NetIncomingMessage.Clone added

Attempt to handle connection reset correctly when sending

Lidgren.Network/NetConnection.cs

@@ -207,7 +207,16 @@ namespace Lidgren.Network
 					if (ptr > 0 && (ptr + NetPeer.kMaxPacketHeaderSize + msgPayloadLength) > mtu)
 					{
 						// send packet and start new packet
-						m_owner.SendPacket(ptr, m_remoteEndpoint, numIncludedMessages);
+						bool connectionReset;
+						m_owner.SendPacket(ptr, m_remoteEndpoint, numIncludedMessages, out connectionReset);
+						if (connectionReset)
+						{
+							// ouch! can't sent any more; lets disconnect
+							Disconnect(NetConstants.ConnResetMessage);
+							ptr = 0;
+							numIncludedMessages = 0;
+							break;
+						}
 						m_statistics.PacketSent(ptr, numIncludedMessages);
 						numIncludedMessages = 0;
 						m_throttleDebt += ptr;
@@ -247,10 +256,19 @@ namespace Lidgren.Network
 
 				if (ptr > 0)
 				{
-					m_owner.SendPacket(ptr, m_remoteEndpoint, numIncludedMessages);
+					bool connectionReset;
-					m_statistics.PacketSent(ptr, numIncludedMessages);
+					m_owner.SendPacket(ptr, m_remoteEndpoint, numIncludedMessages, out connectionReset);
-					numIncludedMessages = 0;
+					if (connectionReset)
-					m_throttleDebt += ptr;
+					{
+						// ouch! can't sent any more; lets disconnect
+						Disconnect(NetConstants.ConnResetMessage);
+					}
+					else
+					{
+						m_statistics.PacketSent(ptr, numIncludedMessages);
+						numIncludedMessages = 0;
+						m_throttleDebt += ptr;
+					}
 				}
 			}
 		}

Lidgren.Network/NetConstants.cs

@@ -40,5 +40,7 @@ namespace Lidgren.Network
 		/// Number of bytes added when message is really a fragment
 		/// </summary>
 		internal const int FragmentHeaderSize = 6;
+
+		internal const string ConnResetMessage = "Connection was reset by remote host";
 	}
 }

Lidgren.Network/NetEncryption.cs

@@ -227,14 +227,73 @@ namespace Lidgren.Network
 
 			string one = NetUtility.ToHexString(A);
 			string two = NetUtility.ToHexString(B);
-			string compound = one + two.PadLeft(one.Length, '0');
+			string compound = one.PadLeft(64, '0') + two.PadLeft(64, '0');
 			byte[] cc = NetUtility.ToByteArray(compound);
+
 			return NetSha.Hash(cc);
+
+			//byte[] res = NetSha.Hash(cc);
+			//var resbig = new BigInteger(res);
+			//return BigInteger.Modulus(resbig, N).GetBytes();
+
+			/*
+			 * 
+ * SRP-3: u = first 32 bits (MSB) of SHA-1(B)
+ * SRP-6(a): u = SHA-1(A || B)
+function srp_compute_u(Nv, av, bv) {
+  var ahex;
+  var bhex = String(bigInt2radix(bv, 16));
+  var hashin = "";
+  var utmp;
+  var nlen;
+  if(proto != "3") {
+    ahex = String(bigInt2radix(av, 16));
+    if(proto == "6") {
+      if((ahex.length & 1) == 0) {
+        hashin += ahex;
+      }
+      else {
+        hashin += "0" + ahex;
+      }
+    }
+    else { // 6a requires left-padding
+      nlen = 2 * ((Nv.bitLength() + 7) >> 3);
+      hashin += nzero(nlen - ahex.length) + ahex;
+    }
+  }
+  if(proto == "3" || proto == "6") {
+    if((bhex.length & 1) == 0) {
+      hashin += bhex;
+    }
+    else {
+      hashin += "0" + bhex;
+    }
+  }
+  else { // 6a requires left-padding; nlen already set above 
+    hashin += nzero(nlen - bhex.length) + bhex;
+  }
+  if(proto == "3") {
+    utmp = parseBigInt(calcSHA1Hex(hashin).substr(0, 8), 16);
+  }
+  else {
+    utmp = parseBigInt(calcSHA1Hex(hashin), 16);
+  }
+  if(utmp.compareTo(Nv) < 0) {
+    return utmp;
+  }
+  else {
+    return utmp.mod(Nv.subtract(one));
+  }
+}
+
+
+			*/
+
 		}
 
 		/*
-		public static byte[] ComputeClientToken(byte[] serverChallenge, byte[] x, byte[] u
+		public static byte[] ComputeClientToken(byte[] serverChallenge, byte[] x, byte[] u)
-
+		{
 
 		// S = (B - kg^x) ^ (a + ux) (mod N)
 function srp_compute_client_S(BB, xx, uu, aa, kk) {

Lidgren.Network/NetIncomingMessage.cs

@@ -130,6 +130,28 @@ namespace Lidgren.Network
 			m_data = result;
 		}
 
+		public NetIncomingMessage Clone()
+		{
+			NetIncomingMessage retval = new NetIncomingMessage();
+
+			// copy content
+			retval.m_data = new byte[LengthBytes];
+			Buffer.BlockCopy(m_data, 0, retval.m_data, 0, LengthBytes);
+
+			retval.m_bitLength = m_bitLength;
+			retval.m_messageType = m_messageType;
+			retval.m_sequenceNumber = m_sequenceNumber;
+			retval.m_status = m_status;
+			retval.m_incomingType = m_incomingType;
+			retval.m_senderEndpoint = m_senderEndpoint;
+			retval.m_senderConnection = m_senderConnection;
+			retval.m_fragmentationInfo = m_fragmentationInfo;
+			retval.m_bitLength = m_bitLength;
+			retval.m_bitLength = m_bitLength;
+
+			return retval;
+		}
+
 		public override string ToString()
 		{
 			return String.Format("[NetIncomingMessage {0}, {1}|{2}, {3} bits]",

Lidgren.Network/NetPeer.Internal.cs

@@ -230,6 +230,7 @@ namespace Lidgren.Network
 				//
 
 				int ptr = um.Encode(now, m_sendBuffer, 0, null);
+				bool connectionReset = false;
 
 				if (recipient.Address.Equals(IPAddress.Broadcast))
 				{
@@ -237,7 +238,7 @@ namespace Lidgren.Network
 					try
 					{
 						m_socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, true);
-						SendPacket(ptr, recipient, 1);
+						SendPacket(ptr, recipient, 1, out connectionReset);
 					}
 					finally
 					{
@@ -247,8 +248,11 @@ namespace Lidgren.Network
 				else
 				{
 					// send normally
-					SendPacket(ptr, recipient, 1);
+					SendPacket(ptr, recipient, 1, out connectionReset);
 				}
+
+				if (connectionReset)
+					LogWarning(NetConstants.ConnResetMessage);
 			}
 
 			// check if we need to reduce the recycled pool
@@ -276,9 +280,9 @@ namespace Lidgren.Network
 				catch (SocketException sx)
 				{
 					// no good response to this yet
-					if (sx.ErrorCode == 10054)
+					if (sx.SocketErrorCode == SocketError.ConnectionReset)
 					{
-						// connection reset by peer, aka forcibly closed
+						// connection reset by peer, aka connection forcibly closed aka "ICMP port unreachable" 
 						// we should shut down the connection; but m_senderRemote seemingly cannot be trusted, so which connection should we shut down?!
 						//LogWarning("Connection reset by peer, seemingly from " + m_senderRemote);
 						return;
@@ -288,7 +292,7 @@ namespace Lidgren.Network
 					return;
 				}
 
-				if (bytesReceived < 1)
+				if (bytesReceived < NetPeer.kMinPacketHeaderSize)
 					return;
 
 				// renew current time; we might have waited in Poll
@@ -584,9 +588,13 @@ namespace Lidgren.Network
 			int len = msg.Encode(now, m_sendBuffer, 0, conn);
 			Interlocked.Decrement(ref msg.m_inQueueCount);
 
-			SendPacket(len, conn.m_remoteEndpoint, 1);
+			bool connectionReset;
+			SendPacket(len, conn.m_remoteEndpoint, 1, out connectionReset);
 
 			Recycle(msg);
+
+			if (connectionReset)
+				LogWarning("Connection was reset; remote host is not listening");
 		}
 	}
 }

Lidgren.Network/NetPeer.LatencySimulation.cs

@@ -37,8 +37,10 @@ namespace Lidgren.Network
 			public IPEndPoint Target;
 		}
 
-		internal void SendPacket(int numBytes, IPEndPoint target, int numMessages)
+		internal void SendPacket(int numBytes, IPEndPoint target, int numMessages, out bool connectionReset)
 		{
+			connectionReset = false;
+
 			// simulate loss
 			float loss = m_configuration.m_loss;
 			if (loss > 0.0f)
@@ -59,7 +61,7 @@ namespace Lidgren.Network
 			{
 				// no latency simulation
 				//LogVerbose("Sending packet " + numBytes + " bytes");
-				ActuallySendPacket(m_sendBuffer, numBytes, target);
+				ActuallySendPacket(m_sendBuffer, numBytes, target, out connectionReset);
 				return;
 			}
 
@@ -92,26 +94,39 @@ namespace Lidgren.Network
 
 			double now = NetTime.Now;
 
+			bool connectionReset;
+
 		RestartDelaySending:
 			foreach (DelayedPacket p in m_delayedPackets)
 			{
 				if (now > p.DelayedUntil)
 				{
-					ActuallySendPacket(p.Data, p.Data.Length, p.Target);
+					ActuallySendPacket(p.Data, p.Data.Length, p.Target, out connectionReset);
 					m_delayedPackets.Remove(p);
 					goto RestartDelaySending;
 				}
 			}
 		}
 
-		internal void ActuallySendPacket(byte[] data, int numBytes, IPEndPoint target)
+		internal void ActuallySendPacket(byte[] data, int numBytes, IPEndPoint target, out bool connectionReset)
 		{
+			connectionReset = false;
 			try
 			{
 				int bytesSent = m_socket.SendTo(data, 0, numBytes, SocketFlags.None, target);
 				if (numBytes != bytesSent)
 					LogWarning("Failed to send the full " + numBytes + "; only " + bytesSent + " bytes sent in packet!");
 			}
+			catch (SocketException sx)
+			{
+				if (sx.SocketErrorCode == SocketError.ConnectionReset)
+				{
+					// connection reset by peer, aka connection forcibly closed aka "ICMP port unreachable" 
+					connectionReset = true;
+					return;
+				}
+				LogError("Failed to send packet: " + sx);
+			}
 			catch (Exception ex)
 			{
 				LogError("Failed to send packet: " + ex);
@@ -122,7 +137,7 @@ namespace Lidgren.Network
 		//
 		// Release - just send the packet straight away
 		//
-		internal void SendPacket(int numBytes, IPEndPoint target, int numMessages)
+		internal void SendPacket(int numBytes, IPEndPoint target, int numMessages, out bool connectionReset)
 		{
 			try
 			{
@@ -130,6 +145,16 @@ namespace Lidgren.Network
 				if (numBytes != bytesSent)
 					LogWarning("Failed to send the full " + numBytes + "; only " + bytesSent + " bytes sent in packet!");
 			}
+			catch (SocketException sx)
+			{
+				if (sx.SocketErrorCode == SocketError.ConnectionReset)
+				{
+					// connection reset by peer, aka connection forcibly closed aka "ICMP port unreachable" 
+					connectionReset = true;
+					return;
+				}
+				LogError("Failed to send packet: " + sx);
+			}
 			catch (Exception ex)
 			{
 				LogError("Failed to send packet: " + ex);

Lidgren.Network/NetPeerConfiguration.cs

@@ -27,7 +27,7 @@ namespace Lidgren.Network
 	/// </summary>
 	public sealed class NetPeerConfiguration
 	{
-		private const string c_isLockedMessage = "You may not alter the NetPeerConfiguration after the NetPeer has been initialized!";
+		private const string c_isLockedMessage = "You may not modify the NetPeerConfiguration after it has been used to initialize a NetPeer";
 
 		private bool m_isLocked;
 		internal bool m_acceptIncomingConnections;

UnitTests/EncryptionTests.cs

@@ -58,16 +58,16 @@ namespace UnitTests
 
 			Console.WriteLine("Message encryption OK");
 
-			byte[] salt = NetUtility.ToByteArray("e6fb7e23f001f3e6c081"); // s
+			byte[] salt = NetUtility.ToByteArray("62191568b7a1aa18f8eb"); // s
 			byte[] verifier = NetSRP.ComputePasswordVerifier("user", "password", salt);
 
 			Console.WriteLine("v = " + NetUtility.ToHexString(verifier));
 
-			byte[] a = NetUtility.ToByteArray("3b6485358d1721cb438cb7d0b3c5f8f46186d43e1c47db7cd8aa80e19760e409");
+			byte[] a = NetUtility.ToByteArray("129aac7ce0be45ab5f65ec0c6879222386c32177cb4024fe7ad593341c0a5085");
 			byte[] A = NetSRP.ComputeClientChallenge(a);
 			Console.WriteLine("A = " + NetUtility.ToHexString(A));
 
-			byte[] b = NetUtility.ToByteArray("fc17d424ce73a4c73e8fedfb25839e9917e861bc5253fff65697f81c75a87ea3");
+			byte[] b = NetUtility.ToByteArray("cdbe8cec49e33c78c0b434be67fa2fdb7646776e757bcf59fad51bbbee0d53a1");
 			Console.WriteLine("b = " + NetUtility.ToHexString(b)); 
 			byte[] B = NetSRP.ComputeServerChallenge(b, verifier);
 			Console.WriteLine("B = " + NetUtility.ToHexString(B));