Files
opensim/OpenSim/Region/ClientStack/Linden/UDP/OpenSimUDPBase.cs
Justin Clark-Casey (justincc) 5d5ea9234f Stop Mono 3.2.8 from binding a UDP socket to a port already in use.
At least on Mono 3.2.8 (but not under Windows), one can bind multiple UDP sockets to the same port by default.
Different simulators cannot demultiplex each other's messages, so a set of confusing non-obvious errors arise if this occurs.
This change prevents such multiple binding.
2014-11-25 23:23:09 +00:00

427 lines
17 KiB
C#

/*
* 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 virtual 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");
}
// On at least Mono 3.2.8, multiple UDP sockets can bind to the same port by default. At the moment
// we never want two regions to listen on the same port as they cannot demultiplex each other's messages,
// leading to a confusing bug.
// By default, Windows does not allow two sockets to bind to the same port.
m_udpSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, false);
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 virtual void StartOutbound()
{
m_log.DebugFormat("[UDPBASE]: Starting outbound UDP loop");
IsRunningOutbound = true;
}
public virtual void StopInbound()
{
if (IsRunningInbound)
{
m_log.DebugFormat("[UDPBASE]: Stopping inbound UDP loop");
IsRunningInbound = false;
m_udpSocket.Close();
}
}
public virtual void StopOutbound()
{
m_log.DebugFormat("[UDPBASE]: Stopping outbound UDP loop");
IsRunningOutbound = false;
}
public virtual bool EnablePools()
{
if (!UsePools)
{
Pool = new Pool<UDPPacketBuffer>(() => new UDPPacketBuffer(), 500);
UsePools = true;
return true;
}
return false;
}
public 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) { }
}
}
}