[manual] Merge release/9.0-staging into release/9.0 (second pass)

src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.cs

@@ -3602,15 +3602,15 @@ internal void InternalSetBlocking(bool desired)
         }
 
         // CreateAcceptSocket - pulls unmanaged results and assembles them into a new Socket object.
-        internal Socket CreateAcceptSocket(SafeSocketHandle fd, EndPoint remoteEP)
+        internal Socket CreateAcceptSocket(SafeSocketHandle fd, EndPoint? remoteEP)
         {
             // Internal state of the socket is inherited from listener.
             Debug.Assert(fd != null && !fd.IsInvalid);
             Socket socket = new Socket(fd, loadPropertiesFromHandle: false);
             return UpdateAcceptSocket(socket, remoteEP);
         }
 
-        internal Socket UpdateAcceptSocket(Socket socket, EndPoint remoteEP)
+        internal Socket UpdateAcceptSocket(Socket socket, EndPoint? remoteEP)
         {
             // Internal state of the socket is inherited from listener.
             socket._addressFamily = _addressFamily;

src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncEventArgs.Unix.cs

@@ -35,7 +35,6 @@ private void CompleteAcceptOperation(IntPtr acceptedFileDescriptor, Memory<byte>
             _acceptedFileDescriptor = acceptedFileDescriptor;
             if (socketError == SocketError.Success)
             {
-                Debug.Assert(socketAddress.Length > 0);
                 _acceptAddressBufferCount = socketAddress.Length;
             }
             else
@@ -348,9 +347,10 @@ private SocketError FinishOperationAccept(SocketAddress remoteSocketAddress)
             new ReadOnlySpan<byte>(_acceptBuffer, 0, _acceptAddressBufferCount).CopyTo(remoteSocketAddress.Buffer.Span);
             remoteSocketAddress.Size = _acceptAddressBufferCount;
 
+            // on macOS accept can sometimes return empty remote address even when it returns successfully.
             Socket acceptedSocket = _currentSocket!.CreateAcceptSocket(
                 SocketPal.CreateSocket(_acceptedFileDescriptor),
-                _currentSocket._rightEndPoint!.Create(remoteSocketAddress));
+                remoteSocketAddress.Size > 0 ? _currentSocket._rightEndPoint!.Create(remoteSocketAddress) : null);
             if (_acceptSocket is null)
             {
                 // Store the accepted socket

src/native/libs/System.Native/pal_networking.c

@@ -1660,6 +1660,11 @@ int32_t SystemNative_Connect(intptr_t socket, uint8_t* socketAddress, int32_t so
     return err == 0 ? Error_SUCCESS : SystemNative_ConvertErrorPlatformToPal(errno);
 }
 
+#if defined(__linux__) && !defined(TCP_FASTOPEN_CONNECT)
+// fixup if compiled against old Kernel headers.
+// Can be removed once we have at least 4.11
+#define TCP_FASTOPEN_CONNECT 30
+#endif
 int32_t SystemNative_Connectx(intptr_t socket, uint8_t* socketAddress, int32_t socketAddressLen, uint8_t* data, int32_t dataLen, int32_t tfo, int* sent)
 {
     if (socketAddress == NULL || socketAddressLen < 0 || sent == NULL)

src/tests/JIT/Directed/tls/TestTLSWithLoadedDlls.csproj

@@ -4,6 +4,8 @@
     <RequiresProcessIsolation>true</RequiresProcessIsolation>
     <ReferenceXUnitWrapperGenerator>false</ReferenceXUnitWrapperGenerator>
     <NativeAotIncompatible>true</NativeAotIncompatible>
+    <!-- Tracking issue: https://github.com/dotnet/runtime/issues/92129 -->
+    <CLRTestTargetUnsupported Condition="'$(TargetsAppleMobile)' == 'true'">true</CLRTestTargetUnsupported>
   </PropertyGroup>
   <PropertyGroup>
     <DebugType>PdbOnly</DebugType>