Merge pull request #897 from Unity-Technologies/proper-socket-error

Report the proper socket error (case 1012875)

Release notes:
Scripting: Provide the proper socket error when an IPv4 connection is refused.

Author: joshpeterson

mcs/class/System/System.Net.Sockets/Socket.cs

@@ -1160,7 +1160,19 @@ bool GetCheckedIPs (SocketAsyncEventArgs e, out IPAddress [] addresses)
 			// while skipping entries that do not match the address family
 			DnsEndPoint dep = e.RemoteEndPoint as DnsEndPoint;
 			if (dep != null) {
-				addresses = Dns.GetHostAddresses (dep.Host);
+				var possibleAddresses = Dns.GetHostAddresses (dep.Host);
+				var numberOfAddresses = 0;
+				int[] addressIndices = new int[possibleAddresses.Length];
+				for (var i = 0; i < possibleAddresses.Length; i++) {
+					if (possibleAddresses[i].AddressFamily == dep.AddressFamily) {
+						addressIndices[numberOfAddresses] = i;
+						numberOfAddresses++;
+					}
+				}
+				addresses = new IPAddress[numberOfAddresses];
+				for (var i = 0; i < numberOfAddresses; i++)
+					addresses[i] = possibleAddresses[addressIndices[i]];
+
 				return true;
 			} else {
 				e.ConnectByNameError = null;