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/*
* 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 log4net;
namespace OpenMetaverse
{
/// <summary>
/// Base UDP server
/// </summary>
public abstract class OpenSimUDPBase
{
private static readonly ILog m_log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
/// <summary>
/// This method is called when an incoming packet is received
/// </summary>
/// <param name="buffer">Incoming packet buffer</param>
protected abstract void PacketReceived(UDPPacketBuffer buffer);
/// <summary>
/// This method is called when an outgoing packet is sent
/// </summary>
/// <param name="buffer">Outgoing packet buffer</param>
/// <param name="bytesSent">Number of bytes written to the wire</param>
protected abstract void PacketSent(UDPPacketBuffer buffer, int bytesSent);
/// <summary>UDP port to bind to in server mode</summary>
protected int m_udpPort;
/// <summary>Local IP address to bind to in server mode</summary>
protected IPAddress m_localBindAddress;
/// <summary>UDP socket, used in either client or server mode</summary>
private Socket m_udpSocket;
/// <summary>The all important shutdown flag</summary>
private volatile bool m_shutdownFlag = true;
/// <summary>Returns true if the server is currently listening, otherwise false</summary>
public bool IsRunning { get { return !m_shutdownFlag; } }
/// <summary>
/// Default constructor
/// </summary>
/// <param name="bindAddress">Local IP address to bind the server to</param>
/// <param name="port">Port to listening for incoming UDP packets on</param>
public OpenSimUDPBase(IPAddress bindAddress, int port)
{
m_localBindAddress = bindAddress;
m_udpPort = port;
}
/// <summary>
/// Start the UDP server
/// </summary>
/// <remarks>This method will attempt to set the SIO_UDP_CONNRESET flag
/// on the socket to get newer versions of Windows to behave in a sane
/// manner (not throwing an exception when the remote side resets the
/// connection). This call is ignored on Mono where the flag is not
/// necessary</remarks>
public void Start()
{
if (m_shutdownFlag)
{
const int SIO_UDP_CONNRESET = -1744830452;
IPEndPoint ipep = new IPEndPoint(m_localBindAddress, m_udpPort);
m_udpSocket = new Socket(
AddressFamily.InterNetwork,
SocketType.Dgram,
ProtocolType.Udp);
try
{
// this udp socket flag is not supported under mono,
// so we'll catch the exception and continue
m_udpSocket.IOControl(SIO_UDP_CONNRESET, new byte[] { 0 }, null);
m_log.Debug("[UDPBASE]: SIO_UDP_CONNRESET flag set");
}
catch (SocketException)
{
m_log.Debug("[UDPBASE]: SIO_UDP_CONNRESET flag not supported on this platform, ignoring");
}
m_udpSocket.Bind(ipep);
// we're not shutting down, we're starting up
m_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>
/// Stops the UDP server
/// </summary>
public void Stop()
{
if (!m_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.
m_shutdownFlag = true;
m_udpSocket.Close();
}
}
private void AsyncBeginReceive()
{
// allocate a packet buffer
//WrappedObject<UDPPacketBuffer> wrappedBuffer = Pool.CheckOut();
UDPPacketBuffer buf = new UDPPacketBuffer();
if (!m_shutdownFlag)
{
try
{
// kick off an async read
m_udpSocket.BeginReceiveFrom(
//wrappedBuffer.Instance.Data,
buf.Data,
0,
UDPPacketBuffer.BUFFER_SIZE,
SocketFlags.None,
ref buf.RemoteEndPoint,
AsyncEndReceive,
//wrappedBuffer);
buf);
}
catch (SocketException e)
{
if (e.SocketErrorCode == SocketError.ConnectionReset)
{
m_log.Warn("[UDPBASE]: SIO_UDP_CONNRESET was ignored, attempting to salvage the UDP listener on port " + m_udpPort);
bool salvaged = false;
while (!salvaged)
{
try
{
m_udpSocket.BeginReceiveFrom(
//wrappedBuffer.Instance.Data,
buf.Data,
0,
UDPPacketBuffer.BUFFER_SIZE,
SocketFlags.None,
ref buf.RemoteEndPoint,
AsyncEndReceive,
//wrappedBuffer);
buf);
salvaged = true;
}
catch (SocketException) { }
catch (ObjectDisposedException) { return; }
}
m_log.Warn("[UDPBASE]: Salvaged the UDP listener on port " + m_udpPort);
}
}
catch (ObjectDisposedException) { }
}
}
private void AsyncEndReceive(IAsyncResult iar)
{
// Asynchronous receive operations will complete here through the call
// to AsyncBeginReceive
if (!m_shutdownFlag)
{
// start another receive - this keeps the server going!
AsyncBeginReceive();
// 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 = m_udpSocket.EndReceiveFrom(iar, ref buffer.RemoteEndPoint);
// call the abstract method PacketReceived(), passing the buffer that
// has just been filled from the socket read.
PacketReceived(buffer);
}
catch (SocketException) { }
catch (ObjectDisposedException) { }
//finally { wrappedBuffer.Dispose(); }
}
}
public void AsyncBeginSend(UDPPacketBuffer buf)
{
if (!m_shutdownFlag)
{
try
{
m_udpSocket.BeginSendTo(
buf.Data,
0,
buf.DataLength,
SocketFlags.None,
buf.RemoteEndPoint,
AsyncEndSend,
buf);
}
catch (SocketException) { }
catch (ObjectDisposedException) { }
}
}
void AsyncEndSend(IAsyncResult result)
{
try
{
UDPPacketBuffer buf = (UDPPacketBuffer)result.AsyncState;
int bytesSent = m_udpSocket.EndSendTo(result);
PacketSent(buf, bytesSent);
}
catch (SocketException) { }
catch (ObjectDisposedException) { }
}
}
}
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