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diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLPacketHandler.cs b/OpenSim/Region/ClientStack/LindenUDP/LLPacketHandler.cs
new file mode 100644
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--- /dev/null
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLPacketHandler.cs
@@ -0,0 +1,692 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSim Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Net;
+using System.Net.Sockets;
+using System.Timers;
+using libsecondlife;
+using libsecondlife.Packets;
+using Timer = System.Timers.Timer;
+using OpenSim.Framework;
+
+namespace OpenSim.Region.ClientStack.LindenUDP
+{
+    public delegate void PacketStats(int inPackets, int outPackets, int unAckedBytes);
+    public delegate void PacketDrop(Packet pack, Object id);
+    public delegate bool SynchronizeClientHandler(IScene scene, Packet packet, LLUUID agentID, ThrottleOutPacketType throttlePacketType);
+
+    public interface IPacketHandler
+    {
+        event PacketStats OnPacketStats;
+        event PacketDrop OnPacketDrop;
+        SynchronizeClientHandler SynchronizeClient { set; }
+
+        int PacketsReceived { get; }
+        int PacketsReceivedReported { get; }
+        uint SilenceLimit { get; set; }
+        uint DiscardTimeout { get; set; }
+        uint ResendTimeout { get; set; }
+
+        void InPacket(Packet packet);
+        void ProcessInPacket(Packet packet);
+        void OutPacket(Packet NewPack,
+                ThrottleOutPacketType throttlePacketType);
+        void OutPacket(Packet NewPack,
+                ThrottleOutPacketType throttlePacketType, Object id);
+        LLPacketQueue PacketQueue { get; }
+        void Stop();
+        void Flush();
+        void Clear();
+        ClientInfo GetClientInfo();
+        void SetClientInfo(ClientInfo info);
+        void AddImportantPacket(PacketType type);
+        void RemoveImportantPacket(PacketType type);
+    }
+
+    public class LLPacketHandler : IPacketHandler
+    {
+        // Packet queues
+        //
+        LLPacketQueue m_PacketQueue;
+
+        public LLPacketQueue PacketQueue
+        {
+            get { return m_PacketQueue; }
+        }
+
+        // Timer to run stats and acks on
+        //
+        private Timer m_AckTimer = new Timer(250);
+
+        // A list of the packets we haven't acked yet
+        //
+        private Dictionary<uint,uint> m_PendingAcks = new Dictionary<uint,uint>();
+        // Dictionary of the packets that need acks from the client.
+        //
+        private class AckData
+        {
+            public AckData(Packet packet, Object identifier)
+            {
+                Packet = packet;
+                Identifier = identifier;
+            }
+
+            public Packet Packet;
+            public Object Identifier;
+        }
+        private Dictionary<uint, AckData> m_NeedAck =
+                new Dictionary<uint, AckData>();
+
+        private uint m_ResendTimeout = 1000;
+
+        public uint ResendTimeout
+        {
+            get { return m_ResendTimeout; }
+            set { m_ResendTimeout = value; }
+        }
+
+        private uint m_DiscardTimeout = 8000;
+
+        public uint DiscardTimeout
+        {
+            get { return m_DiscardTimeout; }
+            set { m_DiscardTimeout = value; }
+        }
+
+        private uint m_SilenceLimit = 250;
+
+        public uint SilenceLimit
+        {
+            get { return m_SilenceLimit; }
+            set { m_SilenceLimit = value; }
+        }
+
+        private int m_LastAck = 0;
+
+        // Track duplicated packets. This uses a Dictionary. Both insertion
+        // and lookup are common operations and need to take advantage of
+        // the hashing. Expiration is less common and can be allowed the
+        // time for a linear scan.
+        //
+        private Dictionary<uint, int> m_DupeTracker =
+                new Dictionary<uint, int>();
+        private uint m_DupeTrackerWindow = 30;
+
+        // Values for the SimStatsReporter
+        //
+        private int m_PacketsReceived = 0;
+        private int m_PacketsReceivedReported = 0;
+        private int m_PacketsSent = 0;
+        private int m_PacketsSentReported = 0;
+        private int m_UnackedBytes = 0;
+
+        public int PacketsReceived
+        {
+            get { return m_PacketsReceived; }
+        }
+
+        public int PacketsReceivedReported
+        {
+            get { return m_PacketsReceivedReported; }
+        }
+
+        // The client we are working for
+        //
+        private IClientAPI m_Client;
+
+        // Some events
+        //
+        public event PacketStats OnPacketStats;
+        public event PacketDrop OnPacketDrop;
+
+        private SynchronizeClientHandler m_SynchronizeClient = null;
+
+        public SynchronizeClientHandler SynchronizeClient
+        {
+            set { m_SynchronizeClient = value; }
+        }
+
+        // Packet sequencing
+        //
+        private uint m_Sequence = 0;
+        private object m_SequenceLock = new object();
+        private const int MAX_SEQUENCE = 0xFFFFFF;
+
+        List<PacketType> m_ImportantPackets = new List<PacketType>();
+
+        ////////////////////////////////////////////////////////////////////
+
+        // Constructors
+        //
+        public LLPacketHandler(IClientAPI client)
+        {
+            m_Client = client;
+
+            m_PacketQueue = new LLPacketQueue(client.AgentId);
+
+            m_AckTimer.Elapsed += AckTimerElapsed;
+            m_AckTimer.Start();
+        }
+
+        public void Stop()
+        {
+            m_AckTimer.Stop();
+
+            m_PacketQueue.Enqueue(null);
+        }
+
+        // Send one packet. This actually doesn't send anything, it queues
+        // it. Designed to be fire-and-forget, but there is an optional
+        // notifier.
+        //
+        public void OutPacket(
+                Packet packet, ThrottleOutPacketType throttlePacketType)
+        {
+            OutPacket(packet, throttlePacketType, null);
+        }
+
+        public void OutPacket(
+                Packet packet, ThrottleOutPacketType throttlePacketType,
+                Object id)
+        {
+            // Call the load balancer's hook. If this is not active here
+            // we defer to the sim server this client is actually connected
+            // to. Packet drop notifies will not be triggered in this 
+            // configuration!
+            //
+            if ((m_SynchronizeClient != null) && (!m_Client.IsActive))
+            {
+                if (m_SynchronizeClient(m_Client.Scene, packet,
+                        m_Client.AgentId, throttlePacketType))
+                    return;
+            }
+
+            packet.Header.Sequence = NextPacketSequenceNumber();
+
+            lock(m_NeedAck)
+            {
+                DropResend(id);
+
+                QueuePacket(packet, throttlePacketType, id);
+
+                // We want to see that packet arrive if it's reliable
+                if(packet.Header.Reliable)
+                {
+                    m_UnackedBytes += packet.ToBytes().Length;
+                    m_NeedAck[packet.Header.Sequence] = new AckData(packet, id);
+                }
+            }
+        }
+
+        private void QueuePacket(
+                Packet packet, ThrottleOutPacketType throttlePacketType,
+                Object id)
+        {
+            // Add acks to outgoing packets
+            //
+            lock(m_PendingAcks)
+            {
+                if(m_PendingAcks.Count > 0)
+                {
+                    int count = m_PendingAcks.Count;
+                    if(count > 10)
+                        count = 10;
+                    packet.Header.AckList = new uint[count];
+
+                    int i = 0;
+
+                    foreach (uint ack in new List<uint>(m_PendingAcks.Keys))
+                    {
+                        packet.Header.AckList[i] = ack;
+                        i++;
+                        m_PendingAcks.Remove(ack);
+                        if (i >= 10) // That is how much space there is
+                            break;
+                    }
+                }
+            }
+
+            packet.TickCount = System.Environment.TickCount;
+
+            LLQueItem item = new LLQueItem();
+            item.Packet = packet;
+            item.Incoming = false;
+            item.throttleType = throttlePacketType;
+            item.Identifier = id;
+
+            m_PacketQueue.Enqueue(item);
+            m_PacketsSent++;
+        }
+
+        private void ResendUnacked()
+        {
+            int now = System.Environment.TickCount;
+            int lastAck = m_LastAck;
+            
+            // Unless we have received at least one ack, don't bother resending
+            // anything. There may not be a client there, don't clog up the
+            // pipes.
+            //
+            if(lastAck == 0)
+                return;
+
+            lock (m_NeedAck)
+            {
+                // Nothing to do
+                //
+                if(m_NeedAck.Count == 0)
+                    return;
+
+                // If we have seen no acks in <SilenceLimit> s but are
+                // waiting for acks, then there may be no one listening.
+                // No need to resend anything. Keep it until it gets stale,
+                // then it will be dropped.
+                //
+                if (((now - lastAck) > m_SilenceLimit) &&
+                        m_NeedAck.Count > 0)
+                {
+                    return;
+                }
+
+                foreach (AckData data in new List<AckData>(m_NeedAck.Values))
+                {
+                    Packet packet = data.Packet;
+
+                    // Packets this old get resent
+                    //
+                    if ((now - packet.TickCount) > m_ResendTimeout)
+                    {
+                        // Resend the packet. Set the packet's tick count to
+                        // now, and keep it marked as resent.
+                        //
+                        packet.Header.Resent = true;
+                        QueuePacket(packet, ThrottleOutPacketType.Resend,
+                                data.Identifier);
+                    }
+
+                    // The discard logic
+                    // If the packet is in the queue for <DiscardTimeout> s
+                    // without having been processed, then we have clogged
+                    // pipes. Most likely, the client is gone
+                    // Drop the packets
+                    //
+                    if ((now - packet.TickCount) > m_DiscardTimeout)
+                    {
+                        if(!m_ImportantPackets.Contains(packet.Type))
+                            m_NeedAck.Remove(packet.Header.Sequence);
+
+                        TriggerOnPacketDrop(packet, data.Identifier);
+
+                        continue;
+                    }
+                }
+            }
+        }
+
+        // Send the pending packet acks to the client
+        // Will send blocks of acks for up to 250 packets
+        //
+        private void SendAcks()
+        {
+            lock (m_PendingAcks)
+            {
+                if (m_PendingAcks.Count == 0)
+                    return;
+
+                PacketAckPacket acks = (PacketAckPacket)PacketPool.Instance.GetPacket(PacketType.PacketAck);
+
+                // The case of equality is more common than one might think,
+                // because this function will be called unconditionally when
+                // the counter reaches 250. So there is a good chance another
+                // packet with 250 blocks exists.
+                //
+                if(acks.Packets == null ||
+                        acks.Packets.Length != m_PendingAcks.Count)
+                    acks.Packets = new PacketAckPacket.PacketsBlock[m_PendingAcks.Count];
+                int i = 0;
+                foreach (uint ack in new List<uint>(m_PendingAcks.Keys))
+                {
+                    acks.Packets[i] = new PacketAckPacket.PacketsBlock();
+                    acks.Packets[i].ID = ack;
+
+                    m_PendingAcks.Remove(ack);
+                    i++;
+                }
+
+                acks.Header.Reliable = false;
+                OutPacket(acks, ThrottleOutPacketType.Unknown);
+            }
+        }
+
+        // Queue a packet ack. It will be sent either after 250 acks are
+        // queued, or when the timer fires.
+        //
+        private void AckPacket(Packet packet)
+        {
+            lock (m_PendingAcks)
+            {
+                if(m_PendingAcks.Count < 250)
+                {
+                                        if(!m_PendingAcks.ContainsKey(packet.Header.Sequence))
+                                                m_PendingAcks.Add(packet.Header.Sequence,
+                                                                packet.Header.Sequence);
+                    return;
+                }
+            }
+
+            SendAcks();
+
+            lock (m_PendingAcks)
+            {
+                // If this is still full we have a truly exceptional
+                // condition (means, can't happen)
+                //
+                if(m_PendingAcks.Count < 250)
+                {
+                                        if(!m_PendingAcks.ContainsKey(packet.Header.Sequence))
+                                                m_PendingAcks.Add(packet.Header.Sequence,
+                                                                packet.Header.Sequence);
+                    return;
+                }
+            }
+        }
+
+        // When the timer elapses, send the pending acks, trigger resends
+        // and report all the stats.
+        //
+        private void AckTimerElapsed(object sender, ElapsedEventArgs ea)
+        {
+            SendAcks();
+            ResendUnacked();
+            SendPacketStats();
+        }
+
+        // Push out pachet counts for the sim status reporter
+        //
+        private void SendPacketStats()
+        {
+            PacketStats handlerPacketStats = OnPacketStats;
+            if (handlerPacketStats != null)
+            {
+                handlerPacketStats(
+                        m_PacketsReceived - m_PacketsReceivedReported,
+                        m_PacketsSent - m_PacketsSentReported,
+                        m_UnackedBytes);
+
+                m_PacketsReceivedReported = m_PacketsReceived;
+                m_PacketsSentReported = m_PacketsSent;
+            }
+        }
+
+        // We can't keep an unlimited record of dupes. This will prune the
+        // dictionary by age.
+        //
+        private void PruneDupeTracker()
+        {
+            lock (m_DupeTracker)
+            {
+                Dictionary<uint, int> packs =
+                        new Dictionary<uint, int>(m_DupeTracker);
+
+                foreach (uint pack in packs.Keys)
+                {
+                    if(Util.UnixTimeSinceEpoch() - m_DupeTracker[pack] >
+                            m_DupeTrackerWindow)
+                        m_DupeTracker.Remove(pack);
+                }
+            }
+        }
+
+        public void InPacket(Packet packet)
+        {
+            if(packet == null)
+                return;
+
+            // If this client is on another partial instance, no need
+            // to handle packets
+            //
+            if(!m_Client.IsActive && packet.Type != PacketType.LogoutRequest)
+            {
+                PacketPool.Instance.ReturnPacket(packet);
+                return;
+            }
+
+            // Any packet can have some packet acks in the header.
+            // Process them here
+            //
+            if(packet.Header.AppendedAcks)
+            {
+                foreach(uint id in packet.Header.AckList)
+                {
+                    ProcessAck(id);
+                }
+            }
+
+            // When too many acks are needed to be sent, the client sends
+            // a packet consisting of acks only
+            //
+            if(packet.Type == PacketType.PacketAck)
+            {
+                PacketAckPacket ackPacket = (PacketAckPacket)packet;
+
+                foreach (PacketAckPacket.PacketsBlock block in
+                        ackPacket.Packets)
+                {
+                    ProcessAck(block.ID);
+                }
+
+                PacketPool.Instance.ReturnPacket(packet);
+                return;
+            }
+            else if(packet.Type == PacketType.StartPingCheck)
+            {
+                StartPingCheckPacket startPing = (StartPingCheckPacket)packet;
+                CompletePingCheckPacket endPing = (CompletePingCheckPacket)PacketPool.Instance.GetPacket(PacketType.CompletePingCheck);
+
+                endPing.PingID.PingID = startPing.PingID.PingID;
+                OutPacket(endPing, ThrottleOutPacketType.Task);
+            }
+            else
+            {
+                LLQueItem item = new LLQueItem();
+                item.Packet = packet;
+                item.Incoming = true;
+                m_PacketQueue.Enqueue(item);
+            }
+        }
+
+        public void ProcessInPacket(Packet packet)
+        {
+            // Always ack the packet!
+            //
+            AckPacket(packet);
+
+            if (packet.Type != PacketType.AgentUpdate)
+                m_PacketsReceived++;
+
+            // Check for duplicate packets..    packets that the client is 
+            // resending because it didn't receive our ack
+            //
+            lock (m_DupeTracker)
+            {
+                if (m_DupeTracker.ContainsKey(packet.Header.Sequence))
+                    return;
+
+                m_DupeTracker.Add(packet.Header.Sequence,
+                        Util.UnixTimeSinceEpoch());
+            }
+
+            m_Client.ProcessInPacket(packet);
+        }
+
+        public void Flush()
+        {
+            m_PacketQueue.Flush();
+        }
+
+        public void Clear()
+        {
+            m_NeedAck.Clear();
+            m_PendingAcks.Clear();
+            m_Sequence += 1000000;
+        }
+
+        private void ProcessAck(uint id)
+        {
+            AckData data;
+            Packet packet;
+
+            lock(m_NeedAck)
+            {
+                if(!m_NeedAck.TryGetValue(id, out data))
+                    return;
+
+                packet = data.Packet;
+
+                m_NeedAck.Remove(id);
+                m_UnackedBytes -= packet.ToBytes().Length;
+
+                m_LastAck = System.Environment.TickCount;
+            }
+        }
+
+        // Allocate packet sequence numbers in a threadsave manner
+        //
+        protected uint NextPacketSequenceNumber()
+        {
+            // Set the sequence number
+            uint seq = 1;
+            lock (m_SequenceLock)
+            {
+                if (m_Sequence >= MAX_SEQUENCE)
+                {
+                    m_Sequence = 1;
+                }
+                else
+                {
+                    m_Sequence++;
+                }
+                seq = m_Sequence;
+            }
+            return seq;
+        }
+
+        public ClientInfo GetClientInfo()
+        {
+            ClientInfo info = new ClientInfo();
+            info.pendingAcks = m_PendingAcks;
+            info.needAck = new Dictionary<uint, byte[]>();
+
+            lock (m_NeedAck)
+            {
+                foreach (uint key in m_NeedAck.Keys)
+                    info.needAck.Add(key, m_NeedAck[key].Packet.ToBytes());
+            }
+
+            LLQueItem[] queitems = m_PacketQueue.GetQueueArray();
+
+            for (int i = 0; i < queitems.Length; i++)
+            {
+                if (queitems[i].Incoming == false)
+                    info.out_packets.Add(queitems[i].Packet.ToBytes());
+            }
+
+            info.sequence = m_Sequence;
+
+            return info;
+        }
+
+        public void SetClientInfo(ClientInfo info)
+        {
+            m_PendingAcks = info.pendingAcks;
+            m_NeedAck = new Dictionary<uint, AckData>();
+
+            Packet packet = null;
+            int packetEnd = 0;
+            byte[] zero = new byte[3000];
+
+            foreach (uint key in info.needAck.Keys)
+            {
+                byte[] buff = info.needAck[key];
+                packetEnd = buff.Length - 1;
+
+                try
+                {
+                    packet = PacketPool.Instance.GetPacket(buff, ref packetEnd, zero);
+                }
+                catch (Exception)
+                {
+                }
+
+                m_NeedAck.Add(key, new AckData(packet, null));
+            }
+
+            m_Sequence = info.sequence;
+        }
+        
+        public void AddImportantPacket(PacketType type)
+        {
+            if(m_ImportantPackets.Contains(type))
+                return;
+
+            m_ImportantPackets.Add(type);
+        }
+
+        public void RemoveImportantPacket(PacketType type)
+        {
+            if(!m_ImportantPackets.Contains(type))
+                return;
+
+            m_ImportantPackets.Remove(type);
+        }
+        
+        private void DropResend(Object id)
+        {
+            foreach (AckData data in new List<AckData>(m_NeedAck.Values))
+            {
+                if(data.Identifier != null && data.Identifier == id)
+                {
+                    m_NeedAck.Remove(data.Packet.Header.Sequence);
+                    return;
+                }
+            }
+        }
+
+        private void TriggerOnPacketDrop(Packet packet, Object id)
+        {
+            PacketDrop handlerPacketDrop = OnPacketDrop;
+
+            if(handlerPacketDrop == null)
+                return;
+
+            handlerPacketDrop(packet, id);
+        }
+    }
+}