From c06f3c4760d49d69b28abca0d7530b47e627c021 Mon Sep 17 00:00:00 2001
From: Anton Firszov <Anton.Firszov@microsoft.com>
Date: Wed, 6 Jan 2021 13:22:48 +0100
Subject: [PATCH] Fix Socket.ReceiveFrom on Unix (#46151)

Fix a regression within the sync-over-async blocking path within the Unix ReceiveFrom implementation.
---
 .../src/System/Net/Sockets/SocketAsyncContext.Unix.cs                 | 1 +
 .../tests/FunctionalTests/SendReceive/SendReceive.cs                  | 1 +
 .../tests/FunctionalTests/SendReceive/SendReceiveNonParallel.cs       | 4 ++++
 .../System.Net.Sockets/tests/FunctionalTests/SocketTestHelper.cs      | 4 ++++
 4 files changed, 10 insertions(+)

diff --git a/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs b/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs
index 343c9c9..4202cdb 100644
--- a/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs
+++ b/src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketAsyncContext.Unix.cs
@@ -1505,6 +1505,7 @@ namespace System.Net.Sockets
             {
                 Buffer = buffer,
                 Flags = flags,
+                SetReceivedFlags = true,
                 SocketAddress = socketAddress,
                 SocketAddressLen = socketAddressLen,
             };
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs
index dfef96e..a96680a 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs
@@ -873,6 +873,7 @@ namespace System.Net.Sockets.Tests
                 var socket = new Socket(address.AddressFamily, SocketType.Dgram, ProtocolType.Udp);
                 if (address.IsIPv4MappedToIPv6) socket.DualMode = true;
                 socket.BindToAnonymousPort(address);
+                ConfigureNonBlocking(socket);
 
                 Task receiveTask = ReceiveAsync(socket, new ArraySegment<byte>(new byte[1]));
 
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceiveNonParallel.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceiveNonParallel.cs
index 02cb9a0..634d0f4 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceiveNonParallel.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceiveNonParallel.cs
@@ -40,6 +40,10 @@ namespace System.Net.Sockets.Tests
             using var left = useClone ? new Socket(origLeft.SafeHandle) : origLeft;
             using var right = useClone ? new Socket(origRight.SafeHandle) : origRight;
 
+            // Force non-blocking mode in ...SyncForceNonBlocking variants of the test: 
+            ConfigureNonBlocking(left);
+            ConfigureNonBlocking(right);
+
             var leftEndpoint = (IPEndPoint)left.LocalEndPoint;
             var rightEndpoint = (IPEndPoint)right.LocalEndPoint;
 
diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketTestHelper.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketTestHelper.cs
index 41fa116..b6ff517 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketTestHelper.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketTestHelper.cs
@@ -41,6 +41,7 @@ namespace System.Net.Sockets.Tests
         public virtual bool SupportsAcceptIntoExistingSocket => true;
         public virtual bool SupportsAcceptReceive => false;
         public virtual void Listen(Socket s, int backlog) { s.Listen(backlog); }
+        public virtual void ConfigureNonBlocking(Socket s) { }
     }
 
     public class SocketHelperArraySync : SocketHelperBase
@@ -91,6 +92,7 @@ namespace System.Net.Sockets.Tests
             s.Listen(backlog);
             s.ForceNonBlocking(true);
         }
+        public override void ConfigureNonBlocking(Socket s) => s.ForceNonBlocking(true);
     }
 
     public sealed class SocketHelperApm : SocketHelperBase
@@ -345,6 +347,7 @@ namespace System.Net.Sockets.Tests
         public bool SupportsAcceptIntoExistingSocket => _socketHelper.SupportsAcceptIntoExistingSocket;
         public bool SupportsAcceptReceive => _socketHelper.SupportsAcceptReceive;
         public void Listen(Socket s, int backlog) => _socketHelper.Listen(s, backlog);
+        public void ConfigureNonBlocking(Socket s) => _socketHelper.ConfigureNonBlocking(s);
     }
 
     public class SocketHelperSpanSync : SocketHelperArraySync
@@ -364,6 +367,7 @@ namespace System.Net.Sockets.Tests
             Task.Run(() => { s.ForceNonBlocking(true); Socket accepted = s.Accept(); accepted.ForceNonBlocking(true); return accepted; });
         public override Task ConnectAsync(Socket s, EndPoint endPoint) =>
             Task.Run(() => { s.ForceNonBlocking(true); s.Connect(endPoint); });
+        public override void ConfigureNonBlocking(Socket s) => s.ForceNonBlocking(true);
     }
 
     public sealed class SocketHelperMemoryArrayTask : SocketHelperTask
-- 
2.7.4