/// <summary>
/// Create a TcpStreamGenerator given a flow
/// </summary>
/// <param name="f">
/// A <see cref="TcpFlow"/>
/// </param>
/// <param name="timeout">
/// A <see cref="TimeSpan"/>
/// </param>
/// <param name="sizeLimitInBytes">
/// A <see cref="System.Nullable<System.Int64>"/>
/// </param>
public TcpStreamGenerator(TcpFlow f,
TimeSpan timeout,
long?sizeLimitInBytes)
{
this.flow = f;
this.flow.OnPacketReceived += HandleFlowOnPacketReceived;
this.timeout = timeout;
this.sizeLimitInBytes = sizeLimitInBytes;
packets = new LinkedList <PacketDotNet.TcpPacket>();
tcpStream = new TcpStream();
condition = TcpStreamGenerator.CallbackCondition.NextInSequence;
waiting_for_start_seq = true;
LastContinuousSequence = 0;
last_overall_seq = 0;
// use now as our last packet received time to avoid
// timing this monitor out immediately
last_continuous_packet_received = DateTime.Now;
}
/// <summary>
/// Return a new TcpStream that is the same as the previous stream but has the packets
/// we've already read trimmed off of the list
/// </summary>
/// <returns>
/// A <see cref="TcpStream"/>
/// </returns>
public TcpStream TrimUnusedPackets()
{
#if PERFORMANCE_CRITICAL_LOGGING
log.Debug("");
#endif
// create a new stream
TcpStream newStream = new TcpStream();
// if we have no first packet then we can exit here
if (FirstPacket == null)
{
#if PERFORMANCE_CRITICAL_LOGGING
log.Debug("FirstPacket == null, returning empty TcpStream");
#endif
return(newStream);
}
// copy the first packet variable
newStream._firstPacket = FirstPacket;
LinkedListNode <PacketInfo> currentPacket = GetCurrentPosition();
// special case for when we are at the end of the last packet
// in which case we have nothing to do
if (currentPacket == null)
{
#if PERFORMANCE_CRITICAL_LOGGING
log.Debug("currentPacket == null, returning empty newStream");
#endif
return(newStream);
}
// the offset of the currentPacket is the number of bytes we can discard
long bytesToDiscard = currentPacket.Value.offset;
#if PERFORMANCE_CRITICAL_LOGGING
log.DebugFormat("bytesToDiscard {0}", bytesToDiscard);
#endif
// copy the PacketInfo entries from the current stream to the new one
LinkedListNode <PacketInfo> pos = currentPacket;
while (pos != null)
{
#if PERFORMANCE_CRITICAL_LOGGING
log.DebugFormat("adding packet of size {0}", pos.Value.length);
#endif
// copy the packet info from the current stream
PacketInfo newPacketInfo = new PacketInfo(pos.Value);
// adjust its offset
newPacketInfo.offset -= bytesToDiscard;
// add it to the new stream
newStream.packets.AddLast(newPacketInfo);
#if PERFORMANCE_CRITICAL_LOGGING
log.DebugFormat("newStream.Length {0}", newStream.Length);
#endif
// advance to the next packet in the current stream
pos = pos.Next;
}
#if PERFORMANCE_CRITICAL_LOGGING
log.DebugFormat("after importing all packets newStream.Length {0}", newStream.Length);
#endif
// now write the bytes from the old stream
// NOTE: we cannot use originalBytes.Length because MemoryStream.GetBuffer() returns
// the internal buffer that can be larger than the actual number of bytes in the stream
byte[] originalBytes = base.GetBuffer();
newStream.Write(originalBytes, (int)bytesToDiscard, (int)(base.Length - bytesToDiscard));
// set the proper position in the newStream
#if PERFORMANCE_CRITICAL_LOGGING
log.DebugFormat("base.Position {0}", base.Position);
#endif
newStream.Position = base.Position - bytesToDiscard;
//FIXME: for debugging
#if false
log.DebugFormat("trimmed size from {0} down to {1}, starting packets, {2}, ending packets {3}, removed {4} packets",
base.Length, newStream.Length,
packets.Count, newStream.packets.Count,
(packets.Count - newStream.packets.Count));
log.DebugFormat("original position of {0} is position of {1} in the newStream",
base.Position, newStream.Position);
#endif
return(newStream);
}
