jack2/common/JackNetInterface.cpp

/*
Copyright (C) 2001 Paul Davis
Copyright (C) 2008 Romain Moret at Grame

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "JackNetInterface.h"
#include "JackException.h"
#include "JackPlatformPlug.h"
#include <assert.h>

using namespace std;

#define PACKET_AVAILABLE_SIZE (fParams.fMtu - sizeof(packet_header_t))
#define HEADER_SIZE (sizeof(packet_header_t))

/*  
 TODO : since midi buffers now uses up to BUFFER_SIZE_MAX frames, 
 probably also use BUFFER_SIZE_MAX in everything related to MIDI events 
 handling (see MidiBufferInit in JackMidiPort.cpp)
*/

namespace Jack
{
    // JackNetInterface*******************************************

    JackNetInterface::JackNetInterface() : fSocket()
    {
        Initialize();
    }

    JackNetInterface::JackNetInterface ( const char* multicast_ip, int port ) : fSocket ( multicast_ip, port )
    {
        strcpy(fMulticastIP, multicast_ip);
        Initialize();
    }

    JackNetInterface::JackNetInterface ( session_params_t& params, JackNetSocket& socket, const char* multicast_ip ) : fSocket ( socket )
    {
        fParams = params;
        strcpy(fMulticastIP, multicast_ip);
        Initialize();
    }
    
    void JackNetInterface::Initialize()
    {
        fTxBuffer = NULL;
        fRxBuffer = NULL;
        fNetAudioCaptureBuffer = NULL;
        fNetAudioPlaybackBuffer = NULL;
        fNetMidiCaptureBuffer = NULL;
        fNetMidiPlaybackBuffer = NULL;
        memset(&fSendTransportData, 0, sizeof(net_transport_data_t));
        memset(&fReturnTransportData, 0, sizeof(net_transport_data_t));
    }
    
    void JackNetInterface::FreeNetworkBuffers()
    {
        delete fNetMidiCaptureBuffer;
        delete fNetMidiPlaybackBuffer;
        delete fNetAudioCaptureBuffer;
        delete fNetAudioPlaybackBuffer;
        fNetMidiCaptureBuffer = NULL;
        fNetMidiPlaybackBuffer = NULL;
        fNetAudioCaptureBuffer = NULL;
        fNetAudioPlaybackBuffer = NULL;
    }
    
    JackNetInterface::~JackNetInterface()
    {
        jack_log ("JackNetInterface::~JackNetInterface");

        fSocket.Close();
        delete[] fTxBuffer;
        delete[] fRxBuffer;
        delete fNetAudioCaptureBuffer;
        delete fNetAudioPlaybackBuffer;
        delete fNetMidiCaptureBuffer;
        delete fNetMidiPlaybackBuffer;
    }

    int JackNetInterface::SetNetBufferSize()
    {
        //audio
        float audio_size = (fNetAudioCaptureBuffer) 
                            ? fNetAudioCaptureBuffer->GetCycleSize() 
                            : (fNetAudioPlaybackBuffer) ? fNetAudioPlaybackBuffer->GetCycleSize() : 0;
        jack_log ("audio_size %f", audio_size);
        
        //midi
        float midi_size = (fNetMidiCaptureBuffer) 
                            ? fNetMidiCaptureBuffer->GetCycleSize() 
                            : (fNetMidiPlaybackBuffer) ? fNetMidiPlaybackBuffer->GetCycleSize() : 0;
        jack_log ("midi_size %f", midi_size);
                                     
        //bufsize = sync + audio + midi
        int bufsize = MAX_LATENCY * (fParams.fMtu + (int)audio_size + (int) midi_size);
        jack_log("SetNetBufferSize bufsize = %d", bufsize);

        //tx buffer
        if (fSocket.SetOption(SOL_SOCKET, SO_SNDBUF, &bufsize, sizeof(bufsize)) == SOCKET_ERROR)
            return SOCKET_ERROR;

        //rx buffer
        if (fSocket.SetOption(SOL_SOCKET, SO_RCVBUF, &bufsize, sizeof(bufsize)) == SOCKET_ERROR)
            return SOCKET_ERROR;

        return 0;
    }

    bool JackNetInterface::SetParams()
    {
        //TX header init
        strcpy ( fTxHeader.fPacketType, "header" );
        fTxHeader.fID = fParams.fID;
        fTxHeader.fCycle = 0;
        fTxHeader.fSubCycle = 0;
        fTxHeader.fBitdepth = fParams.fBitdepth;
        fTxHeader.fIsLastPckt = 0;

        //RX header init
        strcpy ( fRxHeader.fPacketType, "header" );
        fRxHeader.fID = fParams.fID;
        fRxHeader.fCycle = 0;
        fRxHeader.fSubCycle = 0;
        fRxHeader.fBitdepth = fParams.fBitdepth;
        fRxHeader.fIsLastPckt = 0;

        //network buffers
        fTxBuffer = new char[fParams.fMtu];
        fRxBuffer = new char[fParams.fMtu];
        assert ( fTxBuffer );
        assert ( fRxBuffer );

        //net audio/midi buffers'addresses
        fTxData = fTxBuffer + HEADER_SIZE;
        fRxData = fRxBuffer + HEADER_SIZE;
        
        return true;
    }

    // JackNetMasterInterface ************************************************************************************

    bool JackNetMasterInterface::Init()
    {
        jack_log ( "JackNetMasterInterface::Init, ID %u.", fParams.fID );

        session_params_t host_params;
        uint attempt = 0;
        int rx_bytes = 0;

        //socket
        if ( fSocket.NewSocket() == SOCKET_ERROR ) {
            jack_error ( "Can't create socket : %s", StrError ( NET_ERROR_CODE ) );
            return false;
        }

        //timeout on receive (for init)
        if ( fSocket.SetTimeOut ( MASTER_INIT_TIMEOUT ) < 0 )
            jack_error ( "Can't set timeout : %s", StrError ( NET_ERROR_CODE ) );
            
        //connect
        if ( fSocket.Connect() == SOCKET_ERROR ) {
            jack_error ( "Can't connect : %s", StrError ( NET_ERROR_CODE ) );
            return false;
        }

        //send 'SLAVE_SETUP' until 'START_MASTER' received
        jack_info ( "Sending parameters to %s...", fParams.fSlaveNetName );
        do
        {
            session_params_t net_params;
            memset(&net_params, 0, sizeof ( session_params_t ));
            SetPacketType ( &fParams, SLAVE_SETUP );
            SessionParamsHToN(&fParams, &net_params);
            
            if ( fSocket.Send ( &net_params, sizeof ( session_params_t ), 0 ) == SOCKET_ERROR )
                jack_error ( "Error in send : ", StrError ( NET_ERROR_CODE ) );
                
            memset(&net_params, 0, sizeof (session_params_t));
            if (((rx_bytes = fSocket.Recv(&net_params, sizeof(session_params_t), 0)) == SOCKET_ERROR) && (fSocket.GetError() != NET_NO_DATA))
            {
                jack_error ( "Problem with network." );
                return false;
            }
            
            SessionParamsNToH(&net_params, &host_params);
        }
        while ( ( GetPacketType ( &host_params ) != START_MASTER ) && ( ++attempt < SLAVE_SETUP_RETRY ) );
        if ( attempt == SLAVE_SETUP_RETRY ) {
            jack_error ( "Slave doesn't respond, exiting." );
            return false;
        }

        return true;
    }

    int JackNetMasterInterface::SetRxTimeout()
    {
        jack_log ( "JackNetMasterInterface::SetRxTimeout" );

        float time = 0;
        
        //slow or normal mode, short timeout on recv (2 audio subcycles)
        if ((fParams.fNetworkMode == 's') || (fParams.fNetworkMode == 'n')) {
            time = 2000000.f * ((fNetAudioCaptureBuffer) 
                                ? fNetAudioCaptureBuffer->GetCycleDuration() 
                                : (fNetAudioPlaybackBuffer) ? fNetAudioPlaybackBuffer->GetCycleDuration() : 0);
        }
        //fast mode, wait for 75% of the entire cycle duration
        else if (fParams.fNetworkMode == 'f') {
            time = 750000.f * (static_cast<float>(fParams.fPeriodSize) / static_cast<float>(fParams.fSampleRate));
        }
        
        return fSocket.SetTimeOut (static_cast<int>(time));
    }

    bool JackNetMasterInterface::SetParams()
    {
        jack_log ( "JackNetMasterInterface::SetParams" );

        JackNetInterface::SetParams();

        fTxHeader.fDataStream = 's';
        fRxHeader.fDataStream = 'r';

        //midi net buffers
        fNetMidiCaptureBuffer = new NetMidiBuffer ( &fParams, fParams.fSendMidiChannels, fTxData );
        fNetMidiPlaybackBuffer = new NetMidiBuffer ( &fParams, fParams.fReturnMidiChannels, fRxData );
        assert ( fNetMidiCaptureBuffer );
        assert ( fNetMidiPlaybackBuffer );

        try {
        //audio net buffers
    #ifdef CELT
            if (fParams.fSendAudioChannels)
                fNetAudioCaptureBuffer = new NetCeltAudioBuffer ( &fParams, fParams.fSendAudioChannels, fTxData );
                
            if (fParams.fReturnAudioChannels)
                fNetAudioPlaybackBuffer = new NetCeltAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fRxData );
            
            //fNetAudioCaptureBuffer = new NetIntAudioBuffer ( &fParams, fParams.fSendAudioChannels, fTxData );
            //fNetAudioPlaybackBuffer = new NetIntAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fRxData );
    #else
            fNetAudioCaptureBuffer = new NetFloatAudioBuffer ( &fParams, fParams.fSendAudioChannels, fTxData );
            fNetAudioPlaybackBuffer = new NetFloatAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fRxData );
    #endif    
    
            //fNetAudioCaptureBuffer = new NetBufferedAudioBuffer ( &fParams, fParams.fSendAudioChannels, fTxData );
            //fNetAudioPlaybackBuffer = new NetBufferedAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fRxData );     
     
        } catch (exception&) {
            jack_error("NetAudioBuffer allocation error...");
            return false;
        }
       
        //set the new timeout for the socket
        if (SetRxTimeout() == SOCKET_ERROR) {
            jack_error("Can't set rx timeout : %s", StrError(NET_ERROR_CODE));
            goto error;
        }

        //set the new rx buffer size
        if (SetNetBufferSize() == SOCKET_ERROR) {
            jack_error("Can't set net buffer sizes : %s", StrError(NET_ERROR_CODE));
            goto error;
        }
        
        return true;
            
    error:
        FreeNetworkBuffers();
        return false;
    }

    void JackNetMasterInterface::Exit()
    {
        jack_log ( "JackNetMasterInterface::Exit, ID %u", fParams.fID );

        //stop process
        fRunning = false;

        //send a 'multicast euthanasia request' - new socket is required on macosx
        jack_info ( "Exiting '%s'", fParams.fName );
        SetPacketType ( &fParams, KILL_MASTER );
        JackNetSocket mcast_socket ( fMulticastIP, fSocket.GetPort() );
        
        session_params_t net_params;
        memset(&net_params, 0, sizeof ( session_params_t ));
        SessionParamsHToN(&fParams, &net_params);

        if ( mcast_socket.NewSocket() == SOCKET_ERROR )
            jack_error ( "Can't create socket : %s", StrError ( NET_ERROR_CODE ) );
        if ( mcast_socket.SendTo ( &net_params, sizeof ( session_params_t ), 0, fMulticastIP ) == SOCKET_ERROR )
            jack_error ( "Can't send suicide request : %s", StrError ( NET_ERROR_CODE ) );
            
        mcast_socket.Close();
    }

    int JackNetMasterInterface::Recv(size_t size, int flags)
    {
        int rx_bytes;
        
        if ((( rx_bytes = fSocket.Recv(fRxBuffer, size, flags)) == SOCKET_ERROR) && fRunning) {
            net_error_t error = fSocket.GetError();
            //no data isn't really a network error, so just return 0 available read bytes
            if (error == NET_NO_DATA) {
                return 0;
            } else if (error == NET_CONN_ERROR) {
                //fatal connection issue, exit
                jack_error ( "'%s' : %s, exiting.", fParams.fName, StrError(NET_ERROR_CODE));
                //ask to the manager to properly remove the master
                Exit();
                
                // UGLY temporary way to be sure the thread does not call code possibly causing a deadlock in JackEngine.
                ThreadExit();
            } else {
                jack_error ( "Error in master receive : %s", StrError(NET_ERROR_CODE));
            }
        }
        
        packet_header_t* header = reinterpret_cast<packet_header_t*>(fRxBuffer);
        PacketHeaderNToH(header, header);
        return rx_bytes;
    }
    
    int JackNetMasterInterface::Send(size_t size, int flags)
    {
        int tx_bytes;
        packet_header_t* header = reinterpret_cast<packet_header_t*>(fTxBuffer);
        PacketHeaderHToN(header, header);
        
        if (((tx_bytes = fSocket.Send(fTxBuffer, size, flags)) == SOCKET_ERROR) && fRunning) {
            net_error_t error = fSocket.GetError();
            if (error == NET_CONN_ERROR) {
                //fatal connection issue, exit
                jack_error ("'%s' : %s, exiting.", fParams.fName, StrError (NET_ERROR_CODE));
                Exit();
                
                // UGLY temporary way to be sure the thread does not call code possibly causing a deadlock in JackEngine.
                ThreadExit();
            } else {
                jack_error("Error in master send : %s", StrError(NET_ERROR_CODE));
            }
        }
        return tx_bytes;
    }
    
    bool JackNetMasterInterface::IsSynched()
    {
        if (fParams.fNetworkMode == 's') {
            return (fCycleOffset < (CYCLE_OFFSET_SLOW + 1));
        } else {
            return true;
        }
    }
    
    int JackNetMasterInterface::SyncSend()
    {
        fTxHeader.fCycle++;
        fTxHeader.fSubCycle = 0;
        fTxHeader.fDataType = 's';
        fTxHeader.fIsLastPckt = (fParams.fSendMidiChannels == 0 && fParams.fSendAudioChannels == 0) ?  1 : 0;
        fTxHeader.fPacketSize = HEADER_SIZE;
        
        memcpy(fTxBuffer, &fTxHeader, HEADER_SIZE);
        return Send(fTxHeader.fPacketSize, 0);
    }

    int JackNetMasterInterface::DataSend()
    {
        uint subproc;
        uint data_size; 
        
        //midi
        if (fParams.fSendMidiChannels > 0)
        {
            //set global header fields and get the number of midi packets
            fTxHeader.fDataType = 'm';
            data_size = fNetMidiCaptureBuffer->RenderFromJackPorts();
            fTxHeader.fNumPacket = fNetMidiCaptureBuffer->GetNumPackets();
            
            for ( subproc = 0; subproc < fTxHeader.fNumPacket; subproc++ )
            {
                fTxHeader.fSubCycle = subproc;
                fTxHeader.fIsLastPckt = ((subproc == (fTxHeader.fNumPacket - 1)) && (fParams.fSendAudioChannels == 0)) ? 1 : 0;
                fTxHeader.fPacketSize = HEADER_SIZE + fNetMidiCaptureBuffer->RenderToNetwork(subproc, data_size);
                memcpy ( fTxBuffer, &fTxHeader, HEADER_SIZE);
                if (Send (fTxHeader.fPacketSize, 0) == SOCKET_ERROR)
                    return SOCKET_ERROR;
            }
        }

        //audio
        if (fParams.fSendAudioChannels > 0)
        {
            fTxHeader.fDataType = 'a';
            data_size = fNetAudioCaptureBuffer->RenderFromJackPorts();
            fTxHeader.fNumPacket = fNetAudioCaptureBuffer->GetNumPackets();
            
            for (subproc = 0; subproc < fTxHeader.fNumPacket; subproc++)
            {
                fTxHeader.fSubCycle = subproc;
                fTxHeader.fIsLastPckt = (subproc == (fTxHeader.fNumPacket - 1)) ? 1 : 0;
                fTxHeader.fPacketSize = HEADER_SIZE + fNetAudioCaptureBuffer->RenderToNetwork(subproc, data_size);
                memcpy(fTxBuffer, &fTxHeader, HEADER_SIZE);
                if (Send(fTxHeader.fPacketSize, 0) == SOCKET_ERROR)
                    return SOCKET_ERROR;
            }
        }

        return 0;
    }
    
    int JackNetMasterInterface::SyncRecv()
    {
        packet_header_t* rx_head = reinterpret_cast<packet_header_t*> ( fRxBuffer );
        int rx_bytes = Recv(HEADER_SIZE, MSG_PEEK);
        
        if ( ( rx_bytes == 0 ) || ( rx_bytes == SOCKET_ERROR ) )
            return rx_bytes;

        fCycleOffset = fTxHeader.fCycle - rx_head->fCycle;
      
        switch ( fParams.fNetworkMode )
        {
            case 's' :
                //slow mode : allow to use full bandwidth and heavy process on the slave
                //  - extra latency is set to two cycles, one cycle for send/receive operations + one cycle for heavy process on the slave
                //  - if the network is two fast, just wait the next cycle, this mode allows a shorter cycle duration for the master
                //  - this mode will skip the two first cycles, thus it lets time for data to be processed and queued on the socket rx buffer
                //the slow mode is the safest mode because it wait twice the bandwidth relative time (send/return + process)
                
                /*
                if (fCycleOffset < CYCLE_OFFSET_SLOW) {
                    return 0;
                } else {
                    rx_bytes = Recv ( rx_head->fPacketSize, 0 );
                }
                */
                
                rx_bytes = Recv ( rx_head->fPacketSize, 0 );
                
                if (fCycleOffset != fLastfCycleOffset)
                    jack_info("Warning : '%s' runs in slow network mode, but data received too late (%d cycle(s) offset)", fParams.fName, fCycleOffset);
                fLastfCycleOffset = fCycleOffset;
                break;

            case 'n' :
                //normal use of the network :
                //  - extra latency is set to one cycle, what is the time needed to receive streams using full network bandwidth
                //  - if the network is too fast, just wait the next cycle, the benefit here is the master's cycle is shorter
                //  - indeed, data is supposed to be on the network rx buffer, so we don't have to wait for it
                if (fCycleOffset < CYCLE_OFFSET_NORMAL) {
                    return 0;
                } else {
                    rx_bytes = Recv ( rx_head->fPacketSize, 0 );
                }
                    
                if (fCycleOffset > CYCLE_OFFSET_NORMAL)  {
                    jack_info("'%s' can't run in normal network mode, data received too late (%d cycle(s) offset)", fParams.fName, fCycleOffset);
                }
                break;

            case 'f' :
                //fast mode suppose the network bandwith is larger than required for the transmission (only a few channels for example)
                //    - packets can be quickly received, quickly is here relative to the cycle duration
                //    - here, receive data, we can't keep it queued on the rx buffer,
                //    - but if there is a cycle offset, tell the user, that means we're not in fast mode anymore, network is too slow
                rx_bytes = Recv ( rx_head->fPacketSize, 0 );
                
                if (fCycleOffset > CYCLE_OFFSET_FAST) {
                    jack_info("'%s' can't run in fast network mode, data received too late (%d cycle(s) offset)", fParams.fName, fCycleOffset);
                }
                break;
        }

        fRxHeader.fIsLastPckt = rx_head->fIsLastPckt;
        return rx_bytes;
    }
    
    int JackNetMasterInterface::DataRecv()
    {
        int rx_bytes = 0;
        uint recvd_midi_pckt = 0;
        uint recvd_audio_pckt = 0;
      
        packet_header_t* rx_head = reinterpret_cast<packet_header_t*> ( fRxBuffer );
        
        while ( !fRxHeader.fIsLastPckt )
        {
            //how much data is queued on the rx buffer ?
            rx_bytes = Recv(HEADER_SIZE, MSG_PEEK);
              
            //error here, problem with recv, just skip the cycle (return -1)
            if ( rx_bytes == SOCKET_ERROR )
                return rx_bytes;
          
            if ( rx_bytes && ( rx_head->fDataStream == 'r' ) && ( rx_head->fID == fParams.fID ) )
            {
                //read data
                switch ( rx_head->fDataType )
                {
                    case 'm':   //midi
                        rx_bytes = Recv(rx_head->fPacketSize, 0);
                        fRxHeader.fCycle = rx_head->fCycle;
                        fRxHeader.fIsLastPckt = rx_head->fIsLastPckt;
                        fNetMidiPlaybackBuffer->RenderFromNetwork(rx_head->fSubCycle, rx_bytes - HEADER_SIZE);
                        // Last midi packet is received, so finish rendering...
                        if (++recvd_midi_pckt == rx_head->fNumPacket)
                            fNetMidiPlaybackBuffer->RenderToJackPorts();
                        break;

                    case 'a':   //audio
                        rx_bytes = Recv(rx_head->fPacketSize, 0);
                        fRxHeader.fCycle = rx_head->fCycle;
                        fRxHeader.fSubCycle = rx_head->fSubCycle;
                        fRxHeader.fIsLastPckt = rx_head->fIsLastPckt;
                        fNetAudioPlaybackBuffer->RenderFromNetwork (rx_head->fCycle, rx_head->fSubCycle, rx_bytes - HEADER_SIZE);
                        // Last audio packet is received, so finish rendering...
                        if (fRxHeader.fIsLastPckt)
                            fNetAudioPlaybackBuffer->RenderToJackPorts();
                        break;

                    case 's':   //sync
                        jack_info("NetMaster : overloaded, skipping receive from '%s'", fParams.fName);
                        // TODO : finish midi and audio rendering ?
                        fNetAudioPlaybackBuffer->RenderToJackPorts();
                        return 0;
                }
            }
        }
 
        return rx_bytes;
    }
    
    void JackNetMasterInterface::EncodeSyncPacket()
    {
        //this method contains every step of sync packet informations coding
        //first of all, reset sync packet
        memset ( fTxData, 0, PACKET_AVAILABLE_SIZE );

        //then, first step : transport
        if (fParams.fTransportSync) {
            EncodeTransportData();
            TransportDataHToN( &fSendTransportData,  &fSendTransportData);
            //copy to TxBuffer
            memcpy ( fTxData, &fSendTransportData, sizeof ( net_transport_data_t ) );
        }
        //then others (freewheel etc.)
        //...
    }

    void JackNetMasterInterface::DecodeSyncPacket()
    {
        //this method contains every step of sync packet informations decoding process
        //first : transport
        if (fParams.fTransportSync) {
            //copy received transport data to transport data structure
            memcpy ( &fReturnTransportData, fRxData, sizeof ( net_transport_data_t ) );
            TransportDataNToH( &fReturnTransportData,  &fReturnTransportData);
            DecodeTransportData();
        }
        //then others
        //...
    }

// JackNetSlaveInterface ************************************************************************************************

    uint JackNetSlaveInterface::fSlaveCounter = 0;

    bool JackNetSlaveInterface::Init()
    {
        jack_log ( "JackNetSlaveInterface::Init()" );

        //set the parameters to send
        strcpy ( fParams.fPacketType, "params" );
        fParams.fProtocolVersion = SLAVE_PROTOCOL;
        SetPacketType ( &fParams, SLAVE_AVAILABLE );

        //init loop : get a master and start, do it until connection is ok
        net_status_t status;
        do
        {
            //first, get a master, do it until a valid connection is running
            do
            {
                status = SendAvailableToMaster();
                if ( status == NET_SOCKET_ERROR )
                    return false;
            }
            while ( status != NET_CONNECTED );

            //then tell the master we are ready
            jack_info ( "Initializing connection with %s...", fParams.fMasterNetName );
            status = SendStartToMaster();
            if ( status == NET_ERROR )
                return false;
        }
        while ( status != NET_ROLLING );

        return true;
    }
    
    // Separate the connection protocol into two separated step
    
    bool JackNetSlaveInterface::InitConnection(int time_out)
    {
        jack_log("JackNetSlaveInterface::InitConnection()");
        int try_count = (time_out > 0) ? ((1000000 * time_out) / SLAVE_INIT_TIMEOUT) : LONG_MAX;
   
        //set the parameters to send
        strcpy (fParams.fPacketType, "params");
        fParams.fProtocolVersion = SLAVE_PROTOCOL;
        SetPacketType (&fParams, SLAVE_AVAILABLE);

        net_status_t status;
        do
        {
            //get a master
            status = SendAvailableToMaster(try_count);
            if (status == NET_SOCKET_ERROR)
                return false;
        }
        while (status != NET_CONNECTED && --try_count > 0);
  
        return (try_count != 0);
    }
    
    bool JackNetSlaveInterface::InitRendering()
    {
        jack_log("JackNetSlaveInterface::InitRendering()");

        net_status_t status;
        do
        {
            //then tell the master we are ready
            jack_info("Initializing connection with %s...", fParams.fMasterNetName);
            status = SendStartToMaster();
            if (status == NET_ERROR)
                return false;
        }
        while (status != NET_ROLLING);   
        
        return true;
    }

    net_status_t JackNetSlaveInterface::SendAvailableToMaster(long try_count)
    {
        jack_log ( "JackNetSlaveInterface::SendAvailableToMaster()" );
        //utility
        session_params_t host_params;
        int rx_bytes = 0;
     
        //socket
        if ( fSocket.NewSocket() == SOCKET_ERROR ) {
            jack_error ( "Fatal error : network unreachable - %s", StrError ( NET_ERROR_CODE ) );
            return NET_SOCKET_ERROR;
        }

        //bind the socket
        if ( fSocket.Bind() == SOCKET_ERROR ) {
            jack_error ( "Can't bind the socket : %s", StrError ( NET_ERROR_CODE ) );
            return NET_SOCKET_ERROR;
        }

        //timeout on receive
        if ( fSocket.SetTimeOut ( SLAVE_INIT_TIMEOUT ) == SOCKET_ERROR ) 
            jack_error ( "Can't set timeout : %s", StrError ( NET_ERROR_CODE ) );

        //disable local loop
        if ( fSocket.SetLocalLoop() == SOCKET_ERROR )
            jack_error ( "Can't disable multicast loop : %s", StrError ( NET_ERROR_CODE ) );

        //send 'AVAILABLE' until 'SLAVE_SETUP' received
        jack_info ( "Waiting for a master..." );
        do
        {
            //send 'available'
            session_params_t net_params;
            memset(&net_params, 0, sizeof ( session_params_t ));
            SessionParamsHToN(&fParams, &net_params);
            if ( fSocket.SendTo ( &net_params, sizeof ( session_params_t ), 0, fMulticastIP ) == SOCKET_ERROR )
                jack_error ( "Error in data send : %s", StrError ( NET_ERROR_CODE ) );
                
            //filter incoming packets : don't exit while no error is detected
            memset(&net_params, 0, sizeof ( session_params_t ));
            rx_bytes = fSocket.CatchHost ( &net_params, sizeof ( session_params_t ), 0 );
            SessionParamsNToH(&net_params, &host_params);
            if ( ( rx_bytes == SOCKET_ERROR ) && ( fSocket.GetError() != NET_NO_DATA ) )
            {
                jack_error ( "Can't receive : %s", StrError ( NET_ERROR_CODE ) );
                return NET_RECV_ERROR;
            }
        }
        while (strcmp(host_params.fPacketType, fParams.fPacketType)  && (GetPacketType(&host_params) != SLAVE_SETUP)  && (--try_count > 0));
        
        // Time out failure..
        if (try_count == 0) {
            jack_error("Time out error in connect");
            return NET_CONNECT_ERROR;
        }
   
        //everything is OK, copy parameters
        SessionParamsDisplay(&host_params);
        fParams = host_params;

        //connect the socket
        if (fSocket.Connect() == SOCKET_ERROR) {
            jack_error("Error in connect : %s", StrError(NET_ERROR_CODE));
            return NET_CONNECT_ERROR;
        }
        return NET_CONNECTED;
    }

    net_status_t JackNetSlaveInterface::SendStartToMaster()
    {
        jack_log("JackNetSlaveInterface::SendStartToMaster");

        //tell the master to start
        session_params_t net_params;
        memset(&net_params, 0, sizeof ( session_params_t ));
        SetPacketType ( &fParams, START_MASTER );
        SessionParamsHToN(&fParams, &net_params);
        if (fSocket.Send(&net_params, sizeof(session_params_t), 0) == SOCKET_ERROR)
        {
            jack_error("Error in send : %s", StrError(NET_ERROR_CODE));
            return (fSocket.GetError() == NET_CONN_ERROR) ? NET_ERROR : NET_SEND_ERROR;
        }
        return NET_ROLLING;
    }

    bool JackNetSlaveInterface::SetParams()
    {
        jack_log ( "JackNetSlaveInterface::SetParams" );

        JackNetInterface::SetParams();

        fTxHeader.fDataStream = 'r';
        fRxHeader.fDataStream = 's';

        //midi net buffers
        fNetMidiCaptureBuffer = new NetMidiBuffer ( &fParams, fParams.fSendMidiChannels, fRxData );
        fNetMidiPlaybackBuffer = new NetMidiBuffer ( &fParams, fParams.fReturnMidiChannels, fTxData );
        assert ( fNetMidiCaptureBuffer );
        assert ( fNetMidiPlaybackBuffer );

        //audio net buffers
        //fNetAudioCaptureBuffer = new NetFloatAudioBuffer ( &fParams, fParams.fSendAudioChannels, fRxData );
        //fNetAudioPlaybackBuffer = new NetFloatAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fTxData );
    
        try {
    #ifdef CELT
            if (fParams.fSendAudioChannels)
                fNetAudioCaptureBuffer = new NetCeltAudioBuffer ( &fParams, fParams.fSendAudioChannels, fRxData );
                
            if (fParams.fReturnAudioChannels)
                fNetAudioPlaybackBuffer = new NetCeltAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fTxData );
            
            // fNetAudioCaptureBuffer = new NetIntAudioBuffer ( &fParams, fParams.fSendAudioChannels, fRxData );
           // fNetAudioPlaybackBuffer = new NetIntAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fTxData );
    #else
            fNetAudioCaptureBuffer = new NetFloatAudioBuffer ( &fParams, fParams.fSendAudioChannels, fRxData );
            fNetAudioPlaybackBuffer = new NetFloatAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fTxData );
            
            //fNetAudioCaptureBuffer = new NetBufferedAudioBuffer ( &fParams, fParams.fSendAudioChannels, fRxData );
            //fNetAudioPlaybackBuffer = new NetBufferedAudioBuffer ( &fParams, fParams.fReturnAudioChannels, fTxData );
    #endif     
        } catch (exception&) {
            jack_error("NetAudioBuffer allocation error...");
            return false;
        }
    
        //set the new buffer sizes
        if ( SetNetBufferSize() == SOCKET_ERROR ) {
            jack_error ( "Can't set net buffer sizes : %s", StrError ( NET_ERROR_CODE ) );
            goto error;
        }
     
        return true;
        
    error:
        FreeNetworkBuffers();        
        return false;
    }

    int JackNetSlaveInterface::Recv(size_t size, int flags)
    {
        int rx_bytes = fSocket.Recv(fRxBuffer, size, flags);
        //handle errors
        if ( rx_bytes == SOCKET_ERROR )
        {
            net_error_t error = fSocket.GetError();
            //no data isn't really an error in realtime processing, so just return 0
            if ( error == NET_NO_DATA ) {
                jack_error ( "No data, is the master still running ?" );
            //if a network error occurs, this exception will restart the driver
            } else if ( error == NET_CONN_ERROR ) {
                jack_error ( "Connection lost." );
                throw JackNetException();
            } else {
                jack_error ( "Fatal error in slave receive : %s", StrError ( NET_ERROR_CODE ) );
            }
        }
        
        packet_header_t* header = reinterpret_cast<packet_header_t*>(fRxBuffer);
        PacketHeaderNToH(header, header);
        return rx_bytes;
    }

    int JackNetSlaveInterface::Send(size_t size, int flags)
    {
        packet_header_t* header = reinterpret_cast<packet_header_t*>(fTxBuffer);
        PacketHeaderHToN(header, header);
        int tx_bytes = fSocket.Send ( fTxBuffer, size, flags );
         
        //handle errors
        if ( tx_bytes == SOCKET_ERROR )
        {
            net_error_t error = fSocket.GetError();
            //if a network error occurs, this exception will restart the driver
            if ( error == NET_CONN_ERROR ) {
                jack_error ( "Connection lost." );
                throw JackNetException();
            } else {
                jack_error ( "Fatal error in slave send : %s", StrError ( NET_ERROR_CODE ) );
            }
        }
        return tx_bytes;
    }

    int JackNetSlaveInterface::SyncRecv()
    {
        int rx_bytes = 0;
        packet_header_t* rx_head = reinterpret_cast<packet_header_t*> ( fRxBuffer );
        
        //receive sync (launch the cycle)
        do
        {
            rx_bytes = Recv(HEADER_SIZE, 0);
            //connection issue, send will detect it, so don't skip the cycle (return 0)
            if ( rx_bytes == SOCKET_ERROR )
                return rx_bytes;
        }
        while ((strcmp(rx_head->fPacketType, "header") != 0) && (rx_head->fDataType != 's'));
        
        fRxHeader.fIsLastPckt = rx_head->fIsLastPckt;
        return rx_bytes;
    }

    int JackNetSlaveInterface::DataRecv()
    {
        int rx_bytes = 0;
        uint recvd_midi_pckt = 0;
        uint recvd_audio_pckt = 0;
      
        packet_header_t* rx_head = reinterpret_cast<packet_header_t*> ( fRxBuffer );

        while ( !fRxHeader.fIsLastPckt )
        {
            //how much data is queued on the rx buffer ?
            rx_bytes = Recv(HEADER_SIZE, MSG_PEEK);
            
            //error here, problem with recv, just skip the cycle (return -1)
            if ( rx_bytes == SOCKET_ERROR )
                return rx_bytes;
                
            if ( rx_bytes && ( rx_head->fDataStream == 's' ) && ( rx_head->fID == fParams.fID ) )
            {
                switch ( rx_head->fDataType )
                {
                    case 'm':   //midi
                        rx_bytes = Recv(rx_head->fPacketSize, 0);
                        fRxHeader.fCycle = rx_head->fCycle;
                        fRxHeader.fIsLastPckt = rx_head->fIsLastPckt;
                        fNetMidiCaptureBuffer->RenderFromNetwork(rx_head->fSubCycle, rx_bytes - HEADER_SIZE);
                        // Last midi packet is received, so finish rendering...
                        if (++recvd_midi_pckt == rx_head->fNumPacket)
                            fNetMidiCaptureBuffer->RenderToJackPorts();
                        break;

                    case 'a':   //audio
                        rx_bytes = Recv(rx_head->fPacketSize, 0);
                        fRxHeader.fCycle = rx_head->fCycle;
                        fRxHeader.fSubCycle = rx_head->fSubCycle;
                        fRxHeader.fIsLastPckt = rx_head->fIsLastPckt;
                        fNetAudioCaptureBuffer->RenderFromNetwork (rx_head->fCycle, rx_head->fSubCycle, rx_bytes - HEADER_SIZE);
                        // Last audio packet is received, so finish rendering...
                        if (fRxHeader.fIsLastPckt) 
                            fNetAudioCaptureBuffer->RenderToJackPorts();
                        break;

                    case 's':   //sync
                        jack_info ( "NetSlave : overloaded, skipping receive." );
                        // TODO : finish midi and audio rendering ?
                        fNetAudioCaptureBuffer->RenderToJackPorts();
                        return 0;
                }
            }
        }
        
        fRxHeader.fCycle = rx_head->fCycle;
        return 0;
    }

    int JackNetSlaveInterface::SyncSend()
    {
        //tx header
        if ( fParams.fSlaveSyncMode ) {
            fTxHeader.fCycle = fRxHeader.fCycle;
        } else {
            fTxHeader.fCycle++;
        }
        fTxHeader.fSubCycle = 0;
        fTxHeader.fDataType = 's';
        fTxHeader.fIsLastPckt = (fParams.fReturnMidiChannels == 0 && fParams.fReturnAudioChannels == 0) ?  1 : 0;
        fTxHeader.fPacketSize = HEADER_SIZE;
        
        memcpy(fTxBuffer, &fTxHeader, HEADER_SIZE);
        return Send (fTxHeader.fPacketSize, 0);
    }

    int JackNetSlaveInterface::DataSend()
    {
        uint subproc;
        uint data_size;

        //midi
        if (fParams.fReturnMidiChannels > 0)
        {
            //set global header fields and get the number of midi packets
            fTxHeader.fDataType = 'm';
            data_size = fNetMidiPlaybackBuffer->RenderFromJackPorts();
            fTxHeader.fNumPacket = fNetMidiPlaybackBuffer->GetNumPackets();
            for ( subproc = 0; subproc < fTxHeader.fNumPacket; subproc++ )
            {
                fTxHeader.fSubCycle = subproc;
                fTxHeader.fIsLastPckt = ((subproc == (fTxHeader.fNumPacket - 1)) && !fParams.fReturnAudioChannels) ? 1 : 0;
                fTxHeader.fPacketSize = HEADER_SIZE + fNetMidiPlaybackBuffer->RenderToNetwork(subproc, data_size);
                memcpy(fTxBuffer, &fTxHeader, HEADER_SIZE);
                if (Send(fTxHeader.fPacketSize, 0) == SOCKET_ERROR)
                    return SOCKET_ERROR;
            }
        }

        //audio
        if ( fParams.fReturnAudioChannels > 0)
        {
            fTxHeader.fDataType = 'a';
            data_size = fNetAudioPlaybackBuffer->RenderFromJackPorts();
            fTxHeader.fNumPacket = fNetAudioPlaybackBuffer->GetNumPackets();
            for ( subproc = 0; subproc < fTxHeader.fNumPacket; subproc++ )
            {
                fTxHeader.fSubCycle = subproc;
                fTxHeader.fIsLastPckt = (subproc == (fTxHeader.fNumPacket - 1)) ? 1 : 0;
                fTxHeader.fPacketSize = HEADER_SIZE + fNetAudioPlaybackBuffer->RenderToNetwork(subproc, data_size);
                memcpy(fTxBuffer, &fTxHeader, HEADER_SIZE);
                if (Send(fTxHeader.fPacketSize, 0) == SOCKET_ERROR)
                    return SOCKET_ERROR;
            }
        }
        return 0;
    }
    
    //network sync------------------------------------------------------------------------
    void JackNetSlaveInterface::EncodeSyncPacket()
    {
        //this method contains every step of sync packet informations coding
        //first of all, reset sync packet
        memset ( fTxData, 0, PACKET_AVAILABLE_SIZE );
        //then first step : transport
        if (fParams.fTransportSync) {
            EncodeTransportData();
            TransportDataHToN( &fReturnTransportData,  &fReturnTransportData);
            //copy to TxBuffer
            memcpy ( fTxData, &fReturnTransportData, sizeof ( net_transport_data_t ) );
        }
        //then others
        //...
    }
    
    void JackNetSlaveInterface::DecodeSyncPacket()
    {
        //this method contains every step of sync packet informations decoding process
        //first : transport
        if (fParams.fTransportSync) {
            //copy received transport data to transport data structure
            memcpy ( &fSendTransportData, fRxData, sizeof ( net_transport_data_t ) );
            TransportDataNToH( &fSendTransportData,  &fSendTransportData);
            DecodeTransportData();
        }
        //then others
        //...
    }

}