Add cache for Socket.LocalEndPoint #39313

CarnaViire · 2020-07-14T19:18:11Z

Added _localEndPoint field to cache LocalEndPoint value. ~~Introduced RightEndPoint property to encapsulate clearing _localEndPoint on _rightEndPoint change.~~ ~~Cached value is cleared on connect, error and disconnect.~~ Cached value is cleared on error and disconnect. If the value is a wildcard address, it is also cleared on connect and accept.

Fix #1482

ghost · 2020-07-14T19:18:17Z

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CarnaViire · 2020-07-16T18:10:28Z

/azp run runtime-libraries outerloop

azure-pipelines · 2020-07-16T18:10:43Z

Azure Pipelines successfully started running 1 pipeline(s).

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

CarnaViire · 2020-07-24T07:23:19Z

/azp run runtime-libraries outerloop

azure-pipelines · 2020-07-24T07:23:32Z

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karelz

LGTM, but I let @antonfirsov make the final ok ;)

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

antonfirsov · 2020-07-26T17:43:59Z

I'm concerned if we should maybe reset _localEndpoint to null in methods where we also reset _rightEndpoint:

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

Lines 2685 to 2712 in f8e92ec

    
           EndPoint? oldEndPoint = _rightEndPoint; 
        
           // Guarantee to call CheckAsyncCallOverlappedResult if we call SetUnamangedStructures with a cache in order to 
        
           // avoid a Socket leak in case of error. 
        
           SocketError errorCode = SocketError.SocketError; 
        
           try 
        
           { 
        
               if (_rightEndPoint == null) 
        
               { 
        
                   _rightEndPoint = endPointSnapshot; 
        
               } 
        
               errorCode = SocketPal.SendToAsync(_handle, buffer, offset, size, socketFlags, socketAddress, asyncResult); 
        
               if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"SendToAsync returns:{errorCode} size:{size} returning AsyncResult:{asyncResult}"); 
        
           } 
        
           catch (ObjectDisposedException) 
        
           { 
        
               _rightEndPoint = oldEndPoint; 
        
               throw; 
        
           } 
        
           // Throw an appropriate SocketException if the native call fails synchronously. 
        
           if (!CheckErrorAndUpdateStatus(errorCode)) 
        
           { 
        
               UpdateSendSocketErrorForDisposed(ref errorCode); 
        
               // Update the internal state of this socket according to the error before throwing. 
        
               _rightEndPoint = oldEndPoint;

If I'm not missing anything there will be no user callback querying LocalEndpoint in case of failure, however we may end up adding internal code doing so in the future, for example in a tracing call like this:

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

Line 1083 in f8e92ec

    
           if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"SRC:{LocalEndPoint}");

Such a call may enforce caching a wrong value for LocalEndpoint permanently, on the other hand it's probably very unlikely we do such a thing by accident. I wonder if it makes sense to add tests to ensure such failing async methods will not alter the sockets internal state in an unwanted way.

@tmds maybe you have some thoughts on this?

CarnaViire · 2020-07-28T17:44:08Z

@antonfirsov Here is a list of all changes of _rightEndPoint that I have found in the code (sorry for the long list, I would put it under cut if I knew how)

setting to new value

1.1. in constructor
Socket.cs(165:25): _rightEndPoint = new IPEndPoint(
Socket.cs(173:25): _rightEndPoint = new IPEndPoint(
Socket.cs(180:25): _rightEndPoint = new UnixDomainSocketEndPoint(IPEndPointExtensions.GetNetSocketAddress(socketAddress));
Socket.Windows.cs(69:17): _rightEndPoint = ep.Create(socketAddress);

1.2. after non-blocking connect
[LocalEndPoint] Socket.cs(319:21): _rightEndPoint = _nonBlockingConnectRightEndPoint;
[RemoteEndPoint] Socket.cs(361:25): _rightEndPoint = _nonBlockingConnectRightEndPoint;
[Connected] Socket.cs(472:21): _rightEndPoint = _nonBlockingConnectRightEndPoint;

1.3. if it was null before
[DoBind] Socket.cs(834:17): _rightEndPoint = endPointSnapshot;
[SendTo] Socket.cs(1329:17): _rightEndPoint = remoteEP;
[ReceiveMessageFrom] Socket.cs(1566:21): _rightEndPoint = endPointSnapshot;
[ReceiveFrom] Socket.cs(1650:21): _rightEndPoint = endPointSnapshot;
[DoBeginSendTo] Socket.cs(2694:21): _rightEndPoint = endPointSnapshot;
[BeginReceiveMessageFrom] Socket.cs(3059:21): _rightEndPoint = remoteEP;
[DoBeginReceiveFrom] Socket.cs(3276:21): _rightEndPoint = endPointSnapshot;
[ConnectAsync] Socket.cs(3677:21): _rightEndPoint = endPointSnapshot;
[SendToAsync] Socket.cs(4019:17): _rightEndPoint = endPointSnapshot;
[DoConnect] Socket.cs(4155:17): _rightEndPoint = endPointSnapshot;
[BeginConnectEx] Socket.cs(4536:17): _rightEndPoint = endPointSnapshot;

1.4. on inheriting other socket state
[UpdateAcceptSocket] Socket.cs(4784:20): socket._rightEndPoint = _rightEndPoint;
setting to previous value - on some error

2.1. on ObjectDisposedException, throwing later
[DoBeginSendTo] Socket.cs(2703:17): _rightEndPoint = oldEndPoint;
[BeginReceiveMessageFrom] Socket.cs(3081:17): _rightEndPoint = oldEndPoint;
[DoBeginReceiveFrom] Socket.cs(3285:17): _rightEndPoint = oldEndPoint;

2.2. on any exception, throwing later
[ConnectAsync] Socket.cs(3700:21): _rightEndPoint = oldEndPoint;
[BeginConnectEx] Socket.cs(4547:17): _rightEndPoint = oldEndPoint;

2.3. on false CheckErrorAndUpdateStatus, throwing later
[DoBeginSendTo] Socket.cs(2712:17): _rightEndPoint = oldEndPoint;
[BeginReceiveMessageFrom] Socket.cs(3090:17): _rightEndPoint = oldEndPoint;
[DoBeginReceiveFrom] Socket.cs(3294:17): _rightEndPoint = oldEndPoint;
[BeginConnectEx] Socket.cs(4563:17): _rightEndPoint = oldEndPoint;

2.4. on false CheckErrorAndUpdateStatus, NO throwing
[SendToAsync] Socket.cs(4037:17): _rightEndPoint = oldEndPoint;
setting to null - on some error

3.1. on any exception, throwing later
[SendToAsync] Socket.cs(4029:17): _rightEndPoint = null;

You suggest to clear _localEndPoint on the reset of _rightEndPoint, which are items 2. and 3. on the list. If we look at subitems of item 1., we can see that most of them are if _rightEndPoint was null before or in the constructor, which means if we clear _localEndPoint at this time we won't actually change anything. And a change of _rightEndPoint after non-blocking connect will only happen once I believe.

What I am trying to say is if we want to clear _localEndPoint on the reset of _rightEndPoint, maybe we could actually return to my original proposal of clearing _localEndPoint on every _rightEndPoint change? The only place where it might possibly unnesessary clear some cached value is this non-blocking connect part (item 1.2.) and we might use _rightEndPoint there instead of new property RightEndPoint specifically in this case.

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

azure-pipelines · 2020-08-18T16:45:39Z

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CarnaViire · 2020-08-19T04:56:39Z

/azp run runtime-libraries outerloop

azure-pipelines · 2020-08-19T04:56:53Z

Azure Pipelines successfully started running 1 pipeline(s).

CarnaViire · 2020-08-25T16:13:27Z

So the behavior with wildcard addresses is as follows.

If a TCP server socket (listener socket) was bound to a wildcard address, then the accept socket created with accept will be assigned with a specific address based on what interface a client socket connected to. That means we can't copy cached listener's local endpoint if it is wildcard. However, if the listener was bound to a specific address, we can copy that to the accept socket freely.
If a TCP client socket was bound to a wildcard address, then it will be assigned with a specific address after connect. That means we should clear the client socket's cached local endpoint if it is wildcard.
If an UDP socket was bound to a wildcard address, it stays as wildcard even after sendto and other calls.

I added clearing of cached wildcard local endpoints on connect and accept with clarifying comments. Also added tests that illustrate this behavior.

cc @geoffkizer @antonfirsov

CarnaViire · 2020-08-25T18:31:10Z

/azp run runtime-libraries outerloop

azure-pipelines · 2020-08-25T18:31:23Z

Azure Pipelines successfully started running 1 pipeline(s).

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

CarnaViire · 2020-08-26T10:09:08Z

/azp run runtime-libraries outerloop

azure-pipelines · 2020-08-26T10:09:21Z

Azure Pipelines successfully started running 1 pipeline(s).

CarnaViire · 2020-08-27T09:34:01Z

Outerloop test failures are #40926 and #41381

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

antonfirsov

We need to make sure all independent implementations are covered in the tests, otherwise looks good now.

antonfirsov · 2020-08-28T17:20:40Z

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

+        [Fact]
+        public void UdpSocket_ClientNotBound_LocalEPBecomesWildcardOnSendTo()
+        {
+            using (Socket server = CreateUdpSocket())
+            using (Socket client = CreateUdpSocket())
+            {
+                int serverPort = server.BindToAnonymousPort(Wildcard);
+
+                Assert.Null(client.LocalEndPoint); // null before sendto
+
+                var sendToEP = new IPEndPoint(Loopback, serverPort);
+
+                client.SendTo(new byte[] { 1, 2, 3 }, sendToEP);
+
+                Assert.Equal(Wildcard, GetLocalEPAddress(client)); // wildcard after sendto
+
+                byte[] buf = new byte[3];
+                EndPoint receiveFromEP = new IPEndPoint(Wildcard, 0);
+                server.ReceiveFrom(buf, ref receiveFromEP);
+
+                Assert.Equal(new byte[] { 1, 2, 3 }, buf);
+            }
+        }
+
+        [Fact]
+        public void UdpSocket_ClientNotBound_LocalEPBecomesWildcardOnAsyncSendTo()
+        {
+            using (Socket server = CreateUdpSocket())
+            using (Socket client = CreateUdpSocket())
+            {
+                int serverPort = server.BindToAnonymousPort(Wildcard);
+
+                Assert.Null(client.LocalEndPoint); // null before async WSASendTo
+
+                var sendToEP = new IPEndPoint(Loopback, serverPort);
+
+                IAsyncResult sendToResult = client.BeginSendTo(new byte[] { 4, 5, 6 }, 0, 3, SocketFlags.None, sendToEP, null, null);
+                sendToResult.AsyncWaitHandle.WaitOne();
+                client.EndSendTo(sendToResult);
+
+                Assert.Equal(Wildcard, GetLocalEPAddress(client)); // wildcard after async WSASendTo
+
+                byte[] buf = new byte[3];
+                EndPoint receiveFromEP = new IPEndPoint(Wildcard, 0);
+                server.ReceiveFrom(buf, ref receiveFromEP);
+
+                Assert.Equal(new byte[] { 4, 5, 6 }, buf);
+            }
+        }


These 2 tests seem to test the same thing for two different connect implementations. I suggest dedupe their code and also cover the remaining ones: ConnectAsync(SocketAsyncEventArgs) and SocketTaskExtensions.ConnectAsync(this Socket, ....). For this the best would be to utilize SocketTestHelperBase<T>.

Rewrote the tests, please check that I understood you correctly :)

CarnaViire added 3 commits July 14, 2020 16:06

Add cache for LocalEndPoint

2e977ea

Add RightEndPoint property, clear _localEndPoint in RightEndPoint setter

579f788

Merge remote-tracking branch 'upstream/master' into issue-1482

bc08140

CarnaViire requested a review from a team July 14, 2020 19:18

Dotnet-GitSync-Bot added the area-System.Net.Sockets label Jul 14, 2020

antonfirsov reviewed Jul 16, 2020

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src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.cs Outdated Show resolved Hide resolved

src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.cs Outdated Show resolved Hide resolved

CarnaViire marked this pull request as draft July 20, 2020 08:23

CarnaViire added 5 commits July 20, 2020 14:07

Merge remote-tracking branch 'upstream/master' into issue-1482

c68e608

Merge remote-tracking branch 'upstream/master' into issue-1482

3771a6d

Merge remote-tracking branch 'upstream/master' into issue-1482

d953b0f

Roll back property changes

f0a5ec9

Fix _nonBlockingConnectRightEndPoint

999d596

CarnaViire force-pushed the issue-1482 branch from 524b580 to 999d596 Compare July 23, 2020 15:20

CarnaViire marked this pull request as ready for review July 23, 2020 15:21

jaredpar mentioned this pull request Jul 24, 2020

OSX machines are de-provisioned during CI / PR runs leading to failures #34472

Closed

karelz approved these changes Jul 26, 2020

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src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.cs Show resolved Hide resolved

CarnaViire added 4 commits July 31, 2020 14:10

Merge branch 'master' into issue-1482

79b7153

Add clear on error

d715a31

Add clear on connect and tests

c3eb4ec

Add caching test

324e060

antonfirsov reviewed Aug 6, 2020

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src/libraries/System.Net.Sockets/tests/FunctionalTests/LocalEndPointTest.cs Outdated Show resolved Hide resolved

CarnaViire added 2 commits August 11, 2020 15:57

Use BindToAnonymousPort

283f11b

Merge remote-tracking branch 'upstream/master' into issue-1482

0a6a26a

Assign _localEndPoint from the listener

ec8e54e

CarnaViire marked this pull request as draft August 21, 2020 19:44

CarnaViire added 5 commits August 24, 2020 12:37

tmp commit to check on mac

3d9385b

tmp

4e183ed

Merge remote-tracking branch 'upstream/master' into issue-1482

e626406

Merge branch 'master' into issue-1482

74988a2

Fix _localEndPoint clearing on mac

eeb057d

CarnaViire marked this pull request as ready for review August 25, 2020 16:13

antonfirsov reviewed Aug 25, 2020

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CarnaViire added 2 commits August 26, 2020 12:57

Inline wildcard addresses

85de50d

Merge remote-tracking branch 'upstream/master' into issue-1482

b86cc93

CarnaViire mentioned this pull request Aug 26, 2020

Test failure: System.Net.Http.Functional.Tests.SocketsHttpHandler_HttpClientHandler_ServerCertificates_Test.UseCallback_BadCertificate_ExpectedPolicyErrors #41402

Closed

antonfirsov reviewed Aug 27, 2020

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PR fixes

cbaed88

antonfirsov approved these changes Aug 28, 2020

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Rewrite tests with SocketTestHelperBase

d0fa759

antonfirsov approved these changes Sep 2, 2020

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CarnaViire merged commit e04ad64 into dotnet:master Sep 2, 2020

CarnaViire deleted the issue-1482 branch September 2, 2020 13:52

ghost locked as resolved and limited conversation to collaborators Dec 8, 2020

karelz added this to the 6.0.0 milestone Jan 26, 2021

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Add cache for Socket.LocalEndPoint #39313

Add cache for Socket.LocalEndPoint #39313

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Add cache for Socket.LocalEndPoint #39313

Add cache for Socket.LocalEndPoint #39313

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