281 lines
11 KiB
C#
281 lines
11 KiB
C#
/*
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* Copyright (c) 2006, Clutch, Inc.
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* Original Author: Jeff Cesnik
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* All rights reserved.
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*
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* - Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* - Neither the name of the openmetaverse.org nor the names
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* of its contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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using System;
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using System.Net;
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using System.Net.Sockets;
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using System.Threading;
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using log4net;
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namespace OpenMetaverse
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{
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/// <summary>
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/// Base UDP server
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/// </summary>
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public abstract class OpenSimUDPBase
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{
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private static readonly ILog m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
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/// <summary>
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/// This method is called when an incoming packet is received
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/// </summary>
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/// <param name="buffer">Incoming packet buffer</param>
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public abstract void PacketReceived(UDPPacketBuffer buffer);
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/// <summary>UDP port to bind to in server mode</summary>
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protected int m_udpPort;
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/// <summary>Local IP address to bind to in server mode</summary>
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protected IPAddress m_localBindAddress;
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/// <summary>UDP socket, used in either client or server mode</summary>
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private Socket m_udpSocket;
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/// <summary>Flag to process packets asynchronously or synchronously</summary>
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private bool m_asyncPacketHandling;
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/// <summary>The all important shutdown flag</summary>
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private volatile bool m_shutdownFlag = true;
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/// <summary>Returns true if the server is currently listening, otherwise false</summary>
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public bool IsRunning { get { return !m_shutdownFlag; } }
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/// <summary>
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/// Default constructor
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/// </summary>
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/// <param name="bindAddress">Local IP address to bind the server to</param>
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/// <param name="port">Port to listening for incoming UDP packets on</param>
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public OpenSimUDPBase(IPAddress bindAddress, int port)
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{
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m_localBindAddress = bindAddress;
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m_udpPort = port;
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}
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/// <summary>
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/// Start the UDP server
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/// </summary>
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/// <param name="recvBufferSize">The size of the receive buffer for
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/// the UDP socket. This value is passed up to the operating system
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/// and used in the system networking stack. Use zero to leave this
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/// value as the default</param>
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/// <param name="asyncPacketHandling">Set this to true to start
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/// receiving more packets while current packet handler callbacks are
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/// still running. Setting this to false will complete each packet
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/// callback before the next packet is processed</param>
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/// <remarks>This method will attempt to set the SIO_UDP_CONNRESET flag
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/// on the socket to get newer versions of Windows to behave in a sane
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/// manner (not throwing an exception when the remote side resets the
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/// connection). This call is ignored on Mono where the flag is not
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/// necessary</remarks>
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public void Start(int recvBufferSize, bool asyncPacketHandling)
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{
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m_asyncPacketHandling = asyncPacketHandling;
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if (m_shutdownFlag)
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{
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const int SIO_UDP_CONNRESET = -1744830452;
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IPEndPoint ipep = new IPEndPoint(m_localBindAddress, m_udpPort);
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m_udpSocket = new Socket(
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AddressFamily.InterNetwork,
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SocketType.Dgram,
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ProtocolType.Udp);
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try
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{
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// This udp socket flag is not supported under mono,
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// so we'll catch the exception and continue
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m_udpSocket.IOControl(SIO_UDP_CONNRESET, new byte[] { 0 }, null);
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m_log.Debug("[UDPBASE]: SIO_UDP_CONNRESET flag set");
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}
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catch (SocketException)
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{
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m_log.Debug("[UDPBASE]: SIO_UDP_CONNRESET flag not supported on this platform, ignoring");
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}
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if (recvBufferSize != 0)
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m_udpSocket.ReceiveBufferSize = recvBufferSize;
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m_udpSocket.Bind(ipep);
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// we're not shutting down, we're starting up
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m_shutdownFlag = false;
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// kick off an async receive. The Start() method will return, the
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// actual receives will occur asynchronously and will be caught in
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// AsyncEndRecieve().
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AsyncBeginReceive();
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}
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}
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/// <summary>
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/// Stops the UDP server
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/// </summary>
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public void Stop()
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{
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if (!m_shutdownFlag)
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{
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// wait indefinitely for a writer lock. Once this is called, the .NET runtime
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// will deny any more reader locks, in effect blocking all other send/receive
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// threads. Once we have the lock, we set shutdownFlag to inform the other
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// threads that the socket is closed.
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m_shutdownFlag = true;
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m_udpSocket.Close();
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}
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}
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private void AsyncBeginReceive()
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{
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// allocate a packet buffer
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//WrappedObject<UDPPacketBuffer> wrappedBuffer = Pool.CheckOut();
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UDPPacketBuffer buf = new UDPPacketBuffer();
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if (!m_shutdownFlag)
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{
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try
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{
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// kick off an async read
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m_udpSocket.BeginReceiveFrom(
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//wrappedBuffer.Instance.Data,
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buf.Data,
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0,
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UDPPacketBuffer.BUFFER_SIZE,
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SocketFlags.None,
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ref buf.RemoteEndPoint,
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AsyncEndReceive,
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//wrappedBuffer);
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buf);
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}
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catch (SocketException e)
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{
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if (e.SocketErrorCode == SocketError.ConnectionReset)
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{
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m_log.Warn("[UDPBASE]: SIO_UDP_CONNRESET was ignored, attempting to salvage the UDP listener on port " + m_udpPort);
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bool salvaged = false;
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while (!salvaged)
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{
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try
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{
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m_udpSocket.BeginReceiveFrom(
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//wrappedBuffer.Instance.Data,
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buf.Data,
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0,
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UDPPacketBuffer.BUFFER_SIZE,
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SocketFlags.None,
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ref buf.RemoteEndPoint,
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AsyncEndReceive,
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//wrappedBuffer);
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buf);
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salvaged = true;
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}
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catch (SocketException) { }
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catch (ObjectDisposedException) { return; }
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}
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m_log.Warn("[UDPBASE]: Salvaged the UDP listener on port " + m_udpPort);
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}
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}
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catch (ObjectDisposedException) { }
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}
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}
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private void AsyncEndReceive(IAsyncResult iar)
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{
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// Asynchronous receive operations will complete here through the call
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// to AsyncBeginReceive
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if (!m_shutdownFlag)
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{
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// Asynchronous mode will start another receive before the
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// callback for this packet is even fired. Very parallel :-)
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if (m_asyncPacketHandling)
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AsyncBeginReceive();
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// get the buffer that was created in AsyncBeginReceive
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// this is the received data
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//WrappedObject<UDPPacketBuffer> wrappedBuffer = (WrappedObject<UDPPacketBuffer>)iar.AsyncState;
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//UDPPacketBuffer buffer = wrappedBuffer.Instance;
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UDPPacketBuffer buffer = (UDPPacketBuffer)iar.AsyncState;
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try
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{
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// get the length of data actually read from the socket, store it with the
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// buffer
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buffer.DataLength = m_udpSocket.EndReceiveFrom(iar, ref buffer.RemoteEndPoint);
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// call the abstract method PacketReceived(), passing the buffer that
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// has just been filled from the socket read.
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PacketReceived(buffer);
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}
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catch (SocketException) { }
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catch (ObjectDisposedException) { }
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finally
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{
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//wrappedBuffer.Dispose();
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// Synchronous mode waits until the packet callback completes
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// before starting the receive to fetch another packet
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if (!m_asyncPacketHandling)
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AsyncBeginReceive();
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}
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}
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}
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public void AsyncBeginSend(UDPPacketBuffer buf)
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{
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if (!m_shutdownFlag)
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{
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try
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{
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m_udpSocket.BeginSendTo(
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buf.Data,
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0,
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buf.DataLength,
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SocketFlags.None,
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buf.RemoteEndPoint,
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AsyncEndSend,
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buf);
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}
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catch (SocketException) { }
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catch (ObjectDisposedException) { }
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}
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}
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void AsyncEndSend(IAsyncResult result)
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{
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try
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{
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// UDPPacketBuffer buf = (UDPPacketBuffer)result.AsyncState;
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m_udpSocket.EndSendTo(result);
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}
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catch (SocketException) { }
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catch (ObjectDisposedException) { }
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}
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}
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}
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