OpenSim.Region.ClientStack.LindenUDP.LLUDPServer.PacketReceived C# (CSharp) Method

        protected override void PacketReceived(UDPPacketBuffer buffer)
        {
            // Debugging/Profiling
            //try { Thread.CurrentThread.Name = "PacketReceived (" + m_scene.RegionInfo.RegionName + ")"; }
            //catch (Exception) { }

            LLUDPClient udpClient = null;
            Packet packet = null;
            int packetEnd = buffer.DataLength - 1;
            IPEndPoint address = (IPEndPoint)buffer.RemoteEndPoint;

            #region Decoding

            try
            {
                packet = Packet.BuildPacket(buffer.Data, ref packetEnd,
                    // Only allocate a buffer for zerodecoding if the packet is zerocoded
                    ((buffer.Data[0] & Helpers.MSG_ZEROCODED) != 0) ? new byte[4096] : null);
            }
            catch (MalformedDataException)
            {
            }

            // Fail-safe check
            if (packet == null)
            {
                m_log.ErrorFormat("[LLUDPSERVER]: Malformed data, cannot parse {0} byte packet from {1}:",
                    buffer.DataLength, buffer.RemoteEndPoint);
                m_log.Error(Utils.BytesToHexString(buffer.Data, buffer.DataLength, null));
                return;
            }

            #endregion Decoding

            #region Packet to Client Mapping

            // UseCircuitCode handling
            if (packet.Type == PacketType.UseCircuitCode)
            {
                object[] array = new object[] { buffer, packet };

                if (m_asyncPacketHandling)
                    Util.FireAndForget(HandleUseCircuitCode, array);
                else
                    HandleUseCircuitCode(array);

                return;
            }

            // Determine which agent this packet came from
            IClientAPI client;
            if (!m_scene.TryGetClient(address, out client) || !(client is LLClientView))
            {
                //m_log.Debug("[LLUDPSERVER]: Received a " + packet.Type + " packet from an unrecognized source: " + address + " in " + m_scene.RegionInfo.RegionName);
                return;
            }

            udpClient = ((LLClientView)client).UDPClient;

            if (!udpClient.IsConnected)
                return;

            #endregion Packet to Client Mapping

            // Stats tracking
            Interlocked.Increment(ref udpClient.PacketsReceived);

            int now = Environment.TickCount & Int32.MaxValue;
            udpClient.TickLastPacketReceived = now;

            #region ACK Receiving

            // Handle appended ACKs
            if (packet.Header.AppendedAcks && packet.Header.AckList != null)
            {
                for (int i = 0; i < packet.Header.AckList.Length; i++)
                    udpClient.NeedAcks.Remove(packet.Header.AckList[i], now, packet.Header.Resent);
            }

            // Handle PacketAck packets
            if (packet.Type == PacketType.PacketAck)
            {
                PacketAckPacket ackPacket = (PacketAckPacket)packet;

                for (int i = 0; i < ackPacket.Packets.Length; i++)
                    udpClient.NeedAcks.Remove(ackPacket.Packets[i].ID, now, packet.Header.Resent);

                // We don't need to do anything else with PacketAck packets
                return;
            }

            #endregion ACK Receiving

            #region ACK Sending

            if (packet.Header.Reliable)
            {
                udpClient.PendingAcks.Enqueue(packet.Header.Sequence);

                // This is a somewhat odd sequence of steps to pull the client.BytesSinceLastACK value out,
                // add the current received bytes to it, test if 2*MTU bytes have been sent, if so remove
                // 2*MTU bytes from the value and send ACKs, and finally add the local value back to
                // client.BytesSinceLastACK. Lockless thread safety
                int bytesSinceLastACK = Interlocked.Exchange(ref udpClient.BytesSinceLastACK, 0);
                bytesSinceLastACK += buffer.DataLength;
                if (bytesSinceLastACK > LLUDPServer.MTU * 2)
                {
                    bytesSinceLastACK -= LLUDPServer.MTU * 2;
                    SendAcks(udpClient);
                }
                Interlocked.Add(ref udpClient.BytesSinceLastACK, bytesSinceLastACK);
            }

            #endregion ACK Sending

            #region Incoming Packet Accounting

            // Check the archive of received reliable packet IDs to see whether we already received this packet
            if (packet.Header.Reliable && !udpClient.PacketArchive.TryEnqueue(packet.Header.Sequence))
            {
                if (packet.Header.Resent)
                    m_log.DebugFormat(
                        "[LLUDPSERVER]: Received a resend of already processed packet #{0}, type {1} from {2}", 
                        packet.Header.Sequence, packet.Type, client.Name);
                 else
                    m_log.WarnFormat(
                        "[LLUDPSERVER]: Received a duplicate (not marked as resend) of packet #{0}, type {1} from {2}",
                        packet.Header.Sequence, packet.Type, client.Name);

                // Avoid firing a callback twice for the same packet
                return;
            }

            #endregion Incoming Packet Accounting

            #region BinaryStats
            LogPacketHeader(true, udpClient.CircuitCode, 0, packet.Type, (ushort)packet.Length);
            #endregion BinaryStats

            #region Ping Check Handling

            if (packet.Type == PacketType.StartPingCheck)
            {
                // We don't need to do anything else with ping checks
                StartPingCheckPacket startPing = (StartPingCheckPacket)packet;
                CompletePing(udpClient, startPing.PingID.PingID);

                if ((Environment.TickCount - m_elapsedMSSinceLastStatReport) >= 3000)
                {
                    udpClient.SendPacketStats();
                    m_elapsedMSSinceLastStatReport = Environment.TickCount;
                }
                return;
            }
            else if (packet.Type == PacketType.CompletePingCheck)
            {
                // We don't currently track client ping times
                return;
            }

            #endregion Ping Check Handling

            // Inbox insertion
            packetInbox.Enqueue(new IncomingPacket(udpClient, packet));
        }

        public static ScenePresence AddChildClient(
            Scene scene, LLUDPServer udpServer, UUID agentId, UUID sessionId, uint circuitCode)
        {           
            IPEndPoint testEp = new IPEndPoint(IPAddress.Loopback, 999);

            UseCircuitCodePacket uccp = new UseCircuitCodePacket();

            UseCircuitCodePacket.CircuitCodeBlock uccpCcBlock
                = new UseCircuitCodePacket.CircuitCodeBlock();
            uccpCcBlock.Code = circuitCode;
            uccpCcBlock.ID = agentId;
            uccpCcBlock.SessionID = sessionId;
            uccp.CircuitCode = uccpCcBlock;

            byte[] uccpBytes = uccp.ToBytes();
            UDPPacketBuffer upb = new UDPPacketBuffer(testEp, uccpBytes.Length);
            upb.DataLength = uccpBytes.Length;  // God knows why this isn't set by the constructor.
            Buffer.BlockCopy(uccpBytes, 0, upb.Data, 0, uccpBytes.Length);

            AgentCircuitData acd = new AgentCircuitData();
            acd.AgentID = agentId;
            acd.SessionID = sessionId;

            scene.AuthenticateHandler.AddNewCircuit(circuitCode, acd);

            udpServer.PacketReceived(upb);

            return scene.GetScenePresence(agentId);
        }