From f55dbaf8d04f82e6ef46c82fa5cc1380604fc2e1 Mon Sep 17 00:00:00 2001
From: Benjamin Saunders <ben.e.saunders@gmail.com>
Date: Tue, 16 Apr 2019 07:42:45 -0700
Subject: [PATCH] Hack around broken macOS ECN ABI

---
 quinn/src/platform/unix.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/quinn/src/platform/unix.rs b/quinn/src/platform/unix.rs
index 4fb1d1907..4de447d2f 100644
--- a/quinn/src/platform/unix.rs
+++ b/quinn/src/platform/unix.rs
@@ -158,7 +158,16 @@ impl super::UdpExt for UdpSocket {
                     cmsg::decode::<u8>(cmsg)
                 },
                 (libc::IPPROTO_IPV6, libc::IPV6_TCLASS) => unsafe {
-                    cmsg::decode::<libc::c_int>(cmsg) as u8
+                    // Temporary hack around broken macos ABI. Remove once upstream fixes it.
+                    // https://bugreport.apple.com/web/?problemID=48761855
+                    if cfg!(target_os = "macos")
+                        && cmsg.cmsg_len as usize
+                            == libc::CMSG_LEN(mem::size_of::<u8>() as _) as usize
+                    {
+                        cmsg::decode::<u8>(cmsg)
+                    } else {
+                        cmsg::decode::<libc::c_int>(cmsg) as u8
+                    }
                 },
                 _ => 0,
             },