Fix RHEL7 socket dispose hang, and extend coverage

src/libraries/Common/tests/System/Net/Sockets/SocketTestExtensions.cs

@@ -38,14 +38,21 @@ public static void ForceNonBlocking(this Socket socket, bool force)
             }
         }
 
-        public static (Socket, Socket) CreateConnectedSocketPair()
+        public static (Socket client, Socket server) CreateConnectedSocketPair() => CreateConnectedSocketPair(IPAddress.Loopback, false);
+
+        public static (Socket client, Socket server) CreateConnectedSocketPair(IPAddress serverAddress, bool dualModeClient)
         {
-            using Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
-            listener.Bind(new IPEndPoint(IPAddress.Loopback, 0));
+            using Socket listener = new Socket(serverAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
+            listener.Bind(new IPEndPoint(serverAddress, 0));
             listener.Listen(1);
 
-            Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
-            client.Connect(listener.LocalEndPoint);
+            IPEndPoint connectTo = (IPEndPoint)listener.LocalEndPoint;
+            if (dualModeClient) connectTo = new IPEndPoint(connectTo.Address.MapToIPv6(), connectTo.Port);
+
+
+            Socket client = new Socket(connectTo.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
+            if (dualModeClient) client.DualMode = true;
+            client.Connect(connectTo);
             Socket server = listener.Accept();
 
             return (client, server);

src/libraries/Native/Unix/System.Native/pal_networking.c

@@ -3085,6 +3085,11 @@ int32_t SystemNative_Disconnect(intptr_t socket)
     addr.sa_family = AF_UNSPEC;
 
     err = connect(fd, &addr, sizeof(addr));
+    if (err != 0) 
+    {
+        // On some older kernels connect(AF_UNSPEC) may fail. Fall back to shutdown in these cases:
+        err = shutdown(fd, SHUT_RDWR);
+    } 
 #elif HAVE_DISCONNECTX
     // disconnectx causes a FIN close on OSX. It's the best we can do.
     err = disconnectx(fd, SAE_ASSOCID_ANY, SAE_CONNID_ANY);

src/libraries/System.Net.Sockets/tests/FunctionalTests/Accept.cs

@@ -289,16 +289,26 @@ public async Task AcceptAsync_MultipleAcceptsThenDispose_AcceptsThrowAfterDispos
             }
         }
 
-        [Fact]
-        public async Task AcceptGetsCanceledByDispose()
+        public static readonly TheoryData<IPAddress> AcceptGetsCanceledByDispose_Data = new TheoryData<IPAddress>
+        {
+            { IPAddress.Loopback },
+            { IPAddress.IPv6Loopback },
+            { IPAddress.Loopback.MapToIPv6() }
+        };
+
+        [Theory]
+        [MemberData(nameof(AcceptGetsCanceledByDispose_Data))]
+        public async Task AcceptGetsCanceledByDispose(IPAddress loopback)
         {
             // We try this a couple of times to deal with a timing race: if the Dispose happens
             // before the operation is started, we won't see a SocketException.
             int msDelay = 100;
-            await RetryHelper.ExecuteAsync(async () =>
+            int retries = 10;
+            while (true)
             {
-                var listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
-                listener.Bind(new IPEndPoint(IPAddress.Loopback, 0));
+                var listener = new Socket(loopback.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
+                if (loopback.IsIPv4MappedToIPv6) listener.DualMode = true;
+                listener.Bind(new IPEndPoint(loopback, 0));
                 listener.Listen(1);
 
                 Task acceptTask = AcceptAsync(listener);
@@ -330,20 +340,33 @@ await RetryHelper.ExecuteAsync(async () =>
                     disposedException = true;
                 }
 
-                if (UsesApm)
-                {
-                    Assert.Null(localSocketError);
-                    Assert.True(disposedException);
-                }
-                else if (UsesSync)
+                try
                 {
-                    Assert.Equal(SocketError.Interrupted, localSocketError);
+                    if (UsesApm)
+                    {
+                        Assert.Null(localSocketError);
+                        Assert.True(disposedException);
+                    }
+                    else if (UsesSync)
+                    {
+                        Assert.Equal(SocketError.Interrupted, localSocketError);
+                    }
+                    else
+                    {
+                        Assert.Equal(SocketError.OperationAborted, localSocketError);
+                    }
+                    break;
                 }
-                else
+                catch
                 {
-                    Assert.Equal(SocketError.OperationAborted, localSocketError);
+                    if (retries-- > 0)
+                    {
+                        continue;
+                    }
+
+                    throw;
                 }
-            }, maxAttempts: 10);
+            }
         }
 
         [Fact]

src/libraries/System.Net.Sockets/tests/FunctionalTests/Connect.cs

@@ -120,18 +120,29 @@ public async Task Connect_AfterDisconnect_Fails()
             }
         }
 
-        [Fact]
+        public static readonly TheoryData<IPAddress> ConnectGetsCanceledByDispose_Data = new TheoryData<IPAddress>
+        {
+            { IPAddress.Parse("1.1.1.1") },
+            // TODO: Figure out how to test this with vanilla IPV6
+            { IPAddress.Parse("1.1.1.1").MapToIPv6() },
+        };
+
+        [OuterLoop("Uses external server")]
+        [Theory]
+        [MemberData(nameof(ConnectGetsCanceledByDispose_Data))]
         [PlatformSpecific(~(TestPlatforms.OSX | TestPlatforms.FreeBSD))] // Not supported on BSD like OSes.
-        public async Task ConnectGetsCanceledByDispose()
+        public async Task ConnectGetsCanceledByDispose(IPAddress address)
         {
             // We try this a couple of times to deal with a timing race: if the Dispose happens
             // before the operation is started, we won't see a SocketException.
             int msDelay = 100;
-            await RetryHelper.ExecuteAsync(async () =>
+            int retries = 10;
+            while (true)
             {
-                var client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+                var client = new Socket(address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
+                if (address.IsIPv4MappedToIPv6) client.DualMode = true;
 
-                Task connectTask = ConnectAsync(client, new IPEndPoint(IPAddress.Parse("1.1.1.1"), 23));
+                Task connectTask = ConnectAsync(client, new IPEndPoint(address, 23));
 
                 // Wait a little so the operation is started.
                 await Task.Delay(msDelay);
@@ -153,30 +164,43 @@ await RetryHelper.ExecuteAsync(async () =>
                 }
                 catch (SocketException se)
                 {
-                    // On connection timeout, retry.
-                    Assert.NotEqual(SocketError.TimedOut, se.SocketErrorCode);
-
                     localSocketError = se.SocketErrorCode;
                 }
                 catch (ObjectDisposedException)
                 {
                     disposedException = true;
                 }
 
-                if (UsesApm)
-                {
-                    Assert.Null(localSocketError);
-                    Assert.True(disposedException);
-                }
-                else if (UsesSync)
+                try
                 {
-                    Assert.Equal(SocketError.NotSocket, localSocketError);
+                    // On connection timeout, retry.
+                    Assert.NotEqual(SocketError.TimedOut, localSocketError);
+
+                    if (UsesApm)
+                    {
+                        Assert.Null(localSocketError);
+                        Assert.True(disposedException);
+                    }
+                    else if (UsesSync)
+                    {
+                        Assert.Equal(SocketError.NotSocket, localSocketError);
+                    }
+                    else
+                    {
+                        Assert.Equal(SocketError.OperationAborted, localSocketError);
+                    }
+                    break;
                 }
-                else
+                catch
                 {
-                    Assert.Equal(SocketError.OperationAborted, localSocketError);
+                    if (retries-- > 0)
+                    {
+                        continue;
+                    }
+
+                    throw;
                 }
-            }, maxAttempts: 10);
+            }
         }
     }
 

src/libraries/System.Net.Sockets/tests/FunctionalTests/InlineCompletions.Unix.cs

@@ -31,8 +31,8 @@ public void InlineSocketContinuations()
                 await new SendReceiveEap(null).SendRecv_Stream_TCP(IPAddress.Loopback, useMultipleBuffers: false);
                 await new SendReceiveEap(null).SendRecv_Stream_TCP_MultipleConcurrentReceives(IPAddress.Loopback, useMultipleBuffers: false);
                 await new SendReceiveEap(null).SendRecv_Stream_TCP_MultipleConcurrentSends(IPAddress.Loopback, useMultipleBuffers: false);
-                await new SendReceiveEap(null).TcpReceiveSendGetsCanceledByDispose(receiveOrSend: true);
-                await new SendReceiveEap(null).TcpReceiveSendGetsCanceledByDispose(receiveOrSend: false);
+                await new SendReceiveEap(null).TcpReceiveSendGetsCanceledByDispose(receiveOrSend: true, serverAddress: IPAddress.Loopback, dualModeClient: false);
+                await new SendReceiveEap(null).TcpReceiveSendGetsCanceledByDispose(receiveOrSend: false, serverAddress: IPAddress.Loopback, dualModeClient: false);
             }, options).Dispose();
         }
     }

src/libraries/System.Net.Sockets/tests/FunctionalTests/SendFile.cs

@@ -288,7 +288,8 @@ public async Task SyncSendFileGetsCanceledByDispose()
             // before the operation is started, the peer won't see a ConnectionReset SocketException and we won't
             // see a SocketException either.
             int msDelay = 100;
-            await RetryHelper.ExecuteAsync(async () =>
+            int retries = 10;
+            while (true)
             {
                 (Socket socket1, Socket socket2) = SocketTestExtensions.CreateConnectedSocketPair();
                 using (socket2)
@@ -328,34 +329,48 @@ await RetryHelper.ExecuteAsync(async () =>
                     }
                     catch (ObjectDisposedException)
                     { }
-                    Assert.Equal(SocketError.ConnectionAborted, localSocketError);
 
-                    // On OSX, we're unable to unblock the on-going socket operations and
-                    // perform an abortive close.
-                    if (!PlatformDetection.IsOSXLike)
+                    try
                     {
-                        SocketError? peerSocketError = null;
-                        var receiveBuffer = new byte[4096];
-                        while (true)
+                        Assert.Equal(SocketError.ConnectionAborted, localSocketError);
+
+                        // On OSX, we're unable to unblock the on-going socket operations and
+                        // perform an abortive close.
+                        if (!PlatformDetection.IsOSXLike)
                         {
-                            try
+                            SocketError? peerSocketError = null;
+                            var receiveBuffer = new byte[4096];
+                            while (true)
                             {
-                                int received = socket2.Receive(receiveBuffer);
-                                if (received == 0)
+                                try
                                 {
+                                    int received = socket2.Receive(receiveBuffer);
+                                    if (received == 0)
+                                    {
+                                        break;
+                                    }
+                                }
+                                catch (SocketException se)
+                                {
+                                    peerSocketError = se.SocketErrorCode;
                                     break;
                                 }
                             }
-                            catch (SocketException se)
-                            {
-                                peerSocketError = se.SocketErrorCode;
-                                break;
-                            }
+                            Assert.Equal(SocketError.ConnectionReset, peerSocketError);
                         }
-                        Assert.Equal(SocketError.ConnectionReset, peerSocketError);
+                        break;
+                    }
+                    catch
+                    {
+                        if (retries-- > 0)
+                        {
+                            continue;
+                        }
+
+                        throw;
                     }
                 }
-            }, maxAttempts: 10);
+            }
         }
 
         [OuterLoop]