public void HandleReceiveComplete(SNIPacket packet, uint sniErrorCode)
{
using (TrySNIEventScope.Create(nameof(SNIMarsConnection)))
{
if (sniErrorCode != TdsEnums.SNI_SUCCESS)
{
lock (DemuxerSync)
{
HandleReceiveError(packet);
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.ERR, "MARS Session Id {0}, Handled receive error code: {1}", args0: _lowerHandle?.ConnectionId, args1: sniErrorCode);
return;
}
}
State state = State.Demux;
State nextState = State.Demux;
SNISMUXHeader handleHeader = default;
SNIMarsHandle handleSession = null;
SNIPacket handlePacket = null;
while (state != State.Error && state != State.Finish)
{
switch (state)
{
case State.Demux:
lock (DemuxerSync)
{
switch (_demuxState)
{
case DemuxState.Header:
int taken = packet.TakeData(_headerBytes, _headerCount, SNISMUXHeader.HEADER_LENGTH - _headerCount);
_headerCount += taken;
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, took {1} header bytes", args0: _lowerHandle?.ConnectionId, args1: packet.DataLeft, args2: taken);
if (_headerCount == SNISMUXHeader.HEADER_LENGTH)
{
_header.Read(_headerBytes);
_payloadLength = (int)_header.Length;
_payloadCount = 0;
_demuxState = DemuxState.Payload;
state = State.Demux;
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, header complete, _payloadLength {1}", args0: _lowerHandle?.ConnectionId, args1: _payloadLength);
goto case DemuxState.Payload;
}
else
{
state = State.Receive;
}
break;
case DemuxState.Payload:
if (packet.DataLeft == _payloadLength && _partial == null)
{
// if the data in the packet being processed is exactly and only the data that is going to sent
// on to the parser then don't copy it to a new packet just forward the current packet once we've
// fiddled the data pointer so that it skips the header data
_partial = packet;
packet = null;
_partial.SetDataToRemainingContents();
_demuxState = DemuxState.Dispatch;
state = State.Demux;
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, forwarding packet contents", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
goto case DemuxState.Dispatch;
}
else
{
if (_partial == null)
{
_partial = RentPacket(headerSize: 0, dataSize: _payloadLength);
}
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, reconstructing packet contents", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
int wanted = _payloadLength - _payloadCount;
int transferred = SNIPacket.TransferData(packet, _partial, wanted);
_payloadCount += transferred;
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, took {1} payload bytes", args0: _lowerHandle?.ConnectionId, args1: transferred);
if (_payloadCount == _payloadLength)
{
// payload is complete so dispatch the current packet
_demuxState = DemuxState.Dispatch;
state = State.Receive;
goto case DemuxState.Dispatch;
}
else if (packet.DataLeft == 0)
{
// no more data in the delivered packet so wait for a new one
_demuxState = DemuxState.Payload;
state = State.Receive;
}
else
{
// data left in the delivered packet so start the demux loop
// again and decode the next packet in the input
_headerCount = 0;
_demuxState = DemuxState.Header;
state = State.Demux;
}
}
break;
case DemuxState.Dispatch:
if (_sessions.TryGetValue(_header.SessionId, out SNIMarsHandle session))
{
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, Current Session assigned to Session Id {1}", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
switch ((SNISMUXFlags)_header.Flags)
{
case SNISMUXFlags.SMUX_DATA:
handleSession = session;
session = null;
handleHeader = _header.Clone();
handlePacket = _partial;
_partial = null;
// move to the state for sending the data to the mars handle and setup
// the state that should be moved to after that operation has succeeded
state = State.HandleData;
if (packet != null && packet.DataLeft > 0)
{
nextState = State.Demux;
}
else
{
nextState = State.Receive;
}
break;
case SNISMUXFlags.SMUX_ACK:
handleSession = session;
session = null;
handleHeader = _header.Clone();
ReturnPacket(_partial);
_partial = null;
// move to the state for sending the data to the mars handle and setup
// the state that should be moved to after that operation has succeeded
state = State.HandleAck;
if (packet != null && packet.DataLeft > 0)
{
nextState = State.Demux;
}
else
{
nextState = State.Receive;
}
break;
case SNISMUXFlags.SMUX_FIN:
ReturnPacket(_partial);
_partial = null;
_sessions.Remove(_header.SessionId);
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "SMUX_FIN | MARS Session Id {0}, SMUX_FIN flag received, Current Header Session Id {1} removed", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
break;
default:
Debug.Fail("unknown smux packet flag");
break;
}
// a full packet has been decoded and queued for sending by setting the state or the
// handle it was sent to no longer exists and the handle has been dropped. Now reset the
// demuxer state ready to recode another packet
_header.Clear();
_headerCount = 0;
_demuxState = DemuxState.Header;
// if the state is set to demux more data and there is no data left then change
// the state to request more data
if (state == State.Demux && (packet == null || packet.DataLeft == 0))
{
if (packet != null)
{
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, run out of data , queuing receive", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
}
state = State.Receive;
}
}
else
{
SNILoadHandle.SingletonInstance.LastError = new SNIError(SNIProviders.SMUX_PROV, 0, SNICommon.InvalidParameterError, string.Empty);
HandleReceiveError(packet);
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.ERR, "Current Header Session Id {0} not found, MARS Session Id {1} will be destroyed, New SNI error created: {2}", args0: _header.SessionId, args1: _lowerHandle?.ConnectionId, args2: sniErrorCode);
packet = null;
_lowerHandle.Dispose();
_lowerHandle = null;
state = State.Error;
}
break;
}
}
break;
case State.HandleAck:
Debug.Assert(handleSession != null, "dispatching ack to null SNIMarsHandle");
Debug.Assert(!Monitor.IsEntered(DemuxerSync), "do not dispatch ack to session handle while holding the demuxer lock");
try
{
handleSession.HandleAck(handleHeader.Highwater);
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "SMUX_ACK | MARS Session Id {0}, Current Session {1} handled ack", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
}
catch (Exception e)
{
SNICommon.ReportSNIError(SNIProviders.SMUX_PROV, SNICommon.InternalExceptionError, e);
}
finally
{
handleHeader = default;
handleSession = null;
}
state = nextState;
nextState = State.Finish;
break;
case State.HandleData:
Debug.Assert(handleSession != null, "dispatching data to null SNIMarsHandle");
Debug.Assert(handlePacket != null, "dispatching null data to SNIMarsHandle");
Debug.Assert(!Monitor.IsEntered(DemuxerSync), "do not dispatch data to session handle while holding the demuxer lock");
// do not ReturnPacket(handlePacket) the receiver is responsible for returning the packet
// once it has been used because it can take sync and async paths from to the receiver and
// only the reciever can make the decision on when it is completed and can be returned
try
{
handleSession.HandleReceiveComplete(handlePacket, handleHeader);
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "SMUX_DATA | MARS Session Id {0}, Current Session {1} completed receiving Data", args0: _lowerHandle?.ConnectionId, args1: _header.SessionId);
}
finally
{
handleHeader = default;
handleSession = null;
handlePacket = null;
}
state = nextState;
nextState = State.Finish;
break;
case State.Receive:
if (packet != null)
{
Debug.Assert(packet.DataLeft == 0, "loop exit with data remaining");
ReturnPacket(packet);
packet = null;
}
lock (DemuxerSync)
{
uint receiveResult = ReceiveAsync(ref packet);
if (receiveResult == TdsEnums.SNI_SUCCESS_IO_PENDING)
{
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.INFO, "MARS Session Id {0}, SMUX DATA Header SNI Packet received with code {1}", args0: ConnectionId, args1: receiveResult);
packet = null;
}
else
{
HandleReceiveError(packet);
SqlClientEventSource.Log.TrySNITraceEvent(nameof(SNIMarsConnection), EventType.ERR, "MARS Session Id {0}, Handled receive error code: {1}", args0: _lowerHandle?.ConnectionId, args1: receiveResult);
}
}
state = State.Finish;
break;
}
}
}
}
