opensim – Rev 1
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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;
using OpenSim.Framework;
using OpenSim.Framework.Monitoring;
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>
public abstract void PacketReceived(UDPPacketBuffer buffer);
/// <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>Flag to process packets asynchronously or synchronously</summary>
private bool m_asyncPacketHandling;
/// <summary>
/// Are we to use object pool(s) to reduce memory churn when receiving data?
/// </summary>
public bool UsePools { get; protected set; }
/// <summary>
/// Pool to use for handling data. May be null if UsePools = false;
/// </summary>
protected OpenSim.Framework.Pool<UDPPacketBuffer> Pool { get; private set; }
/// <summary>Returns true if the server is currently listening for inbound packets, otherwise false</summary>
public bool IsRunningInbound { get; private set; }
/// <summary>Returns true if the server is currently sending outbound packets, otherwise false</summary>
/// <remarks>If IsRunningOut = false, then any request to send a packet is simply dropped.</remarks>
public bool IsRunningOutbound { get; private set; }
/// <summary>
/// Number of UDP receives.
/// </summary>
public int UdpReceives { get; private set; }
/// <summary>
/// Number of UDP sends
/// </summary>
public int UdpSends { get; private set; }
/// <summary>
/// Number of receives over which to establish a receive time average.
/// </summary>
private readonly static int s_receiveTimeSamples = 500;
/// <summary>
/// Current number of samples taken to establish a receive time average.
/// </summary>
private int m_currentReceiveTimeSamples;
/// <summary>
/// Cumulative receive time for the sample so far.
/// </summary>
private int m_receiveTicksInCurrentSamplePeriod;
/// <summary>
/// The average time taken for each require receive in the last sample.
/// </summary>
public float AverageReceiveTicksForLastSamplePeriod { get; private set; }
/// <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>
/// /// <param name="usePool">Are we to use an object pool to get objects for handing inbound data?</param>
public OpenSimUDPBase(IPAddress bindAddress, int port)
{
m_localBindAddress = bindAddress;
m_udpPort = port;
}
/// <summary>
/// Start inbound UDP packet handling.
/// </summary>
/// <param name="recvBufferSize">The size of the receive buffer for
/// the UDP socket. This value is passed up to the operating system
/// and used in the system networking stack. Use zero to leave this
/// value as the default</param>
/// <param name="asyncPacketHandling">Set this to true to start
/// receiving more packets while current packet handler callbacks are
/// still running. Setting this to false will complete each packet
/// callback before the next packet is processed</param>
/// <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 StartInbound(int recvBufferSize, bool asyncPacketHandling)
{
m_asyncPacketHandling = asyncPacketHandling;
if (!IsRunningInbound)
{
m_log.DebugFormat("[UDPBASE]: Starting inbound UDP loop");
const int SIO_UDP_CONNRESET = -1744830452;
IPEndPoint ipep = new IPEndPoint(m_localBindAddress, m_udpPort);
m_log.DebugFormat(
"[UDPBASE]: Binding UDP listener using internal IP address config {0}:{1}",
ipep.Address, ipep.Port);
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");
}
if (recvBufferSize != 0)
m_udpSocket.ReceiveBufferSize = recvBufferSize;
m_udpSocket.Bind(ipep);
IsRunningInbound = true;
// kick off an async receive. The Start() method will return, the
// actual receives will occur asynchronously and will be caught in
// AsyncEndRecieve().
AsyncBeginReceive();
}
}
/// <summary>
/// Start outbound UDP packet handling.
/// </summary>
public void StartOutbound()
{
m_log.DebugFormat("[UDPBASE]: Starting outbound UDP loop");
IsRunningOutbound = true;
}
public void StopInbound()
{
if (IsRunningInbound)
{
m_log.DebugFormat("[UDPBASE]: Stopping inbound UDP loop");
IsRunningInbound = false;
m_udpSocket.Close();
}
}
public void StopOutbound()
{
m_log.DebugFormat("[UDPBASE]: Stopping outbound UDP loop");
IsRunningOutbound = false;
}
protected virtual bool EnablePools()
{
if (!UsePools)
{
Pool = new Pool<UDPPacketBuffer>(() => new UDPPacketBuffer(), 500);
UsePools = true;
return true;
}
return false;
}
protected virtual bool DisablePools()
{
if (UsePools)
{
UsePools = false;
// We won't null out the pool to avoid a race condition with code that may be in the middle of using it.
return true;
}
return false;
}
private void AsyncBeginReceive()
{
UDPPacketBuffer buf;
// FIXME: Disabled for now as this causes issues with reused packet objects interfering with each other
// on Windows with m_asyncPacketHandling = true, though this has not been seen on Linux.
// Possibly some unexpected issue with fetching UDP data concurrently with multiple threads. Requires more investigation.
// if (UsePools)
// buf = Pool.GetObject();
// else
buf = new UDPPacketBuffer();
if (IsRunningInbound)
{
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 e)
{
m_log.Error(
string.Format("[UDPBASE]: Error processing UDP begin receive {0}. Exception ", UdpReceives), e);
}
catch (Exception e)
{
m_log.Error(
string.Format("[UDPBASE]: Error processing UDP begin receive {0}. Exception ", UdpReceives), e);
}
}
}
private void AsyncEndReceive(IAsyncResult iar)
{
// Asynchronous receive operations will complete here through the call
// to AsyncBeginReceive
if (IsRunningInbound)
{
UdpReceives++;
// Asynchronous mode will start another receive before the
// callback for this packet is even fired. Very parallel :-)
if (m_asyncPacketHandling)
AsyncBeginReceive();
try
{
// get the buffer that was created in AsyncBeginReceive
// this is the received data
UDPPacketBuffer buffer = (UDPPacketBuffer)iar.AsyncState;
int startTick = Util.EnvironmentTickCount();
// 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);
// If more than one thread can be calling AsyncEndReceive() at once (e.g. if m_asyncPacketHandler)
// then a particular stat may be inaccurate due to a race condition. We won't worry about this
// since this should be rare and won't cause a runtime problem.
if (m_currentReceiveTimeSamples >= s_receiveTimeSamples)
{
AverageReceiveTicksForLastSamplePeriod
= (float)m_receiveTicksInCurrentSamplePeriod / s_receiveTimeSamples;
m_receiveTicksInCurrentSamplePeriod = 0;
m_currentReceiveTimeSamples = 0;
}
else
{
m_receiveTicksInCurrentSamplePeriod += Util.EnvironmentTickCountSubtract(startTick);
m_currentReceiveTimeSamples++;
}
}
catch (SocketException se)
{
m_log.Error(
string.Format(
"[UDPBASE]: Error processing UDP end receive {0}, socket error code {1}. Exception ",
UdpReceives, se.ErrorCode),
se);
}
catch (ObjectDisposedException e)
{
m_log.Error(
string.Format("[UDPBASE]: Error processing UDP end receive {0}. Exception ", UdpReceives), e);
}
catch (Exception e)
{
m_log.Error(
string.Format("[UDPBASE]: Error processing UDP end receive {0}. Exception ", UdpReceives), e);
}
finally
{
// if (UsePools)
// Pool.ReturnObject(buffer);
// Synchronous mode waits until the packet callback completes
// before starting the receive to fetch another packet
if (!m_asyncPacketHandling)
AsyncBeginReceive();
}
}
}
public void AsyncBeginSend(UDPPacketBuffer buf)
{
// if (IsRunningOutbound)
// {
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;
m_udpSocket.EndSendTo(result);
UdpSends++;
}
catch (SocketException) { }
catch (ObjectDisposedException) { }
}
}
}
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