243 lines
11 KiB
C#
243 lines
11 KiB
C#
/*
|
|
* Copyright (c) Contributors, http://opensimulator.org/
|
|
* See CONTRIBUTORS.TXT for a full list of copyright holders.
|
|
*
|
|
* 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.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* * Neither the name of the OpenSimulator Project 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 DEVELOPERS ``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 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.Collections.Generic;
|
|
using System.Net;
|
|
using System.Threading;
|
|
using OpenMetaverse;
|
|
|
|
//using System.Reflection;
|
|
//using log4net;
|
|
|
|
namespace OpenSim.Region.ClientStack.LindenUDP
|
|
{
|
|
/// <summary>
|
|
/// Special collection that is optimized for tracking unacknowledged packets
|
|
/// </summary>
|
|
public sealed class UnackedPacketCollection
|
|
{
|
|
/// <summary>
|
|
/// Holds information about a pending acknowledgement
|
|
/// </summary>
|
|
private struct PendingAck
|
|
{
|
|
/// <summary>Sequence number of the packet to remove</summary>
|
|
public uint SequenceNumber;
|
|
/// <summary>Environment.TickCount value when the remove was queued.
|
|
/// This is used to update round-trip times for packets</summary>
|
|
public int RemoveTime;
|
|
/// <summary>Whether or not this acknowledgement was attached to a
|
|
/// resent packet. If so, round-trip time will not be calculated</summary>
|
|
public bool FromResend;
|
|
|
|
public PendingAck(uint sequenceNumber, int currentTime, bool fromResend)
|
|
{
|
|
SequenceNumber = sequenceNumber;
|
|
RemoveTime = currentTime;
|
|
FromResend = fromResend;
|
|
}
|
|
}
|
|
|
|
//private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
|
|
|
|
/// <summary>Holds the actual unacked packet data, sorted by sequence number</summary>
|
|
private Dictionary<uint, OutgoingPacket> m_packets = new Dictionary<uint, OutgoingPacket>();
|
|
/// <summary>Holds packets that need to be added to the unacknowledged list</summary>
|
|
private LocklessQueue<OutgoingPacket> m_pendingAdds = new LocklessQueue<OutgoingPacket>();
|
|
/// <summary>Holds information about pending acknowledgements</summary>
|
|
private LocklessQueue<PendingAck> m_pendingAcknowledgements = new LocklessQueue<PendingAck>();
|
|
/// <summary>Holds information about pending removals</summary>
|
|
private LocklessQueue<uint> m_pendingRemoves = new LocklessQueue<uint>();
|
|
|
|
/// <summary>
|
|
/// Add an unacked packet to the collection
|
|
/// </summary>
|
|
/// <param name="packet">Packet that is awaiting acknowledgement</param>
|
|
/// <returns>True if the packet was successfully added, false if the
|
|
/// packet already existed in the collection</returns>
|
|
/// <remarks>This does not immediately add the ACK to the collection,
|
|
/// it only queues it so it can be added in a thread-safe way later</remarks>
|
|
public void Add(OutgoingPacket packet)
|
|
{
|
|
m_pendingAdds.Enqueue(packet);
|
|
Interlocked.Add(ref packet.Client.UnackedBytes, packet.Buffer.DataLength);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Marks a packet as acknowledged
|
|
/// This method is used when an acknowledgement is received from the network for a previously
|
|
/// sent packet. Effects of removal this way are to update unacked byte count, adjust RTT
|
|
/// and increase throttle to the coresponding client.
|
|
/// </summary>
|
|
/// <param name="sequenceNumber">Sequence number of the packet to
|
|
/// acknowledge</param>
|
|
/// <param name="currentTime">Current value of Environment.TickCount</param>
|
|
/// <remarks>This does not immediately acknowledge the packet, it only
|
|
/// queues the ack so it can be handled in a thread-safe way later</remarks>
|
|
public void Acknowledge(uint sequenceNumber, int currentTime, bool fromResend)
|
|
{
|
|
m_pendingAcknowledgements.Enqueue(new PendingAck(sequenceNumber, currentTime, fromResend));
|
|
}
|
|
|
|
/// <summary>
|
|
/// Marks a packet as no longer needing acknowledgement without a received acknowledgement.
|
|
/// This method is called when a packet expires and we no longer need an acknowledgement.
|
|
/// When some reliable packet types expire, they are handled in a way other than simply
|
|
/// resending them. The only effect of removal this way is to update unacked byte count.
|
|
/// </summary>
|
|
/// <param name="sequenceNumber">Sequence number of the packet to
|
|
/// acknowledge</param>
|
|
/// <remarks>The does not immediately remove the packet, it only queues the removal
|
|
/// so it can be handled in a thread safe way later</remarks>
|
|
public void Remove(uint sequenceNumber)
|
|
{
|
|
m_pendingRemoves.Enqueue(sequenceNumber);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Returns a list of all of the packets with a TickCount older than
|
|
/// the specified timeout
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// This function is not thread safe, and cannot be called
|
|
/// multiple times concurrently
|
|
/// </remarks>
|
|
/// <param name="timeoutMS">Number of ticks (milliseconds) before a
|
|
/// packet is considered expired
|
|
/// </param>
|
|
/// <returns>
|
|
/// A list of all expired packets according to the given
|
|
/// expiration timeout
|
|
/// </returns>
|
|
public List<OutgoingPacket> GetExpiredPackets(int timeoutMS)
|
|
{
|
|
ProcessQueues();
|
|
|
|
List<OutgoingPacket> expiredPackets = null;
|
|
|
|
if (m_packets.Count > 0)
|
|
{
|
|
int now = Environment.TickCount & Int32.MaxValue;
|
|
|
|
foreach (OutgoingPacket packet in m_packets.Values)
|
|
{
|
|
// TickCount of zero means a packet is in the resend queue
|
|
// but hasn't actually been sent over the wire yet
|
|
if (packet.TickCount == 0)
|
|
continue;
|
|
|
|
if (now - packet.TickCount >= timeoutMS)
|
|
{
|
|
if (expiredPackets == null)
|
|
expiredPackets = new List<OutgoingPacket>();
|
|
|
|
// The TickCount will be set to the current time when the packet
|
|
// is actually sent out again
|
|
packet.TickCount = 0;
|
|
|
|
// As with other network applications, assume that an expired packet is
|
|
// an indication of some network problem, slow transmission
|
|
packet.Client.FlowThrottle.ExpirePackets(1);
|
|
|
|
expiredPackets.Add(packet);
|
|
}
|
|
}
|
|
}
|
|
|
|
// if (expiredPackets != null)
|
|
// m_log.DebugFormat("[UNACKED PACKET COLLECTION]: Found {0} expired packets on timeout of {1}", expiredPackets.Count, timeoutMS);
|
|
|
|
return expiredPackets;
|
|
}
|
|
|
|
private void ProcessQueues()
|
|
{
|
|
// Process all the pending adds
|
|
OutgoingPacket pendingAdd;
|
|
while (m_pendingAdds.TryDequeue(out pendingAdd))
|
|
if (pendingAdd != null)
|
|
m_packets[pendingAdd.SequenceNumber] = pendingAdd;
|
|
|
|
// Process all the pending removes, including updating statistics and round-trip times
|
|
PendingAck pendingAcknowledgement;
|
|
while (m_pendingAcknowledgements.TryDequeue(out pendingAcknowledgement))
|
|
{
|
|
//m_log.DebugFormat("[UNACKED PACKET COLLECTION]: Processing ack {0}", pendingAcknowledgement.SequenceNumber);
|
|
OutgoingPacket ackedPacket;
|
|
if (m_packets.TryGetValue(pendingAcknowledgement.SequenceNumber, out ackedPacket))
|
|
{
|
|
if (ackedPacket != null)
|
|
{
|
|
m_packets.Remove(pendingAcknowledgement.SequenceNumber);
|
|
|
|
// As with other network applications, assume that an acknowledged packet is an
|
|
// indication that the network can handle a little more load, speed up the transmission
|
|
ackedPacket.Client.FlowThrottle.AcknowledgePackets(1);
|
|
|
|
// Update stats
|
|
Interlocked.Add(ref ackedPacket.Client.UnackedBytes, -ackedPacket.Buffer.DataLength);
|
|
|
|
if (!pendingAcknowledgement.FromResend)
|
|
{
|
|
// Calculate the round-trip time for this packet and its ACK
|
|
int rtt = pendingAcknowledgement.RemoveTime - ackedPacket.TickCount;
|
|
if (rtt > 0)
|
|
ackedPacket.Client.UpdateRoundTrip(rtt);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// m_log.WarnFormat("[UNACKED PACKET COLLECTION]: found null packet for sequence number {0} to ack",
|
|
// pendingAcknowledgement.SequenceNumber);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// m_log.WarnFormat("[UNACKED PACKET COLLECTION]: Could not find packet with sequence number {0} to ack",
|
|
// pendingAcknowledgement.SequenceNumber);
|
|
}
|
|
}
|
|
|
|
uint pendingRemove;
|
|
while(m_pendingRemoves.TryDequeue(out pendingRemove))
|
|
{
|
|
OutgoingPacket removedPacket;
|
|
if (m_packets.TryGetValue(pendingRemove, out removedPacket))
|
|
{
|
|
if (removedPacket != null)
|
|
{
|
|
m_packets.Remove(pendingRemove);
|
|
|
|
// Update stats
|
|
Interlocked.Add(ref removedPacket.Client.UnackedBytes, -removedPacket.Buffer.DataLength);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
} |