/// <summary>
/// Send a null packet (1 byte) to the remotEndPoint. Helps keep the TCP connection alive while ensuring the bandwidth usage is an absolute minimum. If an exception is thrown the connection will be closed.
/// </summary>
protected override void SendNullPacket()
{
try
{
//Only once the connection has been established do we send null packets
if (ConnectionInfo.ConnectionState == ConnectionState.Established)
{
//Multiple threads may try to send packets at the same time so we need this lock to prevent a thread cross talk
lock (sendLocker)
{
if (NetworkComms.LoggingEnabled)
{
NetworkComms.Logger.Trace("Sending null packet to " + ConnectionInfo);
}
//Send a single 0 byte
double maxSendTimePerKB = double.MaxValue;
if (!NetworkComms.DisableConnectionSendTimeouts)
{
if (SendTimesMSPerKBCache.Count > MinNumSendsBeforeConnectionSpecificSendTimeout)
{
maxSendTimePerKB = Math.Max(MinimumMSPerKBSendTimeout, SendTimesMSPerKBCache.CalculateMean() + NumberOfStDeviationsForWriteTimeout * SendTimesMSPerKBCache.CalculateStdDeviation());
}
else
{
maxSendTimePerKB = DefaultMSPerKBSendTimeout;
}
}
#if WINDOWS_PHONE
var stream = socket.OutputStream.AsStreamForWrite();
StreamWriteWithTimeout.Write(new byte[] { 0 }, 1, stream, 1, maxSendTimePerKB, MinSendTimeoutMS);
stream.Flush();
#else
StreamWriteWithTimeout.Write(new byte[] { 0 }, 1, tcpClientNetworkStream, 1, maxSendTimePerKB, MinSendTimeoutMS);
#endif
//Update the traffic time after we have written to netStream
ConnectionInfo.UpdateLastTrafficTime();
}
}
//If the connection is shutdown we should call close
if (ConnectionInfo.ConnectionState == ConnectionState.Shutdown)
{
CloseConnection(false, -8);
}
}
catch (Exception)
{
CloseConnection(true, 19);
}
}
/// <summary>
/// Sends the provided packet to the remote end point
/// </summary>
/// <param name="packet">Packet to send</param>
protected override void SendPacketSpecific(Packet packet)
{
//To keep memory copies to a minimum we send the header and payload in two calls to networkStream.Write
byte[] headerBytes = packet.SerialiseHeader(NetworkComms.InternalFixedSendReceiveOptions);
double maxSendTimePerKB = double.MaxValue;
if (!NetworkComms.DisableConnectionSendTimeouts)
{
if (SendTimesMSPerKBCache.Count > MinNumSendsBeforeConnectionSpecificSendTimeout)
{
maxSendTimePerKB = Math.Max(MinimumMSPerKBSendTimeout, SendTimesMSPerKBCache.CalculateMean() + NumberOfStDeviationsForWriteTimeout * SendTimesMSPerKBCache.CalculateStdDeviation());
}
else
{
maxSendTimePerKB = DefaultMSPerKBSendTimeout;
}
}
if (NetworkComms.LoggingEnabled)
{
NetworkComms.Logger.Debug("Sending a packet of type '" + packet.PacketHeader.PacketType + "' to " +
ConnectionInfo + " containing " + headerBytes.Length.ToString() + " header bytes and " + packet.PacketData.Length.ToString() + " payload bytes. Allowing " +
maxSendTimePerKB.ToString("0.0##") + " ms/KB for send.");
}
DateTime startTime = DateTime.Now;
Stream sendingStream;
#if WINDOWS_PHONE
sendingStream = socket.OutputStream.AsStreamForWrite();
#else
sendingStream = tcpClientNetworkStream;
#endif
double headerWriteTime = StreamWriteWithTimeout.Write(headerBytes, headerBytes.Length, sendingStream, NetworkComms.SendBufferSizeBytes, maxSendTimePerKB, MinSendTimeoutMS);
double dataWriteTime = 0;
if (packet.PacketData.Length > 0)
{
dataWriteTime = packet.PacketData.ThreadSafeStream.CopyTo(sendingStream, packet.PacketData.Start, packet.PacketData.Length, NetworkComms.SendBufferSizeBytes, maxSendTimePerKB, MinSendTimeoutMS);
}
#if WINDOWS_PHONE
sendingStream.Flush();
#endif
//We record each send independantly as if one is considerably larger than
//the other it will provide a much more reliable rate
SendTimesMSPerKBCache.AddValue(headerWriteTime, headerBytes.Length);
SendTimesMSPerKBCache.AddValue(dataWriteTime, packet.PacketData.Length);
SendTimesMSPerKBCache.TrimList(MaxNumSendTimes);
//Correctly dispose the stream if we are finished with it
if (packet.PacketData.ThreadSafeStream.CloseStreamAfterSend)
{
packet.PacketData.ThreadSafeStream.Close();
}
if (NetworkComms.LoggingEnabled)
{
NetworkComms.Logger.Trace(" ... " + ((headerBytes.Length + packet.PacketData.Length) / 1024.0).ToString("0.000") + "KB written to TCP netstream at average of " + (((headerBytes.Length + packet.PacketData.Length) / 1024.0) / (DateTime.Now - startTime).TotalSeconds).ToString("0.000") + "KB/s. Current:" + ((headerWriteTime + dataWriteTime) / 2).ToString("0.00") + " ms/KB, AVG:" + SendTimesMSPerKBCache.CalculateMean().ToString("0.00") + " ms/KB.");
}
#if !WINDOWS_PHONE
if (!tcpClient.Connected)
{
if (NetworkComms.LoggingEnabled)
{
NetworkComms.Logger.Error("TCPClient is not marked as connected after write to networkStream. Possibly indicates a dropped connection.");
}
throw new CommunicationException("TCPClient is not marked as connected after write to networkStream. Possibly indicates a dropped connection.");
}
#endif
}