Fork UDPBase from libOMV into opensim

OpenSim/Region/ClientStack/LindenUDP/LLUDPServer.cs

@@ -87,7 +87,7 @@ namespace OpenSim.Region.ClientStack.LindenUDP
     /// The LLUDP server for a region. This handles incoming and outgoing
     /// packets for all UDP connections to the region
     /// </summary>
-    public class LLUDPServer : UDPBase
+    public class LLUDPServer : OpenSimUDPBase
     {
         private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
 

OpenSim/Region/ClientStack/LindenUDP/OpenSimUDPBase.cs

@@ -0,0 +1,340 @@
+/*
+ * Copyright (c) 2006, Clutch, Inc.
+ * Original Author: Jeff Cesnik
+ * All rights reserved.
+ *
+ * - 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.
+ * - Neither the name of the openmetaverse.org 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR 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.Net;
+using System.Net.Sockets;
+using System.Threading;
+using OpenMetaverse;
+
+namespace OpenSim.Region.ClientStack.LindenUDP
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public abstract class OpenSimUDPBase
+    {
+        // these abstract methods must be implemented in a derived class to actually do
+        // something with the packets that are sent and received.
+        protected abstract void PacketReceived(UDPPacketBuffer buffer);
+        protected abstract void PacketSent(UDPPacketBuffer buffer, int bytesSent);
+
+        // the port to listen on
+        internal int udpPort;
+
+        // the UDP socket
+        private Socket udpSocket;
+
+        // the ReaderWriterLock is used solely for the purposes of shutdown (Stop()).
+        // since there are potentially many "reader" threads in the internal .NET IOCP
+        // thread pool, this is a cheaper synchronization primitive than using
+        // a Mutex object.  This allows many UDP socket "reads" concurrently - when
+        // Stop() is called, it attempts to obtain a writer lock which will then
+        // wait until all outstanding operations are completed before shutting down.
+        // this avoids the problem of closing the socket with outstanding operations
+        // and trying to catch the inevitable ObjectDisposedException.
+        private ReaderWriterLock rwLock = new ReaderWriterLock();
+
+        // number of outstanding operations.  This is a reference count
+        // which we use to ensure that the threads exit cleanly. Note that
+        // we need this because the threads will potentially still need to process
+        // data even after the socket is closed.
+        private int rwOperationCount = 0;
+
+        // the all important shutdownFlag.  This is synchronized through the ReaderWriterLock.
+        private volatile bool shutdownFlag = true;
+
+        // the remote endpoint to communicate with
+        protected IPEndPoint remoteEndPoint = null;
+
+
+        /// <summary>
+        /// Initialize the UDP packet handler in server mode
+        /// </summary>
+        /// <param name="port">Port to listening for incoming UDP packets on</param>
+        public OpenSimUDPBase(int port)
+        {
+            udpPort = port;
+        }
+
+        /// <summary>
+        /// Initialize the UDP packet handler in client mode
+        /// </summary>
+        /// <param name="endPoint">Remote UDP server to connect to</param>
+        public OpenSimUDPBase(IPEndPoint endPoint)
+        {
+            remoteEndPoint = endPoint;
+            udpPort = 0;
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public void Start()
+        {
+            if (shutdownFlag)
+            {
+                if (remoteEndPoint == null)
+                {
+                    // Server mode
+
+                    // create and bind the socket
+                    IPEndPoint ipep = new IPEndPoint(Settings.BIND_ADDR, udpPort);
+                    udpSocket = new Socket(
+                        AddressFamily.InterNetwork,
+                        SocketType.Dgram,
+                        ProtocolType.Udp);
+                    udpSocket.Bind(ipep);
+                }
+                else
+                {
+                    // Client mode
+                    IPEndPoint ipep = new IPEndPoint(Settings.BIND_ADDR, udpPort);
+                    udpSocket = new Socket(
+                        AddressFamily.InterNetwork,
+                        SocketType.Dgram,
+                        ProtocolType.Udp);
+                    udpSocket.Bind(ipep);
+                    //udpSocket.Connect(remoteEndPoint);
+                }
+
+                // we're not shutting down, we're starting up
+                shutdownFlag = false;
+
+                // kick off an async receive.  The Start() method will return, the
+                // actual receives will occur asynchronously and will be caught in
+                // AsyncEndRecieve().
+                AsyncBeginReceive();
+            }
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public void Stop()
+        {
+            if (!shutdownFlag)
+            {
+                // wait indefinitely for a writer lock.  Once this is called, the .NET runtime
+                // will deny any more reader locks, in effect blocking all other send/receive
+                // threads.  Once we have the lock, we set shutdownFlag to inform the other
+                // threads that the socket is closed.
+                rwLock.AcquireWriterLock(-1);
+                shutdownFlag = true;
+                udpSocket.Close();
+                rwLock.ReleaseWriterLock();
+
+                // wait for any pending operations to complete on other
+                // threads before exiting.
+                const int FORCE_STOP = 100;
+                int i = 0;
+                while (rwOperationCount > 0 && i < FORCE_STOP)
+                {
+                    Thread.Sleep(10);
+                    ++i;
+                }
+
+                if (i >= FORCE_STOP)
+                {
+                    Logger.Log("UDPBase.Stop() forced shutdown while waiting on pending operations",
+                        Helpers.LogLevel.Warning);
+                }
+            }
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public bool IsRunning
+        {
+            get { return !shutdownFlag; }
+        }
+
+        private void AsyncBeginReceive()
+        {
+            // this method actually kicks off the async read on the socket.
+            // we aquire a reader lock here to ensure that no other thread
+            // is trying to set shutdownFlag and close the socket.
+            rwLock.AcquireReaderLock(-1);
+
+            if (!shutdownFlag)
+            {
+                // increment the count of pending operations
+                Interlocked.Increment(ref rwOperationCount);
+
+                // allocate a packet buffer
+                //WrappedObject<UDPPacketBuffer> wrappedBuffer = Pool.CheckOut();
+                UDPPacketBuffer buf = new UDPPacketBuffer();
+
+                try
+                {
+                    // kick off an async read
+                    udpSocket.BeginReceiveFrom(
+                        //wrappedBuffer.Instance.Data,
+                        buf.Data,
+                        0,
+                        UDPPacketBuffer.BUFFER_SIZE,
+                        SocketFlags.None,
+                        //ref wrappedBuffer.Instance.RemoteEndPoint,
+                        ref buf.RemoteEndPoint,
+                        new AsyncCallback(AsyncEndReceive),
+                        //wrappedBuffer);
+                        buf);
+                }
+                catch (SocketException)
+                {
+                    // something bad happened
+                    //Logger.Log(
+                    //    "A SocketException occurred in UDPServer.AsyncBeginReceive()", 
+                    //    Helpers.LogLevel.Error, se);
+
+                    // an error occurred, therefore the operation is void.  Decrement the reference count.
+                    Interlocked.Decrement(ref rwOperationCount);
+                }
+            }
+
+            // we're done with the socket for now, release the reader lock.
+            rwLock.ReleaseReaderLock();
+        }
+
+        private void AsyncEndReceive(IAsyncResult iar)
+        {
+            // Asynchronous receive operations will complete here through the call
+            // to AsyncBeginReceive
+
+            // aquire a reader lock
+            rwLock.AcquireReaderLock(-1);
+
+            if (!shutdownFlag)
+            {
+                // get the buffer that was created in AsyncBeginReceive
+                // this is the received data
+                //WrappedObject<UDPPacketBuffer> wrappedBuffer = (WrappedObject<UDPPacketBuffer>)iar.AsyncState;
+                //UDPPacketBuffer buffer = wrappedBuffer.Instance;
+                UDPPacketBuffer buffer = (UDPPacketBuffer)iar.AsyncState;
+
+                try
+                {
+                    // get the length of data actually read from the socket, store it with the
+                    // buffer
+                    buffer.DataLength = udpSocket.EndReceiveFrom(iar, ref buffer.RemoteEndPoint);
+
+                    // this operation is now complete, decrement the reference count
+                    Interlocked.Decrement(ref rwOperationCount);
+
+                    // we're done with the socket, release the reader lock
+                    rwLock.ReleaseReaderLock();
+
+                    // call the abstract method PacketReceived(), passing the buffer that
+                    // has just been filled from the socket read.
+                    PacketReceived(buffer);
+                }
+                catch (SocketException)
+                {
+                    // an error occurred, therefore the operation is void.  Decrement the reference count.
+                    Interlocked.Decrement(ref rwOperationCount);
+
+                    // we're done with the socket for now, release the reader lock.
+                    rwLock.ReleaseReaderLock();
+                }
+                finally
+                {
+                    // start another receive - this keeps the server going!
+                    AsyncBeginReceive();
+
+                    //wrappedBuffer.Dispose();
+                }
+            }
+            else
+            {
+                // nothing bad happened, but we are done with the operation
+                // decrement the reference count and release the reader lock
+                Interlocked.Decrement(ref rwOperationCount);
+                rwLock.ReleaseReaderLock();
+            }
+        }
+
+        public void AsyncBeginSend(UDPPacketBuffer buf)
+        {
+            rwLock.AcquireReaderLock(-1);
+
+            if (!shutdownFlag)
+            {
+                try
+                {
+                    Interlocked.Increment(ref rwOperationCount);
+                    udpSocket.BeginSendTo(
+                        buf.Data,
+                        0,
+                        buf.DataLength,
+                        SocketFlags.None,
+                        buf.RemoteEndPoint,
+                        new AsyncCallback(AsyncEndSend),
+                        buf);
+                }
+                catch (SocketException)
+                {
+                    //Logger.Log(
+                    //    "A SocketException occurred in UDPServer.AsyncBeginSend()",
+                    //    Helpers.LogLevel.Error, se);
+                }
+            }
+
+            rwLock.ReleaseReaderLock();
+        }
+
+        private void AsyncEndSend(IAsyncResult iar)
+        {
+            rwLock.AcquireReaderLock(-1);
+
+            if (!shutdownFlag)
+            {
+                UDPPacketBuffer buffer = (UDPPacketBuffer)iar.AsyncState;
+
+                try
+                {
+                    int bytesSent = udpSocket.EndSendTo(iar);
+
+                    // note that call to the abstract PacketSent() method - we are passing the number
+                    // of bytes sent in a separate parameter, since we can't use buffer.DataLength which
+                    // is the number of bytes to send (or bytes received depending upon whether this
+                    // buffer was part of a send or a receive).
+                    PacketSent(buffer, bytesSent);
+                }
+                catch (SocketException)
+                {
+                    //Logger.Log(
+                    //    "A SocketException occurred in UDPServer.AsyncEndSend()",
+                    //    Helpers.LogLevel.Error, se);
+                }
+            }
+
+            Interlocked.Decrement(ref rwOperationCount);
+            rwLock.ReleaseReaderLock();
+        }
+    }
+}