Merge pull request #61 from rdavisau/fix-odd-udp-issue

prevent exception if UdpClient receives an ICMP unreachable packet
rdavisau · Jan 10, 2016 · 34f7b1b · 34f7b1b
2 parents 108df61 + 0bbfed8
commit 34f7b1b
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Showing 4 changed files with 17 additions and 2 deletions.
diff --git a/Sockets/Sockets.Implementation.NET/UdpSocketBase.cs b/Sockets/Sockets.Implementation.NET/UdpSocketBase.cs
@@ -118,7 +118,18 @@ protected Task SendToAsync(byte[] data, int length, string address, int port)
                 .SendAsync(data, length, address, port)
                 .WrapNativeSocketExceptions();
         }
-
+
+        protected void ProtectAgainstICMPUnreachable(UdpClient udpClient)
+        {
+            // this should be called whenever the backing client is recreated.
+            // it prevents a strange class of errors, some discussion at
+            // http://stackoverflow.com/questions/7201862/an-existing-connection-was-forcibly-closed-by-the-remote-host
+
+            uint IOC_IN = 0x80000000;
+            uint IOC_VENDOR = 0x18000000;
+            uint SIO_UDP_CONNRESET = IOC_IN | IOC_VENDOR | 12;
+            udpClient.Client.IOControl((int)SIO_UDP_CONNRESET, new[] { Convert.ToByte(false) }, null);
+        }
 
         /// <summary>
         /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

diff --git a/Sockets/Sockets.Implementation.NET/UdpSocketClient.cs b/Sockets/Sockets.Implementation.NET/UdpSocketClient.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Net.Sockets;
 using System.Threading;
 using System.Threading.Tasks;
@@ -30,8 +31,8 @@ public UdpSocketClient()
                 _backingUdpClient = new UdpClient
                 {
                     EnableBroadcast = true
-
                 };
+                ProtectAgainstICMPUnreachable(_backingUdpClient);
             }
             catch (PlatformSocketException ex)
             {

diff --git a/Sockets/Sockets.Implementation.NET/UdpSocketMulticastClient.cs b/Sockets/Sockets.Implementation.NET/UdpSocketMulticastClient.cs
@@ -47,6 +47,7 @@ public async Task JoinMulticastGroupAsync(string multicastAddress, int port, ICo
                 {
                     EnableBroadcast = true
                 };
+                ProtectAgainstICMPUnreachable(_backingUdpClient);
             }
             catch (PlatformSocketException ex)
             {

diff --git a/Sockets/Sockets.Implementation.NET/UdpSocketReceiver.cs b/Sockets/Sockets.Implementation.NET/UdpSocketReceiver.cs
@@ -41,6 +41,7 @@ public Task StartListeningAsync(int port = 0, ICommsInterface listenOn = null)
                     {
                         EnableBroadcast = true
                     };
+                    ProtectAgainstICMPUnreachable(_backingUdpClient);
 
                     RunMessageReceiver(_messageCanceller.Token);
                 })
@@ -91,6 +92,7 @@ public Task StopListeningAsync()
                 try
                 {
                     _backingUdpClient = new UdpClient { EnableBroadcast = true };
+                    ProtectAgainstICMPUnreachable(_backingUdpClient);
                 }
                 catch (PlatformSocketException ex)
                 {