Set UDP Client socket to disregard ICMP errors and forcibly disconnect.

Author: phalasz

ForgeUnity/Assets/BeardedManStudios/Scripts/Networking/Forge/Networking/CachedUdpClient.cs

@@ -21,10 +21,10 @@
 // distribute, sublicense, and/or sell copies of the Software, and to
 // permit persons to whom the Software is furnished to do so, subject to
 // the following conditions:
-// 
+//
 // The above copyright notice and this permission notice shall be
 // included in all copies or substantial portions of the Software.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
@@ -46,6 +46,16 @@ namespace BeardedManStudios.Forge.Networking
 {
 	public class CachedUdpClient : IDisposable
 	{
+		/// <summary>
+		/// Winsock ioctl code which will disable ICMP errors from being propagated to a UDP socket.
+		/// This can occur if a UDP packet is sent to a valid destination but there is no socket
+		/// registered to listen on the given port.
+		/// </summary>
+		/// http://msdn.microsoft.com/en-us/library/cc242275.aspx
+		/// http://msdn.microsoft.com/en-us/library/bb736550(VS.85).aspx
+		/// 0x9800000C == 2550136844 (uint) == -1744830452 (int) == 0x9800000C
+		const int SIO_UDP_CONNRESET = -1744830452;
+
 		public const char HOST_PORT_CHARACTER_SEPARATOR = '+';
 		private bool disposed = false;
 		private bool active = false;
@@ -140,6 +150,9 @@ private void InitSocket(EndPoint localEP)
 			if (localEP != null)
 				socket.Bind(localEP);
 
+			// set socket to disregard ICMP errors.
+			socket.IOControl((IOControlCode)SIO_UDP_CONNRESET, new byte[] { 0, 0, 0, 0 }, null);
+
 			recBuffer.SetSize(65536);
 		}