From 446cd72e38b079ccd0c867138044e073e87ca03c Mon Sep 17 00:00:00 2001
From: Dirkjan Ochtman <dirkjan@ochtman.nl>
Date: Mon, 21 Jul 2025 12:18:35 +0200
Subject: [PATCH] proto: fix NewConnectionId size bound

---
 quinn-proto/src/connection/mod.rs | 4 ++--
 quinn-proto/src/frame.rs          | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/quinn-proto/src/connection/mod.rs b/quinn-proto/src/connection/mod.rs
index 0152d9b81..a877421a5 100644
--- a/quinn-proto/src/connection/mod.rs
+++ b/quinn-proto/src/connection/mod.rs
@@ -28,7 +28,7 @@ use crate::{
     coding::BufMutExt,
     config::{ServerConfig, TransportConfig},
     crypto::{self, KeyPair, Keys, PacketKey},
-    frame::{self, Close, Datagram, FrameStruct, NewToken},
+    frame::{self, Close, Datagram, FrameStruct, NewConnectionId, NewToken},
     packet::{
         FixedLengthConnectionIdParser, Header, InitialHeader, InitialPacket, LongType, Packet,
         PacketNumber, PartialDecode, SpaceId,
@@ -3334,7 +3334,7 @@ impl Connection {
         }
 
         // NEW_CONNECTION_ID
-        while buf.len() + 44 < max_size {
+        while buf.len() + NewConnectionId::SIZE_BOUND < max_size {
             let issued = match space.pending.new_cids.pop() {
                 Some(x) => x,
                 None => break,
diff --git a/quinn-proto/src/frame.rs b/quinn-proto/src/frame.rs
index 21fe0340c..01d9a0264 100644
--- a/quinn-proto/src/frame.rs
+++ b/quinn-proto/src/frame.rs
@@ -884,6 +884,10 @@ impl NewConnectionId {
     }
 }
 
+impl FrameStruct for NewConnectionId {
+    const SIZE_BOUND: usize = 1 + 8 + 8 + 1 + MAX_CID_SIZE + RESET_TOKEN_SIZE;
+}
+
 /// Smallest number of bytes this type of frame is guaranteed to fit within.
 pub(crate) const RETIRE_CONNECTION_ID_SIZE_BOUND: usize = 9;