(&ack.path_id)));
-4768                    self.on_path_ack_received(now, packet.header.space().into(), ack)?;
-4769                }
-4770                Frame::Close(reason) => {
-4771                    self.state.move_to_draining(Some(reason.into()));
-4772                    return Ok(());
-4773                }
-4774                _ => {
-4775                    let mut err =
-4776                        TransportError::PROTOCOL_VIOLATION("illegal frame type in handshake");
-4777                    err.frame = frame::MaybeFrame::Known(frame.ty());
-4778                    return Err(err);
-4779                }
-4780            }
-4781        }
-4782
-4783        if ack_eliciting {
-4784            // In the initial and handshake spaces, ACKs must be sent immediately
-4785            self.spaces[packet.header.space()]
-4786                .for_path(path_id)
-4787                .pending_acks
-4788                .set_immediate_ack_required();
-4789        }
-4790
-4791        self.write_crypto();
-4792        Ok(())
-4793    }
-4794
-4795    /// Processes the decrypted packet payload, always in the data space.
-4796    fn process_payload(
-4797        &mut self,
-4798        now: Instant,
-4799        network_path: FourTuple,
-4800        path_id: PathId,
-4801        number: u64,
-4802        packet: Packet,
-4803        #[allow(unused)] qlog: &mut QlogRecvPacket,
-4804    ) -> Result<(), TransportError> {
-4805        let is_multipath_negotiated = self.is_multipath_negotiated();
-4806        let payload = packet.payload.freeze();
-4807        let mut is_probing_packet = true;
-4808        let mut close = None;
-4809        let payload_len = payload.len();
-4810        let mut ack_eliciting = false;
-4811        // if this packet triggers a path migration and includes a observed address frame, it's
-4812        // stored here
-4813        let mut migration_observed_addr = None;
-4814        for result in frame::Iter::new(payload)? {
-4815            let frame = result?;
-4816            qlog.frame(&frame);
-4817            let span = match frame {
-4818                Frame::Padding => continue,
-4819                _ => trace_span!("frame", ty = %frame.ty(), path = tracing::field::Empty),
-4820            };
-4821
-4822            self.path_stats
-4823                .for_path(path_id)
-4824                .frame_rx
-4825                .record(frame.ty());
-4826            // Crypto, Stream and Datagram frames are special cased in order no pollute
-4827            // the log with payload data
-4828            match &frame {
-4829                Frame::Crypto(f) => {
-4830                    trace!(offset = f.offset, len = f.data.len(), "got frame CRYPTO");
-4831                }
-4832                Frame::Stream(f) => {
-4833                    trace!(id = %f.id, offset = f.offset, len = f.data.len(), fin = f.fin, "got frame STREAM");
-4834                }
-4835                Frame::Datagram(f) => {
-4836                    trace!(len = f.data.len(), "got frame DATAGRAM");
-4837                }
-4838                f => {
-4839                    trace!("got frame {f}");
-4840                }
-4841            }
-4842
-4843            let _guard = span.enter();
-4844            if packet.header.is_0rtt() {
-4845                match frame {
-4846                    Frame::Crypto(_) | Frame::Close(Close::Application(_)) => {
-4847                        return Err(TransportError::PROTOCOL_VIOLATION(
-4848                            "illegal frame type in 0-RTT",
-4849                        ));
-4850                    }
-4851                    _ => {
-4852                        if frame.is_1rtt() {
-4853                            return Err(TransportError::PROTOCOL_VIOLATION(
-4854                                "illegal frame type in 0-RTT",
-4855                            ));
-4856                        }
+4757            // Process frames
+4758            if frame.is_1rtt() && packet.header.space() != SpaceKind::Data {
+4759                return Err(TransportError::PROTOCOL_VIOLATION(
+4760                    "illegal frame type in handshake",
+4761                ));
+4762            }
+4763
+4764            match frame {
+4765                Frame::Padding | Frame::Ping => {}
+4766                Frame::Crypto(frame) => {
+4767                    self.read_crypto(packet.header.space().into(), &frame, payload_len)?;
+4768                }
+4769                Frame::Ack(ack) => {
+4770                    self.on_ack_received(now, packet.header.space().into(), ack)?;
+4771                }
+4772                Frame::PathAck(ack) => {
+4773                    span.as_ref()
+4774                        .map(|span| span.record("path", tracing::field::display(&ack.path_id)));
+4775                    self.on_path_ack_received(now, packet.header.space().into(), ack)?;
+4776                }
+4777                Frame::Close(reason) => {
+4778                    self.state.move_to_draining(Some(reason.into()));
+4779                    return Ok(());
+4780                }
+4781                _ => {
+4782                    let mut err =
+4783                        TransportError::PROTOCOL_VIOLATION("illegal frame type in handshake");
+4784                    err.frame = frame::MaybeFrame::Known(frame.ty());
+4785                    return Err(err);
+4786                }
+4787            }
+4788        }
+4789
+4790        if ack_eliciting {
+4791            // In the initial and handshake spaces, ACKs must be sent immediately
+4792            self.spaces[packet.header.space()]
+4793                .for_path(path_id)
+4794                .pending_acks
+4795                .set_immediate_ack_required();
+4796        }
+4797
+4798        self.write_crypto();
+4799        Ok(())
+4800    }
+4801
+4802    /// Processes the decrypted packet payload, always in the data space.
+4803    fn process_payload(
+4804        &mut self,
+4805        now: Instant,
+4806        network_path: FourTuple,
+4807        path_id: PathId,
+4808        number: u64,
+4809        packet: Packet,
+4810        #[allow(unused)] qlog: &mut QlogRecvPacket,
+4811    ) -> Result<(), TransportError> {
+4812        let is_multipath_negotiated = self.is_multipath_negotiated();
+4813        let payload = packet.payload.freeze();
+4814        let mut is_probing_packet = true;
+4815        let mut close = None;
+4816        let payload_len = payload.len();
+4817        let mut ack_eliciting = false;
+4818        // if this packet triggers a path migration and includes a observed address frame, it's
+4819        // stored here
+4820        let mut migration_observed_addr = None;
+4821        for result in frame::Iter::new(payload)? {
+4822            let frame = result?;
+4823            qlog.frame(&frame);
+4824            let span = match frame {
+4825                Frame::Padding => continue,
+4826                _ => trace_span!("frame", ty = %frame.ty(), path = tracing::field::Empty),
+4827            };
+4828
+4829            self.path_stats
+4830                .for_path(path_id)
+4831                .frame_rx
+4832                .record(frame.ty());
+4833            // Crypto, Stream and Datagram frames are special cased in order no pollute
+4834            // the log with payload data
+4835            match &frame {
+4836                Frame::Crypto(f) => {
+4837                    trace!(offset = f.offset, len = f.data.len(), "got frame CRYPTO");
+4838                }
+4839                Frame::Stream(f) => {
+4840                    trace!(id = %f.id, offset = f.offset, len = f.data.len(), fin = f.fin, "got frame STREAM");
+4841                }
+4842                Frame::Datagram(f) => {
+4843                    trace!(len = f.data.len(), "got frame DATAGRAM");
+4844                }
+4845                f => {
+4846                    trace!("got frame {f}");
+4847                }
+4848            }
+4849
+4850            let _guard = span.enter();
+4851            if packet.header.is_0rtt() {
+4852                match frame {
+4853                    Frame::Crypto(_) | Frame::Close(Close::Application(_)) => {
+4854                        return Err(TransportError::PROTOCOL_VIOLATION(
+4855                            "illegal frame type in 0-RTT",
+4856                        ));
 4857                    }
-4858                }
-4859            }
-4860            ack_eliciting |= frame.is_ack_eliciting();
-4861
-4862            // Check whether this could be a probing packet
-4863            match frame {
-4864                Frame::Padding
-4865                | Frame::PathChallenge(_)
-4866                | Frame::PathResponse(_)
-4867                | Frame::NewConnectionId(_)
-4868                | Frame::ObservedAddr(_) => {}
-4869                _ => {
-4870                    is_probing_packet = false;
-4871                }
-4872            }
-4873
-4874            match frame {
-4875                Frame::Crypto(frame) => {
-4876                    self.read_crypto(SpaceId::Data, &frame, payload_len)?;
-4877                }
-4878                Frame::Stream(frame) => {
-4879                    if self.streams.received(frame, payload_len)?.should_transmit() {
-4880                        self.spaces[SpaceId::Data].pending.max_data = true;
-4881                    }
-4882                }
-4883                Frame::Ack(ack) => {
-4884                    self.on_ack_received(now, SpaceId::Data, ack)?;
-4885                }
-4886                Frame::PathAck(ack) => {
-4887                    if !self.is_multipath_negotiated() {
-4888                        return Err(TransportError::PROTOCOL_VIOLATION(
-4889                            "received PATH_ACK frame when multipath was not negotiated",
-4890                        ));
-4891                    }
-4892                    span.record("path", tracing::field::display(&ack.path_id));
-4893                    self.on_path_ack_received(now, SpaceId::Data, ack)?;
-4894                }
-4895                Frame::Padding | Frame::Ping => {}
-4896                Frame::Close(reason) => {
-4897                    close = Some(reason);
-4898                }
-4899                Frame::PathChallenge(challenge) => {
-4900                    let path = &mut self
-4901                        .path_mut(path_id)
-4902                        .expect("payload is processed only after the path becomes known");
-4903                    path.path_responses.push(number, challenge.0, network_path);
-4904                    // If we were passively migrated (e.g. NAT rebinding), our local_ip will
-4905                    // not match. Once we processed a non-probing packet the local_ip will
-4906                    // finally be updated.
-4907                    if network_path.remote == path.network_path.remote {
-4908                        // PATH_CHALLENGE on active path, possible off-path packet
-4909                        // forwarding attack. Send a non-probing packet to recover the
-4910                        // active path. See
-4911                        // https://www.rfc-editor.org/rfc/rfc9000.html#section-9.3.3-3. In
-4912                        // rare cases NAT probes might also appear on-path and would also
-4913                        // get a non-probing packet as response. There is little harm in
-4914                        // this.
-4915                        match self.peer_supports_ack_frequency() {
-4916                            true => self.immediate_ack(path_id),
-4917                            false => {
-4918                                self.ping_path(path_id).ok();
-4919                            }
-4920                        }
-4921                    }
-4922                }
-4923                Frame::PathResponse(response) => {
-4924                    // First try to see if this is a NAT probe response.
-4925                    if let Ok(nat_state) = self.n0_nat_traversal.server_side_mut()
-4926                        && nat_state.handle_path_response(network_path, response.0)
-4927                    {
-4928                        trace!(
-4929                            src = ?network_path,
-4930                            challenge = response.0,
-4931                            "Received valid NAT traversal probe response"
-4932                        );
-4933                        // Server-side: nothing else to do.
-4934                    } else {
-4935                        // Try to see if this is a response to an on-path PATH_CHALLENGE.
-4936
-4937                        let path = self
-4938                            .paths
-4939                            .get_mut(&path_id)
-4940                            .expect("payload is processed only after the path becomes known");
-4941
-4942                        use PathTimer::*;
-4943                        use paths::OnPathResponseReceived::*;
-4944                        match path
-4945                            .data
-4946                            .on_path_response_received(now, response.0, network_path)
-4947                        {
-4948                            OnPath { was_open } => {
-4949                                let qlog = self.qlog.with_time(now);
-4950
-4951                                self.timers.stop(
-4952                                    Timer::PerPath(path_id, PathValidationFailed),
-4953                                    qlog.clone(),
-4954                                );
-4955                                self.timers.stop(
-4956                                    Timer::PerPath(path_id, AbandonFromValidation),
-4957                                    qlog.clone(),
-4958                                );
-4959
-4960                                let next_challenge = path
-4961                                    .data
-4962                                    .earliest_on_path_expiring_challenge()
-4963                                    .map(|time| time + self.ack_frequency.max_ack_delay_for_pto());
-4964                                self.timers.set_or_stop(
-4965                                    Timer::PerPath(path_id, PathChallengeLost),
-4966                                    next_challenge,
-4967                                    qlog,
-4968                                );
-4969
-4970                                if !was_open {
-4971                                    if is_multipath_negotiated {
-4972                                        self.events.push_back(Event::Path(PathEvent::Opened {
-4973                                            id: path_id,
-4974                                        }));
-4975                                    }
-4976                                    if let Some(observed) =
-4977                                        path.data.last_observed_addr_report.as_ref()
-4978                                    {
-4979                                        self.events.push_back(Event::Path(
-4980                                            PathEvent::ObservedAddr {
-4981                                                id: path_id,
-4982                                                addr: observed.socket_addr(),
-4983                                            },
-4984                                        ));
-4985                                    }
-4986                                }
-4987                                if let Some((_, ref mut prev)) = path.prev {
-4988                                    // If an on-path response was received while there is a
-4989                                    // previous path from a migration, then the new path is
-4990                                    // validated and we can stop sending challenges that try to
-4991                                    // re-validate the previous path.
-4992                                    prev.reset_on_path_challenges();
-4993                                }
-4994                            }
-4995                            Ignored {
-4996                                sent_on,
-4997                                current_path,
-4998                            } => {
-4999                                debug!(%sent_on, %current_path, %response, "ignoring valid PATH_RESPONSE")
-5000                            }
-5001                            Unknown => debug!(%response, "ignoring invalid PATH_RESPONSE"),
-5002                        }
-5003                    }
-5004                }
-5005                Frame::MaxData(frame::MaxData(bytes)) => {
-5006                    self.streams.received_max_data(bytes);
+4858                    _ => {
+4859                        if frame.is_1rtt() {
+4860                            return Err(TransportError::PROTOCOL_VIOLATION(
+4861                                "illegal frame type in 0-RTT",
+4862                            ));
+4863                        }
+4864                    }
+4865                }
+4866            }
+4867            ack_eliciting |= frame.is_ack_eliciting();
+4868
+4869            // Check whether this could be a probing packet
+4870            match frame {
+4871                Frame::Padding
+4872                | Frame::PathChallenge(_)
+4873                | Frame::PathResponse(_)
+4874                | Frame::NewConnectionId(_)
+4875                | Frame::ObservedAddr(_) => {}
+4876                _ => {
+4877                    is_probing_packet = false;
+4878                }
+4879            }
+4880
+4881            match frame {
+4882                Frame::Crypto(frame) => {
+4883                    self.read_crypto(SpaceId::Data, &frame, payload_len)?;
+4884                }
+4885                Frame::Stream(frame) => {
+4886                    if self.streams.received(frame, payload_len)?.should_transmit() {
+4887                        self.spaces[SpaceId::Data].pending.max_data = true;
+4888                    }
+4889                }
+4890                Frame::Ack(ack) => {
+4891                    self.on_ack_received(now, SpaceId::Data, ack)?;
+4892                }
+4893                Frame::PathAck(ack) => {
+4894                    if !self.is_multipath_negotiated() {
+4895                        return Err(TransportError::PROTOCOL_VIOLATION(
+4896                            "received PATH_ACK frame when multipath was not negotiated",
+4897                        ));
+4898                    }
+4899                    span.record("path", tracing::field::display(&ack.path_id));
+4900                    self.on_path_ack_received(now, SpaceId::Data, ack)?;
+4901                }
+4902                Frame::Padding | Frame::Ping => {}
+4903                Frame::Close(reason) => {
+4904                    close = Some(reason);
+4905                }
+4906                Frame::PathChallenge(challenge) => {
+4907                    let path = &mut self
+4908                        .path_mut(path_id)
+4909                        .expect("payload is processed only after the path becomes known");
+4910                    path.path_responses.push(number, challenge.0, network_path);
+4911                    // If we were passively migrated (e.g. NAT rebinding), our local_ip will
+4912                    // not match. Once we processed a non-probing packet the local_ip will
+4913                    // finally be updated.
+4914                    if network_path.remote == path.network_path.remote {
+4915                        // PATH_CHALLENGE on active path, possible off-path packet
+4916                        // forwarding attack. Send a non-probing packet to recover the
+4917                        // active path. See
+4918                        // https://www.rfc-editor.org/rfc/rfc9000.html#section-9.3.3-3. In
+4919                        // rare cases NAT probes might also appear on-path and would also
+4920                        // get a non-probing packet as response. There is little harm in
+4921                        // this.
+4922                        match self.peer_supports_ack_frequency() {
+4923                            true => self.immediate_ack(path_id),
+4924                            false => {
+4925                                self.ping_path(path_id).ok();
+4926                            }
+4927                        }
+4928                    }
+4929                }
+4930                Frame::PathResponse(response) => {
+4931                    // First try to see if this is a NAT probe response.
+4932                    if self
+4933                        .n0_nat_traversal
+4934                        .handle_path_response(network_path, response.0)
+4935                    {
+4936                        self.open_nat_traversed_paths(now);
+4937                    } else {
+4938                        // Try to see if this is a response to an on-path PATH_CHALLENGE.
+4939
+4940                        let path = self
+4941                            .paths
+4942                            .get_mut(&path_id)
+4943                            .expect("payload is processed only after the path becomes known");
+4944
+4945                        use PathTimer::*;
+4946                        use paths::OnPathResponseReceived::*;
+4947                        match path
+4948                            .data
+4949                            .on_path_response_received(now, response.0, network_path)
+4950                        {
+4951                            OnPath { was_open } => {
+4952                                let qlog = self.qlog.with_time(now);
+4953
+4954                                self.timers.stop(
+4955                                    Timer::PerPath(path_id, PathValidationFailed),
+4956                                    qlog.clone(),
+4957                                );
+4958                                self.timers.stop(
+4959                                    Timer::PerPath(path_id, AbandonFromValidation),
+4960                                    qlog.clone(),
+4961                                );
+4962
+4963                                let next_challenge = path
+4964                                    .data
+4965                                    .earliest_on_path_expiring_challenge()
+4966                                    .map(|time| time + self.ack_frequency.max_ack_delay_for_pto());
+4967                                self.timers.set_or_stop(
+4968                                    Timer::PerPath(path_id, PathChallengeLost),
+4969                                    next_challenge,
+4970                                    qlog,
+4971                                );
+4972
+4973                                if !was_open {
+4974                                    if is_multipath_negotiated {
+4975                                        self.events.push_back(Event::Path(PathEvent::Opened {
+4976                                            id: path_id,
+4977                                        }));
+4978                                    }
+4979                                    if let Some(observed) =
+4980                                        path.data.last_observed_addr_report.as_ref()
+4981                                    {
+4982                                        self.events.push_back(Event::Path(
+4983                                            PathEvent::ObservedAddr {
+4984                                                id: path_id,
+4985                                                addr: observed.socket_addr(),
+4986                                            },
+4987                                        ));
+4988                                    }
+4989                                }
+4990                                if let Some((_, ref mut prev)) = path.prev {
+4991                                    // If an on-path response was received while there is a
+4992                                    // previous path from a migration, then the new path is
+4993                                    // validated and we can stop sending challenges that try to
+4994                                    // re-validate the previous path.
+4995                                    prev.reset_on_path_challenges();
+4996                                }
+4997                            }
+4998                            Ignored {
+4999                                sent_on,
+5000                                current_path,
+5001                            } => {
+5002                                debug!(%sent_on, %current_path, %response, "ignoring valid PATH_RESPONSE")
+5003                            }
+5004                            Unknown => debug!(%response, "ignoring invalid PATH_RESPONSE"),
+5005                        }
+5006                    }
 5007                }
-5008                Frame::MaxStreamData(frame::MaxStreamData { id, offset }) => {
-5009                    self.streams.received_max_stream_data(id, offset)?;
+5008                Frame::MaxData(frame::MaxData(bytes)) => {
+5009                    self.streams.received_max_data(bytes);
 5010                }
-5011                Frame::MaxStreams(frame::MaxStreams { dir, count }) => {
-5012                    self.streams.received_max_streams(dir, count)?;
+5011                Frame::MaxStreamData(frame::MaxStreamData { id, offset }) => {
+5012                    self.streams.received_max_stream_data(id, offset)?;
 5013                }
-5014                Frame::ResetStream(frame) => {
-5015                    if self.streams.received_reset(frame)?.should_transmit() {
-5016                        self.spaces[SpaceId::Data].pending.max_data = true;
-5017                    }
-5018                }
-5019                Frame::DataBlocked(DataBlocked(offset)) => {
-5020                    debug!(offset, "peer claims to be blocked at connection level");
+5014                Frame::MaxStreams(frame::MaxStreams { dir, count }) => {
+5015                    self.streams.received_max_streams(dir, count)?;
+5016                }
+5017                Frame::ResetStream(frame) => {
+5018                    if self.streams.received_reset(frame)?.should_transmit() {
+5019                        self.spaces[SpaceId::Data].pending.max_data = true;
+5020                    }
 5021                }
-5022                Frame::StreamDataBlocked(StreamDataBlocked { id, offset }) => {
-5023                    if id.initiator() == self.side.side() && id.dir() == Dir::Uni {
-5024                        debug!("got STREAM_DATA_BLOCKED on send-only {}", id);
-5025                        return Err(TransportError::STREAM_STATE_ERROR(
-5026                            "STREAM_DATA_BLOCKED on send-only stream",
-5027                        ));
-5028                    }
-5029                    debug!(
-5030                        stream = %id,
-5031                        offset, "peer claims to be blocked at stream level"
-5032                    );
-5033                }
-5034                Frame::StreamsBlocked(StreamsBlocked { dir, limit }) => {
-5035                    if limit > MAX_STREAM_COUNT {
-5036                        return Err(TransportError::FRAME_ENCODING_ERROR(
-5037                            "unrepresentable stream limit",
-5038                        ));
-5039                    }
-5040                    debug!(
-5041                        "peer claims to be blocked opening more than {} {} streams",
-5042                        limit, dir
-5043                    );
-5044                }
-5045                Frame::StopSending(frame::StopSending { id, error_code }) => {
-5046                    if id.initiator() != self.side.side() {
-5047                        if id.dir() == Dir::Uni {
-5048                            debug!("got STOP_SENDING on recv-only {}", id);
-5049                            return Err(TransportError::STREAM_STATE_ERROR(
-5050                                "STOP_SENDING on recv-only stream",
-5051                            ));
-5052                        }
-5053                    } else if self.streams.is_local_unopened(id) {
-5054                        return Err(TransportError::STREAM_STATE_ERROR(
-5055                            "STOP_SENDING on unopened stream",
-5056                        ));
-5057                    }
-5058                    self.streams.received_stop_sending(id, error_code);
-5059                }
-5060                Frame::RetireConnectionId(frame::RetireConnectionId { path_id, sequence }) => {
-5061                    if let Some(ref path_id) = path_id {
-5062                        span.record("path", tracing::field::display(&path_id));
-5063                    }
-5064                    let path_id = path_id.unwrap_or_default();
-5065                    match self.local_cid_state.get_mut(&path_id) {
-5066                        None => error!(?path_id, "RETIRE_CONNECTION_ID for unknown path"),
-5067                        Some(cid_state) => {
-5068                            let allow_more_cids = cid_state
-5069                                .on_cid_retirement(sequence, self.peer_params.issue_cids_limit())?;
-5070
-5071                            // If the path has closed, we do not issue more CIDs for this path
-5072                            // For details see  https://www.ietf.org/archive/id/draft-ietf-quic-multipath-17.html#section-3.2.2
-5073                            // > an endpoint SHOULD provide new connection IDs for that path, if still open, using PATH_NEW_CONNECTION_ID frames.
-5074                            let has_path = !self.abandoned_paths.contains(&path_id);
-5075                            let allow_more_cids = allow_more_cids && has_path;
-5076
-5077                            debug_assert!(!self.state.is_drained()); // required for adding endpoint events, process_payload is never called for drained connections
-5078                            self.endpoint_events
-5079                                .push_back(EndpointEventInner::RetireConnectionId(
-5080                                    now,
-5081                                    path_id,
-5082                                    sequence,
-5083                                    allow_more_cids,
-5084                                ));
-5085                        }
-5086                    }
-5087                }
-5088                Frame::NewConnectionId(frame) => {
-5089                    let path_id = if let Some(path_id) = frame.path_id {
-5090                        if !self.is_multipath_negotiated() {
-5091                            return Err(TransportError::PROTOCOL_VIOLATION(
-5092                                "received PATH_NEW_CONNECTION_ID frame when multipath was not negotiated",
-5093                            ));
-5094                        }
-5095                        if path_id > self.local_max_path_id {
-5096                            return Err(TransportError::PROTOCOL_VIOLATION(
-5097                                "PATH_NEW_CONNECTION_ID contains path_id exceeding current max",
-5098                            ));
-5099                        }
-5100                        path_id
-5101                    } else {
-5102                        PathId::ZERO
-5103                    };
-5104
-5105                    if let Some(ref path_id) = frame.path_id {
-5106                        span.record("path", tracing::field::display(&path_id));
-5107                    }
-5108
-5109                    if self.abandoned_paths.contains(&path_id) {
-5110                        trace!("ignoring issued CID for abandoned path");
-5111                        continue;
-5112                    }
-5113                    let remote_cids = self
-5114                        .remote_cids
-5115                        .entry(path_id)
-5116                        .or_insert_with(|| CidQueue::new(frame.id));
-5117                    if remote_cids.active().is_empty() {
-5118                        return Err(TransportError::PROTOCOL_VIOLATION(
-5119                            "NEW_CONNECTION_ID when CIDs aren't in use",
-5120                        ));
-5121                    }
-5122                    if frame.retire_prior_to > frame.sequence {
-5123                        return Err(TransportError::PROTOCOL_VIOLATION(
-5124                            "NEW_CONNECTION_ID retiring unissued CIDs",
-5125                        ));
-5126                    }
-5127
-5128                    use crate::cid_queue::InsertError;
-5129                    match remote_cids.insert(frame) {
-5130                        Ok(None) if self.path(path_id).is_none() => {
-5131                            // TODO(flub): Once the client does off-path NAT probes as well
-5132                            //    we should remove this.
-5133                            // If this gives us CIDs to open a new path and a nat traversal attempt
-5134                            // is underway we could try to probe a pending remote
-5135                            self.continue_nat_traversal_round(now);
-5136                        }
-5137                        Ok(None) => {}
-5138                        Ok(Some((retired, reset_token))) => {
-5139                            let pending_retired =
-5140                                &mut self.spaces[SpaceId::Data].pending.retire_cids;
-5141                            /// Ensure `pending_retired` cannot grow without bound. Limit is
-5142                            /// somewhat arbitrary but very permissive.
-5143                            const MAX_PENDING_RETIRED_CIDS: u64 = CidQueue::LEN as u64 * 10;
-5144                            // We don't bother counting in-flight frames because those are bounded
-5145                            // by congestion control.
-5146                            if (pending_retired.len() as u64)
-5147                                .saturating_add(retired.end.saturating_sub(retired.start))
-5148                                > MAX_PENDING_RETIRED_CIDS
-5149                            {
-5150                                return Err(TransportError::CONNECTION_ID_LIMIT_ERROR(
-5151                                    "queued too many retired CIDs",
-5152                                ));
-5153                            }
-5154                            pending_retired.extend(retired.map(|seq| (path_id, seq)));
-5155                            self.set_reset_token(path_id, network_path.remote, reset_token);
-5156                        }
-5157                        Err(InsertError::ExceedsLimit) => {
-5158                            return Err(TransportError::CONNECTION_ID_LIMIT_ERROR(""));
-5159                        }
-5160                        Err(InsertError::Retired) => {
-5161                            trace!("discarding already-retired");
-5162                            // RETIRE_CONNECTION_ID might not have been previously sent if e.g. a
-5163                            // range of connection IDs larger than the active connection ID limit
-5164                            // was retired all at once via retire_prior_to.
-5165                            self.spaces[SpaceId::Data]
-5166                                .pending
-5167                                .retire_cids
-5168                                .push((path_id, frame.sequence));
-5169                            continue;
-5170                        }
-5171                    };
-5172
-5173                    if self.side.is_server()
-5174                        && path_id == PathId::ZERO
-5175                        && self
-5176                            .remote_cids
-5177                            .get(&PathId::ZERO)
-5178                            .map(|cids| cids.active_seq() == 0)
-5179                            .unwrap_or_default()
-5180                    {
-5181                        // We're a server still using the initial remote CID for the client, so
-5182                        // let's switch immediately to enable clientside stateless resets.
-5183                        self.update_remote_cid(PathId::ZERO);
-5184                    }
-5185                }
-5186                Frame::NewToken(NewToken { token }) => {
-5187                    let ConnectionSide::Client {
-5188                        token_store,
-5189                        server_name,
-5190                        ..
-5191                    } = &self.side
-5192                    else {
-5193                        return Err(TransportError::PROTOCOL_VIOLATION("client sent NEW_TOKEN"));
-5194                    };
-5195                    if token.is_empty() {
-5196                        return Err(TransportError::FRAME_ENCODING_ERROR("empty token"));
-5197                    }
-5198                    trace!("got new token");
-5199                    token_store.insert(server_name, token);
-5200                }
-5201                Frame::Datagram(datagram) => {
-5202                    if self
-5203                        .datagrams
-5204                        .received(datagram, &self.config.datagram_receive_buffer_size)?
-5205                    {
-5206                        self.events.push_back(Event::DatagramReceived);
-5207                    }
-5208                }
-5209                Frame::AckFrequency(ack_frequency) => {
-5210                    // This frame can only be sent in the Data space
-5211
-5212                    if !self.ack_frequency.ack_frequency_received(&ack_frequency)? {
-5213                        // The AckFrequency frame is stale (we have already received a more
-5214                        // recent one)
-5215                        continue;
-5216                    }
-5217
-5218                    // Update the params for all of our paths
-5219                    for (path_id, space) in self.spaces[SpaceId::Data].number_spaces.iter_mut() {
-5220                        space.pending_acks.set_ack_frequency_params(&ack_frequency);
-5221
-5222                        // Our `max_ack_delay` has been updated, so we may need to adjust
-5223                        // its associated timeout.
-5224                        // Packets received on abandoned paths are always acknowledged immediately.
-5225                        if !self.abandoned_paths.contains(path_id)
-5226                            && let Some(timeout) = space
-5227                                .pending_acks
-5228                                .max_ack_delay_timeout(self.ack_frequency.max_ack_delay)
-5229                        {
-5230                            self.timers.set(
-5231                                Timer::PerPath(*path_id, PathTimer::MaxAckDelay),
-5232                                timeout,
-5233                                self.qlog.with_time(now),
-5234                            );
-5235                        }
-5236                    }
-5237                }
-5238                Frame::ImmediateAck => {
-5239                    // This frame can only be sent in the Data space
-5240                    for pns in self.spaces[SpaceId::Data].iter_paths_mut() {
-5241                        pns.pending_acks.set_immediate_ack_required();
-5242                    }
-5243                }
-5244                Frame::HandshakeDone => {
-5245                    if self.side.is_server() {
-5246                        return Err(TransportError::PROTOCOL_VIOLATION(
-5247                            "client sent HANDSHAKE_DONE",
-5248                        ));
-5249                    }
-5250                    if self.crypto_state.has_keys(EncryptionLevel::Handshake) {
-5251                        self.discard_space(now, SpaceKind::Handshake);
-5252                        self.events.push_back(Event::HandshakeConfirmed);
-5253                        trace!("handshake confirmed");
-5254                    }
-5255                }
-5256                Frame::ObservedAddr(observed) => {
-5257                    // check if params allows the peer to send report and this node to receive it
-5258                    trace!(seq_no = %observed.seq_no, ip = %observed.ip, port = observed.port);
-5259                    if !self
-5260                        .peer_params
-5261                        .address_discovery_role
-5262                        .should_report(&self.config.address_discovery_role)
-5263                    {
-5264                        return Err(TransportError::PROTOCOL_VIOLATION(
-5265                            "received OBSERVED_ADDRESS frame when not negotiated",
-5266                        ));
-5267                    }
-5268                    // must only be sent in data space
-5269                    if packet.header.space() != SpaceKind::Data {
-5270                        return Err(TransportError::PROTOCOL_VIOLATION(
-5271                            "OBSERVED_ADDRESS frame outside data space",
-5272                        ));
-5273                    }
-5274
-5275                    let path = self.path_data_mut(path_id);
-5276                    if network_path == path.network_path {
-5277                        if let Some(updated) = path.update_observed_addr_report(observed)
-5278                            && path.open_status == paths::OpenStatus::Informed
-5279                        {
-5280                            self.events.push_back(Event::Path(PathEvent::ObservedAddr {
-5281                                id: path_id,
-5282                                addr: updated,
-5283                            }));
-5284                            // otherwise the event is reported when the path is deemed open
-5285                        }
-5286                    } else {
-5287                        // include in migration
-5288                        migration_observed_addr = Some(observed)
-5289                    }
-5290                }
-5291                Frame::PathAbandon(frame::PathAbandon {
-5292                    path_id,
-5293                    error_code,
-5294                }) => {
-5295                    span.record("path", tracing::field::display(&path_id));
-5296                    match self.close_path_inner(
-5297                        now,
-5298                        path_id,
-5299                        PathAbandonReason::RemoteAbandoned {
-5300                            error_code: error_code.into(),
-5301                        },
-5302                    ) {
-5303                        Ok(()) => {
-5304                            trace!("peer abandoned path");
-5305                        }
-5306                        Err(ClosePathError::ClosedPath) => {
-5307                            trace!("peer abandoned already closed path");
-5308                        }
-5309                        Err(ClosePathError::MultipathNotNegotiated) => {
-5310                            return Err(TransportError::PROTOCOL_VIOLATION(
-5311                                "received PATH_ABANDON frame when multipath was not negotiated",
-5312                            ));
-5313                        }
-5314                        Err(ClosePathError::LastOpenPath) => {
-5315                            // Not reachable: close_path_inner allows remote abandons
-5316                            // for the last path. But handle gracefully just in case.
-5317                            error!(
-5318                                "peer abandoned last path but close_path_inner returned LastOpenPath"
-5319                            );
-5320                        }
-5321                    };
-5322
-5323                    // Start draining the path if it still exists and hasn't started draining yet.
-5324                    if let Some(path) = self.paths.get_mut(&path_id)
-5325                        && !mem::replace(&mut path.data.draining, true)
-5326                    {
-5327                        let ack_delay = self.ack_frequency.max_ack_delay_for_pto();
-5328                        let pto = path.data.rtt.pto_base() + ack_delay;
-5329                        self.timers.set(
-5330                            Timer::PerPath(path_id, PathTimer::PathDrained),
-5331                            now + 3 * pto,
-5332                            self.qlog.with_time(now),
-5333                        );
-5334
-5335                        self.set_max_path_id(now, self.local_max_path_id.saturating_add(1u8));
-5336                    }
-5337                }
-5338                Frame::PathStatusAvailable(info) => {
-5339                    span.record("path", tracing::field::display(&info.path_id));
-5340                    if self.is_multipath_negotiated() {
-5341                        self.on_path_status(
-5342                            info.path_id,
-5343                            PathStatus::Available,
-5344                            info.status_seq_no,
-5345                        );
-5346                    } else {
-5347                        return Err(TransportError::PROTOCOL_VIOLATION(
-5348                            "received PATH_STATUS_AVAILABLE frame when multipath was not negotiated",
-5349                        ));
-5350                    }
-5351                }
-5352                Frame::PathStatusBackup(info) => {
-5353                    span.record("path", tracing::field::display(&info.path_id));
-5354                    if self.is_multipath_negotiated() {
-5355                        self.on_path_status(info.path_id, PathStatus::Backup, info.status_seq_no);
-5356                    } else {
-5357                        return Err(TransportError::PROTOCOL_VIOLATION(
-5358                            "received PATH_STATUS_BACKUP frame when multipath was not negotiated",
-5359                        ));
-5360                    }
-5361                }
-5362                Frame::MaxPathId(frame::MaxPathId(path_id)) => {
-5363                    span.record("path", tracing::field::display(&path_id));
-5364                    if !self.is_multipath_negotiated() {
-5365                        return Err(TransportError::PROTOCOL_VIOLATION(
-5366                            "received MAX_PATH_ID frame when multipath was not negotiated",
-5367                        ));
-5368                    }
-5369                    // frames that do not increase the path id are ignored
-5370                    if path_id > self.remote_max_path_id {
-5371                        self.remote_max_path_id = path_id;
-5372                        self.issue_first_path_cids(now);
-5373                        // TODO(flub): Once the client sends off-path NAT probes this is no
-5374                        //    longer needed. But new paths that need to be opened may need
-5375                        //    to be notified.
-5376                        while let Some(true) = self.continue_nat_traversal_round(now) {}
-5377                    }
-5378                }
-5379                Frame::PathsBlocked(frame::PathsBlocked(max_path_id)) => {
-5380                    // Receipt of a value of Maximum Path Identifier or Path Identifier that is higher than the local maximum value MUST
-5381                    // be treated as a connection error of type PROTOCOL_VIOLATION.
-5382                    // Ref <https://www.ietf.org/archive/id/draft-ietf-quic-multipath-14.html#name-paths_blocked-and-path_cids>
-5383                    if self.is_multipath_negotiated() {
-5384                        if max_path_id > self.local_max_path_id {
-5385                            return Err(TransportError::PROTOCOL_VIOLATION(
-5386                                "PATHS_BLOCKED maximum path identifier was larger than local maximum",
-5387                            ));
-5388                        }
-5389                        debug!("received PATHS_BLOCKED({:?})", max_path_id);
-5390                        // TODO(@divma): ensure max concurrent paths
-5391                    } else {
-5392                        return Err(TransportError::PROTOCOL_VIOLATION(
-5393                            "received PATHS_BLOCKED frame when not multipath was not negotiated",
-5394                        ));
-5395                    }
-5396                }
-5397                Frame::PathCidsBlocked(frame::PathCidsBlocked { path_id, next_seq }) => {
-5398                    // Nothing to do.  This is recorded in the frame stats, but otherwise we
-5399                    // always issue all CIDs we're allowed to issue, so either this is an
-5400                    // impatient peer or a bug on our side.
-5401
-5402                    // Receipt of a value of Maximum Path Identifier or Path Identifier that is higher than the local maximum value MUST
-5403                    // be treated as a connection error of type PROTOCOL_VIOLATION.
-5404                    // Ref <https://www.ietf.org/archive/id/draft-ietf-quic-multipath-14.html#name-paths_blocked-and-path_cids>
-5405                    if self.is_multipath_negotiated() {
-5406                        if path_id > self.local_max_path_id {
-5407                            return Err(TransportError::PROTOCOL_VIOLATION(
-5408                                "PATH_CIDS_BLOCKED path identifier was larger than local maximum",
-5409                            ));
-5410                        }
-5411                        if next_seq.0
-5412                            > self
-5413                                .local_cid_state
-5414                                .get(&path_id)
-5415                                .map(|cid_state| cid_state.active_seq().1 + 1)
-5416                                .unwrap_or_default()
-5417                        {
-5418                            return Err(TransportError::PROTOCOL_VIOLATION(
-5419                                "PATH_CIDS_BLOCKED next sequence number larger than in local state",
-5420                            ));
-5421                        }
-5422                        debug!(%path_id, %next_seq, "received PATH_CIDS_BLOCKED");
-5423                    } else {
-5424                        return Err(TransportError::PROTOCOL_VIOLATION(
-5425                            "received PATH_CIDS_BLOCKED frame when not multipath was not negotiated",
-5426                        ));
-5427                    }
-5428                }
-5429                Frame::AddAddress(addr) => {
-5430                    let client_state = match self.n0_nat_traversal.client_side_mut() {
-5431                        Ok(state) => state,
-5432                        Err(err) => {
-5433                            return Err(TransportError::PROTOCOL_VIOLATION(format!(
-5434                                "Nat traversal(ADD_ADDRESS): {err}"
-5435                            )));
-5436                        }
-5437                    };
-5438
-5439                    if !client_state.check_remote_address(&addr) {
-5440                        // if the address is not valid we flag it, but update anyway
-5441                        warn!(?addr, "server sent illegal ADD_ADDRESS frame");
-5442                    }
-5443
-5444                    match client_state.add_remote_address(addr) {
-5445                        Ok(maybe_added) => {
-5446                            if let Some(added) = maybe_added {
-5447                                self.events.push_back(Event::NatTraversal(
-5448                                    n0_nat_traversal::Event::AddressAdded(added),
-5449                                ));
-5450                            }
-5451                        }
-5452                        Err(e) => {
-5453                            warn!(%e, "failed to add remote address")
-5454                        }
-5455                    }
-5456                }
-5457                Frame::RemoveAddress(addr) => {
-5458                    let client_state = match self.n0_nat_traversal.client_side_mut() {
-5459                        Ok(state) => state,
-5460                        Err(err) => {
-5461                            return Err(TransportError::PROTOCOL_VIOLATION(format!(
-5462                                "Nat traversal(REMOVE_ADDRESS): {err}"
-5463                            )));
-5464                        }
-5465                    };
-5466                    if let Some(removed_addr) = client_state.remove_remote_address(addr) {
-5467                        self.events.push_back(Event::NatTraversal(
-5468                            n0_nat_traversal::Event::AddressRemoved(removed_addr),
-5469                        ));
-5470                    }
-5471                }
-5472                Frame::ReachOut(reach_out) => {
-5473                    let ipv6 = self.is_ipv6();
-5474                    let server_state = match self.n0_nat_traversal.server_side_mut() {
-5475                        Ok(state) => state,
-5476                        Err(err) => {
-5477                            return Err(TransportError::PROTOCOL_VIOLATION(format!(
-5478                                "Nat traversal(REACH_OUT): {err}"
-5479                            )));
-5480                        }
-5481                    };
-5482
-5483                    let round_before = server_state.current_round();
-5484
-5485                    if let Err(err) = server_state.handle_reach_out(reach_out, ipv6) {
-5486                        return Err(TransportError::PROTOCOL_VIOLATION(format!(
-5487                            "Nat traversal(REACH_OUT): {err}"
-5488                        )));
-5489                    }
-5490
-5491                    if server_state.current_round() > round_before {
-5492                        // A new round was started, reset the NAT probe retry timer.
-5493                        let delay = RttEstimator::new(self.config.initial_rtt).pto_base() * 2 / 3;
-5494                        self.timers.set(
-5495                            Timer::Conn(ConnTimer::NatTraversalProbeRetry),
-5496                            now + delay,
-5497                            self.qlog.with_time(now),
-5498                        );
-5499                    }
-5500                }
-5501            }
-5502        }
-5503
-5504        let space = self.spaces[SpaceId::Data].for_path(path_id);
-5505        if space
-5506            .pending_acks
-5507            .packet_received(now, number, ack_eliciting, &space.dedup)
-5508        {
-5509            if self.abandoned_paths.contains(&path_id) {
-5510                // § 3.4.3 QUIC-MULTIPATH: promptly send ACKs for packets received from
-5511                // abandoned paths.
-5512                space.pending_acks.set_immediate_ack_required();
-5513            } else {
-5514                self.timers.set(
-5515                    Timer::PerPath(path_id, PathTimer::MaxAckDelay),
-5516                    now + self.ack_frequency.max_ack_delay,
-5517                    self.qlog.with_time(now),
-5518                );
-5519            }
-5520        }
-5521
-5522        // Issue stream ID credit due to ACKs of outgoing finish/resets and incoming finish/resets
-5523        // on stopped streams. Incoming finishes/resets on open streams are not handled here as they
-5524        // are only freed, and hence only issue credit, once the application has been notified
-5525        // during a read on the stream.
-5526        let pending = &mut self.spaces[SpaceId::Data].pending;
-5527        self.streams.queue_max_stream_id(pending);
-5528
-5529        if let Some(reason) = close {
-5530            self.state.move_to_draining(Some(reason.into()));
-5531            self.connection_close_pending = true;
-5532        }
-5533
-5534        // For Multipath any packet triggers migration. For RFC9000 or QNT (+ Multipath)
-5535        // only non-probing packets trigger migration.
-5536        let migrate_on_any_packet =
-5537            self.is_multipath_negotiated() && !self.n0_nat_traversal.is_negotiated();
-5538
-5539        // Only migrate if this is the largest packet number seen.
-5540        let is_largest_received_pn = Some(number)
-5541            == self.spaces[SpaceId::Data]
-5542                .for_path(path_id)
-5543                .largest_received_packet_number;
-5544
-5545        // If we receive a non-probing packet on a new local IP that means we had a NAT
-5546        // rebinding-like migration. We update our local address but do not otherwise
-5547        // validate the new path, we only need to validate the path if the peer migrates per
-5548        // RFC9000 §9: https://www.rfc-editor.org/rfc/rfc9000.html#section-9-4
-5549        if (migrate_on_any_packet || !is_probing_packet)
-5550            && is_largest_received_pn
-5551            && self.local_ip_may_migrate()
-5552            && let Some(new_local_ip) = network_path.local_ip
-5553        {
-5554            let path_data = self.path_data_mut(path_id);
-5555            if path_data
-5556                .network_path
-5557                .local_ip
-5558                .is_some_and(|ip| ip != new_local_ip)
-5559            {
-5560                debug!(
-5561                    %path_id,
-5562                    new_4tuple = %network_path,
-5563                    prev_4tuple = %path_data.network_path,
-5564                    "local address passive migration"
-5565                );
-5566            }
-5567            path_data.network_path.local_ip = Some(new_local_ip)
-5568        }
-5569
-5570        // If the peer migrated to a new address, trigger migration.
-5571        if (migrate_on_any_packet || !is_probing_packet)
-5572            && is_largest_received_pn
-5573            && network_path.remote != self.path_data(path_id).network_path.remote
-5574            && self.remote_may_migrate()
-5575        {
-5576            self.migrate(path_id, now, network_path, migration_observed_addr);
-5577            // Break linkability, if possible
-5578            self.update_remote_cid(path_id);
-5579            self.spin = false;
-5580        }
-5581
-5582        Ok(())
-5583    }
-5584
-5585    /// Migrates the 4-tuple of the path.
-5586    ///
-5587    /// This creates a new [`PathData`] for the migrated path and stores the previous
-5588    /// [`PathData`] in [`PathState::prev`].
-5589    fn migrate(
-5590        &mut self,
-5591        path_id: PathId,
-5592        now: Instant,
-5593        network_path: FourTuple,
-5594        observed_addr: Option<ObservedAddr>,
-5595    ) {
-5596        trace!(
-5597            new_4tuple = %network_path,
-5598            prev_4tuple = %self.path_data(path_id).network_path,
-5599            %path_id,
-5600            "migration initiated",
-5601        );
-5602        self.path_generation_counter = self.path_generation_counter.wrapping_add(1);
-5603        // TODO(@divma): conditions for path migration in multipath are very specific, check them
-5604        // again to prevent path migrations that should actually create a new path
-5605
-5606        // Reset rtt/congestion state for new path unless it looks like a NAT rebinding.
-5607        // Note that the congestion window will not grow until validation terminates. Helps mitigate
-5608        // amplification attacks performed by spoofing source addresses.
-5609        let prev_pto = self.pto(SpaceKind::Data, path_id);
-5610        let path = self.paths.get_mut(&path_id).expect("known path");
-5611        let mut new_path_data = if network_path.remote.is_ipv4()
-5612            && network_path.remote.ip() == path.data.network_path.remote.ip()
-5613        {
-5614            PathData::from_previous(network_path, &path.data, self.path_generation_counter, now)
-5615        } else {
-5616            let peer_max_udp_payload_size =
-5617                u16::try_from(self.peer_params.max_udp_payload_size.into_inner())
-5618                    .unwrap_or(u16::MAX);
-5619            PathData::new(
-5620                network_path,
-5621                self.allow_mtud,
-5622                Some(peer_max_udp_payload_size),
-5623                self.path_generation_counter,
-5624                now,
-5625                &self.config,
-5626            )
-5627        };
-5628        new_path_data.last_observed_addr_report = path.data.last_observed_addr_report.clone();
-5629        if let Some(report) = observed_addr
-5630            && let Some(updated) = new_path_data.update_observed_addr_report(report)
-5631        {
-5632            tracing::info!("adding observed addr event from migration");
-5633            self.events.push_back(Event::Path(PathEvent::ObservedAddr {
-5634                id: path_id,
-5635                addr: updated,
-5636            }));
-5637        }
-5638        new_path_data.pending_on_path_challenge = true;
-5639
-5640        let mut prev_path_data = mem::replace(&mut path.data, new_path_data);
-5641
-5642        // Only store this as previous path if it was validated. For all we know there could
-5643        // already be a previous path stored which might have been validated in the past,
-5644        // which is more valuable than one that's not yet validated.
-5645        //
-5646        // With multipath it is possible that there are no remote CIDs for the path ID
-5647        // yet. In this case we would never have sent on this path yet and would not be able
-5648        // to send a PATH_CHALLENGE either, which is currently a fire-and-forget affair
-5649        // anyway. So don't store such a path either.
-5650        if !prev_path_data.validated
-5651            && let Some(cid) = self.remote_cids.get(&path_id).map(CidQueue::active)
-5652        {
-5653            prev_path_data.pending_on_path_challenge = true;
-5654            // We haven't updated the remote CID yet, this captures the remote CID we were using on
-5655            // the previous path.
-5656            path.prev = Some((cid, prev_path_data));
-5657        }
-5658
-5659        // We need to re-assign the correct remote to this path in qlog
-5660        self.qlog.emit_tuple_assigned(path_id, network_path, now);
-5661
-5662        self.timers.set(
-5663            Timer::PerPath(path_id, PathTimer::PathValidationFailed),
-5664            now + 3 * cmp::max(self.pto(SpaceKind::Data, path_id), prev_pto),
-5665            self.qlog.with_time(now),
-5666        );
-5667    }
-5668
-5669    /// Handle a change in the local address, i.e. an active migration
-5670    ///
-5671    /// In the general (non-multipath) case, paths will perform a RFC9000 migration and be pinged
-5672    /// for a liveness check. This is the behaviour of a path assumed to be recoverable, even if
-5673    /// this is not the case.
-5674    ///
-5675    /// Clients in a connection in which multipath has been negotiated should migrate paths to new
-5676    /// [`PathId`]s. For paths that are known to be non-recoverable can be migrated to a new
-5677    /// [`PathId`] by closing the current path, and opening a new one to the same remote. Treating
-5678    /// paths as non recoverable when necessary accelerates connectivity re-establishment, or might
-5679    /// allow it altogether.
-5680    ///
-5681    /// The optional `hint` allows callers to indicate when paths are non-recoverable and should be
-5682    /// migrated to new a [`PathId`].
-5683    // NOTE: only clients are allowed to migrate, but generally dealing with RFC9000 migrations is
-5684    // lacking <https://github.com/n0-computer/noq/issues/364>
-5685    pub fn handle_network_change(&mut self, hint: Option<&dyn NetworkChangeHint>, now: Instant) {
-5686        debug!("network changed");
-5687        if self.state.is_drained() {
-5688            return;
-5689        }
-5690        if self.highest_space < SpaceKind::Data {
-5691            for path in self.paths.values_mut() {
-5692                // Clear the local address for it to be obtained from the socket again.
-5693                path.data.network_path.local_ip = None;
-5694            }
-5695
-5696            self.update_remote_cid(PathId::ZERO);
-5697            self.ping();
-5698
-5699            return;
-5700        }
-5701
-5702        // Paths that can't recover so a new path should be open instead. If multipath is not
-5703        // negotiated, this will be empty.
-5704        let mut non_recoverable_paths = Vec::default();
-5705        let mut recoverable_paths = Vec::default();
-5706        let mut open_paths = 0;
-5707
-5708        let is_multipath_negotiated = self.is_multipath_negotiated();
-5709        let is_client = self.side().is_client();
-5710        let immediate_ack_allowed = self.peer_supports_ack_frequency();
-5711
-5712        for (path_id, path) in self.paths.iter_mut() {
-5713            if self.abandoned_paths.contains(path_id) {
-5714                continue;
-5715            }
-5716            open_paths += 1;
-5717
-5718            // Read the network path BEFORE clearing local_ip, so the hint can
-5719            // check which interface the path was using.
-5720            let network_path = path.data.network_path;
-5721
-5722            // Clear the local address for it to be obtained from the socket again. This applies to
-5723            // all paths, regardless of being considered recoverable or not
-5724            path.data.network_path.local_ip = None;
-5725            let remote = network_path.remote;
-5726
-5727            // Without multipath, the connection tries to recover the single path, whereas with
-5728            // multipath, even in a single-path scenario, we attempt to migrate the path to a new
-5729            // PathId.
-5730            let attempt_to_recover = if is_multipath_negotiated {
-5731                // Use the hint to determine if the path can recover. When no hint is
-5732                // provided, clients default to non-recoverable (abandon and re-open)
-5733                // while servers default to recoverable (attempt in-place recovery).
-5734                hint.map(|h| h.is_path_recoverable(*path_id, network_path))
-5735                    .unwrap_or(!is_client)
-5736            } else {
-5737                // In the non multipath case, we try to recover the single active path
-5738                true
-5739            };
+5022                Frame::DataBlocked(DataBlocked(offset)) => {
+5023                    debug!(offset, "peer claims to be blocked at connection level");
+5024                }
+5025                Frame::StreamDataBlocked(StreamDataBlocked { id, offset }) => {
+5026                    if id.initiator() == self.side.side() && id.dir() == Dir::Uni {
+5027                        debug!("got STREAM_DATA_BLOCKED on send-only {}", id);
+5028                        return Err(TransportError::STREAM_STATE_ERROR(
+5029                            "STREAM_DATA_BLOCKED on send-only stream",
+5030                        ));
+5031                    }
+5032                    debug!(
+5033                        stream = %id,
+5034                        offset, "peer claims to be blocked at stream level"
+5035                    );
+5036                }
+5037                Frame::StreamsBlocked(StreamsBlocked { dir, limit }) => {
+5038                    if limit > MAX_STREAM_COUNT {
+5039                        return Err(TransportError::FRAME_ENCODING_ERROR(
+5040                            "unrepresentable stream limit",
+5041                        ));
+5042                    }
+5043                    debug!(
+5044                        "peer claims to be blocked opening more than {} {} streams",
+5045                        limit, dir
+5046                    );
+5047                }
+5048                Frame::StopSending(frame::StopSending { id, error_code }) => {
+5049                    if id.initiator() != self.side.side() {
+5050                        if id.dir() == Dir::Uni {
+5051                            debug!("got STOP_SENDING on recv-only {}", id);
+5052                            return Err(TransportError::STREAM_STATE_ERROR(
+5053                                "STOP_SENDING on recv-only stream",
+5054                            ));
+5055                        }
+5056                    } else if self.streams.is_local_unopened(id) {
+5057                        return Err(TransportError::STREAM_STATE_ERROR(
+5058                            "STOP_SENDING on unopened stream",
+5059                        ));
+5060                    }
+5061                    self.streams.received_stop_sending(id, error_code);
+5062                }
+5063                Frame::RetireConnectionId(frame::RetireConnectionId { path_id, sequence }) => {
+5064                    if let Some(ref path_id) = path_id {
+5065                        span.record("path", tracing::field::display(&path_id));
+5066                    }
+5067                    let path_id = path_id.unwrap_or_default();
+5068                    match self.local_cid_state.get_mut(&path_id) {
+5069                        None => error!(?path_id, "RETIRE_CONNECTION_ID for unknown path"),
+5070                        Some(cid_state) => {
+5071                            let allow_more_cids = cid_state
+5072                                .on_cid_retirement(sequence, self.peer_params.issue_cids_limit())?;
+5073
+5074                            // If the path has closed, we do not issue more CIDs for this path
+5075                            // For details see  https://www.ietf.org/archive/id/draft-ietf-quic-multipath-17.html#section-3.2.2
+5076                            // > an endpoint SHOULD provide new connection IDs for that path, if still open, using PATH_NEW_CONNECTION_ID frames.
+5077                            let has_path = !self.abandoned_paths.contains(&path_id);
+5078                            let allow_more_cids = allow_more_cids && has_path;
+5079
+5080                            debug_assert!(!self.state.is_drained()); // required for adding endpoint events, process_payload is never called for drained connections
+5081                            self.endpoint_events
+5082                                .push_back(EndpointEventInner::RetireConnectionId(
+5083                                    now,
+5084                                    path_id,
+5085                                    sequence,
+5086                                    allow_more_cids,
+5087                                ));
+5088                        }
+5089                    }
+5090                }
+5091                Frame::NewConnectionId(frame) => {
+5092                    let path_id = if let Some(path_id) = frame.path_id {
+5093                        if !self.is_multipath_negotiated() {
+5094                            return Err(TransportError::PROTOCOL_VIOLATION(
+5095                                "received PATH_NEW_CONNECTION_ID frame when multipath was not negotiated",
+5096                            ));
+5097                        }
+5098                        if path_id > self.local_max_path_id {
+5099                            return Err(TransportError::PROTOCOL_VIOLATION(
+5100                                "PATH_NEW_CONNECTION_ID contains path_id exceeding current max",
+5101                            ));
+5102                        }
+5103                        path_id
+5104                    } else {
+5105                        PathId::ZERO
+5106                    };
+5107
+5108                    if let Some(ref path_id) = frame.path_id {
+5109                        span.record("path", tracing::field::display(&path_id));
+5110                    }
+5111
+5112                    if self.abandoned_paths.contains(&path_id) {
+5113                        trace!("ignoring issued CID for abandoned path");
+5114                        continue;
+5115                    }
+5116                    let remote_cids = self
+5117                        .remote_cids
+5118                        .entry(path_id)
+5119                        .or_insert_with(|| CidQueue::new(frame.id));
+5120                    if remote_cids.active().is_empty() {
+5121                        return Err(TransportError::PROTOCOL_VIOLATION(
+5122                            "NEW_CONNECTION_ID when CIDs aren't in use",
+5123                        ));
+5124                    }
+5125                    if frame.retire_prior_to > frame.sequence {
+5126                        return Err(TransportError::PROTOCOL_VIOLATION(
+5127                            "NEW_CONNECTION_ID retiring unissued CIDs",
+5128                        ));
+5129                    }
+5130
+5131                    use crate::cid_queue::InsertError;
+5132                    match remote_cids.insert(frame) {
+5133                        Ok(None) => {
+5134                            self.open_nat_traversed_paths(now);
+5135                        }
+5136                        Ok(Some((retired, reset_token))) => {
+5137                            let pending_retired =
+5138                                &mut self.spaces[SpaceId::Data].pending.retire_cids;
+5139                            /// Ensure `pending_retired` cannot grow without bound. Limit is
+5140                            /// somewhat arbitrary but very permissive.
+5141                            const MAX_PENDING_RETIRED_CIDS: u64 = CidQueue::LEN as u64 * 10;
+5142                            // We don't bother counting in-flight frames because those are bounded
+5143                            // by congestion control.
+5144                            if (pending_retired.len() as u64)
+5145                                .saturating_add(retired.end.saturating_sub(retired.start))
+5146                                > MAX_PENDING_RETIRED_CIDS
+5147                            {
+5148                                return Err(TransportError::CONNECTION_ID_LIMIT_ERROR(
+5149                                    "queued too many retired CIDs",
+5150                                ));
+5151                            }
+5152                            pending_retired.extend(retired.map(|seq| (path_id, seq)));
+5153                            self.set_reset_token(path_id, network_path.remote, reset_token);
+5154                            self.open_nat_traversed_paths(now);
+5155                        }
+5156                        Err(InsertError::ExceedsLimit) => {
+5157                            return Err(TransportError::CONNECTION_ID_LIMIT_ERROR(""));
+5158                        }
+5159                        Err(InsertError::Retired) => {
+5160                            trace!("discarding already-retired");
+5161                            // RETIRE_CONNECTION_ID might not have been previously sent if e.g. a
+5162                            // range of connection IDs larger than the active connection ID limit
+5163                            // was retired all at once via retire_prior_to.
+5164                            self.spaces[SpaceId::Data]
+5165                                .pending
+5166                                .retire_cids
+5167                                .push((path_id, frame.sequence));
+5168                            continue;
+5169                        }
+5170                    };
+5171
+5172                    if self.side.is_server()
+5173                        && path_id == PathId::ZERO
+5174                        && self
+5175                            .remote_cids
+5176                            .get(&PathId::ZERO)
+5177                            .map(|cids| cids.active_seq() == 0)
+5178                            .unwrap_or_default()
+5179                    {
+5180                        // We're a server still using the initial remote CID for the client, so
+5181                        // let's switch immediately to enable clientside stateless resets.
+5182                        self.update_remote_cid(PathId::ZERO);
+5183                    }
+5184                }
+5185                Frame::NewToken(NewToken { token }) => {
+5186                    let ConnectionSide::Client {
+5187                        token_store,
+5188                        server_name,
+5189                        ..
+5190                    } = &self.side
+5191                    else {
+5192                        return Err(TransportError::PROTOCOL_VIOLATION("client sent NEW_TOKEN"));
+5193                    };
+5194                    if token.is_empty() {
+5195                        return Err(TransportError::FRAME_ENCODING_ERROR("empty token"));
+5196                    }
+5197                    trace!("got new token");
+5198                    token_store.insert(server_name, token);
+5199                }
+5200                Frame::Datagram(datagram) => {
+5201                    if self
+5202                        .datagrams
+5203                        .received(datagram, &self.config.datagram_receive_buffer_size)?
+5204                    {
+5205                        self.events.push_back(Event::DatagramReceived);
+5206                    }
+5207                }
+5208                Frame::AckFrequency(ack_frequency) => {
+5209                    // This frame can only be sent in the Data space
+5210
+5211                    if !self.ack_frequency.ack_frequency_received(&ack_frequency)? {
+5212                        // The AckFrequency frame is stale (we have already received a more
+5213                        // recent one)
+5214                        continue;
+5215                    }
+5216
+5217                    // Update the params for all of our paths
+5218                    for (path_id, space) in self.spaces[SpaceId::Data].number_spaces.iter_mut() {
+5219                        space.pending_acks.set_ack_frequency_params(&ack_frequency);
+5220
+5221                        // Our `max_ack_delay` has been updated, so we may need to adjust
+5222                        // its associated timeout.
+5223                        // Packets received on abandoned paths are always acknowledged immediately.
+5224                        if !self.abandoned_paths.contains(path_id)
+5225                            && let Some(timeout) = space
+5226                                .pending_acks
+5227                                .max_ack_delay_timeout(self.ack_frequency.max_ack_delay)
+5228                        {
+5229                            self.timers.set(
+5230                                Timer::PerPath(*path_id, PathTimer::MaxAckDelay),
+5231                                timeout,
+5232                                self.qlog.with_time(now),
+5233                            );
+5234                        }
+5235                    }
+5236                }
+5237                Frame::ImmediateAck => {
+5238                    // This frame can only be sent in the Data space
+5239                    for pns in self.spaces[SpaceId::Data].iter_paths_mut() {
+5240                        pns.pending_acks.set_immediate_ack_required();
+5241                    }
+5242                }
+5243                Frame::HandshakeDone => {
+5244                    if self.side.is_server() {
+5245                        return Err(TransportError::PROTOCOL_VIOLATION(
+5246                            "client sent HANDSHAKE_DONE",
+5247                        ));
+5248                    }
+5249                    if self.crypto_state.has_keys(EncryptionLevel::Handshake) {
+5250                        self.discard_space(now, SpaceKind::Handshake);
+5251                        self.events.push_back(Event::HandshakeConfirmed);
+5252                        trace!("handshake confirmed");
+5253                    }
+5254                }
+5255                Frame::ObservedAddr(observed) => {
+5256                    // check if params allows the peer to send report and this node to receive it
+5257                    trace!(seq_no = %observed.seq_no, ip = %observed.ip, port = observed.port);
+5258                    if !self
+5259                        .peer_params
+5260                        .address_discovery_role
+5261                        .should_report(&self.config.address_discovery_role)
+5262                    {
+5263                        return Err(TransportError::PROTOCOL_VIOLATION(
+5264                            "received OBSERVED_ADDRESS frame when not negotiated",
+5265                        ));
+5266                    }
+5267                    // must only be sent in data space
+5268                    if packet.header.space() != SpaceKind::Data {
+5269                        return Err(TransportError::PROTOCOL_VIOLATION(
+5270                            "OBSERVED_ADDRESS frame outside data space",
+5271                        ));
+5272                    }
+5273
+5274                    let path = self.path_data_mut(path_id);
+5275                    if network_path == path.network_path {
+5276                        if let Some(updated) = path.update_observed_addr_report(observed)
+5277                            && path.open_status == paths::OpenStatus::Informed
+5278                        {
+5279                            self.events.push_back(Event::Path(PathEvent::ObservedAddr {
+5280                                id: path_id,
+5281                                addr: updated,
+5282                            }));
+5283                            // otherwise the event is reported when the path is deemed open
+5284                        }
+5285                    } else {
+5286                        // include in migration
+5287                        migration_observed_addr = Some(observed)
+5288                    }
+5289                }
+5290                Frame::PathAbandon(frame::PathAbandon {
+5291                    path_id,
+5292                    error_code,
+5293                }) => {
+5294                    span.record("path", tracing::field::display(&path_id));
+5295                    match self.close_path_inner(
+5296                        now,
+5297                        path_id,
+5298                        PathAbandonReason::RemoteAbandoned {
+5299                            error_code: error_code.into(),
+5300                        },
+5301                    ) {
+5302                        Ok(()) => {
+5303                            trace!("peer abandoned path");
+5304                        }
+5305                        Err(ClosePathError::ClosedPath) => {
+5306                            trace!("peer abandoned already closed path");
+5307                        }
+5308                        Err(ClosePathError::MultipathNotNegotiated) => {
+5309                            return Err(TransportError::PROTOCOL_VIOLATION(
+5310                                "received PATH_ABANDON frame when multipath was not negotiated",
+5311                            ));
+5312                        }
+5313                        Err(ClosePathError::LastOpenPath) => {
+5314                            // Not reachable: close_path_inner allows remote abandons
+5315                            // for the last path. But handle gracefully just in case.
+5316                            error!(
+5317                                "peer abandoned last path but close_path_inner returned LastOpenPath"
+5318                            );
+5319                        }
+5320                    };
+5321
+5322                    // Start draining the path if it still exists and hasn't started draining yet.
+5323                    if let Some(path) = self.paths.get_mut(&path_id)
+5324                        && !mem::replace(&mut path.data.draining, true)
+5325                    {
+5326                        let ack_delay = self.ack_frequency.max_ack_delay_for_pto();
+5327                        let pto = path.data.rtt.pto_base() + ack_delay;
+5328                        self.timers.set(
+5329                            Timer::PerPath(path_id, PathTimer::PathDrained),
+5330                            now + 3 * pto,
+5331                            self.qlog.with_time(now),
+5332                        );
+5333
+5334                        self.set_max_path_id(now, self.local_max_path_id.saturating_add(1u8));
+5335                    }
+5336                }
+5337                Frame::PathStatusAvailable(info) => {
+5338                    span.record("path", tracing::field::display(&info.path_id));
+5339                    if self.is_multipath_negotiated() {
+5340                        self.on_path_status(
+5341                            info.path_id,
+5342                            PathStatus::Available,
+5343                            info.status_seq_no,
+5344                        );
+5345                    } else {
+5346                        return Err(TransportError::PROTOCOL_VIOLATION(
+5347                            "received PATH_STATUS_AVAILABLE frame when multipath was not negotiated",
+5348                        ));
+5349                    }
+5350                }
+5351                Frame::PathStatusBackup(info) => {
+5352                    span.record("path", tracing::field::display(&info.path_id));
+5353                    if self.is_multipath_negotiated() {
+5354                        self.on_path_status(info.path_id, PathStatus::Backup, info.status_seq_no);
+5355                    } else {
+5356                        return Err(TransportError::PROTOCOL_VIOLATION(
+5357                            "received PATH_STATUS_BACKUP frame when multipath was not negotiated",
+5358                        ));
+5359                    }
+5360                }
+5361                Frame::MaxPathId(frame::MaxPathId(path_id)) => {
+5362                    span.record("path", tracing::field::display(&path_id));
+5363                    if !self.is_multipath_negotiated() {
+5364                        return Err(TransportError::PROTOCOL_VIOLATION(
+5365                            "received MAX_PATH_ID frame when multipath was not negotiated",
+5366                        ));
+5367                    }
+5368                    // frames that do not increase the path id are ignored
+5369                    if path_id > self.remote_max_path_id {
+5370                        self.remote_max_path_id = path_id;
+5371                        self.issue_first_path_cids(now);
+5372                        self.open_nat_traversed_paths(now);
+5373                    }
+5374                }
+5375                Frame::PathsBlocked(frame::PathsBlocked(max_path_id)) => {
+5376                    // Receipt of a value of Maximum Path Identifier or Path Identifier that is higher than the local maximum value MUST
+5377                    // be treated as a connection error of type PROTOCOL_VIOLATION.
+5378                    // Ref <https://www.ietf.org/archive/id/draft-ietf-quic-multipath-14.html#name-paths_blocked-and-path_cids>
+5379                    if self.is_multipath_negotiated() {
+5380                        if max_path_id > self.local_max_path_id {
+5381                            return Err(TransportError::PROTOCOL_VIOLATION(
+5382                                "PATHS_BLOCKED maximum path identifier was larger than local maximum",
+5383                            ));
+5384                        }
+5385                        debug!("received PATHS_BLOCKED({:?})", max_path_id);
+5386                        // TODO(@divma): ensure max concurrent paths
+5387                    } else {
+5388                        return Err(TransportError::PROTOCOL_VIOLATION(
+5389                            "received PATHS_BLOCKED frame when not multipath was not negotiated",
+5390                        ));
+5391                    }
+5392                }
+5393                Frame::PathCidsBlocked(frame::PathCidsBlocked { path_id, next_seq }) => {
+5394                    // Nothing to do.  This is recorded in the frame stats, but otherwise we
+5395                    // always issue all CIDs we're allowed to issue, so either this is an
+5396                    // impatient peer or a bug on our side.
+5397
+5398                    // Receipt of a value of Maximum Path Identifier or Path Identifier that is higher than the local maximum value MUST
+5399                    // be treated as a connection error of type PROTOCOL_VIOLATION.
+5400                    // Ref <https://www.ietf.org/archive/id/draft-ietf-quic-multipath-14.html#name-paths_blocked-and-path_cids>
+5401                    if self.is_multipath_negotiated() {
+5402                        if path_id > self.local_max_path_id {
+5403                            return Err(TransportError::PROTOCOL_VIOLATION(
+5404                                "PATH_CIDS_BLOCKED path identifier was larger than local maximum",
+5405                            ));
+5406                        }
+5407                        if next_seq.0
+5408                            > self
+5409                                .local_cid_state
+5410                                .get(&path_id)
+5411                                .map(|cid_state| cid_state.active_seq().1 + 1)
+5412                                .unwrap_or_default()
+5413                        {
+5414                            return Err(TransportError::PROTOCOL_VIOLATION(
+5415                                "PATH_CIDS_BLOCKED next sequence number larger than in local state",
+5416                            ));
+5417                        }
+5418                        debug!(%path_id, %next_seq, "received PATH_CIDS_BLOCKED");
+5419                    } else {
+5420                        return Err(TransportError::PROTOCOL_VIOLATION(
+5421                            "received PATH_CIDS_BLOCKED frame when not multipath was not negotiated",
+5422                        ));
+5423                    }
+5424                }
+5425                Frame::AddAddress(addr) => {
+5426                    let client_state = match self.n0_nat_traversal.client_side_mut() {
+5427                        Ok(state) => state,
+5428                        Err(err) => {
+5429                            return Err(TransportError::PROTOCOL_VIOLATION(format!(
+5430                                "Nat traversal(ADD_ADDRESS): {err}"
+5431                            )));
+5432                        }
+5433                    };
+5434
+5435                    if !client_state.check_remote_address(&addr) {
+5436                        // if the address is not valid we flag it, but update anyway
+5437                        warn!(?addr, "server sent illegal ADD_ADDRESS frame");
+5438                    }
+5439
+5440                    match client_state.add_remote_address(addr) {
+5441                        Ok(maybe_added) => {
+5442                            if let Some(added) = maybe_added {
+5443                                self.events.push_back(Event::NatTraversal(
+5444                                    n0_nat_traversal::Event::AddressAdded(added),
+5445                                ));
+5446                            }
+5447                        }
+5448                        Err(e) => {
+5449                            warn!(%e, "failed to add remote address")
+5450                        }
+5451                    }
+5452                }
+5453                Frame::RemoveAddress(addr) => {
+5454                    let client_state = match self.n0_nat_traversal.client_side_mut() {
+5455                        Ok(state) => state,
+5456                        Err(err) => {
+5457                            return Err(TransportError::PROTOCOL_VIOLATION(format!(
+5458                                "Nat traversal(REMOVE_ADDRESS): {err}"
+5459                            )));
+5460                        }
+5461                    };
+5462                    if let Some(removed_addr) = client_state.remove_remote_address(addr) {
+5463                        self.events.push_back(Event::NatTraversal(
+5464                            n0_nat_traversal::Event::AddressRemoved(removed_addr),
+5465                        ));
+5466                    }
+5467                }
+5468                Frame::ReachOut(reach_out) => {
+5469                    let ipv6 = self.is_ipv6();
+5470                    let server_state = match self.n0_nat_traversal.server_side_mut() {
+5471                        Ok(state) => state,
+5472                        Err(err) => {
+5473                            return Err(TransportError::PROTOCOL_VIOLATION(format!(
+5474                                "Nat traversal(REACH_OUT): {err}"
+5475                            )));
+5476                        }
+5477                    };
+5478
+5479                    let round_before = server_state.current_round();
+5480
+5481                    if let Err(err) = server_state.handle_reach_out(reach_out, ipv6) {
+5482                        return Err(TransportError::PROTOCOL_VIOLATION(format!(
+5483                            "Nat traversal(REACH_OUT): {err}"
+5484                        )));
+5485                    }
+5486
+5487                    if server_state.current_round() > round_before {
+5488                        // A new round was started, reset the NAT probe retry timer.
+5489                        let delay = RttEstimator::new(self.config.initial_rtt).pto_base() * 2 / 3;
+5490                        self.timers.set(
+5491                            Timer::Conn(ConnTimer::NatTraversalProbeRetry),
+5492                            now + delay,
+5493                            self.qlog.with_time(now),
+5494                        );
+5495                    }
+5496                }
+5497            }
+5498        }
+5499
+5500        let space = self.spaces[SpaceId::Data].for_path(path_id);
+5501        if space
+5502            .pending_acks
+5503            .packet_received(now, number, ack_eliciting, &space.dedup)
+5504        {
+5505            if self.abandoned_paths.contains(&path_id) {
+5506                // § 3.4.3 QUIC-MULTIPATH: promptly send ACKs for packets received from
+5507                // abandoned paths.
+5508                space.pending_acks.set_immediate_ack_required();
+5509            } else {
+5510                self.timers.set(
+5511                    Timer::PerPath(path_id, PathTimer::MaxAckDelay),
+5512                    now + self.ack_frequency.max_ack_delay,
+5513                    self.qlog.with_time(now),
+5514                );
+5515            }
+5516        }
+5517
+5518        // Issue stream ID credit due to ACKs of outgoing finish/resets and incoming finish/resets
+5519        // on stopped streams. Incoming finishes/resets on open streams are not handled here as they
+5520        // are only freed, and hence only issue credit, once the application has been notified
+5521        // during a read on the stream.
+5522        let pending = &mut self.spaces[SpaceId::Data].pending;
+5523        self.streams.queue_max_stream_id(pending);
+5524
+5525        if let Some(reason) = close {
+5526            self.state.move_to_draining(Some(reason.into()));
+5527            self.connection_close_pending = true;
+5528        }
+5529
+5530        // For Multipath any packet triggers migration. For RFC9000 or QNT (+ Multipath)
+5531        // only non-probing packets trigger migration.
+5532        let migrate_on_any_packet =
+5533            self.is_multipath_negotiated() && !self.n0_nat_traversal.is_negotiated();
+5534
+5535        // Only migrate if this is the largest packet number seen.
+5536        let is_largest_received_pn = Some(number)
+5537            == self.spaces[SpaceId::Data]
+5538                .for_path(path_id)
+5539                .largest_received_packet_number;
+5540
+5541        // If we receive a non-probing packet on a new local IP that means we had a NAT
+5542        // rebinding-like migration. We update our local address but do not otherwise
+5543        // validate the new path, we only need to validate the path if the peer migrates per
+5544        // RFC9000 §9: https://www.rfc-editor.org/rfc/rfc9000.html#section-9-4
+5545        if (migrate_on_any_packet || !is_probing_packet)
+5546            && is_largest_received_pn
+5547            && self.local_ip_may_migrate()
+5548            && let Some(new_local_ip) = network_path.local_ip
+5549        {
+5550            let path_data = self.path_data_mut(path_id);
+5551            if path_data
+5552                .network_path
+5553                .local_ip
+5554                .is_some_and(|ip| ip != new_local_ip)
+5555            {
+5556                debug!(
+5557                    %path_id,
+5558                    new_4tuple = %network_path,
+5559                    prev_4tuple = %path_data.network_path,
+5560                    "local address passive migration"
+5561                );
+5562            }
+5563            path_data.network_path.local_ip = Some(new_local_ip)
+5564        }
+5565
+5566        // If the peer migrated to a new address, trigger migration.
+5567        if (migrate_on_any_packet || !is_probing_packet)
+5568            && is_largest_received_pn
+5569            && network_path.remote != self.path_data(path_id).network_path.remote
+5570            && self.remote_may_migrate()
+5571        {
+5572            self.migrate(path_id, now, network_path, migration_observed_addr);
+5573            // Break linkability, if possible
+5574            self.update_remote_cid(path_id);
+5575            self.spin = false;
+5576        }
+5577
+5578        Ok(())
+5579    }
+5580
+5581    /// Opens any paths that have been successfully NAT traversed.
+5582    fn open_nat_traversed_paths(&mut self, now: Instant) {
+5583        while let Some(network_path) = self
+5584            .n0_nat_traversal
+5585            .client_side_mut()
+5586            .ok()
+5587            .and_then(|s| s.pop_pending_path_open())
+5588        {
+5589            match self.open_path_ensure(network_path, PathStatus::Backup, now) {
+5590                Ok((path_id, already_existed)) => {
+5591                    debug!(
+5592                        %path_id,
+5593                        ?network_path,
+5594                        new_path = !already_existed,
+5595                        "Opened NAT traversal path",
+5596                    );
+5597                }
+5598                Err(err) => match err {
+5599                    PathError::MultipathNotNegotiated
+5600                    | PathError::ServerSideNotAllowed
+5601                    | PathError::ValidationFailed
+5602                    | PathError::InvalidRemoteAddress(_) => {
+5603                        error!(
+5604                            ?err,
+5605                            ?network_path,
+5606                            "Failed to open path for successful NAT traversal"
+5607                        );
+5608                    }
+5609                    PathError::MaxPathIdReached | PathError::RemoteCidsExhausted => {
+5610                        // Temporary error, put back.
+5611                        self.n0_nat_traversal
+5612                            .client_side_mut()
+5613                            .map(|s| s.push_pending_path_open(network_path))
+5614                            .ok();
+5615                        debug!(
+5616                            ?err,
+5617                            ?network_path,
+5618                            "Blocked opening NAT traversal path, enqueued"
+5619                        );
+5620                        return;
+5621                    }
+5622                },
+5623            }
+5624        }
+5625    }
+5626
+5627    /// Migrates the 4-tuple of the path.
+5628    ///
+5629    /// This creates a new [`PathData`] for the migrated path and stores the previous
+5630    /// [`PathData`] in [`PathState::prev`].
+5631    fn migrate(
+5632        &mut self,
+5633        path_id: PathId,
+5634        now: Instant,
+5635        network_path: FourTuple,
+5636        observed_addr: Option<ObservedAddr>,
+5637    ) {
+5638        trace!(
+5639            new_4tuple = %network_path,
+5640            prev_4tuple = %self.path_data(path_id).network_path,
+5641            %path_id,
+5642            "migration initiated",
+5643        );
+5644        self.path_generation_counter = self.path_generation_counter.wrapping_add(1);
+5645        // TODO(@divma): conditions for path migration in multipath are very specific, check them
+5646        // again to prevent path migrations that should actually create a new path
+5647
+5648        // Reset rtt/congestion state for new path unless it looks like a NAT rebinding.
+5649        // Note that the congestion window will not grow until validation terminates. Helps mitigate
+5650        // amplification attacks performed by spoofing source addresses.
+5651        let prev_pto = self.pto(SpaceKind::Data, path_id);
+5652        let path = self.paths.get_mut(&path_id).expect("known path");
+5653        let mut new_path_data = if network_path.remote.is_ipv4()
+5654            && network_path.remote.ip() == path.data.network_path.remote.ip()
+5655        {
+5656            PathData::from_previous(network_path, &path.data, self.path_generation_counter, now)
+5657        } else {
+5658            let peer_max_udp_payload_size =
+5659                u16::try_from(self.peer_params.max_udp_payload_size.into_inner())
+5660                    .unwrap_or(u16::MAX);
+5661            PathData::new(
+5662                network_path,
+5663                self.allow_mtud,
+5664                Some(peer_max_udp_payload_size),
+5665                self.path_generation_counter,
+5666                now,
+5667                &self.config,
+5668            )
+5669        };
+5670        new_path_data.last_observed_addr_report = path.data.last_observed_addr_report.clone();
+5671        if let Some(report) = observed_addr
+5672            && let Some(updated) = new_path_data.update_observed_addr_report(report)
+5673        {
+5674            tracing::info!("adding observed addr event from migration");
+5675            self.events.push_back(Event::Path(PathEvent::ObservedAddr {
+5676                id: path_id,
+5677                addr: updated,
+5678            }));
+5679        }
+5680        new_path_data.pending_on_path_challenge = true;
+5681
+5682        let mut prev_path_data = mem::replace(&mut path.data, new_path_data);
+5683
+5684        // Only store this as previous path if it was validated. For all we know there could
+5685        // already be a previous path stored which might have been validated in the past,
+5686        // which is more valuable than one that's not yet validated.
+5687        //
+5688        // With multipath it is possible that there are no remote CIDs for the path ID
+5689        // yet. In this case we would never have sent on this path yet and would not be able
+5690        // to send a PATH_CHALLENGE either, which is currently a fire-and-forget affair
+5691        // anyway. So don't store such a path either.
+5692        if !prev_path_data.validated
+5693            && let Some(cid) = self.remote_cids.get(&path_id).map(CidQueue::active)
+5694        {
+5695            prev_path_data.pending_on_path_challenge = true;
+5696            // We haven't updated the remote CID yet, this captures the remote CID we were using on
+5697            // the previous path.
+5698            path.prev = Some((cid, prev_path_data));
+5699        }
+5700
+5701        // We need to re-assign the correct remote to this path in qlog
+5702        self.qlog.emit_tuple_assigned(path_id, network_path, now);
+5703
+5704        self.timers.set(
+5705            Timer::PerPath(path_id, PathTimer::PathValidationFailed),
+5706            now + 3 * cmp::max(self.pto(SpaceKind::Data, path_id), prev_pto),
+5707            self.qlog.with_time(now),
+5708        );
+5709    }
+5710
+5711    /// Handle a change in the local address, i.e. an active migration
+5712    ///
+5713    /// In the general (non-multipath) case, paths will perform a RFC9000 migration and be pinged
+5714    /// for a liveness check. This is the behaviour of a path assumed to be recoverable, even if
+5715    /// this is not the case.
+5716    ///
+5717    /// Clients in a connection in which multipath has been negotiated should migrate paths to new
+5718    /// [`PathId`]s. For paths that are known to be non-recoverable can be migrated to a new
+5719    /// [`PathId`] by closing the current path, and opening a new one to the same remote. Treating
+5720    /// paths as non recoverable when necessary accelerates connectivity re-establishment, or might
+5721    /// allow it altogether.
+5722    ///
+5723    /// The optional `hint` allows callers to indicate when paths are non-recoverable and should be
+5724    /// migrated to new a [`PathId`].
+5725    // NOTE: only clients are allowed to migrate, but generally dealing with RFC9000 migrations is
+5726    // lacking <https://github.com/n0-computer/noq/issues/364>
+5727    pub fn handle_network_change(&mut self, hint: Option<&dyn NetworkChangeHint>, now: Instant) {
+5728        debug!("network changed");
+5729        if self.state.is_drained() {
+5730            return;
+5731        }
+5732        if self.highest_space < SpaceKind::Data {
+5733            for path in self.paths.values_mut() {
+5734                // Clear the local address for it to be obtained from the socket again.
+5735                path.data.network_path.local_ip = None;
+5736            }
+5737
+5738            self.update_remote_cid(PathId::ZERO);
+5739            self.ping();
 5740
-5741            if attempt_to_recover {
-5742                recoverable_paths.push((*path_id, remote));
-5743            } else {
-5744                non_recoverable_paths.push((*path_id, remote, path.data.local_status()))
-5745            }
-5746        }
-5747
-5748        /* NON RECOVERABLE PATHS */
-5749        // This are handled first, so that in case the treatment intended for these fails, we can
-5750        // go the recoverable route instead.
-5751
-5752        // Decide if we need to close first or open first in the multipath case.
-5753        // - Opening first has a higher risk of getting limited by the negotiated MAX_PATH_ID.
-5754        // - Closing first risks this being the only open path.
-5755        // We prefer closing paths first unless we identify this is the last open path.
-5756        let open_first = open_paths == non_recoverable_paths.len();
-5757
-5758        for (path_id, remote, status) in non_recoverable_paths.into_iter() {
-5759            let network_path = FourTuple {
-5760                remote,
-5761                local_ip: None, /* allow the local ip to be discovered */
-5762            };
+5741            return;
+5742        }
+5743
+5744        // Paths that can't recover so a new path should be open instead. If multipath is not
+5745        // negotiated, this will be empty.
+5746        let mut non_recoverable_paths = Vec::default();
+5747        let mut recoverable_paths = Vec::default();
+5748        let mut open_paths = 0;
+5749
+5750        let is_multipath_negotiated = self.is_multipath_negotiated();
+5751        let is_client = self.side().is_client();
+5752        let immediate_ack_allowed = self.peer_supports_ack_frequency();
+5753
+5754        for (path_id, path) in self.paths.iter_mut() {
+5755            if self.abandoned_paths.contains(path_id) {
+5756                continue;
+5757            }
+5758            open_paths += 1;
+5759
+5760            // Read the network path BEFORE clearing local_ip, so the hint can
+5761            // check which interface the path was using.
+5762            let network_path = path.data.network_path;
 5763
-5764            if open_first && let Err(e) = self.open_path(network_path, status, now) {
-5765                if self.side().is_client() {
-5766                    debug!(%e, "Failed to open new path for network change");
-5767                }
-5768                // if this fails, let the path try to recover itself
-5769                recoverable_paths.push((path_id, remote));
-5770                continue;
-5771            }
-5772
-5773            if let Err(e) =
-5774                self.close_path_inner(now, path_id, PathAbandonReason::UnusableAfterNetworkChange)
-5775            {
-5776                debug!(%e,"Failed to close unrecoverable path after network change");
-5777                recoverable_paths.push((path_id, remote));
-5778                continue;
-5779            }
-5780
-5781            if !open_first && let Err(e) = self.open_path(network_path, status, now) {
-5782                // Path has already been closed if we got here. Since the path was not recoverable,
-5783                // this might be desirable in any case, because other paths exist (!open_first) and
-5784                // this was is considered non recoverable
-5785                debug!(%e,"Failed to open new path for network change");
-5786            }
-5787        }
-5788
-5789        /* RECOVERABLE PATHS */
-5790
-5791        for (path_id, remote) in recoverable_paths.into_iter() {
-5792            // Schedule a Ping for a liveness check.
-5793            if let Some(path_space) = self.spaces[SpaceId::Data].number_spaces.get_mut(&path_id) {
-5794                path_space.ping_pending = true;
-5795
-5796                if immediate_ack_allowed {
-5797                    path_space.immediate_ack_pending = true;
-5798                }
-5799            }
-5800
-5801            // Reset PTO backoff so retransmits resume promptly. Congestion controller and
-5802            // RTT are intentionally preserved for recoverable paths. We explicitly allow
-5803            // this reset also during the handshake, so do not check
-5804            // Self::peer_competed_handshake_address_validation.
-5805            if let Some(path) = self.paths.get_mut(&path_id) {
-5806                path.data.pto_count = 0;
-5807            }
-5808            self.set_loss_detection_timer(now, path_id);
-5809
-5810            let Some((reset_token, retired)) =
-5811                self.remote_cids.get_mut(&path_id).and_then(CidQueue::next)
-5812            else {
-5813                continue;
-5814            };
-5815
-5816            // Retire the current remote CID and any CIDs we had to skip.
-5817            self.spaces[SpaceId::Data]
-5818                .pending
-5819                .retire_cids
-5820                .extend(retired.map(|seq| (path_id, seq)));
-5821
-5822            debug_assert!(!self.state.is_drained()); // required for endpoint_events, checked above
-5823            self.endpoint_events
-5824                .push_back(EndpointEventInner::ResetToken(path_id, remote, reset_token));
-5825        }
-5826    }
-5827
-5828    /// Switch to a previously unused remote connection ID, if possible
-5829    fn update_remote_cid(&mut self, path_id: PathId) {
-5830        let Some((reset_token, retired)) = self
-5831            .remote_cids
-5832            .get_mut(&path_id)
-5833            .and_then(|cids| cids.next())
-5834        else {
-5835            return;
-5836        };
+5764            // Clear the local address for it to be obtained from the socket again. This applies to
+5765            // all paths, regardless of being considered recoverable or not
+5766            path.data.network_path.local_ip = None;
+5767            let remote = network_path.remote;
+5768
+5769            // Without multipath, the connection tries to recover the single path, whereas with
+5770            // multipath, even in a single-path scenario, we attempt to migrate the path to a new
+5771            // PathId.
+5772            let attempt_to_recover = if is_multipath_negotiated {
+5773                // Use the hint to determine if the path can recover. When no hint is
+5774                // provided, clients default to non-recoverable (abandon and re-open)
+5775                // while servers default to recoverable (attempt in-place recovery).
+5776                hint.map(|h| h.is_path_recoverable(*path_id, network_path))
+5777                    .unwrap_or(!is_client)
+5778            } else {
+5779                // In the non multipath case, we try to recover the single active path
+5780                true
+5781            };
+5782
+5783            if attempt_to_recover {
+5784                recoverable_paths.push((*path_id, remote));
+5785            } else {
+5786                non_recoverable_paths.push((*path_id, remote, path.data.local_status()))
+5787            }
+5788        }
+5789
+5790        /* NON RECOVERABLE PATHS */
+5791        // This are handled first, so that in case the treatment intended for these fails, we can
+5792        // go the recoverable route instead.
+5793
+5794        // Decide if we need to close first or open first in the multipath case.
+5795        // - Opening first has a higher risk of getting limited by the negotiated MAX_PATH_ID.
+5796        // - Closing first risks this being the only open path.
+5797        // We prefer closing paths first unless we identify this is the last open path.
+5798        let open_first = open_paths == non_recoverable_paths.len();
+5799
+5800        for (path_id, remote, status) in non_recoverable_paths.into_iter() {
+5801            let network_path = FourTuple {
+5802                remote,
+5803                local_ip: None, /* allow the local ip to be discovered */
+5804            };
+5805
+5806            if open_first && let Err(e) = self.open_path(network_path, status, now) {
+5807                if self.side().is_client() {
+5808                    debug!(%e, "Failed to open new path for network change");
+5809                }
+5810                // if this fails, let the path try to recover itself
+5811                recoverable_paths.push((path_id, remote));
+5812                continue;
+5813            }
+5814
+5815            if let Err(e) =
+5816                self.close_path_inner(now, path_id, PathAbandonReason::UnusableAfterNetworkChange)
+5817            {
+5818                debug!(%e,"Failed to close unrecoverable path after network change");
+5819                recoverable_paths.push((path_id, remote));
+5820                continue;
+5821            }
+5822
+5823            if !open_first && let Err(e) = self.open_path(network_path, status, now) {
+5824                // Path has already been closed if we got here. Since the path was not recoverable,
+5825                // this might be desirable in any case, because other paths exist (!open_first) and
+5826                // this was is considered non recoverable
+5827                debug!(%e,"Failed to open new path for network change");
+5828            }
+5829        }
+5830
+5831        /* RECOVERABLE PATHS */
+5832
+5833        for (path_id, remote) in recoverable_paths.into_iter() {
+5834            // Schedule a Ping for a liveness check.
+5835            if let Some(path_space) = self.spaces[SpaceId::Data].number_spaces.get_mut(&path_id) {
+5836                path_space.ping_pending = true;
 5837
-5838        // Retire the current remote CID and any CIDs we had to skip.
-5839        self.spaces[SpaceId::Data]
-5840            .pending
-5841            .retire_cids
-5842            .extend(retired.map(|seq| (path_id, seq)));
-5843        let remote = self.path_data(path_id).network_path.remote;
-5844        self.set_reset_token(path_id, remote, reset_token);
-5845    }
-5846
-5847    /// Sends this reset token to the endpoint
-5848    ///
-5849    /// The endpoint needs to know the reset tokens issued by the peer, so that if the peer
-5850    /// sends a reset token it knows to route it to this connection. See RFC 9000 section
-5851    /// 10.3. Stateless Reset.
-5852    ///
-5853    /// Reset tokens are different for each path, the endpoint identifies paths by peer
-5854    /// socket address however, not by path ID.
-5855    fn set_reset_token(&mut self, path_id: PathId, remote: SocketAddr, reset_token: ResetToken) {
-5856        debug_assert!(!self.state.is_drained()); // required for endpoint events, set_reset_token is never called for drained connections
-5857        self.endpoint_events
-5858            .push_back(EndpointEventInner::ResetToken(path_id, remote, reset_token));
-5859
-5860        // During the handshake the server sends a reset token in the transport
-5861        // parameters. When we are the client and we receive the reset token during the
-5862        // handshake we want this to affect our peer transport parameters.
-5863        // TODO(flub): Pretty sure this is pointless, the entire params is overwritten
-5864        //    shortly after this was called.  And then the params don't have this anymore.
-5865        if path_id == PathId::ZERO {
-5866            self.peer_params.stateless_reset_token = Some(reset_token);
+5838                if immediate_ack_allowed {
+5839                    path_space.immediate_ack_pending = true;
+5840                }
+5841            }
+5842
+5843            // Reset PTO backoff so retransmits resume promptly. Congestion controller and
+5844            // RTT are intentionally preserved for recoverable paths. We explicitly allow
+5845            // this reset also during the handshake, so do not check
+5846            // Self::peer_competed_handshake_address_validation.
+5847            if let Some(path) = self.paths.get_mut(&path_id) {
+5848                path.data.pto_count = 0;
+5849            }
+5850            self.set_loss_detection_timer(now, path_id);
+5851
+5852            let Some((reset_token, retired)) =
+5853                self.remote_cids.get_mut(&path_id).and_then(CidQueue::next)
+5854            else {
+5855                continue;
+5856            };
+5857
+5858            // Retire the current remote CID and any CIDs we had to skip.
+5859            self.spaces[SpaceId::Data]
+5860                .pending
+5861                .retire_cids
+5862                .extend(retired.map(|seq| (path_id, seq)));
+5863
+5864            debug_assert!(!self.state.is_drained()); // required for endpoint_events, checked above
+5865            self.endpoint_events
+5866                .push_back(EndpointEventInner::ResetToken(path_id, remote, reset_token));
 5867        }
 5868    }
 5869
-5870    /// Issue an initial set of connection IDs to the peer upon connection
-5871    fn issue_first_cids(&mut self, now: Instant) {
-5872        if self
-5873            .local_cid_state
-5874            .get(&PathId::ZERO)
-5875            .expect("PathId::ZERO exists when the connection is created")
-5876            .cid_len()
-5877            == 0
-5878        {
-5879            return;
-5880        }
-5881
-5882        // Subtract 1 to account for the CID we supplied while handshaking
-5883        let mut n = self.peer_params.issue_cids_limit() - 1;
-5884        if let ConnectionSide::Server { server_config } = &self.side
-5885            && server_config.has_preferred_address()
-5886        {
-5887            // We also sent a CID in the transport parameters
-5888            n -= 1;
-5889        }
-5890        debug_assert!(!self.state.is_drained()); // requirement for endpoint_events
-5891        self.endpoint_events
-5892            .push_back(EndpointEventInner::NeedIdentifiers(PathId::ZERO, now, n));
-5893    }
-5894
-5895    /// Issues an initial set of CIDs for paths that have not yet had any CIDs issued
-5896    ///
-5897    /// Later CIDs are issued when CIDs expire or are retired by the peer.
-5898    fn issue_first_path_cids(&mut self, now: Instant) {
-5899        if let Some(max_path_id) = self.max_path_id() {
-5900            let mut path_id = self.max_path_id_with_cids.next();
-5901            while path_id <= max_path_id {
-5902                self.endpoint_events
-5903                    .push_back(EndpointEventInner::NeedIdentifiers(
-5904                        path_id,
-5905                        now,
-5906                        self.peer_params.issue_cids_limit(),
-5907                    ));
-5908                path_id = path_id.next();
-5909            }
-5910            self.max_path_id_with_cids = max_path_id;
-5911        }
-5912    }
-5913
-5914    /// Populates a packet with frames
-5915    ///
-5916    /// This tries to fit as many frames as possible into the packet.
-5917    ///
-5918    /// *path_exclusive_only* means to only build frames which can only be sent on this
-5919    /// *path.  This is used in multipath for backup paths while there is still an active
-5920    /// *path.
-5921    fn populate_packet<'a, 'b>(
-5922        &mut self,
-5923        now: Instant,
-5924        space_id: SpaceId,
-5925        path_id: PathId,
-5926        scheduling_info: &PathSchedulingInfo,
-5927        builder: &mut PacketBuilder<'a, 'b>,
-5928    ) {
-5929        let is_multipath_negotiated = self.is_multipath_negotiated();
-5930        let space_has_keys = self.crypto_state.has_keys(space_id.encryption_level());
-5931        let is_0rtt = space_id == SpaceId::Data && !space_has_keys;
-5932        let stats = &mut self.path_stats.for_path(path_id).frame_tx;
-5933        let space = &mut self.spaces[space_id];
-5934        let path = &mut self.paths.get_mut(&path_id).expect("known path").data;
-5935        space
-5936            .for_path(path_id)
-5937            .pending_acks
-5938            .maybe_ack_non_eliciting();
-5939
-5940        // HANDSHAKE_DONE
-5941        if !is_0rtt
-5942            && !scheduling_info.is_abandoned
-5943            && scheduling_info.may_send_data
-5944            && mem::replace(&mut space.pending.handshake_done, false)
-5945        {
-5946            builder.write_frame(frame::HandshakeDone, stats);
-5947        }
-5948
-5949        // PING
-5950        if !scheduling_info.is_abandoned
-5951            && mem::replace(&mut space.for_path(path_id).ping_pending, false)
-5952        {
-5953            builder.write_frame(frame::Ping, stats);
-5954        }
+5870    /// Switch to a previously unused remote connection ID, if possible
+5871    fn update_remote_cid(&mut self, path_id: PathId) {
+5872        let Some((reset_token, retired)) = self
+5873            .remote_cids
+5874            .get_mut(&path_id)
+5875            .and_then(|cids| cids.next())
+5876        else {
+5877            return;
+5878        };
+5879
+5880        // Retire the current remote CID and any CIDs we had to skip.
+5881        self.spaces[SpaceId::Data]
+5882            .pending
+5883            .retire_cids
+5884            .extend(retired.map(|seq| (path_id, seq)));
+5885        let remote = self.path_data(path_id).network_path.remote;
+5886        self.set_reset_token(path_id, remote, reset_token);
+5887    }
+5888
+5889    /// Sends this reset token to the endpoint
+5890    ///
+5891    /// The endpoint needs to know the reset tokens issued by the peer, so that if the peer
+5892    /// sends a reset token it knows to route it to this connection. See RFC 9000 section
+5893    /// 10.3. Stateless Reset.
+5894    ///
+5895    /// Reset tokens are different for each path, the endpoint identifies paths by peer
+5896    /// socket address however, not by path ID.
+5897    fn set_reset_token(&mut self, path_id: PathId, remote: SocketAddr, reset_token: ResetToken) {
+5898        debug_assert!(!self.state.is_drained()); // required for endpoint events, set_reset_token is never called for drained connections
+5899        self.endpoint_events
+5900            .push_back(EndpointEventInner::ResetToken(path_id, remote, reset_token));
+5901
+5902        // During the handshake the server sends a reset token in the transport
+5903        // parameters. When we are the client and we receive the reset token during the
+5904        // handshake we want this to affect our peer transport parameters.
+5905        // TODO(flub): Pretty sure this is pointless, the entire params is overwritten
+5906        //    shortly after this was called.  And then the params don't have this anymore.
+5907        if path_id == PathId::ZERO {
+5908            self.peer_params.stateless_reset_token = Some(reset_token);
+5909        }
+5910    }
+5911
+5912    /// Issue an initial set of connection IDs to the peer upon connection
+5913    fn issue_first_cids(&mut self, now: Instant) {
+5914        if self
+5915            .local_cid_state
+5916            .get(&PathId::ZERO)
+5917            .expect("PathId::ZERO exists when the connection is created")
+5918            .cid_len()
+5919            == 0
+5920        {
+5921            return;
+5922        }
+5923
+5924        // Subtract 1 to account for the CID we supplied while handshaking
+5925        let mut n = self.peer_params.issue_cids_limit() - 1;
+5926        if let ConnectionSide::Server { server_config } = &self.side
+5927            && server_config.has_preferred_address()
+5928        {
+5929            // We also sent a CID in the transport parameters
+5930            n -= 1;
+5931        }
+5932        debug_assert!(!self.state.is_drained()); // requirement for endpoint_events
+5933        self.endpoint_events
+5934            .push_back(EndpointEventInner::NeedIdentifiers(PathId::ZERO, now, n));
+5935    }
+5936
+5937    /// Issues an initial set of CIDs for paths that have not yet had any CIDs issued
+5938    ///
+5939    /// Later CIDs are issued when CIDs expire or are retired by the peer.
+5940    fn issue_first_path_cids(&mut self, now: Instant) {
+5941        if let Some(max_path_id) = self.max_path_id() {
+5942            let mut path_id = self.max_path_id_with_cids.next();
+5943            while path_id <= max_path_id {
+5944                self.endpoint_events
+5945                    .push_back(EndpointEventInner::NeedIdentifiers(
+5946                        path_id,
+5947                        now,
+5948                        self.peer_params.issue_cids_limit(),
+5949                    ));
+5950                path_id = path_id.next();
+5951            }
+5952            self.max_path_id_with_cids = max_path_id;
+5953        }
+5954    }
 5955
-5956        // IMMEDIATE_ACK
-5957        if !scheduling_info.is_abandoned
-5958            && mem::replace(&mut space.for_path(path_id).immediate_ack_pending, false)
-5959        {
-5960            debug_assert_eq!(
-5961                space_id,
-5962                SpaceId::Data,
-5963                "immediate acks must be sent in the data space"
-5964            );
-5965            builder.write_frame(frame::ImmediateAck, stats);
-5966        }
-5967
-5968        // ACK
-5969        if !scheduling_info.is_abandoned && scheduling_info.may_send_data {
-5970            for path_id in space
-5971                .number_spaces
-5972                .iter_mut()
-5973                .filter(|(_, pns)| pns.pending_acks.can_send())
-5974                .map(|(&path_id, _)| path_id)
-5975                .collect::<Vec<_>>()
-5976            {
-5977                Self::populate_acks(
-5978                    now,
-5979                    self.receiving_ecn,
-5980                    path_id,
-5981                    space_id,
-5982                    space,
-5983                    is_multipath_negotiated,
-5984                    builder,
-5985                    stats,
-5986                    space_has_keys,
-5987                );
-5988            }
+5956    /// Populates a packet with frames
+5957    ///
+5958    /// This tries to fit as many frames as possible into the packet.
+5959    ///
+5960    /// *path_exclusive_only* means to only build frames which can only be sent on this
+5961    /// *path.  This is used in multipath for backup paths while there is still an active
+5962    /// *path.
+5963    fn populate_packet<'a, 'b>(
+5964        &mut self,
+5965        now: Instant,
+5966        space_id: SpaceId,
+5967        path_id: PathId,
+5968        scheduling_info: &PathSchedulingInfo,
+5969        builder: &mut PacketBuilder<'a, 'b>,
+5970    ) {
+5971        let is_multipath_negotiated = self.is_multipath_negotiated();
+5972        let space_has_keys = self.crypto_state.has_keys(space_id.encryption_level());
+5973        let is_0rtt = space_id == SpaceId::Data && !space_has_keys;
+5974        let stats = &mut self.path_stats.for_path(path_id).frame_tx;
+5975        let space = &mut self.spaces[space_id];
+5976        let path = &mut self.paths.get_mut(&path_id).expect("known path").data;
+5977        space
+5978            .for_path(path_id)
+5979            .pending_acks
+5980            .maybe_ack_non_eliciting();
+5981
+5982        // HANDSHAKE_DONE
+5983        if !is_0rtt
+5984            && !scheduling_info.is_abandoned
+5985            && scheduling_info.may_send_data
+5986            && mem::replace(&mut space.pending.handshake_done, false)
+5987        {
+5988            builder.write_frame(frame::HandshakeDone, stats);
 5989        }
 5990
-5991        // ACK_FREQUENCY
+5991        // PING
 5992        if !scheduling_info.is_abandoned
-5993            && scheduling_info.may_send_data
-5994            && mem::replace(&mut space.pending.ack_frequency, false)
-5995        {
-5996            let sequence_number = self.ack_frequency.next_sequence_number();
+5993            && mem::replace(&mut space.for_path(path_id).ping_pending, false)
+5994        {
+5995            builder.write_frame(frame::Ping, stats);
+5996        }
 5997
-5998            // Safe to unwrap because this is always provided when ACK frequency is enabled
-5999            let config = self.config.ack_frequency_config.as_ref().unwrap();
-6000
-6001            // Ensure the delay is within bounds to avoid a PROTOCOL_VIOLATION error
-6002            let max_ack_delay = self.ack_frequency.candidate_max_ack_delay(
-6003                path.rtt.get(),
-6004                config,
-6005                &self.peer_params,
-6006            );
-6007
-6008            let frame = frame::AckFrequency {
-6009                sequence: sequence_number,
-6010                ack_eliciting_threshold: config.ack_eliciting_threshold,
-6011                request_max_ack_delay: max_ack_delay.as_micros().try_into().unwrap_or(VarInt::MAX),
-6012                reordering_threshold: config.reordering_threshold,
-6013            };
-6014            builder.write_frame(frame, stats);
-6015
-6016            self.ack_frequency
-6017                .ack_frequency_sent(path_id, builder.packet_number, max_ack_delay);
-6018        }
-6019
-6020        // PATH_CHALLENGE
-6021        if !scheduling_info.is_abandoned
-6022            && space_id == SpaceId::Data
-6023            && path.pending_on_path_challenge
-6024            && !self.state.is_closed()
-6025            && builder.frame_space_remaining() > frame::PathChallenge::SIZE_BOUND
-6026        // we don't want to send new challenges if we are already closing
-6027        {
-6028            path.pending_on_path_challenge = false;
-6029
-6030            let token = self.rng.random();
-6031            path.record_path_challenge_sent(now, token, path.network_path);
-6032            // Generate a new challenge every time we send a new PATH_CHALLENGE
-6033            let challenge = frame::PathChallenge(token);
-6034            builder.write_frame(challenge, stats);
-6035            builder.require_padding();
-6036            let pto = self.ack_frequency.max_ack_delay_for_pto() + path.rtt.pto_base();
-6037            match path.open_status {
-6038                paths::OpenStatus::Sent | paths::OpenStatus::Informed => {}
-6039                paths::OpenStatus::Pending => {
-6040                    path.open_status = paths::OpenStatus::Sent;
-6041                    self.timers.set(
-6042                        Timer::PerPath(path_id, PathTimer::AbandonFromValidation),
-6043                        now + 3 * pto,
-6044                        self.qlog.with_time(now),
-6045                    );
-6046                }
-6047                // The path open status was informed before, we just want to revalidate again.
-6048                // For that, we want to make sure we set the PathOpenFailed timer again.
-6049                paths::OpenStatus::Revalidating => {
-6050                    path.open_status = paths::OpenStatus::Informed;
-6051                    self.timers.set(
-6052                        Timer::PerPath(path_id, PathTimer::AbandonFromValidation),
-6053                        now + 3 * pto,
-6054                        self.qlog.with_time(now),
-6055                    );
-6056                }
-6057            }
-6058
-6059            self.timers.set(
-6060                Timer::PerPath(path_id, PathTimer::PathChallengeLost),
-6061                now + pto,
-6062                self.qlog.with_time(now),
-6063            );
-6064
-6065            if is_multipath_negotiated && !path.validated && path.pending_on_path_challenge {
-6066                // queue informing the path status along with the challenge
-6067                space.pending.path_status.insert(path_id);
-6068            }
-6069
-6070            // Always include an OBSERVED_ADDR frame with a PATH_CHALLENGE, regardless
-6071            // of whether one has already been sent on this path.
-6072            if space_id == SpaceId::Data
-6073                && self
-6074                    .config
-6075                    .address_discovery_role
-6076                    .should_report(&self.peer_params.address_discovery_role)
-6077            {
-6078                let frame = frame::ObservedAddr::new(
-6079                    path.network_path.remote,
-6080                    self.next_observed_addr_seq_no,
-6081                );
-6082                if builder.frame_space_remaining() > frame.size() {
-6083                    builder.write_frame(frame, stats);
-6084
-6085                    self.next_observed_addr_seq_no =
-6086                        self.next_observed_addr_seq_no.saturating_add(1u8);
-6087                    path.observed_addr_sent = true;
-6088
-6089                    space.pending.observed_addr = false;
-6090                }
-6091            }
-6092        }
-6093
-6094        // PATH_RESPONSE
-6095        if !scheduling_info.is_abandoned
-6096            && space_id == SpaceId::Data
-6097            && builder.frame_space_remaining() > frame::PathResponse::SIZE_BOUND
-6098            && let Some(token) = path.path_responses.pop_on_path(path.network_path)
-6099        {
-6100            let response = frame::PathResponse(token);
-6101            builder.write_frame(response, stats);
-6102            builder.require_padding();
-6103
-6104            // NOTE: this is technically not required but might be useful to ride the
-6105            // request/response nature of path challenges to refresh an observation
-6106            // Since PATH_RESPONSE is a probing frame, this is allowed by the spec.
-6107            if space_id == SpaceId::Data
-6108                && self
-6109                    .config
-6110                    .address_discovery_role
-6111                    .should_report(&self.peer_params.address_discovery_role)
-6112            {
-6113                let frame = frame::ObservedAddr::new(
-6114                    path.network_path.remote,
-6115                    self.next_observed_addr_seq_no,
-6116                );
-6117                if builder.frame_space_remaining() > frame.size() {
-6118                    builder.write_frame(frame, stats);
-6119
-6120                    self.next_observed_addr_seq_no =
-6121                        self.next_observed_addr_seq_no.saturating_add(1u8);
-6122                    path.observed_addr_sent = true;
-6123
-6124                    space.pending.observed_addr = false;
-6125                }
-6126            }
-6127        }
-6128
-6129        // REACH_OUT
-6130        if !scheduling_info.is_abandoned
-6131            && scheduling_info.may_send_data
-6132            && let Some((round, addresses)) = space.pending.reach_out.as_mut()
-6133        {
-6134            while let Some(local_addr) = addresses.iter().next().copied() {
-6135                let local_addr = addresses.take(&local_addr).expect("found from iter");
-6136                let reach_out = frame::ReachOut::new(*round, local_addr);
-6137                if builder.frame_space_remaining() > reach_out.size() {
-6138                    builder.write_frame(reach_out, stats);
-6139                } else {
-6140                    addresses.insert(local_addr);
-6141                    break;
-6142                }
-6143            }
-6144            if addresses.is_empty() {
-6145                space.pending.reach_out = None;
-6146            }
-6147        }
-6148
-6149        // PATH_ABANDON
-6150        if space_id == SpaceId::Data
-6151            && scheduling_info.is_abandoned
-6152            && scheduling_info.may_self_abandon
-6153            && frame::PathAbandon::SIZE_BOUND <= builder.frame_space_remaining()
-6154            && let Some(error_code) = space.pending.path_abandon.remove(&path_id)
-6155        {
-6156            let frame = frame::PathAbandon {
-6157                path_id,
-6158                error_code,
-6159            };
-6160            builder.write_frame(frame, stats);
-6161
-6162            // Consider remotely issued CIDs as retired now that we have sent this frame at
-6163            // least once.
-6164            self.remote_cids.remove(&path_id);
-6165        }
-6166        while space_id == SpaceId::Data
-6167            && scheduling_info.may_send_data
-6168            && frame::PathAbandon::SIZE_BOUND <= builder.frame_space_remaining()
-6169            && let Some((abandoned_path_id, error_code)) = space.pending.path_abandon.pop_first()
-6170        {
-6171            let frame = frame::PathAbandon {
-6172                path_id: abandoned_path_id,
-6173                error_code,
-6174            };
-6175            builder.write_frame(frame, stats);
-6176
-6177            // Consider remotely issued CIDs as retired now that we have sent this frame at
-6178            // least once.
-6179            self.remote_cids.remove(&abandoned_path_id);
-6180        }
-6181
-6182        // OBSERVED_ADDR
-6183        if !scheduling_info.is_abandoned
-6184            && scheduling_info.may_send_data
-6185            && space_id == SpaceId::Data
-6186            && self
-6187                .config
-6188                .address_discovery_role
-6189                .should_report(&self.peer_params.address_discovery_role)
-6190            && (!path.observed_addr_sent || space.pending.observed_addr)
-6191        {
-6192            let frame =
-6193                frame::ObservedAddr::new(path.network_path.remote, self.next_observed_addr_seq_no);
-6194            if builder.frame_space_remaining() > frame.size() {
-6195                builder.write_frame(frame, stats);
-6196
-6197                self.next_observed_addr_seq_no = self.next_observed_addr_seq_no.saturating_add(1u8);
-6198                path.observed_addr_sent = true;
+5998        // IMMEDIATE_ACK
+5999        if !scheduling_info.is_abandoned
+6000            && mem::replace(&mut space.for_path(path_id).immediate_ack_pending, false)
+6001        {
+6002            debug_assert_eq!(
+6003                space_id,
+6004                SpaceId::Data,
+6005                "immediate acks must be sent in the data space"
+6006            );
+6007            builder.write_frame(frame::ImmediateAck, stats);
+6008        }
+6009
+6010        // ACK
+6011        if !scheduling_info.is_abandoned && scheduling_info.may_send_data {
+6012            for path_id in space
+6013                .number_spaces
+6014                .iter_mut()
+6015                .filter(|(_, pns)| pns.pending_acks.can_send())
+6016                .map(|(&path_id, _)| path_id)
+6017                .collect::<Vec<_>>()
+6018            {
+6019                Self::populate_acks(
+6020                    now,
+6021                    self.receiving_ecn,
+6022                    path_id,
+6023                    space_id,
+6024                    space,
+6025                    is_multipath_negotiated,
+6026                    builder,
+6027                    stats,
+6028                    space_has_keys,
+6029                );
+6030            }
+6031        }
+6032
+6033        // ACK_FREQUENCY
+6034        if !scheduling_info.is_abandoned
+6035            && scheduling_info.may_send_data
+6036            && mem::replace(&mut space.pending.ack_frequency, false)
+6037        {
+6038            let sequence_number = self.ack_frequency.next_sequence_number();
+6039
+6040            // Safe to unwrap because this is always provided when ACK frequency is enabled
+6041            let config = self.config.ack_frequency_config.as_ref().unwrap();
+6042
+6043            // Ensure the delay is within bounds to avoid a PROTOCOL_VIOLATION error
+6044            let max_ack_delay = self.ack_frequency.candidate_max_ack_delay(
+6045                path.rtt.get(),
+6046                config,
+6047                &self.peer_params,
+6048            );
+6049
+6050            let frame = frame::AckFrequency {
+6051                sequence: sequence_number,
+6052                ack_eliciting_threshold: config.ack_eliciting_threshold,
+6053                request_max_ack_delay: max_ack_delay.as_micros().try_into().unwrap_or(VarInt::MAX),
+6054                reordering_threshold: config.reordering_threshold,
+6055            };
+6056            builder.write_frame(frame, stats);
+6057
+6058            self.ack_frequency
+6059                .ack_frequency_sent(path_id, builder.packet_number, max_ack_delay);
+6060        }
+6061
+6062        // PATH_CHALLENGE
+6063        if !scheduling_info.is_abandoned
+6064            && space_id == SpaceId::Data
+6065            && path.pending_on_path_challenge
+6066            && !self.state.is_closed()
+6067            && builder.frame_space_remaining() > frame::PathChallenge::SIZE_BOUND
+6068        // we don't want to send new challenges if we are already closing
+6069        {
+6070            path.pending_on_path_challenge = false;
+6071
+6072            let token = self.rng.random();
+6073            path.record_path_challenge_sent(now, token, path.network_path);
+6074            // Generate a new challenge every time we send a new PATH_CHALLENGE
+6075            let challenge = frame::PathChallenge(token);
+6076            builder.write_frame(challenge, stats);
+6077            builder.require_padding();
+6078            let pto = self.ack_frequency.max_ack_delay_for_pto() + path.rtt.pto_base();
+6079            match path.open_status {
+6080                paths::OpenStatus::Sent | paths::OpenStatus::Informed => {}
+6081                paths::OpenStatus::Pending => {
+6082                    path.open_status = paths::OpenStatus::Sent;
+6083                    self.timers.set(
+6084                        Timer::PerPath(path_id, PathTimer::AbandonFromValidation),
+6085                        now + 3 * pto,
+6086                        self.qlog.with_time(now),
+6087                    );
+6088                }
+6089            }
+6090
+6091            self.timers.set(
+6092                Timer::PerPath(path_id, PathTimer::PathChallengeLost),
+6093                now + pto,
+6094                self.qlog.with_time(now),
+6095            );
+6096
+6097            if is_multipath_negotiated && !path.validated && path.pending_on_path_challenge {
+6098                // queue informing the path status along with the challenge
+6099                space.pending.path_status.insert(path_id);
+6100            }
+6101
+6102            // Always include an OBSERVED_ADDR frame with a PATH_CHALLENGE, regardless
+6103            // of whether one has already been sent on this path.
+6104            if space_id == SpaceId::Data
+6105                && self
+6106                    .config
+6107                    .address_discovery_role
+6108                    .should_report(&self.peer_params.address_discovery_role)
+6109            {
+6110                let frame = frame::ObservedAddr::new(
+6111                    path.network_path.remote,
+6112                    self.next_observed_addr_seq_no,
+6113                );
+6114                if builder.frame_space_remaining() > frame.size() {
+6115                    builder.write_frame(frame, stats);
+6116
+6117                    self.next_observed_addr_seq_no =
+6118                        self.next_observed_addr_seq_no.saturating_add(1u8);
+6119                    path.observed_addr_sent = true;
+6120
+6121                    space.pending.observed_addr = false;
+6122                }
+6123            }
+6124        }
+6125
+6126        // PATH_RESPONSE
+6127        if !scheduling_info.is_abandoned
+6128            && space_id == SpaceId::Data
+6129            && builder.frame_space_remaining() > frame::PathResponse::SIZE_BOUND
+6130            && let Some(token) = path.path_responses.pop_on_path(path.network_path)
+6131        {
+6132            let response = frame::PathResponse(token);
+6133            builder.write_frame(response, stats);
+6134            builder.require_padding();
+6135
+6136            // NOTE: this is technically not required but might be useful to ride the
+6137            // request/response nature of path challenges to refresh an observation
+6138            // Since PATH_RESPONSE is a probing frame, this is allowed by the spec.
+6139            if space_id == SpaceId::Data
+6140                && self
+6141                    .config
+6142                    .address_discovery_role
+6143                    .should_report(&self.peer_params.address_discovery_role)
+6144            {
+6145                let frame = frame::ObservedAddr::new(
+6146                    path.network_path.remote,
+6147                    self.next_observed_addr_seq_no,
+6148                );
+6149                if builder.frame_space_remaining() > frame.size() {
+6150                    builder.write_frame(frame, stats);
+6151
+6152                    self.next_observed_addr_seq_no =
+6153                        self.next_observed_addr_seq_no.saturating_add(1u8);
+6154                    path.observed_addr_sent = true;
+6155
+6156                    space.pending.observed_addr = false;
+6157                }
+6158            }
+6159        }
+6160
+6161        // REACH_OUT
+6162        while !scheduling_info.is_abandoned
+6163            && scheduling_info.may_send_data
+6164            && let Some(reach_out) = space
+6165                .pending
+6166                .reach_out
+6167                .pop_if(|frame| builder.frame_space_remaining() >= frame.size())
+6168        {
+6169            builder.write_frame(reach_out, stats);
+6170        }
+6171
+6172        // PATH_ABANDON
+6173        if space_id == SpaceId::Data
+6174            && scheduling_info.is_abandoned
+6175            && scheduling_info.may_self_abandon
+6176            && frame::PathAbandon::SIZE_BOUND <= builder.frame_space_remaining()
+6177            && let Some(error_code) = space.pending.path_abandon.remove(&path_id)
+6178        {
+6179            let frame = frame::PathAbandon {
+6180                path_id,
+6181                error_code,
+6182            };
+6183            builder.write_frame(frame, stats);
+6184
+6185            // Consider remotely issued CIDs as retired now that we have sent this frame at
+6186            // least once.
+6187            self.remote_cids.remove(&path_id);
+6188        }
+6189        while space_id == SpaceId::Data
+6190            && scheduling_info.may_send_data
+6191            && frame::PathAbandon::SIZE_BOUND <= builder.frame_space_remaining()
+6192            && let Some((abandoned_path_id, error_code)) = space.pending.path_abandon.pop_first()
+6193        {
+6194            let frame = frame::PathAbandon {
+6195                path_id: abandoned_path_id,
+6196                error_code,
+6197            };
+6198            builder.write_frame(frame, stats);
 6199
-6200                space.pending.observed_addr = false;
-6201            }
-6202        }
-6203
-6204        // CRYPTO
-6205        while !is_0rtt
-6206            && !scheduling_info.is_abandoned
+6200            // Consider remotely issued CIDs as retired now that we have sent this frame at
+6201            // least once.
+6202            self.remote_cids.remove(&abandoned_path_id);
+6203        }
+6204
+6205        // OBSERVED_ADDR
+6206        if !scheduling_info.is_abandoned
 6207            && scheduling_info.may_send_data
-6208            && builder.frame_space_remaining() > frame::Crypto::SIZE_BOUND
-6209        {
-6210            let Some(mut frame) = space.pending.crypto.pop_front() else {
-6211                break;
-6212            };
-6213
-6214            // Calculate the maximum amount of crypto data we can store in the buffer.
-6215            // Since the offset is known, we can reserve the exact size required to encode it.
-6216            // For length we reserve 2bytes which allows to encode up to 2^14,
-6217            // which is more than what fits into normally sized QUIC frames.
-6218            let max_crypto_data_size = builder.frame_space_remaining()
-6219                - 1 // Frame Type
-6220                - VarInt::size(unsafe { VarInt::from_u64_unchecked(frame.offset) })
-6221                - 2; // Maximum encoded length for frame size, given we send less than 2^14 bytes
+6208            && space_id == SpaceId::Data
+6209            && self
+6210                .config
+6211                .address_discovery_role
+6212                .should_report(&self.peer_params.address_discovery_role)
+6213            && (!path.observed_addr_sent || space.pending.observed_addr)
+6214        {
+6215            let frame =
+6216                frame::ObservedAddr::new(path.network_path.remote, self.next_observed_addr_seq_no);
+6217            if builder.frame_space_remaining() > frame.size() {
+6218                builder.write_frame(frame, stats);
+6219
+6220                self.next_observed_addr_seq_no = self.next_observed_addr_seq_no.saturating_add(1u8);
+6221                path.observed_addr_sent = true;
 6222
-6223            let len = frame
-6224                .data
-6225                .len()
-6226                .min(2usize.pow(14) - 1)
-6227                .min(max_crypto_data_size);
-6228
-6229            let data = frame.data.split_to(len);
-6230            let offset = frame.offset;
-6231            let truncated = frame::Crypto { offset, data };
-6232            builder.write_frame(truncated, stats);
-6233
-6234            if !frame.data.is_empty() {
-6235                frame.offset += len as u64;
-6236                space.pending.crypto.push_front(frame);
-6237            }
-6238        }
-6239
-6240        // PATH_STATUS_AVAILABLE & PATH_STATUS_BACKUP
-6241        while space_id == SpaceId::Data
-6242            && !scheduling_info.is_abandoned
-6243            && scheduling_info.may_send_data
-6244            && frame::PathStatusAvailable::SIZE_BOUND <= builder.frame_space_remaining()
-6245        {
-6246            let Some(path_id) = space.pending.path_status.pop_first() else {
-6247                break;
-6248            };
-6249            let Some(path) = self.paths.get(&path_id).map(|path_state| &path_state.data) else {
-6250                trace!(%path_id, "discarding queued path status for unknown path");
-6251                continue;
-6252            };
-6253
-6254            let seq = path.status.seq();
-6255            match path.local_status() {
-6256                PathStatus::Available => {
-6257                    let frame = frame::PathStatusAvailable {
-6258                        path_id,
-6259                        status_seq_no: seq,
-6260                    };
-6261                    builder.write_frame(frame, stats);
-6262                }
-6263                PathStatus::Backup => {
-6264                    let frame = frame::PathStatusBackup {
-6265                        path_id,
-6266                        status_seq_no: seq,
-6267                    };
-6268                    builder.write_frame(frame, stats);
-6269                }
-6270            }
-6271        }
-6272
-6273        // MAX_PATH_ID
-6274        if space_id == SpaceId::Data
-6275            && !scheduling_info.is_abandoned
-6276            && scheduling_info.may_send_data
-6277            && space.pending.max_path_id
-6278            && frame::MaxPathId::SIZE_BOUND <= builder.frame_space_remaining()
-6279        {
-6280            let frame = frame::MaxPathId(self.local_max_path_id);
-6281            builder.write_frame(frame, stats);
-6282            space.pending.max_path_id = false;
-6283        }
-6284
-6285        // PATHS_BLOCKED
-6286        if space_id == SpaceId::Data
-6287            && !scheduling_info.is_abandoned
-6288            && scheduling_info.may_send_data
-6289            && space.pending.paths_blocked
-6290            && frame::PathsBlocked::SIZE_BOUND <= builder.frame_space_remaining()
-6291        {
-6292            let frame = frame::PathsBlocked(self.remote_max_path_id);
-6293            builder.write_frame(frame, stats);
-6294            space.pending.paths_blocked = false;
-6295        }
-6296
-6297        // PATH_CIDS_BLOCKED
-6298        while space_id == SpaceId::Data
-6299            && !scheduling_info.is_abandoned
-6300            && scheduling_info.may_send_data
-6301            && frame::PathCidsBlocked::SIZE_BOUND <= builder.frame_space_remaining()
+6223                space.pending.observed_addr = false;
+6224            }
+6225        }
+6226
+6227        // CRYPTO
+6228        while !is_0rtt
+6229            && !scheduling_info.is_abandoned
+6230            && scheduling_info.may_send_data
+6231            && builder.frame_space_remaining() > frame::Crypto::SIZE_BOUND
+6232        {
+6233            let Some(mut frame) = space.pending.crypto.pop_front() else {
+6234                break;
+6235            };
+6236
+6237            // Calculate the maximum amount of crypto data we can store in the buffer.
+6238            // Since the offset is known, we can reserve the exact size required to encode it.
+6239            // For length we reserve 2bytes which allows to encode up to 2^14,
+6240            // which is more than what fits into normally sized QUIC frames.
+6241            let max_crypto_data_size = builder.frame_space_remaining()
+6242                - 1 // Frame Type
+6243                - VarInt::size(unsafe { VarInt::from_u64_unchecked(frame.offset) })
+6244                - 2; // Maximum encoded length for frame size, given we send less than 2^14 bytes
+6245
+6246            let len = frame
+6247                .data
+6248                .len()
+6249                .min(2usize.pow(14) - 1)
+6250                .min(max_crypto_data_size);
+6251
+6252            let data = frame.data.split_to(len);
+6253            let offset = frame.offset;
+6254            let truncated = frame::Crypto { offset, data };
+6255            builder.write_frame(truncated, stats);
+6256
+6257            if !frame.data.is_empty() {
+6258                frame.offset += len as u64;
+6259                space.pending.crypto.push_front(frame);
+6260            }
+6261        }
+6262
+6263        // PATH_STATUS_AVAILABLE & PATH_STATUS_BACKUP
+6264        while space_id == SpaceId::Data
+6265            && !scheduling_info.is_abandoned
+6266            && scheduling_info.may_send_data
+6267            && frame::PathStatusAvailable::SIZE_BOUND <= builder.frame_space_remaining()
+6268        {
+6269            let Some(path_id) = space.pending.path_status.pop_first() else {
+6270                break;
+6271            };
+6272            let Some(path) = self.paths.get(&path_id).map(|path_state| &path_state.data) else {
+6273                trace!(%path_id, "discarding queued path status for unknown path");
+6274                continue;
+6275            };
+6276
+6277            let seq = path.status.seq();
+6278            match path.local_status() {
+6279                PathStatus::Available => {
+6280                    let frame = frame::PathStatusAvailable {
+6281                        path_id,
+6282                        status_seq_no: seq,
+6283                    };
+6284                    builder.write_frame(frame, stats);
+6285                }
+6286                PathStatus::Backup => {
+6287                    let frame = frame::PathStatusBackup {
+6288                        path_id,
+6289                        status_seq_no: seq,
+6290                    };
+6291                    builder.write_frame(frame, stats);
+6292                }
+6293            }
+6294        }
+6295
+6296        // MAX_PATH_ID
+6297        if space_id == SpaceId::Data
+6298            && !scheduling_info.is_abandoned
+6299            && scheduling_info.may_send_data
+6300            && space.pending.max_path_id
+6301            && frame::MaxPathId::SIZE_BOUND <= builder.frame_space_remaining()
 6302        {
-6303            let Some(path_id) = space.pending.path_cids_blocked.pop_first() else {
-6304                break;
-6305            };
-6306            let next_seq = match self.remote_cids.get(&path_id) {
-6307                Some(cid_queue) => VarInt(cid_queue.active_seq() + 1),
-6308                None => VarInt(0),
-6309            };
-6310            let frame = frame::PathCidsBlocked { path_id, next_seq };
-6311            builder.write_frame(frame, stats);
-6312        }
-6313
-6314        // RESET_STREAM, STOP_SENDING, MAX_DATA, MAX_STREAM_DATA, MAX_STREAMS
-6315        if space_id == SpaceId::Data
-6316            && !scheduling_info.is_abandoned
-6317            && scheduling_info.may_send_data
-6318        {
-6319            self.streams
-6320                .write_control_frames(builder, &mut space.pending, stats);
-6321        }
-6322
-6323        // NEW_CONNECTION_ID
-6324        let cid_len = self
-6325            .local_cid_state
-6326            .values()
-6327            .map(|cid_state| cid_state.cid_len())
-6328            .max()
-6329            .expect("some local CID state must exist");
-6330        let new_cid_size_bound =
-6331            frame::NewConnectionId::size_bound(is_multipath_negotiated, cid_len);
-6332        while !scheduling_info.is_abandoned
-6333            && scheduling_info.may_send_data
-6334            && builder.frame_space_remaining() > new_cid_size_bound
-6335        {
-6336            let Some(issued) = space.pending.new_cids.pop() else {
-6337                break;
-6338            };
-6339            let retire_prior_to = self
-6340                .local_cid_state
-6341                .get(&issued.path_id)
-6342                .map(|cid_state| cid_state.retire_prior_to())
-6343                .unwrap_or_else(|| panic!("missing local CID state for path={}", issued.path_id));
-6344
-6345            let cid_path_id = match is_multipath_negotiated {
-6346                true => Some(issued.path_id),
-6347                false => {
-6348                    debug_assert_eq!(issued.path_id, PathId::ZERO);
-6349                    None
-6350                }
-6351            };
-6352            let frame = frame::NewConnectionId {
-6353                path_id: cid_path_id,
-6354                sequence: issued.sequence,
-6355                retire_prior_to,
-6356                id: issued.id,
-6357                reset_token: issued.reset_token,
-6358            };
-6359            builder.write_frame(frame, stats);
-6360        }
-6361
-6362        // RETIRE_CONNECTION_ID
-6363        let retire_cid_bound = frame::RetireConnectionId::size_bound(is_multipath_negotiated);
-6364        while !scheduling_info.is_abandoned
-6365            && scheduling_info.may_send_data
-6366            && builder.frame_space_remaining() > retire_cid_bound
-6367        {
-6368            let (path_id, sequence) = match space.pending.retire_cids.pop() {
-6369                Some((PathId::ZERO, seq)) if !is_multipath_negotiated => (None, seq),
-6370                Some((path_id, seq)) => (Some(path_id), seq),
-6371                None => break,
-6372            };
-6373            let frame = frame::RetireConnectionId { path_id, sequence };
-6374            builder.write_frame(frame, stats);
-6375        }
-6376
-6377        // DATAGRAM
-6378        let mut sent_datagrams = false;
-6379        while !scheduling_info.is_abandoned
-6380            && scheduling_info.may_send_data
-6381            && builder.frame_space_remaining() > Datagram::SIZE_BOUND
-6382            && space_id == SpaceId::Data
-6383        {
-6384            match self.datagrams.write(builder, stats) {
-6385                true => {
-6386                    sent_datagrams = true;
-6387                }
-6388                false => break,
-6389            }
-6390        }
-6391        if self.datagrams.send_blocked && sent_datagrams {
-6392            self.events.push_back(Event::DatagramsUnblocked);
-6393            self.datagrams.send_blocked = false;
-6394        }
-6395
-6396        let path = &mut self.paths.get_mut(&path_id).expect("known path").data;
-6397
-6398        // NEW_TOKEN
-6399        if !scheduling_info.is_abandoned && scheduling_info.may_send_data {
-6400            while let Some(network_path) = space.pending.new_tokens.pop() {
-6401                debug_assert_eq!(space_id, SpaceId::Data);
-6402                let ConnectionSide::Server { server_config } = &self.side else {
-6403                    panic!("NEW_TOKEN frames should not be enqueued by clients");
-6404                };
-6405
-6406                if !network_path.is_probably_same_path(&path.network_path) {
-6407                    // NEW_TOKEN frames contain tokens bound to a client's IP address, and are only
-6408                    // useful if used from the same IP address.  Thus, we abandon enqueued NEW_TOKEN
-6409                    // frames upon an path change. Instead, when the new path becomes validated,
-6410                    // NEW_TOKEN frames may be enqueued for the new path instead.
-6411                    continue;
-6412                }
-6413
-6414                let token = Token::new(
-6415                    TokenPayload::Validation {
-6416                        ip: network_path.remote.ip(),
-6417                        issued: server_config.time_source.now(),
-6418                    },
-6419                    &mut self.rng,
-6420                );
-6421                let new_token = NewToken {
-6422                    token: token.encode(&*server_config.token_key).into(),
-6423                };
-6424
-6425                if builder.frame_space_remaining() < new_token.size() {
-6426                    space.pending.new_tokens.push(network_path);
-6427                    break;
-6428                }
-6429
-6430                builder.write_frame(new_token, stats);
-6431                builder.retransmits_mut().new_tokens.push(network_path);
-6432            }
-6433        }
-6434
-6435        // ADD_ADDRESS
-6436        while space_id == SpaceId::Data
-6437            && !scheduling_info.is_abandoned
-6438            && scheduling_info.may_send_data
-6439            && frame::AddAddress::SIZE_BOUND <= builder.frame_space_remaining()
-6440        {
-6441            if let Some(added_address) = space.pending.add_address.pop_last() {
-6442                builder.write_frame(added_address, stats);
-6443            } else {
-6444                break;
-6445            }
-6446        }
+6303            let frame = frame::MaxPathId(self.local_max_path_id);
+6304            builder.write_frame(frame, stats);
+6305            space.pending.max_path_id = false;
+6306        }
+6307
+6308        // PATHS_BLOCKED
+6309        if space_id == SpaceId::Data
+6310            && !scheduling_info.is_abandoned
+6311            && scheduling_info.may_send_data
+6312            && space.pending.paths_blocked
+6313            && frame::PathsBlocked::SIZE_BOUND <= builder.frame_space_remaining()
+6314        {
+6315            let frame = frame::PathsBlocked(self.remote_max_path_id);
+6316            builder.write_frame(frame, stats);
+6317            space.pending.paths_blocked = false;
+6318        }
+6319
+6320        // PATH_CIDS_BLOCKED
+6321        while space_id == SpaceId::Data
+6322            && !scheduling_info.is_abandoned
+6323            && scheduling_info.may_send_data
+6324            && frame::PathCidsBlocked::SIZE_BOUND <= builder.frame_space_remaining()
+6325        {
+6326            let Some(path_id) = space.pending.path_cids_blocked.pop_first() else {
+6327                break;
+6328            };
+6329            let next_seq = match self.remote_cids.get(&path_id) {
+6330                Some(cid_queue) => VarInt(cid_queue.active_seq() + 1),
+6331                None => VarInt(0),
+6332            };
+6333            let frame = frame::PathCidsBlocked { path_id, next_seq };
+6334            builder.write_frame(frame, stats);
+6335        }
+6336
+6337        // RESET_STREAM, STOP_SENDING, MAX_DATA, MAX_STREAM_DATA, MAX_STREAMS
+6338        if space_id == SpaceId::Data
+6339            && !scheduling_info.is_abandoned
+6340            && scheduling_info.may_send_data
+6341        {
+6342            self.streams
+6343                .write_control_frames(builder, &mut space.pending, stats);
+6344        }
+6345
+6346        // NEW_CONNECTION_ID
+6347        let cid_len = self
+6348            .local_cid_state
+6349            .values()
+6350            .map(|cid_state| cid_state.cid_len())
+6351            .max()
+6352            .expect("some local CID state must exist");
+6353        let new_cid_size_bound =
+6354            frame::NewConnectionId::size_bound(is_multipath_negotiated, cid_len);
+6355        while !scheduling_info.is_abandoned
+6356            && scheduling_info.may_send_data
+6357            && builder.frame_space_remaining() > new_cid_size_bound
+6358        {
+6359            let Some(issued) = space.pending.new_cids.pop() else {
+6360                break;
+6361            };
+6362            let retire_prior_to = self
+6363                .local_cid_state
+6364                .get(&issued.path_id)
+6365                .map(|cid_state| cid_state.retire_prior_to())
+6366                .unwrap_or_else(|| panic!("missing local CID state for path={}", issued.path_id));
+6367
+6368            let cid_path_id = match is_multipath_negotiated {
+6369                true => Some(issued.path_id),
+6370                false => {
+6371                    debug_assert_eq!(issued.path_id, PathId::ZERO);
+6372                    None
+6373                }
+6374            };
+6375            let frame = frame::NewConnectionId {
+6376                path_id: cid_path_id,
+6377                sequence: issued.sequence,
+6378                retire_prior_to,
+6379                id: issued.id,
+6380                reset_token: issued.reset_token,
+6381            };
+6382            builder.write_frame(frame, stats);
+6383        }
+6384
+6385        // RETIRE_CONNECTION_ID
+6386        let retire_cid_bound = frame::RetireConnectionId::size_bound(is_multipath_negotiated);
+6387        while !scheduling_info.is_abandoned
+6388            && scheduling_info.may_send_data
+6389            && builder.frame_space_remaining() > retire_cid_bound
+6390        {
+6391            let (path_id, sequence) = match space.pending.retire_cids.pop() {
+6392                Some((PathId::ZERO, seq)) if !is_multipath_negotiated => (None, seq),
+6393                Some((path_id, seq)) => (Some(path_id), seq),
+6394                None => break,
+6395            };
+6396            let frame = frame::RetireConnectionId { path_id, sequence };
+6397            builder.write_frame(frame, stats);
+6398        }
+6399
+6400        // DATAGRAM
+6401        let mut sent_datagrams = false;
+6402        while !scheduling_info.is_abandoned
+6403            && scheduling_info.may_send_data
+6404            && builder.frame_space_remaining() > Datagram::SIZE_BOUND
+6405            && space_id == SpaceId::Data
+6406        {
+6407            match self.datagrams.write(builder, stats) {
+6408                true => {
+6409                    sent_datagrams = true;
+6410                }
+6411                false => break,
+6412            }
+6413        }
+6414        if self.datagrams.send_blocked && sent_datagrams {
+6415            self.events.push_back(Event::DatagramsUnblocked);
+6416            self.datagrams.send_blocked = false;
+6417        }
+6418
+6419        let path = &mut self.paths.get_mut(&path_id).expect("known path").data;
+6420
+6421        // NEW_TOKEN
+6422        if !scheduling_info.is_abandoned && scheduling_info.may_send_data {
+6423            while let Some(network_path) = space.pending.new_tokens.pop() {
+6424                debug_assert_eq!(space_id, SpaceId::Data);
+6425                let ConnectionSide::Server { server_config } = &self.side else {
+6426                    panic!("NEW_TOKEN frames should not be enqueued by clients");
+6427                };
+6428
+6429                if !network_path.is_probably_same_path(&path.network_path) {
+6430                    // NEW_TOKEN frames contain tokens bound to a client's IP address, and are only
+6431                    // useful if used from the same IP address.  Thus, we abandon enqueued NEW_TOKEN
+6432                    // frames upon an path change. Instead, when the new path becomes validated,
+6433                    // NEW_TOKEN frames may be enqueued for the new path instead.
+6434                    continue;
+6435                }
+6436
+6437                let token = Token::new(
+6438                    TokenPayload::Validation {
+6439                        ip: network_path.remote.ip(),
+6440                        issued: server_config.time_source.now(),
+6441                    },
+6442                    &mut self.rng,
+6443                );
+6444                let new_token = NewToken {
+6445                    token: token.encode(&*server_config.token_key).into(),
+6446                };
 6447
-6448        // REMOVE_ADDRESS
-6449        while space_id == SpaceId::Data
-6450            && !scheduling_info.is_abandoned
-6451            && scheduling_info.may_send_data
-6452            && frame::RemoveAddress::SIZE_BOUND <= builder.frame_space_remaining()
-6453        {
-6454            if let Some(removed_address) = space.pending.remove_address.pop_last() {
-6455                builder.write_frame(removed_address, stats);
-6456            } else {
-6457                break;
-6458            }
-6459        }
-6460
-6461        // STREAM
-6462        if !scheduling_info.is_abandoned
-6463            && scheduling_info.may_send_data
-6464            && space_id == SpaceId::Data
-6465        {
-6466            self.streams
-6467                .write_stream_frames(builder, self.config.send_fairness, stats);
-6468        }
-6469    }
+6448                if builder.frame_space_remaining() < new_token.size() {
+6449                    space.pending.new_tokens.push(network_path);
+6450                    break;
+6451                }
+6452
+6453                builder.write_frame(new_token, stats);
+6454                builder.retransmits_mut().new_tokens.push(network_path);
+6455            }
+6456        }
+6457
+6458        // ADD_ADDRESS
+6459        while space_id == SpaceId::Data
+6460            && !scheduling_info.is_abandoned
+6461            && scheduling_info.may_send_data
+6462            && frame::AddAddress::SIZE_BOUND <= builder.frame_space_remaining()
+6463        {
+6464            if let Some(added_address) = space.pending.add_address.pop_last() {
+6465                builder.write_frame(added_address, stats);
+6466            } else {
+6467                break;
+6468            }
+6469        }
 6470
-6471    /// Write pending ACKs into a buffer
-6472    fn populate_acks<'a, 'b>(
-6473        now: Instant,
-6474        receiving_ecn: bool,
-6475        path_id: PathId,
-6476        space_id: SpaceId,
-6477        space: &mut PacketSpace,
-6478        is_multipath_negotiated: bool,
-6479        builder: &mut PacketBuilder<'a, 'b>,
-6480        stats: &mut FrameStats,
-6481        space_has_keys: bool,
-6482    ) {
-6483        // 0-RTT packets must never carry acks (which would have to be of handshake packets)
-6484        debug_assert!(space_has_keys, "tried to send ACK in 0-RTT");
-6485
-6486        debug_assert!(
-6487            is_multipath_negotiated || path_id == PathId::ZERO,
-6488            "Only PathId::ZERO allowed without multipath (have {path_id:?})"
-6489        );
-6490        if is_multipath_negotiated {
-6491            debug_assert!(
-6492                space_id == SpaceId::Data || path_id == PathId::ZERO,
-6493                "path acks must be sent in 1RTT space (have {space_id:?})"
-6494            );
-6495        }
-6496
-6497        let pns = space.for_path(path_id);
-6498        let ranges = pns.pending_acks.ranges();
-6499        debug_assert!(!ranges.is_empty(), "can not send empty ACK range");
-6500        let ecn = if receiving_ecn {
-6501            Some(&pns.ecn_counters)
-6502        } else {
-6503            None
-6504        };
-6505
-6506        let delay_micros = pns.pending_acks.ack_delay(now).as_micros() as u64;
-6507        // TODO: This should come from `TransportConfig` if that gets configurable.
-6508        let ack_delay_exp = TransportParameters::default().ack_delay_exponent;
-6509        let delay = delay_micros >> ack_delay_exp.into_inner();
-6510
-6511        if is_multipath_negotiated && space_id == SpaceId::Data {
-6512            if !ranges.is_empty() {
-6513                let frame = frame::PathAck::encoder(path_id, delay, ranges, ecn);
-6514                builder.write_frame(frame, stats);
-6515            }
-6516        } else {
-6517            builder.write_frame(frame::Ack::encoder(delay, ranges, ecn), stats);
+6471        // REMOVE_ADDRESS
+6472        while space_id == SpaceId::Data
+6473            && !scheduling_info.is_abandoned
+6474            && scheduling_info.may_send_data
+6475            && frame::RemoveAddress::SIZE_BOUND <= builder.frame_space_remaining()
+6476        {
+6477            if let Some(removed_address) = space.pending.remove_address.pop_last() {
+6478                builder.write_frame(removed_address, stats);
+6479            } else {
+6480                break;
+6481            }
+6482        }
+6483
+6484        // STREAM
+6485        if !scheduling_info.is_abandoned
+6486            && scheduling_info.may_send_data
+6487            && space_id == SpaceId::Data
+6488        {
+6489            self.streams
+6490                .write_stream_frames(builder, self.config.send_fairness, stats);
+6491        }
+6492    }
+6493
+6494    /// Write pending ACKs into a buffer
+6495    fn populate_acks<'a, 'b>(
+6496        now: Instant,
+6497        receiving_ecn: bool,
+6498        path_id: PathId,
+6499        space_id: SpaceId,
+6500        space: &mut PacketSpace,
+6501        is_multipath_negotiated: bool,
+6502        builder: &mut PacketBuilder<'a, 'b>,
+6503        stats: &mut FrameStats,
+6504        space_has_keys: bool,
+6505    ) {
+6506        // 0-RTT packets must never carry acks (which would have to be of handshake packets)
+6507        debug_assert!(space_has_keys, "tried to send ACK in 0-RTT");
+6508
+6509        debug_assert!(
+6510            is_multipath_negotiated || path_id == PathId::ZERO,
+6511            "Only PathId::ZERO allowed without multipath (have {path_id:?})"
+6512        );
+6513        if is_multipath_negotiated {
+6514            debug_assert!(
+6515                space_id == SpaceId::Data || path_id == PathId::ZERO,
+6516                "path acks must be sent in 1RTT space (have {space_id:?})"
+6517            );
 6518        }
-6519    }
-6520
-6521    fn close_common(&mut self) {
-6522        trace!("connection closed");
-6523        self.timers.reset();
-6524    }
-6525
-6526    fn set_close_timer(&mut self, now: Instant) {
-6527        // QUIC-MULTIPATH § 2.6 Connection Closure: draining for 3*PTO using the max PTO of
-6528        // all paths.
-6529        let pto_max = self.max_pto_for_space(self.highest_space);
-6530        self.timers.set(
-6531            Timer::Conn(ConnTimer::Close),
-6532            now + 3 * pto_max,
-6533            self.qlog.with_time(now),
-6534        );
-6535    }
-6536
-6537    /// Handle transport parameters received from the peer
-6538    ///
-6539    /// *remote_cid* and *local_cid* are the source and destination CIDs respectively of the
-6540    /// *packet into which the transport parameters arrived.
-6541    fn handle_peer_params(
-6542        &mut self,
-6543        params: TransportParameters,
-6544        local_cid: ConnectionId,
-6545        remote_cid: ConnectionId,
-6546        now: Instant,
-6547    ) -> Result<(), TransportError> {
-6548        if Some(self.original_remote_cid) != params.initial_src_cid
-6549            || (self.side.is_client()
-6550                && (Some(self.initial_dst_cid) != params.original_dst_cid
-6551                    || self.retry_src_cid != params.retry_src_cid))
-6552        {
-6553            return Err(TransportError::TRANSPORT_PARAMETER_ERROR(
-6554                "CID authentication failure",
-6555            ));
-6556        }
-6557        if params.initial_max_path_id.is_some() && (local_cid.is_empty() || remote_cid.is_empty()) {
-6558            return Err(TransportError::PROTOCOL_VIOLATION(
-6559                "multipath must not use zero-length CIDs",
-6560            ));
-6561        }
-6562
-6563        self.set_peer_params(params);
-6564        self.qlog.emit_peer_transport_params_received(self, now);
-6565
-6566        Ok(())
-6567    }
-6568
-6569    fn set_peer_params(&mut self, params: TransportParameters) {
-6570        self.streams.set_params(&params);
-6571        self.idle_timeout =
-6572            negotiate_max_idle_timeout(self.config.max_idle_timeout, Some(params.max_idle_timeout));
-6573        trace!("negotiated max idle timeout {:?}", self.idle_timeout);
-6574
-6575        if let Some(ref info) = params.preferred_address {
-6576            // During the handshake PathId::ZERO exists.
-6577            self.remote_cids.get_mut(&PathId::ZERO).expect("not yet abandoned").insert(frame::NewConnectionId {
-6578                path_id: None,
-6579                sequence: 1,
-6580                id: info.connection_id,
-6581                reset_token: info.stateless_reset_token,
-6582                retire_prior_to: 0,
-6583            })
-6584            .expect(
-6585                "preferred address CID is the first received, and hence is guaranteed to be legal",
-6586            );
-6587            let remote = self.path_data(PathId::ZERO).network_path.remote;
-6588            self.set_reset_token(PathId::ZERO, remote, info.stateless_reset_token);
-6589        }
-6590        self.ack_frequency.peer_max_ack_delay = get_max_ack_delay(&params);
+6519
+6520        let pns = space.for_path(path_id);
+6521        let ranges = pns.pending_acks.ranges();
+6522        debug_assert!(!ranges.is_empty(), "can not send empty ACK range");
+6523        let ecn = if receiving_ecn {
+6524            Some(&pns.ecn_counters)
+6525        } else {
+6526            None
+6527        };
+6528
+6529        let delay_micros = pns.pending_acks.ack_delay(now).as_micros() as u64;
+6530        // TODO: This should come from `TransportConfig` if that gets configurable.
+6531        let ack_delay_exp = TransportParameters::default().ack_delay_exponent;
+6532        let delay = delay_micros >> ack_delay_exp.into_inner();
+6533
+6534        if is_multipath_negotiated && space_id == SpaceId::Data {
+6535            if !ranges.is_empty() {
+6536                let frame = frame::PathAck::encoder(path_id, delay, ranges, ecn);
+6537                builder.write_frame(frame, stats);
+6538            }
+6539        } else {
+6540            builder.write_frame(frame::Ack::encoder(delay, ranges, ecn), stats);
+6541        }
+6542    }
+6543
+6544    fn close_common(&mut self) {
+6545        trace!("connection closed");
+6546        self.timers.reset();
+6547    }
+6548
+6549    fn set_close_timer(&mut self, now: Instant) {
+6550        // QUIC-MULTIPATH § 2.6 Connection Closure: draining for 3*PTO using the max PTO of
+6551        // all paths.
+6552        let pto_max = self.max_pto_for_space(self.highest_space);
+6553        self.timers.set(
+6554            Timer::Conn(ConnTimer::Close),
+6555            now + 3 * pto_max,
+6556            self.qlog.with_time(now),
+6557        );
+6558    }
+6559
+6560    /// Handle transport parameters received from the peer
+6561    ///
+6562    /// *remote_cid* and *local_cid* are the source and destination CIDs respectively of the
+6563    /// *packet into which the transport parameters arrived.
+6564    fn handle_peer_params(
+6565        &mut self,
+6566        params: TransportParameters,
+6567        local_cid: ConnectionId,
+6568        remote_cid: ConnectionId,
+6569        now: Instant,
+6570    ) -> Result<(), TransportError> {
+6571        if Some(self.original_remote_cid) != params.initial_src_cid
+6572            || (self.side.is_client()
+6573                && (Some(self.initial_dst_cid) != params.original_dst_cid
+6574                    || self.retry_src_cid != params.retry_src_cid))
+6575        {
+6576            return Err(TransportError::TRANSPORT_PARAMETER_ERROR(
+6577                "CID authentication failure",
+6578            ));
+6579        }
+6580        if params.initial_max_path_id.is_some() && (local_cid.is_empty() || remote_cid.is_empty()) {
+6581            return Err(TransportError::PROTOCOL_VIOLATION(
+6582                "multipath must not use zero-length CIDs",
+6583            ));
+6584        }
+6585
+6586        self.set_peer_params(params);
+6587        self.qlog.emit_peer_transport_params_received(self, now);
+6588
+6589        Ok(())
+6590    }
 6591
-6592        let mut multipath_enabled = None;
-6593        if let (Some(local_max_path_id), Some(remote_max_path_id)) = (
-6594            self.config.get_initial_max_path_id(),
-6595            params.initial_max_path_id,
-6596        ) {
-6597            // multipath is enabled, register the local and remote maximums
-6598            self.local_max_path_id = local_max_path_id;
-6599            self.remote_max_path_id = remote_max_path_id;
-6600            let initial_max_path_id = local_max_path_id.min(remote_max_path_id);
-6601            debug!(%initial_max_path_id, "multipath negotiated");
-6602            multipath_enabled = Some(initial_max_path_id);
-6603        }
-6604
-6605        if let Some((max_locally_allowed_remote_addresses, max_remotely_allowed_remote_addresses)) =
-6606            self.config
-6607                .max_remote_nat_traversal_addresses
-6608                .zip(params.max_remote_nat_traversal_addresses)
-6609        {
-6610            if let Some(max_initial_paths) =
-6611                multipath_enabled.map(|path_id| path_id.saturating_add(1u8))
-6612            {
-6613                let max_local_addresses = max_remotely_allowed_remote_addresses.get();
-6614                let max_remote_addresses = max_locally_allowed_remote_addresses.get();
-6615                self.n0_nat_traversal = n0_nat_traversal::State::new(
-6616                    max_remote_addresses,
-6617                    max_local_addresses,
-6618                    self.side(),
-6619                );
-6620                debug!(
-6621                    %max_remote_addresses, %max_local_addresses,
-6622                    "n0's nat traversal negotiated"
-6623                );
-6624
-6625                match self.side() {
-6626                    Side::Client => {
-6627                        if max_initial_paths.as_u32() < max_remote_addresses as u32 + 1 {
-6628                            // in this case the client might try to open `max_remote_addresses` new
-6629                            // paths, but the current multipath configuration will not allow it
-6630                            debug!(%max_initial_paths, %max_remote_addresses, "local client configuration might cause nat traversal issues")
-6631                        } else if max_local_addresses as u64
-6632                            > params.active_connection_id_limit.into_inner()
-6633                        {
-6634                            // the server allows us to send at most `params.active_connection_id_limit`
-6635                            // but they might need at least `max_local_addresses` to effectively send
-6636                            // `PATH_CHALLENGE` frames to each advertised local address
-6637                            debug!(%max_local_addresses, remote_cid_limit=%params.active_connection_id_limit.into_inner(), "remote server configuration might cause nat traversal issues")
-6638                        }
-6639                    }
-6640                    Side::Server => {
-6641                        if (max_initial_paths.as_u32() as u64) < crate::LOCAL_CID_COUNT {
-6642                            debug!(%max_initial_paths, local_cid_limit=%crate::LOCAL_CID_COUNT, "local server configuration might cause nat traversal issues")
-6643                        }
-6644                    }
-6645                }
-6646            } else {
-6647                debug!("n0 nat traversal enabled for both endpoints, but multipath is missing")
-6648            }
-6649        }
-6650
-6651        self.peer_params = params;
-6652        let peer_max_udp_payload_size =
-6653            u16::try_from(self.peer_params.max_udp_payload_size.into_inner()).unwrap_or(u16::MAX);
-6654        self.path_data_mut(PathId::ZERO)
-6655            .mtud
-6656            .on_peer_max_udp_payload_size_received(peer_max_udp_payload_size);
-6657    }
-6658
-6659    /// Decrypts a packet, returning the packet number on success
-6660    fn decrypt_packet(
-6661        &mut self,
-6662        now: Instant,
-6663        path_id: PathId,
-6664        packet: &mut Packet,
-6665    ) -> Result<Option<u64>, Option<TransportError>> {
-6666        let result = self
-6667            .crypto_state
-6668            .decrypt_packet_body(packet, path_id, &self.spaces)?;
-6669
-6670        let Some(result) = result else {
-6671            return Ok(None);
-6672        };
+6592    fn set_peer_params(&mut self, params: TransportParameters) {
+6593        self.streams.set_params(&params);
+6594        self.idle_timeout =
+6595            negotiate_max_idle_timeout(self.config.max_idle_timeout, Some(params.max_idle_timeout));
+6596        trace!("negotiated max idle timeout {:?}", self.idle_timeout);
+6597
+6598        if let Some(ref info) = params.preferred_address {
+6599            // During the handshake PathId::ZERO exists.
+6600            self.remote_cids.get_mut(&PathId::ZERO).expect("not yet abandoned").insert(frame::NewConnectionId {
+6601                path_id: None,
+6602                sequence: 1,
+6603                id: info.connection_id,
+6604                reset_token: info.stateless_reset_token,
+6605                retire_prior_to: 0,
+6606            })
+6607            .expect(
+6608                "preferred address CID is the first received, and hence is guaranteed to be legal",
+6609            );
+6610            let remote = self.path_data(PathId::ZERO).network_path.remote;
+6611            self.set_reset_token(PathId::ZERO, remote, info.stateless_reset_token);
+6612        }
+6613        self.ack_frequency.peer_max_ack_delay = get_max_ack_delay(&params);
+6614
+6615        let mut multipath_enabled = None;
+6616        if let (Some(local_max_path_id), Some(remote_max_path_id)) = (
+6617            self.config.get_initial_max_path_id(),
+6618            params.initial_max_path_id,
+6619        ) {
+6620            // multipath is enabled, register the local and remote maximums
+6621            self.local_max_path_id = local_max_path_id;
+6622            self.remote_max_path_id = remote_max_path_id;
+6623            let initial_max_path_id = local_max_path_id.min(remote_max_path_id);
+6624            debug!(%initial_max_path_id, "multipath negotiated");
+6625            multipath_enabled = Some(initial_max_path_id);
+6626        }
+6627
+6628        if let Some((max_locally_allowed_remote_addresses, max_remotely_allowed_remote_addresses)) =
+6629            self.config
+6630                .max_remote_nat_traversal_addresses
+6631                .zip(params.max_remote_nat_traversal_addresses)
+6632        {
+6633            if let Some(max_initial_paths) =
+6634                multipath_enabled.map(|path_id| path_id.saturating_add(1u8))
+6635            {
+6636                let max_local_addresses = max_remotely_allowed_remote_addresses.get();
+6637                let max_remote_addresses = max_locally_allowed_remote_addresses.get();
+6638                self.n0_nat_traversal = n0_nat_traversal::State::new(
+6639                    max_remote_addresses,
+6640                    max_local_addresses,
+6641                    self.side(),
+6642                );
+6643                debug!(
+6644                    %max_remote_addresses, %max_local_addresses,
+6645                    "n0's nat traversal negotiated"
+6646                );
+6647
+6648                match self.side() {
+6649                    Side::Client => {
+6650                        if max_initial_paths.as_u32() < max_remote_addresses as u32 + 1 {
+6651                            // in this case the client might try to open `max_remote_addresses` new
+6652                            // paths, but the current multipath configuration will not allow it
+6653                            debug!(%max_initial_paths, %max_remote_addresses, "local client configuration might cause nat traversal issues")
+6654                        } else if max_local_addresses as u64
+6655                            > params.active_connection_id_limit.into_inner()
+6656                        {
+6657                            // the server allows us to send at most `params.active_connection_id_limit`
+6658                            // but they might need at least `max_local_addresses` to effectively send
+6659                            // `PATH_CHALLENGE` frames to each advertised local address
+6660                            debug!(%max_local_addresses, remote_cid_limit=%params.active_connection_id_limit.into_inner(), "remote server configuration might cause nat traversal issues")
+6661                        }
+6662                    }
+6663                    Side::Server => {
+6664                        if (max_initial_paths.as_u32() as u64) < crate::LOCAL_CID_COUNT {
+6665                            debug!(%max_initial_paths, local_cid_limit=%crate::LOCAL_CID_COUNT, "local server configuration might cause nat traversal issues")
+6666                        }
+6667                    }
+6668                }
+6669            } else {
+6670                debug!("n0 nat traversal enabled for both endpoints, but multipath is missing")
+6671            }
+6672        }
 6673
-6674        if result.outgoing_key_update_acked
-6675            && let Some(prev) = self.crypto_state.prev_crypto.as_mut()
-6676        {
-6677            prev.end_packet = Some((result.packet_number, now));
-6678            self.set_key_discard_timer(now, packet.header.space());
-6679        }
-6680
-6681        if result.incoming_key_update {
-6682            trace!("key update authenticated");
-6683            self.crypto_state
-6684                .update_keys(Some((result.packet_number, now)), true);
-6685            self.set_key_discard_timer(now, packet.header.space());
-6686        }
-6687
-6688        Ok(Some(result.packet_number))
-6689    }
-6690
-6691    fn peer_supports_ack_frequency(&self) -> bool {
-6692        self.peer_params.min_ack_delay.is_some()
-6693    }
-6694
-6695    /// Send an IMMEDIATE_ACK frame to the remote endpoint
-6696    ///
-6697    /// According to the spec, this will result in an error if the remote endpoint does not support
-6698    /// the Acknowledgement Frequency extension
-6699    pub(crate) fn immediate_ack(&mut self, path_id: PathId) {
-6700        debug_assert_eq!(
-6701            self.highest_space,
-6702            SpaceKind::Data,
-6703            "immediate ack must be written in the data space"
-6704        );
-6705        self.spaces[SpaceId::Data]
-6706            .for_path(path_id)
-6707            .immediate_ack_pending = true;
-6708    }
-6709
-6710    /// Decodes a packet, returning its decrypted payload, so it can be inspected in tests
-6711    #[cfg(test)]
-6712    pub(crate) fn decode_packet(&self, event: &ConnectionEvent) -> Option<Vec<u8>> {
-6713        let ConnectionEventInner::Datagram(DatagramConnectionEvent {
-6714            path_id,
-6715            first_decode,
-6716            remaining,
-6717            ..
-6718        }) = &event.0
-6719        else {
-6720            return None;
-6721        };
-6722
-6723        if remaining.is_some() {
-6724            panic!("Packets should never be coalesced in tests");
-6725        }
-6726
-6727        let decrypted_header = self
-6728            .crypto_state
-6729            .unprotect_header(first_decode.clone(), self.peer_params.stateless_reset_token)?;
-6730
-6731        let mut packet = decrypted_header.packet?;
-6732        self.crypto_state
-6733            .decrypt_packet_body(&mut packet, *path_id, &self.spaces)
-6734            .ok()?;
-6735
-6736        Some(packet.payload.to_vec())
-6737    }
-6738
-6739    /// The number of bytes of packets containing retransmittable frames that have not been
-6740    /// acknowledged or declared lost.
-6741    #[cfg(test)]
-6742    pub(crate) fn bytes_in_flight(&self) -> u64 {
-6743        // TODO(@divma): consider including for multipath?
-6744        self.path_data(PathId::ZERO).in_flight.bytes
-6745    }
-6746
-6747    /// Number of bytes worth of non-ack-only packets that may be sent
-6748    #[cfg(test)]
-6749    pub(crate) fn congestion_window(&self) -> u64 {
-6750        let path = self.path_data(PathId::ZERO);
-6751        path.congestion
-6752            .window()
-6753            .saturating_sub(path.in_flight.bytes)
-6754    }
-6755
-6756    /// Whether no timers but keepalive, idle, rtt, pushnewcid, and key discard are running
-6757    #[cfg(test)]
-6758    pub(crate) fn is_idle(&self) -> bool {
-6759        let current_timers = self.timers.values();
-6760        current_timers
-6761            .into_iter()
-6762            .filter(|(timer, _)| {
-6763                !matches!(
-6764                    timer,
-6765                    Timer::Conn(ConnTimer::KeepAlive)
-6766                        | Timer::PerPath(_, PathTimer::PathKeepAlive)
-6767                        | Timer::Conn(ConnTimer::PushNewCid)
-6768                        | Timer::Conn(ConnTimer::KeyDiscard)
-6769                )
-6770            })
-6771            .min_by_key(|(_, time)| *time)
-6772            .is_none_or(|(timer, _)| {
-6773                matches!(
-6774                    timer,
-6775                    Timer::Conn(ConnTimer::Idle) | Timer::PerPath(_, PathTimer::PathIdle)
-6776                )
-6777            })
-6778    }
-6779
-6780    /// Whether explicit congestion notification is in use on outgoing packets.
-6781    #[cfg(test)]
-6782    pub(crate) fn using_ecn(&self) -> bool {
-6783        self.path_data(PathId::ZERO).sending_ecn
-6784    }
-6785
-6786    /// The number of received bytes in the current path
-6787    #[cfg(test)]
-6788    pub(crate) fn total_recvd(&self) -> u64 {
-6789        self.path_data(PathId::ZERO).total_recvd
-6790    }
-6791
-6792    #[cfg(test)]
-6793    pub(crate) fn active_local_cid_seq(&self) -> (u64, u64) {
-6794        self.local_cid_state
-6795            .get(&PathId::ZERO)
-6796            .unwrap()
-6797            .active_seq()
-6798    }
-6799
-6800    #[cfg(test)]
-6801    #[track_caller]
-6802    pub(crate) fn active_local_path_cid_seq(&self, path_id: u32) -> (u64, u64) {
-6803        self.local_cid_state
-6804            .get(&PathId(path_id))
-6805            .unwrap()
-6806            .active_seq()
+6674        self.peer_params = params;
+6675        let peer_max_udp_payload_size =
+6676            u16::try_from(self.peer_params.max_udp_payload_size.into_inner()).unwrap_or(u16::MAX);
+6677        self.path_data_mut(PathId::ZERO)
+6678            .mtud
+6679            .on_peer_max_udp_payload_size_received(peer_max_udp_payload_size);
+6680    }
+6681
+6682    /// Decrypts a packet, returning the packet number on success
+6683    fn decrypt_packet(
+6684        &mut self,
+6685        now: Instant,
+6686        path_id: PathId,
+6687        packet: &mut Packet,
+6688    ) -> Result<Option<u64>, Option<TransportError>> {
+6689        let result = self
+6690            .crypto_state
+6691            .decrypt_packet_body(packet, path_id, &self.spaces)?;
+6692
+6693        let Some(result) = result else {
+6694            return Ok(None);
+6695        };
+6696
+6697        if result.outgoing_key_update_acked
+6698            && let Some(prev) = self.crypto_state.prev_crypto.as_mut()
+6699        {
+6700            prev.end_packet = Some((result.packet_number, now));
+6701            self.set_key_discard_timer(now, packet.header.space());
+6702        }
+6703
+6704        if result.incoming_key_update {
+6705            trace!("key update authenticated");
+6706            self.crypto_state
+6707                .update_keys(Some((result.packet_number, now)), true);
+6708            self.set_key_discard_timer(now, packet.header.space());
+6709        }
+6710
+6711        Ok(Some(result.packet_number))
+6712    }
+6713
+6714    fn peer_supports_ack_frequency(&self) -> bool {
+6715        self.peer_params.min_ack_delay.is_some()
+6716    }
+6717
+6718    /// Send an IMMEDIATE_ACK frame to the remote endpoint
+6719    ///
+6720    /// According to the spec, this will result in an error if the remote endpoint does not support
+6721    /// the Acknowledgement Frequency extension
+6722    pub(crate) fn immediate_ack(&mut self, path_id: PathId) {
+6723        debug_assert_eq!(
+6724            self.highest_space,
+6725            SpaceKind::Data,
+6726            "immediate ack must be written in the data space"
+6727        );
+6728        self.spaces[SpaceId::Data]
+6729            .for_path(path_id)
+6730            .immediate_ack_pending = true;
+6731    }
+6732
+6733    /// Decodes a packet, returning its decrypted payload, so it can be inspected in tests
+6734    #[cfg(test)]
+6735    pub(crate) fn decode_packet(&self, event: &ConnectionEvent) -> Option<Vec<u8>> {
+6736        let ConnectionEventInner::Datagram(DatagramConnectionEvent {
+6737            path_id,
+6738            first_decode,
+6739            remaining,
+6740            ..
+6741        }) = &event.0
+6742        else {
+6743            return None;
+6744        };
+6745
+6746        if remaining.is_some() {
+6747            panic!("Packets should never be coalesced in tests");
+6748        }
+6749
+6750        let decrypted_header = self
+6751            .crypto_state
+6752            .unprotect_header(first_decode.clone(), self.peer_params.stateless_reset_token)?;
+6753
+6754        let mut packet = decrypted_header.packet?;
+6755        self.crypto_state
+6756            .decrypt_packet_body(&mut packet, *path_id, &self.spaces)
+6757            .ok()?;
+6758
+6759        Some(packet.payload.to_vec())
+6760    }
+6761
+6762    /// The number of bytes of packets containing retransmittable frames that have not been
+6763    /// acknowledged or declared lost.
+6764    #[cfg(test)]
+6765    pub(crate) fn bytes_in_flight(&self) -> u64 {
+6766        // TODO(@divma): consider including for multipath?
+6767        self.path_data(PathId::ZERO).in_flight.bytes
+6768    }
+6769
+6770    /// Number of bytes worth of non-ack-only packets that may be sent
+6771    #[cfg(test)]
+6772    pub(crate) fn congestion_window(&self) -> u64 {
+6773        let path = self.path_data(PathId::ZERO);
+6774        path.congestion
+6775            .window()
+6776            .saturating_sub(path.in_flight.bytes)
+6777    }
+6778
+6779    /// Whether no timers but keepalive, idle, rtt, pushnewcid, and key discard are running
+6780    #[cfg(test)]
+6781    pub(crate) fn is_idle(&self) -> bool {
+6782        let current_timers = self.timers.values();
+6783        current_timers
+6784            .into_iter()
+6785            .filter(|(timer, _)| {
+6786                !matches!(
+6787                    timer,
+6788                    Timer::Conn(ConnTimer::KeepAlive)
+6789                        | Timer::PerPath(_, PathTimer::PathKeepAlive)
+6790                        | Timer::Conn(ConnTimer::PushNewCid)
+6791                        | Timer::Conn(ConnTimer::KeyDiscard)
+6792                )
+6793            })
+6794            .min_by_key(|(_, time)| *time)
+6795            .is_none_or(|(timer, _)| {
+6796                matches!(
+6797                    timer,
+6798                    Timer::Conn(ConnTimer::Idle) | Timer::PerPath(_, PathTimer::PathIdle)
+6799                )
+6800            })
+6801    }
+6802
+6803    /// Whether explicit congestion notification is in use on outgoing packets.
+6804    #[cfg(test)]
+6805    pub(crate) fn using_ecn(&self) -> bool {
+6806        self.path_data(PathId::ZERO).sending_ecn
 6807    }
 6808
-6809    /// Instruct the peer to replace previously issued CIDs by sending a NEW_CONNECTION_ID frame
-6810    /// with updated `retire_prior_to` field set to `v`
-6811    #[cfg(test)]
-6812    pub(crate) fn rotate_local_cid(&mut self, v: u64, now: Instant) {
-6813        let n = self
-6814            .local_cid_state
-6815            .get_mut(&PathId::ZERO)
-6816            .unwrap()
-6817            .assign_retire_seq(v);
-6818        debug_assert!(!self.state.is_drained()); // requirement for endpoint_events
-6819        self.endpoint_events
-6820            .push_back(EndpointEventInner::NeedIdentifiers(PathId::ZERO, now, n));
+6809    /// The number of received bytes in the current path
+6810    #[cfg(test)]
+6811    pub(crate) fn total_recvd(&self) -> u64 {
+6812        self.path_data(PathId::ZERO).total_recvd
+6813    }
+6814
+6815    #[cfg(test)]
+6816    pub(crate) fn active_local_cid_seq(&self) -> (u64, u64) {
+6817        self.local_cid_state
+6818            .get(&PathId::ZERO)
+6819            .unwrap()
+6820            .active_seq()
 6821    }
 6822
-6823    /// Check the current active remote CID sequence for `PathId::ZERO`
-6824    #[cfg(test)]
-6825    pub(crate) fn active_remote_cid_seq(&self) -> u64 {
-6826        self.remote_cids.get(&PathId::ZERO).unwrap().active_seq()
-6827    }
-6828
-6829    /// Returns the detected maximum udp payload size for the current path
-6830    #[cfg(test)]
-6831    pub(crate) fn path_mtu(&self, path_id: PathId) -> u16 {
-6832        self.path_data(path_id).current_mtu()
-6833    }
-6834
-6835    /// Triggers path validation on all paths
-6836    #[cfg(test)]
-6837    pub(crate) fn trigger_path_validation(&mut self) {
-6838        for path in self.paths.values_mut() {
-6839            path.data.pending_on_path_challenge = true;
-6840        }
-6841    }
-6842
-6843    /// Simulates a protocol violation error for test purposes.
-6844    #[cfg(test)]
-6845    pub fn simulate_protocol_violation(&mut self, now: Instant) {
-6846        if !self.state.is_closed() {
-6847            self.state
-6848                .move_to_closed(TransportError::PROTOCOL_VIOLATION("simulated violation"));
-6849            self.close_common();
-6850            if !self.state.is_drained() {
-6851                self.set_close_timer(now);
-6852            }
-6853            self.connection_close_pending = true;
-6854        }
-6855    }
-6856
-6857    /// Whether we have on-path 1-RTT data to send.
-6858    ///
-6859    /// This checks for frames that can only be sent in the data space (1-RTT):
-6860    /// - Pending PATH_CHALLENGE frames on the active and previous path if just migrated.
-6861    /// - Pending PATH_RESPONSE frames.
-6862    /// - Pending data to send in STREAM frames.
-6863    /// - Pending DATAGRAM frames to send.
-6864    ///
-6865    /// See also [`PacketSpace::can_send`] which keeps track of all other frame types that
-6866    /// may need to be sent.
-6867    fn can_send_1rtt(&self, path_id: PathId, max_size: usize) -> SendableFrames {
-6868        let space_specific = self.paths.get(&path_id).is_some_and(|path| {
-6869            path.data.pending_on_path_challenge || !path.data.path_responses.is_empty()
-6870        });
-6871
-6872        // Stream control frames are checked in PacketSpace::can_send, only check data here.
-6873        let other = self.streams.can_send_stream_data()
-6874            || self
-6875                .datagrams
-6876                .outgoing
-6877                .front()
-6878                .is_some_and(|x| x.size(true) <= max_size);
+6823    #[cfg(test)]
+6824    #[track_caller]
+6825    pub(crate) fn active_local_path_cid_seq(&self, path_id: u32) -> (u64, u64) {
+6826        self.local_cid_state
+6827            .get(&PathId(path_id))
+6828            .unwrap()
+6829            .active_seq()
+6830    }
+6831
+6832    /// Instruct the peer to replace previously issued CIDs by sending a NEW_CONNECTION_ID frame
+6833    /// with updated `retire_prior_to` field set to `v`
+6834    #[cfg(test)]
+6835    pub(crate) fn rotate_local_cid(&mut self, v: u64, now: Instant) {
+6836        let n = self
+6837            .local_cid_state
+6838            .get_mut(&PathId::ZERO)
+6839            .unwrap()
+6840            .assign_retire_seq(v);
+6841        debug_assert!(!self.state.is_drained()); // requirement for endpoint_events
+6842        self.endpoint_events
+6843            .push_back(EndpointEventInner::NeedIdentifiers(PathId::ZERO, now, n));
+6844    }
+6845
+6846    /// Check the current active remote CID sequence for `PathId::ZERO`
+6847    #[cfg(test)]
+6848    pub(crate) fn active_remote_cid_seq(&self) -> u64 {
+6849        self.remote_cids.get(&PathId::ZERO).unwrap().active_seq()
+6850    }
+6851
+6852    /// Returns the detected maximum udp payload size for the current path
+6853    #[cfg(test)]
+6854    pub(crate) fn path_mtu(&self, path_id: PathId) -> u16 {
+6855        self.path_data(path_id).current_mtu()
+6856    }
+6857
+6858    /// Triggers path validation on all paths
+6859    #[cfg(test)]
+6860    pub(crate) fn trigger_path_validation(&mut self) {
+6861        for path in self.paths.values_mut() {
+6862            path.data.pending_on_path_challenge = true;
+6863        }
+6864    }
+6865
+6866    /// Simulates a protocol violation error for test purposes.
+6867    #[cfg(test)]
+6868    pub fn simulate_protocol_violation(&mut self, now: Instant) {
+6869        if !self.state.is_closed() {
+6870            self.state
+6871                .move_to_closed(TransportError::PROTOCOL_VIOLATION("simulated violation"));
+6872            self.close_common();
+6873            if !self.state.is_drained() {
+6874                self.set_close_timer(now);
+6875            }
+6876            self.connection_close_pending = true;
+6877        }
+6878    }
 6879
-6880        // All `false` fields are set in PacketSpace::can_send.
-6881        SendableFrames {
-6882            acks: false,
-6883            close: false,
-6884            space_specific,
-6885            other,
-6886        }
-6887    }
-6888
-6889    /// Terminate the connection instantly, without sending a close packet
-6890    fn kill(&mut self, reason: ConnectionError) {
-6891        self.close_common();
-6892        self.state.move_to_drained(Some(reason));
-6893        // move_to_drained checks that we were never in drained before, so we
-6894        // never sent a `Drained` event before (it's illegal to send more events after drained).
-6895        self.endpoint_events.push_back(EndpointEventInner::Drained);
-6896    }
-6897
-6898    /// Storage size required for the largest packet that can be transmitted on all currently
-6899    /// available paths
-6900    ///
-6901    /// Buffers passed to [`Connection::poll_transmit`] should be at least this large.
-6902    ///
-6903    /// When multipath is enabled, this value is the minimum MTU across all available paths.
-6904    pub fn current_mtu(&self) -> u16 {
-6905        self.paths
-6906            .iter()
-6907            .filter(|&(path_id, _path_state)| !self.abandoned_paths.contains(path_id))
-6908            .map(|(_path_id, path_state)| path_state.data.current_mtu())
-6909            .min()
-6910            .unwrap_or(INITIAL_MTU)
-6911    }
-6912
-6913    /// Size of non-frame data for a 1-RTT packet
-6914    ///
-6915    /// Quantifies space consumed by the QUIC header and AEAD tag. All other bytes in a packet are
-6916    /// frames. Changes if the length of the remote connection ID changes, which is expected to be
-6917    /// rare. If `pn` is specified, may additionally change unpredictably due to variations in
-6918    /// latency and packet loss.
-6919    fn predict_1rtt_overhead(&mut self, pn: u64, path: PathId) -> usize {
-6920        let pn_len = PacketNumber::new(
-6921            pn,
-6922            self.spaces[SpaceId::Data]
-6923                .for_path(path)
-6924                .largest_acked_packet_pn
-6925                .unwrap_or(0),
-6926        )
-6927        .len();
-6928
-6929        // 1 byte for flags
-6930        1 + self
-6931            .remote_cids
-6932            .get(&path)
-6933            .map(|cids| cids.active().len())
-6934            .unwrap_or(20)      // Max CID len in QUIC v1
-6935            + pn_len
-6936            + self.tag_len_1rtt()
-6937    }
-6938
-6939    fn predict_1rtt_overhead_no_pn(&self) -> usize {
-6940        let pn_len = 4;
-6941
-6942        let cid_len = self
-6943            .remote_cids
-6944            .values()
-6945            .map(|cids| cids.active().len())
-6946            .max()
-6947            .unwrap_or(20); // Max CID len in QUIC v1
-6948
-6949        // 1 byte for flags
-6950        1 + cid_len + pn_len + self.tag_len_1rtt()
-6951    }
-6952
-6953    fn tag_len_1rtt(&self) -> usize {
-6954        // encryption_keys for Data space returns 1-RTT keys if available, otherwise 0-RTT keys
-6955        let packet_crypto = self
-6956            .crypto_state
-6957            .encryption_keys(SpaceKind::Data, self.side.side())
-6958            .map(|(_header, packet, _level)| packet);
-6959        // If neither Data nor 0-RTT keys are available, make a reasonable tag length guess. As of
-6960        // this writing, all QUIC cipher suites use 16-byte tags. We could return `None` instead,
-6961        // but that would needlessly prevent sending datagrams during 0-RTT.
-6962        packet_crypto.map_or(16, |x| x.tag_len())
-6963    }
+6880    /// Whether we have on-path 1-RTT data to send.
+6881    ///
+6882    /// This checks for frames that can only be sent in the data space (1-RTT):
+6883    /// - Pending PATH_CHALLENGE frames on the active and previous path if just migrated.
+6884    /// - Pending PATH_RESPONSE frames.
+6885    /// - Pending data to send in STREAM frames.
+6886    /// - Pending DATAGRAM frames to send.
+6887    ///
+6888    /// See also [`PacketSpace::can_send`] which keeps track of all other frame types that
+6889    /// may need to be sent.
+6890    fn can_send_1rtt(&self, path_id: PathId, max_size: usize) -> SendableFrames {
+6891        let space_specific = self.paths.get(&path_id).is_some_and(|path| {
+6892            path.data.pending_on_path_challenge || !path.data.path_responses.is_empty()
+6893        });
+6894
+6895        // Stream control frames are checked in PacketSpace::can_send, only check data here.
+6896        let other = self.streams.can_send_stream_data()
+6897            || self
+6898                .datagrams
+6899                .outgoing
+6900                .front()
+6901                .is_some_and(|x| x.size(true) <= max_size);
+6902
+6903        // All `false` fields are set in PacketSpace::can_send.
+6904        SendableFrames {
+6905            acks: false,
+6906            close: false,
+6907            space_specific,
+6908            other,
+6909        }
+6910    }
+6911
+6912    /// Terminate the connection instantly, without sending a close packet
+6913    fn kill(&mut self, reason: ConnectionError) {
+6914        self.close_common();
+6915        self.state.move_to_drained(Some(reason));
+6916        // move_to_drained checks that we were never in drained before, so we
+6917        // never sent a `Drained` event before (it's illegal to send more events after drained).
+6918        self.endpoint_events.push_back(EndpointEventInner::Drained);
+6919    }
+6920
+6921    /// Storage size required for the largest packet that can be transmitted on all currently
+6922    /// available paths
+6923    ///
+6924    /// Buffers passed to [`Connection::poll_transmit`] should be at least this large.
+6925    ///
+6926    /// When multipath is enabled, this value is the minimum MTU across all available paths.
+6927    pub fn current_mtu(&self) -> u16 {
+6928        self.paths
+6929            .iter()
+6930            .filter(|&(path_id, _path_state)| !self.abandoned_paths.contains(path_id))
+6931            .map(|(_path_id, path_state)| path_state.data.current_mtu())
+6932            .min()
+6933            .unwrap_or(INITIAL_MTU)
+6934    }
+6935
+6936    /// Size of non-frame data for a 1-RTT packet
+6937    ///
+6938    /// Quantifies space consumed by the QUIC header and AEAD tag. All other bytes in a packet are
+6939    /// frames. Changes if the length of the remote connection ID changes, which is expected to be
+6940    /// rare. If `pn` is specified, may additionally change unpredictably due to variations in
+6941    /// latency and packet loss.
+6942    fn predict_1rtt_overhead(&mut self, pn: u64, path: PathId) -> usize {
+6943        let pn_len = PacketNumber::new(
+6944            pn,
+6945            self.spaces[SpaceId::Data]
+6946                .for_path(path)
+6947                .largest_acked_packet_pn
+6948                .unwrap_or(0),
+6949        )
+6950        .len();
+6951
+6952        // 1 byte for flags
+6953        1 + self
+6954            .remote_cids
+6955            .get(&path)
+6956            .map(|cids| cids.active().len())
+6957            .unwrap_or(20)      // Max CID len in QUIC v1
+6958            + pn_len
+6959            + self.tag_len_1rtt()
+6960    }
+6961
+6962    fn predict_1rtt_overhead_no_pn(&self) -> usize {
+6963        let pn_len = 4;
 6964
-6965    /// Mark the path as validated, and enqueue NEW_TOKEN frames to be sent as appropriate
-6966    fn on_path_validated(&mut self, path_id: PathId) {
-6967        self.path_data_mut(path_id).validated = true;
-6968        let ConnectionSide::Server { server_config } = &self.side else {
-6969            return;
-6970        };
-6971        let network_path = self.path_data(path_id).network_path;
-6972        let new_tokens = &mut self.spaces[SpaceId::Data as usize].pending.new_tokens;
-6973        new_tokens.clear();
-6974        for _ in 0..server_config.validation_token.sent {
-6975            new_tokens.push(network_path);
-6976        }
-6977    }
-6978
-6979    /// Handle new path status information: PATH_STATUS_AVAILABLE, PATH_STATUS_BACKUP
-6980    fn on_path_status(&mut self, path_id: PathId, status: PathStatus, status_seq_no: VarInt) {
-6981        if let Some(path) = self.paths.get_mut(&path_id) {
-6982            path.data.status.remote_update(status, status_seq_no);
-6983        } else {
-6984            debug!("PATH_STATUS_AVAILABLE received unknown path {:?}", path_id);
-6985        }
-6986        self.events.push_back(
-6987            PathEvent::RemoteStatus {
-6988                id: path_id,
-6989                status,
-6990            }
-6991            .into(),
-6992        );
-6993    }
-6994
-6995    /// Returns the maximum [`PathId`] to be used for sending in this connection.
-6996    ///
-6997    /// This is calculated as minimum between the local and remote's maximums when multipath is
-6998    /// enabled, or `None` when disabled.
-6999    ///
-7000    /// For data that's received, we should use [`Self::local_max_path_id`] instead.
-7001    /// The reasoning is that the remote might already have updated to its own newer
-7002    /// [`Self::max_path_id`] after sending out a `MAX_PATH_ID` frame, but it got re-ordered.
-7003    fn max_path_id(&self) -> Option<PathId> {
-7004        if self.is_multipath_negotiated() {
-7005            Some(self.remote_max_path_id.min(self.local_max_path_id))
+6965        let cid_len = self
+6966            .remote_cids
+6967            .values()
+6968            .map(|cids| cids.active().len())
+6969            .max()
+6970            .unwrap_or(20); // Max CID len in QUIC v1
+6971
+6972        // 1 byte for flags
+6973        1 + cid_len + pn_len + self.tag_len_1rtt()
+6974    }
+6975
+6976    fn tag_len_1rtt(&self) -> usize {
+6977        // encryption_keys for Data space returns 1-RTT keys if available, otherwise 0-RTT keys
+6978        let packet_crypto = self
+6979            .crypto_state
+6980            .encryption_keys(SpaceKind::Data, self.side.side())
+6981            .map(|(_header, packet, _level)| packet);
+6982        // If neither Data nor 0-RTT keys are available, make a reasonable tag length guess. As of
+6983        // this writing, all QUIC cipher suites use 16-byte tags. We could return `None` instead,
+6984        // but that would needlessly prevent sending datagrams during 0-RTT.
+6985        packet_crypto.map_or(16, |x| x.tag_len())
+6986    }
+6987
+6988    /// Mark the path as validated, and enqueue NEW_TOKEN frames to be sent as appropriate
+6989    fn on_path_validated(&mut self, path_id: PathId) {
+6990        self.path_data_mut(path_id).validated = true;
+6991        let ConnectionSide::Server { server_config } = &self.side else {
+6992            return;
+6993        };
+6994        let network_path = self.path_data(path_id).network_path;
+6995        let new_tokens = &mut self.spaces[SpaceId::Data as usize].pending.new_tokens;
+6996        new_tokens.clear();
+6997        for _ in 0..server_config.validation_token.sent {
+6998            new_tokens.push(network_path);
+6999        }
+7000    }
+7001
+7002    /// Handle new path status information: PATH_STATUS_AVAILABLE, PATH_STATUS_BACKUP
+7003    fn on_path_status(&mut self, path_id: PathId, status: PathStatus, status_seq_no: VarInt) {
+7004        if let Some(path) = self.paths.get_mut(&path_id) {
+7005            path.data.status.remote_update(status, status_seq_no);
 7006        } else {
-7007            None
-7008        }
-7009    }
-7010
-7011    /// Returns whether this connection has a socket that supports IPv6.
-7012    ///
-7013    /// TODO(matheus23): This is related to noq endpoint state's `ipv6` bool. We should move that info
-7014    /// here instead of trying to hack around not knowing it exactly.
-7015    fn is_ipv6(&self) -> bool {
-7016        self.paths
-7017            .values()
-7018            .any(|p| p.data.network_path.remote.is_ipv6())
-7019    }
-7020
-7021    /// Add addresses the local endpoint considers are reachable for nat traversal.
-7022    pub fn add_nat_traversal_address(
-7023        &mut self,
-7024        address: SocketAddr,
-7025    ) -> Result<(), n0_nat_traversal::Error> {
-7026        if let Some(added) = self.n0_nat_traversal.add_local_address(address)? {
-7027            self.spaces[SpaceId::Data].pending.add_address.insert(added);
-7028        };
-7029        Ok(())
-7030    }
-7031
-7032    /// Removes an address the endpoing no longer considers reachable for nat traversal
-7033    ///
-7034    /// Addresses not present in the set will be silently ignored.
-7035    pub fn remove_nat_traversal_address(
-7036        &mut self,
-7037        address: SocketAddr,
-7038    ) -> Result<(), n0_nat_traversal::Error> {
-7039        if let Some(removed) = self.n0_nat_traversal.remove_local_address(address)? {
-7040            self.spaces[SpaceId::Data]
-7041                .pending
-7042                .remove_address
-7043                .insert(removed);
-7044        }
-7045        Ok(())
-7046    }
-7047
-7048    /// Get the current local nat traversal addresses
-7049    pub fn get_local_nat_traversal_addresses(
-7050        &self,
-7051    ) -> Result<Vec<SocketAddr>, n0_nat_traversal::Error> {
-7052        self.n0_nat_traversal.get_local_nat_traversal_addresses()
+7007            debug!("PATH_STATUS_AVAILABLE received unknown path {:?}", path_id);
+7008        }
+7009        self.events.push_back(
+7010            PathEvent::RemoteStatus {
+7011                id: path_id,
+7012                status,
+7013            }
+7014            .into(),
+7015        );
+7016    }
+7017
+7018    /// Returns the maximum [`PathId`] to be used for sending in this connection.
+7019    ///
+7020    /// This is calculated as minimum between the local and remote's maximums when multipath is
+7021    /// enabled, or `None` when disabled.
+7022    ///
+7023    /// For data that's received, we should use [`Self::local_max_path_id`] instead.
+7024    /// The reasoning is that the remote might already have updated to its own newer
+7025    /// [`Self::max_path_id`] after sending out a `MAX_PATH_ID` frame, but it got re-ordered.
+7026    fn max_path_id(&self) -> Option<PathId> {
+7027        if self.is_multipath_negotiated() {
+7028            Some(self.remote_max_path_id.min(self.local_max_path_id))
+7029        } else {
+7030            None
+7031        }
+7032    }
+7033
+7034    /// Returns whether this connection has a socket that supports IPv6.
+7035    ///
+7036    /// TODO(matheus23): This is related to noq endpoint state's `ipv6` bool. We should move that info
+7037    /// here instead of trying to hack around not knowing it exactly.
+7038    fn is_ipv6(&self) -> bool {
+7039        self.paths
+7040            .values()
+7041            .any(|p| p.data.network_path.remote.is_ipv6())
+7042    }
+7043
+7044    /// Add addresses the local endpoint considers are reachable for nat traversal.
+7045    pub fn add_nat_traversal_address(
+7046        &mut self,
+7047        address: SocketAddr,
+7048    ) -> Result<(), n0_nat_traversal::Error> {
+7049        if let Some(added) = self.n0_nat_traversal.add_local_address(address)? {
+7050            self.spaces[SpaceId::Data].pending.add_address.insert(added);
+7051        };
+7052        Ok(())
 7053    }
 7054
-7055    /// Get the currently advertised nat traversal addresses by the server
-7056    pub fn get_remote_nat_traversal_addresses(
-7057        &self,
-7058    ) -> Result<Vec<SocketAddr>, n0_nat_traversal::Error> {
-7059        Ok(self
-7060            .n0_nat_traversal
-7061            .client_side()?
-7062            .get_remote_nat_traversal_addresses())
-7063    }
-7064
-7065    /// Attempts to open a path for nat traversal.
-7066    ///
-7067    /// On success returns the [`PathId`] and remote address of the path.
-7068    fn open_nat_traversal_path(
-7069        &mut self,
-7070        now: Instant,
-7071        ip_port: (IpAddr, u16),
-7072    ) -> Result<Option<(PathId, SocketAddr)>, PathError> {
-7073        let remote = ip_port.into();
-7074        // TODO(matheus23): Probe the correct 4-tuple, instead of only a remote address?
-7075        // By specifying None for `local_ip`, we do two things: 1. open_path_ensure won't
-7076        // generate two paths to the same remote and 2. we let the OS choose which
-7077        // interface to use for sending on that path.
-7078        let network_path = FourTuple {
-7079            remote,
-7080            local_ip: None,
-7081        };
-7082        match self.open_path_ensure(network_path, PathStatus::Backup, now) {
-7083            Ok((path_id, path_was_known)) => {
-7084                if path_was_known {
-7085                    trace!(%path_id, %remote, "nat traversal: path existed for remote, revalidating");
-7086                    if let Some(path) = self.paths.get_mut(&path_id) {
-7087                        use paths::OpenStatus::*;
-7088
-7089                        path.data.pending_on_path_challenge = true;
-7090                        path.data.open_status = match path.data.open_status {
-7091                            // If we just opened the path and have never sent a `PATH_CHALLENGE` yet,
-7092                            // then we need to keep it at pending, to ensure that
-7093                            // 1. The PathOpenFailed timer for stopping the PathChallengeLost retries will be set.
-7094                            // 2. When validation eventually succeeds, then we inform the application layer about this path opening.
-7095                            Pending => Pending,
-7096                            // If we had already sent a path challenge in the past, but it hasn't been validated yet (and also not
-7097                            // failed via the PathOpenFailed timer yet), then we need to go back to pending, to ensure we properly
-7098                            // re-arm the `PathOpenFailed` timer again.
-7099                            Sent => Pending,
-7100                            // If we're already revalidating this path, but haven't sent a `PATH_CHALLENGE` yet, then we just keep
-7101                            // that state.
-7102                            Revalidating => Revalidating,
-7103                            // If we've informed the application layer about the path opening in the past, but we now re-send
-7104                            // PATH_CHALLENGEs for validation, then using this we ensure:
-7105                            // 1. The PathOpenFailed timer for stopping the PathChallengeLost retries will be set.
-7106                            // 2. When validation eventually succeeds, we *don't* inform the application layer about the path
-7107                            //    opening again.
-7108                            Informed => Revalidating,
-7109                        }
-7110                    }
-7111                }
-7112                Ok(Some((path_id, remote)))
-7113            }
-7114            Err(e) => {
-7115                debug!(%remote, %e, "nat traversal: failed to probe remote");
-7116                Err(e)
-7117            }
+7055    /// Removes an address the endpoing no longer considers reachable for nat traversal
+7056    ///
+7057    /// Addresses not present in the set will be silently ignored.
+7058    pub fn remove_nat_traversal_address(
+7059        &mut self,
+7060        address: SocketAddr,
+7061    ) -> Result<(), n0_nat_traversal::Error> {
+7062        if let Some(removed) = self.n0_nat_traversal.remove_local_address(address)? {
+7063            self.spaces[SpaceId::Data]
+7064                .pending
+7065                .remove_address
+7066                .insert(removed);
+7067        }
+7068        Ok(())
+7069    }
+7070
+7071    /// Get the current local nat traversal addresses
+7072    pub fn get_local_nat_traversal_addresses(
+7073        &self,
+7074    ) -> Result<Vec<SocketAddr>, n0_nat_traversal::Error> {
+7075        self.n0_nat_traversal.get_local_nat_traversal_addresses()
+7076    }
+7077
+7078    /// Get the currently advertised nat traversal addresses by the server
+7079    pub fn get_remote_nat_traversal_addresses(
+7080        &self,
+7081    ) -> Result<Vec<SocketAddr>, n0_nat_traversal::Error> {
+7082        Ok(self
+7083            .n0_nat_traversal
+7084            .client_side()?
+7085            .get_remote_nat_traversal_addresses())
+7086    }
+7087
+7088    /// Initiates a new nat traversal round
+7089    ///
+7090    /// A nat traversal round involves advertising the client's local addresses in
+7091    /// `REACH_OUT` frames, and initiating probing of the known remote addresses. When a new
+7092    /// round is initiated, the previous one is cancelled.
+7093    ///
+7094    /// For all probes that succeed, if any, a new path will be opened on the successful
+7095    /// 4-tuple.
+7096    ///
+7097    /// Returns the server addresses that are now being probed. If addresses fail due to
+7098    /// spurious errors, these might succeed later and not be returned in this set.
+7099    pub fn initiate_nat_traversal_round(
+7100        &mut self,
+7101        now: Instant,
+7102    ) -> Result<Vec<SocketAddr>, n0_nat_traversal::Error> {
+7103        if self.state.is_closed() {
+7104            return Err(n0_nat_traversal::Error::Closed);
+7105        }
+7106
+7107        let ipv6 = self.is_ipv6();
+7108        let client_state = self.n0_nat_traversal.client_side_mut()?;
+7109        let (mut reach_out_frames, probed_addrs) =
+7110            client_state.initiate_nat_traversal_round(ipv6)?;
+7111        if !probed_addrs.is_empty() {
+7112            let delay = RttEstimator::new(self.config.initial_rtt).pto_base() * 2 / 3;
+7113            self.timers.set(
+7114                Timer::Conn(ConnTimer::NatTraversalProbeRetry),
+7115                now + delay,
+7116                self.qlog.with_time(now),
+7117            );
 7118        }
-7119    }
-7120
-7121    /// Initiates a new nat traversal round
-7122    ///
-7123    /// A nat traversal round involves advertising the client's local addresses in
-7124    /// `REACH_OUT` frames, and initiating probing of the known remote addresses. When a new
-7125    /// round is initiated, the previous one is cancelled.
-7126    ///
-7127    /// For all probes that succeed, if any, a new path will be opened on the successful
-7128    /// 4-tuple.
+7119
+7120        self.spaces[SpaceId::Data]
+7121            .pending
+7122            .reach_out
+7123            .append(&mut reach_out_frames);
+7124
+7125        Ok(probed_addrs)
+7126    }
+7127
+7128    /// Whether the handshake is considered **confirmed**.
 7129    ///
-7130    /// Returns the server addresses that are now being probed. If addresses fail due to
-7131    /// spurious errors, these might succeed later and not be returned in this set.
-7132    pub fn initiate_nat_traversal_round(
-7133        &mut self,
-7134        now: Instant,
-7135    ) -> Result<Vec<SocketAddr>, n0_nat_traversal::Error> {
-7136        if self.state.is_closed() {
-7137            return Err(n0_nat_traversal::Error::Closed);
-7138        }
-7139
-7140        let ipv6 = self.is_ipv6();
-7141        let client_state = self.n0_nat_traversal.client_side_mut()?;
-7142        let n0_nat_traversal::NatTraversalRound {
-7143            new_round,
-7144            reach_out_at,
-7145            addresses_to_probe,
-7146            prev_round_path_ids,
-7147        } = client_state.initiate_nat_traversal_round(ipv6)?;
+7130    /// <https://www.rfc-editor.org/rfc/rfc9001#section-4.1.2> defines a handshake to be
+7131    /// confirmed when you know the peer successfully received and successfully processed
+7132    /// your TLS Finished message.
+7133    ///
+7134    /// Implementation-wise this is the point at which the handshake crypto keys are
+7135    /// discarded. So we can use this to know if the handshake is confirmed.
+7136    fn is_handshake_confirmed(&self) -> bool {
+7137        !self.is_handshaking() && !self.crypto_state.has_keys(EncryptionLevel::Handshake)
+7138    }
+7139}
+7140
+7141impl fmt::Debug for Connection {
+7142    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+7143        f.debug_struct("Connection")
+7144            .field("handshake_cid", &self.handshake_cid)
+7145            .finish()
+7146    }
+7147}
 7148
-7149        trace!(%new_round, reach_out=reach_out_at.len(), to_probe=addresses_to_probe.len(),
-7150            "initiating nat traversal round");
-7151
-7152        self.spaces[SpaceId::Data].pending.reach_out = Some((new_round, reach_out_at));
-7153
-7154        for path_id in prev_round_path_ids {
-7155            let Some(path) = self.path(path_id) else {
-7156                continue;
-7157            };
-7158            let ip = path.network_path.remote.ip();
-7159            let port = path.network_path.remote.port();
-7160
-7161            // We only close paths that aren't validated (thus are working) that we opened
-7162            // in a previous round.
-7163            // And we only close paths that we don't want to probe anyways.
-7164            if !addresses_to_probe
-7165                .iter()
-7166                .any(|(_, probe)| *probe == (ip, port))
-7167                && !path.validated
-7168                && !self.abandoned_paths.contains(&path_id)
-7169            {
-7170                trace!(%path_id, "closing path from previous round");
-7171                let _ =
-7172                    self.close_path_inner(now, path_id, PathAbandonReason::NatTraversalRoundEnded);
-7173            }
-7174        }
-7175
-7176        let mut err = None;
-7177
-7178        let mut path_ids = Vec::with_capacity(addresses_to_probe.len());
-7179        let mut probed_addresses = Vec::with_capacity(addresses_to_probe.len());
-7180
-7181        for (id, address) in addresses_to_probe {
-7182            match self.open_nat_traversal_path(now, address) {
-7183                Ok(None) => {}
-7184                Ok(Some((path_id, remote))) => {
-7185                    path_ids.push(path_id);
-7186                    probed_addresses.push(remote);
-7187                }
-7188                Err(e) => {
-7189                    self.n0_nat_traversal
-7190                        .client_side_mut()
-7191                        .expect("validated")
-7192                        .report_in_continuation(id, e);
-7193                    err.get_or_insert(e);
-7194                }
-7195            }
-7196        }
-7197
-7198        if let Some(err) = err {
-7199            // We failed to probe any addresses, bail out
-7200            if probed_addresses.is_empty() {
-7201                return Err(n0_nat_traversal::Error::Multipath(err));
-7202            }
-7203        }
-7204
-7205        self.n0_nat_traversal
-7206            .client_side_mut()
-7207            .expect("connection side validated")
-7208            .set_round_path_ids(path_ids);
-7209
-7210        Ok(probed_addresses)
-7211    }
-7212
-7213    /// Attempts to continue a nat traversal round by trying to open paths for pending client probes.
-7214    ///
-7215    /// If there was nothing to do, it returns `None`. Otherwise it returns whether the path was
-7216    /// successfully open.
-7217    fn continue_nat_traversal_round(&mut self, now: Instant) -> Option<bool> {
-7218        let ipv6 = self.is_ipv6();
-7219        let client_state = self.n0_nat_traversal.client_side_mut().ok()?;
-7220        let (id, address) = client_state.continue_nat_traversal_round(ipv6)?;
-7221        let open_result = self.open_nat_traversal_path(now, address);
-7222        let client_state = self.n0_nat_traversal.client_side_mut().expect("validated");
-7223        match open_result {
-7224            Ok(None) => Some(true),
-7225            Ok(Some((path_id, _remote))) => {
-7226                client_state.add_round_path_id(path_id);
-7227                Some(true)
-7228            }
-7229            Err(e) => {
-7230                client_state.report_in_continuation(id, e);
-7231                Some(false)
-7232            }
-7233        }
-7234    }
-7235
-7236    /// Whether the handshake is considered **confirmed**.
-7237    ///
-7238    /// <https://www.rfc-editor.org/rfc/rfc9001#section-4.1.2> defines a handshake to be
-7239    /// confirmed when you know the peer successfully received and successfully processed
-7240    /// your TLS Finished message.
-7241    ///
-7242    /// Implementation-wise this is the point at which the handshake crypto keys are
-7243    /// discarded. So we can use this to know if the handshake is confirmed.
-7244    fn is_handshake_confirmed(&self) -> bool {
-7245        !self.is_handshaking() && !self.crypto_state.has_keys(EncryptionLevel::Handshake)
-7246    }
+7149/// Hints when the caller identifies a network change.
+7150pub trait NetworkChangeHint: std::fmt::Debug + 'static {
+7151    /// Inform the connection if a path may recover after a network change.
+7152    ///
+7153    /// After network changes, paths may not be recoverable. In this case, waiting for the path to
+7154    /// become idle may take longer than what is desirable. If [`Self::is_path_recoverable`]
+7155    /// returns `false`, a multipath-enabled, client-side connection will establish a new path to
+7156    /// the same remote, closing the current one, instead of migrating the path.
+7157    ///
+7158    /// Paths that are deemed recoverable will simply be sent a PING for a liveness check.
+7159    fn is_path_recoverable(&self, path_id: PathId, network_path: FourTuple) -> bool;
+7160}
+7161
+7162/// Return value for [`Connection::poll_transmit_path_space`].
+7163#[derive(Debug)]
+7164enum PollPathSpaceStatus {
+7165    /// Nothing to send in the space, nothing was written into the [`TransmitBuf`].
+7166    NothingToSend {
+7167        /// If true there was data to send but congestion control did not allow so.
+7168        congestion_blocked: bool,
+7169    },
+7170    /// One or more packets have been written into the [`TransmitBuf`].
+7171    WrotePacket {
+7172        /// The highest packet number.
+7173        last_packet_number: u64,
+7174        /// Whether to pad an already started datagram in the next packet.
+7175        ///
+7176        /// When packets in Initial, 0-RTT or Handshake packet do not fill the entire
+7177        /// datagram they may decide to coalesce with the next packet from a higher
+7178        /// encryption level on the same path. But the earlier packet may require specific
+7179        /// size requirements for the datagram they are sent in.
+7180        ///
+7181        /// If a space did not complete the datagram, they use this to request the correct
+7182        /// padding in the final packet of the datagram so that the final datagram will have
+7183        /// the correct size.
+7184        ///
+7185        /// If a space did fill an entire datagram, it leaves this to the default of
+7186        /// [`PadDatagram::No`].
+7187        pad_datagram: PadDatagram,
+7188    },
+7189    /// Send the contents of the transmit immediately.
+7190    ///
+7191    /// Packets were written and the GSO batch must end now, regardless from whether higher
+7192    /// spaces still have frames to write. This is used when the last datagram written would
+7193    /// require too much padding to continue a GSO batch, which would waste space on the
+7194    /// wire.
+7195    Send {
+7196        /// The highest packet number written into the transmit.
+7197        last_packet_number: u64,
+7198    },
+7199}
+7200
+7201/// Information used to decide what frames to schedule into which packets.
+7202///
+7203/// Primarily used by [`Connection::poll_transmit_on_path`] and the functions that help
+7204/// building packets for it: [`Connection::poll_transmit_path_space`] and
+7205/// [`Connection::populate_packet`].
+7206#[derive(Debug, Copy, Clone)]
+7207struct PathSchedulingInfo {
+7208    /// Whether the path is abandoned.
+7209    ///
+7210    /// Note that a path that is abandoned but still has CIDs can still send a packet. After
+7211    /// sending that packet the CIDs issued by the remote have to be considered retired as
+7212    /// well.
+7213    is_abandoned: bool,
+7214    /// Whether the path may send [`SpaceKind::Data`] frames.
+7215    ///
+7216    /// Some paths should only send frames from [`SendableFrames::space_specific`]. All other
+7217    /// frames are essentially frames that can be sent on any [`SpaceKind::Data`] space. For
+7218    /// those we want to respect packet scheduling rules however.
+7219    ///
+7220    /// Roughly speaking data frames are only sent on spaces that have CIDs, are not
+7221    /// abandoned and have no *better* spaces. However see to comments where this is
+7222    /// populated for the exact packet scheduling implementation.
+7223    ///
+7224    /// This essentially marks this paths as the best validated space ID. Except during
+7225    /// the handshake in which case it does not need to be validated. Several paths could be
+7226    /// equally good and all have this set to `true`, in that case packet scheduling can
+7227    /// choose which path to use. Currently it chooses the lowest path that is not
+7228    /// congestion blocked.
+7229    ///
+7230    /// Note that once in the closed or draining states this will never be true.
+7231    may_send_data: bool,
+7232    /// Whether the path may send a CONNECTION_CLOSE frame.
+7233    ///
+7234    /// This essentially marks this path as the best validated space ID with a fallback
+7235    /// to unvalidated spaces if there are no validated spaces. Like for
+7236    /// [`Self::may_send_data`] other paths could be equally good.
+7237    may_send_close: bool,
+7238    may_self_abandon: bool,
+7239}
+7240
+7241#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+7242enum PathBlocked {
+7243    No,
+7244    AntiAmplification,
+7245    Congestion,
+7246    Pacing,
 7247}
 7248
-7249impl fmt::Debug for Connection {
-7250    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-7251        f.debug_struct("Connection")
-7252            .field("handshake_cid", &self.handshake_cid)
-7253            .finish()
-7254    }
-7255}
-7256
-7257/// Hints when the caller identifies a network change.
-7258pub trait NetworkChangeHint: std::fmt::Debug + 'static {
-7259    /// Inform the connection if a path may recover after a network change.
-7260    ///
-7261    /// After network changes, paths may not be recoverable. In this case, waiting for the path to
-7262    /// become idle may take longer than what is desirable. If [`Self::is_path_recoverable`]
-7263    /// returns `false`, a multipath-enabled, client-side connection will establish a new path to
-7264    /// the same remote, closing the current one, instead of migrating the path.
-7265    ///
-7266    /// Paths that are deemed recoverable will simply be sent a PING for a liveness check.
-7267    fn is_path_recoverable(&self, path_id: PathId, network_path: FourTuple) -> bool;
-7268}
-7269
-7270/// Return value for [`Connection::poll_transmit_path_space`].
-7271#[derive(Debug)]
-7272enum PollPathSpaceStatus {
-7273    /// Nothing to send in the space, nothing was written into the [`TransmitBuf`].
-7274    NothingToSend {
-7275        /// If true there was data to send but congestion control did not allow so.
-7276        congestion_blocked: bool,
-7277    },
-7278    /// One or more packets have been written into the [`TransmitBuf`].
-7279    WrotePacket {
-7280        /// The highest packet number.
-7281        last_packet_number: u64,
-7282        /// Whether to pad an already started datagram in the next packet.
-7283        ///
-7284        /// When packets in Initial, 0-RTT or Handshake packet do not fill the entire
-7285        /// datagram they may decide to coalesce with the next packet from a higher
-7286        /// encryption level on the same path. But the earlier packet may require specific
-7287        /// size requirements for the datagram they are sent in.
-7288        ///
-7289        /// If a space did not complete the datagram, they use this to request the correct
-7290        /// padding in the final packet of the datagram so that the final datagram will have
-7291        /// the correct size.
-7292        ///
-7293        /// If a space did fill an entire datagram, it leaves this to the default of
-7294        /// [`PadDatagram::No`].
-7295        pad_datagram: PadDatagram,
-7296    },
-7297    /// Send the contents of the transmit immediately.
-7298    ///
-7299    /// Packets were written and the GSO batch must end now, regardless from whether higher
-7300    /// spaces still have frames to write. This is used when the last datagram written would
-7301    /// require too much padding to continue a GSO batch, which would waste space on the
-7302    /// wire.
-7303    Send {
-7304        /// The highest packet number written into the transmit.
-7305        last_packet_number: u64,
-7306    },
-7307}
-7308
-7309/// Information used to decide what frames to schedule into which packets.
-7310///
-7311/// Primarily used by [`Connection::poll_transmit_on_path`] and the functions that help
-7312/// building packets for it: [`Connection::poll_transmit_path_space`] and
-7313/// [`Connection::populate_packet`].
-7314#[derive(Debug, Copy, Clone)]
-7315struct PathSchedulingInfo {
-7316    /// Whether the path is abandoned.
-7317    ///
-7318    /// Note that a path that is abandoned but still has CIDs can still send a packet. After
-7319    /// sending that packet the CIDs issued by the remote have to be considered retired as
-7320    /// well.
-7321    is_abandoned: bool,
-7322    /// Whether the path may send [`SpaceKind::Data`] frames.
-7323    ///
-7324    /// Some paths should only send frames from [`SendableFrames::space_specific`]. All other
-7325    /// frames are essentially frames that can be sent on any [`SpaceKind::Data`] space. For
-7326    /// those we want to respect packet scheduling rules however.
-7327    ///
-7328    /// Roughly speaking data frames are only sent on spaces that have CIDs, are not
-7329    /// abandoned and have no *better* spaces. However see to comments where this is
-7330    /// populated for the exact packet scheduling implementation.
-7331    ///
-7332    /// This essentially marks this paths as the best validated space ID. Except during
-7333    /// the handshake in which case it does not need to be validated. Several paths could be
-7334    /// equally good and all have this set to `true`, in that case packet scheduling can
-7335    /// choose which path to use. Currently it chooses the lowest path that is not
-7336    /// congestion blocked.
-7337    ///
-7338    /// Note that once in the closed or draining states this will never be true.
-7339    may_send_data: bool,
-7340    /// Whether the path may send a CONNECTION_CLOSE frame.
-7341    ///
-7342    /// This essentially marks this path as the best validated space ID with a fallback
-7343    /// to unvalidated spaces if there are no validated spaces. Like for
-7344    /// [`Self::may_send_data`] other paths could be equally good.
-7345    may_send_close: bool,
-7346    may_self_abandon: bool,
-7347}
-7348
-7349#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-7350enum PathBlocked {
-7351    No,
-7352    AntiAmplification,
-7353    Congestion,
-7354    Pacing,
-7355}
-7356
-7357/// Fields of `Connection` specific to it being client-side or server-side
-7358enum ConnectionSide {
-7359    Client {
-7360        /// Sent in every outgoing Initial packet. Always empty after Initial keys are discarded
-7361        token: Bytes,
-7362        token_store: Arc<dyn TokenStore>,
-7363        server_name: String,
-7364    },
-7365    Server {
-7366        server_config: Arc<ServerConfig>,
-7367    },
+7249/// Fields of `Connection` specific to it being client-side or server-side
+7250enum ConnectionSide {
+7251    Client {
+7252        /// Sent in every outgoing Initial packet. Always empty after Initial keys are discarded
+7253        token: Bytes,
+7254        token_store: Arc<dyn TokenStore>,
+7255        server_name: String,
+7256    },
+7257    Server {
+7258        server_config: Arc<ServerConfig>,
+7259    },
+7260}
+7261
+7262impl ConnectionSide {
+7263    fn is_client(&self) -> bool {
+7264        self.side().is_client()
+7265    }
+7266
+7267    fn is_server(&self) -> bool {
+7268        self.side().is_server()
+7269    }
+7270
+7271    fn side(&self) -> Side {
+7272        match *self {
+7273            Self::Client { .. } => Side::Client,
+7274            Self::Server { .. } => Side::Server,
+7275        }
+7276    }
+7277}
+7278
+7279impl From<SideArgs> for ConnectionSide {
+7280    fn from(side: SideArgs) -> Self {
+7281        match side {
+7282            SideArgs::Client {
+7283                token_store,
+7284                server_name,
+7285            } => Self::Client {
+7286                token: token_store.take(&server_name).unwrap_or_default(),
+7287                token_store,
+7288                server_name,
+7289            },
+7290            SideArgs::Server {
+7291                server_config,
+7292                pref_addr_cid: _,
+7293                path_validated: _,
+7294            } => Self::Server { server_config },
+7295        }
+7296    }
+7297}
+7298
+7299/// Parameters to `Connection::new` specific to it being client-side or server-side
+7300pub(crate) enum SideArgs {
+7301    Client {
+7302        token_store: Arc<dyn TokenStore>,
+7303        server_name: String,
+7304    },
+7305    Server {
+7306        server_config: Arc<ServerConfig>,
+7307        pref_addr_cid: Option<ConnectionId>,
+7308        path_validated: bool,
+7309    },
+7310}
+7311
+7312impl SideArgs {
+7313    pub(crate) fn pref_addr_cid(&self) -> Option<ConnectionId> {
+7314        match *self {
+7315            Self::Client { .. } => None,
+7316            Self::Server { pref_addr_cid, .. } => pref_addr_cid,
+7317        }
+7318    }
+7319
+7320    pub(crate) fn path_validated(&self) -> bool {
+7321        match *self {
+7322            Self::Client { .. } => true,
+7323            Self::Server { path_validated, .. } => path_validated,
+7324        }
+7325    }
+7326
+7327    pub(crate) fn side(&self) -> Side {
+7328        match *self {
+7329            Self::Client { .. } => Side::Client,
+7330            Self::Server { .. } => Side::Server,
+7331        }
+7332    }
+7333}
+7334
+7335/// Reasons why a connection might be lost
+7336#[derive(Debug, Error, Clone, PartialEq, Eq)]
+7337pub enum ConnectionError {
+7338    /// The peer doesn't implement any supported version
+7339    #[error("peer doesn't implement any supported version")]
+7340    VersionMismatch,
+7341    /// The peer violated the QUIC specification as understood by this implementation
+7342    #[error(transparent)]
+7343    TransportError(#[from] TransportError),
+7344    /// The peer's QUIC stack aborted the connection automatically
+7345    #[error("aborted by peer: {0}")]
+7346    ConnectionClosed(frame::ConnectionClose),
+7347    /// The peer closed the connection
+7348    #[error("closed by peer: {0}")]
+7349    ApplicationClosed(frame::ApplicationClose),
+7350    /// The peer is unable to continue processing this connection, usually due to having restarted
+7351    #[error("reset by peer")]
+7352    Reset,
+7353    /// Communication with the peer has lapsed for longer than the negotiated idle timeout
+7354    ///
+7355    /// If neither side is sending keep-alives, a connection will time out after a long enough idle
+7356    /// period even if the peer is still reachable. See also [`TransportConfig::max_idle_timeout()`]
+7357    /// and [`TransportConfig::keep_alive_interval()`].
+7358    #[error("timed out")]
+7359    TimedOut,
+7360    /// The local application closed the connection
+7361    #[error("closed")]
+7362    LocallyClosed,
+7363    /// The connection could not be created because not enough of the CID space is available
+7364    ///
+7365    /// Try using longer connection IDs.
+7366    #[error("CIDs exhausted")]
+7367    CidsExhausted,
 7368}
 7369
-7370impl ConnectionSide {
-7371    fn is_client(&self) -> bool {
-7372        self.side().is_client()
-7373    }
-7374
-7375    fn is_server(&self) -> bool {
-7376        self.side().is_server()
-7377    }
+7370impl From<Close> for ConnectionError {
+7371    fn from(x: Close) -> Self {
+7372        match x {
+7373            Close::Connection(reason) => Self::ConnectionClosed(reason),
+7374            Close::Application(reason) => Self::ApplicationClosed(reason),
+7375        }
+7376    }
+7377}
 7378
-7379    fn side(&self) -> Side {
-7380        match *self {
-7381            Self::Client { .. } => Side::Client,
-7382            Self::Server { .. } => Side::Server,
-7383        }
-7384    }
-7385}
-7386
-7387impl From<SideArgs> for ConnectionSide {
-7388    fn from(side: SideArgs) -> Self {
-7389        match side {
-7390            SideArgs::Client {
-7391                token_store,
-7392                server_name,
-7393            } => Self::Client {
-7394                token: token_store.take(&server_name).unwrap_or_default(),
-7395                token_store,
-7396                server_name,
-7397            },
-7398            SideArgs::Server {
-7399                server_config,
-7400                pref_addr_cid: _,
-7401                path_validated: _,
-7402            } => Self::Server { server_config },
-7403        }
-7404    }
-7405}
-7406
-7407/// Parameters to `Connection::new` specific to it being client-side or server-side
-7408pub(crate) enum SideArgs {
-7409    Client {
-7410        token_store: Arc<dyn TokenStore>,
-7411        server_name: String,
-7412    },
-7413    Server {
-7414        server_config: Arc<ServerConfig>,
-7415        pref_addr_cid: Option<ConnectionId>,
-7416        path_validated: bool,
-7417    },
-7418}
-7419
-7420impl SideArgs {
-7421    pub(crate) fn pref_addr_cid(&self) -> Option<ConnectionId> {
-7422        match *self {
-7423            Self::Client { .. } => None,
-7424            Self::Server { pref_addr_cid, .. } => pref_addr_cid,
-7425        }
-7426    }
-7427
-7428    pub(crate) fn path_validated(&self) -> bool {
-7429        match *self {
-7430            Self::Client { .. } => true,
-7431            Self::Server { path_validated, .. } => path_validated,
-7432        }
-7433    }
+7379// For compatibility with API consumers
+7380impl From<ConnectionError> for io::Error {
+7381    fn from(x: ConnectionError) -> Self {
+7382        use ConnectionError::*;
+7383        let kind = match x {
+7384            TimedOut => io::ErrorKind::TimedOut,
+7385            Reset => io::ErrorKind::ConnectionReset,
+7386            ApplicationClosed(_) | ConnectionClosed(_) => io::ErrorKind::ConnectionAborted,
+7387            TransportError(_) | VersionMismatch | LocallyClosed | CidsExhausted => {
+7388                io::ErrorKind::Other
+7389            }
+7390        };
+7391        Self::new(kind, x)
+7392    }
+7393}
+7394
+7395/// Errors that might trigger a path being closed
+7396// TODO(@divma): maybe needs to be reworked based on what we want to do with the public API
+7397#[derive(Debug, Error, PartialEq, Eq, Clone, Copy)]
+7398pub enum PathError {
+7399    /// The extension was not negotiated with the peer
+7400    #[error("multipath extension not negotiated")]
+7401    MultipathNotNegotiated,
+7402    /// Paths can only be opened client-side
+7403    #[error("the server side may not open a path")]
+7404    ServerSideNotAllowed,
+7405    /// Current limits do not allow us to open more paths
+7406    #[error("maximum number of concurrent paths reached")]
+7407    MaxPathIdReached,
+7408    /// No remote CIDs available to open a new path
+7409    #[error("remoted CIDs exhausted")]
+7410    RemoteCidsExhausted,
+7411    /// Path could not be validated and will be abandoned
+7412    #[error("path validation failed")]
+7413    ValidationFailed,
+7414    /// The remote address for the path is not supported by the endpoint
+7415    #[error("invalid remote address")]
+7416    InvalidRemoteAddress(SocketAddr),
+7417}
+7418
+7419/// Errors triggered when abandoning a path
+7420#[derive(Debug, Error, Clone, Eq, PartialEq)]
+7421pub enum ClosePathError {
+7422    /// Multipath is not negotiated
+7423    #[error("Multipath extension not negotiated")]
+7424    MultipathNotNegotiated,
+7425    /// The path is already closed or was never opened
+7426    #[error("closed path")]
+7427    ClosedPath,
+7428    /// Cannot close the last remaining open path via the local API.
+7429    ///
+7430    /// Use [`Connection::close`] to end the connection instead.
+7431    #[error("last open path")]
+7432    LastOpenPath,
+7433}
 7434
-7435    pub(crate) fn side(&self) -> Side {
-7436        match *self {
-7437            Self::Client { .. } => Side::Client,
-7438            Self::Server { .. } => Side::Server,
-7439        }
-7440    }
-7441}
-7442
-7443/// Reasons why a connection might be lost
-7444#[derive(Debug, Error, Clone, PartialEq, Eq)]
-7445pub enum ConnectionError {
-7446    /// The peer doesn't implement any supported version
-7447    #[error("peer doesn't implement any supported version")]
-7448    VersionMismatch,
-7449    /// The peer violated the QUIC specification as understood by this implementation
-7450    #[error(transparent)]
-7451    TransportError(#[from] TransportError),
-7452    /// The peer's QUIC stack aborted the connection automatically
-7453    #[error("aborted by peer: {0}")]
-7454    ConnectionClosed(frame::ConnectionClose),
-7455    /// The peer closed the connection
-7456    #[error("closed by peer: {0}")]
-7457    ApplicationClosed(frame::ApplicationClose),
-7458    /// The peer is unable to continue processing this connection, usually due to having restarted
-7459    #[error("reset by peer")]
-7460    Reset,
-7461    /// Communication with the peer has lapsed for longer than the negotiated idle timeout
-7462    ///
-7463    /// If neither side is sending keep-alives, a connection will time out after a long enough idle
-7464    /// period even if the peer is still reachable. See also [`TransportConfig::max_idle_timeout()`]
-7465    /// and [`TransportConfig::keep_alive_interval()`].
-7466    #[error("timed out")]
-7467    TimedOut,
-7468    /// The local application closed the connection
-7469    #[error("closed")]
-7470    LocallyClosed,
-7471    /// The connection could not be created because not enough of the CID space is available
-7472    ///
-7473    /// Try using longer connection IDs.
-7474    #[error("CIDs exhausted")]
-7475    CidsExhausted,
-7476}
-7477
-7478impl From<Close> for ConnectionError {
-7479    fn from(x: Close) -> Self {
-7480        match x {
-7481            Close::Connection(reason) => Self::ConnectionClosed(reason),
-7482            Close::Application(reason) => Self::ApplicationClosed(reason),
-7483        }
-7484    }
-7485}
-7486
-7487// For compatibility with API consumers
-7488impl From<ConnectionError> for io::Error {
-7489    fn from(x: ConnectionError) -> Self {
-7490        use ConnectionError::*;
-7491        let kind = match x {
-7492            TimedOut => io::ErrorKind::TimedOut,
-7493            Reset => io::ErrorKind::ConnectionReset,
-7494            ApplicationClosed(_) | ConnectionClosed(_) => io::ErrorKind::ConnectionAborted,
-7495            TransportError(_) | VersionMismatch | LocallyClosed | CidsExhausted => {
-7496                io::ErrorKind::Other
-7497            }
-7498        };
-7499        Self::new(kind, x)
-7500    }
-7501}
-7502
-7503/// Errors that might trigger a path being closed
-7504// TODO(@divma): maybe needs to be reworked based on what we want to do with the public API
-7505#[derive(Debug, Error, PartialEq, Eq, Clone, Copy)]
-7506pub enum PathError {
-7507    /// The extension was not negotiated with the peer
-7508    #[error("multipath extension not negotiated")]
-7509    MultipathNotNegotiated,
-7510    /// Paths can only be opened client-side
-7511    #[error("the server side may not open a path")]
-7512    ServerSideNotAllowed,
-7513    /// Current limits do not allow us to open more paths
-7514    #[error("maximum number of concurrent paths reached")]
-7515    MaxPathIdReached,
-7516    /// No remote CIDs available to open a new path
-7517    #[error("remoted CIDs exhausted")]
-7518    RemoteCidsExhausted,
-7519    /// Path could not be validated and will be abandoned
-7520    #[error("path validation failed")]
-7521    ValidationFailed,
-7522    /// The remote address for the path is not supported by the endpoint
-7523    #[error("invalid remote address")]
-7524    InvalidRemoteAddress(SocketAddr),
-7525}
-7526
-7527/// Errors triggered when abandoning a path
-7528#[derive(Debug, Error, Clone, Eq, PartialEq)]
-7529pub enum ClosePathError {
-7530    /// Multipath is not negotiated
-7531    #[error("Multipath extension not negotiated")]
-7532    MultipathNotNegotiated,
-7533    /// The path is already closed or was never opened
-7534    #[error("closed path")]
-7535    ClosedPath,
-7536    /// Cannot close the last remaining open path via the local API.
-7537    ///
-7538    /// Use [`Connection::close`] to end the connection instead.
-7539    #[error("last open path")]
-7540    LastOpenPath,
-7541}
-7542
-7543/// Error when the multipath extension was not negotiated, but attempted to be used.
-7544#[derive(Debug, Error, Clone, Copy)]
-7545#[error("Multipath extension not negotiated")]
-7546pub struct MultipathNotNegotiated {
-7547    _private: (),
-7548}
-7549
-7550/// Events of interest to the application
-7551#[derive(Debug)]
-7552pub enum Event {
-7553    /// The connection's handshake data is ready
-7554    HandshakeDataReady,
-7555    /// The connection was successfully established
-7556    Connected,
-7557    /// The TLS handshake was confirmed
-7558    HandshakeConfirmed,
-7559    /// The connection was lost
-7560    ///
-7561    /// Emitted when the connection is closed due to an error, a timeout, or the peer closing it.
-7562    /// This is **not** emitted when the local application closes the connection via
-7563    /// [`Connection::close()`](crate::Connection::close). In that case, pending operations will
-7564    /// fail with [`ConnectionError::LocallyClosed`].
-7565    ConnectionLost {
-7566        /// Reason that the connection was closed
-7567        reason: ConnectionError,
-7568    },
-7569    /// Stream events
-7570    Stream(StreamEvent),
-7571    /// One or more application datagrams have been received
-7572    DatagramReceived,
-7573    /// One or more application datagrams have been sent after blocking
-7574    DatagramsUnblocked,
-7575    /// (Multi)Path events
-7576    Path(PathEvent),
-7577    /// n0's nat traversal events
-7578    NatTraversal(n0_nat_traversal::Event),
-7579}
-7580
-7581impl From<PathEvent> for Event {
-7582    fn from(source: PathEvent) -> Self {
-7583        Self::Path(source)
-7584    }
-7585}
-7586
-7587fn get_max_ack_delay(params: &TransportParameters) -> Duration {
-7588    Duration::from_micros(params.max_ack_delay.0 * 1000)
-7589}
-7590
-7591/// Prevents overflow and improves behavior in extreme circumstances.
-7592const MAX_BACKOFF_EXPONENT: u32 = 16;
-7593
-7594/// The max interval between successive tail-loss probes.
-7595///
-7596/// This is the "normal" value we use.
-7597const MAX_PTO_INTERVAL: Duration = Duration::from_secs(2);
-7598
-7599/// The idle time, below which we use the shorter [`MAX_PTO_FAST_INTERVAL`].
-7600const MIN_IDLE_FOR_FAST_PTO: Duration = Duration::from_secs(25);
-7601
-7602/// The max interval between successive tail-loss probes with short idle times.
-7603///
-7604/// If the path or connection idle time is less than [`MIN_IDLE_FOR_FAST_PTO`] then we use
-7605/// this value to ensure we have plenty of retransmits before we reach the idle time.
-7606const MAX_PTO_FAST_INTERVAL: Duration = Duration::from_secs(1);
-7607
-7608/// The RTT threshold above which we cap the PTO interval to 1.5 * smoothed_rtt
-7609///
-7610/// This is RTT time above which 1.5 * RTT > [`MAX_PTO_INTERVAL`], for these links we want
-7611/// to extend the interval between tail-loss probes to not fill the entire pipe with them.
-7612const SLOW_RTT_THRESHOLD: Duration =
-7613    Duration::from_millis((MAX_PTO_INTERVAL.as_millis() as u64 * 2) / 3);
-7614
-7615/// Minimal remaining size to allow packet coalescing, excluding cryptographic tag
-7616///
-7617/// This must be at least as large as the header for a well-formed empty packet to be coalesced,
-7618/// plus some space for frames. We only care about handshake headers because short header packets
-7619/// necessarily have smaller headers, and initial packets are only ever the first packet in a
-7620/// datagram (because we coalesce in ascending packet space order and the only reason to split a
-7621/// packet is when packet space changes).
-7622const MIN_PACKET_SPACE: usize = MAX_HANDSHAKE_OR_0RTT_HEADER_SIZE + 32;
-7623
-7624/// Largest amount of space that could be occupied by a Handshake or 0-RTT packet's header
+7435/// Error when the multipath extension was not negotiated, but attempted to be used.
+7436#[derive(Debug, Error, Clone, Copy)]
+7437#[error("Multipath extension not negotiated")]
+7438pub struct MultipathNotNegotiated {
+7439    _private: (),
+7440}
+7441
+7442/// Events of interest to the application
+7443#[derive(Debug)]
+7444pub enum Event {
+7445    /// The connection's handshake data is ready
+7446    HandshakeDataReady,
+7447    /// The connection was successfully established
+7448    Connected,
+7449    /// The TLS handshake was confirmed
+7450    HandshakeConfirmed,
+7451    /// The connection was lost
+7452    ///
+7453    /// Emitted when the connection is closed due to an error, a timeout, or the peer closing it.
+7454    /// This is **not** emitted when the local application closes the connection via
+7455    /// [`Connection::close()`](crate::Connection::close). In that case, pending operations will
+7456    /// fail with [`ConnectionError::LocallyClosed`].
+7457    ConnectionLost {
+7458        /// Reason that the connection was closed
+7459        reason: ConnectionError,
+7460    },
+7461    /// Stream events
+7462    Stream(StreamEvent),
+7463    /// One or more application datagrams have been received
+7464    DatagramReceived,
+7465    /// One or more application datagrams have been sent after blocking
+7466    DatagramsUnblocked,
+7467    /// (Multi)Path events
+7468    Path(PathEvent),
+7469    /// n0's nat traversal events
+7470    NatTraversal(n0_nat_traversal::Event),
+7471}
+7472
+7473impl From<PathEvent> for Event {
+7474    fn from(source: PathEvent) -> Self {
+7475        Self::Path(source)
+7476    }
+7477}
+7478
+7479fn get_max_ack_delay(params: &TransportParameters) -> Duration {
+7480    Duration::from_micros(params.max_ack_delay.0 * 1000)
+7481}
+7482
+7483/// Prevents overflow and improves behavior in extreme circumstances.
+7484const MAX_BACKOFF_EXPONENT: u32 = 16;
+7485
+7486/// The max interval between successive tail-loss probes.
+7487///
+7488/// This is the "normal" value we use.
+7489const MAX_PTO_INTERVAL: Duration = Duration::from_secs(2);
+7490
+7491/// The idle time, below which we use the shorter [`MAX_PTO_FAST_INTERVAL`].
+7492const MIN_IDLE_FOR_FAST_PTO: Duration = Duration::from_secs(25);
+7493
+7494/// The max interval between successive tail-loss probes with short idle times.
+7495///
+7496/// If the path or connection idle time is less than [`MIN_IDLE_FOR_FAST_PTO`] then we use
+7497/// this value to ensure we have plenty of retransmits before we reach the idle time.
+7498const MAX_PTO_FAST_INTERVAL: Duration = Duration::from_secs(1);
+7499
+7500/// The RTT threshold above which we cap the PTO interval to 1.5 * smoothed_rtt
+7501///
+7502/// This is RTT time above which 1.5 * RTT > [`MAX_PTO_INTERVAL`], for these links we want
+7503/// to extend the interval between tail-loss probes to not fill the entire pipe with them.
+7504const SLOW_RTT_THRESHOLD: Duration =
+7505    Duration::from_millis((MAX_PTO_INTERVAL.as_millis() as u64 * 2) / 3);
+7506
+7507/// Minimal remaining size to allow packet coalescing, excluding cryptographic tag
+7508///
+7509/// This must be at least as large as the header for a well-formed empty packet to be coalesced,
+7510/// plus some space for frames. We only care about handshake headers because short header packets
+7511/// necessarily have smaller headers, and initial packets are only ever the first packet in a
+7512/// datagram (because we coalesce in ascending packet space order and the only reason to split a
+7513/// packet is when packet space changes).
+7514const MIN_PACKET_SPACE: usize = MAX_HANDSHAKE_OR_0RTT_HEADER_SIZE + 32;
+7515
+7516/// Largest amount of space that could be occupied by a Handshake or 0-RTT packet's header
+7517///
+7518/// Excludes packet-type-specific fields such as packet number or Initial token
+7519// https://www.rfc-editor.org/rfc/rfc9000.html#name-0-rtt: flags + version + dcid len + dcid +
+7520// scid len + scid + length + pn
+7521const MAX_HANDSHAKE_OR_0RTT_HEADER_SIZE: usize =
+7522    1 + 4 + 1 + MAX_CID_SIZE + 1 + MAX_CID_SIZE + VarInt::from_u32(u16::MAX as u32).size() + 4;
+7523
+7524#[derive(Default)]
+7525struct SentFrames {
+7526    retransmits: ThinRetransmits,
+7527    /// The packet number of the largest acknowledged packet for each path
+7528    largest_acked: FxHashMap<PathId, u64>,
+7529    stream_frames: StreamMetaVec,
+7530    /// Whether the packet contains non-retransmittable frames (like datagrams)
+7531    non_retransmits: bool,
+7532    /// If the datagram containing these frames should be padded to the min MTU
+7533    requires_padding: bool,
+7534}
+7535
+7536impl SentFrames {
+7537    /// Returns whether the packet contains only ACKs
+7538    fn is_ack_only(&self, streams: &StreamsState) -> bool {
+7539        !self.largest_acked.is_empty()
+7540            && !self.non_retransmits
+7541            && self.stream_frames.is_empty()
+7542            && self.retransmits.is_empty(streams)
+7543    }
+7544
+7545    fn retransmits_mut(&mut self) -> &mut Retransmits {
+7546        self.retransmits.get_or_create()
+7547    }
+7548
+7549    fn record_sent_frame(&mut self, frame: frame::EncodableFrame<'_>) {
+7550        use frame::EncodableFrame::*;
+7551        match frame {
+7552            PathAck(path_ack_encoder) => {
+7553                if let Some(max) = path_ack_encoder.ranges.max() {
+7554                    self.largest_acked.insert(path_ack_encoder.path_id, max);
+7555                }
+7556            }
+7557            Ack(ack_encoder) => {
+7558                if let Some(max) = ack_encoder.ranges.max() {
+7559                    self.largest_acked.insert(PathId::ZERO, max);
+7560                }
+7561            }
+7562            Close(_) => { /* non retransmittable, but after this we don't really care */ }
+7563            PathResponse(_) => self.non_retransmits = true,
+7564            HandshakeDone(_) => self.retransmits_mut().handshake_done = true,
+7565            ReachOut(frame) => self.retransmits_mut().reach_out.push(frame),
+7566            ObservedAddr(_) => self.retransmits_mut().observed_addr = true,
+7567            Ping(_) => self.non_retransmits = true,
+7568            ImmediateAck(_) => self.non_retransmits = true,
+7569            AckFrequency(_) => self.retransmits_mut().ack_frequency = true,
+7570            PathChallenge(_) => self.non_retransmits = true,
+7571            Crypto(crypto) => self.retransmits_mut().crypto.push_back(crypto),
+7572            PathAbandon(path_abandon) => {
+7573                self.retransmits_mut()
+7574                    .path_abandon
+7575                    .entry(path_abandon.path_id)
+7576                    .or_insert(path_abandon.error_code);
+7577            }
+7578            PathStatusAvailable(frame::PathStatusAvailable { path_id, .. })
+7579            | PathStatusBackup(frame::PathStatusBackup { path_id, .. }) => {
+7580                self.retransmits_mut().path_status.insert(path_id);
+7581            }
+7582            MaxPathId(_) => self.retransmits_mut().max_path_id = true,
+7583            PathsBlocked(_) => self.retransmits_mut().paths_blocked = true,
+7584            PathCidsBlocked(path_cids_blocked) => {
+7585                self.retransmits_mut()
+7586                    .path_cids_blocked
+7587                    .insert(path_cids_blocked.path_id);
+7588            }
+7589            ResetStream(reset) => self
+7590                .retransmits_mut()
+7591                .reset_stream
+7592                .push((reset.id, reset.error_code)),
+7593            StopSending(stop_sending) => self.retransmits_mut().stop_sending.push(stop_sending),
+7594            NewConnectionId(new_cid) => self.retransmits_mut().new_cids.push(new_cid.issued()),
+7595            RetireConnectionId(retire_cid) => self
+7596                .retransmits_mut()
+7597                .retire_cids
+7598                .push((retire_cid.path_id.unwrap_or_default(), retire_cid.sequence)),
+7599            Datagram(_) => self.non_retransmits = true,
+7600            NewToken(_) => {}
+7601            AddAddress(add_address) => {
+7602                self.retransmits_mut().add_address.insert(add_address);
+7603            }
+7604            RemoveAddress(remove_address) => {
+7605                self.retransmits_mut().remove_address.insert(remove_address);
+7606            }
+7607            StreamMeta(stream_meta_encoder) => self.stream_frames.push(stream_meta_encoder.meta),
+7608            MaxData(_) => self.retransmits_mut().max_data = true,
+7609            MaxStreamData(max) => {
+7610                self.retransmits_mut().max_stream_data.insert(max.id);
+7611            }
+7612            MaxStreams(max_streams) => {
+7613                self.retransmits_mut().max_stream_id[max_streams.dir as usize] = true
+7614            }
+7615            StreamsBlocked(streams_blocked) => {
+7616                self.retransmits_mut().streams_blocked[streams_blocked.dir as usize] = true
+7617            }
+7618        }
+7619    }
+7620}
+7621
+7622/// Compute the negotiated idle timeout based on local and remote max_idle_timeout transport parameters.
+7623///
+7624/// According to the definition of max_idle_timeout, a value of `0` means the timeout is disabled; see <https://www.rfc-editor.org/rfc/rfc9000#section-18.2-4.4.1.>
 7625///
-7626/// Excludes packet-type-specific fields such as packet number or Initial token
-7627// https://www.rfc-editor.org/rfc/rfc9000.html#name-0-rtt: flags + version + dcid len + dcid +
-7628// scid len + scid + length + pn
-7629const MAX_HANDSHAKE_OR_0RTT_HEADER_SIZE: usize =
-7630    1 + 4 + 1 + MAX_CID_SIZE + 1 + MAX_CID_SIZE + VarInt::from_u32(u16::MAX as u32).size() + 4;
-7631
-7632#[derive(Default)]
-7633struct SentFrames {
-7634    retransmits: ThinRetransmits,
-7635    /// The packet number of the largest acknowledged packet for each path
-7636    largest_acked: FxHashMap<PathId, u64>,
-7637    stream_frames: StreamMetaVec,
-7638    /// Whether the packet contains non-retransmittable frames (like datagrams)
-7639    non_retransmits: bool,
-7640    /// If the datagram containing these frames should be padded to the min MTU
-7641    requires_padding: bool,
-7642}
-7643
-7644impl SentFrames {
-7645    /// Returns whether the packet contains only ACKs
-7646    fn is_ack_only(&self, streams: &StreamsState) -> bool {
-7647        !self.largest_acked.is_empty()
-7648            && !self.non_retransmits
-7649            && self.stream_frames.is_empty()
-7650            && self.retransmits.is_empty(streams)
-7651    }
-7652
-7653    fn retransmits_mut(&mut self) -> &mut Retransmits {
-7654        self.retransmits.get_or_create()
-7655    }
-7656
-7657    fn record_sent_frame(&mut self, frame: frame::EncodableFrame<'_>) {
-7658        use frame::EncodableFrame::*;
-7659        match frame {
-7660            PathAck(path_ack_encoder) => {
-7661                if let Some(max) = path_ack_encoder.ranges.max() {
-7662                    self.largest_acked.insert(path_ack_encoder.path_id, max);
-7663                }
-7664            }
-7665            Ack(ack_encoder) => {
-7666                if let Some(max) = ack_encoder.ranges.max() {
-7667                    self.largest_acked.insert(PathId::ZERO, max);
-7668                }
-7669            }
-7670            Close(_) => { /* non retransmittable, but after this we don't really care */ }
-7671            PathResponse(_) => self.non_retransmits = true,
-7672            HandshakeDone(_) => self.retransmits_mut().handshake_done = true,
-7673            ReachOut(frame::ReachOut { round, ip, port }) => {
-7674                let (recorded_round, reach_outs) = self
-7675                    .retransmits_mut()
-7676                    .reach_out
-7677                    .get_or_insert_with(|| (round, FxHashSet::default()));
-7678                // Only record reach outs for the current round or a newer than the recorded one.
-7679                if *recorded_round == round {
-7680                    // Same round, simply append.
-7681                    reach_outs.insert((ip, port));
-7682                } else if *recorded_round < round {
-7683                    // New round.
-7684                    *recorded_round = round;
-7685                    reach_outs.drain();
-7686                    reach_outs.insert((ip, port));
-7687                } else {
-7688                    // ignore old reach out that was sent
-7689                }
-7690            }
-7691
-7692            ObservedAddr(_) => self.retransmits_mut().observed_addr = true,
-7693            Ping(_) => self.non_retransmits = true,
-7694            ImmediateAck(_) => self.non_retransmits = true,
-7695            AckFrequency(_) => self.retransmits_mut().ack_frequency = true,
-7696            PathChallenge(_) => self.non_retransmits = true,
-7697            Crypto(crypto) => self.retransmits_mut().crypto.push_back(crypto),
-7698            PathAbandon(path_abandon) => {
-7699                self.retransmits_mut()
-7700                    .path_abandon
-7701                    .entry(path_abandon.path_id)
-7702                    .or_insert(path_abandon.error_code);
-7703            }
-7704            PathStatusAvailable(frame::PathStatusAvailable { path_id, .. })
-7705            | PathStatusBackup(frame::PathStatusBackup { path_id, .. }) => {
-7706                self.retransmits_mut().path_status.insert(path_id);
-7707            }
-7708            MaxPathId(_) => self.retransmits_mut().max_path_id = true,
-7709            PathsBlocked(_) => self.retransmits_mut().paths_blocked = true,
-7710            PathCidsBlocked(path_cids_blocked) => {
-7711                self.retransmits_mut()
-7712                    .path_cids_blocked
-7713                    .insert(path_cids_blocked.path_id);
-7714            }
-7715            ResetStream(reset) => self
-7716                .retransmits_mut()
-7717                .reset_stream
-7718                .push((reset.id, reset.error_code)),
-7719            StopSending(stop_sending) => self.retransmits_mut().stop_sending.push(stop_sending),
-7720            NewConnectionId(new_cid) => self.retransmits_mut().new_cids.push(new_cid.issued()),
-7721            RetireConnectionId(retire_cid) => self
-7722                .retransmits_mut()
-7723                .retire_cids
-7724                .push((retire_cid.path_id.unwrap_or_default(), retire_cid.sequence)),
-7725            Datagram(_) => self.non_retransmits = true,
-7726            NewToken(_) => {}
-7727            AddAddress(add_address) => {
-7728                self.retransmits_mut().add_address.insert(add_address);
-7729            }
-7730            RemoveAddress(remove_address) => {
-7731                self.retransmits_mut().remove_address.insert(remove_address);
-7732            }
-7733            StreamMeta(stream_meta_encoder) => self.stream_frames.push(stream_meta_encoder.meta),
-7734            MaxData(_) => self.retransmits_mut().max_data = true,
-7735            MaxStreamData(max) => {
-7736                self.retransmits_mut().max_stream_data.insert(max.id);
-7737            }
-7738            MaxStreams(max_streams) => {
-7739                self.retransmits_mut().max_stream_id[max_streams.dir as usize] = true
-7740            }
-7741            StreamsBlocked(streams_blocked) => {
-7742                self.retransmits_mut().streams_blocked[streams_blocked.dir as usize] = true
-7743            }
-7744        }
-7745    }
-7746}
-7747
-7748/// Compute the negotiated idle timeout based on local and remote max_idle_timeout transport parameters.
-7749///
-7750/// According to the definition of max_idle_timeout, a value of `0` means the timeout is disabled; see <https://www.rfc-editor.org/rfc/rfc9000#section-18.2-4.4.1.>
-7751///
-7752/// According to the negotiation procedure, either the minimum of the timeouts or one specified is used as the negotiated value; see <https://www.rfc-editor.org/rfc/rfc9000#section-10.1-2.>
-7753///
-7754/// Returns the negotiated idle timeout as a `Duration`, or `None` when both endpoints have opted out of idle timeout.
-7755fn negotiate_max_idle_timeout(x: Option<VarInt>, y: Option<VarInt>) -> Option<Duration> {
-7756    match (x, y) {
-7757        (Some(VarInt(0)) | None, Some(VarInt(0)) | None) => None,
-7758        (Some(VarInt(0)) | None, Some(y)) => Some(Duration::from_millis(y.0)),
-7759        (Some(x), Some(VarInt(0)) | None) => Some(Duration::from_millis(x.0)),
-7760        (Some(x), Some(y)) => Some(Duration::from_millis(cmp::min(x, y).0)),
-7761    }
-7762}
-7763
-7764#[cfg(test)]
-7765mod tests {
-7766    use super::*;
-7767
-7768    #[test]
-7769    fn negotiate_max_idle_timeout_commutative() {
-7770        let test_params = [
-7771            (None, None, None),
-7772            (None, Some(VarInt(0)), None),
-7773            (None, Some(VarInt(2)), Some(Duration::from_millis(2))),
-7774            (Some(VarInt(0)), Some(VarInt(0)), None),
-7775            (
-7776                Some(VarInt(2)),
-7777                Some(VarInt(0)),
-7778                Some(Duration::from_millis(2)),
-7779            ),
-7780            (
-7781                Some(VarInt(1)),
-7782                Some(VarInt(4)),
-7783                Some(Duration::from_millis(1)),
-7784            ),
-7785        ];
-7786
-7787        for (left, right, result) in test_params {
-7788            assert_eq!(negotiate_max_idle_timeout(left, right), result);
-7789            assert_eq!(negotiate_max_idle_timeout(right, left), result);
-7790        }
-7791    }
-7792}

\ No newline at end of file
+7626/// According to the negotiation procedure, either the minimum of the timeouts or one specified is used as the negotiated value; see <https://www.rfc-editor.org/rfc/rfc9000#section-10.1-2.>
+7627///
+7628/// Returns the negotiated idle timeout as a `Duration`, or `None` when both endpoints have opted out of idle timeout.
+7629fn negotiate_max_idle_timeout(x: Option<VarInt>, y: Option<VarInt>) -> Option<Duration> {
+7630    match (x, y) {
+7631        (Some(VarInt(0)) | None, Some(VarInt(0)) | None) => None,
+7632        (Some(VarInt(0)) | None, Some(y)) => Some(Duration::from_millis(y.0)),
+7633        (Some(x), Some(VarInt(0)) | None) => Some(Duration::from_millis(x.0)),
+7634        (Some(x), Some(y)) => Some(Duration::from_millis(cmp::min(x, y).0)),
+7635    }
+7636}
+7637
+7638#[cfg(test)]
+7639mod tests {
+7640    use super::*;
+7641
+7642    #[test]
+7643    fn negotiate_max_idle_timeout_commutative() {
+7644        let test_params = [
+7645            (None, None, None),
+7646            (None, Some(VarInt(0)), None),
+7647            (None, Some(VarInt(2)), Some(Duration::from_millis(2))),
+7648            (Some(VarInt(0)), Some(VarInt(0)), None),
+7649            (
+7650                Some(VarInt(2)),
+7651                Some(VarInt(0)),
+7652                Some(Duration::from_millis(2)),
+7653            ),
+7654            (
+7655                Some(VarInt(1)),
+7656                Some(VarInt(4)),
+7657                Some(Duration::from_millis(1)),
+7658            ),
+7659        ];
+7660
+7661        for (left, right, result) in test_params {
+7662            assert_eq!(negotiate_max_idle_timeout(left, right), result);
+7663            assert_eq!(negotiate_max_idle_timeout(right, left), result);
+7664        }
+7665    }
+7666}

\ No newline at end of file
diff --git a/pr/616/docs/src/noq_proto/connection/paths.rs.html b/pr/616/docs/src/noq_proto/connection/paths.rs.html
index 2886ad45e..666df7311 100644
--- a/pr/616/docs/src/noq_proto/connection/paths.rs.html
+++ b/pr/616/docs/src/noq_proto/connection/paths.rs.html
@@ -535,622 +535,613 @@
 535
 536                let prev_status = std::mem::replace(&mut self.open_status, OpenStatus::Informed);
 537                OnPathResponseReceived::OnPath {
-538                    was_open: matches!(
-539                        prev_status,
-540                        OpenStatus::Informed | OpenStatus::Revalidating
-541                    ),
-542                }
-543            }
-544            // Response to an on-path PathChallenge that does not validate this path.
-545            Some(info) => {
-546                // This is a valid path response, but this validates a 4-tuple we no longer
-547                // have in use. Keep only sent challenges for the current path.
-548                self.on_path_challenges_unconfirmed
-549                    .retain(|_token, i| i.network_path == self.network_path);
-550
-551                // If there are no challenges for the current path, schedule one
-552                if !self.on_path_challenges_unconfirmed.is_empty() {
-553                    self.pending_on_path_challenge = true;
-554                }
-555                OnPathResponseReceived::Ignored {
-556                    sent_on: info.network_path,
-557                    current_path: self.network_path,
-558                }
-559            }
-560            None => {
-561                // Response to an unknown PathChallenge. Does not indicate failure.
-562                OnPathResponseReceived::Unknown
-563            }
-564        }
-565    }
-566
-567    /// Removes all on-path challenges we remember and cancels sending new on-path challenges.
-568    pub(super) fn reset_on_path_challenges(&mut self) {
-569        self.on_path_challenges_unconfirmed.clear();
-570        self.pending_on_path_challenge = false;
-571    }
-572
-573    #[cfg(feature = "qlog")]
-574    pub(super) fn qlog_recovery_metrics(
-575        &mut self,
-576        path_id: PathId,
-577    ) -> Option<RecoveryMetricsUpdated> {
-578        let controller_metrics = self.congestion.metrics();
-579
-580        let metrics = RecoveryMetrics {
-581            min_rtt: Some(self.rtt.min),
-582            smoothed_rtt: Some(self.rtt.get()),
-583            latest_rtt: Some(self.rtt.latest),
-584            rtt_variance: Some(self.rtt.var),
-585            pto_count: Some(self.pto_count),
-586            bytes_in_flight: Some(self.in_flight.bytes),
-587            packets_in_flight: Some(self.in_flight.ack_eliciting),
-588
-589            congestion_window: Some(controller_metrics.congestion_window),
-590            ssthresh: controller_metrics.ssthresh,
-591            pacing_rate: controller_metrics.pacing_rate,
-592        };
-593
-594        let event = metrics.to_qlog_event(path_id, &self.recovery_metrics);
-595        self.recovery_metrics = metrics;
-596        event
-597    }
-598
-599    /// Return how long we need to wait before sending `bytes_to_send`
-600    ///
-601    /// See [`Pacer::delay`].
-602    pub(super) fn pacing_delay(&mut self, bytes_to_send: u64, now: Instant) -> Option<Duration> {
-603        let smoothed_rtt = self.rtt.get();
-604        let metrics = self.congestion.metrics();
-605        self.pacing.delay(
-606            smoothed_rtt,
-607            bytes_to_send,
-608            self.current_mtu(),
-609            metrics.congestion_window,
-610            now,
-611            metrics.send_quantum,
-612            metrics.pacing_rate,
-613        )
-614    }
-615
-616    /// Updates the last observed address report received on this path.
-617    ///
-618    /// If the address was updated, it's returned to be informed to the application.
-619    #[must_use = "updated observed address must be reported to the application"]
-620    pub(super) fn update_observed_addr_report(
-621        &mut self,
-622        observed: ObservedAddr,
-623    ) -> Option<SocketAddr> {
-624        match self.last_observed_addr_report.as_mut() {
-625            Some(prev) => {
-626                if prev.seq_no >= observed.seq_no {
-627                    // frames that do not increase the sequence number on this path are ignored
-628                    None
-629                } else if prev.ip == observed.ip && prev.port == observed.port {
-630                    // keep track of the last seq_no but do not report the address as updated
-631                    prev.seq_no = observed.seq_no;
-632                    None
-633                } else {
-634                    let addr = observed.socket_addr();
-635                    self.last_observed_addr_report = Some(observed);
-636                    Some(addr)
-637                }
-638            }
-639            None => {
-640                let addr = observed.socket_addr();
-641                self.last_observed_addr_report = Some(observed);
-642                Some(addr)
-643            }
-644        }
-645    }
-646
-647    pub(crate) fn remote_status(&self) -> Option<PathStatus> {
-648        self.status.remote_status.map(|(_seq, status)| status)
-649    }
-650
-651    pub(crate) fn local_status(&self) -> PathStatus {
-652        self.status.local_status
-653    }
-654
-655    /// Tag uniquely identifying a path in a connection.
-656    ///
-657    /// When a migration happens on the same [`PathId`] we still detect a change in the
-658    /// 4-tuple and generate a new [`PathData`] for it. Each such generation has a unique
-659    /// value to keep track of which 4-tuple a packet belonged to.
-660    pub(super) fn generation(&self) -> u64 {
-661        self.generation
-662    }
-663}
-664
-665pub(super) enum OnPathResponseReceived {
-666    /// This response validates the path on its current remote address.
-667    OnPath { was_open: bool },
-668    /// The received token is unknown.
-669    Unknown,
-670    /// The response is valid but it's not usable for path validation.
-671    Ignored {
-672        sent_on: FourTuple,
-673        current_path: FourTuple,
-674    },
-675}
-676
-677#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
-678pub(super) enum OpenStatus {
-679    /// A first packet has not been sent using this [`PathId`].
-680    #[default]
-681    Pending,
-682    /// The first packet has been sent using this [`PathId`]. However, it is not yet deemed good
-683    /// enough to be reported to the application.
-684    Sent,
-685    /// The application has been informed of this path.
-686    Informed,
-687    /// The path was [`Self::Informed`] before, but we want to trigger path validation again.
-688    ///
-689    /// This is used to ensure we properly stop trying to re-send path challenges eventually, without
-690    /// having to switch to [`Self::Pending`] when re-validating, as that would trigger another
-691    /// application-level event about the path opening once validation succeeds.
-692    Revalidating,
-693}
-694
-695/// Congestion metrics as described in [`recovery_metrics_updated`].
-696///
-697/// [`recovery_metrics_updated`]: https://datatracker.ietf.org/doc/html/draft-ietf-quic-qlog-quic-events.html#name-recovery_metrics_updated
-698#[cfg(feature = "qlog")]
-699#[derive(Default, Clone, PartialEq, Debug)]
-700#[non_exhaustive]
-701struct RecoveryMetrics {
-702    pub min_rtt: Option<Duration>,
-703    pub smoothed_rtt: Option<Duration>,
-704    pub latest_rtt: Option<Duration>,
-705    pub rtt_variance: Option<Duration>,
-706    pub pto_count: Option<u32>,
-707    pub bytes_in_flight: Option<u64>,
-708    pub packets_in_flight: Option<u64>,
-709    pub congestion_window: Option<u64>,
-710    pub ssthresh: Option<u64>,
-711    pub pacing_rate: Option<u64>,
-712}
-713
-714#[cfg(feature = "qlog")]
-715impl RecoveryMetrics {
-716    /// Retain only values that have been updated since the last snapshot.
-717    fn retain_updated(&self, previous: &Self) -> Self {
-718        macro_rules! keep_if_changed {
-719            ($name:ident) => {
-720                if previous.$name == self.$name {
-721                    None
-722                } else {
-723                    self.$name
-724                }
-725            };
-726        }
-727
-728        Self {
-729            min_rtt: keep_if_changed!(min_rtt),
-730            smoothed_rtt: keep_if_changed!(smoothed_rtt),
-731            latest_rtt: keep_if_changed!(latest_rtt),
-732            rtt_variance: keep_if_changed!(rtt_variance),
-733            pto_count: keep_if_changed!(pto_count),
-734            bytes_in_flight: keep_if_changed!(bytes_in_flight),
-735            packets_in_flight: keep_if_changed!(packets_in_flight),
-736            congestion_window: keep_if_changed!(congestion_window),
-737            ssthresh: keep_if_changed!(ssthresh),
-738            pacing_rate: keep_if_changed!(pacing_rate),
+538                    was_open: matches!(prev_status, OpenStatus::Informed),
+539                }
+540            }
+541            // Response to an on-path PathChallenge that does not validate this path.
+542            Some(info) => {
+543                // This is a valid path response, but this validates a 4-tuple we no longer
+544                // have in use. Keep only sent challenges for the current path.
+545                self.on_path_challenges_unconfirmed
+546                    .retain(|_token, i| i.network_path == self.network_path);
+547
+548                // If there are no challenges for the current path, schedule one
+549                if !self.on_path_challenges_unconfirmed.is_empty() {
+550                    self.pending_on_path_challenge = true;
+551                }
+552                OnPathResponseReceived::Ignored {
+553                    sent_on: info.network_path,
+554                    current_path: self.network_path,
+555                }
+556            }
+557            None => {
+558                // Response to an unknown PathChallenge. Does not indicate failure.
+559                OnPathResponseReceived::Unknown
+560            }
+561        }
+562    }
+563
+564    /// Removes all on-path challenges we remember and cancels sending new on-path challenges.
+565    pub(super) fn reset_on_path_challenges(&mut self) {
+566        self.on_path_challenges_unconfirmed.clear();
+567        self.pending_on_path_challenge = false;
+568    }
+569
+570    #[cfg(feature = "qlog")]
+571    pub(super) fn qlog_recovery_metrics(
+572        &mut self,
+573        path_id: PathId,
+574    ) -> Option<RecoveryMetricsUpdated> {
+575        let controller_metrics = self.congestion.metrics();
+576
+577        let metrics = RecoveryMetrics {
+578            min_rtt: Some(self.rtt.min),
+579            smoothed_rtt: Some(self.rtt.get()),
+580            latest_rtt: Some(self.rtt.latest),
+581            rtt_variance: Some(self.rtt.var),
+582            pto_count: Some(self.pto_count),
+583            bytes_in_flight: Some(self.in_flight.bytes),
+584            packets_in_flight: Some(self.in_flight.ack_eliciting),
+585
+586            congestion_window: Some(controller_metrics.congestion_window),
+587            ssthresh: controller_metrics.ssthresh,
+588            pacing_rate: controller_metrics.pacing_rate,
+589        };
+590
+591        let event = metrics.to_qlog_event(path_id, &self.recovery_metrics);
+592        self.recovery_metrics = metrics;
+593        event
+594    }
+595
+596    /// Return how long we need to wait before sending `bytes_to_send`
+597    ///
+598    /// See [`Pacer::delay`].
+599    pub(super) fn pacing_delay(&mut self, bytes_to_send: u64, now: Instant) -> Option<Duration> {
+600        let smoothed_rtt = self.rtt.get();
+601        let metrics = self.congestion.metrics();
+602        self.pacing.delay(
+603            smoothed_rtt,
+604            bytes_to_send,
+605            self.current_mtu(),
+606            metrics.congestion_window,
+607            now,
+608            metrics.send_quantum,
+609            metrics.pacing_rate,
+610        )
+611    }
+612
+613    /// Updates the last observed address report received on this path.
+614    ///
+615    /// If the address was updated, it's returned to be informed to the application.
+616    #[must_use = "updated observed address must be reported to the application"]
+617    pub(super) fn update_observed_addr_report(
+618        &mut self,
+619        observed: ObservedAddr,
+620    ) -> Option<SocketAddr> {
+621        match self.last_observed_addr_report.as_mut() {
+622            Some(prev) => {
+623                if prev.seq_no >= observed.seq_no {
+624                    // frames that do not increase the sequence number on this path are ignored
+625                    None
+626                } else if prev.ip == observed.ip && prev.port == observed.port {
+627                    // keep track of the last seq_no but do not report the address as updated
+628                    prev.seq_no = observed.seq_no;
+629                    None
+630                } else {
+631                    let addr = observed.socket_addr();
+632                    self.last_observed_addr_report = Some(observed);
+633                    Some(addr)
+634                }
+635            }
+636            None => {
+637                let addr = observed.socket_addr();
+638                self.last_observed_addr_report = Some(observed);
+639                Some(addr)
+640            }
+641        }
+642    }
+643
+644    pub(crate) fn remote_status(&self) -> Option<PathStatus> {
+645        self.status.remote_status.map(|(_seq, status)| status)
+646    }
+647
+648    pub(crate) fn local_status(&self) -> PathStatus {
+649        self.status.local_status
+650    }
+651
+652    /// Tag uniquely identifying a path in a connection.
+653    ///
+654    /// When a migration happens on the same [`PathId`] we still detect a change in the
+655    /// 4-tuple and generate a new [`PathData`] for it. Each such generation has a unique
+656    /// value to keep track of which 4-tuple a packet belonged to.
+657    pub(super) fn generation(&self) -> u64 {
+658        self.generation
+659    }
+660}
+661
+662pub(super) enum OnPathResponseReceived {
+663    /// This response validates the path on its current remote address.
+664    OnPath { was_open: bool },
+665    /// The received token is unknown.
+666    Unknown,
+667    /// The response is valid but it's not usable for path validation.
+668    Ignored {
+669        sent_on: FourTuple,
+670        current_path: FourTuple,
+671    },
+672}
+673
+674#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
+675pub(super) enum OpenStatus {
+676    /// A first packet has not been sent using this [`PathId`].
+677    #[default]
+678    Pending,
+679    /// The first packet has been sent using this [`PathId`]. However, it is not yet deemed good
+680    /// enough to be reported to the application.
+681    Sent,
+682    /// The application has been informed of this path.
+683    Informed,
+684}
+685
+686/// Congestion metrics as described in [`recovery_metrics_updated`].
+687///
+688/// [`recovery_metrics_updated`]: https://datatracker.ietf.org/doc/html/draft-ietf-quic-qlog-quic-events.html#name-recovery_metrics_updated
+689#[cfg(feature = "qlog")]
+690#[derive(Default, Clone, PartialEq, Debug)]
+691#[non_exhaustive]
+692struct RecoveryMetrics {
+693    pub min_rtt: Option<Duration>,
+694    pub smoothed_rtt: Option<Duration>,
+695    pub latest_rtt: Option<Duration>,
+696    pub rtt_variance: Option<Duration>,
+697    pub pto_count: Option<u32>,
+698    pub bytes_in_flight: Option<u64>,
+699    pub packets_in_flight: Option<u64>,
+700    pub congestion_window: Option<u64>,
+701    pub ssthresh: Option<u64>,
+702    pub pacing_rate: Option<u64>,
+703}
+704
+705#[cfg(feature = "qlog")]
+706impl RecoveryMetrics {
+707    /// Retain only values that have been updated since the last snapshot.
+708    fn retain_updated(&self, previous: &Self) -> Self {
+709        macro_rules! keep_if_changed {
+710            ($name:ident) => {
+711                if previous.$name == self.$name {
+712                    None
+713                } else {
+714                    self.$name
+715                }
+716            };
+717        }
+718
+719        Self {
+720            min_rtt: keep_if_changed!(min_rtt),
+721            smoothed_rtt: keep_if_changed!(smoothed_rtt),
+722            latest_rtt: keep_if_changed!(latest_rtt),
+723            rtt_variance: keep_if_changed!(rtt_variance),
+724            pto_count: keep_if_changed!(pto_count),
+725            bytes_in_flight: keep_if_changed!(bytes_in_flight),
+726            packets_in_flight: keep_if_changed!(packets_in_flight),
+727            congestion_window: keep_if_changed!(congestion_window),
+728            ssthresh: keep_if_changed!(ssthresh),
+729            pacing_rate: keep_if_changed!(pacing_rate),
+730        }
+731    }
+732
+733    /// Emit a `MetricsUpdated` event containing only updated values
+734    fn to_qlog_event(&self, path_id: PathId, previous: &Self) -> Option<RecoveryMetricsUpdated> {
+735        let updated = self.retain_updated(previous);
+736
+737        if updated == Self::default() {
+738            return None;
 739        }
-740    }
-741
-742    /// Emit a `MetricsUpdated` event containing only updated values
-743    fn to_qlog_event(&self, path_id: PathId, previous: &Self) -> Option<RecoveryMetricsUpdated> {
-744        let updated = self.retain_updated(previous);
-745
-746        if updated == Self::default() {
-747            return None;
-748        }
-749
-750        Some(RecoveryMetricsUpdated {
-751            min_rtt: updated.min_rtt.map(|rtt| rtt.as_secs_f32()),
-752            smoothed_rtt: updated.smoothed_rtt.map(|rtt| rtt.as_secs_f32()),
-753            latest_rtt: updated.latest_rtt.map(|rtt| rtt.as_secs_f32()),
-754            rtt_variance: updated.rtt_variance.map(|rtt| rtt.as_secs_f32()),
-755            pto_count: updated
-756                .pto_count
-757                .map(|count| count.try_into().unwrap_or(u16::MAX)),
-758            bytes_in_flight: updated.bytes_in_flight,
-759            packets_in_flight: updated.packets_in_flight,
-760            congestion_window: updated.congestion_window,
-761            ssthresh: updated.ssthresh,
-762            pacing_rate: updated.pacing_rate,
-763            path_id: Some(path_id.as_u32() as u64),
-764        })
-765    }
-766}
-767
-768/// RTT estimation for a particular network path
-769#[derive(Copy, Clone, Debug)]
-770pub struct RttEstimator {
-771    /// The most recent RTT measurement made when receiving an ack for a previously unacked packet
-772    latest: Duration,
-773    /// The smoothed RTT of the connection, computed as described in RFC6298
-774    smoothed: Option<Duration>,
-775    /// The RTT variance, computed as described in RFC6298
-776    var: Duration,
-777    /// The minimum RTT seen in the connection, ignoring ack delay.
-778    min: Duration,
-779}
-780
-781impl RttEstimator {
-782    pub(super) fn new(initial_rtt: Duration) -> Self {
-783        Self {
-784            latest: initial_rtt,
-785            smoothed: None,
-786            var: initial_rtt / 2,
-787            min: initial_rtt,
-788        }
-789    }
-790
-791    /// Resets the estimator using a new initial_rtt value.
-792    ///
-793    /// This only resets the initial_rtt **if** no samples have been recorded yet. If there
-794    /// are any recorded samples the initial estimate can not be adjusted after the fact.
-795    ///
-796    /// This is useful when you receive a PATH_RESPONSE in the first packet received on a
-797    /// new path. In this case you can use the delay of the PATH_CHALLENGE-PATH_RESPONSE as
-798    /// the initial RTT to get a better expected estimation.
-799    ///
-800    /// A PATH_CHALLENGE-PATH_RESPONSE pair later in the connection should not be used
-801    /// explicitly as an estimation since PATH_CHALLENGE is an ACK-eliciting packet itself
-802    /// already.
-803    pub(crate) fn reset_initial_rtt(&mut self, initial_rtt: Duration) {
-804        if self.smoothed.is_none() {
-805            self.latest = initial_rtt;
-806            self.var = initial_rtt / 2;
-807            self.min = initial_rtt;
-808        }
-809    }
-810
-811    /// The current best RTT estimation.
-812    pub fn get(&self) -> Duration {
-813        self.smoothed.unwrap_or(self.latest)
-814    }
-815
-816    /// Conservative estimate of RTT
-817    ///
-818    /// Takes the maximum of smoothed and latest RTT, as recommended
-819    /// in 6.1.2 of the recovery spec (draft 29).
-820    pub fn conservative(&self) -> Duration {
-821        self.get().max(self.latest)
-822    }
-823
-824    /// Minimum RTT registered so far for this estimator.
-825    pub fn min(&self) -> Duration {
-826        self.min
-827    }
-828
-829    /// PTO computed as described in RFC9002#6.2.1.
-830    pub(crate) fn pto_base(&self) -> Duration {
-831        self.get() + cmp::max(4 * self.var, TIMER_GRANULARITY)
-832    }
-833
-834    /// Records an RTT sample.
-835    pub(crate) fn update(&mut self, ack_delay: Duration, rtt: Duration) {
-836        self.latest = rtt;
-837        // https://www.rfc-editor.org/rfc/rfc9002.html#section-5.2-3:
-838        // min_rtt does not adjust for ack_delay to avoid underestimating.
-839        self.min = cmp::min(self.min, self.latest);
-840        // Based on RFC6298.
-841        if let Some(smoothed) = self.smoothed {
-842            let adjusted_rtt = if self.min + ack_delay <= self.latest {
-843                self.latest - ack_delay
-844            } else {
-845                self.latest
-846            };
-847            let var_sample = smoothed.abs_diff(adjusted_rtt);
-848            self.var = (3 * self.var + var_sample) / 4;
-849            self.smoothed = Some((7 * smoothed + adjusted_rtt) / 8);
-850        } else {
-851            self.smoothed = Some(self.latest);
-852            self.var = self.latest / 2;
-853            self.min = self.latest;
-854        }
-855    }
-856}
-857
-858#[derive(Default, Debug)]
-859pub(crate) struct PathResponses {
-860    pending: Vec<PathResponse>,
-861}
-862
-863impl PathResponses {
-864    pub(crate) fn push(&mut self, packet: u64, token: u64, network_path: FourTuple) {
-865        /// Arbitrary permissive limit to prevent abuse
-866        const MAX_PATH_RESPONSES: usize = 16;
-867        let response = PathResponse {
-868            packet,
-869            token,
-870            network_path,
-871        };
-872        let existing = self
-873            .pending
-874            .iter_mut()
-875            .find(|x| x.network_path.remote == network_path.remote);
-876        if let Some(existing) = existing {
-877            // Update a queued response
-878            if existing.packet <= packet {
-879                *existing = response;
-880            }
-881            return;
-882        }
-883        if self.pending.len() < MAX_PATH_RESPONSES {
-884            self.pending.push(response);
-885        } else {
-886            // We don't expect to ever hit this with well-behaved peers, so we don't bother dropping
-887            // older challenges.
-888            trace!("ignoring excessive PATH_CHALLENGE");
-889        }
-890    }
-891
-892    pub(crate) fn pop_off_path(&mut self, network_path: FourTuple) -> Option<(u64, FourTuple)> {
-893        let response = *self.pending.last()?;
-894        // We use an exact comparison here, because once we've received for the first time,
-895        // we really should either already have a local_ip, or we will never get one
-896        // (because our OS doesn't support it).
-897        if response.network_path == network_path {
-898            // We don't bother searching further because we expect that the on-path response will
-899            // get drained in the immediate future by a call to `pop_on_path`
-900            return None;
-901        }
-902        self.pending.pop();
-903        Some((response.token, response.network_path))
-904    }
-905
-906    pub(crate) fn pop_on_path(&mut self, network_path: FourTuple) -> Option<u64> {
-907        let response = *self.pending.last()?;
-908        // Using an exact comparison. See explanation in `pop_off_path`.
-909        if response.network_path != network_path {
-910            // We don't bother searching further because we expect that the off-path response will
-911            // get drained in the immediate future by a call to `pop_off_path`
-912            return None;
-913        }
-914        self.pending.pop();
-915        Some(response.token)
-916    }
-917
-918    pub(crate) fn is_empty(&self) -> bool {
-919        self.pending.is_empty()
-920    }
-921}
-922
-923#[derive(Copy, Clone, Debug)]
-924struct PathResponse {
-925    /// The packet number the corresponding PATH_CHALLENGE was received in
-926    packet: u64,
-927    /// The token of the PATH_CHALLENGE
-928    token: u64,
-929    /// The path the corresponding PATH_CHALLENGE was received from
-930    network_path: FourTuple,
-931}
-932
-933/// Summary statistics of packets that have been sent on a particular path, but which have not yet
-934/// been acked or deemed lost
-935#[derive(Debug)]
-936pub(super) struct InFlight {
-937    /// Sum of the sizes of all sent packets considered "in flight" by congestion control
-938    ///
-939    /// The size does not include IP or UDP overhead. Packets only containing ACK frames do not
-940    /// count towards this to ensure congestion control does not impede congestion feedback.
-941    pub(super) bytes: u64,
-942    /// Number of packets in flight containing frames other than ACK and PADDING
-943    ///
-944    /// This can be 0 even when bytes is not 0 because PADDING frames cause a packet to be
-945    /// considered "in flight" by congestion control. However, if this is nonzero, bytes will always
-946    /// also be nonzero.
-947    pub(super) ack_eliciting: u64,
-948}
-949
-950impl InFlight {
-951    fn new() -> Self {
-952        Self {
-953            bytes: 0,
-954            ack_eliciting: 0,
-955        }
-956    }
-957
-958    fn insert(&mut self, packet: &SentPacket) {
-959        self.bytes += u64::from(packet.size);
-960        self.ack_eliciting += u64::from(packet.ack_eliciting);
-961    }
-962
-963    /// Update counters to account for a packet becoming acknowledged, lost, or abandoned
-964    fn remove(&mut self, packet: &SentPacket) {
-965        self.bytes -= u64::from(packet.size);
-966        self.ack_eliciting -= u64::from(packet.ack_eliciting);
-967    }
-968}
-969
-970/// State for QUIC-MULTIPATH PATH_STATUS_AVAILABLE and PATH_STATUS_BACKUP frames
-971#[derive(Debug, Clone, Default)]
-972pub(super) struct PathStatusState {
-973    /// The local status
-974    local_status: PathStatus,
-975    /// Local sequence number, for both PATH_STATUS_AVAILABLE and PATH_STATUS_BACKUP
-976    ///
-977    /// This is the number of the *next* path status frame to be sent.
-978    local_seq: VarInt,
-979    /// The status set by the remote
-980    remote_status: Option<(VarInt, PathStatus)>,
-981}
-982
-983impl PathStatusState {
-984    /// To be called on received PATH_STATUS_AVAILABLE/PATH_STATUS_BACKUP frames
-985    pub(super) fn remote_update(&mut self, status: PathStatus, seq: VarInt) {
-986        if self.remote_status.is_some_and(|(curr, _)| curr >= seq) {
-987            return trace!(%seq, "ignoring path status update");
-988        }
-989
-990        let prev = self.remote_status.replace((seq, status)).map(|(_, s)| s);
-991        if prev != Some(status) {
-992            debug!(?status, ?seq, "remote changed path status");
+740
+741        Some(RecoveryMetricsUpdated {
+742            min_rtt: updated.min_rtt.map(|rtt| rtt.as_secs_f32()),
+743            smoothed_rtt: updated.smoothed_rtt.map(|rtt| rtt.as_secs_f32()),
+744            latest_rtt: updated.latest_rtt.map(|rtt| rtt.as_secs_f32()),
+745            rtt_variance: updated.rtt_variance.map(|rtt| rtt.as_secs_f32()),
+746            pto_count: updated
+747                .pto_count
+748                .map(|count| count.try_into().unwrap_or(u16::MAX)),
+749            bytes_in_flight: updated.bytes_in_flight,
+750            packets_in_flight: updated.packets_in_flight,
+751            congestion_window: updated.congestion_window,
+752            ssthresh: updated.ssthresh,
+753            pacing_rate: updated.pacing_rate,
+754            path_id: Some(path_id.as_u32() as u64),
+755        })
+756    }
+757}
+758
+759/// RTT estimation for a particular network path
+760#[derive(Copy, Clone, Debug)]
+761pub struct RttEstimator {
+762    /// The most recent RTT measurement made when receiving an ack for a previously unacked packet
+763    latest: Duration,
+764    /// The smoothed RTT of the connection, computed as described in RFC6298
+765    smoothed: Option<Duration>,
+766    /// The RTT variance, computed as described in RFC6298
+767    var: Duration,
+768    /// The minimum RTT seen in the connection, ignoring ack delay.
+769    min: Duration,
+770}
+771
+772impl RttEstimator {
+773    pub(super) fn new(initial_rtt: Duration) -> Self {
+774        Self {
+775            latest: initial_rtt,
+776            smoothed: None,
+777            var: initial_rtt / 2,
+778            min: initial_rtt,
+779        }
+780    }
+781
+782    /// Resets the estimator using a new initial_rtt value.
+783    ///
+784    /// This only resets the initial_rtt **if** no samples have been recorded yet. If there
+785    /// are any recorded samples the initial estimate can not be adjusted after the fact.
+786    ///
+787    /// This is useful when you receive a PATH_RESPONSE in the first packet received on a
+788    /// new path. In this case you can use the delay of the PATH_CHALLENGE-PATH_RESPONSE as
+789    /// the initial RTT to get a better expected estimation.
+790    ///
+791    /// A PATH_CHALLENGE-PATH_RESPONSE pair later in the connection should not be used
+792    /// explicitly as an estimation since PATH_CHALLENGE is an ACK-eliciting packet itself
+793    /// already.
+794    pub(crate) fn reset_initial_rtt(&mut self, initial_rtt: Duration) {
+795        if self.smoothed.is_none() {
+796            self.latest = initial_rtt;
+797            self.var = initial_rtt / 2;
+798            self.min = initial_rtt;
+799        }
+800    }
+801
+802    /// The current best RTT estimation.
+803    pub fn get(&self) -> Duration {
+804        self.smoothed.unwrap_or(self.latest)
+805    }
+806
+807    /// Conservative estimate of RTT
+808    ///
+809    /// Takes the maximum of smoothed and latest RTT, as recommended
+810    /// in 6.1.2 of the recovery spec (draft 29).
+811    pub fn conservative(&self) -> Duration {
+812        self.get().max(self.latest)
+813    }
+814
+815    /// Minimum RTT registered so far for this estimator.
+816    pub fn min(&self) -> Duration {
+817        self.min
+818    }
+819
+820    /// PTO computed as described in RFC9002#6.2.1.
+821    pub(crate) fn pto_base(&self) -> Duration {
+822        self.get() + cmp::max(4 * self.var, TIMER_GRANULARITY)
+823    }
+824
+825    /// Records an RTT sample.
+826    pub(crate) fn update(&mut self, ack_delay: Duration, rtt: Duration) {
+827        self.latest = rtt;
+828        // https://www.rfc-editor.org/rfc/rfc9002.html#section-5.2-3:
+829        // min_rtt does not adjust for ack_delay to avoid underestimating.
+830        self.min = cmp::min(self.min, self.latest);
+831        // Based on RFC6298.
+832        if let Some(smoothed) = self.smoothed {
+833            let adjusted_rtt = if self.min + ack_delay <= self.latest {
+834                self.latest - ack_delay
+835            } else {
+836                self.latest
+837            };
+838            let var_sample = smoothed.abs_diff(adjusted_rtt);
+839            self.var = (3 * self.var + var_sample) / 4;
+840            self.smoothed = Some((7 * smoothed + adjusted_rtt) / 8);
+841        } else {
+842            self.smoothed = Some(self.latest);
+843            self.var = self.latest / 2;
+844            self.min = self.latest;
+845        }
+846    }
+847}
+848
+849#[derive(Default, Debug)]
+850pub(crate) struct PathResponses {
+851    pending: Vec<PathResponse>,
+852}
+853
+854impl PathResponses {
+855    pub(crate) fn push(&mut self, packet: u64, token: u64, network_path: FourTuple) {
+856        /// Arbitrary permissive limit to prevent abuse
+857        const MAX_PATH_RESPONSES: usize = 16;
+858        let response = PathResponse {
+859            packet,
+860            token,
+861            network_path,
+862        };
+863        let existing = self
+864            .pending
+865            .iter_mut()
+866            .find(|x| x.network_path.remote == network_path.remote);
+867        if let Some(existing) = existing {
+868            // Update a queued response
+869            if existing.packet <= packet {
+870                *existing = response;
+871            }
+872            return;
+873        }
+874        if self.pending.len() < MAX_PATH_RESPONSES {
+875            self.pending.push(response);
+876        } else {
+877            // We don't expect to ever hit this with well-behaved peers, so we don't bother dropping
+878            // older challenges.
+879            trace!("ignoring excessive PATH_CHALLENGE");
+880        }
+881    }
+882
+883    pub(crate) fn pop_off_path(&mut self, network_path: FourTuple) -> Option<(u64, FourTuple)> {
+884        let response = *self.pending.last()?;
+885        // We use an exact comparison here, because once we've received for the first time,
+886        // we really should either already have a local_ip, or we will never get one
+887        // (because our OS doesn't support it).
+888        if response.network_path == network_path {
+889            // We don't bother searching further because we expect that the on-path response will
+890            // get drained in the immediate future by a call to `pop_on_path`
+891            return None;
+892        }
+893        self.pending.pop();
+894        Some((response.token, response.network_path))
+895    }
+896
+897    pub(crate) fn pop_on_path(&mut self, network_path: FourTuple) -> Option<u64> {
+898        let response = *self.pending.last()?;
+899        // Using an exact comparison. See explanation in `pop_off_path`.
+900        if response.network_path != network_path {
+901            // We don't bother searching further because we expect that the off-path response will
+902            // get drained in the immediate future by a call to `pop_off_path`
+903            return None;
+904        }
+905        self.pending.pop();
+906        Some(response.token)
+907    }
+908
+909    pub(crate) fn is_empty(&self) -> bool {
+910        self.pending.is_empty()
+911    }
+912}
+913
+914#[derive(Copy, Clone, Debug)]
+915struct PathResponse {
+916    /// The packet number the corresponding PATH_CHALLENGE was received in
+917    packet: u64,
+918    /// The token of the PATH_CHALLENGE
+919    token: u64,
+920    /// The path the corresponding PATH_CHALLENGE was received from
+921    network_path: FourTuple,
+922}
+923
+924/// Summary statistics of packets that have been sent on a particular path, but which have not yet
+925/// been acked or deemed lost
+926#[derive(Debug)]
+927pub(super) struct InFlight {
+928    /// Sum of the sizes of all sent packets considered "in flight" by congestion control
+929    ///
+930    /// The size does not include IP or UDP overhead. Packets only containing ACK frames do not
+931    /// count towards this to ensure congestion control does not impede congestion feedback.
+932    pub(super) bytes: u64,
+933    /// Number of packets in flight containing frames other than ACK and PADDING
+934    ///
+935    /// This can be 0 even when bytes is not 0 because PADDING frames cause a packet to be
+936    /// considered "in flight" by congestion control. However, if this is nonzero, bytes will always
+937    /// also be nonzero.
+938    pub(super) ack_eliciting: u64,
+939}
+940
+941impl InFlight {
+942    fn new() -> Self {
+943        Self {
+944            bytes: 0,
+945            ack_eliciting: 0,
+946        }
+947    }
+948
+949    fn insert(&mut self, packet: &SentPacket) {
+950        self.bytes += u64::from(packet.size);
+951        self.ack_eliciting += u64::from(packet.ack_eliciting);
+952    }
+953
+954    /// Update counters to account for a packet becoming acknowledged, lost, or abandoned
+955    fn remove(&mut self, packet: &SentPacket) {
+956        self.bytes -= u64::from(packet.size);
+957        self.ack_eliciting -= u64::from(packet.ack_eliciting);
+958    }
+959}
+960
+961/// State for QUIC-MULTIPATH PATH_STATUS_AVAILABLE and PATH_STATUS_BACKUP frames
+962#[derive(Debug, Clone, Default)]
+963pub(super) struct PathStatusState {
+964    /// The local status
+965    local_status: PathStatus,
+966    /// Local sequence number, for both PATH_STATUS_AVAILABLE and PATH_STATUS_BACKUP
+967    ///
+968    /// This is the number of the *next* path status frame to be sent.
+969    local_seq: VarInt,
+970    /// The status set by the remote
+971    remote_status: Option<(VarInt, PathStatus)>,
+972}
+973
+974impl PathStatusState {
+975    /// To be called on received PATH_STATUS_AVAILABLE/PATH_STATUS_BACKUP frames
+976    pub(super) fn remote_update(&mut self, status: PathStatus, seq: VarInt) {
+977        if self.remote_status.is_some_and(|(curr, _)| curr >= seq) {
+978            return trace!(%seq, "ignoring path status update");
+979        }
+980
+981        let prev = self.remote_status.replace((seq, status)).map(|(_, s)| s);
+982        if prev != Some(status) {
+983            debug!(?status, ?seq, "remote changed path status");
+984        }
+985    }
+986
+987    /// Updates the local status
+988    ///
+989    /// If the local status changed, the previous value is returned
+990    pub(super) fn local_update(&mut self, status: PathStatus) -> Option<PathStatus> {
+991        if self.local_status == status {
+992            return None;
 993        }
-994    }
-995
-996    /// Updates the local status
-997    ///
-998    /// If the local status changed, the previous value is returned
-999    pub(super) fn local_update(&mut self, status: PathStatus) -> Option<PathStatus> {
-1000        if self.local_status == status {
-1001            return None;
-1002        }
+994
+995        self.local_seq = self.local_seq.saturating_add(1u8);
+996        Some(std::mem::replace(&mut self.local_status, status))
+997    }
+998
+999    pub(crate) fn seq(&self) -> VarInt {
+1000        self.local_seq
+1001    }
+1002}
 1003
-1004        self.local_seq = self.local_seq.saturating_add(1u8);
-1005        Some(std::mem::replace(&mut self.local_status, status))
-1006    }
-1007
-1008    pub(crate) fn seq(&self) -> VarInt {
-1009        self.local_seq
-1010    }
-1011}
-1012
-1013/// The QUIC-MULTIPATH path status
-1014///
-1015/// See section "3.3 Path Status Management":
-1016/// <https://quicwg.org/multipath/draft-ietf-quic-multipath.html#name-path-status-management>
-1017#[cfg_attr(test, derive(test_strategy::Arbitrary))]
-1018#[derive(Debug, Copy, Clone, Default, PartialEq, Eq)]
-1019pub enum PathStatus {
-1020    /// Paths marked with as available will be used when scheduling packets
-1021    ///
-1022    /// If multiple paths are available, packets will be scheduled on whichever has
-1023    /// capacity.
-1024    #[default]
-1025    Available,
-1026    /// Paths marked as backup will only be used if there are no available paths
-1027    ///
-1028    /// If the max_idle_timeout is specified the path will be kept alive so that it does not
-1029    /// expire.
-1030    Backup,
-1031}
-1032
-1033/// Application events about paths
-1034#[derive(Debug, Clone, PartialEq, Eq)]
-1035pub enum PathEvent {
-1036    /// A new path has been opened
-1037    Opened {
-1038        /// Which path is now open
-1039        id: PathId,
+1004/// The QUIC-MULTIPATH path status
+1005///
+1006/// See section "3.3 Path Status Management":
+1007/// <https://quicwg.org/multipath/draft-ietf-quic-multipath.html#name-path-status-management>
+1008#[cfg_attr(test, derive(test_strategy::Arbitrary))]
+1009#[derive(Debug, Copy, Clone, Default, PartialEq, Eq)]
+1010pub enum PathStatus {
+1011    /// Paths marked with as available will be used when scheduling packets
+1012    ///
+1013    /// If multiple paths are available, packets will be scheduled on whichever has
+1014    /// capacity.
+1015    #[default]
+1016    Available,
+1017    /// Paths marked as backup will only be used if there are no available paths
+1018    ///
+1019    /// If the max_idle_timeout is specified the path will be kept alive so that it does not
+1020    /// expire.
+1021    Backup,
+1022}
+1023
+1024/// Application events about paths
+1025#[derive(Debug, Clone, PartialEq, Eq)]
+1026pub enum PathEvent {
+1027    /// A new path has been opened
+1028    Opened {
+1029        /// Which path is now open
+1030        id: PathId,
+1031    },
+1032    /// A path was abandoned and is no longer usable.
+1033    ///
+1034    /// This event will always be followed by [`Self::Discarded`] after some time.
+1035    Abandoned {
+1036        /// With path was abandoned.
+1037        id: PathId,
+1038        /// Reason why this path was abandoned.
+1039        reason: PathAbandonReason,
 1040    },
-1041    /// A path was abandoned and is no longer usable.
+1041    /// A path was discarded and all remaining state for it has been removed.
 1042    ///
-1043    /// This event will always be followed by [`Self::Discarded`] after some time.
-1044    Abandoned {
-1045        /// With path was abandoned.
+1043    /// This event is the last event for a path, and is always emitted after [`Self::Abandoned`].
+1044    Discarded {
+1045        /// Which path had its state dropped
 1046        id: PathId,
-1047        /// Reason why this path was abandoned.
-1048        reason: PathAbandonReason,
-1049    },
-1050    /// A path was discarded and all remaining state for it has been removed.
-1051    ///
-1052    /// This event is the last event for a path, and is always emitted after [`Self::Abandoned`].
-1053    Discarded {
-1054        /// Which path had its state dropped
-1055        id: PathId,
-1056        /// The final path stats, they are no longer available via [`Connection::stats`]
-1057        ///
-1058        /// [`Connection::stats`]: super::Connection::stats
-1059        path_stats: Box<PathStats>,
-1060    },
-1061    /// The remote changed the status of the path
-1062    ///
-1063    /// The local status is not changed because of this event. It is up to the application
-1064    /// to update the local status, which is used for packet scheduling, when the remote
-1065    /// changes the status.
-1066    RemoteStatus {
-1067        /// Path which has changed status
-1068        id: PathId,
-1069        /// The new status set by the remote
-1070        status: PathStatus,
-1071    },
-1072    /// Received an observation of our external address from the peer.
-1073    ObservedAddr {
-1074        /// Path over which the observed address was reported, [`PathId::ZERO`] when multipath is
-1075        /// not negotiated
-1076        id: PathId,
-1077        /// The address observed by the remote over this path
-1078        addr: SocketAddr,
-1079    },
-1080}
-1081
-1082/// Reason for why a path was abandoned.
-1083#[derive(Debug, Clone, Eq, PartialEq)]
-1084pub enum PathAbandonReason {
-1085    /// The path was closed locally by the application.
-1086    ApplicationClosed {
-1087        /// The error code to be sent with the abandon frame.
-1088        error_code: VarInt,
-1089    },
-1090    /// We didn't receive a path response in time after opening this path.
-1091    ValidationFailed,
-1092    /// We didn't receive any data from the remote within the path's idle timeout.
-1093    TimedOut,
-1094    /// The path became unusable after a local network change.
-1095    UnusableAfterNetworkChange,
-1096    /// The path was opened in a NAT traversal round which was terminated.
-1097    NatTraversalRoundEnded,
-1098    /// The remote closed the path.
-1099    RemoteAbandoned {
-1100        /// The error that was sent with the abandon frame.
-1101        error_code: VarInt,
-1102    },
-1103}
-1104
-1105impl PathAbandonReason {
-1106    /// Whether this abandon was initiated by the remote peer.
-1107    pub(crate) fn is_remote(&self) -> bool {
-1108        matches!(self, Self::RemoteAbandoned { .. })
-1109    }
-1110
-1111    /// Returns the error code to send with a PATH_ABANDON frame.
-1112    pub(crate) fn error_code(&self) -> TransportErrorCode {
-1113        match self {
-1114            Self::ApplicationClosed { error_code } => (*error_code).into(),
-1115            Self::NatTraversalRoundEnded => TransportErrorCode::APPLICATION_ABANDON_PATH,
-1116            Self::ValidationFailed | Self::TimedOut | Self::UnusableAfterNetworkChange => {
-1117                TransportErrorCode::PATH_UNSTABLE_OR_POOR
-1118            }
-1119            Self::RemoteAbandoned { error_code } => (*error_code).into(),
-1120        }
-1121    }
-1122}
-1123
-1124/// Error from setting path status
-1125#[derive(Debug, Error, Clone, PartialEq, Eq)]
-1126pub enum SetPathStatusError {
-1127    /// Error indicating that a path has not been opened or has already been abandoned
-1128    #[error("closed path")]
-1129    ClosedPath,
-1130    /// Error indicating that this operation requires multipath to be negotiated whereas it hasn't been
-1131    #[error("multipath not negotiated")]
-1132    MultipathNotNegotiated,
-1133}
-1134
-1135/// Error indicating that a path has not been opened or has already been abandoned
-1136#[derive(Debug, Default, Error, Clone, PartialEq, Eq)]
-1137#[error("closed path")]
-1138pub struct ClosedPath {
-1139    pub(super) _private: (),
-1140}
-1141
-1142#[cfg(test)]
-1143mod tests {
-1144    use super::*;
-1145
-1146    #[test]
-1147    fn test_path_id_saturating_add() {
-1148        // add within range behaves normally
-1149        let large: PathId = u16::MAX.into();
-1150        let next = u32::from(u16::MAX) + 1;
-1151        assert_eq!(large.saturating_add(1u8), PathId::from(next));
-1152
-1153        // outside range saturates
-1154        assert_eq!(PathId::MAX.saturating_add(1u8), PathId::MAX)
-1155    }
-1156}

\ No newline at end of file
+1047        /// The final path stats, they are no longer available via [`Connection::stats`]
+1048        ///
+1049        /// [`Connection::stats`]: super::Connection::stats
+1050        path_stats: Box<PathStats>,
+1051    },
+1052    /// The remote changed the status of the path
+1053    ///
+1054    /// The local status is not changed because of this event. It is up to the application
+1055    /// to update the local status, which is used for packet scheduling, when the remote
+1056    /// changes the status.
+1057    RemoteStatus {
+1058        /// Path which has changed status
+1059        id: PathId,
+1060        /// The new status set by the remote
+1061        status: PathStatus,
+1062    },
+1063    /// Received an observation of our external address from the peer.
+1064    ObservedAddr {
+1065        /// Path over which the observed address was reported, [`PathId::ZERO`] when multipath is
+1066        /// not negotiated
+1067        id: PathId,
+1068        /// The address observed by the remote over this path
+1069        addr: SocketAddr,
+1070    },
+1071}
+1072
+1073/// Reason for why a path was abandoned.
+1074#[derive(Debug, Clone, Eq, PartialEq)]
+1075pub enum PathAbandonReason {
+1076    /// The path was closed locally by the application.
+1077    ApplicationClosed {
+1078        /// The error code to be sent with the abandon frame.
+1079        error_code: VarInt,
+1080    },
+1081    /// We didn't receive a path response in time after opening this path.
+1082    ValidationFailed,
+1083    /// We didn't receive any data from the remote within the path's idle timeout.
+1084    TimedOut,
+1085    /// The path became unusable after a local network change.
+1086    UnusableAfterNetworkChange,
+1087    /// The path was opened in a NAT traversal round which was terminated.
+1088    NatTraversalRoundEnded,
+1089    /// The remote closed the path.
+1090    RemoteAbandoned {
+1091        /// The error that was sent with the abandon frame.
+1092        error_code: VarInt,
+1093    },
+1094}
+1095
+1096impl PathAbandonReason {
+1097    /// Whether this abandon was initiated by the remote peer.
+1098    pub(crate) fn is_remote(&self) -> bool {
+1099        matches!(self, Self::RemoteAbandoned { .. })
+1100    }
+1101
+1102    /// Returns the error code to send with a PATH_ABANDON frame.
+1103    pub(crate) fn error_code(&self) -> TransportErrorCode {
+1104        match self {
+1105            Self::ApplicationClosed { error_code } => (*error_code).into(),
+1106            Self::NatTraversalRoundEnded => TransportErrorCode::APPLICATION_ABANDON_PATH,
+1107            Self::ValidationFailed | Self::TimedOut | Self::UnusableAfterNetworkChange => {
+1108                TransportErrorCode::PATH_UNSTABLE_OR_POOR
+1109            }
+1110            Self::RemoteAbandoned { error_code } => (*error_code).into(),
+1111        }
+1112    }
+1113}
+1114
+1115/// Error from setting path status
+1116#[derive(Debug, Error, Clone, PartialEq, Eq)]
+1117pub enum SetPathStatusError {
+1118    /// Error indicating that a path has not been opened or has already been abandoned
+1119    #[error("closed path")]
+1120    ClosedPath,
+1121    /// Error indicating that this operation requires multipath to be negotiated whereas it hasn't been
+1122    #[error("multipath not negotiated")]
+1123    MultipathNotNegotiated,
+1124}
+1125
+1126/// Error indicating that a path has not been opened or has already been abandoned
+1127#[derive(Debug, Default, Error, Clone, PartialEq, Eq)]
+1128#[error("closed path")]
+1129pub struct ClosedPath {
+1130    pub(super) _private: (),
+1131}
+1132
+1133#[cfg(test)]
+1134mod tests {
+1135    use super::*;
+1136
+1137    #[test]
+1138    fn test_path_id_saturating_add() {
+1139        // add within range behaves normally
+1140        let large: PathId = u16::MAX.into();
+1141        let next = u32::from(u16::MAX) + 1;
+1142        assert_eq!(large.saturating_add(1u8), PathId::from(next));
+1143
+1144        // outside range saturates
+1145        assert_eq!(PathId::MAX.saturating_add(1u8), PathId::MAX)
+1146    }
+1147}

\ No newline at end of file
diff --git a/pr/616/docs/src/noq_proto/connection/spaces.rs.html b/pr/616/docs/src/noq_proto/connection/spaces.rs.html
index 5d65aedc1..3f3a3fa55 100644
--- a/pr/616/docs/src/noq_proto/connection/spaces.rs.html
+++ b/pr/616/docs/src/noq_proto/connection/spaces.rs.html
@@ -2,1543 +2,1594 @@
 2    cmp,
 3    collections::{BTreeMap, BTreeSet, VecDeque},
 4    mem,
-5    net::IpAddr,
-6    ops::{Bound, Index, IndexMut},
-7};
-8
-9use rand::{CryptoRng, RngExt};
-10use rustc_hash::{FxHashMap, FxHashSet};
-11use sorted_index_buffer::SortedIndexBuffer;
-12use tracing::trace;
-13
-14use super::PathId;
-15use crate::{
-16    Dir, Duration, FourTuple, Instant, StreamId, TransportError, TransportErrorCode, VarInt,
-17    connection::StreamsState,
-18    frame::{self, AddAddress, RemoveAddress},
-19    packet::SpaceId,
-20    range_set::ArrayRangeSet,
-21    shared::IssuedCid,
-22};
-23
-24pub(super) struct PacketSpace {
-25    /// Data to send
-26    pub(super) pending: Retransmits,
-27
-28    /// Multipath packet number spaces
-29    ///
-30    /// Each [`PathId`] has it's own [`PacketNumberSpace`].  Only the [`SpaceId::Data`] can
-31    /// have multiple packet number spaces, the other spaces only have a number space for
-32    /// `PathId::ZERO`, which is populated at creation.
-33    pub(super) number_spaces: BTreeMap<PathId, PacketNumberSpace>,
-34}
-35
-36impl PacketSpace {
-37    pub(super) fn new(now: Instant, space: SpaceId, rng: &mut (impl CryptoRng + ?Sized)) -> Self {
-38        let number_space_0 = PacketNumberSpace::new(now, space, rng);
-39        Self {
-40            pending: Retransmits::default(),
-41            number_spaces: BTreeMap::from([(PathId::ZERO, number_space_0)]),
-42        }
-43    }
-44
-45    #[cfg(test)]
-46    pub(super) fn new_deterministic(now: Instant, space: SpaceId) -> Self {
-47        let number_space_0 = PacketNumberSpace::new_deterministic(now, space);
-48        Self {
-49            pending: Retransmits::default(),
-50            number_spaces: BTreeMap::from([(PathId::ZERO, number_space_0)]),
-51        }
-52    }
-53
-54    /// Returns the [`PacketNumberSpace`] for a path
-55    ///
-56    /// When multipath is disabled use [`PathId::ZERO`].
-57    pub(super) fn path_space(&self, path_id: PathId) -> Option<&PacketNumberSpace> {
-58        self.number_spaces.get(&path_id)
-59    }
-60
-61    /// Returns a mutable reference to the [`PacketNumberSpace`] for a path
-62    ///
-63    /// When multipath is disabled use [`PathId::ZERO`].
-64    pub(super) fn path_space_mut(&mut self, path_id: PathId) -> Option<&mut PacketNumberSpace> {
-65        self.number_spaces.get_mut(&path_id)
-66    }
-67
-68    /// Returns the [`PacketNumberSpace`] for a path
-69    ///
-70    /// When multipath is disabled use `PathId::ZERO`.
-71    // TODO(flub): Note that this only exists as `&mut self` because it creates a new
-72    //    [`PacketNumberSpace`] if one is not yet available for a path.  This forces a few
-73    //    more `&mut` references to users than strictly needed.  An alternative would be to
-74    //    return an Option but that would need to be handled for all callers.  This could be
-75    //    worth exploring once we have all the main multipath bits fitted.
-76    pub(super) fn for_path(&mut self, path: PathId) -> &mut PacketNumberSpace {
-77        self.number_spaces
-78            .get_mut(&path)
-79            .unwrap_or_else(|| panic!("PacketNumberSpace missing for {path}"))
-80    }
-81
-82    pub(super) fn iter_paths_mut(&mut self) -> impl Iterator<Item = &mut PacketNumberSpace> {
-83        self.number_spaces.values_mut()
-84    }
-85
-86    /// Queue data for a tail loss probe (or anti-amplification deadlock prevention) packet
-87    ///
-88    /// Probes are sent similarly to normal packets when an expected ACK has not arrived. We never
-89    /// deem a packet lost until we receive an ACK that should have included it, but if a trailing
-90    /// run of packets (or their ACKs) are lost, this might not happen in a timely fashion. We send
-91    /// probe packets to force an ACK, and exempt them from congestion control to prevent a deadlock
-92    /// when the congestion window is filled with lost tail packets.
-93    ///
-94    /// We prefer to send new data, to make the most efficient use of bandwidth. If there's no data
-95    /// waiting to be sent, then we retransmit in-flight data to reduce odds of loss. If there's no
-96    /// in-flight data either, we're probably a client guarding against a handshake
-97    /// anti-amplification deadlock and we just make something up.
-98    pub(super) fn queue_tail_loss_probe(
-99        &mut self,
-100        path_id: PathId,
-101        request_immediate_ack: bool,
-102        streams: &StreamsState,
-103    ) {
-104        if request_immediate_ack {
-105            // The probe should be ACKed without delay (should only be used in the Data space and
-106            // when the peer supports the acknowledgement frequency extension)
-107            self.for_path(path_id).immediate_ack_pending = true;
-108        }
-109
-110        // We prefer to send new data to make most efficient use of bandwidth.
-111        if !self.pending.is_empty(streams) {
-112            // There's real data to send here, no need to make something up
-113            return;
-114        }
-115
-116        // Retransmit data from the oldest in-flight data from any path
-117        for packet in self
-118            .number_spaces
-119            .values_mut()
-120            .flat_map(|s| s.sent_packets.values_mut())
-121        {
-122            if !packet.retransmits.is_empty(streams) {
-123                // Remove retransmitted data from the old packet so we don't end up retransmitting
-124                // it *again* even if the copy we're sending now gets acknowledged.
-125                self.pending |= mem::take(&mut packet.retransmits);
-126                return;
-127            }
-128        }
-129
-130        // Nothing new to send and nothing to retransmit, so fall back on a ping. This should only
-131        // happen in rare cases during the handshake when the server becomes blocked by
-132        // anti-amplification.
-133        if !self.for_path(path_id).immediate_ack_pending {
-134            self.for_path(path_id).ping_pending = true;
-135        }
-136    }
-137
-138    /// Whether there is anything to send in this space
-139    ///
-140    /// For the data space [`Connection::can_send_1rtt`] also needs to be consulted. Prefer
-141    /// to use [`Connection::space_can_send`] which handles this.
-142    ///
-143    /// [`Connection::can_send_1rtt`]: super::Connection::can_send_1rtt
-144    /// [`Connection::space_can_send`]: super::Connection::space_can_send
-145    pub(super) fn can_send(&self, path_id: PathId, streams: &StreamsState) -> SendableFrames {
-146        let acks = self
-147            .number_spaces
-148            .values()
-149            .any(|pns| pns.pending_acks.can_send());
-150        let space_specific = self
-151            .number_spaces
-152            .get(&path_id)
-153            .is_some_and(|s| s.ping_pending || s.immediate_ack_pending);
-154        let other = !self.pending.is_empty(streams);
-155        SendableFrames {
-156            acks,
-157            close: false,
-158            space_specific,
-159            other,
-160        }
-161    }
-162}
-163
-164impl Index<SpaceId> for [PacketSpace; 3] {
-165    type Output = PacketSpace;
-166    fn index(&self, space: SpaceId) -> &PacketSpace {
-167        &self.as_ref()[space as usize]
-168    }
-169}
-170
-171impl IndexMut<SpaceId> for [PacketSpace; 3] {
-172    fn index_mut(&mut self, space: SpaceId) -> &mut PacketSpace {
-173        &mut self.as_mut()[space as usize]
-174    }
-175}
-176
-177/// The three QUIC packet number space kinds
-178///
-179/// Unlike [`SpaceId`], this always has exactly three variants — it represents the
-180/// encryption level / space kind, not a specific packet number space identity.
-181#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
-182pub(crate) enum SpaceKind {
-183    /// Initial packets (client and server).
-184    Initial = 0,
-185    /// Handshake packets.
-186    Handshake = 1,
-187    /// Data (1-RTT and 0-RTT)
-188    Data = 2,
-189}
-190
-191impl SpaceKind {
-192    /// Returns the encryption level for this space kind.
-193    pub(crate) fn encryption_level(self) -> super::EncryptionLevel {
-194        match self {
-195            Self::Initial => super::EncryptionLevel::Initial,
-196            Self::Handshake => super::EncryptionLevel::Handshake,
-197            Self::Data => super::EncryptionLevel::OneRtt,
-198        }
-199    }
-200}
-201
-202impl Index<SpaceKind> for [PacketSpace; 3] {
-203    type Output = PacketSpace;
-204    fn index(&self, space: SpaceKind) -> &PacketSpace {
-205        &self.as_ref()[space as usize]
-206    }
-207}
-208
-209impl IndexMut<SpaceKind> for [PacketSpace; 3] {
-210    fn index_mut(&mut self, space: SpaceKind) -> &mut PacketSpace {
-211        &mut self.as_mut()[space as usize]
-212    }
-213}
-214
-215/// The state of a single packet number space.
-216///
-217/// In RFC9000 there are 3 packet number spaces: Initial, Handshake and Data. In QUIC
-218/// Multipath there are multiple packet number spaces for Data, each identified by a
-219/// [`PathId`].
-220///
-221/// This contains the state for a packet number space which is not specific to the 4-tuple
-222/// this space is currently using. The 4-tuple specific state, like congestion controller,
-223/// pacing, ECN, MTU etc, is stored in [`PathData`].
-224///
-225/// Note that the `Initial`, `Handshake` and `Data(PathId(0))` space all share the same
-226/// [`PathData`].
-227///
-228/// You should access this via [`PacketSpace::for_path`].
-229///
-230/// [`PathData`]: super::paths::PathData
-231pub(super) struct PacketNumberSpace {
-232    /// Highest received packet number, if any
-233    pub(super) largest_received_packet_number: Option<u64>,
-234    /// The packet number of the next packet that will be sent, if any. In the Data space, the
-235    /// packet number stored here is sometimes skipped by [`PacketNumberFilter`] logic.
-236    pub(super) next_packet_number: u64,
-237    /// The largest packet number the remote peer acknowledged in an ACK frame.
-238    pub(super) largest_acked_packet_pn: Option<u64>,
-239    pub(super) largest_acked_packet_send_time: Instant,
-240    /// The highest-numbered ACK-eliciting packet we've sent
-241    pub(super) largest_ack_eliciting_sent: u64,
-242    /// Number of packets in `sent_packets` with numbers above `largest_ack_eliciting_sent`
-243    pub(super) unacked_non_ack_eliciting_tail: u64,
-244    /// Transmitted but not acked
-245    // We use a BTreeMap here so we can efficiently query by range on ACK and for loss detection
-246    pub(super) sent_packets: SortedIndexBuffer<SentPacket>,
-247    /// Packets that were deemed lost
-248    // Older packets are regularly removed in `Connection::drain_lost_packets`.
-249    pub(super) lost_packets: SortedIndexBuffer<LostPacket>,
-250    /// Number of explicit congestion notification codepoints seen on incoming packets
-251    pub(super) ecn_counters: frame::EcnCounts,
-252    /// Recent ECN counters sent by the peer in ACK frames
-253    ///
-254    /// Updated (and inspected) whenever we receive an ACK with a new highest acked packet
-255    /// number. Stored per-space to simplify verification, which would otherwise have difficulty
-256    /// distinguishing between ECN bleaching and counts having been updated by a near-simultaneous
-257    /// ACK already processed in another space.
-258    pub(super) ecn_feedback: frame::EcnCounts,
-259    /// A PING frame needs to be sent on this path
-260    pub(super) ping_pending: bool,
-261    /// An IMMEDIATE_ACK (draft-ietf-quic-ack-frequency) frame needs to be sent on this path
-262    pub(super) immediate_ack_pending: bool,
-263    /// Packet deduplicator
-264    pub(super) dedup: Dedup,
-265    /// Packet numbers to acknowledge
-266    pub(super) pending_acks: PendingAcks,
-267
-268    //
-269    // Loss Detection
-270    //
-271    /// The time the most recently sent retransmittable packet was sent.
-272    pub(super) time_of_last_ack_eliciting_packet: Option<Instant>,
-273    /// Earliest time when we might declare a packet lost.
-274    ///
-275    /// The time at which the earliest sent packet in this space will be considered lost
-276    /// based on exceeding the reordering window in time. Only set for packets numbered
-277    /// prior to a packet that has been acknowledged.
-278    pub(super) loss_time: Option<Instant>,
-279    /// Number of tail loss probes to send
-280    pub(super) loss_probes: u32,
-281
-282    /// Packet numbers to skip, only used in the data package space.
-283    pn_filter: Option<PacketNumberFilter>,
-284}
-285
-286impl PacketNumberSpace {
-287    pub(super) fn new(now: Instant, space: SpaceId, rng: &mut (impl CryptoRng + ?Sized)) -> Self {
-288        let pn_filter = match space {
-289            SpaceId::Initial | SpaceId::Handshake => None,
-290            SpaceId::Data => Some(PacketNumberFilter::new(rng)),
-291        };
-292        Self {
-293            largest_received_packet_number: None,
-294            next_packet_number: 0,
-295            largest_acked_packet_pn: None,
-296            largest_acked_packet_send_time: now,
-297            largest_ack_eliciting_sent: 0,
-298            unacked_non_ack_eliciting_tail: 0,
-299            sent_packets: SortedIndexBuffer::new(),
-300            lost_packets: SortedIndexBuffer::new(),
-301            ecn_counters: frame::EcnCounts::ZERO,
-302            ecn_feedback: frame::EcnCounts::ZERO,
-303            ping_pending: false,
-304            immediate_ack_pending: false,
-305            dedup: Default::default(),
-306            pending_acks: PendingAcks::new(),
-307            time_of_last_ack_eliciting_packet: None,
-308            loss_time: None,
-309            loss_probes: 0,
-310            pn_filter,
-311        }
-312    }
-313
-314    #[cfg(test)]
-315    fn new_deterministic(now: Instant, space: SpaceId) -> Self {
-316        let pn_filter = match space {
-317            SpaceId::Initial | SpaceId::Handshake => None,
-318            SpaceId::Data => Some(PacketNumberFilter::disabled()),
-319        };
-320        Self {
-321            largest_received_packet_number: None,
-322            next_packet_number: 0,
-323            largest_acked_packet_pn: None,
-324            largest_acked_packet_send_time: now,
-325            largest_ack_eliciting_sent: 0,
-326            unacked_non_ack_eliciting_tail: 0,
-327            sent_packets: SortedIndexBuffer::new(),
-328            lost_packets: SortedIndexBuffer::new(),
-329            ecn_counters: frame::EcnCounts::ZERO,
-330            ecn_feedback: frame::EcnCounts::ZERO,
-331            ping_pending: false,
-332            immediate_ack_pending: false,
-333            dedup: Default::default(),
-334            pending_acks: PendingAcks::new(),
-335            time_of_last_ack_eliciting_packet: None,
-336            loss_time: None,
-337            loss_probes: 0,
-338            pn_filter,
-339        }
-340    }
-341
-342    /// Get the next outgoing packet number in this space
-343    ///
-344    /// In the Data space, the connection's [`PacketNumberFilter`] must be used rather than calling
-345    /// this directly.
-346    pub(super) fn get_tx_number(&mut self, rng: &mut (impl CryptoRng + ?Sized)) -> u64 {
-347        // TODO: Handle packet number overflow gracefully
-348        assert!(self.next_packet_number < 2u64.pow(62));
-349        let mut pn = self.next_packet_number;
-350        self.next_packet_number += 1;
-351
-352        // Skip this number if the filter says so, only enabled in the data space
-353        if let Some(ref mut filter) = self.pn_filter
-354            && filter.skip_pn(pn, rng)
-355        {
-356            pn = self.next_packet_number;
-357            self.next_packet_number += 1;
-358        }
-359        pn
-360    }
-361
-362    pub(super) fn peek_tx_number(&mut self) -> u64 {
-363        let pn = self.next_packet_number;
-364        if let Some(ref filter) = self.pn_filter
-365            && pn == filter.next_skipped_packet_number
-366        {
-367            return pn + 1;
-368        }
-369        pn
-370    }
-371
-372    /// Checks whether a skipped packet number was ACKed.
-373    pub(super) fn check_ack(&self, range: std::ops::Range<u64>) -> Result<(), TransportError> {
-374        if let Some(ref filter) = self.pn_filter
-375            && filter
-376                .prev_skipped_packet_number
-377                .is_some_and(|pn| range.contains(&pn))
-378        {
-379            return Err(TransportError::PROTOCOL_VIOLATION("unsent packet acked"));
-380        }
-381        Ok(())
-382    }
-383
-384    /// Verifies sanity of an ECN block and returns whether congestion was encountered.
-385    pub(super) fn detect_ecn(
-386        &mut self,
-387        newly_acked: u64,
-388        ecn: frame::EcnCounts,
-389    ) -> Result<bool, &'static str> {
-390        let ect0_increase = ecn
-391            .ect0
-392            .checked_sub(self.ecn_feedback.ect0)
-393            .ok_or("peer ECT(0) count regression")?;
-394        let ect1_increase = ecn
-395            .ect1
-396            .checked_sub(self.ecn_feedback.ect1)
-397            .ok_or("peer ECT(1) count regression")?;
-398        let ce_increase = ecn
-399            .ce
-400            .checked_sub(self.ecn_feedback.ce)
-401            .ok_or("peer CE count regression")?;
-402        let total_increase = ect0_increase + ect1_increase + ce_increase;
-403        if total_increase < newly_acked {
-404            return Err("ECN bleaching");
-405        }
-406        if (ect0_increase + ce_increase) < newly_acked || ect1_increase != 0 {
-407            return Err("ECN corruption");
-408        }
-409        // If total_increase > newly_acked (which happens when ACKs are lost), this is required by
-410        // the draft so that long-term drift does not occur. If =, then the only question is whether
-411        // to count CE packets as CE or ECT0. Recording them as CE is more consistent and keeps the
-412        // congestion check obvious.
-413        self.ecn_feedback = ecn;
-414        Ok(ce_increase != 0)
-415    }
-416
-417    /// Stop tracking sent packet `number`, and return what we knew about it
-418    pub(super) fn take(&mut self, number: u64) -> Option<SentPacket> {
-419        let packet = self.sent_packets.remove(number)?;
-420        if !packet.ack_eliciting && number > self.largest_ack_eliciting_sent {
-421            self.unacked_non_ack_eliciting_tail =
-422                self.unacked_non_ack_eliciting_tail.checked_sub(1).unwrap();
-423        }
-424        Some(packet)
-425    }
-426
-427    /// May return a packet that should be forgotten
-428    pub(super) fn sent(&mut self, number: u64, packet: SentPacket) -> Option<SentPacket> {
-429        // Retain state for at most this many non-ACK-eliciting packets sent after the most recently
-430        // sent ACK-eliciting packet. We're never guaranteed to receive an ACK for those, and we
-431        // can't judge them as lost without an ACK, so to limit memory in applications which receive
-432        // packets but don't send ACK-eliciting data for long periods use we must eventually start
-433        // forgetting about them, although it might also be reasonable to just kill the connection
-434        // due to weird peer behavior.
-435        const MAX_UNACKED_NON_ACK_ELICTING_TAIL: u64 = 1_000;
-436
-437        let mut forgotten = None;
-438        if packet.ack_eliciting {
-439            self.unacked_non_ack_eliciting_tail = 0;
-440            self.largest_ack_eliciting_sent = number;
-441        } else if self.unacked_non_ack_eliciting_tail > MAX_UNACKED_NON_ACK_ELICTING_TAIL {
-442            let oldest_after_ack_eliciting = self
-443                .sent_packets
-444                .keys_range((
-445                    Bound::Excluded(self.largest_ack_eliciting_sent),
-446                    Bound::Unbounded,
-447                ))
-448                .next()
-449                .unwrap();
-450            // Per https://www.rfc-editor.org/rfc/rfc9000.html#name-frames-and-frame-types,
-451            // non-ACK-eliciting packets must only contain PADDING, ACK, and CONNECTION_CLOSE
-452            // frames, which require no special handling on ACK or loss beyond removal from
-453            // in-flight counters if padded.
-454            let packet = self
-455                .sent_packets
-456                .remove(oldest_after_ack_eliciting)
-457                .unwrap();
-458            debug_assert!(!packet.ack_eliciting);
-459            forgotten = Some(packet);
-460        } else {
-461            self.unacked_non_ack_eliciting_tail += 1;
-462        }
-463
-464        self.sent_packets.insert(number, packet);
-465        forgotten
-466    }
-467
-468    /// Whether any congestion-controlled packets in this space are not yet acknowledged or lost
-469    pub(super) fn has_in_flight(&self) -> bool {
-470        // The number of non-congestion-controlled (i.e. size == 0) packets in flight at a time
-471        // should be small, since otherwise congestion control wouldn't be effective. Therefore,
-472        // this shouldn't need to visit many packets before finishing one way or another.
-473        self.sent_packets.values().any(|x| x.size != 0)
-474    }
-475}
-476
-477/// Represents one or more packets subject to retransmission
-478#[derive(Debug, Clone)]
-479pub(super) struct SentPacket {
-480    /// [`PathData::generation`](super::PathData::generation) of the path on which this packet was sent
-481    pub(super) path_generation: u64,
-482    /// The time the packet was sent.
-483    pub(super) time_sent: Instant,
-484    /// The number of bytes sent in the packet, not including UDP or IP overhead, but including QUIC
-485    /// framing overhead. Zero if this packet is not counted towards congestion control, i.e. not an
-486    /// "in flight" packet.
-487    pub(super) size: u16,
-488    /// Whether an acknowledgement is expected directly in response to this packet.
-489    pub(super) ack_eliciting: bool,
-490    /// The largest packet number acknowledged by this packet
-491    pub(super) largest_acked: FxHashMap<PathId, u64>,
-492    /// Data which needs to be retransmitted in case the packet is lost.
-493    /// The data is boxed to minimize `SentPacket` size for the typical case of
-494    /// packets only containing ACKs and STREAM frames.
-495    pub(super) retransmits: ThinRetransmits,
-496    /// Metadata for stream frames in a packet
-497    ///
-498    /// The actual application data is stored with the stream state.
-499    pub(super) stream_frames: frame::StreamMetaVec,
-500}
-501
-502/// Represents one or more packets that are deemed lost.
-503#[derive(Debug)]
-504pub(super) struct LostPacket {
-505    /// The time the packet was sent.
-506    pub(super) time_sent: Instant,
-507}
-508
-509/// Retransmittable data queue
-510#[allow(unreachable_pub)] // fuzzing only
-511#[derive(Debug, Default, Clone)]
-512pub struct Retransmits {
-513    pub(super) max_data: bool,
-514    pub(super) max_stream_id: [bool; 2],
-515    pub(super) streams_blocked: [bool; 2],
-516    pub(super) reset_stream: Vec<(StreamId, VarInt)>,
-517    pub(super) stop_sending: Vec<frame::StopSending>,
-518    pub(super) max_stream_data: FxHashSet<StreamId>,
-519    pub(super) crypto: VecDeque<frame::Crypto>,
-520    pub(super) new_cids: PendingNewCids,
-521    pub(super) retire_cids: Vec<(PathId, u64)>,
-522    pub(super) ack_frequency: bool,
-523    pub(super) handshake_done: bool,
-524    pub(super) observed_addr: bool,
-525    /// Whether we should inform the peer we will allow higher [`PathId`]s.
-526    pub(super) max_path_id: bool,
-527    /// Whether we should inform the peer that their max [`PathId`] is blocking our attempt to open
-528    /// new paths.
-529    // TODO(@divma): we need logic to prevent sending this more than once after being ack-d once
-530    pub(super) paths_blocked: bool,
-531    /// For each enqueued NEW_TOKEN frame, a copy of the path's remote address
-532    ///
-533    /// There are 2 reasons this is unusual:
-534    ///
-535    /// - If the path changes, NEW_TOKEN frames bound for the old path are not retransmitted on the
-536    ///   new path. That is why this field stores the remote address: so that ones for old paths
-537    ///   can be filtered out.
-538    /// - If a token is lost, a new randomly generated token is re-transmitted, rather than the
-539    ///   original. This is so that if both transmissions are received, the client won't risk
-540    ///   sending the same token twice. That is why this field does _not_ store any actual token.
-541    ///
-542    /// It is true that a QUIC endpoint will only want to effectively have NEW_TOKEN frames
-543    /// enqueued for its current path at a given point in time. Based on that, we could conceivably
-544    /// change this from a vector to an `Option<(FourTuple, usize)>` or just a `usize` or
-545    /// something. However, due to the architecture of noq, it is considerably simpler to not do
-546    /// that; consider what such a change would mean for implementing `BitOrAssign` on Self.
-547    pub(super) new_tokens: Vec<FourTuple>,
-548    /// Paths which need to be abandoned
-549    pub(super) path_abandon: BTreeMap<PathId, TransportErrorCode>,
-550    /// If a [`frame::PathStatusAvailable`] and [`frame::PathStatusBackup`] need to be sent for a path
-551    pub(super) path_status: BTreeSet<PathId>,
-552    /// If a PATH_CIDS_BLOCKED frame needs to be sent for a path
-553    pub(super) path_cids_blocked: BTreeSet<PathId>,
-554
-555    // Nat traversal data
-556    /// Addresses to report in `ADD_ADDRESS` frames
-557    pub(super) add_address: BTreeSet<AddAddress>,
-558    /// Address IDs to remove in `REMOVE_ADDRESS` frames
-559    pub(super) remove_address: BTreeSet<RemoveAddress>,
-560    /// Round and local addresses to advertise in `REACH_OUT` frames
-561    pub(super) reach_out: Option<(VarInt, FxHashSet<(IpAddr, u16)>)>,
-562}
-563
-564impl Retransmits {
-565    pub(super) fn is_empty(&self, streams: &StreamsState) -> bool {
-566        let Self {
-567            max_data,
-568            max_stream_id,
-569            streams_blocked,
-570            reset_stream,
-571            stop_sending,
-572            max_stream_data,
-573            crypto,
-574            new_cids,
-575            retire_cids,
-576            ack_frequency,
-577            handshake_done,
-578            observed_addr,
-579            max_path_id,
-580            paths_blocked,
-581            new_tokens,
-582            path_abandon,
-583            path_status,
-584            path_cids_blocked,
-585            add_address,
-586            remove_address,
-587            reach_out,
-588        } = &self;
-589        !max_data
-590            && !max_stream_id.iter().any(|x| *x)
-591            && !streams_blocked.iter().any(|x| *x)
-592            && reset_stream.is_empty()
-593            && stop_sending.is_empty()
-594            && max_stream_data
-595                .iter()
-596                .all(|&id| !streams.can_send_flow_control(id))
-597            && crypto.is_empty()
-598            && new_cids.is_empty()
-599            && retire_cids.is_empty()
-600            && !ack_frequency
-601            && !handshake_done
-602            && !observed_addr
-603            && !max_path_id
-604            && !paths_blocked
-605            && new_tokens.is_empty()
-606            && path_abandon.is_empty()
-607            && path_status.is_empty()
-608            && path_cids_blocked.is_empty()
-609            && add_address.is_empty()
-610            && remove_address.is_empty()
-611            && reach_out.is_none()
-612    }
-613}
-614
-615impl ::std::ops::BitOrAssign for Retransmits {
-616    fn bitor_assign(&mut self, rhs: Self) {
-617        let Self {
-618            max_data,
-619            max_stream_id,
-620            streams_blocked,
-621            reset_stream,
-622            stop_sending,
-623            max_stream_data,
-624            crypto,
-625            new_cids,
-626            retire_cids,
-627            ack_frequency,
-628            handshake_done,
-629            observed_addr,
-630            max_path_id,
-631            paths_blocked,
-632            new_tokens,
-633            mut path_abandon,
-634            mut path_status,
-635            mut path_cids_blocked,
-636            add_address,
-637            remove_address,
-638            reach_out,
-639        } = rhs;
-640
-641        // We reduce in-stream head-of-line blocking by queueing retransmits before other data for
-642        // STREAM and CRYPTO frames.
-643        self.max_data |= max_data;
-644        for dir in Dir::iter() {
-645            self.max_stream_id[dir as usize] |= max_stream_id[dir as usize];
-646            self.streams_blocked[dir as usize] |= streams_blocked[dir as usize];
-647        }
-648        self.reset_stream.extend_from_slice(&reset_stream);
-649        self.stop_sending.extend_from_slice(&stop_sending);
-650        self.max_stream_data.extend(&max_stream_data);
-651        for crypto in crypto.into_iter().rev() {
-652            self.crypto.push_front(crypto);
-653        }
-654        self.new_cids.extend(&new_cids);
-655        self.retire_cids.extend(retire_cids);
-656        self.ack_frequency |= ack_frequency;
-657        self.handshake_done |= handshake_done;
-658        self.observed_addr |= observed_addr;
-659        self.max_path_id |= max_path_id;
-660        self.paths_blocked |= paths_blocked;
-661        self.new_tokens.extend_from_slice(&new_tokens);
-662        self.path_abandon.append(&mut path_abandon);
-663        self.path_status.append(&mut path_status);
-664        self.path_cids_blocked.append(&mut path_cids_blocked);
-665        self.add_address.extend(add_address.iter().copied());
-666        self.remove_address.extend(remove_address.iter().copied());
-667        if let Some((rhs_round, rhs_addrs)) = reach_out {
-668            match self.reach_out.as_mut() {
-669                // Use RHS if there is no recorded round.
-670                None => self.reach_out = Some((rhs_round, rhs_addrs)),
-671                // Use RHS if newer.
-672                Some((lhs_round, _lhs_addrs)) if rhs_round > *lhs_round => {
-673                    self.reach_out = Some((rhs_round, rhs_addrs));
-674                }
-675                // If both rounds are the same, merge them.
-676                Some((lhs_round, lhs_addrs)) if rhs_round == *lhs_round => {
-677                    lhs_addrs.extend(rhs_addrs);
-678                }
-679                // LHS round is newer, ignore RHS
-680                Some(_) => {}
-681            }
-682        }
-683    }
-684}
-685
-686impl ::std::ops::BitOrAssign<ThinRetransmits> for Retransmits {
-687    fn bitor_assign(&mut self, rhs: ThinRetransmits) {
-688        let ThinRetransmits { retransmits } = rhs;
-689        if let Some(retransmits) = retransmits {
-690            self.bitor_assign(*retransmits)
-691        }
-692    }
-693}
-694
-695impl ::std::iter::FromIterator<Self> for Retransmits {
-696    fn from_iter<T>(iter: T) -> Self
-697    where
-698        T: IntoIterator<Item = Self>,
-699    {
-700        let mut result = Self::default();
-701        for packet in iter {
-702            result |= packet;
-703        }
-704        result
-705    }
-706}
-707
-708/// The queue of new CIDs to be transmitted to the peer.
-709///
-710/// This queue is always sorted, so that popping off the last item is always the lowest
-711/// sequence number of the lowest path ID. Which is the CID you want to be issued next.
-712///
-713/// This is but a newtype over a `Vec` to enforce the sorted invariant.
-714#[derive(Clone, Debug, Default)]
-715pub(super) struct PendingNewCids {
-716    /// The CIDs themselves.
-717    cids: Vec<IssuedCid>,
-718    /// Whether [`Self::cids`] is sorted or not.
-719    sorted: bool,
-720}
+5    ops::{Bound, Index, IndexMut},
+6};
+7
+8use rand::{CryptoRng, RngExt};
+9use rustc_hash::{FxHashMap, FxHashSet};
+10use sorted_index_buffer::SortedIndexBuffer;
+11use tracing::trace;
+12
+13use super::PathId;
+14use crate::{
+15    Dir, Duration, FourTuple, Instant, StreamId, TransportError, TransportErrorCode, VarInt,
+16    connection::StreamsState,
+17    frame::{self, AddAddress, RemoveAddress},
+18    packet::SpaceId,
+19    range_set::ArrayRangeSet,
+20    shared::IssuedCid,
+21};
+22
+23pub(super) struct PacketSpace {
+24    /// Data to send
+25    pub(super) pending: Retransmits,
+26
+27    /// Multipath packet number spaces
+28    ///
+29    /// Each [`PathId`] has it's own [`PacketNumberSpace`].  Only the [`SpaceId::Data`] can
+30    /// have multiple packet number spaces, the other spaces only have a number space for
+31    /// `PathId::ZERO`, which is populated at creation.
+32    pub(super) number_spaces: BTreeMap<PathId, PacketNumberSpace>,
+33}
+34
+35impl PacketSpace {
+36    pub(super) fn new(now: Instant, space: SpaceId, rng: &mut (impl CryptoRng + ?Sized)) -> Self {
+37        let number_space_0 = PacketNumberSpace::new(now, space, rng);
+38        Self {
+39            pending: Retransmits::default(),
+40            number_spaces: BTreeMap::from([(PathId::ZERO, number_space_0)]),
+41        }
+42    }
+43
+44    #[cfg(test)]
+45    pub(super) fn new_deterministic(now: Instant, space: SpaceId) -> Self {
+46        let number_space_0 = PacketNumberSpace::new_deterministic(now, space);
+47        Self {
+48            pending: Retransmits::default(),
+49            number_spaces: BTreeMap::from([(PathId::ZERO, number_space_0)]),
+50        }
+51    }
+52
+53    /// Returns the [`PacketNumberSpace`] for a path
+54    ///
+55    /// When multipath is disabled use [`PathId::ZERO`].
+56    pub(super) fn path_space(&self, path_id: PathId) -> Option<&PacketNumberSpace> {
+57        self.number_spaces.get(&path_id)
+58    }
+59
+60    /// Returns a mutable reference to the [`PacketNumberSpace`] for a path
+61    ///
+62    /// When multipath is disabled use [`PathId::ZERO`].
+63    pub(super) fn path_space_mut(&mut self, path_id: PathId) -> Option<&mut PacketNumberSpace> {
+64        self.number_spaces.get_mut(&path_id)
+65    }
+66
+67    /// Returns the [`PacketNumberSpace`] for a path
+68    ///
+69    /// When multipath is disabled use `PathId::ZERO`.
+70    // TODO(flub): Note that this only exists as `&mut self` because it creates a new
+71    //    [`PacketNumberSpace`] if one is not yet available for a path.  This forces a few
+72    //    more `&mut` references to users than strictly needed.  An alternative would be to
+73    //    return an Option but that would need to be handled for all callers.  This could be
+74    //    worth exploring once we have all the main multipath bits fitted.
+75    pub(super) fn for_path(&mut self, path: PathId) -> &mut PacketNumberSpace {
+76        self.number_spaces
+77            .get_mut(&path)
+78            .unwrap_or_else(|| panic!("PacketNumberSpace missing for {path}"))
+79    }
+80
+81    pub(super) fn iter_paths_mut(&mut self) -> impl Iterator<Item = &mut PacketNumberSpace> {
+82        self.number_spaces.values_mut()
+83    }
+84
+85    /// Queue data for a tail loss probe (or anti-amplification deadlock prevention) packet
+86    ///
+87    /// Probes are sent similarly to normal packets when an expected ACK has not arrived. We never
+88    /// deem a packet lost until we receive an ACK that should have included it, but if a trailing
+89    /// run of packets (or their ACKs) are lost, this might not happen in a timely fashion. We send
+90    /// probe packets to force an ACK, and exempt them from congestion control to prevent a deadlock
+91    /// when the congestion window is filled with lost tail packets.
+92    ///
+93    /// We prefer to send new data, to make the most efficient use of bandwidth. If there's no data
+94    /// waiting to be sent, then we retransmit in-flight data to reduce odds of loss. If there's no
+95    /// in-flight data either, we're probably a client guarding against a handshake
+96    /// anti-amplification deadlock and we just make something up.
+97    pub(super) fn queue_tail_loss_probe(
+98        &mut self,
+99        path_id: PathId,
+100        request_immediate_ack: bool,
+101        streams: &StreamsState,
+102    ) {
+103        if request_immediate_ack {
+104            // The probe should be ACKed without delay (should only be used in the Data space and
+105            // when the peer supports the acknowledgement frequency extension)
+106            self.for_path(path_id).immediate_ack_pending = true;
+107        }
+108
+109        // We prefer to send new data to make most efficient use of bandwidth.
+110        if !self.pending.is_empty(streams) {
+111            // There's real data to send here, no need to make something up
+112            return;
+113        }
+114
+115        // Retransmit data from the oldest in-flight data from any path
+116        for packet in self
+117            .number_spaces
+118            .values_mut()
+119            .flat_map(|s| s.sent_packets.values_mut())
+120        {
+121            if !packet.retransmits.is_empty(streams) {
+122                // Remove retransmitted data from the old packet so we don't end up retransmitting
+123                // it *again* even if the copy we're sending now gets acknowledged.
+124                self.pending |= mem::take(&mut packet.retransmits);
+125                return;
+126            }
+127        }
+128
+129        // Nothing new to send and nothing to retransmit, so fall back on a ping. This should only
+130        // happen in rare cases during the handshake when the server becomes blocked by
+131        // anti-amplification.
+132        if !self.for_path(path_id).immediate_ack_pending {
+133            self.for_path(path_id).ping_pending = true;
+134        }
+135    }
+136
+137    /// Whether there is anything to send in this space
+138    ///
+139    /// For the data space [`Connection::can_send_1rtt`] also needs to be consulted. Prefer
+140    /// to use [`Connection::space_can_send`] which handles this.
+141    ///
+142    /// [`Connection::can_send_1rtt`]: super::Connection::can_send_1rtt
+143    /// [`Connection::space_can_send`]: super::Connection::space_can_send
+144    pub(super) fn can_send(&self, path_id: PathId, streams: &StreamsState) -> SendableFrames {
+145        let acks = self
+146            .number_spaces
+147            .values()
+148            .any(|pns| pns.pending_acks.can_send());
+149        let space_specific = self
+150            .number_spaces
+151            .get(&path_id)
+152            .is_some_and(|s| s.ping_pending || s.immediate_ack_pending);
+153        let other = !self.pending.is_empty(streams);
+154        SendableFrames {
+155            acks,
+156            close: false,
+157            space_specific,
+158            other,
+159        }
+160    }
+161}
+162
+163impl Index<SpaceId> for [PacketSpace; 3] {
+164    type Output = PacketSpace;
+165    fn index(&self, space: SpaceId) -> &PacketSpace {
+166        &self.as_ref()[space as usize]
+167    }
+168}
+169
+170impl IndexMut<SpaceId> for [PacketSpace; 3] {
+171    fn index_mut(&mut self, space: SpaceId) -> &mut PacketSpace {
+172        &mut self.as_mut()[space as usize]
+173    }
+174}
+175
+176/// The three QUIC packet number space kinds
+177///
+178/// Unlike [`SpaceId`], this always has exactly three variants — it represents the
+179/// encryption level / space kind, not a specific packet number space identity.
+180#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+181pub(crate) enum SpaceKind {
+182    /// Initial packets (client and server).
+183    Initial = 0,
+184    /// Handshake packets.
+185    Handshake = 1,
+186    /// Data (1-RTT and 0-RTT)
+187    Data = 2,
+188}
+189
+190impl SpaceKind {
+191    /// Returns the encryption level for this space kind.
+192    pub(crate) fn encryption_level(self) -> super::EncryptionLevel {
+193        match self {
+194            Self::Initial => super::EncryptionLevel::Initial,
+195            Self::Handshake => super::EncryptionLevel::Handshake,
+196            Self::Data => super::EncryptionLevel::OneRtt,
+197        }
+198    }
+199}
+200
+201impl Index<SpaceKind> for [PacketSpace; 3] {
+202    type Output = PacketSpace;
+203    fn index(&self, space: SpaceKind) -> &PacketSpace {
+204        &self.as_ref()[space as usize]
+205    }
+206}
+207
+208impl IndexMut<SpaceKind> for [PacketSpace; 3] {
+209    fn index_mut(&mut self, space: SpaceKind) -> &mut PacketSpace {
+210        &mut self.as_mut()[space as usize]
+211    }
+212}
+213
+214/// The state of a single packet number space.
+215///
+216/// In RFC9000 there are 3 packet number spaces: Initial, Handshake and Data. In QUIC
+217/// Multipath there are multiple packet number spaces for Data, each identified by a
+218/// [`PathId`].
+219///
+220/// This contains the state for a packet number space which is not specific to the 4-tuple
+221/// this space is currently using. The 4-tuple specific state, like congestion controller,
+222/// pacing, ECN, MTU etc, is stored in [`PathData`].
+223///
+224/// Note that the `Initial`, `Handshake` and `Data(PathId(0))` space all share the same
+225/// [`PathData`].
+226///
+227/// You should access this via [`PacketSpace::for_path`].
+228///
+229/// [`PathData`]: super::paths::PathData
+230pub(super) struct PacketNumberSpace {
+231    /// Highest received packet number, if any
+232    pub(super) largest_received_packet_number: Option<u64>,
+233    /// The packet number of the next packet that will be sent, if any. In the Data space, the
+234    /// packet number stored here is sometimes skipped by [`PacketNumberFilter`] logic.
+235    pub(super) next_packet_number: u64,
+236    /// The largest packet number the remote peer acknowledged in an ACK frame.
+237    pub(super) largest_acked_packet_pn: Option<u64>,
+238    pub(super) largest_acked_packet_send_time: Instant,
+239    /// The highest-numbered ACK-eliciting packet we've sent
+240    pub(super) largest_ack_eliciting_sent: u64,
+241    /// Number of packets in `sent_packets` with numbers above `largest_ack_eliciting_sent`
+242    pub(super) unacked_non_ack_eliciting_tail: u64,
+243    /// Transmitted but not acked
+244    // We use a BTreeMap here so we can efficiently query by range on ACK and for loss detection
+245    pub(super) sent_packets: SortedIndexBuffer<SentPacket>,
+246    /// Packets that were deemed lost
+247    // Older packets are regularly removed in `Connection::drain_lost_packets`.
+248    pub(super) lost_packets: SortedIndexBuffer<LostPacket>,
+249    /// Number of explicit congestion notification codepoints seen on incoming packets
+250    pub(super) ecn_counters: frame::EcnCounts,
+251    /// Recent ECN counters sent by the peer in ACK frames
+252    ///
+253    /// Updated (and inspected) whenever we receive an ACK with a new highest acked packet
+254    /// number. Stored per-space to simplify verification, which would otherwise have difficulty
+255    /// distinguishing between ECN bleaching and counts having been updated by a near-simultaneous
+256    /// ACK already processed in another space.
+257    pub(super) ecn_feedback: frame::EcnCounts,
+258    /// A PING frame needs to be sent on this path
+259    pub(super) ping_pending: bool,
+260    /// An IMMEDIATE_ACK (draft-ietf-quic-ack-frequency) frame needs to be sent on this path
+261    pub(super) immediate_ack_pending: bool,
+262    /// Packet deduplicator
+263    pub(super) dedup: Dedup,
+264    /// Packet numbers to acknowledge
+265    pub(super) pending_acks: PendingAcks,
+266
+267    //
+268    // Loss Detection
+269    //
+270    /// The time the most recently sent retransmittable packet was sent.
+271    pub(super) time_of_last_ack_eliciting_packet: Option<Instant>,
+272    /// Earliest time when we might declare a packet lost.
+273    ///
+274    /// The time at which the earliest sent packet in this space will be considered lost
+275    /// based on exceeding the reordering window in time. Only set for packets numbered
+276    /// prior to a packet that has been acknowledged.
+277    pub(super) loss_time: Option<Instant>,
+278    /// Number of tail loss probes to send
+279    pub(super) loss_probes: u32,
+280
+281    /// Packet numbers to skip, only used in the data package space.
+282    pn_filter: Option<PacketNumberFilter>,
+283}
+284
+285impl PacketNumberSpace {
+286    pub(super) fn new(now: Instant, space: SpaceId, rng: &mut (impl CryptoRng + ?Sized)) -> Self {
+287        let pn_filter = match space {
+288            SpaceId::Initial | SpaceId::Handshake => None,
+289            SpaceId::Data => Some(PacketNumberFilter::new(rng)),
+290        };
+291        Self {
+292            largest_received_packet_number: None,
+293            next_packet_number: 0,
+294            largest_acked_packet_pn: None,
+295            largest_acked_packet_send_time: now,
+296            largest_ack_eliciting_sent: 0,
+297            unacked_non_ack_eliciting_tail: 0,
+298            sent_packets: SortedIndexBuffer::new(),
+299            lost_packets: SortedIndexBuffer::new(),
+300            ecn_counters: frame::EcnCounts::ZERO,
+301            ecn_feedback: frame::EcnCounts::ZERO,
+302            ping_pending: false,
+303            immediate_ack_pending: false,
+304            dedup: Default::default(),
+305            pending_acks: PendingAcks::new(),
+306            time_of_last_ack_eliciting_packet: None,
+307            loss_time: None,
+308            loss_probes: 0,
+309            pn_filter,
+310        }
+311    }
+312
+313    #[cfg(test)]
+314    fn new_deterministic(now: Instant, space: SpaceId) -> Self {
+315        let pn_filter = match space {
+316            SpaceId::Initial | SpaceId::Handshake => None,
+317            SpaceId::Data => Some(PacketNumberFilter::disabled()),
+318        };
+319        Self {
+320            largest_received_packet_number: None,
+321            next_packet_number: 0,
+322            largest_acked_packet_pn: None,
+323            largest_acked_packet_send_time: now,
+324            largest_ack_eliciting_sent: 0,
+325            unacked_non_ack_eliciting_tail: 0,
+326            sent_packets: SortedIndexBuffer::new(),
+327            lost_packets: SortedIndexBuffer::new(),
+328            ecn_counters: frame::EcnCounts::ZERO,
+329            ecn_feedback: frame::EcnCounts::ZERO,
+330            ping_pending: false,
+331            immediate_ack_pending: false,
+332            dedup: Default::default(),
+333            pending_acks: PendingAcks::new(),
+334            time_of_last_ack_eliciting_packet: None,
+335            loss_time: None,
+336            loss_probes: 0,
+337            pn_filter,
+338        }
+339    }
+340
+341    /// Get the next outgoing packet number in this space
+342    ///
+343    /// In the Data space, the connection's [`PacketNumberFilter`] must be used rather than calling
+344    /// this directly.
+345    pub(super) fn get_tx_number(&mut self, rng: &mut (impl CryptoRng + ?Sized)) -> u64 {
+346        // TODO: Handle packet number overflow gracefully
+347        assert!(self.next_packet_number < 2u64.pow(62));
+348        let mut pn = self.next_packet_number;
+349        self.next_packet_number += 1;
+350
+351        // Skip this number if the filter says so, only enabled in the data space
+352        if let Some(ref mut filter) = self.pn_filter
+353            && filter.skip_pn(pn, rng)
+354        {
+355            pn = self.next_packet_number;
+356            self.next_packet_number += 1;
+357        }
+358        pn
+359    }
+360
+361    pub(super) fn peek_tx_number(&mut self) -> u64 {
+362        let pn = self.next_packet_number;
+363        if let Some(ref filter) = self.pn_filter
+364            && pn == filter.next_skipped_packet_number
+365        {
+366            return pn + 1;
+367        }
+368        pn
+369    }
+370
+371    /// Checks whether a skipped packet number was ACKed.
+372    pub(super) fn check_ack(&self, range: std::ops::Range<u64>) -> Result<(), TransportError> {
+373        if let Some(ref filter) = self.pn_filter
+374            && filter
+375                .prev_skipped_packet_number
+376                .is_some_and(|pn| range.contains(&pn))
+377        {
+378            return Err(TransportError::PROTOCOL_VIOLATION("unsent packet acked"));
+379        }
+380        Ok(())
+381    }
+382
+383    /// Verifies sanity of an ECN block and returns whether congestion was encountered.
+384    pub(super) fn detect_ecn(
+385        &mut self,
+386        newly_acked: u64,
+387        ecn: frame::EcnCounts,
+388    ) -> Result<bool, &'static str> {
+389        let ect0_increase = ecn
+390            .ect0
+391            .checked_sub(self.ecn_feedback.ect0)
+392            .ok_or("peer ECT(0) count regression")?;
+393        let ect1_increase = ecn
+394            .ect1
+395            .checked_sub(self.ecn_feedback.ect1)
+396            .ok_or("peer ECT(1) count regression")?;
+397        let ce_increase = ecn
+398            .ce
+399            .checked_sub(self.ecn_feedback.ce)
+400            .ok_or("peer CE count regression")?;
+401        let total_increase = ect0_increase + ect1_increase + ce_increase;
+402        if total_increase < newly_acked {
+403            return Err("ECN bleaching");
+404        }
+405        if (ect0_increase + ce_increase) < newly_acked || ect1_increase != 0 {
+406            return Err("ECN corruption");
+407        }
+408        // If total_increase > newly_acked (which happens when ACKs are lost), this is required by
+409        // the draft so that long-term drift does not occur. If =, then the only question is whether
+410        // to count CE packets as CE or ECT0. Recording them as CE is more consistent and keeps the
+411        // congestion check obvious.
+412        self.ecn_feedback = ecn;
+413        Ok(ce_increase != 0)
+414    }
+415
+416    /// Stop tracking sent packet `number`, and return what we knew about it
+417    pub(super) fn take(&mut self, number: u64) -> Option<SentPacket> {
+418        let packet = self.sent_packets.remove(number)?;
+419        if !packet.ack_eliciting && number > self.largest_ack_eliciting_sent {
+420            self.unacked_non_ack_eliciting_tail =
+421                self.unacked_non_ack_eliciting_tail.checked_sub(1).unwrap();
+422        }
+423        Some(packet)
+424    }
+425
+426    /// May return a packet that should be forgotten
+427    pub(super) fn sent(&mut self, number: u64, packet: SentPacket) -> Option<SentPacket> {
+428        // Retain state for at most this many non-ACK-eliciting packets sent after the most recently
+429        // sent ACK-eliciting packet. We're never guaranteed to receive an ACK for those, and we
+430        // can't judge them as lost without an ACK, so to limit memory in applications which receive
+431        // packets but don't send ACK-eliciting data for long periods use we must eventually start
+432        // forgetting about them, although it might also be reasonable to just kill the connection
+433        // due to weird peer behavior.
+434        const MAX_UNACKED_NON_ACK_ELICTING_TAIL: u64 = 1_000;
+435
+436        let mut forgotten = None;
+437        if packet.ack_eliciting {
+438            self.unacked_non_ack_eliciting_tail = 0;
+439            self.largest_ack_eliciting_sent = number;
+440        } else if self.unacked_non_ack_eliciting_tail > MAX_UNACKED_NON_ACK_ELICTING_TAIL {
+441            let oldest_after_ack_eliciting = self
+442                .sent_packets
+443                .keys_range((
+444                    Bound::Excluded(self.largest_ack_eliciting_sent),
+445                    Bound::Unbounded,
+446                ))
+447                .next()
+448                .unwrap();
+449            // Per https://www.rfc-editor.org/rfc/rfc9000.html#name-frames-and-frame-types,
+450            // non-ACK-eliciting packets must only contain PADDING, ACK, and CONNECTION_CLOSE
+451            // frames, which require no special handling on ACK or loss beyond removal from
+452            // in-flight counters if padded.
+453            let packet = self
+454                .sent_packets
+455                .remove(oldest_after_ack_eliciting)
+456                .unwrap();
+457            debug_assert!(!packet.ack_eliciting);
+458            forgotten = Some(packet);
+459        } else {
+460            self.unacked_non_ack_eliciting_tail += 1;
+461        }
+462
+463        self.sent_packets.insert(number, packet);
+464        forgotten
+465    }
+466
+467    /// Whether any congestion-controlled packets in this space are not yet acknowledged or lost
+468    pub(super) fn has_in_flight(&self) -> bool {
+469        // The number of non-congestion-controlled (i.e. size == 0) packets in flight at a time
+470        // should be small, since otherwise congestion control wouldn't be effective. Therefore,
+471        // this shouldn't need to visit many packets before finishing one way or another.
+472        self.sent_packets.values().any(|x| x.size != 0)
+473    }
+474}
+475
+476/// Represents one or more packets subject to retransmission
+477#[derive(Debug, Clone)]
+478pub(super) struct SentPacket {
+479    /// [`PathData::generation`](super::PathData::generation) of the path on which this packet was sent
+480    pub(super) path_generation: u64,
+481    /// The time the packet was sent.
+482    pub(super) time_sent: Instant,
+483    /// The number of bytes sent in the packet, not including UDP or IP overhead, but including QUIC
+484    /// framing overhead. Zero if this packet is not counted towards congestion control, i.e. not an
+485    /// "in flight" packet.
+486    pub(super) size: u16,
+487    /// Whether an acknowledgement is expected directly in response to this packet.
+488    pub(super) ack_eliciting: bool,
+489    /// The largest packet number acknowledged by this packet
+490    pub(super) largest_acked: FxHashMap<PathId, u64>,
+491    /// Data which needs to be retransmitted in case the packet is lost.
+492    /// The data is boxed to minimize `SentPacket` size for the typical case of
+493    /// packets only containing ACKs and STREAM frames.
+494    pub(super) retransmits: ThinRetransmits,
+495    /// Metadata for stream frames in a packet
+496    ///
+497    /// The actual application data is stored with the stream state.
+498    pub(super) stream_frames: frame::StreamMetaVec,
+499}
+500
+501/// Represents one or more packets that are deemed lost.
+502#[derive(Debug)]
+503pub(super) struct LostPacket {
+504    /// The time the packet was sent.
+505    pub(super) time_sent: Instant,
+506}
+507
+508/// Retransmittable data queue
+509#[allow(unreachable_pub)] // fuzzing only
+510#[derive(Debug, Default, Clone)]
+511pub struct Retransmits {
+512    pub(super) max_data: bool,
+513    pub(super) max_stream_id: [bool; 2],
+514    pub(super) streams_blocked: [bool; 2],
+515    pub(super) reset_stream: Vec<(StreamId, VarInt)>,
+516    pub(super) stop_sending: Vec<frame::StopSending>,
+517    pub(super) max_stream_data: FxHashSet<StreamId>,
+518    pub(super) crypto: VecDeque<frame::Crypto>,
+519    pub(super) new_cids: PendingNewCids,
+520    pub(super) retire_cids: Vec<(PathId, u64)>,
+521    pub(super) ack_frequency: bool,
+522    pub(super) handshake_done: bool,
+523    pub(super) observed_addr: bool,
+524    /// Whether we should inform the peer we will allow higher [`PathId`]s.
+525    pub(super) max_path_id: bool,
+526    /// Whether we should inform the peer that their max [`PathId`] is blocking our attempt to open
+527    /// new paths.
+528    // TODO(@divma): we need logic to prevent sending this more than once after being ack-d once
+529    pub(super) paths_blocked: bool,
+530    /// For each enqueued NEW_TOKEN frame, a copy of the path's remote address
+531    ///
+532    /// There are 2 reasons this is unusual:
+533    ///
+534    /// - If the path changes, NEW_TOKEN frames bound for the old path are not retransmitted on the
+535    ///   new path. That is why this field stores the remote address: so that ones for old paths
+536    ///   can be filtered out.
+537    /// - If a token is lost, a new randomly generated token is re-transmitted, rather than the
+538    ///   original. This is so that if both transmissions are received, the client won't risk
+539    ///   sending the same token twice. That is why this field does _not_ store any actual token.
+540    ///
+541    /// It is true that a QUIC endpoint will only want to effectively have NEW_TOKEN frames
+542    /// enqueued for its current path at a given point in time. Based on that, we could conceivably
+543    /// change this from a vector to an `Option<(FourTuple, usize)>` or just a `usize` or
+544    /// something. However, due to the architecture of noq, it is considerably simpler to not do
+545    /// that; consider what such a change would mean for implementing `BitOrAssign` on Self.
+546    pub(super) new_tokens: Vec<FourTuple>,
+547    /// Paths which need to be abandoned
+548    pub(super) path_abandon: BTreeMap<PathId, TransportErrorCode>,
+549    /// If a [`frame::PathStatusAvailable`] and [`frame::PathStatusBackup`] need to be sent for a path
+550    pub(super) path_status: BTreeSet<PathId>,
+551    /// If a PATH_CIDS_BLOCKED frame needs to be sent for a path
+552    pub(super) path_cids_blocked: BTreeSet<PathId>,
+553
+554    // Nat traversal data
+555    /// Addresses to report in `ADD_ADDRESS` frames
+556    pub(super) add_address: BTreeSet<AddAddress>,
+557    /// Address IDs to remove in `REMOVE_ADDRESS` frames
+558    pub(super) remove_address: BTreeSet<RemoveAddress>,
+559    /// Round and local addresses to advertise in `REACH_OUT` frames
+560    pub(super) reach_out: PendingReachOutFrames,
+561}
+562
+563impl Retransmits {
+564    pub(super) fn is_empty(&self, streams: &StreamsState) -> bool {
+565        let Self {
+566            max_data,
+567            max_stream_id,
+568            streams_blocked,
+569            reset_stream,
+570            stop_sending,
+571            max_stream_data,
+572            crypto,
+573            new_cids,
+574            retire_cids,
+575            ack_frequency,
+576            handshake_done,
+577            observed_addr,
+578            max_path_id,
+579            paths_blocked,
+580            new_tokens,
+581            path_abandon,
+582            path_status,
+583            path_cids_blocked,
+584            add_address,
+585            remove_address,
+586            reach_out,
+587        } = &self;
+588        !max_data
+589            && !max_stream_id.iter().any(|x| *x)
+590            && !streams_blocked.iter().any(|x| *x)
+591            && reset_stream.is_empty()
+592            && stop_sending.is_empty()
+593            && max_stream_data
+594                .iter()
+595                .all(|&id| !streams.can_send_flow_control(id))
+596            && crypto.is_empty()
+597            && new_cids.is_empty()
+598            && retire_cids.is_empty()
+599            && !ack_frequency
+600            && !handshake_done
+601            && !observed_addr
+602            && !max_path_id
+603            && !paths_blocked
+604            && new_tokens.is_empty()
+605            && path_abandon.is_empty()
+606            && path_status.is_empty()
+607            && path_cids_blocked.is_empty()
+608            && add_address.is_empty()
+609            && remove_address.is_empty()
+610            && reach_out.is_empty()
+611    }
+612}
+613
+614impl ::std::ops::BitOrAssign for Retransmits {
+615    fn bitor_assign(&mut self, rhs: Self) {
+616        let Self {
+617            max_data,
+618            max_stream_id,
+619            streams_blocked,
+620            reset_stream,
+621            stop_sending,
+622            max_stream_data,
+623            crypto,
+624            new_cids,
+625            retire_cids,
+626            ack_frequency,
+627            handshake_done,
+628            observed_addr,
+629            max_path_id,
+630            paths_blocked,
+631            new_tokens,
+632            mut path_abandon,
+633            mut path_status,
+634            mut path_cids_blocked,
+635            add_address,
+636            remove_address,
+637            mut reach_out,
+638        } = rhs;
+639
+640        // We reduce in-stream head-of-line blocking by queueing retransmits before other data for
+641        // STREAM and CRYPTO frames.
+642        self.max_data |= max_data;
+643        for dir in Dir::iter() {
+644            self.max_stream_id[dir as usize] |= max_stream_id[dir as usize];
+645            self.streams_blocked[dir as usize] |= streams_blocked[dir as usize];
+646        }
+647        self.reset_stream.extend_from_slice(&reset_stream);
+648        self.stop_sending.extend_from_slice(&stop_sending);
+649        self.max_stream_data.extend(&max_stream_data);
+650        for crypto in crypto.into_iter().rev() {
+651            self.crypto.push_front(crypto);
+652        }
+653        self.new_cids.extend(&new_cids);
+654        self.retire_cids.extend(retire_cids);
+655        self.ack_frequency |= ack_frequency;
+656        self.handshake_done |= handshake_done;
+657        self.observed_addr |= observed_addr;
+658        self.max_path_id |= max_path_id;
+659        self.paths_blocked |= paths_blocked;
+660        self.new_tokens.extend_from_slice(&new_tokens);
+661        self.path_abandon.append(&mut path_abandon);
+662        self.path_status.append(&mut path_status);
+663        self.path_cids_blocked.append(&mut path_cids_blocked);
+664        self.add_address.extend(add_address.iter().copied());
+665        self.remove_address.extend(remove_address.iter().copied());
+666        self.reach_out.append(&mut reach_out);
+667    }
+668}
+669
+670impl ::std::ops::BitOrAssign<ThinRetransmits> for Retransmits {
+671    fn bitor_assign(&mut self, rhs: ThinRetransmits) {
+672        let ThinRetransmits { retransmits } = rhs;
+673        if let Some(retransmits) = retransmits {
+674            self.bitor_assign(*retransmits)
+675        }
+676    }
+677}
+678
+679impl ::std::iter::FromIterator<Self> for Retransmits {
+680    fn from_iter<T>(iter: T) -> Self
+681    where
+682        T: IntoIterator<Item = Self>,
+683    {
+684        let mut result = Self::default();
+685        for packet in iter {
+686            result |= packet;
+687        }
+688        result
+689    }
+690}
+691
+692/// The queue of new CIDs to be transmitted to the peer.
+693///
+694/// This queue is always sorted, so that popping off the last item is always the lowest
+695/// sequence number of the lowest path ID. Which is the CID you want to be issued next.
+696///
+697/// This is but a newtype over a `Vec` to enforce the sorted invariant.
+698#[derive(Clone, Debug, Default)]
+699pub(super) struct PendingNewCids {
+700    /// The CIDs themselves.
+701    cids: Vec<IssuedCid>,
+702    /// Whether [`Self::cids`] is sorted or not.
+703    sorted: bool,
+704}
+705
+706impl PendingNewCids {
+707    /// Inserts an issued CID into the queue.
+708    pub(super) fn push(&mut self, cid: IssuedCid) {
+709        self.cids.push(cid);
+710        self.sorted = false;
+711    }
+712
+713    /// Pops the next issued CID to transmit from the queue.
+714    pub(super) fn pop(&mut self) -> Option<IssuedCid> {
+715        if !std::mem::replace(&mut self.sorted, true) {
+716            self.cids
+717                .sort_by_key(|cid| cmp::Reverse((cid.path_id, cid.sequence)));
+718        }
+719        self.cids.pop()
+720    }
 721
-722impl PendingNewCids {
-723    /// Inserts an issued CID into the queue.
-724    pub(super) fn push(&mut self, cid: IssuedCid) {
-725        self.cids.push(cid);
-726        self.sorted = false;
-727    }
-728
-729    /// Pops the next issued CID to transmit from the queue.
-730    pub(super) fn pop(&mut self) -> Option<IssuedCid> {
-731        if !std::mem::replace(&mut self.sorted, true) {
-732            self.cids
-733                .sort_by_key(|cid| cmp::Reverse((cid.path_id, cid.sequence)));
-734        }
-735        self.cids.pop()
+722    pub(super) fn is_empty(&self) -> bool {
+723        self.cids.is_empty()
+724    }
+725
+726    pub(super) fn extend(&mut self, other: &Self) {
+727        self.cids.extend(&other.cids);
+728        self.sorted = false;
+729    }
+730
+731    pub(super) fn retain<F>(&mut self, f: F)
+732    where
+733        F: FnMut(&IssuedCid) -> bool,
+734    {
+735        self.cids.retain(f);
 736    }
-737
-738    pub(super) fn is_empty(&self) -> bool {
-739        self.cids.is_empty()
-740    }
-741
-742    pub(super) fn extend(&mut self, other: &Self) {
-743        self.cids.extend(&other.cids);
-744        self.sorted = false;
-745    }
-746
-747    pub(super) fn retain<F>(&mut self, f: F)
-748    where
-749        F: FnMut(&IssuedCid) -> bool,
-750    {
-751        self.cids.retain(f);
-752    }
-753}
-754
-755/// A variant of `Retransmits` which only allocates storage when required
-756#[derive(Debug, Default, Clone)]
-757pub(super) struct ThinRetransmits {
-758    retransmits: Option<Box<Retransmits>>,
-759}
-760
-761impl ThinRetransmits {
-762    /// Returns `true` if no retransmits are necessary
-763    pub(super) fn is_empty(&self, streams: &StreamsState) -> bool {
-764        match &self.retransmits {
-765            Some(retransmits) => retransmits.is_empty(streams),
-766            None => true,
-767        }
-768    }
-769
-770    /// Returns a reference to the retransmits stored in this box
-771    pub(super) fn get(&self) -> Option<&Retransmits> {
-772        self.retransmits.as_deref()
-773    }
-774
-775    /// Returns a mutable reference to the retransmits stored in this box
-776    pub(super) fn get_mut(&mut self) -> Option<&mut Retransmits> {
-777        self.retransmits.as_deref_mut()
-778    }
-779
-780    /// Returns a mutable reference to the stored retransmits
-781    ///
-782    /// This function will allocate a backing storage if required.
-783    pub(super) fn get_or_create(&mut self) -> &mut Retransmits {
-784        if self.retransmits.is_none() {
-785            self.retransmits = Some(Box::default());
-786        }
-787        self.retransmits.as_deref_mut().unwrap()
+737}
+738
+739/// Logically a Vec of REACH_OUT frames queued for transmit.
+740///
+741/// This keeps track of the highest round ID and automatically drops frames with a lower
+742/// round ID.
+743///
+744/// The API is directly modelled on [`Vec`].
+745#[derive(Debug, Default, Clone)]
+746pub(crate) struct PendingReachOutFrames {
+747    /// The round ID of the REACH_OUT frames currently pending.
+748    round: VarInt,
+749    /// The REACH_OUT frames, always all having the same round ID.
+750    frames: Vec<frame::ReachOut>,
+751}
+752
+753impl PendingReachOutFrames {
+754    pub(crate) fn len(&self) -> usize {
+755        self.frames.len()
+756    }
+757
+758    pub(crate) fn is_empty(&self) -> bool {
+759        self.frames.is_empty()
+760    }
+761
+762    pub(crate) fn push(&mut self, frame: frame::ReachOut) {
+763        if frame.round < self.round {
+764            return;
+765        } else if frame.round > self.round {
+766            self.round = frame.round;
+767            self.frames.clear();
+768        }
+769        self.frames.push(frame);
+770    }
+771
+772    pub(crate) fn append(&mut self, other: &mut Self) {
+773        if other.round < self.round {
+774            other.frames.clear();
+775            return;
+776        } else if other.round > self.round {
+777            self.round = other.round;
+778            self.frames.clear();
+779        }
+780        self.frames.append(&mut other.frames);
+781    }
+782
+783    pub(crate) fn pop_if(
+784        &mut self,
+785        predicate: impl FnOnce(&mut frame::ReachOut) -> bool,
+786    ) -> Option<frame::ReachOut> {
+787        self.frames.pop_if(predicate)
 788    }
 789}
 790
-791/// RFC4303-style sliding window packet number deduplicator.
-792///
-793/// A contiguous bitfield, where each bit corresponds to a packet number and the rightmost bit is
-794/// always set. A set bit represents a packet that has been successfully authenticated. Bits left of
-795/// the window are assumed to be set.
-796///
-797/// ```text
-798/// ...xxxxxxxxx 1 0
-799///     ^        ^ ^
-800/// window highest next
-801/// ```
-802#[derive(Debug, Default)]
-803pub(super) struct Dedup {
-804    window: Window,
-805    /// Lowest packet number higher than all yet authenticated.
-806    next: u64,
-807}
-808
-809/// Inner bitfield type.
-810///
-811/// Because QUIC never reuses packet numbers, this only needs to be large enough to deal with
-812/// packets that are reordered but still delivered in a timely manner.
-813type Window = u128;
-814
-815/// Number of packets tracked by `Dedup`.
-816const WINDOW_SIZE: u64 = 1 + mem::size_of::<Window>() as u64 * 8;
-817
-818impl Dedup {
-819    /// Construct an empty window positioned at the start.
-820    #[cfg(test)]
-821    pub(super) fn new() -> Self {
-822        Self { window: 0, next: 0 }
-823    }
-824
-825    /// Highest packet number authenticated.
-826    fn highest(&self) -> u64 {
-827        self.next - 1
-828    }
-829
-830    /// Record a newly authenticated packet number.
-831    ///
-832    /// Returns whether the packet might be a duplicate.
-833    pub(super) fn insert(&mut self, packet: u64) -> bool {
-834        if let Some(diff) = packet.checked_sub(self.next) {
-835            // Right of window
-836            self.window = ((self.window << 1) | 1)
-837                .checked_shl(cmp::min(diff, u64::from(u32::MAX)) as u32)
-838                .unwrap_or(0);
-839            self.next = packet + 1;
-840            false
-841        } else if self.highest() - packet < WINDOW_SIZE {
-842            // Within window
-843            if let Some(bit) = (self.highest() - packet).checked_sub(1) {
-844                // < highest
-845                let mask = 1 << bit;
-846                let duplicate = self.window & mask != 0;
-847                self.window |= mask;
-848                duplicate
-849            } else {
-850                // == highest
-851                true
-852            }
-853        } else {
-854            // Left of window
-855            true
-856        }
-857    }
-858
-859    /// Returns the packet number of the smallest packet missing between the provided interval
-860    ///
-861    /// If there are no missing packets, returns `None`
-862    fn smallest_missing_in_interval(&self, lower_bound: u64, upper_bound: u64) -> Option<u64> {
-863        debug_assert!(lower_bound <= upper_bound);
-864        debug_assert!(upper_bound <= self.highest());
-865        const BITFIELD_SIZE: u64 = (mem::size_of::<Window>() * 8) as u64;
-866
-867        // Since we already know the packets at the boundaries have been received, we only need to
-868        // check those in between them (this removes the necessity of extra logic to deal with the
-869        // highest packet, which is stored outside the bitfield)
-870        let lower_bound = lower_bound + 1;
-871        let upper_bound = upper_bound.saturating_sub(1);
-872
-873        // Note: the offsets are counted from the right
-874        // The highest packet is not included in the bitfield, so we subtract 1 to account for that
-875        let start_offset = (self.highest() - upper_bound).max(1) - 1;
-876        if start_offset >= BITFIELD_SIZE {
-877            // The start offset is outside of the window. All packets outside of the window are
-878            // considered to be received.
-879            return None;
-880        }
-881
-882        let end_offset_exclusive = self.highest().saturating_sub(lower_bound);
-883
-884        // The range is clamped at the edge of the window, because any earlier packets are
-885        // considered to be received
-886        let range_len = end_offset_exclusive
-887            .saturating_sub(start_offset)
-888            .min(BITFIELD_SIZE);
-889        if range_len == 0 {
-890            return None;
-891        }
-892
-893        // Ensure the shift is within bounds (we already know start_offset < BITFIELD_SIZE,
-894        // because of the early return)
-895        let mask = if range_len == BITFIELD_SIZE {
-896            u128::MAX
-897        } else {
-898            ((1u128 << range_len) - 1) << start_offset
-899        };
-900        let gaps = !self.window & mask;
-901
-902        let smallest_missing_offset = 128 - gaps.leading_zeros() as u64;
-903        let smallest_missing_packet = self.highest() - smallest_missing_offset;
-904
-905        if smallest_missing_packet <= upper_bound {
-906            Some(smallest_missing_packet)
-907        } else {
-908            None
-909        }
-910    }
-911
-912    /// Returns true if there are any missing packets between the provided interval
-913    ///
-914    /// The provided packet numbers must have been received before calling this function
-915    fn missing_in_interval(&self, lower_bound: u64, upper_bound: u64) -> bool {
-916        self.smallest_missing_in_interval(lower_bound, upper_bound)
-917            .is_some()
-918    }
-919}
-920
-921/// Indicates which data is available for sending.
-922///
-923/// This applies to a particular space ID that was queried and all refers to on-path data.
-924#[derive(Clone, Copy, PartialEq, Eq, Debug)]
-925pub(super) struct SendableFrames {
-926    /// Whether there are ACK frames to send, these are not ack-eliciting.
-927    pub(super) acks: bool,
-928    /// Whether there is a CONNECTION_CLOSE to send, this is not ack-eliciting.
-929    pub(super) close: bool,
-930    /// Whether there are any frames that must be sent on this specific space.
-931    ///
-932    /// A space here in the sense of a QUIC Multipath packet number space: `Initial`,
-933    /// `Handshake` and all `Data(PathId)` spaces.
-934    ///
-935    /// These are ack-eliciting. Some frames are scheduled per path, e.g. PING,
-936    /// IMMEDIATE_ACK, PATH_CHALLENGE or PATH_RESPONSE.
-937    pub(super) space_specific: bool,
-938    /// Whether there are any other frames to send, these are ack-eliciting.
-939    pub(super) other: bool,
-940}
-941
-942impl SendableFrames {
-943    /// Returns that no data is available for sending
-944    pub(super) fn empty() -> Self {
-945        Self {
-946            acks: false,
-947            close: false,
-948            space_specific: false,
-949            other: false,
-950        }
-951    }
+791impl FromIterator<frame::ReachOut> for PendingReachOutFrames {
+792    fn from_iter<T: IntoIterator<Item = frame::ReachOut>>(iter: T) -> Self {
+793        let iter = iter.into_iter();
+794        let size_hint = iter.size_hint();
+795        let mut this = Self {
+796            round: Default::default(),
+797            frames: Vec::with_capacity(size_hint.1.unwrap_or(size_hint.0)),
+798        };
+799        for frame in iter {
+800            this.push(frame);
+801        }
+802        this
+803    }
+804}
+805
+806/// A variant of `Retransmits` which only allocates storage when required
+807#[derive(Debug, Default, Clone)]
+808pub(super) struct ThinRetransmits {
+809    retransmits: Option<Box<Retransmits>>,
+810}
+811
+812impl ThinRetransmits {
+813    /// Returns `true` if no retransmits are necessary
+814    pub(super) fn is_empty(&self, streams: &StreamsState) -> bool {
+815        match &self.retransmits {
+816            Some(retransmits) => retransmits.is_empty(streams),
+817            None => true,
+818        }
+819    }
+820
+821    /// Returns a reference to the retransmits stored in this box
+822    pub(super) fn get(&self) -> Option<&Retransmits> {
+823        self.retransmits.as_deref()
+824    }
+825
+826    /// Returns a mutable reference to the retransmits stored in this box
+827    pub(super) fn get_mut(&mut self) -> Option<&mut Retransmits> {
+828        self.retransmits.as_deref_mut()
+829    }
+830
+831    /// Returns a mutable reference to the stored retransmits
+832    ///
+833    /// This function will allocate a backing storage if required.
+834    pub(super) fn get_or_create(&mut self) -> &mut Retransmits {
+835        if self.retransmits.is_none() {
+836            self.retransmits = Some(Box::default());
+837        }
+838        self.retransmits.as_deref_mut().unwrap()
+839    }
+840}
+841
+842/// RFC4303-style sliding window packet number deduplicator.
+843///
+844/// A contiguous bitfield, where each bit corresponds to a packet number and the rightmost bit is
+845/// always set. A set bit represents a packet that has been successfully authenticated. Bits left of
+846/// the window are assumed to be set.
+847///
+848/// ```text
+849/// ...xxxxxxxxx 1 0
+850///     ^        ^ ^
+851/// window highest next
+852/// ```
+853#[derive(Debug, Default)]
+854pub(super) struct Dedup {
+855    window: Window,
+856    /// Lowest packet number higher than all yet authenticated.
+857    next: u64,
+858}
+859
+860/// Inner bitfield type.
+861///
+862/// Because QUIC never reuses packet numbers, this only needs to be large enough to deal with
+863/// packets that are reordered but still delivered in a timely manner.
+864type Window = u128;
+865
+866/// Number of packets tracked by `Dedup`.
+867const WINDOW_SIZE: u64 = 1 + mem::size_of::<Window>() as u64 * 8;
+868
+869impl Dedup {
+870    /// Construct an empty window positioned at the start.
+871    #[cfg(test)]
+872    pub(super) fn new() -> Self {
+873        Self { window: 0, next: 0 }
+874    }
+875
+876    /// Highest packet number authenticated.
+877    fn highest(&self) -> u64 {
+878        self.next - 1
+879    }
+880
+881    /// Record a newly authenticated packet number.
+882    ///
+883    /// Returns whether the packet might be a duplicate.
+884    pub(super) fn insert(&mut self, packet: u64) -> bool {
+885        if let Some(diff) = packet.checked_sub(self.next) {
+886            // Right of window
+887            self.window = ((self.window << 1) | 1)
+888                .checked_shl(cmp::min(diff, u64::from(u32::MAX)) as u32)
+889                .unwrap_or(0);
+890            self.next = packet + 1;
+891            false
+892        } else if self.highest() - packet < WINDOW_SIZE {
+893            // Within window
+894            if let Some(bit) = (self.highest() - packet).checked_sub(1) {
+895                // < highest
+896                let mask = 1 << bit;
+897                let duplicate = self.window & mask != 0;
+898                self.window |= mask;
+899                duplicate
+900            } else {
+901                // == highest
+902                true
+903            }
+904        } else {
+905            // Left of window
+906            true
+907        }
+908    }
+909
+910    /// Returns the packet number of the smallest packet missing between the provided interval
+911    ///
+912    /// If there are no missing packets, returns `None`
+913    fn smallest_missing_in_interval(&self, lower_bound: u64, upper_bound: u64) -> Option<u64> {
+914        debug_assert!(lower_bound <= upper_bound);
+915        debug_assert!(upper_bound <= self.highest());
+916        const BITFIELD_SIZE: u64 = (mem::size_of::<Window>() * 8) as u64;
+917
+918        // Since we already know the packets at the boundaries have been received, we only need to
+919        // check those in between them (this removes the necessity of extra logic to deal with the
+920        // highest packet, which is stored outside the bitfield)
+921        let lower_bound = lower_bound + 1;
+922        let upper_bound = upper_bound.saturating_sub(1);
+923
+924        // Note: the offsets are counted from the right
+925        // The highest packet is not included in the bitfield, so we subtract 1 to account for that
+926        let start_offset = (self.highest() - upper_bound).max(1) - 1;
+927        if start_offset >= BITFIELD_SIZE {
+928            // The start offset is outside of the window. All packets outside of the window are
+929            // considered to be received.
+930            return None;
+931        }
+932
+933        let end_offset_exclusive = self.highest().saturating_sub(lower_bound);
+934
+935        // The range is clamped at the edge of the window, because any earlier packets are
+936        // considered to be received
+937        let range_len = end_offset_exclusive
+938            .saturating_sub(start_offset)
+939            .min(BITFIELD_SIZE);
+940        if range_len == 0 {
+941            return None;
+942        }
+943
+944        // Ensure the shift is within bounds (we already know start_offset < BITFIELD_SIZE,
+945        // because of the early return)
+946        let mask = if range_len == BITFIELD_SIZE {
+947            u128::MAX
+948        } else {
+949            ((1u128 << range_len) - 1) << start_offset
+950        };
+951        let gaps = !self.window & mask;
 952
-953    /// Whether an ack-eliciting packet will be sent.
-954    pub(super) fn is_ack_eliciting(&self) -> bool {
-955        let Self {
-956            acks: _,
-957            close,
-958            space_specific,
-959            other,
-960        } = *self;
-961        if close {
-962            // No ack-eliciting frames are included with a CONNECTION_CLOSE, only acks.
-963            return false;
-964        }
-965        space_specific || other
-966    }
-967
-968    /// Whether no data is sendable.
-969    pub(super) fn is_empty(&self) -> bool {
-970        let Self {
-971            acks,
-972            close,
-973            space_specific,
-974            other,
-975        } = *self;
-976        !acks && !close && !space_specific && !other
-977    }
-978}
-979
-980impl ::std::ops::BitOrAssign for SendableFrames {
-981    fn bitor_assign(&mut self, rhs: Self) {
-982        let Self {
-983            acks,
-984            close,
-985            space_specific,
-986            other,
-987        } = rhs;
-988
-989        self.acks |= acks;
-990        self.close |= close;
-991        self.space_specific |= space_specific;
-992        self.other |= other;
-993    }
-994}
-995
-996#[derive(Debug)]
-997pub(super) struct PendingAcks {
-998    /// Whether we should send an ACK immediately, even if that means sending an ACK-only packet
-999    ///
-1000    /// When `immediate_ack_required` is false, the normal behavior is to send ACK frames only when
-1001    /// there is other data to send, or when the `MaxAckDelay` timer expires.
-1002    immediate_ack_required: bool,
-1003    /// The number of ack-eliciting packets received since the last ACK frame was sent
-1004    ///
-1005    /// Once the count _exceeds_ `ack_eliciting_threshold`, an immediate ACK is required
-1006    ack_eliciting_since_last_ack_sent: u64,
-1007    non_ack_eliciting_since_last_ack_sent: u64,
-1008    ack_eliciting_threshold: u64,
-1009    /// The reordering threshold, controlling how we respond to out-of-order ack-eliciting packets
-1010    ///
-1011    /// Different values enable different behavior:
-1012    ///
-1013    /// * `0`: no special action is taken
-1014    /// * `1`: an ACK is immediately sent if it is out-of-order according to RFC 9000
-1015    /// * `>1`: an ACK is immediately sent if it is out-of-order according to the ACK frequency draft
-1016    reordering_threshold: u64,
-1017    /// The earliest ack-eliciting packet since the last ACK was sent, used to calculate the moment
-1018    /// upon which `max_ack_delay` elapses
-1019    earliest_ack_eliciting_since_last_ack_sent: Option<Instant>,
-1020    /// Packet number ranges for which to still send acknowledgements.
-1021    ///
-1022    /// These are packet number ranges of ack-eliciting packets the peer has sent and which
-1023    /// need to be acknowledged.  Packet numbers are only removed from here once the peer has
-1024    /// acknowledged the ACKs for them.
-1025    ranges: ArrayRangeSet,
-1026    /// The largest packet number received and the time it was received
-1027    ///
-1028    /// Used to calculate ACK delay in [`PendingAcks::ack_delay`].
-1029    largest_packet: Option<(u64, Instant)>,
-1030    /// The ack-eliciting packet we have received with the largest packet number
-1031    largest_ack_eliciting_packet: Option<u64>,
-1032    /// The largest acknowledged packet number sent in an ACK frame
-1033    largest_acked: Option<u64>,
-1034}
-1035
-1036impl PendingAcks {
-1037    fn new() -> Self {
-1038        Self {
-1039            immediate_ack_required: false,
-1040            ack_eliciting_since_last_ack_sent: 0,
-1041            non_ack_eliciting_since_last_ack_sent: 0,
-1042            ack_eliciting_threshold: 1,
-1043            reordering_threshold: 1,
-1044            earliest_ack_eliciting_since_last_ack_sent: None,
-1045            ranges: Default::default(),
-1046            largest_packet: Default::default(),
-1047            largest_ack_eliciting_packet: Default::default(),
-1048            largest_acked: Default::default(),
-1049        }
-1050    }
-1051
-1052    pub(super) fn set_ack_frequency_params(&mut self, frame: &frame::AckFrequency) {
-1053        self.ack_eliciting_threshold = frame.ack_eliciting_threshold.into_inner();
-1054        self.reordering_threshold = frame.reordering_threshold.into_inner();
-1055    }
-1056
-1057    pub(super) fn set_immediate_ack_required(&mut self) {
-1058        self.immediate_ack_required = true;
-1059    }
-1060
-1061    pub(super) fn on_max_ack_delay_timeout(&mut self) {
-1062        self.immediate_ack_required = self.ack_eliciting_since_last_ack_sent > 0;
-1063    }
-1064
-1065    pub(super) fn max_ack_delay_timeout(&self, max_ack_delay: Duration) -> Option<Instant> {
-1066        self.earliest_ack_eliciting_since_last_ack_sent
-1067            .map(|earliest_unacked| earliest_unacked + max_ack_delay)
-1068    }
-1069
-1070    /// Whether any ACK frames SHOULD be sent
-1071    ///
-1072    /// This is used in the top-level [`Connection::space_can_send`], so determines if a
-1073    /// packet will be built. It is often possible to construct new ACK ranges to send
-1074    /// before this returns `true`. This results in more ACK frames being sent, and
-1075    /// processing those at the receiver costs CPU for very little improvements.
-1076    ///
-1077    /// [`Connection::space_can_send`]: super::Connection::space_can_send
-1078    pub(super) fn can_send(&self) -> bool {
-1079        self.immediate_ack_required && !self.ranges.is_empty()
-1080    }
-1081
-1082    /// Returns the delay since the packet with the largest packet number was received
-1083    pub(super) fn ack_delay(&self, now: Instant) -> Duration {
-1084        self.largest_packet
-1085            .map_or_else(Duration::default, |(_, received)| now - received)
-1086    }
-1087
-1088    /// Handle receipt of a new packet
-1089    ///
-1090    /// Returns true if the max ack delay timer should be armed
-1091    pub(super) fn packet_received(
-1092        &mut self,
-1093        now: Instant,
-1094        packet_number: u64,
-1095        ack_eliciting: bool,
-1096        dedup: &Dedup,
-1097    ) -> bool {
-1098        if !ack_eliciting {
-1099            self.non_ack_eliciting_since_last_ack_sent += 1;
-1100            return false;
-1101        }
+953        let smallest_missing_offset = 128 - gaps.leading_zeros() as u64;
+954        let smallest_missing_packet = self.highest() - smallest_missing_offset;
+955
+956        if smallest_missing_packet <= upper_bound {
+957            Some(smallest_missing_packet)
+958        } else {
+959            None
+960        }
+961    }
+962
+963    /// Returns true if there are any missing packets between the provided interval
+964    ///
+965    /// The provided packet numbers must have been received before calling this function
+966    fn missing_in_interval(&self, lower_bound: u64, upper_bound: u64) -> bool {
+967        self.smallest_missing_in_interval(lower_bound, upper_bound)
+968            .is_some()
+969    }
+970}
+971
+972/// Indicates which data is available for sending.
+973///
+974/// This applies to a particular space ID that was queried and all refers to on-path data.
+975#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+976pub(super) struct SendableFrames {
+977    /// Whether there are ACK frames to send, these are not ack-eliciting.
+978    pub(super) acks: bool,
+979    /// Whether there is a CONNECTION_CLOSE to send, this is not ack-eliciting.
+980    pub(super) close: bool,
+981    /// Whether there are any frames that must be sent on this specific space.
+982    ///
+983    /// A space here in the sense of a QUIC Multipath packet number space: `Initial`,
+984    /// `Handshake` and all `Data(PathId)` spaces.
+985    ///
+986    /// These are ack-eliciting. Some frames are scheduled per path, e.g. PING,
+987    /// IMMEDIATE_ACK, PATH_CHALLENGE or PATH_RESPONSE.
+988    pub(super) space_specific: bool,
+989    /// Whether there are any other frames to send, these are ack-eliciting.
+990    pub(super) other: bool,
+991}
+992
+993impl SendableFrames {
+994    /// Returns that no data is available for sending
+995    pub(super) fn empty() -> Self {
+996        Self {
+997            acks: false,
+998            close: false,
+999            space_specific: false,
+1000            other: false,
+1001        }
+1002    }
+1003
+1004    /// Whether an ack-eliciting packet will be sent.
+1005    pub(super) fn is_ack_eliciting(&self) -> bool {
+1006        let Self {
+1007            acks: _,
+1008            close,
+1009            space_specific,
+1010            other,
+1011        } = *self;
+1012        if close {
+1013            // No ack-eliciting frames are included with a CONNECTION_CLOSE, only acks.
+1014            return false;
+1015        }
+1016        space_specific || other
+1017    }
+1018
+1019    /// Whether no data is sendable.
+1020    pub(super) fn is_empty(&self) -> bool {
+1021        let Self {
+1022            acks,
+1023            close,
+1024            space_specific,
+1025            other,
+1026        } = *self;
+1027        !acks && !close && !space_specific && !other
+1028    }
+1029}
+1030
+1031impl ::std::ops::BitOrAssign for SendableFrames {
+1032    fn bitor_assign(&mut self, rhs: Self) {
+1033        let Self {
+1034            acks,
+1035            close,
+1036            space_specific,
+1037            other,
+1038        } = rhs;
+1039
+1040        self.acks |= acks;
+1041        self.close |= close;
+1042        self.space_specific |= space_specific;
+1043        self.other |= other;
+1044    }
+1045}
+1046
+1047#[derive(Debug)]
+1048pub(super) struct PendingAcks {
+1049    /// Whether we should send an ACK immediately, even if that means sending an ACK-only packet
+1050    ///
+1051    /// When `immediate_ack_required` is false, the normal behavior is to send ACK frames only when
+1052    /// there is other data to send, or when the `MaxAckDelay` timer expires.
+1053    immediate_ack_required: bool,
+1054    /// The number of ack-eliciting packets received since the last ACK frame was sent
+1055    ///
+1056    /// Once the count _exceeds_ `ack_eliciting_threshold`, an immediate ACK is required
+1057    ack_eliciting_since_last_ack_sent: u64,
+1058    non_ack_eliciting_since_last_ack_sent: u64,
+1059    ack_eliciting_threshold: u64,
+1060    /// The reordering threshold, controlling how we respond to out-of-order ack-eliciting packets
+1061    ///
+1062    /// Different values enable different behavior:
+1063    ///
+1064    /// * `0`: no special action is taken
+1065    /// * `1`: an ACK is immediately sent if it is out-of-order according to RFC 9000
+1066    /// * `>1`: an ACK is immediately sent if it is out-of-order according to the ACK frequency draft
+1067    reordering_threshold: u64,
+1068    /// The earliest ack-eliciting packet since the last ACK was sent, used to calculate the moment
+1069    /// upon which `max_ack_delay` elapses
+1070    earliest_ack_eliciting_since_last_ack_sent: Option<Instant>,
+1071    /// Packet number ranges for which to still send acknowledgements.
+1072    ///
+1073    /// These are packet number ranges of ack-eliciting packets the peer has sent and which
+1074    /// need to be acknowledged.  Packet numbers are only removed from here once the peer has
+1075    /// acknowledged the ACKs for them.
+1076    ranges: ArrayRangeSet,
+1077    /// The largest packet number received and the time it was received
+1078    ///
+1079    /// Used to calculate ACK delay in [`PendingAcks::ack_delay`].
+1080    largest_packet: Option<(u64, Instant)>,
+1081    /// The ack-eliciting packet we have received with the largest packet number
+1082    largest_ack_eliciting_packet: Option<u64>,
+1083    /// The largest acknowledged packet number sent in an ACK frame
+1084    largest_acked: Option<u64>,
+1085}
+1086
+1087impl PendingAcks {
+1088    fn new() -> Self {
+1089        Self {
+1090            immediate_ack_required: false,
+1091            ack_eliciting_since_last_ack_sent: 0,
+1092            non_ack_eliciting_since_last_ack_sent: 0,
+1093            ack_eliciting_threshold: 1,
+1094            reordering_threshold: 1,
+1095            earliest_ack_eliciting_since_last_ack_sent: None,
+1096            ranges: Default::default(),
+1097            largest_packet: Default::default(),
+1098            largest_ack_eliciting_packet: Default::default(),
+1099            largest_acked: Default::default(),
+1100        }
+1101    }
 1102
-1103        let prev_largest_ack_eliciting = self.largest_ack_eliciting_packet.unwrap_or(0);
-1104
-1105        // Track largest ack-eliciting packet
-1106        self.largest_ack_eliciting_packet = self
-1107            .largest_ack_eliciting_packet
-1108            .map(|pn| pn.max(packet_number))
-1109            .or(Some(packet_number));
-1110
-1111        // Handle ack_eliciting_threshold
-1112        self.ack_eliciting_since_last_ack_sent += 1;
-1113        self.immediate_ack_required |=
-1114            self.ack_eliciting_since_last_ack_sent > self.ack_eliciting_threshold;
+1103    pub(super) fn set_ack_frequency_params(&mut self, frame: &frame::AckFrequency) {
+1104        self.ack_eliciting_threshold = frame.ack_eliciting_threshold.into_inner();
+1105        self.reordering_threshold = frame.reordering_threshold.into_inner();
+1106    }
+1107
+1108    pub(super) fn set_immediate_ack_required(&mut self) {
+1109        self.immediate_ack_required = true;
+1110    }
+1111
+1112    pub(super) fn on_max_ack_delay_timeout(&mut self) {
+1113        self.immediate_ack_required = self.ack_eliciting_since_last_ack_sent > 0;
+1114    }
 1115
-1116        // Handle out-of-order packets
-1117        self.immediate_ack_required |=
-1118            self.is_out_of_order(packet_number, prev_largest_ack_eliciting, dedup);
-1119
-1120        // Arm max_ack_delay timer if necessary
-1121        if self.earliest_ack_eliciting_since_last_ack_sent.is_none() && !self.can_send() {
-1122            self.earliest_ack_eliciting_since_last_ack_sent = Some(now);
-1123            return true;
-1124        }
-1125
-1126        false
-1127    }
-1128
-1129    fn is_out_of_order(
-1130        &self,
-1131        packet_number: u64,
-1132        prev_largest_ack_eliciting: u64,
-1133        dedup: &Dedup,
-1134    ) -> bool {
-1135        match self.reordering_threshold {
-1136            0 => false,
-1137            1 => {
-1138                // From https://www.rfc-editor.org/rfc/rfc9000#section-13.2.1-7
-1139                packet_number < prev_largest_ack_eliciting
-1140                    || dedup.missing_in_interval(prev_largest_ack_eliciting, packet_number)
-1141            }
-1142            _ => {
-1143                // From acknowledgement frequency draft, section 6.1: send an ACK immediately if
-1144                // doing so would cause the sender to detect a new packet loss
-1145                let Some((largest_acked, largest_unacked)) =
-1146                    self.largest_acked.zip(self.largest_ack_eliciting_packet)
-1147                else {
-1148                    return false;
-1149                };
-1150                if self.reordering_threshold > largest_acked {
-1151                    return false;
-1152                }
-1153                // The largest packet number that could be declared lost without a new ACK being
-1154                // sent
-1155                let largest_reported = largest_acked - self.reordering_threshold + 1;
-1156                let Some(smallest_missing_unreported) =
-1157                    dedup.smallest_missing_in_interval(largest_reported, largest_unacked)
-1158                else {
-1159                    return false;
-1160                };
-1161                largest_unacked - smallest_missing_unreported >= self.reordering_threshold
-1162            }
-1163        }
-1164    }
-1165
-1166    /// Should be called whenever ACKs have been sent
-1167    ///
-1168    /// This will suppress sending further ACKs until additional ACK eliciting frames arrive
-1169    pub(super) fn acks_sent(&mut self) {
-1170        // It is possible (though unlikely) that the ACKs we just sent do not cover all the
-1171        // ACK-eliciting packets we have received (e.g. if there is not enough room in the packet to
-1172        // fit all the ranges). To keep things simple, however, we assume they do. If there are
-1173        // indeed some ACKs that weren't covered, the packets might be ACKed later anyway, because
-1174        // they are still contained in `self.ranges`. If we somehow fail to send the ACKs at a later
-1175        // moment, the peer will assume the packets got lost and will retransmit their frames in a
-1176        // new packet, which is suboptimal, because we already received them. Our assumption here is
-1177        // that simplicity results in code that is more performant, even in the presence of
-1178        // occasional redundant retransmits.
-1179        self.immediate_ack_required = false;
-1180        self.ack_eliciting_since_last_ack_sent = 0;
-1181        self.non_ack_eliciting_since_last_ack_sent = 0;
-1182        self.earliest_ack_eliciting_since_last_ack_sent = None;
-1183        self.largest_acked = self.largest_ack_eliciting_packet;
-1184    }
-1185
-1186    /// Insert one packet that needs to be acknowledged
-1187    pub(super) fn insert_one(&mut self, packet: u64, now: Instant) {
-1188        self.ranges.insert_one(packet);
-1189
-1190        if self.largest_packet.is_none_or(|(pn, _)| packet > pn) {
-1191            self.largest_packet = Some((packet, now));
-1192        }
-1193
-1194        if self.ranges.len() > MAX_ACK_BLOCKS {
-1195            self.ranges.pop_min();
-1196        }
-1197    }
-1198
-1199    /// Remove ACKs of packets numbered at or below `max` from the set of pending ACKs
-1200    pub(super) fn subtract_below(&mut self, max: u64) {
-1201        self.ranges.remove(0..(max + 1));
-1202    }
-1203
-1204    /// Returns the set of currently pending ACK ranges
-1205    pub(super) fn ranges(&self) -> &ArrayRangeSet {
-1206        &self.ranges
-1207    }
-1208
-1209    /// Queue an ACK if a significant number of non-ACK-eliciting packets have not yet been
-1210    /// acknowledged
-1211    ///
-1212    /// Should be called immediately before a non-probing packet is composed, when we've already
-1213    /// committed to sending a packet regardless.
-1214    pub(super) fn maybe_ack_non_eliciting(&mut self) {
-1215        // If we're going to send a packet anyway, and we've received a significant number of
-1216        // non-ACK-eliciting packets, then include an ACK to help the peer perform timely loss
-1217        // detection even if they're not sending any ACK-eliciting packets themselves. Exact
-1218        // threshold chosen somewhat arbitrarily.
-1219        const LAZY_ACK_THRESHOLD: u64 = 10;
-1220        if self.non_ack_eliciting_since_last_ack_sent > LAZY_ACK_THRESHOLD {
-1221            self.immediate_ack_required = true;
-1222        }
-1223    }
-1224}
-1225
-1226/// Helper for mitigating [optimistic ACK attacks]
-1227///
-1228/// A malicious peer could prompt the local application to begin a large data transfer, and then
-1229/// send ACKs without first waiting for data to be received. This could defeat congestion control,
-1230/// allowing the connection to consume disproportionate resources. We therefore occasionally skip
-1231/// packet numbers, and classify any ACK referencing a skipped packet number as a transport error.
-1232///
-1233/// Skipped packet numbers occur only in the application data space (where costly transfers might
-1234/// take place) and are distributed exponentially to reflect the reduced likelihood and impact of
-1235/// bad behavior from a peer that has been well-behaved for an extended period.
-1236///
-1237/// ACKs for packet numbers that have not yet been allocated are also a transport error, but an
-1238/// attacker with knowledge of the congestion control algorithm in use could time falsified ACKs to
-1239/// arrive after the packets they reference are sent.
-1240///
-1241/// [optimistic ACK attacks]: https://www.rfc-editor.org/rfc/rfc9000.html#name-optimistic-ack-attack
-1242pub(super) struct PacketNumberFilter {
-1243    /// Next outgoing packet number to skip
-1244    next_skipped_packet_number: u64,
-1245    /// Most recently skipped packet number
-1246    prev_skipped_packet_number: Option<u64>,
-1247    /// Next packet number to skip is randomly selected from 2^n..2^n+1
-1248    exponent: u32,
-1249}
-1250
-1251impl PacketNumberFilter {
-1252    pub(super) fn new(rng: &mut (impl CryptoRng + ?Sized)) -> Self {
-1253        // First skipped PN is in 0..64
-1254        let exponent = 6;
-1255        Self {
-1256            next_skipped_packet_number: rng.random_range(0..2u64.saturating_pow(exponent)),
-1257            prev_skipped_packet_number: None,
-1258            exponent,
-1259        }
-1260    }
-1261
-1262    #[cfg(test)]
-1263    pub(super) fn disabled() -> Self {
-1264        Self {
-1265            next_skipped_packet_number: u64::MAX,
-1266            prev_skipped_packet_number: None,
-1267            exponent: u32::MAX,
-1268        }
-1269    }
-1270
-1271    /// Whether to use the provided packet number (false) or to skip it (true)
-1272    pub(super) fn skip_pn(&mut self, n: u64, rng: &mut (impl CryptoRng + ?Sized)) -> bool {
-1273        if n != self.next_skipped_packet_number {
-1274            return false;
-1275        }
+1116    pub(super) fn max_ack_delay_timeout(&self, max_ack_delay: Duration) -> Option<Instant> {
+1117        self.earliest_ack_eliciting_since_last_ack_sent
+1118            .map(|earliest_unacked| earliest_unacked + max_ack_delay)
+1119    }
+1120
+1121    /// Whether any ACK frames SHOULD be sent
+1122    ///
+1123    /// This is used in the top-level [`Connection::space_can_send`], so determines if a
+1124    /// packet will be built. It is often possible to construct new ACK ranges to send
+1125    /// before this returns `true`. This results in more ACK frames being sent, and
+1126    /// processing those at the receiver costs CPU for very little improvements.
+1127    ///
+1128    /// [`Connection::space_can_send`]: super::Connection::space_can_send
+1129    pub(super) fn can_send(&self) -> bool {
+1130        self.immediate_ack_required && !self.ranges.is_empty()
+1131    }
+1132
+1133    /// Returns the delay since the packet with the largest packet number was received
+1134    pub(super) fn ack_delay(&self, now: Instant) -> Duration {
+1135        self.largest_packet
+1136            .map_or_else(Duration::default, |(_, received)| now - received)
+1137    }
+1138
+1139    /// Handle receipt of a new packet
+1140    ///
+1141    /// Returns true if the max ack delay timer should be armed
+1142    pub(super) fn packet_received(
+1143        &mut self,
+1144        now: Instant,
+1145        packet_number: u64,
+1146        ack_eliciting: bool,
+1147        dedup: &Dedup,
+1148    ) -> bool {
+1149        if !ack_eliciting {
+1150            self.non_ack_eliciting_since_last_ack_sent += 1;
+1151            return false;
+1152        }
+1153
+1154        let prev_largest_ack_eliciting = self.largest_ack_eliciting_packet.unwrap_or(0);
+1155
+1156        // Track largest ack-eliciting packet
+1157        self.largest_ack_eliciting_packet = self
+1158            .largest_ack_eliciting_packet
+1159            .map(|pn| pn.max(packet_number))
+1160            .or(Some(packet_number));
+1161
+1162        // Handle ack_eliciting_threshold
+1163        self.ack_eliciting_since_last_ack_sent += 1;
+1164        self.immediate_ack_required |=
+1165            self.ack_eliciting_since_last_ack_sent > self.ack_eliciting_threshold;
+1166
+1167        // Handle out-of-order packets
+1168        self.immediate_ack_required |=
+1169            self.is_out_of_order(packet_number, prev_largest_ack_eliciting, dedup);
+1170
+1171        // Arm max_ack_delay timer if necessary
+1172        if self.earliest_ack_eliciting_since_last_ack_sent.is_none() && !self.can_send() {
+1173            self.earliest_ack_eliciting_since_last_ack_sent = Some(now);
+1174            return true;
+1175        }
+1176
+1177        false
+1178    }
+1179
+1180    fn is_out_of_order(
+1181        &self,
+1182        packet_number: u64,
+1183        prev_largest_ack_eliciting: u64,
+1184        dedup: &Dedup,
+1185    ) -> bool {
+1186        match self.reordering_threshold {
+1187            0 => false,
+1188            1 => {
+1189                // From https://www.rfc-editor.org/rfc/rfc9000#section-13.2.1-7
+1190                packet_number < prev_largest_ack_eliciting
+1191                    || dedup.missing_in_interval(prev_largest_ack_eliciting, packet_number)
+1192            }
+1193            _ => {
+1194                // From acknowledgement frequency draft, section 6.1: send an ACK immediately if
+1195                // doing so would cause the sender to detect a new packet loss
+1196                let Some((largest_acked, largest_unacked)) =
+1197                    self.largest_acked.zip(self.largest_ack_eliciting_packet)
+1198                else {
+1199                    return false;
+1200                };
+1201                if self.reordering_threshold > largest_acked {
+1202                    return false;
+1203                }
+1204                // The largest packet number that could be declared lost without a new ACK being
+1205                // sent
+1206                let largest_reported = largest_acked - self.reordering_threshold + 1;
+1207                let Some(smallest_missing_unreported) =
+1208                    dedup.smallest_missing_in_interval(largest_reported, largest_unacked)
+1209                else {
+1210                    return false;
+1211                };
+1212                largest_unacked - smallest_missing_unreported >= self.reordering_threshold
+1213            }
+1214        }
+1215    }
+1216
+1217    /// Should be called whenever ACKs have been sent
+1218    ///
+1219    /// This will suppress sending further ACKs until additional ACK eliciting frames arrive
+1220    pub(super) fn acks_sent(&mut self) {
+1221        // It is possible (though unlikely) that the ACKs we just sent do not cover all the
+1222        // ACK-eliciting packets we have received (e.g. if there is not enough room in the packet to
+1223        // fit all the ranges). To keep things simple, however, we assume they do. If there are
+1224        // indeed some ACKs that weren't covered, the packets might be ACKed later anyway, because
+1225        // they are still contained in `self.ranges`. If we somehow fail to send the ACKs at a later
+1226        // moment, the peer will assume the packets got lost and will retransmit their frames in a
+1227        // new packet, which is suboptimal, because we already received them. Our assumption here is
+1228        // that simplicity results in code that is more performant, even in the presence of
+1229        // occasional redundant retransmits.
+1230        self.immediate_ack_required = false;
+1231        self.ack_eliciting_since_last_ack_sent = 0;
+1232        self.non_ack_eliciting_since_last_ack_sent = 0;
+1233        self.earliest_ack_eliciting_since_last_ack_sent = None;
+1234        self.largest_acked = self.largest_ack_eliciting_packet;
+1235    }
+1236
+1237    /// Insert one packet that needs to be acknowledged
+1238    pub(super) fn insert_one(&mut self, packet: u64, now: Instant) {
+1239        self.ranges.insert_one(packet);
+1240
+1241        if self.largest_packet.is_none_or(|(pn, _)| packet > pn) {
+1242            self.largest_packet = Some((packet, now));
+1243        }
+1244
+1245        if self.ranges.len() > MAX_ACK_BLOCKS {
+1246            self.ranges.pop_min();
+1247        }
+1248    }
+1249
+1250    /// Remove ACKs of packets numbered at or below `max` from the set of pending ACKs
+1251    pub(super) fn subtract_below(&mut self, max: u64) {
+1252        self.ranges.remove(0..(max + 1));
+1253    }
+1254
+1255    /// Returns the set of currently pending ACK ranges
+1256    pub(super) fn ranges(&self) -> &ArrayRangeSet {
+1257        &self.ranges
+1258    }
+1259
+1260    /// Queue an ACK if a significant number of non-ACK-eliciting packets have not yet been
+1261    /// acknowledged
+1262    ///
+1263    /// Should be called immediately before a non-probing packet is composed, when we've already
+1264    /// committed to sending a packet regardless.
+1265    pub(super) fn maybe_ack_non_eliciting(&mut self) {
+1266        // If we're going to send a packet anyway, and we've received a significant number of
+1267        // non-ACK-eliciting packets, then include an ACK to help the peer perform timely loss
+1268        // detection even if they're not sending any ACK-eliciting packets themselves. Exact
+1269        // threshold chosen somewhat arbitrarily.
+1270        const LAZY_ACK_THRESHOLD: u64 = 10;
+1271        if self.non_ack_eliciting_since_last_ack_sent > LAZY_ACK_THRESHOLD {
+1272            self.immediate_ack_required = true;
+1273        }
+1274    }
+1275}
 1276
-1277        trace!("skipping pn {n}");
-1278        // Skip this packet number, and choose the next one to skip
-1279        self.prev_skipped_packet_number = Some(self.next_skipped_packet_number);
-1280        let next_exponent = self.exponent.saturating_add(1);
-1281        self.next_skipped_packet_number = rng
-1282            .random_range(2u64.saturating_pow(self.exponent)..2u64.saturating_pow(next_exponent));
-1283        self.exponent = next_exponent;
-1284        true
-1285    }
-1286}
-1287
-1288/// Ensures we can always fit all our ACKs in a single minimum-MTU packet with room to spare
-1289const MAX_ACK_BLOCKS: usize = 64;
-1290
-1291#[cfg(test)]
-1292mod test {
-1293    use rand::Rng;
-1294    use rand::seq::SliceRandom;
-1295
-1296    use crate::token::ResetToken;
-1297    use crate::{ConnectionIdGenerator, RandomConnectionIdGenerator};
-1298
-1299    use super::*;
-1300
-1301    #[test]
-1302    fn sanity() {
-1303        let mut dedup = Dedup::new();
-1304        assert!(!dedup.insert(0));
-1305        assert_eq!(dedup.next, 1);
-1306        assert_eq!(dedup.window, 0b1);
-1307        assert!(dedup.insert(0));
-1308        assert_eq!(dedup.next, 1);
-1309        assert_eq!(dedup.window, 0b1);
-1310        assert!(!dedup.insert(1));
-1311        assert_eq!(dedup.next, 2);
-1312        assert_eq!(dedup.window, 0b11);
-1313        assert!(!dedup.insert(2));
-1314        assert_eq!(dedup.next, 3);
-1315        assert_eq!(dedup.window, 0b111);
-1316        assert!(!dedup.insert(4));
-1317        assert_eq!(dedup.next, 5);
-1318        assert_eq!(dedup.window, 0b11110);
-1319        assert!(!dedup.insert(7));
-1320        assert_eq!(dedup.next, 8);
-1321        assert_eq!(dedup.window, 0b1111_0100);
-1322        assert!(dedup.insert(4));
-1323        assert!(!dedup.insert(3));
-1324        assert_eq!(dedup.next, 8);
-1325        assert_eq!(dedup.window, 0b1111_1100);
-1326        assert!(!dedup.insert(6));
-1327        assert_eq!(dedup.next, 8);
-1328        assert_eq!(dedup.window, 0b1111_1101);
-1329        assert!(!dedup.insert(5));
-1330        assert_eq!(dedup.next, 8);
-1331        assert_eq!(dedup.window, 0b1111_1111);
-1332    }
-1333
-1334    #[test]
-1335    fn happypath() {
-1336        let mut dedup = Dedup::new();
-1337        for i in 0..(2 * WINDOW_SIZE) {
-1338            assert!(!dedup.insert(i));
-1339            for j in 0..=i {
-1340                assert!(dedup.insert(j));
-1341            }
-1342        }
-1343    }
-1344
-1345    #[test]
-1346    fn jump() {
-1347        let mut dedup = Dedup::new();
-1348        dedup.insert(2 * WINDOW_SIZE);
-1349        assert!(dedup.insert(WINDOW_SIZE));
-1350        assert_eq!(dedup.next, 2 * WINDOW_SIZE + 1);
-1351        assert_eq!(dedup.window, 0);
-1352        assert!(!dedup.insert(WINDOW_SIZE + 1));
-1353        assert_eq!(dedup.next, 2 * WINDOW_SIZE + 1);
-1354        assert_eq!(dedup.window, 1 << (WINDOW_SIZE - 2));
-1355    }
-1356
-1357    #[test]
-1358    fn dedup_has_missing() {
-1359        let mut dedup = Dedup::new();
-1360
-1361        dedup.insert(0);
-1362        assert!(!dedup.missing_in_interval(0, 0));
-1363
-1364        dedup.insert(1);
-1365        assert!(!dedup.missing_in_interval(0, 1));
-1366
-1367        dedup.insert(3);
-1368        assert!(dedup.missing_in_interval(1, 3));
-1369
-1370        dedup.insert(4);
-1371        assert!(!dedup.missing_in_interval(3, 4));
-1372        assert!(dedup.missing_in_interval(0, 4));
-1373
-1374        dedup.insert(2);
-1375        assert!(!dedup.missing_in_interval(0, 4));
-1376    }
-1377
-1378    #[test]
-1379    fn dedup_outside_of_window_has_missing() {
-1380        let mut dedup = Dedup::new();
-1381
-1382        for i in 0..140 {
-1383            dedup.insert(i);
-1384        }
-1385
-1386        // 0 and 4 are outside of the window
-1387        assert!(!dedup.missing_in_interval(0, 4));
-1388        dedup.insert(160);
-1389        assert!(!dedup.missing_in_interval(0, 4));
-1390        assert!(!dedup.missing_in_interval(0, 140));
-1391        assert!(dedup.missing_in_interval(0, 160));
-1392    }
-1393
-1394    #[test]
-1395    fn dedup_smallest_missing() {
-1396        let mut dedup = Dedup::new();
-1397
-1398        dedup.insert(0);
-1399        assert_eq!(dedup.smallest_missing_in_interval(0, 0), None);
-1400
-1401        dedup.insert(1);
-1402        assert_eq!(dedup.smallest_missing_in_interval(0, 1), None);
-1403
-1404        dedup.insert(5);
-1405        dedup.insert(7);
-1406        assert_eq!(dedup.smallest_missing_in_interval(0, 7), Some(2));
-1407        assert_eq!(dedup.smallest_missing_in_interval(5, 7), Some(6));
-1408
-1409        dedup.insert(2);
-1410        assert_eq!(dedup.smallest_missing_in_interval(1, 7), Some(3));
+1277/// Helper for mitigating [optimistic ACK attacks]
+1278///
+1279/// A malicious peer could prompt the local application to begin a large data transfer, and then
+1280/// send ACKs without first waiting for data to be received. This could defeat congestion control,
+1281/// allowing the connection to consume disproportionate resources. We therefore occasionally skip
+1282/// packet numbers, and classify any ACK referencing a skipped packet number as a transport error.
+1283///
+1284/// Skipped packet numbers occur only in the application data space (where costly transfers might
+1285/// take place) and are distributed exponentially to reflect the reduced likelihood and impact of
+1286/// bad behavior from a peer that has been well-behaved for an extended period.
+1287///
+1288/// ACKs for packet numbers that have not yet been allocated are also a transport error, but an
+1289/// attacker with knowledge of the congestion control algorithm in use could time falsified ACKs to
+1290/// arrive after the packets they reference are sent.
+1291///
+1292/// [optimistic ACK attacks]: https://www.rfc-editor.org/rfc/rfc9000.html#name-optimistic-ack-attack
+1293pub(super) struct PacketNumberFilter {
+1294    /// Next outgoing packet number to skip
+1295    next_skipped_packet_number: u64,
+1296    /// Most recently skipped packet number
+1297    prev_skipped_packet_number: Option<u64>,
+1298    /// Next packet number to skip is randomly selected from 2^n..2^n+1
+1299    exponent: u32,
+1300}
+1301
+1302impl PacketNumberFilter {
+1303    pub(super) fn new(rng: &mut (impl CryptoRng + ?Sized)) -> Self {
+1304        // First skipped PN is in 0..64
+1305        let exponent = 6;
+1306        Self {
+1307            next_skipped_packet_number: rng.random_range(0..2u64.saturating_pow(exponent)),
+1308            prev_skipped_packet_number: None,
+1309            exponent,
+1310        }
+1311    }
+1312
+1313    #[cfg(test)]
+1314    pub(super) fn disabled() -> Self {
+1315        Self {
+1316            next_skipped_packet_number: u64::MAX,
+1317            prev_skipped_packet_number: None,
+1318            exponent: u32::MAX,
+1319        }
+1320    }
+1321
+1322    /// Whether to use the provided packet number (false) or to skip it (true)
+1323    pub(super) fn skip_pn(&mut self, n: u64, rng: &mut (impl CryptoRng + ?Sized)) -> bool {
+1324        if n != self.next_skipped_packet_number {
+1325            return false;
+1326        }
+1327
+1328        trace!("skipping pn {n}");
+1329        // Skip this packet number, and choose the next one to skip
+1330        self.prev_skipped_packet_number = Some(self.next_skipped_packet_number);
+1331        let next_exponent = self.exponent.saturating_add(1);
+1332        self.next_skipped_packet_number = rng
+1333            .random_range(2u64.saturating_pow(self.exponent)..2u64.saturating_pow(next_exponent));
+1334        self.exponent = next_exponent;
+1335        true
+1336    }
+1337}
+1338
+1339/// Ensures we can always fit all our ACKs in a single minimum-MTU packet with room to spare
+1340const MAX_ACK_BLOCKS: usize = 64;
+1341
+1342#[cfg(test)]
+1343mod test {
+1344    use rand::Rng;
+1345    use rand::seq::SliceRandom;
+1346
+1347    use crate::token::ResetToken;
+1348    use crate::{ConnectionIdGenerator, RandomConnectionIdGenerator};
+1349
+1350    use super::*;
+1351
+1352    #[test]
+1353    fn sanity() {
+1354        let mut dedup = Dedup::new();
+1355        assert!(!dedup.insert(0));
+1356        assert_eq!(dedup.next, 1);
+1357        assert_eq!(dedup.window, 0b1);
+1358        assert!(dedup.insert(0));
+1359        assert_eq!(dedup.next, 1);
+1360        assert_eq!(dedup.window, 0b1);
+1361        assert!(!dedup.insert(1));
+1362        assert_eq!(dedup.next, 2);
+1363        assert_eq!(dedup.window, 0b11);
+1364        assert!(!dedup.insert(2));
+1365        assert_eq!(dedup.next, 3);
+1366        assert_eq!(dedup.window, 0b111);
+1367        assert!(!dedup.insert(4));
+1368        assert_eq!(dedup.next, 5);
+1369        assert_eq!(dedup.window, 0b11110);
+1370        assert!(!dedup.insert(7));
+1371        assert_eq!(dedup.next, 8);
+1372        assert_eq!(dedup.window, 0b1111_0100);
+1373        assert!(dedup.insert(4));
+1374        assert!(!dedup.insert(3));
+1375        assert_eq!(dedup.next, 8);
+1376        assert_eq!(dedup.window, 0b1111_1100);
+1377        assert!(!dedup.insert(6));
+1378        assert_eq!(dedup.next, 8);
+1379        assert_eq!(dedup.window, 0b1111_1101);
+1380        assert!(!dedup.insert(5));
+1381        assert_eq!(dedup.next, 8);
+1382        assert_eq!(dedup.window, 0b1111_1111);
+1383    }
+1384
+1385    #[test]
+1386    fn happypath() {
+1387        let mut dedup = Dedup::new();
+1388        for i in 0..(2 * WINDOW_SIZE) {
+1389            assert!(!dedup.insert(i));
+1390            for j in 0..=i {
+1391                assert!(dedup.insert(j));
+1392            }
+1393        }
+1394    }
+1395
+1396    #[test]
+1397    fn jump() {
+1398        let mut dedup = Dedup::new();
+1399        dedup.insert(2 * WINDOW_SIZE);
+1400        assert!(dedup.insert(WINDOW_SIZE));
+1401        assert_eq!(dedup.next, 2 * WINDOW_SIZE + 1);
+1402        assert_eq!(dedup.window, 0);
+1403        assert!(!dedup.insert(WINDOW_SIZE + 1));
+1404        assert_eq!(dedup.next, 2 * WINDOW_SIZE + 1);
+1405        assert_eq!(dedup.window, 1 << (WINDOW_SIZE - 2));
+1406    }
+1407
+1408    #[test]
+1409    fn dedup_has_missing() {
+1410        let mut dedup = Dedup::new();
 1411
-1412        dedup.insert(170);
-1413        dedup.insert(172);
-1414        dedup.insert(300);
-1415        assert_eq!(dedup.smallest_missing_in_interval(170, 172), None);
-1416
-1417        dedup.insert(500);
-1418        assert_eq!(dedup.smallest_missing_in_interval(0, 500), Some(372));
-1419        assert_eq!(dedup.smallest_missing_in_interval(0, 373), Some(372));
-1420        assert_eq!(dedup.smallest_missing_in_interval(0, 372), None);
-1421    }
-1422
-1423    #[test]
-1424    fn pending_acks_first_packet_is_not_considered_reordered() {
-1425        let mut acks = PendingAcks::new();
-1426        let mut dedup = Dedup::new();
-1427        dedup.insert(0);
-1428        acks.packet_received(Instant::now(), 0, true, &dedup);
-1429        assert!(!acks.immediate_ack_required);
-1430    }
-1431
-1432    #[test]
-1433    fn pending_acks_after_immediate_ack_set() {
-1434        let mut acks = PendingAcks::new();
-1435        let mut dedup = Dedup::new();
+1412        dedup.insert(0);
+1413        assert!(!dedup.missing_in_interval(0, 0));
+1414
+1415        dedup.insert(1);
+1416        assert!(!dedup.missing_in_interval(0, 1));
+1417
+1418        dedup.insert(3);
+1419        assert!(dedup.missing_in_interval(1, 3));
+1420
+1421        dedup.insert(4);
+1422        assert!(!dedup.missing_in_interval(3, 4));
+1423        assert!(dedup.missing_in_interval(0, 4));
+1424
+1425        dedup.insert(2);
+1426        assert!(!dedup.missing_in_interval(0, 4));
+1427    }
+1428
+1429    #[test]
+1430    fn dedup_outside_of_window_has_missing() {
+1431        let mut dedup = Dedup::new();
+1432
+1433        for i in 0..140 {
+1434            dedup.insert(i);
+1435        }
 1436
-1437        // Receive ack-eliciting packet
-1438        dedup.insert(0);
-1439        let now = Instant::now();
-1440        acks.insert_one(0, now);
-1441        acks.packet_received(now, 0, true, &dedup);
-1442
-1443        // Sanity check
-1444        assert!(!acks.ranges.is_empty());
-1445        assert!(!acks.can_send());
-1446
-1447        // Can send ACK after max_ack_delay exceeded
-1448        acks.set_immediate_ack_required();
-1449        assert!(acks.can_send());
-1450    }
+1437        // 0 and 4 are outside of the window
+1438        assert!(!dedup.missing_in_interval(0, 4));
+1439        dedup.insert(160);
+1440        assert!(!dedup.missing_in_interval(0, 4));
+1441        assert!(!dedup.missing_in_interval(0, 140));
+1442        assert!(dedup.missing_in_interval(0, 160));
+1443    }
+1444
+1445    #[test]
+1446    fn dedup_smallest_missing() {
+1447        let mut dedup = Dedup::new();
+1448
+1449        dedup.insert(0);
+1450        assert_eq!(dedup.smallest_missing_in_interval(0, 0), None);
 1451
-1452    #[test]
-1453    fn pending_acks_ack_delay() {
-1454        let mut acks = PendingAcks::new();
-1455        let mut dedup = Dedup::new();
-1456
-1457        let t1 = Instant::now();
-1458        let t2 = t1 + Duration::from_millis(2);
-1459        let t3 = t2 + Duration::from_millis(5);
-1460        assert_eq!(acks.ack_delay(t1), Duration::from_millis(0));
-1461        assert_eq!(acks.ack_delay(t2), Duration::from_millis(0));
-1462        assert_eq!(acks.ack_delay(t3), Duration::from_millis(0));
-1463
-1464        // In-order packet
-1465        dedup.insert(0);
-1466        acks.insert_one(0, t1);
-1467        acks.packet_received(t1, 0, true, &dedup);
-1468        assert_eq!(acks.ack_delay(t1), Duration::from_millis(0));
-1469        assert_eq!(acks.ack_delay(t2), Duration::from_millis(2));
-1470        assert_eq!(acks.ack_delay(t3), Duration::from_millis(7));
-1471
-1472        // Out of order (higher than expected)
-1473        dedup.insert(3);
-1474        acks.insert_one(3, t2);
-1475        acks.packet_received(t2, 3, true, &dedup);
-1476        assert_eq!(acks.ack_delay(t2), Duration::from_millis(0));
-1477        assert_eq!(acks.ack_delay(t3), Duration::from_millis(5));
-1478
-1479        // Out of order (lower than expected, so previous instant is kept)
-1480        dedup.insert(2);
-1481        acks.insert_one(2, t3);
-1482        acks.packet_received(t3, 2, true, &dedup);
-1483        assert_eq!(acks.ack_delay(t3), Duration::from_millis(5));
-1484    }
-1485
-1486    #[test]
-1487    fn sent_packet_size() {
-1488        // The tracking state of sent packets should be minimal, and not grow
-1489        // over time.
-1490        assert!(std::mem::size_of::<SentPacket>() <= 128);
-1491    }
-1492
-1493    #[test]
-1494    fn pending_new_cids() {
-1495        #[cfg(all(feature = "aws-lc-rs", not(feature = "ring")))]
-1496        use aws_lc_rs::hmac;
-1497        #[cfg(feature = "ring")]
-1498        use ring::hmac;
-1499
-1500        let mut cid_generator = RandomConnectionIdGenerator::new(8);
-1501        let mut reset_key = [0; 64];
-1502        rand::rng().fill_bytes(&mut reset_key);
-1503        let hmac = hmac::Key::new(hmac::HMAC_SHA256, &reset_key);
-1504
-1505        let cid_a = cid_generator.generate_cid();
-1506        let a = IssuedCid {
-1507            path_id: PathId::ZERO,
-1508            sequence: 1,
-1509            id: cid_a,
-1510            reset_token: ResetToken::new(&hmac, cid_a),
-1511        };
-1512        let cid_b = cid_generator.generate_cid();
-1513        let b = IssuedCid {
-1514            path_id: PathId::ZERO,
-1515            sequence: 2,
-1516            id: cid_b,
-1517            reset_token: ResetToken::new(&hmac, cid_b),
-1518        };
-1519        let cid_c = cid_generator.generate_cid();
-1520        let c = IssuedCid {
-1521            path_id: PathId(1),
-1522            sequence: 1,
-1523            id: cid_c,
-1524            reset_token: ResetToken::new(&hmac, cid_c),
-1525        };
-1526
-1527        let mut pending_cids = PendingNewCids::default();
-1528
-1529        for _ in 0..9 {
-1530            // Push CIDs in a random order
-1531            let mut input = vec![a, b, c];
-1532            input.shuffle(&mut rand::rng());
-1533            for cid in input {
-1534                pending_cids.push(cid);
-1535            }
+1452        dedup.insert(1);
+1453        assert_eq!(dedup.smallest_missing_in_interval(0, 1), None);
+1454
+1455        dedup.insert(5);
+1456        dedup.insert(7);
+1457        assert_eq!(dedup.smallest_missing_in_interval(0, 7), Some(2));
+1458        assert_eq!(dedup.smallest_missing_in_interval(5, 7), Some(6));
+1459
+1460        dedup.insert(2);
+1461        assert_eq!(dedup.smallest_missing_in_interval(1, 7), Some(3));
+1462
+1463        dedup.insert(170);
+1464        dedup.insert(172);
+1465        dedup.insert(300);
+1466        assert_eq!(dedup.smallest_missing_in_interval(170, 172), None);
+1467
+1468        dedup.insert(500);
+1469        assert_eq!(dedup.smallest_missing_in_interval(0, 500), Some(372));
+1470        assert_eq!(dedup.smallest_missing_in_interval(0, 373), Some(372));
+1471        assert_eq!(dedup.smallest_missing_in_interval(0, 372), None);
+1472    }
+1473
+1474    #[test]
+1475    fn pending_acks_first_packet_is_not_considered_reordered() {
+1476        let mut acks = PendingAcks::new();
+1477        let mut dedup = Dedup::new();
+1478        dedup.insert(0);
+1479        acks.packet_received(Instant::now(), 0, true, &dedup);
+1480        assert!(!acks.immediate_ack_required);
+1481    }
+1482
+1483    #[test]
+1484    fn pending_acks_after_immediate_ack_set() {
+1485        let mut acks = PendingAcks::new();
+1486        let mut dedup = Dedup::new();
+1487
+1488        // Receive ack-eliciting packet
+1489        dedup.insert(0);
+1490        let now = Instant::now();
+1491        acks.insert_one(0, now);
+1492        acks.packet_received(now, 0, true, &dedup);
+1493
+1494        // Sanity check
+1495        assert!(!acks.ranges.is_empty());
+1496        assert!(!acks.can_send());
+1497
+1498        // Can send ACK after max_ack_delay exceeded
+1499        acks.set_immediate_ack_required();
+1500        assert!(acks.can_send());
+1501    }
+1502
+1503    #[test]
+1504    fn pending_acks_ack_delay() {
+1505        let mut acks = PendingAcks::new();
+1506        let mut dedup = Dedup::new();
+1507
+1508        let t1 = Instant::now();
+1509        let t2 = t1 + Duration::from_millis(2);
+1510        let t3 = t2 + Duration::from_millis(5);
+1511        assert_eq!(acks.ack_delay(t1), Duration::from_millis(0));
+1512        assert_eq!(acks.ack_delay(t2), Duration::from_millis(0));
+1513        assert_eq!(acks.ack_delay(t3), Duration::from_millis(0));
+1514
+1515        // In-order packet
+1516        dedup.insert(0);
+1517        acks.insert_one(0, t1);
+1518        acks.packet_received(t1, 0, true, &dedup);
+1519        assert_eq!(acks.ack_delay(t1), Duration::from_millis(0));
+1520        assert_eq!(acks.ack_delay(t2), Duration::from_millis(2));
+1521        assert_eq!(acks.ack_delay(t3), Duration::from_millis(7));
+1522
+1523        // Out of order (higher than expected)
+1524        dedup.insert(3);
+1525        acks.insert_one(3, t2);
+1526        acks.packet_received(t2, 3, true, &dedup);
+1527        assert_eq!(acks.ack_delay(t2), Duration::from_millis(0));
+1528        assert_eq!(acks.ack_delay(t3), Duration::from_millis(5));
+1529
+1530        // Out of order (lower than expected, so previous instant is kept)
+1531        dedup.insert(2);
+1532        acks.insert_one(2, t3);
+1533        acks.packet_received(t3, 2, true, &dedup);
+1534        assert_eq!(acks.ack_delay(t3), Duration::from_millis(5));
+1535    }
 1536
-1537            // Pop order is always the same
-1538            assert_eq!(pending_cids.pop().map(|i| i.id), Some(a.id));
-1539            assert_eq!(pending_cids.pop().map(|i| i.id), Some(b.id));
-1540            assert_eq!(pending_cids.pop().map(|i| i.id), Some(c.id));
-1541            assert!(pending_cids.pop().is_none());
-1542        }
-1543    }
-1544}

\ No newline at end of file
+1537    #[test]
+1538    fn sent_packet_size() {
+1539        // The tracking state of sent packets should be minimal, and not grow
+1540        // over time.
+1541        assert!(std::mem::size_of::<SentPacket>() <= 128);
+1542    }
+1543
+1544    #[test]
+1545    fn pending_new_cids() {
+1546        #[cfg(all(feature = "aws-lc-rs", not(feature = "ring")))]
+1547        use aws_lc_rs::hmac;
+1548        #[cfg(feature = "ring")]
+1549        use ring::hmac;
+1550
+1551        let mut cid_generator = RandomConnectionIdGenerator::new(8);
+1552        let mut reset_key = [0; 64];
+1553        rand::rng().fill_bytes(&mut reset_key);
+1554        let hmac = hmac::Key::new(hmac::HMAC_SHA256, &reset_key);
+1555
+1556        let cid_a = cid_generator.generate_cid();
+1557        let a = IssuedCid {
+1558            path_id: PathId::ZERO,
+1559            sequence: 1,
+1560            id: cid_a,
+1561            reset_token: ResetToken::new(&hmac, cid_a),
+1562        };
+1563        let cid_b = cid_generator.generate_cid();
+1564        let b = IssuedCid {
+1565            path_id: PathId::ZERO,
+1566            sequence: 2,
+1567            id: cid_b,
+1568            reset_token: ResetToken::new(&hmac, cid_b),
+1569        };
+1570        let cid_c = cid_generator.generate_cid();
+1571        let c = IssuedCid {
+1572            path_id: PathId(1),
+1573            sequence: 1,
+1574            id: cid_c,
+1575            reset_token: ResetToken::new(&hmac, cid_c),
+1576        };
+1577
+1578        let mut pending_cids = PendingNewCids::default();
+1579
+1580        for _ in 0..9 {
+1581            // Push CIDs in a random order
+1582            let mut input = vec![a, b, c];
+1583            input.shuffle(&mut rand::rng());
+1584            for cid in input {
+1585                pending_cids.push(cid);
+1586            }
+1587
+1588            // Pop order is always the same
+1589            assert_eq!(pending_cids.pop().map(|i| i.id), Some(a.id));
+1590            assert_eq!(pending_cids.pop().map(|i| i.id), Some(b.id));
+1591            assert_eq!(pending_cids.pop().map(|i| i.id), Some(c.id));
+1592            assert!(pending_cids.pop().is_none());
+1593        }
+1594    }
+1595}

\ No newline at end of file
diff --git a/pr/616/docs/src/noq_proto/frame.rs.html b/pr/616/docs/src/noq_proto/frame.rs.html
index c8853decc..3a12df1b4 100644
--- a/pr/616/docs/src/noq_proto/frame.rs.html
+++ b/pr/616/docs/src/noq_proto/frame.rs.html
@@ -2370,511 +2370,498 @@
 2370    }
 2371}
 2372
-2373/// Conjunction of the information contained in the reach out frames
-2374/// ([`FrameType::ReachOutAtIpv4`], [`FrameType::ReachOutAtIpv6`])
-2375#[derive(Debug, PartialEq, Eq, Clone, derive_more::Display)]
-2376#[display("REACH_OUT round: {round} local_addr: {}", self.socket_addr())]
-2377#[cfg_attr(test, derive(Arbitrary))]
-2378pub(crate) struct ReachOut {
-2379    /// The sequence number of the NAT Traversal attempts
-2380    pub(crate) round: VarInt,
-2381    /// Address to use
-2382    pub(crate) ip: IpAddr,
-2383    /// Port to use with this address
-2384    pub(crate) port: u16,
-2385}
-2386
-2387// TODO(@divma): remove
-2388#[allow(dead_code)]
-2389impl ReachOut {
-2390    /// Smallest number of bytes this type of frame is guaranteed to fit within
-2391    pub(crate) const SIZE_BOUND: usize = Self {
-2392        round: VarInt::MAX,
-2393        ip: IpAddr::V6(std::net::Ipv6Addr::LOCALHOST),
-2394        port: u16::MAX,
-2395    }
-2396    .size();
+2373/// Conjunction of the information contained in the reach out frames.
+2374///
+2375/// ([`FrameType::ReachOutAtIpv4`], [`FrameType::ReachOutAtIpv6`])
+2376#[derive(Debug, PartialEq, Eq, Clone, derive_more::Display)]
+2377#[display("REACH_OUT round: {round} local_addr: {}", self.socket_addr())]
+2378#[cfg_attr(test, derive(Arbitrary))]
+2379pub(crate) struct ReachOut {
+2380    /// The sequence number of the NAT Traversal attempts
+2381    pub(crate) round: VarInt,
+2382    /// Address to use
+2383    pub(crate) ip: IpAddr,
+2384    /// Port to use with this address
+2385    pub(crate) port: u16,
+2386}
+2387
+2388impl ReachOut {
+2389    /// Get the [`FrameType`] for this frame
+2390    pub(crate) const fn get_type(&self) -> FrameType {
+2391        if self.ip.is_ipv6() {
+2392            FrameType::ReachOutAtIpv6
+2393        } else {
+2394            FrameType::ReachOutAtIpv4
+2395        }
+2396    }
 2397
-2398    pub(crate) const fn new(round: VarInt, (ip, port): (IpAddr, u16)) -> Self {
-2399        Self { round, ip, port }
-2400    }
-2401
-2402    /// Get the [`FrameType`] for this frame
-2403    pub(crate) const fn get_type(&self) -> FrameType {
-2404        if self.ip.is_ipv6() {
-2405            FrameType::ReachOutAtIpv6
-2406        } else {
-2407            FrameType::ReachOutAtIpv4
-2408        }
-2409    }
-2410
-2411    /// Compute the number of bytes needed to encode the frame
-2412    pub(crate) const fn size(&self) -> usize {
-2413        let type_size = self.get_type().size();
-2414        let round_bytes = self.round.size();
-2415        let ip_bytes = if self.ip.is_ipv6() { 16 } else { 4 };
-2416        let port_bytes = 2;
-2417        type_size + round_bytes + ip_bytes + port_bytes
-2418    }
-2419
-2420    /// Read the frame contents from the buffer
-2421    ///
-2422    /// Should only be called when the frame type has been identified as
-2423    /// [`FrameType::ReachOutAtIpv4`] or [`FrameType::ReachOutAtIpv6`].
-2424    pub(crate) fn read<R: Buf>(bytes: &mut R, is_ipv6: bool) -> coding::Result<Self> {
-2425        let round = bytes.get()?;
-2426        let ip = if is_ipv6 {
-2427            IpAddr::V6(bytes.get()?)
-2428        } else {
-2429            IpAddr::V4(bytes.get()?)
-2430        };
-2431        let port = bytes.get()?;
-2432        Ok(Self { round, ip, port })
-2433    }
-2434
-2435    /// Give the [`SocketAddr`] encoded in the frame
-2436    pub(crate) fn socket_addr(&self) -> SocketAddr {
-2437        (self.ip, self.port).into()
-2438    }
-2439}
-2440
-2441impl Encodable for ReachOut {
-2442    fn encode<W: BufMut>(&self, buf: &mut W) {
-2443        buf.write(self.get_type());
-2444        buf.write(self.round);
-2445        match self.ip {
-2446            IpAddr::V4(ipv4_addr) => {
-2447                buf.write(ipv4_addr);
-2448            }
-2449            IpAddr::V6(ipv6_addr) => {
-2450                buf.write(ipv6_addr);
-2451            }
-2452        }
-2453        buf.write::<u16>(self.port);
-2454    }
-2455}
-2456
-2457/// Frame signaling an address is no longer being advertised
-2458#[derive(Debug, PartialEq, Eq, Copy, Clone, PartialOrd, Ord, derive_more::Display)]
-2459#[cfg_attr(test, derive(Arbitrary))]
-2460#[display("REMOVE_ADDRESS seq_no: {seq_no}")]
-2461pub(crate) struct RemoveAddress {
-2462    /// The sequence number of the address advertisement to be removed
-2463    pub(crate) seq_no: VarInt,
-2464}
+2398    /// Compute the number of bytes needed to encode the frame
+2399    pub(crate) const fn size(&self) -> usize {
+2400        let type_size = self.get_type().size();
+2401        let round_bytes = self.round.size();
+2402        let ip_bytes = if self.ip.is_ipv6() { 16 } else { 4 };
+2403        let port_bytes = 2;
+2404        type_size + round_bytes + ip_bytes + port_bytes
+2405    }
+2406
+2407    /// Read the frame contents from the buffer
+2408    ///
+2409    /// Should only be called when the frame type has been identified as
+2410    /// [`FrameType::ReachOutAtIpv4`] or [`FrameType::ReachOutAtIpv6`].
+2411    pub(crate) fn read<R: Buf>(bytes: &mut R, is_ipv6: bool) -> coding::Result<Self> {
+2412        let round = bytes.get()?;
+2413        let ip = if is_ipv6 {
+2414            IpAddr::V6(bytes.get()?)
+2415        } else {
+2416            IpAddr::V4(bytes.get()?)
+2417        };
+2418        let port = bytes.get()?;
+2419        Ok(Self { round, ip, port })
+2420    }
+2421
+2422    /// Give the [`SocketAddr`] encoded in the frame
+2423    pub(crate) fn socket_addr(&self) -> SocketAddr {
+2424        (self.ip, self.port).into()
+2425    }
+2426}
+2427
+2428impl Encodable for ReachOut {
+2429    fn encode<W: BufMut>(&self, buf: &mut W) {
+2430        buf.write(self.get_type());
+2431        buf.write(self.round);
+2432        match self.ip {
+2433            IpAddr::V4(ipv4_addr) => {
+2434                buf.write(ipv4_addr);
+2435            }
+2436            IpAddr::V6(ipv6_addr) => {
+2437                buf.write(ipv6_addr);
+2438            }
+2439        }
+2440        buf.write::<u16>(self.port);
+2441    }
+2442}
+2443
+2444/// Frame signaling an address is no longer being advertised
+2445#[derive(Debug, PartialEq, Eq, Copy, Clone, PartialOrd, Ord, derive_more::Display)]
+2446#[cfg_attr(test, derive(Arbitrary))]
+2447#[display("REMOVE_ADDRESS seq_no: {seq_no}")]
+2448pub(crate) struct RemoveAddress {
+2449    /// The sequence number of the address advertisement to be removed
+2450    pub(crate) seq_no: VarInt,
+2451}
+2452
+2453// TODO(@divma): remove
+2454#[allow(dead_code)]
+2455impl RemoveAddress {
+2456    /// [`FrameType`] of this frame
+2457    pub(crate) const TYPE: FrameType = FrameType::RemoveAddress;
+2458
+2459    /// Smallest number of bytes this type of frame is guaranteed to fit within
+2460    pub(crate) const SIZE_BOUND: usize = Self::new(VarInt::MAX).size();
+2461
+2462    pub(crate) const fn new(seq_no: VarInt) -> Self {
+2463        Self { seq_no }
+2464    }
 2465
-2466// TODO(@divma): remove
-2467#[allow(dead_code)]
-2468impl RemoveAddress {
-2469    /// [`FrameType`] of this frame
-2470    pub(crate) const TYPE: FrameType = FrameType::RemoveAddress;
-2471
-2472    /// Smallest number of bytes this type of frame is guaranteed to fit within
-2473    pub(crate) const SIZE_BOUND: usize = Self::new(VarInt::MAX).size();
-2474
-2475    pub(crate) const fn new(seq_no: VarInt) -> Self {
-2476        Self { seq_no }
-2477    }
-2478
-2479    /// Compute the number of bytes needed to encode the frame
-2480    pub(crate) const fn size(&self) -> usize {
-2481        let type_size = Self::TYPE.size();
-2482        let seq_no_bytes = self.seq_no.size();
-2483        type_size + seq_no_bytes
-2484    }
-2485
-2486    /// Read the frame contents from the buffer
-2487    ///
-2488    /// Should only be called when the frame type has been identified as
-2489    /// [`FrameType::RemoveAddress`].
-2490    pub(crate) fn read<R: Buf>(bytes: &mut R) -> coding::Result<Self> {
-2491        Ok(Self {
-2492            seq_no: bytes.get()?,
-2493        })
-2494    }
-2495
-2496    const fn get_type(&self) -> FrameType {
-2497        FrameType::RemoveAddress
-2498    }
-2499}
-2500
-2501impl Encodable for RemoveAddress {
-2502    fn encode<W: BufMut>(&self, buf: &mut W) {
-2503        buf.write(Self::TYPE);
-2504        buf.write(self.seq_no);
-2505    }
-2506}
-2507
-2508/// Helper struct for display implementations.
-2509// NOTE: Due to lifetimes in fmt::Arguments it's not possible to make this a simple function that
-2510// avoids allocations.
-2511struct DisplayOption<T: Display> {
-2512    field_name: &'static str,
-2513    op: Option<T>,
-2514}
-2515
-2516impl<T: Display> DisplayOption<T> {
-2517    fn new(field_name: &'static str, op: Option<T>) -> Self {
-2518        Self { field_name, op }
-2519    }
-2520}
-2521
-2522impl<T: Display> Display for DisplayOption<T> {
-2523    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-2524        if let Some(x) = self.op.as_ref() {
-2525            write!(f, "{}: {x}", self.field_name)
-2526        } else {
-2527            fmt::Result::Ok(())
-2528        }
-2529    }
-2530}
+2466    /// Compute the number of bytes needed to encode the frame
+2467    pub(crate) const fn size(&self) -> usize {
+2468        let type_size = Self::TYPE.size();
+2469        let seq_no_bytes = self.seq_no.size();
+2470        type_size + seq_no_bytes
+2471    }
+2472
+2473    /// Read the frame contents from the buffer
+2474    ///
+2475    /// Should only be called when the frame type has been identified as
+2476    /// [`FrameType::RemoveAddress`].
+2477    pub(crate) fn read<R: Buf>(bytes: &mut R) -> coding::Result<Self> {
+2478        Ok(Self {
+2479            seq_no: bytes.get()?,
+2480        })
+2481    }
+2482
+2483    const fn get_type(&self) -> FrameType {
+2484        FrameType::RemoveAddress
+2485    }
+2486}
+2487
+2488impl Encodable for RemoveAddress {
+2489    fn encode<W: BufMut>(&self, buf: &mut W) {
+2490        buf.write(Self::TYPE);
+2491        buf.write(self.seq_no);
+2492    }
+2493}
+2494
+2495/// Helper struct for display implementations.
+2496// NOTE: Due to lifetimes in fmt::Arguments it's not possible to make this a simple function that
+2497// avoids allocations.
+2498struct DisplayOption<T: Display> {
+2499    field_name: &'static str,
+2500    op: Option<T>,
+2501}
+2502
+2503impl<T: Display> DisplayOption<T> {
+2504    fn new(field_name: &'static str, op: Option<T>) -> Self {
+2505        Self { field_name, op }
+2506    }
+2507}
+2508
+2509impl<T: Display> Display for DisplayOption<T> {
+2510    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+2511        if let Some(x) = self.op.as_ref() {
+2512            write!(f, "{}: {x}", self.field_name)
+2513        } else {
+2514            fmt::Result::Ok(())
+2515        }
+2516    }
+2517}
+2518
+2519#[cfg(test)]
+2520mod test {
+2521    use super::*;
+2522    use crate::coding::Encodable;
+2523    use assert_matches::assert_matches;
+2524
+2525    #[test]
+2526    fn frame_type() {
+2527        assert_eq!(
+2528            FrameType::try_from(FrameType::Padding.to_u64()),
+2529            Ok(FrameType::Padding),
+2530        );
 2531
-2532#[cfg(test)]
-2533mod test {
-2534    use super::*;
-2535    use crate::coding::Encodable;
-2536    use assert_matches::assert_matches;
-2537
-2538    #[test]
-2539    fn frame_type() {
-2540        assert_eq!(
-2541            FrameType::try_from(FrameType::Padding.to_u64()),
-2542            Ok(FrameType::Padding),
-2543        );
-2544
-2545        assert_eq!(
-2546            FrameType::try_from(FrameType::Datagram(DatagramInfo(0x30)).to_u64()),
-2547            Ok(FrameType::Datagram(DatagramInfo(0x30))),
-2548        );
-2549
-2550        assert_eq!(
-2551            FrameType::try_from(FrameType::Stream(StreamInfo(0x08)).to_u64()),
-2552            Ok(FrameType::Stream(StreamInfo(0x08))),
-2553        );
-2554    }
-2555
-2556    #[track_caller]
-2557    fn frames(buf: Vec<u8>) -> Vec<Frame> {
-2558        Iter::new(Bytes::from(buf))
-2559            .unwrap()
-2560            .collect::<Result<Vec<_>, _>>()
-2561            .unwrap()
-2562    }
-2563
-2564    #[test]
-2565    fn ack_coding() {
-2566        const PACKETS: &[u64] = &[1, 2, 3, 5, 10, 11, 14];
-2567        let mut ranges = ArrayRangeSet::new();
-2568        for &packet in PACKETS {
-2569            ranges.insert(packet..packet + 1);
-2570        }
-2571        let mut buf = Vec::new();
-2572        const ECN: EcnCounts = EcnCounts {
-2573            ect0: 42,
-2574            ect1: 24,
-2575            ce: 12,
-2576        };
-2577        Ack::encoder(42, &ranges, Some(&ECN)).encode(&mut buf);
-2578        let frames = frames(buf);
-2579        assert_eq!(frames.len(), 1);
-2580        match frames[0] {
-2581            Frame::Ack(ref ack) => {
-2582                let mut packets = ack.iter().flatten().collect::<Vec<_>>();
-2583                packets.sort_unstable();
-2584                assert_eq!(&packets[..], PACKETS);
-2585                assert_eq!(ack.ecn, Some(ECN));
-2586            }
-2587            ref x => panic!("incorrect frame {x:?}"),
-2588        }
-2589    }
-2590
-2591    #[test]
-2592    #[allow(clippy::range_plus_one)]
-2593    fn path_ack_coding_with_ecn() {
-2594        const PACKETS: &[u64] = &[1, 2, 3, 5, 10, 11, 14];
-2595        let mut ranges = ArrayRangeSet::new();
-2596        for &packet in PACKETS {
-2597            ranges.insert(packet..packet + 1);
-2598        }
-2599        let mut buf = Vec::new();
-2600        const ECN: EcnCounts = EcnCounts {
-2601            ect0: 42,
-2602            ect1: 24,
-2603            ce: 12,
-2604        };
-2605        const PATH_ID: PathId = PathId::MAX;
-2606        PathAck::encoder(PATH_ID, 42, &ranges, Some(&ECN)).encode(&mut buf);
-2607        let frames = frames(buf);
-2608        assert_eq!(frames.len(), 1);
-2609        match frames[0] {
-2610            Frame::PathAck(ref ack) => {
-2611                assert_eq!(ack.path_id, PATH_ID);
-2612                let mut packets = ack.ranges.iter().flatten().collect::<Vec<_>>();
-2613                packets.sort_unstable();
-2614                assert_eq!(&packets[..], PACKETS);
-2615                assert_eq!(ack.ecn, Some(ECN));
-2616            }
-2617            ref x => panic!("incorrect frame {x:?}"),
-2618        }
-2619    }
-2620
-2621    #[test]
-2622    #[allow(clippy::range_plus_one)]
-2623    fn path_ack_coding_no_ecn() {
-2624        const PACKETS: &[u64] = &[1, 2, 3, 5, 10, 11, 14];
-2625        let mut ranges = ArrayRangeSet::new();
-2626        for &packet in PACKETS {
-2627            ranges.insert(packet..packet + 1);
-2628        }
-2629        let mut buf = Vec::new();
-2630        const PATH_ID: PathId = PathId::MAX;
-2631        PathAck::encoder(PATH_ID, 42, &ranges, None).encode(&mut buf);
-2632        let frames = frames(buf);
-2633        assert_eq!(frames.len(), 1);
-2634        match frames[0] {
-2635            Frame::PathAck(ref ack) => {
-2636                assert_eq!(ack.path_id, PATH_ID);
-2637                let mut packets = ack.ranges.iter().flatten().collect::<Vec<_>>();
-2638                packets.sort_unstable();
-2639                assert_eq!(&packets[..], PACKETS);
-2640                assert_eq!(ack.ecn, None);
-2641            }
-2642            ref x => panic!("incorrect frame {x:?}"),
-2643        }
-2644    }
-2645
-2646    #[test]
-2647    fn ack_frequency_coding() {
-2648        let mut buf = Vec::new();
-2649        let original = AckFrequency {
-2650            sequence: VarInt(42),
-2651            ack_eliciting_threshold: VarInt(20),
-2652            request_max_ack_delay: VarInt(50_000),
-2653            reordering_threshold: VarInt(1),
-2654        };
-2655        original.encode(&mut buf);
-2656        let frames = frames(buf);
-2657        assert_eq!(frames.len(), 1);
-2658        match &frames[0] {
-2659            Frame::AckFrequency(decoded) => assert_eq!(decoded, &original),
-2660            x => panic!("incorrect frame {x:?}"),
-2661        }
-2662    }
-2663
-2664    #[test]
-2665    fn immediate_ack_coding() {
-2666        let mut buf = Vec::new();
-2667        FrameType::ImmediateAck.encode(&mut buf);
-2668        let frames = frames(buf);
-2669        assert_eq!(frames.len(), 1);
-2670        assert_matches!(&frames[0], Frame::ImmediateAck);
-2671    }
-2672
-2673    /// Test that encoding and decoding [`ObservedAddr`] produces the same result.
-2674    #[test]
-2675    fn test_observed_addr_roundrip() {
-2676        let observed_addr = ObservedAddr {
-2677            seq_no: VarInt(42),
-2678            ip: std::net::Ipv4Addr::LOCALHOST.into(),
-2679            port: 4242,
-2680        };
-2681        let mut buf = Vec::with_capacity(observed_addr.size());
-2682        observed_addr.encode(&mut buf);
-2683
-2684        assert_eq!(
-2685            observed_addr.size(),
-2686            buf.len(),
-2687            "expected written bytes and actual size differ"
-2688        );
-2689
-2690        let mut decoded = frames(buf);
-2691        assert_eq!(decoded.len(), 1);
-2692        match decoded.pop().expect("non empty") {
-2693            Frame::ObservedAddr(decoded) => assert_eq!(decoded, observed_addr),
-2694            x => panic!("incorrect frame {x:?}"),
-2695        }
-2696    }
-2697
-2698    #[test]
-2699    fn test_path_abandon_roundtrip() {
-2700        let abandon = PathAbandon {
-2701            path_id: PathId(42),
-2702            error_code: TransportErrorCode::NO_ERROR,
-2703        };
-2704        let mut buf = Vec::new();
-2705        abandon.encode(&mut buf);
-2706
-2707        let mut decoded = frames(buf);
-2708        assert_eq!(decoded.len(), 1);
-2709        match decoded.pop().expect("non empty") {
-2710            Frame::PathAbandon(decoded) => assert_eq!(decoded, abandon),
-2711            x => panic!("incorrect frame {x:?}"),
-2712        }
-2713    }
-2714
-2715    #[test]
-2716    fn test_path_status_available_roundtrip() {
-2717        let path_status_available = PathStatusAvailable {
-2718            path_id: PathId(42),
-2719            status_seq_no: VarInt(73),
-2720        };
-2721        let mut buf = Vec::new();
-2722        path_status_available.encode(&mut buf);
-2723
-2724        let mut decoded = frames(buf);
-2725        assert_eq!(decoded.len(), 1);
-2726        match decoded.pop().expect("non empty") {
-2727            Frame::PathStatusAvailable(decoded) => assert_eq!(decoded, path_status_available),
-2728            x => panic!("incorrect frame {x:?}"),
-2729        }
-2730    }
-2731
-2732    #[test]
-2733    fn test_path_status_backup_roundtrip() {
-2734        let path_status_backup = PathStatusBackup {
-2735            path_id: PathId(42),
-2736            status_seq_no: VarInt(73),
-2737        };
-2738        let mut buf = Vec::new();
-2739        path_status_backup.encode(&mut buf);
-2740
-2741        let mut decoded = frames(buf);
-2742        assert_eq!(decoded.len(), 1);
-2743        match decoded.pop().expect("non empty") {
-2744            Frame::PathStatusBackup(decoded) => assert_eq!(decoded, path_status_backup),
-2745            x => panic!("incorrect frame {x:?}"),
-2746        }
-2747    }
-2748
-2749    #[test]
-2750    fn test_path_new_connection_id_roundtrip() {
-2751        let cid = NewConnectionId {
-2752            path_id: Some(PathId(22)),
-2753            sequence: 31,
-2754            retire_prior_to: 13,
-2755            id: ConnectionId::new(&[0xAB; 8]),
-2756            reset_token: ResetToken::from([0xCD; crate::RESET_TOKEN_SIZE]),
-2757        };
-2758        let mut buf = Vec::new();
-2759        cid.encode(&mut buf);
-2760
-2761        let mut decoded = frames(buf);
-2762        assert_eq!(decoded.len(), 1);
-2763        match decoded.pop().expect("non empty") {
-2764            Frame::NewConnectionId(decoded) => assert_eq!(decoded, cid),
-2765            x => panic!("incorrect frame {x:?}"),
-2766        }
-2767    }
-2768
-2769    #[test]
-2770    fn test_path_retire_connection_id_roundtrip() {
-2771        let retire_cid = RetireConnectionId {
-2772            path_id: Some(PathId(22)),
-2773            sequence: 31,
-2774        };
+2532        assert_eq!(
+2533            FrameType::try_from(FrameType::Datagram(DatagramInfo(0x30)).to_u64()),
+2534            Ok(FrameType::Datagram(DatagramInfo(0x30))),
+2535        );
+2536
+2537        assert_eq!(
+2538            FrameType::try_from(FrameType::Stream(StreamInfo(0x08)).to_u64()),
+2539            Ok(FrameType::Stream(StreamInfo(0x08))),
+2540        );
+2541    }
+2542
+2543    #[track_caller]
+2544    fn frames(buf: Vec<u8>) -> Vec<Frame> {
+2545        Iter::new(Bytes::from(buf))
+2546            .unwrap()
+2547            .collect::<Result<Vec<_>, _>>()
+2548            .unwrap()
+2549    }
+2550
+2551    #[test]
+2552    fn ack_coding() {
+2553        const PACKETS: &[u64] = &[1, 2, 3, 5, 10, 11, 14];
+2554        let mut ranges = ArrayRangeSet::new();
+2555        for &packet in PACKETS {
+2556            ranges.insert(packet..packet + 1);
+2557        }
+2558        let mut buf = Vec::new();
+2559        const ECN: EcnCounts = EcnCounts {
+2560            ect0: 42,
+2561            ect1: 24,
+2562            ce: 12,
+2563        };
+2564        Ack::encoder(42, &ranges, Some(&ECN)).encode(&mut buf);
+2565        let frames = frames(buf);
+2566        assert_eq!(frames.len(), 1);
+2567        match frames[0] {
+2568            Frame::Ack(ref ack) => {
+2569                let mut packets = ack.iter().flatten().collect::<Vec<_>>();
+2570                packets.sort_unstable();
+2571                assert_eq!(&packets[..], PACKETS);
+2572                assert_eq!(ack.ecn, Some(ECN));
+2573            }
+2574            ref x => panic!("incorrect frame {x:?}"),
+2575        }
+2576    }
+2577
+2578    #[test]
+2579    #[allow(clippy::range_plus_one)]
+2580    fn path_ack_coding_with_ecn() {
+2581        const PACKETS: &[u64] = &[1, 2, 3, 5, 10, 11, 14];
+2582        let mut ranges = ArrayRangeSet::new();
+2583        for &packet in PACKETS {
+2584            ranges.insert(packet..packet + 1);
+2585        }
+2586        let mut buf = Vec::new();
+2587        const ECN: EcnCounts = EcnCounts {
+2588            ect0: 42,
+2589            ect1: 24,
+2590            ce: 12,
+2591        };
+2592        const PATH_ID: PathId = PathId::MAX;
+2593        PathAck::encoder(PATH_ID, 42, &ranges, Some(&ECN)).encode(&mut buf);
+2594        let frames = frames(buf);
+2595        assert_eq!(frames.len(), 1);
+2596        match frames[0] {
+2597            Frame::PathAck(ref ack) => {
+2598                assert_eq!(ack.path_id, PATH_ID);
+2599                let mut packets = ack.ranges.iter().flatten().collect::<Vec<_>>();
+2600                packets.sort_unstable();
+2601                assert_eq!(&packets[..], PACKETS);
+2602                assert_eq!(ack.ecn, Some(ECN));
+2603            }
+2604            ref x => panic!("incorrect frame {x:?}"),
+2605        }
+2606    }
+2607
+2608    #[test]
+2609    #[allow(clippy::range_plus_one)]
+2610    fn path_ack_coding_no_ecn() {
+2611        const PACKETS: &[u64] = &[1, 2, 3, 5, 10, 11, 14];
+2612        let mut ranges = ArrayRangeSet::new();
+2613        for &packet in PACKETS {
+2614            ranges.insert(packet..packet + 1);
+2615        }
+2616        let mut buf = Vec::new();
+2617        const PATH_ID: PathId = PathId::MAX;
+2618        PathAck::encoder(PATH_ID, 42, &ranges, None).encode(&mut buf);
+2619        let frames = frames(buf);
+2620        assert_eq!(frames.len(), 1);
+2621        match frames[0] {
+2622            Frame::PathAck(ref ack) => {
+2623                assert_eq!(ack.path_id, PATH_ID);
+2624                let mut packets = ack.ranges.iter().flatten().collect::<Vec<_>>();
+2625                packets.sort_unstable();
+2626                assert_eq!(&packets[..], PACKETS);
+2627                assert_eq!(ack.ecn, None);
+2628            }
+2629            ref x => panic!("incorrect frame {x:?}"),
+2630        }
+2631    }
+2632
+2633    #[test]
+2634    fn ack_frequency_coding() {
+2635        let mut buf = Vec::new();
+2636        let original = AckFrequency {
+2637            sequence: VarInt(42),
+2638            ack_eliciting_threshold: VarInt(20),
+2639            request_max_ack_delay: VarInt(50_000),
+2640            reordering_threshold: VarInt(1),
+2641        };
+2642        original.encode(&mut buf);
+2643        let frames = frames(buf);
+2644        assert_eq!(frames.len(), 1);
+2645        match &frames[0] {
+2646            Frame::AckFrequency(decoded) => assert_eq!(decoded, &original),
+2647            x => panic!("incorrect frame {x:?}"),
+2648        }
+2649    }
+2650
+2651    #[test]
+2652    fn immediate_ack_coding() {
+2653        let mut buf = Vec::new();
+2654        FrameType::ImmediateAck.encode(&mut buf);
+2655        let frames = frames(buf);
+2656        assert_eq!(frames.len(), 1);
+2657        assert_matches!(&frames[0], Frame::ImmediateAck);
+2658    }
+2659
+2660    /// Test that encoding and decoding [`ObservedAddr`] produces the same result.
+2661    #[test]
+2662    fn test_observed_addr_roundrip() {
+2663        let observed_addr = ObservedAddr {
+2664            seq_no: VarInt(42),
+2665            ip: std::net::Ipv4Addr::LOCALHOST.into(),
+2666            port: 4242,
+2667        };
+2668        let mut buf = Vec::with_capacity(observed_addr.size());
+2669        observed_addr.encode(&mut buf);
+2670
+2671        assert_eq!(
+2672            observed_addr.size(),
+2673            buf.len(),
+2674            "expected written bytes and actual size differ"
+2675        );
+2676
+2677        let mut decoded = frames(buf);
+2678        assert_eq!(decoded.len(), 1);
+2679        match decoded.pop().expect("non empty") {
+2680            Frame::ObservedAddr(decoded) => assert_eq!(decoded, observed_addr),
+2681            x => panic!("incorrect frame {x:?}"),
+2682        }
+2683    }
+2684
+2685    #[test]
+2686    fn test_path_abandon_roundtrip() {
+2687        let abandon = PathAbandon {
+2688            path_id: PathId(42),
+2689            error_code: TransportErrorCode::NO_ERROR,
+2690        };
+2691        let mut buf = Vec::new();
+2692        abandon.encode(&mut buf);
+2693
+2694        let mut decoded = frames(buf);
+2695        assert_eq!(decoded.len(), 1);
+2696        match decoded.pop().expect("non empty") {
+2697            Frame::PathAbandon(decoded) => assert_eq!(decoded, abandon),
+2698            x => panic!("incorrect frame {x:?}"),
+2699        }
+2700    }
+2701
+2702    #[test]
+2703    fn test_path_status_available_roundtrip() {
+2704        let path_status_available = PathStatusAvailable {
+2705            path_id: PathId(42),
+2706            status_seq_no: VarInt(73),
+2707        };
+2708        let mut buf = Vec::new();
+2709        path_status_available.encode(&mut buf);
+2710
+2711        let mut decoded = frames(buf);
+2712        assert_eq!(decoded.len(), 1);
+2713        match decoded.pop().expect("non empty") {
+2714            Frame::PathStatusAvailable(decoded) => assert_eq!(decoded, path_status_available),
+2715            x => panic!("incorrect frame {x:?}"),
+2716        }
+2717    }
+2718
+2719    #[test]
+2720    fn test_path_status_backup_roundtrip() {
+2721        let path_status_backup = PathStatusBackup {
+2722            path_id: PathId(42),
+2723            status_seq_no: VarInt(73),
+2724        };
+2725        let mut buf = Vec::new();
+2726        path_status_backup.encode(&mut buf);
+2727
+2728        let mut decoded = frames(buf);
+2729        assert_eq!(decoded.len(), 1);
+2730        match decoded.pop().expect("non empty") {
+2731            Frame::PathStatusBackup(decoded) => assert_eq!(decoded, path_status_backup),
+2732            x => panic!("incorrect frame {x:?}"),
+2733        }
+2734    }
+2735
+2736    #[test]
+2737    fn test_path_new_connection_id_roundtrip() {
+2738        let cid = NewConnectionId {
+2739            path_id: Some(PathId(22)),
+2740            sequence: 31,
+2741            retire_prior_to: 13,
+2742            id: ConnectionId::new(&[0xAB; 8]),
+2743            reset_token: ResetToken::from([0xCD; crate::RESET_TOKEN_SIZE]),
+2744        };
+2745        let mut buf = Vec::new();
+2746        cid.encode(&mut buf);
+2747
+2748        let mut decoded = frames(buf);
+2749        assert_eq!(decoded.len(), 1);
+2750        match decoded.pop().expect("non empty") {
+2751            Frame::NewConnectionId(decoded) => assert_eq!(decoded, cid),
+2752            x => panic!("incorrect frame {x:?}"),
+2753        }
+2754    }
+2755
+2756    #[test]
+2757    fn test_path_retire_connection_id_roundtrip() {
+2758        let retire_cid = RetireConnectionId {
+2759            path_id: Some(PathId(22)),
+2760            sequence: 31,
+2761        };
+2762        let mut buf = Vec::new();
+2763        retire_cid.encode(&mut buf);
+2764
+2765        let mut decoded = frames(buf);
+2766        assert_eq!(decoded.len(), 1);
+2767        match decoded.pop().expect("non empty") {
+2768            Frame::RetireConnectionId(decoded) => assert_eq!(decoded, retire_cid),
+2769            x => panic!("incorrect frame {x:?}"),
+2770        }
+2771    }
+2772
+2773    #[test]
+2774    fn test_paths_blocked_path_cids_blocked_roundtrip() {
 2775        let mut buf = Vec::new();
-2776        retire_cid.encode(&mut buf);
-2777
-2778        let mut decoded = frames(buf);
-2779        assert_eq!(decoded.len(), 1);
-2780        match decoded.pop().expect("non empty") {
-2781            Frame::RetireConnectionId(decoded) => assert_eq!(decoded, retire_cid),
-2782            x => panic!("incorrect frame {x:?}"),
-2783        }
-2784    }
-2785
-2786    #[test]
-2787    fn test_paths_blocked_path_cids_blocked_roundtrip() {
-2788        let mut buf = Vec::new();
-2789
-2790        let frame0 = PathsBlocked(PathId(22));
-2791        frame0.encode(&mut buf);
-2792        let frame1 = PathCidsBlocked {
-2793            path_id: PathId(23),
-2794            next_seq: VarInt(32),
-2795        };
-2796        frame1.encode(&mut buf);
-2797
-2798        let mut decoded = frames(buf);
-2799        assert_eq!(decoded.len(), 2);
-2800        match decoded.pop().expect("non empty") {
-2801            Frame::PathCidsBlocked(decoded) => assert_eq!(decoded, frame1),
-2802            x => panic!("incorrect frame {x:?}"),
-2803        }
-2804        match decoded.pop().expect("non empty") {
-2805            Frame::PathsBlocked(decoded) => assert_eq!(decoded, frame0),
-2806            x => panic!("incorrect frame {x:?}"),
-2807        }
-2808    }
-2809
-2810    /// Test that encoding and decoding [`AddAddress`] produces the same result
-2811    #[test]
-2812    fn test_add_address_roundrip() {
-2813        let add_address = AddAddress {
-2814            seq_no: VarInt(42),
-2815            ip: std::net::Ipv4Addr::LOCALHOST.into(),
-2816            port: 4242,
-2817        };
-2818        let mut buf = Vec::with_capacity(add_address.size());
-2819        add_address.encode(&mut buf);
-2820
-2821        assert_eq!(
-2822            add_address.size(),
-2823            buf.len(),
-2824            "expected written bytes and actual size differ"
-2825        );
-2826
-2827        let mut decoded = frames(buf);
-2828        assert_eq!(decoded.len(), 1);
-2829        match decoded.pop().expect("non empty") {
-2830            Frame::AddAddress(decoded) => assert_eq!(decoded, add_address),
-2831            x => panic!("incorrect frame {x:?}"),
-2832        }
-2833    }
-2834
-2835    /// Test that encoding and decoding [`AddAddress`] produces the same result
-2836    #[test]
-2837    fn test_reach_out_roundrip() {
-2838        let reach_out = ReachOut {
-2839            round: VarInt(42),
-2840            ip: std::net::Ipv6Addr::LOCALHOST.into(),
-2841            port: 4242,
-2842        };
-2843        let mut buf = Vec::with_capacity(reach_out.size());
-2844        reach_out.encode(&mut buf);
-2845
-2846        assert_eq!(
-2847            reach_out.size(),
-2848            buf.len(),
-2849            "expected written bytes and actual size differ"
-2850        );
-2851
-2852        let mut decoded = frames(buf);
-2853        assert_eq!(decoded.len(), 1);
-2854        match decoded.pop().expect("non empty") {
-2855            Frame::ReachOut(decoded) => assert_eq!(decoded, reach_out),
-2856            x => panic!("incorrect frame {x:?}"),
-2857        }
-2858    }
+2776
+2777        let frame0 = PathsBlocked(PathId(22));
+2778        frame0.encode(&mut buf);
+2779        let frame1 = PathCidsBlocked {
+2780            path_id: PathId(23),
+2781            next_seq: VarInt(32),
+2782        };
+2783        frame1.encode(&mut buf);
+2784
+2785        let mut decoded = frames(buf);
+2786        assert_eq!(decoded.len(), 2);
+2787        match decoded.pop().expect("non empty") {
+2788            Frame::PathCidsBlocked(decoded) => assert_eq!(decoded, frame1),
+2789            x => panic!("incorrect frame {x:?}"),
+2790        }
+2791        match decoded.pop().expect("non empty") {
+2792            Frame::PathsBlocked(decoded) => assert_eq!(decoded, frame0),
+2793            x => panic!("incorrect frame {x:?}"),
+2794        }
+2795    }
+2796
+2797    /// Test that encoding and decoding [`AddAddress`] produces the same result
+2798    #[test]
+2799    fn test_add_address_roundrip() {
+2800        let add_address = AddAddress {
+2801            seq_no: VarInt(42),
+2802            ip: std::net::Ipv4Addr::LOCALHOST.into(),
+2803            port: 4242,
+2804        };
+2805        let mut buf = Vec::with_capacity(add_address.size());
+2806        add_address.encode(&mut buf);
+2807
+2808        assert_eq!(
+2809            add_address.size(),
+2810            buf.len(),
+2811            "expected written bytes and actual size differ"
+2812        );
+2813
+2814        let mut decoded = frames(buf);
+2815        assert_eq!(decoded.len(), 1);
+2816        match decoded.pop().expect("non empty") {
+2817            Frame::AddAddress(decoded) => assert_eq!(decoded, add_address),
+2818            x => panic!("incorrect frame {x:?}"),
+2819        }
+2820    }
+2821
+2822    /// Test that encoding and decoding [`AddAddress`] produces the same result
+2823    #[test]
+2824    fn test_reach_out_roundrip() {
+2825        let reach_out = ReachOut {
+2826            round: VarInt(42),
+2827            ip: std::net::Ipv6Addr::LOCALHOST.into(),
+2828            port: 4242,
+2829        };
+2830        let mut buf = Vec::with_capacity(reach_out.size());
+2831        reach_out.encode(&mut buf);
+2832
+2833        assert_eq!(
+2834            reach_out.size(),
+2835            buf.len(),
+2836            "expected written bytes and actual size differ"
+2837        );
+2838
+2839        let mut decoded = frames(buf);
+2840        assert_eq!(decoded.len(), 1);
+2841        match decoded.pop().expect("non empty") {
+2842            Frame::ReachOut(decoded) => assert_eq!(decoded, reach_out),
+2843            x => panic!("incorrect frame {x:?}"),
+2844        }
+2845    }
+2846
+2847    /// Test that encoding and decoding [`RemoveAddress`] produces the same result
+2848    #[test]
+2849    fn test_remove_address_roundrip() {
+2850        let remove_addr = RemoveAddress::new(VarInt(10));
+2851        let mut buf = Vec::with_capacity(remove_addr.size());
+2852        remove_addr.encode(&mut buf);
+2853
+2854        assert_eq!(
+2855            remove_addr.size(),
+2856            buf.len(),
+2857            "expected written bytes and actual size differ"
+2858        );
 2859
-2860    /// Test that encoding and decoding [`RemoveAddress`] produces the same result
-2861    #[test]
-2862    fn test_remove_address_roundrip() {
-2863        let remove_addr = RemoveAddress::new(VarInt(10));
-2864        let mut buf = Vec::with_capacity(remove_addr.size());
-2865        remove_addr.encode(&mut buf);
-2866
-2867        assert_eq!(
-2868            remove_addr.size(),
-2869            buf.len(),
-2870            "expected written bytes and actual size differ"
-2871        );
-2872
-2873        let mut decoded = frames(buf);
-2874        assert_eq!(decoded.len(), 1);
-2875        match decoded.pop().expect("non empty") {
-2876            Frame::RemoveAddress(decoded) => assert_eq!(decoded, remove_addr),
-2877            x => panic!("incorrect frame {x:?}"),
-2878        }
-2879    }
-2880}

\ No newline at end of file +2860 let mut decoded = frames(buf); +2861 assert_eq!(decoded.len(), 1); +2862 match decoded.pop().expect("non empty") { +2863 Frame::RemoveAddress(decoded) => assert_eq!(decoded, remove_addr), +2864 x => panic!("incorrect frame {x:?}"), +2865 } +2866 } +2867} \ No newline at end of file diff --git a/pr/616/docs/src/noq_proto/n0_nat_traversal.rs.html b/pr/616/docs/src/noq_proto/n0_nat_traversal.rs.html index 6d8bc22fd..37b1e10c4 100644 --- a/pr/616/docs/src/noq_proto/n0_nat_traversal.rs.html +++ b/pr/616/docs/src/noq_proto/n0_nat_traversal.rs.html @@ -9,690 +9,831 @@ 9use tracing::{debug, trace}; 10 11use crate::{ -12 FourTuple, PathId, Side, VarInt, -13 frame::{AddAddress, ReachOut, RemoveAddress}, -14}; -15 -16type IpPort = (IpAddr, u16); -17 -18/// Errors that the nat traversal state might encounter. -19#[derive(Debug, thiserror::Error)] -20pub enum Error { -21 /// An endpoint (local or remote) tried to add too many addresses to their advertised set -22 #[error("Tried to add too many addresses to their advertised set")] -23 TooManyAddresses, -24 /// The operation is not allowed for this endpoint's connection side -25 #[error("Not allowed for this endpoint's connection side")] -26 WrongConnectionSide, -27 /// The extension was not negotiated -28 #[error("n0's nat traversal was not negotiated")] -29 ExtensionNotNegotiated, -30 /// Not enough addresses to complete the operation -31 #[error("Not enough addresses")] -32 NotEnoughAddresses, -33 /// Nat traversal attempt failed due to a multipath error -34 #[error("Failed to establish paths {0}")] -35 Multipath(super::PathError), -36 /// Attempted to initiate NAT traversal on a closed, or closing connection. -37 #[error("The connection is already closed")] -38 Closed, -39} -40 -41pub(crate) struct NatTraversalRound { -42 /// Sequence number to use for the new reach out frames. -43 pub(crate) new_round: VarInt, -44 /// Addresses to use to send reach out frames. -45 pub(crate) reach_out_at: FxHashSet<IpPort>, -46 /// Remotes to probe by attempting to open new paths. -47 /// -48 /// The addresses include their Id, so that it can be used to signal these should be returned -49 /// in a nat traversal continuation by calling [`ClientState::report_in_continuation`]. -50 /// -51 /// These are filtered and mapped to the IP family the local socket supports. -52 pub(crate) addresses_to_probe: Vec<(VarInt, IpPort)>, -53 /// [`PathId`]s of the cancelled round. -54 pub(crate) prev_round_path_ids: Vec<PathId>, -55} -56 -57/// Event emitted when the client receives ADD_ADDRESS or REMOVE_ADDRESS frames. -58#[derive(Debug, Clone)] -59pub enum Event { -60 /// An ADD_ADDRESS frame was received. -61 AddressAdded(SocketAddr), -62 /// A REMOVE_ADDRESS frame was received. -63 AddressRemoved(SocketAddr), -64} -65 -66/// State kept for n0's nat traversal -67#[derive(Debug, Default)] -68pub(crate) enum State { -69 #[default] -70 NotNegotiated, -71 ClientSide(ClientState), -72 ServerSide(ServerState), -73} -74 -75impl State { -76 pub(crate) fn new(max_remote_addresses: u8, max_local_addresses: u8, side: Side) -> Self { -77 match side { -78 Side::Client => Self::ClientSide(ClientState::new( -79 max_remote_addresses.into(), -80 max_local_addresses.into(), -81 )), -82 Side::Server => Self::ServerSide(ServerState::new( -83 max_remote_addresses.into(), -84 max_local_addresses.into(), -85 )), +12 FourTuple, Side, VarInt, +13 connection::spaces::PendingReachOutFrames, +14 frame::{AddAddress, ReachOut, RemoveAddress}, +15}; +16 +17type IpPort = (IpAddr, u16); +18 +19/// Errors that the nat traversal state might encounter. +20#[derive(Debug, thiserror::Error)] +21pub enum Error { +22 /// An endpoint (local or remote) tried to add too many addresses to their advertised set +23 #[error("Tried to add too many addresses to their advertised set")] +24 TooManyAddresses, +25 /// The operation is not allowed for this endpoint's connection side +26 #[error("Not allowed for this endpoint's connection side")] +27 WrongConnectionSide, +28 /// The extension was not negotiated +29 #[error("n0's nat traversal was not negotiated")] +30 ExtensionNotNegotiated, +31 /// Not enough addresses to complete the operation +32 #[error("Not enough addresses")] +33 NotEnoughAddresses, +34 /// Nat traversal attempt failed due to a multipath error +35 #[error("Failed to establish paths {0}")] +36 Multipath(super::PathError), +37 /// Attempted to initiate NAT traversal on a closed, or closing connection. +38 #[error("The connection is already closed")] +39 Closed, +40} +41 +42/// Event emitted when the client receives ADD_ADDRESS or REMOVE_ADDRESS frames. +43#[derive(Debug, Clone)] +44pub enum Event { +45 /// An ADD_ADDRESS frame was received. +46 AddressAdded(SocketAddr), +47 /// A REMOVE_ADDRESS frame was received. +48 AddressRemoved(SocketAddr), +49} +50 +51/// State kept for n0's nat traversal +52#[derive(Debug, Default)] +53pub(crate) enum State { +54 #[default] +55 NotNegotiated, +56 ClientSide(ClientState), +57 ServerSide(ServerState), +58} +59 +60impl State { +61 pub(crate) fn new(max_remote_addresses: u8, max_local_addresses: u8, side: Side) -> Self { +62 match side { +63 Side::Client => Self::ClientSide(ClientState::new( +64 max_remote_addresses.into(), +65 max_local_addresses.into(), +66 )), +67 Side::Server => Self::ServerSide(ServerState::new( +68 max_remote_addresses.into(), +69 max_local_addresses.into(), +70 )), +71 } +72 } +73 +74 pub(crate) fn is_negotiated(&self) -> bool { +75 match self { +76 Self::NotNegotiated => false, +77 Self::ClientSide(_) | Self::ServerSide(_) => true, +78 } +79 } +80 +81 pub(crate) fn client_side(&self) -> Result<&ClientState, Error> { +82 match self { +83 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), +84 Self::ClientSide(client_side) => Ok(client_side), +85 Self::ServerSide(_) => Err(Error::WrongConnectionSide), 86 } 87 } 88 -89 pub(crate) fn is_negotiated(&self) -> bool { +89 pub(crate) fn client_side_mut(&mut self) -> Result<&mut ClientState, Error> { 90 match self { -91 Self::NotNegotiated => false, -92 Self::ClientSide(_) | Self::ServerSide(_) => true, -93 } -94 } -95 -96 pub(crate) fn client_side(&self) -> Result<&ClientState, Error> { -97 match self { -98 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), -99 Self::ClientSide(client_side) => Ok(client_side), -100 Self::ServerSide(_) => Err(Error::WrongConnectionSide), -101 } -102 } -103 -104 pub(crate) fn client_side_mut(&mut self) -> Result<&mut ClientState, Error> { -105 match self { -106 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), -107 Self::ClientSide(client_side) => Ok(client_side), -108 Self::ServerSide(_) => Err(Error::WrongConnectionSide), -109 } -110 } -111 -112 pub(crate) fn server_side_mut(&mut self) -> Result<&mut ServerState, Error> { -113 match self { -114 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), -115 Self::ClientSide(_) => Err(Error::WrongConnectionSide), -116 Self::ServerSide(server_side) => Ok(server_side), -117 } -118 } -119 -120 /// Adds a local address to use for nat traversal. -121 /// -122 /// When this endpoint is the server within the connection, these addresses will be sent to the -123 /// client in add address frames. For clients, these addresses will be sent in reach out frames -124 /// when nat traversal attempts are initiated. -125 /// -126 /// If a frame should be sent, it is returned. -127 pub(crate) fn add_local_address( -128 &mut self, -129 address: SocketAddr, -130 ) -> Result<Option<AddAddress>, Error> { -131 let ip_port = IpPort::from((address.ip(), address.port())); -132 match self { -133 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), -134 Self::ClientSide(client_state) => { -135 client_state.add_local_address(ip_port)?; -136 Ok(None) -137 } -138 Self::ServerSide(server_state) => server_state.add_local_address(ip_port), -139 } -140 } -141 -142 /// Removes a local address from the advertised set for nat traversal. -143 /// -144 /// When this endpoint is the server, removed addresses must be reported with remove address -145 /// frames. Clients will simply stop reporting these addresses in reach out frames. -146 /// -147 /// If a frame should be sent, it is returned. -148 pub(crate) fn remove_local_address( -149 &mut self, -150 address: SocketAddr, -151 ) -> Result<Option<RemoveAddress>, Error> { -152 let address = IpPort::from((address.ip(), address.port())); -153 match self { -154 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), -155 Self::ClientSide(client_state) => { -156 client_state.remove_local_address(&address); -157 Ok(None) -158 } -159 Self::ServerSide(server_state) => Ok(server_state.remove_local_address(&address)), -160 } -161 } -162 -163 pub(crate) fn get_local_nat_traversal_addresses(&self) -> Result<Vec<SocketAddr>, Error> { -164 match self { -165 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), -166 Self::ClientSide(client_state) => Ok(client_state -167 .local_addresses -168 .iter() -169 .copied() -170 .map(Into::into) -171 .collect()), -172 Self::ServerSide(server_state) => Ok(server_state -173 .local_addresses -174 .keys() -175 .copied() -176 .map(Into::into) -177 .collect()), -178 } -179 } -180} -181 -182#[derive(Debug)] -183pub(crate) struct ClientState { -184 /// Max number of remote addresses we allow -185 /// -186 /// This is set by the local endpoint. -187 max_remote_addresses: usize, -188 /// Max number of local addresses allowed -189 /// -190 /// This is set by the remote endpoint. -191 max_local_addresses: usize, -192 /// Candidate addresses the remote server reports as potentially reachable, to use for nat -193 /// traversal attempts. -194 /// -195 /// These are indexed by their advertised Id. For each address, whether the address should be -196 /// reported in nat traversal continuations is kept. -197 remote_addresses: FxHashMap<VarInt, (IpPort, bool)>, -198 /// Candidate addresses the local client reports as potentially reachable, to use for nat -199 /// traversal attempts. -200 local_addresses: FxHashSet<IpPort>, -201 /// Current nat traversal round. -202 round: VarInt, -203 /// [`PathId`]s used to probe remotes assigned to this round. -204 round_path_ids: Vec<PathId>, -205} -206 -207impl ClientState { -208 fn new(max_remote_addresses: usize, max_local_addresses: usize) -> Self { -209 Self { -210 max_remote_addresses, -211 max_local_addresses, -212 remote_addresses: Default::default(), -213 local_addresses: Default::default(), -214 round: Default::default(), -215 round_path_ids: Default::default(), -216 } -217 } -218 -219 fn add_local_address(&mut self, address: IpPort) -> Result<(), Error> { -220 if self.local_addresses.len() < self.max_local_addresses { -221 self.local_addresses.insert(address); -222 Ok(()) -223 } else if self.local_addresses.contains(&address) { -224 // at capacity, but the address is known, no issues here -225 Ok(()) -226 } else { -227 // at capacity and the address is new -228 Err(Error::TooManyAddresses) -229 } -230 } -231 -232 fn remove_local_address(&mut self, address: &IpPort) { -233 self.local_addresses.remove(address); -234 } -235 -236 /// Initiates a new nat traversal round. -237 /// -238 /// A nat traversal round involves advertising the client's local addresses in `REACH_OUT` -239 /// frames, and initiating probing of the known remote addresses. When a new round is -240 /// initiated, the previous one is cancelled, and paths that have not been opened should be -241 /// closed. -242 /// -243 /// `ipv6` indicates if the connection runs on a socket that supports IPv6. If so, then all -244 /// addresses returned in [`NatTraversalRound`] will be IPv6 addresses (and IPv4-mapped IPv6 -245 /// addresses if necessary). Otherwise they're all IPv4 addresses. -246 /// See also [`map_to_local_socket_family`]. -247 pub(crate) fn initiate_nat_traversal_round( -248 &mut self, -249 ipv6: bool, -250 ) -> Result<NatTraversalRound, Error> { -251 if self.local_addresses.is_empty() { -252 return Err(Error::NotEnoughAddresses); -253 } -254 -255 let prev_round_path_ids = std::mem::take(&mut self.round_path_ids); -256 self.round = self.round.saturating_add(1u8); -257 let mut addresses_to_probe = Vec::with_capacity(self.remote_addresses.len()); -258 for (id, ((ip, port), report_in_continuation)) in self.remote_addresses.iter_mut() { -259 *report_in_continuation = false; -260 -261 if let Some(ip) = map_to_local_socket_family(*ip, ipv6) { -262 addresses_to_probe.push((*id, (ip, *port))); -263 } else { -264 trace!(?ip, "not using IPv6 nat candidate for IPv4 socket"); -265 } -266 } -267 -268 Ok(NatTraversalRound { -269 new_round: self.round, -270 reach_out_at: self.local_addresses.iter().copied().collect(), -271 addresses_to_probe, -272 prev_round_path_ids, -273 }) -274 } -275 -276 /// Mark a remote address to be reported back in a nat traversal continuation if the error is -277 /// considered spurious from a nat traversal point of view. -278 /// -279 /// Ids not present are silently ignored. -280 pub(crate) fn report_in_continuation(&mut self, id: VarInt, e: crate::PathError) { -281 match e { -282 crate::PathError::MaxPathIdReached | crate::PathError::RemoteCidsExhausted => { -283 if let Some((_address, report_in_continuation)) = self.remote_addresses.get_mut(&id) -284 { -285 *report_in_continuation = true; -286 } -287 } -288 _ => {} -289 } -290 } -291 -292 /// Returns an address that needs to be probed, if any. -293 /// -294 /// The address will not be returned twice unless marked as such again with -295 /// [`Self::report_in_continuation`]. -296 /// -297 /// `ipv6` indicates if the connection runs on a socket that supports IPv6. If so, then all -298 /// addresses returned in [`NatTraversalRound`] will be IPv6 addresses (and IPv4-mapped IPv6 -299 /// addresses if necessary). Otherwise they're all IPv4 addresses. -300 /// See also [`map_to_local_socket_family`]. -301 pub(crate) fn continue_nat_traversal_round(&mut self, ipv6: bool) -> Option<(VarInt, IpPort)> { -302 // this being random depends on iteration not returning always on the same order -303 let (id, (address, report_in_continuation)) = self -304 .remote_addresses -305 .iter_mut() -306 .filter(|(_id, (_addr, report))| *report) -307 .filter_map(|(id, ((ip, port), report))| { -308 // only continue with addresses we can send on our local socket -309 let Some(ip) = map_to_local_socket_family(*ip, ipv6) else { -310 trace!(?ip, "not using IPv6 nat candidate for IPv4 socket"); -311 return None; -312 }; -313 Some((*id, ((ip, *port), report))) -314 }) -315 .next()?; -316 *report_in_continuation = false; -317 Some((id, address)) -318 } -319 -320 /// Add a [`PathId`] as part of the current attempts to create paths based on the server's -321 /// advertised addresses. -322 pub(crate) fn set_round_path_ids(&mut self, path_ids: Vec<PathId>) { -323 self.round_path_ids = path_ids; -324 } -325 -326 /// Add a [`PathId`] as part of the current attempts to create paths based on the server's -327 /// advertised addresses. -328 pub(crate) fn add_round_path_id(&mut self, path_id: PathId) { -329 self.round_path_ids.push(path_id); -330 } -331 -332 /// Adds an address to the remote set -333 /// -334 /// On success returns the address if it was new to the set. It will error when the set has no -335 /// capacity for the address. -336 pub(crate) fn add_remote_address( -337 &mut self, -338 add_addr: AddAddress, -339 ) -> Result<Option<SocketAddr>, Error> { -340 let AddAddress { seq_no, ip, port } = add_addr; -341 let address = (ip, port); -342 let allow_new = self.remote_addresses.len() < self.max_remote_addresses; -343 match self.remote_addresses.entry(seq_no) { -344 Entry::Occupied(mut occupied_entry) => { -345 let is_update = occupied_entry.get().0 != address; -346 if is_update { -347 occupied_entry.insert((address, false)); -348 } -349 // The value might be different. This should not happen, but we assume that the new -350 // address is more recent than the previous, and thus worth updating -351 Ok(is_update.then_some(address.into())) -352 } -353 Entry::Vacant(vacant_entry) if allow_new => { -354 vacant_entry.insert((address, false)); -355 Ok(Some(address.into())) -356 } -357 _ => Err(Error::TooManyAddresses), -358 } -359 } -360 -361 /// Removes an address from the remote set -362 /// -363 /// Returns whether the address was present. -364 pub(crate) fn remove_remote_address( -365 &mut self, -366 remove_addr: RemoveAddress, -367 ) -> Option<SocketAddr> { -368 self.remote_addresses -369 .remove(&remove_addr.seq_no) -370 .map(|(address, _report_in_continuation)| address.into()) -371 } -372 -373 /// Checks that a received remote address is valid -374 /// -375 /// An address is valid as long as it does not change the value of a known address id. -376 pub(crate) fn check_remote_address(&self, add_addr: &AddAddress) -> bool { -377 match self.remote_addresses.get(&add_addr.seq_no) { -378 None => true, -379 Some((existing, _)) => existing == &add_addr.ip_port(), -380 } -381 } -382 -383 pub(crate) fn get_remote_nat_traversal_addresses(&self) -> Vec<SocketAddr> { -384 self.remote_addresses -385 .values() -386 .map(|(address, _report_in_continuation)| (*address).into()) -387 .collect() +91 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), +92 Self::ClientSide(client_side) => Ok(client_side), +93 Self::ServerSide(_) => Err(Error::WrongConnectionSide), +94 } +95 } +96 +97 pub(crate) fn server_side_mut(&mut self) -> Result<&mut ServerState, Error> { +98 match self { +99 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), +100 Self::ClientSide(_) => Err(Error::WrongConnectionSide), +101 Self::ServerSide(server_side) => Ok(server_side), +102 } +103 } +104 +105 /// Adds a local address to use for nat traversal. +106 /// +107 /// When this endpoint is the server within the connection, these addresses will be sent to the +108 /// client in add address frames. For clients, these addresses will be sent in reach out frames +109 /// when nat traversal attempts are initiated. +110 /// +111 /// If a frame should be sent, it is returned. +112 pub(crate) fn add_local_address( +113 &mut self, +114 address: SocketAddr, +115 ) -> Result<Option<AddAddress>, Error> { +116 match self { +117 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), +118 Self::ClientSide(client_state) => { +119 client_state.add_local_address(address)?; +120 Ok(None) +121 } +122 Self::ServerSide(server_state) => server_state.add_local_address(address), +123 } +124 } +125 +126 /// Removes a local address from the advertised set for nat traversal. +127 /// +128 /// When this endpoint is the server, removed addresses must be reported with remove address +129 /// frames. Clients will simply stop reporting these addresses in reach out frames. +130 /// +131 /// If a frame should be sent, it is returned. +132 pub(crate) fn remove_local_address( +133 &mut self, +134 address: SocketAddr, +135 ) -> Result<Option<RemoveAddress>, Error> { +136 let address = IpPort::from((address.ip(), address.port())); +137 match self { +138 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), +139 Self::ClientSide(client_state) => { +140 client_state.remove_local_address(&address); +141 Ok(None) +142 } +143 Self::ServerSide(server_state) => Ok(server_state.remove_local_address(&address)), +144 } +145 } +146 +147 pub(crate) fn get_local_nat_traversal_addresses(&self) -> Result<Vec<SocketAddr>, Error> { +148 match self { +149 Self::NotNegotiated => Err(Error::ExtensionNotNegotiated), +150 Self::ClientSide(client_state) => Ok(client_state +151 .local_addresses +152 .iter() +153 .copied() +154 .map(Into::into) +155 .collect()), +156 Self::ServerSide(server_state) => Ok(server_state +157 .local_addresses +158 .keys() +159 .copied() +160 .map(Into::into) +161 .collect()), +162 } +163 } +164 +165 /// Returns the next ready probe's address. +166 /// +167 /// If this is actually sent you must call [`Self::mark_probe_sent`]. +168 pub(crate) fn next_probe_addr(&self) -> Option<SocketAddr> { +169 match self { +170 Self::NotNegotiated => None, +171 Self::ClientSide(state) => state.next_probe_addr(), +172 Self::ServerSide(state) => state.next_probe_addr(), +173 } +174 } +175 +176 /// Marks a probe as sent to the address with the challenge. +177 pub(crate) fn mark_probe_sent(&mut self, remote: IpPort, challenge: u64) { +178 match self { +179 Self::NotNegotiated => (), +180 Self::ClientSide(state) => state.mark_probe_sent(remote, challenge), +181 Self::ServerSide(state) => state.mark_probe_sent(remote, challenge), +182 } +183 } +184 +185 /// Re-queues probes that have not yet succeeded or reached 0 remaining retries. +186 /// +187 /// Returns whether any probes are now queued to send. In this case the +188 /// `NatTraversalProbeRetry` timer needs to be reset. +189 pub(crate) fn queue_retries(&mut self, ipv6: bool) -> bool { +190 match self { +191 Self::NotNegotiated => false, +192 Self::ClientSide(state) => state.queue_retries(ipv6), +193 Self::ServerSide(state) => state.queue_retries(), +194 } +195 } +196 +197 /// Marks a remote as successful if the response matches a sent probe. +198 /// +199 /// Returns the open network path if it was a response to one of the NAT traversal +200 /// probes. Note that the NAT probes are not padded to 1200 bytes so only the address is +201 /// validated, but not the entire path. +202 pub(crate) fn handle_path_response(&mut self, src: FourTuple, challenge: u64) -> bool { +203 match self { +204 Self::NotNegotiated => false, +205 Self::ClientSide(state) => state.handle_path_response(src, challenge), +206 Self::ServerSide(state) => state.handle_path_response(src, challenge), +207 } +208 } +209} +210 +211#[derive(Debug)] +212pub(crate) struct ClientState { +213 /// Max number of remote addresses we allow +214 /// +215 /// This is set by the local endpoint. +216 max_remote_addresses: usize, +217 /// Max number of local addresses allowed +218 /// +219 /// This is set by the remote endpoint. +220 max_local_addresses: usize, +221 /// Candidate addresses the remote endpoint advertises. +222 /// +223 /// These are addresses on which the server is potentially reachable, to use for NAT +224 /// traversal attempts. +225 /// +226 /// They are indexed by their ADD_ADDRESS sequence id and stored in **canonical +227 /// form**. Not in the socket-native form as usual. This because we need to store them +228 /// so we have the correct sequence IDs. +229 remote_addresses: FxHashMap<VarInt, (IpPort, ProbeState)>, +230 /// Candidate addresses for the local endpoint. +231 /// +232 /// These are addresses on which we are potentially reachable, to use for NAT traversal +233 /// attempts. +234 /// +235 /// They are stored in **canonical form**, not in socket-native form as usual. We may +236 /// nave a reflexive address that is IPv6 even if our local socket can only handle IPv4. +237 local_addresses: FxHashSet<IpPort>, +238 /// Current nat traversal round. +239 round: VarInt, +240 /// The data of PATH_CHALLENGE frames sent in probes. +241 /// +242 /// These are cleared when a new round starts, so any late-arriving PATH_RESPONSEs will +243 /// have no effect. +244 /// +245 /// They are stored in the usual socket-native form. +246 sent_challenges: FxHashMap<u64, IpPort>, +247 /// Queued probes to be sent in the next [`poll_transmit`] call. +248 /// +249 /// [`poll_transmit`]: crate::connection::Connection::poll_transmit +250 /// +251 /// They are stored in the usual socket-native form. Probes to address families not +252 /// addressable by the family are never inserted. +253 pending_probes: FxHashSet<IpPort>, +254 /// Network paths that were successfully probed but not yet opened. +255 /// +256 /// When we do not have enough CIDs or free path IDs we might not have been able to open +257 /// a new path. This allows us to try re-open the path when we get new CIDs or a new +258 /// MAX_PATH_ID. +259 // TODO(flub): perhaps there should be a time-limit on these? +260 paths_to_be_opened: Vec<FourTuple>, +261} +262 +263impl ClientState { +264 fn new(max_remote_addresses: usize, max_local_addresses: usize) -> Self { +265 Self { +266 max_remote_addresses, +267 max_local_addresses, +268 remote_addresses: Default::default(), +269 local_addresses: Default::default(), +270 round: Default::default(), +271 sent_challenges: Default::default(), +272 pending_probes: Default::default(), +273 paths_to_be_opened: Default::default(), +274 } +275 } +276 +277 fn add_local_address(&mut self, address: SocketAddr) -> Result<(), Error> { +278 let address = (address.ip().to_canonical(), address.port()); +279 if self.local_addresses.len() < self.max_local_addresses { +280 self.local_addresses.insert(address); +281 Ok(()) +282 } else if self.local_addresses.contains(&address) { +283 // at capacity, but the address is known, no issues here +284 Ok(()) +285 } else { +286 // at capacity and the address is new +287 Err(Error::TooManyAddresses) +288 } +289 } +290 +291 fn remove_local_address(&mut self, address: &IpPort) { +292 let address = (address.0.to_canonical(), address.1); +293 self.local_addresses.remove(&address); +294 } +295 +296 /// Initiates a new nat traversal round. +297 /// +298 /// A nat traversal round involves advertising the client's local addresses in +299 /// `REACH_OUT` frames, and initiating probing of the known remote addresses. When a new +300 /// round is initiated, the previous one is cancelled. +301 /// +302 /// `ipv6` indicates if the connection runs on a socket that supports IPv6. If so, then +303 /// all addresses returned [`PendingReachOutFrames`] will be IPv6 addresses (and +304 /// IPv4-mapped IPv6 addresses if necessary). Otherwise they're all IPv4 addresses. See +305 /// also [`map_to_local_socket_family`]. +306 /// +307 /// # Returns +308 /// +309 /// The REACH_OUT frames that need to be sent to the peer and the probed addresses. The +310 /// probed addresses are only informational, the pending probes are stored in +311 /// [`Self::pending_probes`]. +312 /// +313 /// If the probed addresses are non-empty the `NatTraversalProbeRetry` timer needs to be +314 /// set. +315 pub(crate) fn initiate_nat_traversal_round( +316 &mut self, +317 ipv6: bool, +318 ) -> Result<(PendingReachOutFrames, Vec<SocketAddr>), Error> { +319 if self.local_addresses.is_empty() { +320 return Err(Error::NotEnoughAddresses); +321 } +322 +323 self.round = self.round.saturating_add(1u8); +324 self.sent_challenges.clear(); +325 self.pending_probes.clear(); +326 +327 // Enqueue the NAT probes to known remote addresses. +328 self.remote_addresses +329 .values_mut() +330 .for_each(|((ip, port), state)| { +331 if let Some(ip) = map_to_local_socket_family(*ip, ipv6) { +332 self.pending_probes.insert((ip, *port)); +333 *state = ProbeState::Active(MAX_NAT_PROBE_ATTEMPTS - 1); +334 } else { +335 trace!(?ip, "not using IPv6 NAT candidate for IPv4 socket"); +336 *state = ProbeState::Active(0); +337 } +338 }); +339 let probed_addrs: Vec<SocketAddr> = self +340 .pending_probes +341 .iter() +342 .copied() +343 .map(Into::into) +344 .collect(); +345 +346 // Build the REACH_OUT frames. +347 let reach_out_frames: PendingReachOutFrames = self +348 .local_addresses +349 .iter() +350 .map(|&(ip, port)| ReachOut { +351 round: self.round, +352 ip, +353 port, +354 }) +355 .collect(); +356 +357 trace!( +358 round = %self.round, +359 reach_out = %reach_out_frames.len(), +360 to_probe = %self.pending_probes.len(), +361 "initiating NAT traversal round", +362 ); +363 Ok((reach_out_frames, probed_addrs)) +364 } +365 +366 /// Re-queues probes that have not yet succeeded or reached 0 remaining retries. +367 /// +368 /// Returns whether any probes are now queued to send. In this case the +369 /// `NatTraversalProbeRetry` timer needs to be reset. +370 /// +371 /// `ipv6` as for [`Self::initiate_nat_traversal_round`]. +372 pub(crate) fn queue_retries(&mut self, ipv6: bool) -> bool { +373 self.remote_addresses +374 .values_mut() +375 .for_each(|(addr, state)| match state { +376 ProbeState::Active(remaining) if *remaining > 0 => { +377 *remaining -= 1; +378 if let Some(ip) = map_to_local_socket_family(addr.0, ipv6) { +379 self.pending_probes.insert((ip, addr.1)); +380 } else { +381 trace!(?addr, "skipping IPv6 NAT candidate for IPv4 socket"); +382 *remaining = 0; +383 } +384 } +385 ProbeState::Active(_) | ProbeState::Succeeded => {} +386 }); +387 !self.pending_probes.is_empty() 388 } -389} -390 -391/// Maximum number of times we send a NAT probe to the same remote address in a round. -392/// -393/// This is a trade-off between several factors: -394/// - Probe packets could be lost. This allows recovery. -395/// - We may need two probes to reach the NAT firewall to get through. -396/// - We may be sending probes to innocent bystanders on the internet. -397/// - A round never "finishes": probing of remotes only stops when: -398/// 1. A new round is started. -399/// 2. A probe was successful. -400/// 3. This number of attempts is exhausted. -401/// -402/// Currently probes are retried after 2/3rd of the configured initial RTT. At a -403/// fixed interval, so without exponential backoff. For the default initial RTT of 333ms -404/// this is 222ms. So 10 attempts covers 2220ms. -405// TODO(flub): I would like to improve this sometime so that we cover about 2s but with only -406// about 5-6 probes. The three initial probes should be faster, later probes should start -407// to slow down. Unfortunately we only have one timer for the entire round currently, we -408// would need to have a timer per remote. Because REACH_OUT frames can appear in the -409// middle of a round. -410pub(crate) const MAX_NAT_PROBE_ATTEMPTS: u8 = 10; -411 -412/// State of an off-path NAT traversal probe to a remote address. -413#[derive(Debug)] -414enum ProbeState { -415 /// The remote still needs to be probed in this round. -416 /// -417 /// The remaining number of retries are stored in the `u8`. -418 Active(u8), -419 /// We received a probe response for this remote. -420 Succeeded, -421} -422 -423#[derive(Debug)] -424pub(crate) struct ServerState { -425 /// Max number of remote addresses we allow. -426 /// -427 /// This is set by the local endpoint. -428 max_remote_addresses: usize, -429 /// Max number of local addresses allowed. -430 /// -431 /// This is set by the remote endpoint. -432 max_local_addresses: usize, -433 /// Candidate addresses the server reports as potentially reachable, to use for nat -434 /// traversal attempts. -435 local_addresses: FxHashMap<IpPort, VarInt>, -436 /// The next id to use for local addresses sent to the client. -437 next_local_addr_id: VarInt, -438 /// Current nat traversal round -439 /// -440 /// Servers keep track of the client's most recent round and cancel probing related to previous -441 /// rounds. -442 round: VarInt, -443 /// The remote addresses participating in this round. -444 /// -445 /// The set is cleared when a new round starts. -446 remotes: FxHashMap<IpPort, ProbeState>, -447 /// The data of PATH_CHALLENGE frames sent in probes. -448 /// -449 /// These are cleared when a new round starts, so any late-arriving PATH_RESPONSEs will -450 /// have no effect. -451 sent_challenges: FxHashMap<u64, IpPort>, -452 /// Queued probes to be sent in the next [`poll_transmit`] call. -453 /// -454 /// At the beginning of a round this is populated from REACH_OUT frames and at every -455 /// retry this is populated from [`Self::remotes`]. -456 /// -457 /// [`poll_transmit`]: crate::connection::Connection::poll_transmit -458 pending_probes: FxHashSet<IpPort>, -459} +389 +390 /// Returns the next ready probe's address. +391 /// +392 /// If this is actually sent you must call [`Self::mark_probe_sent`]. +393 fn next_probe_addr(&self) -> Option<SocketAddr> { +394 self.pending_probes.iter().next().map(|addr| (*addr).into()) +395 } +396 +397 /// Marks a probe as sent to the address with the challenge. +398 fn mark_probe_sent(&mut self, remote: IpPort, challenge: u64) { +399 self.pending_probes.remove(&remote); +400 self.sent_challenges.insert(challenge, remote); +401 } +402 +403 /// Adds an address to the remote set +404 /// +405 /// On success returns the address if it was new to the set. It will error when the set +406 /// has no capacity for the address. +407 /// +408 /// If this is called while a round is in progress this will effectively add the address +409 /// to the current round. There is no guarantee however that the current round is still +410 /// in progress however, if the last [`Self::queue_retries`] call returned `false` the +411 /// round has stopped. +412 // TODO(flub): probably should add an event to signal that the round is finished, so +413 // that the application knows to start a new round. +414 pub(crate) fn add_remote_address( +415 &mut self, +416 add_addr: AddAddress, +417 ) -> Result<Option<SocketAddr>, Error> { +418 let AddAddress { seq_no, ip, port } = add_addr; +419 let address = (ip.to_canonical(), port); +420 let allow_new = self.remote_addresses.len() < self.max_remote_addresses; +421 match self.remote_addresses.entry(seq_no) { +422 Entry::Occupied(mut occupied_entry) => { +423 let is_update = occupied_entry.get().0 != address; +424 if is_update { +425 occupied_entry.insert((address, ProbeState::Active(MAX_NAT_PROBE_ATTEMPTS))); +426 } +427 // The value might be different. This should not happen, but we assume that the new +428 // address is more recent than the previous, and thus worth updating +429 Ok(is_update.then_some(address.into())) +430 } +431 Entry::Vacant(vacant_entry) if allow_new => { +432 vacant_entry.insert((address, ProbeState::Active(MAX_NAT_PROBE_ATTEMPTS))); +433 Ok(Some(address.into())) +434 } +435 _ => Err(Error::TooManyAddresses), +436 } +437 } +438 +439 /// Removes an address from the remote set. +440 /// +441 /// Returns whether the address was present. +442 pub(crate) fn remove_remote_address( +443 &mut self, +444 remove_addr: RemoveAddress, +445 ) -> Option<SocketAddr> { +446 self.remote_addresses +447 .remove(&remove_addr.seq_no) +448 .map(|(address, _)| address.into()) +449 } +450 +451 /// Checks that a received remote address is valid. +452 /// +453 /// An address is valid as long as it does not change the value of a known address id. +454 pub(crate) fn check_remote_address(&self, add_addr: &AddAddress) -> bool { +455 match self.remote_addresses.get(&add_addr.seq_no) { +456 None => true, +457 Some((existing, _)) => existing == &add_addr.ip_port(), +458 } +459 } 460 -461impl ServerState { -462 fn new(max_remote_addresses: usize, max_local_addresses: usize) -> Self { -463 Self { -464 max_remote_addresses, -465 max_local_addresses, -466 local_addresses: Default::default(), -467 next_local_addr_id: Default::default(), -468 round: Default::default(), -469 remotes: Default::default(), -470 sent_challenges: Default::default(), -471 pending_probes: Default::default(), -472 } -473 } -474 -475 fn add_local_address(&mut self, address: IpPort) -> Result<Option<AddAddress>, Error> { -476 let allow_new = self.local_addresses.len() < self.max_local_addresses; -477 match self.local_addresses.entry(address) { -478 Entry::Occupied(_) => Ok(None), -479 Entry::Vacant(vacant_entry) if allow_new => { -480 let id = self.next_local_addr_id; -481 self.next_local_addr_id = self.next_local_addr_id.saturating_add(1u8); -482 vacant_entry.insert(id); -483 Ok(Some(AddAddress::new(address, id))) -484 } -485 _ => Err(Error::TooManyAddresses), -486 } -487 } -488 -489 fn remove_local_address(&mut self, address: &IpPort) -> Option<RemoveAddress> { -490 self.local_addresses.remove(address).map(RemoveAddress::new) -491 } -492 -493 /// Returns the current NAT traversal round number. -494 pub(crate) fn current_round(&self) -> VarInt { -495 self.round -496 } -497 -498 /// Handles a received REACH_OUT frame. -499 /// -500 /// This might ignore the reach out frame if it belongs to an older round or if the -501 /// frame contains an IPv6 address while the local socket is IPv4-only. -502 /// -503 /// If a new round was started, the `NatTraversalProbeRetry` timer needs to be reset. -504 pub(crate) fn handle_reach_out( -505 &mut self, -506 reach_out: ReachOut, -507 ipv6: bool, -508 ) -> Result<(), Error> { -509 let ReachOut { round, ip, port } = reach_out; -510 -511 if round < self.round { -512 trace!(current_round=%self.round, "ignoring REACH_OUT for previous round"); -513 return Ok(()); -514 } -515 let Some(ip) = map_to_local_socket_family(ip, ipv6) else { -516 trace!("Ignoring IPv6 REACH_OUT frame due to not supporting IPv6 locally"); -517 return Ok(()); -518 }; +461 pub(crate) fn get_remote_nat_traversal_addresses(&self) -> Vec<SocketAddr> { +462 self.remote_addresses +463 .values() +464 .map(|(address, _)| (*address).into()) +465 .collect() +466 } +467 +468 /// Marks a remote as successful if the response matches a sent probe. +469 /// +470 /// Returns `true` if it was a response to one of the NAT traversal probes. In that case +471 /// [`Self::pop_pending_path_open`] should be called to open the next path. +472 fn handle_path_response(&mut self, network_path: FourTuple, challenge: u64) -> bool { +473 if let Entry::Occupied(entry) = self.sent_challenges.entry(challenge) { +474 let remote = (network_path.remote().ip(), network_path.remote().port()); +475 if *entry.get() == remote { +476 entry.remove(); +477 +478 // self.remote_addresses is stored in canonical form. +479 let remote = (remote.0.to_canonical(), remote.1); +480 // TODO: linear search is sad. +481 if let Some(seq) = self +482 .remote_addresses +483 .iter() +484 .filter_map( +485 |(seq, (addr, _))| { +486 if *addr == remote { Some(*seq) } else { None } +487 }, +488 ) +489 .next() +490 { +491 trace!( +492 ?network_path, +493 challenge = %display(format_args!("0x{challenge:x}")), +494 "Received valid NAT traversal probe response", +495 ); +496 self.remote_addresses +497 .insert(seq, (remote, ProbeState::Succeeded)); +498 self.paths_to_be_opened.push(network_path); +499 return true; +500 } else { +501 debug!("inconsistent remote addrs and seq"); +502 } +503 } else { +504 debug!( +505 ?network_path.remote, +506 expected_remote = ?entry.get(), +507 challenge = %display(format_args!("0x{challenge:x}")), +508 "PATH_RESPONSE matched a NAT traversal probe but mismatching addr XXXX", +509 ) +510 } +511 } +512 false +513 } +514 +515 /// Returns a path that was NAT traversed and needs to be opened. +516 pub(crate) fn pop_pending_path_open(&mut self) -> Option<FourTuple> { +517 self.paths_to_be_opened.pop() +518 } 519 -520 if round > self.round { -521 self.round = round; -522 self.remotes.clear(); -523 self.sent_challenges.clear(); -524 self.pending_probes.clear(); -525 } else if self.remotes.contains_key(&(ip, port)) { -526 // Retransmitted frame. -527 return Ok(()); -528 } else if self.remotes.len() >= self.max_remote_addresses { -529 return Err(Error::TooManyAddresses); -530 } -531 self.remotes -532 .entry((ip, port)) -533 .or_insert(ProbeState::Active(MAX_NAT_PROBE_ATTEMPTS - 1)); -534 self.pending_probes.insert((ip, port)); -535 Ok(()) -536 } -537 -538 /// Re-queues probes that have not yet succeeded or reached [`MAX_NAT_PROBE_ATTEMPTS`]. -539 /// -540 /// Returns whether any probes are now queued to send. In this case the -541 /// `NatTraversalProbeRetry` timer needs to be reset. -542 pub(crate) fn queue_retries(&mut self) -> bool { -543 self.remotes -544 .iter_mut() -545 .for_each(|(remote, state)| match state { -546 ProbeState::Active(remaining) if *remaining > 0 => { -547 *remaining -= 1; -548 self.pending_probes.insert(*remote); -549 } -550 ProbeState::Active(_) | ProbeState::Succeeded => (), -551 }); -552 !self.pending_probes.is_empty() -553 } -554 -555 /// Returns the next ready probe's address. -556 /// -557 /// If this is actually sent you must call [`Self::mark_probe_sent`]. -558 pub(crate) fn next_probe_addr(&self) -> Option<SocketAddr> { -559 self.pending_probes.iter().next().map(|addr| (*addr).into()) -560 } -561 -562 /// Marks a probe as sent to the address with the challenge. -563 pub(crate) fn mark_probe_sent(&mut self, remote: IpPort, challenge: u64) { -564 self.pending_probes.remove(&remote); -565 self.sent_challenges.insert(challenge, remote); -566 } -567 -568 /// Marks a remote as successful if the response matches a sent probe. -569 /// -570 /// Returns `true` if it was a response to one of the NAT traversal probes. -571 pub(crate) fn handle_path_response(&mut self, src: FourTuple, challenge: u64) -> bool { -572 if let Entry::Occupied(entry) = self.sent_challenges.entry(challenge) { -573 let remote = (src.remote().ip(), src.remote().port()); -574 if *entry.get() == remote { -575 entry.remove(); -576 self.remotes.insert(remote, ProbeState::Succeeded); -577 return true; -578 } else { -579 debug!( -580 ?challenge, -581 ?src.remote, -582 "PATH_RESPONSE matched a NAT traversal probe but mismatching addr", -583 ) -584 } -585 } -586 false -587 } -588} -589 -590/// Returns the given address as canonicalized IP address. -591/// -592/// This checks that the address family is supported by our local socket. -593/// If it is supported, then the address is mapped to the respective IP address. -594/// If the given address is an IPv6 address, but our local socket doesn't support -595/// IPv6, then this returns `None`. -596pub(crate) fn map_to_local_socket_family(address: IpAddr, ipv6: bool) -> Option<IpAddr> { -597 let ip = match address { -598 IpAddr::V4(addr) if ipv6 => IpAddr::V6(addr.to_ipv6_mapped()), -599 IpAddr::V4(_) => address, -600 IpAddr::V6(_) if ipv6 => address, -601 IpAddr::V6(addr) => IpAddr::V4(addr.to_ipv4_mapped()?), -602 }; -603 Some(ip) -604} -605 -606#[cfg(test)] -607mod tests { -608 use super::*; -609 -610 #[test] -611 fn test_basic_server_state() { -612 let mut state = ServerState::new(2, 2); -613 -614 state -615 .handle_reach_out( -616 ReachOut { -617 round: 1u32.into(), -618 ip: std::net::Ipv4Addr::LOCALHOST.into(), -619 port: 1, -620 }, -621 true, -622 ) -623 .unwrap(); -624 -625 state -626 .handle_reach_out( -627 ReachOut { -628 round: 1u32.into(), -629 ip: "1.1.1.1".parse().unwrap(), //std::net::Ipv4Addr::LOCALHOST.into(), -630 port: 2, -631 }, -632 true, -633 ) -634 .unwrap(); -635 -636 dbg!(&state); -637 assert_eq!(state.pending_probes.len(), 2); +520 /// Put back a path that needs to be opened, e.g. for a temporary failure. +521 pub(crate) fn push_pending_path_open(&mut self, network_path: FourTuple) { +522 self.paths_to_be_opened.push(network_path) +523 } +524} +525 +526/// Maximum number of times we send a NAT probe to the same remote address in a round. +527/// +528/// This is a trade-off between several factors: +529/// - Probe packets could be lost. This allows recovery. +530/// - We may need two probes to reach the NAT firewall to get through. +531/// - We may be sending probes to innocent bystanders on the internet. +532/// - A round never "finishes": probing of remotes only stops when: +533/// 1. A new round is started. +534/// 2. A probe was successful. +535/// 3. This number of attempts is exhausted. +536/// +537/// Currently probes are retried after 2/3rd of the configured initial RTT. At a +538/// fixed interval, so without exponential backoff. For the default initial RTT of 333ms +539/// this is 222ms. So 10 attempts covers 2220ms. +540// TODO(flub): I would like to improve this sometime so that we cover about 2s but with only +541// about 5-6 probes. The three initial probes should be faster, later probes should start +542// to slow down. Unfortunately we only have one timer for the entire round currently, we +543// would need to have a timer per remote. Because REACH_OUT frames can appear in the +544// middle of a round. +545pub(crate) const MAX_NAT_PROBE_ATTEMPTS: u8 = 10; +546 +547/// State of an off-path NAT traversal probe to a remote address. +548#[derive(Debug)] +549enum ProbeState { +550 /// The remote still needs to be probed in this round. +551 /// +552 /// The remaining number of retries are stored in the `u8`. +553 Active(u8), +554 /// We received a probe response for this remote. +555 Succeeded, +556} +557 +558#[derive(Debug)] +559pub(crate) struct ServerState { +560 /// Max number of remote addresses we allow. +561 /// +562 /// This is set by the local endpoint. +563 max_remote_addresses: usize, +564 /// Max number of local addresses allowed. +565 /// +566 /// This is set by the remote endpoint. +567 max_local_addresses: usize, +568 /// Candidate addresses the server reports as potentially reachable, to use for nat +569 /// traversal attempts. +570 /// +571 /// They are stored in **canonical form**, not in socket-native form as usual. We may +572 /// nave a reflexive address that is IPv6 even if our local socket can only handle IPv4. +573 local_addresses: FxHashMap<IpPort, VarInt>, +574 /// The next id to use for local addresses sent to the client. +575 next_local_addr_id: VarInt, +576 /// Current nat traversal round +577 /// +578 /// Servers keep track of the client's most recent round and cancel probing related to previous +579 /// rounds. +580 round: VarInt, +581 /// The remote addresses participating in this round. +582 /// +583 /// The set is cleared when a new round starts. +584 /// +585 /// These are stored in the usual local-socket native form. +586 remotes: FxHashMap<IpPort, ProbeState>, +587 /// The data of PATH_CHALLENGE frames sent in probes. +588 /// +589 /// These are cleared when a new round starts, so any late-arriving PATH_RESPONSEs will +590 /// have no effect. +591 sent_challenges: FxHashMap<u64, IpPort>, +592 /// Queued probes to be sent in the next [`poll_transmit`] call. +593 /// +594 /// At the beginning of a round this is populated from REACH_OUT frames and at every +595 /// retry this is populated from [`Self::remotes`]. +596 /// +597 /// [`poll_transmit`]: crate::connection::Connection::poll_transmit +598 pending_probes: FxHashSet<IpPort>, +599} +600 +601impl ServerState { +602 fn new(max_remote_addresses: usize, max_local_addresses: usize) -> Self { +603 Self { +604 max_remote_addresses, +605 max_local_addresses, +606 local_addresses: Default::default(), +607 next_local_addr_id: Default::default(), +608 round: Default::default(), +609 remotes: Default::default(), +610 sent_challenges: Default::default(), +611 pending_probes: Default::default(), +612 } +613 } +614 +615 fn add_local_address(&mut self, address: SocketAddr) -> Result<Option<AddAddress>, Error> { +616 let address = (address.ip().to_canonical(), address.port()); +617 let allow_new = self.local_addresses.len() < self.max_local_addresses; +618 match self.local_addresses.entry(address) { +619 Entry::Occupied(_) => Ok(None), +620 Entry::Vacant(vacant_entry) if allow_new => { +621 let id = self.next_local_addr_id; +622 self.next_local_addr_id = self.next_local_addr_id.saturating_add(1u8); +623 vacant_entry.insert(id); +624 Ok(Some(AddAddress::new(address, id))) +625 } +626 _ => Err(Error::TooManyAddresses), +627 } +628 } +629 +630 fn remove_local_address(&mut self, address: &IpPort) -> Option<RemoveAddress> { +631 self.local_addresses.remove(address).map(RemoveAddress::new) +632 } +633 +634 /// Returns the current NAT traversal round number. +635 pub(crate) fn current_round(&self) -> VarInt { +636 self.round +637 } 638 -639 // Helper: send next ready probe -640 let mut challenge = 0; -641 let mut send_probe = |state: &mut ServerState| { -642 let remote = state.next_probe_addr().unwrap(); -643 challenge += 1; -644 state.mark_probe_sent((remote.ip(), remote.port()), challenge); -645 }; -646 -647 send_probe(&mut state); -648 send_probe(&mut state); -649 -650 // After sending both probes, no ready probes remain but they're still tracked. -651 assert!(state.next_probe_addr().is_none()); -652 -653 // After queuing retries, probes become available again -654 assert!(state.queue_retries()); -655 send_probe(&mut state); -656 send_probe(&mut state); -657 -658 // After 2 attempts each, retries still available (max is 10) -659 assert!(state.queue_retries()); -660 send_probe(&mut state); -661 send_probe(&mut state); -662 -663 // Exhaust remaining attempts -664 for _ in 3..MAX_NAT_PROBE_ATTEMPTS { -665 assert!(state.queue_retries()); -666 send_probe(&mut state); -667 send_probe(&mut state); -668 } -669 -670 // After max attempts, probes are removed -671 assert!(!state.queue_retries()); -672 assert!(state.next_probe_addr().is_none()); -673 } -674 -675 #[test] -676 fn test_map_to_local_socket() { -677 assert_eq!( -678 map_to_local_socket_family("1.1.1.1".parse().unwrap(), false), -679 Some("1.1.1.1".parse().unwrap()) -680 ); -681 assert_eq!( -682 map_to_local_socket_family("1.1.1.1".parse().unwrap(), true), -683 Some("::ffff:1.1.1.1".parse().unwrap()) -684 ); -685 assert_eq!( -686 map_to_local_socket_family("::1".parse().unwrap(), true), -687 Some("::1".parse().unwrap()) -688 ); -689 assert_eq!( -690 map_to_local_socket_family("::1".parse().unwrap(), false), -691 None -692 ); -693 assert_eq!( -694 map_to_local_socket_family("::ffff:1.1.1.1".parse().unwrap(), false), -695 Some("1.1.1.1".parse().unwrap()) -696 ) -697 } -698} \ No newline at end of file +639 /// Handles a received REACH_OUT frame. +640 /// +641 /// This might ignore the reach out frame if it belongs to an older round or if the +642 /// frame contains an IPv6 address while the local socket is IPv4-only. +643 /// +644 /// If a new round was started, the `NatTraversalProbeRetry` timer needs to be reset. +645 pub(crate) fn handle_reach_out( +646 &mut self, +647 reach_out: ReachOut, +648 ipv6: bool, +649 ) -> Result<(), Error> { +650 let ReachOut { round, ip, port } = reach_out; +651 +652 if round < self.round { +653 trace!(current_round=%self.round, "ignoring REACH_OUT for previous round"); +654 return Ok(()); +655 } +656 let Some(ip) = map_to_local_socket_family(ip, ipv6) else { +657 trace!("Ignoring IPv6 REACH_OUT frame due to not supporting IPv6 locally"); +658 return Ok(()); +659 }; +660 +661 if round > self.round { +662 self.round = round; +663 self.remotes.clear(); +664 self.sent_challenges.clear(); +665 self.pending_probes.clear(); +666 } else if self.remotes.contains_key(&(ip, port)) { +667 // Retransmitted frame. +668 return Ok(()); +669 } else if self.remotes.len() >= self.max_remote_addresses { +670 return Err(Error::TooManyAddresses); +671 } +672 self.remotes +673 .entry((ip, port)) +674 .or_insert(ProbeState::Active(MAX_NAT_PROBE_ATTEMPTS - 1)); +675 self.pending_probes.insert((ip, port)); +676 Ok(()) +677 } +678 +679 /// Re-queues probes that have not yet succeeded or reached [`MAX_NAT_PROBE_ATTEMPTS`]. +680 /// +681 /// Returns whether any probes are now queued to send. In this case the +682 /// `NatTraversalProbeRetry` timer needs to be reset. +683 pub(crate) fn queue_retries(&mut self) -> bool { +684 self.remotes +685 .iter_mut() +686 .for_each(|(remote, state)| match state { +687 ProbeState::Active(remaining) if *remaining > 0 => { +688 *remaining -= 1; +689 self.pending_probes.insert(*remote); +690 } +691 ProbeState::Active(_) | ProbeState::Succeeded => (), +692 }); +693 !self.pending_probes.is_empty() +694 } +695 +696 /// Returns the next ready probe's address. +697 /// +698 /// If this is actually sent you must call [`Self::mark_probe_sent`]. +699 fn next_probe_addr(&self) -> Option<SocketAddr> { +700 self.pending_probes.iter().next().map(|addr| (*addr).into()) +701 } +702 +703 /// Marks a probe as sent to the address with the challenge. +704 fn mark_probe_sent(&mut self, remote: IpPort, challenge: u64) { +705 self.pending_probes.remove(&remote); +706 self.sent_challenges.insert(challenge, remote); +707 } +708 +709 /// Marks a remote as successful if the response matches a sent probe. +710 /// +711 /// Returns `true` if it was a response to one of the NAT traversal probes. +712 fn handle_path_response(&mut self, src: FourTuple, challenge: u64) -> bool { +713 if let Entry::Occupied(entry) = self.sent_challenges.entry(challenge) { +714 let remote = (src.remote().ip(), src.remote().port()); +715 if *entry.get() == remote { +716 entry.remove(); +717 self.remotes.insert(remote, ProbeState::Succeeded); +718 return true; +719 } else { +720 debug!( +721 ?challenge, +722 ?src.remote, +723 "PATH_RESPONSE matched a NAT traversal probe but mismatching addr", +724 ) +725 } +726 } +727 false +728 } +729} +730 +731/// Returns the given address as canonicalized IP address. +732/// +733/// This checks that the address family is supported by our local socket. +734/// If it is supported, then the address is mapped to the respective IP address. +735/// If the given address is an IPv6 address, but our local socket doesn't support +736/// IPv6, then this returns `None`. +737pub(crate) fn map_to_local_socket_family(address: IpAddr, ipv6: bool) -> Option<IpAddr> { +738 let ip = match address { +739 IpAddr::V4(addr) if ipv6 => IpAddr::V6(addr.to_ipv6_mapped()), +740 IpAddr::V4(_) => address, +741 IpAddr::V6(_) if ipv6 => address, +742 IpAddr::V6(addr) => IpAddr::V4(addr.to_ipv4_mapped()?), +743 }; +744 Some(ip) +745} +746 +747#[cfg(test)] +748mod tests { +749 use super::*; +750 +751 #[test] +752 fn test_basic_server_state() { +753 let mut state = ServerState::new(2, 2); +754 +755 state +756 .handle_reach_out( +757 ReachOut { +758 round: 1u32.into(), +759 ip: std::net::Ipv4Addr::LOCALHOST.into(), +760 port: 1, +761 }, +762 true, +763 ) +764 .unwrap(); +765 +766 state +767 .handle_reach_out( +768 ReachOut { +769 round: 1u32.into(), +770 ip: "1.1.1.1".parse().unwrap(), //std::net::Ipv4Addr::LOCALHOST.into(), +771 port: 2, +772 }, +773 true, +774 ) +775 .unwrap(); +776 +777 dbg!(&state); +778 assert_eq!(state.pending_probes.len(), 2); +779 +780 // Helper: send next ready probe +781 let mut challenge = 0; +782 let mut send_probe = |state: &mut ServerState| { +783 let remote = state.next_probe_addr().unwrap(); +784 challenge += 1; +785 state.mark_probe_sent((remote.ip(), remote.port()), challenge); +786 }; +787 +788 send_probe(&mut state); +789 send_probe(&mut state); +790 +791 // After sending both probes, no ready probes remain but they're still tracked. +792 assert!(state.next_probe_addr().is_none()); +793 +794 // After queuing retries, probes become available again +795 assert!(state.queue_retries()); +796 send_probe(&mut state); +797 send_probe(&mut state); +798 +799 // After 2 attempts each, retries still available (max is 10) +800 assert!(state.queue_retries()); +801 send_probe(&mut state); +802 send_probe(&mut state); +803 +804 // Exhaust remaining attempts +805 for _ in 3..MAX_NAT_PROBE_ATTEMPTS { +806 assert!(state.queue_retries()); +807 send_probe(&mut state); +808 send_probe(&mut state); +809 } +810 +811 // After max attempts, probes are removed +812 assert!(!state.queue_retries()); +813 assert!(state.next_probe_addr().is_none()); +814 } +815 +816 #[test] +817 fn test_map_to_local_socket() { +818 assert_eq!( +819 map_to_local_socket_family("1.1.1.1".parse().unwrap(), false), +820 Some("1.1.1.1".parse().unwrap()) +821 ); +822 assert_eq!( +823 map_to_local_socket_family("1.1.1.1".parse().unwrap(), true), +824 Some("::ffff:1.1.1.1".parse().unwrap()) +825 ); +826 assert_eq!( +827 map_to_local_socket_family("::1".parse().unwrap(), true), +828 Some("::1".parse().unwrap()) +829 ); +830 assert_eq!( +831 map_to_local_socket_family("::1".parse().unwrap(), false), +832 None +833 ); +834 assert_eq!( +835 map_to_local_socket_family("::ffff:1.1.1.1".parse().unwrap(), false), +836 Some("1.1.1.1".parse().unwrap()) +837 ) +838 } +839} \ No newline at end of file