1 files changed, 370 insertions, 0 deletions

diff --git a/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs b/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
new file mode 100644
index 0000000..ad01135
--- /dev/null
+++ b/OpenSim/Region/ClientStack/LindenUDP/LLUDPClient.cs
@@ -0,0 +1,370 @@
+/*
+ * 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 OpenSimulator 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.Generic;
+using System.Net;
+using OpenSim.Framework;
+using OpenMetaverse;
+
+namespace OpenSim.Region.ClientStack.LindenUDP
+{
+    public delegate void QueueEmpty(ThrottleOutPacketType category);
+
+    public class LLUDPClient
+    {
+        /// <summary>The number of packet categories to throttle on. If a throttle category is added
+        /// or removed, this number must also change</summary>
+        const int THROTTLE_CATEGORY_COUNT = 7;
+
+        public event QueueEmpty OnQueueEmpty;
+
+        /// <summary>AgentID for this client</summary>
+        public readonly UUID AgentID;
+        /// <summary>The remote address of the connected client</summary>
+        public readonly IPEndPoint RemoteEndPoint;
+        /// <summary>Circuit code that this client is connected on</summary>
+        public readonly uint CircuitCode;
+        /// <summary>Sequence numbers of packets we've received (for duplicate checking)</summary>
+        public readonly IncomingPacketHistoryCollection PacketArchive = new IncomingPacketHistoryCollection(200);
+        /// <summary>Packets we have sent that need to be ACKed by the client</summary>
+        public readonly UnackedPacketCollection NeedAcks = new UnackedPacketCollection();
+        /// <summary>ACKs that are queued up, waiting to be sent to the client</summary>
+        public readonly LocklessQueue<uint> PendingAcks = new LocklessQueue<uint>();
+
+        /// <summary>Reference to the IClientAPI for this client</summary>
+        public LLClientView ClientAPI;
+        /// <summary>Current packet sequence number</summary>
+        public int CurrentSequence;
+        /// <summary>Current ping sequence number</summary>
+        public byte CurrentPingSequence;
+        /// <summary>True when this connection is alive, otherwise false</summary>
+        public bool IsConnected = true;
+        /// <summary>True when this connection is paused, otherwise false</summary>
+        public bool IsPaused = true;
+        /// <summary>Environment.TickCount when the last packet was received for this client</summary>
+        public int TickLastPacketReceived;
+
+        /// <summary>Timer granularity. This is set to the measured resolution of Environment.TickCount</summary>
+        public readonly float G;
+        /// <summary>Smoothed round-trip time. A smoothed average of the round-trip time for sending a
+        /// reliable packet to the client and receiving an ACK</summary>
+        public float SRTT;
+        /// <summary>Round-trip time variance. Measures the consistency of round-trip times</summary>
+        public float RTTVAR;
+        /// <summary>Retransmission timeout. Packets that have not been acknowledged in this number of
+        /// milliseconds or longer will be resent</summary>
+        /// <remarks>Calculated from <seealso cref="SRTT"/> and <seealso cref="RTTVAR"/> using the
+        /// guidelines in RFC 2988</remarks>
+        public int RTO;
+        /// <summary>Number of bytes received since the last acknowledgement was sent out. This is used
+        /// to loosely follow the TCP delayed ACK algorithm in RFC 1122 (4.2.3.2)</summary>
+        public int BytesSinceLastACK;
+
+        /// <summary>Throttle bucket for this agent's connection</summary>
+        private readonly TokenBucket throttle;
+        /// <summary>Throttle buckets for each packet category</summary>
+        private readonly TokenBucket[] throttleCategories;
+        /// <summary>Throttle rate defaults and limits</summary>
+        private readonly ThrottleRates defaultThrottleRates;
+        /// <summary>Outgoing queues for throttled packets</summary>
+        private readonly LocklessQueue<OutgoingPacket>[] packetOutboxes = new LocklessQueue<OutgoingPacket>[THROTTLE_CATEGORY_COUNT];
+        /// <summary>A container that can hold one packet for each outbox, used to store
+        /// dequeued packets that are being held for throttling</summary>
+        private readonly OutgoingPacket[] nextPackets = new OutgoingPacket[THROTTLE_CATEGORY_COUNT];
+        /// <summary>An optimization to store the length of dequeued packets being held
+        /// for throttling. This avoids expensive calls to Packet.Length</summary>
+        private readonly int[] nextPacketLengths = new int[THROTTLE_CATEGORY_COUNT];
+        /// <summary>A reference to the LLUDPServer that is managing this client</summary>
+        private readonly LLUDPServer udpServer;
+
+        public LLUDPClient(LLUDPServer server, ThrottleRates rates, TokenBucket parentThrottle, uint circuitCode, UUID agentID, IPEndPoint remoteEndPoint)
+        {
+            udpServer = server;
+            AgentID = agentID;
+            RemoteEndPoint = remoteEndPoint;
+            CircuitCode = circuitCode;
+            defaultThrottleRates = rates;
+
+            for (int i = 0; i < THROTTLE_CATEGORY_COUNT; i++)
+                packetOutboxes[i] = new LocklessQueue<OutgoingPacket>();
+
+            throttle = new TokenBucket(parentThrottle, 0, 0);
+            throttleCategories = new TokenBucket[THROTTLE_CATEGORY_COUNT];
+            throttleCategories[(int)ThrottleOutPacketType.Resend] = new TokenBucket(throttle, rates.ResendLimit, rates.Resend);
+            throttleCategories[(int)ThrottleOutPacketType.Land] = new TokenBucket(throttle, rates.LandLimit, rates.Land);
+            throttleCategories[(int)ThrottleOutPacketType.Wind] = new TokenBucket(throttle, rates.WindLimit, rates.Wind);
+            throttleCategories[(int)ThrottleOutPacketType.Cloud] = new TokenBucket(throttle, rates.CloudLimit, rates.Cloud);
+            throttleCategories[(int)ThrottleOutPacketType.Task] = new TokenBucket(throttle, rates.TaskLimit, rates.Task);
+            throttleCategories[(int)ThrottleOutPacketType.Texture] = new TokenBucket(throttle, rates.TextureLimit, rates.Texture);
+            throttleCategories[(int)ThrottleOutPacketType.Asset] = new TokenBucket(throttle, rates.AssetLimit, rates.Asset);
+
+            // Set the granularity variable used for retransmission calculations to
+            // the measured resolution of Environment.TickCount
+            G = server.TickCountResolution;
+
+            // Default the retransmission timeout to three seconds
+            RTO = 3000;
+        }
+
+        public void Shutdown()
+        {
+            IsConnected = false;
+        }
+
+        public ClientInfo GetClientInfo()
+        {
+            // TODO: This data structure is wrong in so many ways
+            ClientInfo info = new ClientInfo();
+            info.pendingAcks = new Dictionary<uint, uint>();
+            info.needAck = new Dictionary<uint, byte[]>();
+
+            info.resendThrottle = throttleCategories[(int)ThrottleOutPacketType.Resend].DripRate;
+            info.landThrottle = throttleCategories[(int)ThrottleOutPacketType.Land].DripRate;
+            info.windThrottle = throttleCategories[(int)ThrottleOutPacketType.Wind].DripRate;
+            info.cloudThrottle = throttleCategories[(int)ThrottleOutPacketType.Cloud].DripRate;
+            info.taskThrottle = throttleCategories[(int)ThrottleOutPacketType.Task].DripRate;
+            info.assetThrottle = throttleCategories[(int)ThrottleOutPacketType.Asset].DripRate;
+            info.textureThrottle = throttleCategories[(int)ThrottleOutPacketType.Texture].DripRate;
+            info.totalThrottle = info.resendThrottle + info.landThrottle + info.windThrottle + info.cloudThrottle +
+                info.taskThrottle + info.assetThrottle + info.textureThrottle;
+
+            return info;
+        }
+
+        public void SetClientInfo(ClientInfo info)
+        {
+        }
+
+        public string GetStats()
+        {
+            return string.Format("{0,7} {1,7} {2,7} {3,7} {4,7} {5,7} {6,7} {7,7} {8,7} {9,7}",
+                0,
+                0,
+                0,
+                0,
+                0,
+                0,
+                0,
+                0,
+                0,
+                0);
+        }
+
+        public void SetThrottles(byte[] throttleData)
+        {
+            byte[] adjData;
+            int pos = 0;
+
+            if (!BitConverter.IsLittleEndian)
+            {
+                byte[] newData = new byte[7 * 4];
+                Buffer.BlockCopy(throttleData, 0, newData, 0, 7 * 4);
+
+                for (int i = 0; i < 7; i++)
+                    Array.Reverse(newData, i * 4, 4);
+
+                adjData = newData;
+            }
+            else
+            {
+                adjData = throttleData;
+            }
+
+            int resend = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f); pos += 4;
+            int land = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f); pos += 4;
+            int wind = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f); pos += 4;
+            int cloud = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f); pos += 4;
+            int task = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f); pos += 4;
+            int texture = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f); pos += 4;
+            int asset = (int)(BitConverter.ToSingle(adjData, pos) * 0.125f);
+
+            resend = (resend <= defaultThrottleRates.ResendLimit) ? resend : defaultThrottleRates.ResendLimit;
+            land = (land <= defaultThrottleRates.LandLimit) ? land : defaultThrottleRates.LandLimit;
+            wind = (wind <= defaultThrottleRates.WindLimit) ? wind : defaultThrottleRates.WindLimit;
+            cloud = (cloud <= defaultThrottleRates.CloudLimit) ? cloud : defaultThrottleRates.CloudLimit;
+            task = (task <= defaultThrottleRates.TaskLimit) ? task : defaultThrottleRates.TaskLimit;
+            texture = (texture <= defaultThrottleRates.TextureLimit) ? texture : defaultThrottleRates.TextureLimit;
+            asset = (asset <= defaultThrottleRates.AssetLimit) ? asset : defaultThrottleRates.AssetLimit;
+
+            SetThrottle(ThrottleOutPacketType.Resend, resend);
+            SetThrottle(ThrottleOutPacketType.Land, land);
+            SetThrottle(ThrottleOutPacketType.Wind, wind);
+            SetThrottle(ThrottleOutPacketType.Cloud, cloud);
+            SetThrottle(ThrottleOutPacketType.Task, task);
+            SetThrottle(ThrottleOutPacketType.Texture, texture);
+            SetThrottle(ThrottleOutPacketType.Asset, asset);
+        }
+
+        public byte[] GetThrottlesPacked()
+        {
+            byte[] data = new byte[7 * 4];
+            int i = 0;
+
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Resend].DripRate), 0, data, i, 4); i += 4;
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Land].DripRate), 0, data, i, 4); i += 4;
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Wind].DripRate), 0, data, i, 4); i += 4;
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Cloud].DripRate), 0, data, i, 4); i += 4;
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Task].DripRate), 0, data, i, 4); i += 4;
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Texture].DripRate), 0, data, i, 4); i += 4;
+            Buffer.BlockCopy(Utils.FloatToBytes((float)throttleCategories[(int)ThrottleOutPacketType.Asset].DripRate), 0, data, i, 4); i += 4;
+
+            return data;
+        }
+
+        public void SetThrottle(ThrottleOutPacketType category, int rate)
+        {
+            int i = (int)category;
+            if (i >= 0 && i < throttleCategories.Length)
+            {
+                TokenBucket bucket = throttleCategories[(int)category];
+                bucket.MaxBurst = rate;
+                bucket.DripRate = rate;
+            }
+        }
+
+        public bool EnqueueOutgoing(OutgoingPacket packet)
+        {
+            int category = (int)packet.Category;
+
+            if (category >= 0 && category < packetOutboxes.Length)
+            {
+                LocklessQueue<OutgoingPacket> queue = packetOutboxes[category];
+                TokenBucket bucket = throttleCategories[category];
+
+                if (throttleCategories[category].RemoveTokens(packet.Buffer.DataLength))
+                {
+                    // Enough tokens were removed from the bucket, the packet will not be queued
+                    return false;
+                }
+                else
+                {
+                    // Not enough tokens in the bucket, queue this packet
+                    queue.Enqueue(packet);
+                    return true;
+                }
+            }
+            else
+            {
+                // We don't have a token bucket for this category, so it will not be queued
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Loops through all of the packet queues for this client and tries to send
+        /// any outgoing packets, obeying the throttling bucket limits
+        /// </summary>
+        /// <remarks>This function is only called from a synchronous loop in the
+        /// UDPServer so we don't need to bother making this thread safe</remarks>
+        /// <returns>True if any packets were sent, otherwise false</returns>
+        public bool DequeueOutgoing()
+        {
+            OutgoingPacket packet;
+            LocklessQueue<OutgoingPacket> queue;
+            TokenBucket bucket;
+            bool packetSent = false;
+
+            for (int i = 0; i < THROTTLE_CATEGORY_COUNT; i++)
+            {
+                bucket = throttleCategories[i];
+
+                if (nextPackets[i] != null)
+                {
+                    // This bucket was empty the last time we tried to send a packet,
+                    // leaving a dequeued packet still waiting to be sent out. Try to
+                    // send it again
+                    if (bucket.RemoveTokens(nextPacketLengths[i]))
+                    {
+                        // Send the packet
+                        udpServer.SendPacketFinal(nextPackets[i]);
+                        nextPackets[i] = null;
+                        packetSent = true;
+                    }
+                }
+                else
+                {
+                    // No dequeued packet waiting to be sent, try to pull one off
+                    // this queue
+                    queue = packetOutboxes[i];
+                    if (queue.Dequeue(out packet))
+                    {
+                        // A packet was pulled off the queue. See if we have
+                        // enough tokens in the bucket to send it out
+                        if (bucket.RemoveTokens(packet.Buffer.DataLength))
+                        {
+                            // Send the packet
+                            udpServer.SendPacketFinal(packet);
+                            packetSent = true;
+                        }
+                        else
+                        {
+                            // Save the dequeued packet and the length calculation for
+                            // the next iteration
+                            nextPackets[i] = packet;
+                            nextPacketLengths[i] = packet.Buffer.DataLength;
+                        }
+                    }
+                    else
+                    {
+                        // No packets in this queue. Fire the queue empty callback
+                        QueueEmpty callback = OnQueueEmpty;
+                        if (callback != null)
+                            callback((ThrottleOutPacketType)i);
+                    }
+                }
+            }
+
+            return packetSent;
+        }
+
+        public void UpdateRoundTrip(float r)
+        {
+            const float ALPHA = 0.125f;
+            const float BETA = 0.25f;
+            const float K = 4.0f;
+
+            if (RTTVAR == 0.0f)
+            {
+                // First RTT measurement
+                SRTT = r;
+                RTTVAR = r * 0.5f;
+            }
+            else
+            {
+                // Subsequence RTT measurement
+                RTTVAR = (1.0f - BETA) * RTTVAR + BETA * Math.Abs(SRTT - r);
+                SRTT = (1.0f - ALPHA) * SRTT + ALPHA * r;
+            }
+
+            // Always round retransmission timeout up to two seconds
+            RTO = Math.Max(2000, (int)(SRTT + Math.Max(G, K * RTTVAR)));
+            //Logger.Debug("Setting agent " + this.Agent.FullName + "'s RTO to " + RTO + "ms with an RTTVAR of " +
+            //    RTTVAR + " based on new RTT of " + r + "ms");
+        }
+    }
+}