* Copied LocklessQueue.cs into OpenSim.Framework and added the .Count property and .Clear() method

* Changed the way the QueueEmpty callback is fired. It will be fired asynchronously as soon as an empty queue is detected (this can happen immediately following a dequeue), and will not be fired again until at least one packet is dequeued from that queue. This will give callbacks advanced notice of an empty queue and prevent callbacks from stacking up while the queue is empty
* Added LLUDPClient.IsConnected checks in several places to prevent unwanted network activity after a client disconnects
* Prevent LLClientView.Close() from being called twice every disconnect
* Removed the packet resend limit and improved the client timeout check

1 files changed, 48 insertions, 59 deletions

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
index 8689af3..57fee59 100644
--- a/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs
@@ -332,8 +332,19 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
         public void ResendUnacked(LLUDPClient udpClient)
         {
-            if (udpClient.NeedAcks.Count > 0)
+            if (udpClient.IsConnected && udpClient.NeedAcks.Count > 0)
             {
+                // Disconnect an agent if no packets are received for some time
+                //FIXME: Make 60 an .ini setting
+                if (Environment.TickCount - udpClient.TickLastPacketReceived > 1000 * 60)
+                {
+                    m_log.Warn("[LLUDPSERVER]: Ack timeout, disconnecting " + udpClient.AgentID);
+
+                    RemoveClient(udpClient);
+                    return;
+                }
+
+                // Get a list of all of the packets that have been sitting unacked longer than udpClient.RTO
                 List<OutgoingPacket> expiredPackets = udpClient.NeedAcks.GetExpiredPackets(udpClient.RTO);
 
                 if (expiredPackets != null)
@@ -343,48 +354,24 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                     {
                         OutgoingPacket outgoingPacket = expiredPackets[i];
 
-                        // FIXME: Make this an .ini setting
-                        if (outgoingPacket.ResendCount < 3)
-                        {
-                            //Logger.Debug(String.Format("Resending packet #{0} (attempt {1}), {2}ms have passed",
-                            //    outgoingPacket.SequenceNumber, outgoingPacket.ResendCount, Environment.TickCount - outgoingPacket.TickCount));
+                        //m_log.DebugFormat("[LLUDPSERVER]: Resending packet #{0} (attempt {1}), {2}ms have passed",
+                        //    outgoingPacket.SequenceNumber, outgoingPacket.ResendCount, Environment.TickCount - outgoingPacket.TickCount);
 
-                            // Set the resent flag
-                            outgoingPacket.Buffer.Data[0] = (byte)(outgoingPacket.Buffer.Data[0] | Helpers.MSG_RESENT);
-                            outgoingPacket.Category = ThrottleOutPacketType.Resend;
+                        // Set the resent flag
+                        outgoingPacket.Buffer.Data[0] = (byte)(outgoingPacket.Buffer.Data[0] | Helpers.MSG_RESENT);
+                        outgoingPacket.Category = ThrottleOutPacketType.Resend;
 
-                            // The TickCount will be set to the current time when the packet
-                            // is actually sent out again
-                            outgoingPacket.TickCount = 0;
+                        // The TickCount will be set to the current time when the packet
+                        // is actually sent out again
+                        outgoingPacket.TickCount = 0;
 
-                            // Bump up the resend count on this packet
-                            Interlocked.Increment(ref outgoingPacket.ResendCount);
-                            //Interlocked.Increment(ref Stats.ResentPackets);
+                        // Bump up the resend count on this packet
+                        Interlocked.Increment(ref outgoingPacket.ResendCount);
+                        //Interlocked.Increment(ref Stats.ResentPackets);
 
-                            // Queue or (re)send the packet
-                            if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket))
-                                SendPacketFinal(outgoingPacket);
-                        }
-                        else
-                        {
-                            m_log.DebugFormat("[LLUDPSERVER]: Dropping packet #{0} for agent {1} after {2} failed attempts",
-                                outgoingPacket.SequenceNumber, outgoingPacket.Client.RemoteEndPoint, outgoingPacket.ResendCount);
-
-                            lock (udpClient.NeedAcks.SyncRoot)
-                                udpClient.NeedAcks.RemoveUnsafe(outgoingPacket.SequenceNumber);
-
-                            //Interlocked.Increment(ref Stats.DroppedPackets);
-
-                            // Disconnect an agent if no packets are received for some time
-                            //FIXME: Make 60 an .ini setting
-                            if (Environment.TickCount - udpClient.TickLastPacketReceived > 1000 * 60)
-                            {
-                                m_log.Warn("[LLUDPSERVER]: Ack timeout, disconnecting " + udpClient.AgentID);
-
-                                RemoveClient(udpClient);
-                                return;
-                            }
-                        }
+                        // Requeue or resend the packet
+                        if (!outgoingPacket.Client.EnqueueOutgoing(outgoingPacket))
+                            SendPacketFinal(outgoingPacket);
                     }
                 }
             }
@@ -403,6 +390,9 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             bool isReliable = (flags & Helpers.MSG_RELIABLE) != 0;
             LLUDPClient udpClient = outgoingPacket.Client;
 
+            if (!udpClient.IsConnected)
+                return;
+
             // Keep track of when this packet was sent out (right now)
             outgoingPacket.TickCount = Environment.TickCount;
 
@@ -481,14 +471,15 @@ namespace OpenSim.Region.ClientStack.LindenUDP
             }
             catch (MalformedDataException)
             {
-                m_log.ErrorFormat("[LLUDPSERVER]: Malformed data, cannot parse packet:\n{0}",
-                    Utils.BytesToHexString(buffer.Data, buffer.DataLength, null));
+                m_log.ErrorFormat("[LLUDPSERVER]: Malformed data, cannot parse packet from {0}:\n{1}",
+                    buffer.RemoteEndPoint, Utils.BytesToHexString(buffer.Data, buffer.DataLength, null));
             }
 
             // Fail-safe check
             if (packet == null)
             {
-                m_log.Warn("[LLUDPSERVER]: Couldn't build a message from the incoming data");
+                m_log.Warn("[LLUDPSERVER]: Couldn't build a message from incoming data " + buffer.DataLength +
+                    " bytes long from " + buffer.RemoteEndPoint);
                 return;
             }
 
@@ -513,6 +504,9 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
             udpClient = ((LLClientView)client).UDPClient;
 
+            if (!udpClient.IsConnected)
+                return;
+
             #endregion Packet to Client Mapping
 
             // Stats tracking
@@ -643,7 +637,6 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                 // Create the LLClientView
                 LLClientView client = new LLClientView(remoteEndPoint, m_scene, this, udpClient, sessionInfo, agentID, sessionID, circuitCode);
                 client.OnLogout += LogoutHandler;
-                client.OnConnectionClosed += ConnectionClosedHandler;
 
                 // Start the IClientAPI
                 client.Start();
@@ -745,17 +738,20 @@ namespace OpenSim.Region.ClientStack.LindenUDP
                         {
                             LLUDPClient udpClient = ((LLClientView)client).UDPClient;
 
-                            if (udpClient.DequeueOutgoing())
-                                packetSent = true;
-                            if (resendUnacked)
-                                ResendUnacked(udpClient);
-                            if (sendAcks)
+                            if (udpClient.IsConnected)
                             {
-                                SendAcks(udpClient);
-                                udpClient.SendPacketStats();
+                                if (udpClient.DequeueOutgoing())
+                                    packetSent = true;
+                                if (resendUnacked)
+                                    ResendUnacked(udpClient);
+                                if (sendAcks)
+                                {
+                                    SendAcks(udpClient);
+                                    udpClient.SendPacketStats();
+                                }
+                                if (sendPings)
+                                    SendPing(udpClient);
                             }
-                            if (sendPings)
-                                SendPing(udpClient);
                         }
                     }
                 );
@@ -808,14 +804,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
         private void LogoutHandler(IClientAPI client)
         {
-            client.OnLogout -= LogoutHandler;
             client.SendLogoutPacket();
         }
-
-        private void ConnectionClosedHandler(IClientAPI client)
-        {
-            client.OnConnectionClosed -= ConnectionClosedHandler;
-            RemoveClient(((LLClientView)client).UDPClient);
-        }
     }
 }