xlxd/src/cdextraprotocol.cpp

//
//  cdextraprotocol.cpp
//  xlxd
//
//  Created by Jean-Luc Deltombe (LX3JL) on 01/11/2015.
//  Copyright © 2015 Jean-Luc Deltombe (LX3JL). All rights reserved.
//
// ----------------------------------------------------------------------------
//    This file is part of xlxd.
//
//    xlxd 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 3 of the License, or
//    (at your option) any later version.
//
//    xlxd 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 Foobar.  If not, see <http://www.gnu.org/licenses/>. 
// ----------------------------------------------------------------------------

#include "main.h"
#include <string.h>
#include "cdextraclient.h"
#include "cdextraprotocol.h"
#include "creflector.h"
#include "cgatekeeper.h"


////////////////////////////////////////////////////////////////////////////////////////
// operation

bool CDextraProtocol::Init(void)
{
    bool ok;
    
    // base class
    ok = CProtocol::Init();
    
    // update the reflector callsign
    m_ReflectorCallsign.PatchCallsign(0, (const uint8 *)"XRF", 3);
    
    // create our socket
    ok &= m_Socket.Open(DEXTRA_PORT);
    if ( !ok )
    {
        std::cout << "Error opening socket on port UDP" << DEXTRA_PORT << " on ip " << g_Reflector.GetListenIp() << std::endl;
    }
    
    // update time
    m_LastKeepaliveTime.Now();
    
    // done
    return ok;
}

////////////////////////////////////////////////////////////////////////////////////////
// task

void CDextraProtocol::Task(void)
{
    CBuffer             Buffer;
    CIp                 Ip;
    CCallsign           Callsign;
    char                ToLinkModule;
    int                 ProtRev;
    CDvHeaderPacket     *Header;
    CDvFramePacket      *Frame;
    CDvLastFramePacket  *LastFrame;
    
    // any incoming packet ?
    if ( m_Socket.Receive(&Buffer, &Ip, 20) != -1 )
    {
        // crack the packet
        if ( (Frame = IsValidDvFramePacket(Buffer)) != NULL )
        {
            //std::cout << "DExtra DV frame"  << std::endl;
            
            // handle it
            OnDvFramePacketIn(Frame, &Ip);
        }
        else if ( (Header = IsValidDvHeaderPacket(Buffer)) != NULL )
        {
            //std::cout << "DExtra DV header:"  << std::endl << *Header << std::endl;
            //std::cout << "DExtra DV header:"  << std::endl;
            
            // callsign muted?
            if ( g_GateKeeper.MayTransmit(Header->GetMyCallsign(), Ip, PROTOCOL_DEXTRA, Header->GetRpt2Module()) )
            {
                // handle it
                OnDvHeaderPacketIn(Header, Ip);
            }
            else
            {
                delete Header;
            }
        }
        else if ( (LastFrame = IsValidDvLastFramePacket(Buffer)) != NULL )
        {
            //std::cout << "DExtra DV last frame" << std::endl;
            
            // handle it
            OnDvLastFramePacketIn(LastFrame, &Ip);
        }
        else if ( IsValidConnectPacket(Buffer, &Callsign, &ToLinkModule, &ProtRev) )
        {
            std::cout << "DExtra connect packet for module " << ToLinkModule << " from " << Callsign << " at " << Ip << " rev " << ProtRev << std::endl;
            
            // callsign authorized?
            if ( g_GateKeeper.MayLink(Callsign, Ip, PROTOCOL_DEXTRA) )
            {
                // valid module ?
                if ( g_Reflector.IsValidModule(ToLinkModule) )
                {
                    // acknowledge the request
                    EncodeConnectAckPacket(&Buffer, ProtRev);
                    m_Socket.Send(Buffer, Ip);

                    // check if any client currently streaming on the module
                    CClients *clients = g_Reflector.GetClients();
                    for ( int i = 0; i < clients->GetSize(); i++ )
                    {
                        if ( clients->GetClient(i)->IsAMaster() && (clients->GetClient(i)->GetReflectorModule() == ToLinkModule) )
                        {
                            // found a client streaming on the module, encode a copy of the cached header packet
                            CBuffer buffer2;
                            if ( EncodeDvPacket(m_StreamsCache[g_Reflector.GetModuleIndex(ToLinkModule)].m_dvHeader, &buffer2) )
                            {
                                // and send it to the connecting client, so it can listen the already streaming client
                                for ( int j = 0; j < 5; j++ )
                                {
                                    m_Socket.Send(buffer2, Ip);
                                }
                            }
                            break; // done, stop here
                        }
                    }
                    g_Reflector.ReleaseClients();
                    
                    // create the client
                    CDextraClient *client = new CDextraClient(Callsign, Ip, ToLinkModule, ProtRev);
                    
                    // and append
                    g_Reflector.GetClients()->AddClient(client);
                    g_Reflector.ReleaseClients();
                }
                else
                {
                    std::cout << "DExtra node " << Callsign << " connect attempt on non-existing module" << std::endl;
                    
                    // deny the request
                    EncodeConnectNackPacket(&Buffer);
                    m_Socket.Send(Buffer, Ip);
                }
            }
            else
            {
                // deny the request
                EncodeConnectNackPacket(&Buffer);
                m_Socket.Send(Buffer, Ip);
            }
        }
        else if ( IsValidDisconnectPacket(Buffer, &Callsign) )
        {
            std::cout << "DExtra disconnect packet from " << Callsign << " at " << Ip << std::endl;
            
            // find client & remove it
            CClients *clients = g_Reflector.GetClients();
            CClient *client = clients->FindClient(Ip, PROTOCOL_DEXTRA);
            if ( client != NULL )
            {
                // ack disconnect packet
                if ( client->GetProtocolRevision() == 1 )
                {
                    EncodeDisconnectedPacket(&Buffer);
                    m_Socket.Send(Buffer, Ip);
                }
                else if ( client->GetProtocolRevision() == 2 )
                {
                    m_Socket.Send(Buffer, Ip);
                }
               // and remove it
                clients->RemoveClient(client);
            }
            g_Reflector.ReleaseClients();
        }
        else if ( IsValidKeepAlivePacket(Buffer, &Callsign) )
        {
            //std::cout << "DExtra keepalive packet from " << Callsign << " at " << Ip << std::endl;
            
            // find all clients with that callsign & ip and keep them alive
            CClients *clients = g_Reflector.GetClients();
            int index = -1;
            CClient *client = NULL;
            while ( (client = clients->FindNextClient(Callsign, Ip, PROTOCOL_DEXTRA, &index)) != NULL )
            {
               client->Alive();
            }
            g_Reflector.ReleaseClients();
        }
        else
        {
            std::cout << "DExtra packet (" << Buffer.size() << ")" << std::endl;
            //std::cout << Buffer.data() << std::endl;
        }
    }
    
    // handle end of streaming timeout
    CheckStreamsTimeout();
        
    // handle queue from reflector
    HandleQueue();
        
    // keep client alive
    if ( m_LastKeepaliveTime.DurationSinceNow() > DEXTRA_KEEPALIVE_PERIOD )
    {
        //
        HandleKeepalives();
        
        // update time
        m_LastKeepaliveTime.Now();
    }
}

////////////////////////////////////////////////////////////////////////////////////////
// queue helper

void CDextraProtocol::HandleQueue(void)
{
    m_Queue.Lock();
    while ( !m_Queue.empty() )
    {
        // get the packet
        CPacket *packet = m_Queue.front();
        m_Queue.pop();
        
        // get our sender's id
        int iModId = g_Reflector.GetModuleIndex(packet->GetModuleId());
        
        // check if it's header and update cache
        if ( packet->IsDvHeader() )
        {
            // this relies on queue feeder setting valid module id
            m_StreamsCache[iModId].m_dvHeader = CDvHeaderPacket((const CDvHeaderPacket &)*packet);
        }

        // encode it
        CBuffer buffer;
        if ( EncodeDvPacket(*packet, &buffer) )
        {
            // and push it to all our clients linked to the module and who are not streaming in
            CClients *clients = g_Reflector.GetClients();
            int index = -1;
            CClient *client = NULL;
            while ( (client = clients->FindNextClient(PROTOCOL_DEXTRA, &index)) != NULL )
            {
                // is this client busy ?
                if ( !client->IsAMaster() && (client->GetReflectorModule() == packet->GetModuleId()) )
                {
                    // no, send the packet
                    int n = packet->IsDvHeader() ? 5 : 1;
                    for ( int i = 0; i < n; i++ )
                    {
                        m_Socket.Send(buffer, client->GetIp());
                    }
                }
            }
            g_Reflector.ReleaseClients();
        }
        
        
        // done
        delete packet;
    }
    m_Queue.Unlock();
}

////////////////////////////////////////////////////////////////////////////////////////
// keepalive helpers

void CDextraProtocol::HandleKeepalives(void)
{
    // DExtra protocol sends and monitors keepalives packets
    // event if the client is currently streaming
    // so, send keepalives to all
    CBuffer keepalive;
    EncodeKeepAlivePacket(&keepalive);
    
    // iterate on clients
    CClients *clients = g_Reflector.GetClients();
    int index = -1;
    CClient *client = NULL;
    while ( (client = clients->FindNextClient(PROTOCOL_DEXTRA, &index)) != NULL )
    {
        // send keepalive
        m_Socket.Send(keepalive, client->GetIp());
        
        // client busy ?
        if ( client->IsAMaster() )
        {
            // yes, just tickle it
            client->Alive();
        }
        // otherwise check if still with us
        else if ( !client->IsAlive() )
        {
            // no, disconnect
            CBuffer disconnect;
            EncodeDisconnectPacket(&disconnect);
            m_Socket.Send(disconnect, client->GetIp());
            
            // remove it
            std::cout << "DExtra client " << client->GetCallsign() << " keepalive timeout" << std::endl;
            clients->RemoveClient(client);
        }
        
    }
    g_Reflector.ReleaseClients();
}

////////////////////////////////////////////////////////////////////////////////////////
// streams helpers

bool CDextraProtocol::OnDvHeaderPacketIn(CDvHeaderPacket *Header, const CIp &Ip)
{
    bool newstream = false;
    
    // find the stream
    CPacketStream *stream = GetStream(Header->GetStreamId());
    if ( stream == NULL )
    {
        // no stream open yet, open a new one
        CCallsign via(Header->GetRpt1Callsign());
        
        // find this client
        CClient *client = g_Reflector.GetClients()->FindClient(Ip, PROTOCOL_DEXTRA);
        if ( client != NULL )
        {
            // get client callsign
            via = client->GetCallsign();
            // apply protocol revision details
            if ( client->GetProtocolRevision() == 2 )
            {
                // update Header RPT2 module letter with
                // the module the client is linked to
                Header->SetRpt2Module(client->GetReflectorModule());
            }
            // and try to open the stream
            if ( (stream = g_Reflector.OpenStream(Header, client)) != NULL )
            {
                // keep the handle
                m_Streams.push_back(stream);
                newstream = true;
            }
        }
        // release
        g_Reflector.ReleaseClients();
        
        // update last heard
        g_Reflector.GetUsers()->Hearing(Header->GetMyCallsign(), via, Header->GetRpt2Callsign());
        g_Reflector.ReleaseUsers();
        
        // delete header if needed
        if ( !newstream )
        {
            delete Header;
        }
    }
    else
    {
        // stream already open
        // skip packet, but tickle the stream
        stream->Tickle();
        // and delete packet
        delete Header;
    }
    
    // done
    return newstream;
}

////////////////////////////////////////////////////////////////////////////////////////
// packet decoding helpers

bool CDextraProtocol::IsValidConnectPacket(const CBuffer &Buffer, CCallsign *callsign, char *reflectormodule, int *revision)
{
    bool valid = false;
    if ((Buffer.size() == 11) && (Buffer.data()[9] != ' '))
    {
        callsign->SetCallsign(Buffer.data(), 8);
        callsign->SetModule(Buffer.data()[8]);
        *reflectormodule = Buffer.data()[9];
        *revision = (Buffer.data()[10] == 11) ? 1 : 0;
        valid = (callsign->IsValid() && IsLetter(*reflectormodule));
        // detect revision
        if ( (Buffer.data()[10] == 11) )
        {
            *revision = 1;
        }
        else if ( callsign->HasSameCallsignWithWildcard(CCallsign("XRF*")) )
        {
            *revision = 2;
        }
        else
        {
            *revision = 0;
        }
    }
    return valid;
}

bool CDextraProtocol::IsValidDisconnectPacket(const CBuffer &Buffer, CCallsign *callsign)
{
    bool valid = false;
    if ((Buffer.size() == 11) && (Buffer.data()[9] == ' '))
    {
        callsign->SetCallsign(Buffer.data(), 8);
        callsign->SetModule(Buffer.data()[8]);
       valid = callsign->IsValid();
    }
    return valid;
}

bool CDextraProtocol::IsValidKeepAlivePacket(const CBuffer &Buffer, CCallsign *callsign)
{
    bool valid = false;
    if (Buffer.size() == 9)
    {
        callsign->SetCallsign(Buffer.data(), 8);
        valid = callsign->IsValid();
    }
    return valid;
}

CDvHeaderPacket *CDextraProtocol::IsValidDvHeaderPacket(const CBuffer &Buffer)
{
    CDvHeaderPacket *header = NULL;
    
    if ( (Buffer.size() == 56) && (Buffer.Compare((uint8 *)"DSVT", 4) == 0) &&
         (Buffer.data()[4] == 0x10) && (Buffer.data()[8] == 0x20) )
    {
        // create packet
        header = new CDvHeaderPacket((struct dstar_header *)&(Buffer.data()[15]),
                                *((uint16 *)&(Buffer.data()[12])), 0x80);
        // check validity of packet
        if ( !header->IsValid() )
        {
            delete header;
            header = NULL;
        }
    }
    return header;
}

CDvFramePacket *CDextraProtocol::IsValidDvFramePacket(const CBuffer &Buffer)
{
    CDvFramePacket *dvframe = NULL;
    
    if ( (Buffer.size() == 27) && (Buffer.Compare((uint8 *)"DSVT", 4) == 0) &&
         (Buffer.data()[4] == 0x20) && (Buffer.data()[8] == 0x20) &&
         ((Buffer.data()[14] & 0x40) == 0) )
    {
        // create packet
        dvframe = new CDvFramePacket((struct dstar_dvframe *)&(Buffer.data()[15]),
                                     *((uint16 *)&(Buffer.data()[12])), Buffer.data()[14]);
        // check validity of packet
        if ( !dvframe->IsValid() )
        {
            delete dvframe;
            dvframe = NULL;
        }
    }
    return dvframe;
}

CDvLastFramePacket *CDextraProtocol::IsValidDvLastFramePacket(const CBuffer &Buffer)
{
    CDvLastFramePacket *dvframe = NULL;
    
    if ( (Buffer.size() == 27) && (Buffer.Compare((uint8 *)"DSVT", 4) == 0) &&
         (Buffer.data()[4] == 0x20) && (Buffer.data()[8] == 0x20) &&
         ((Buffer.data()[14] & 0x40) != 0) )
    {
        // create packet
        dvframe = new CDvLastFramePacket((struct dstar_dvframe *)&(Buffer.data()[15]),
                                         *((uint16 *)&(Buffer.data()[12])), Buffer.data()[14]);
        // check validity of packet
        if ( !dvframe->IsValid() )
        {
            delete dvframe;
            dvframe = NULL;
        }
    }
    return dvframe;
}

////////////////////////////////////////////////////////////////////////////////////////
// packet encoding helpers

void CDextraProtocol::EncodeKeepAlivePacket(CBuffer *Buffer)
{
   Buffer->Set(GetReflectorCallsign());
}

void CDextraProtocol::EncodeConnectAckPacket(CBuffer *Buffer, int ProtRev)
{
   // is it for a XRF or repeater
    if ( ProtRev == 2 )
    {
        // XRFxxx
        uint8 rm = (Buffer->data())[8];
        uint8 lm = (Buffer->data())[9];
        Buffer->clear();
        Buffer->Set((uint8 *)(const char *)GetReflectorCallsign(), CALLSIGN_LEN);
        Buffer->Append(lm);
        Buffer->Append(rm);
        Buffer->Append((uint8)0);
    }
    else
    {
        // regular repeater
        uint8 tag[] = { 'A','C','K',0 };
        Buffer->resize(Buffer->size()-1);
        Buffer->Append(tag, sizeof(tag));
    }
}

void CDextraProtocol::EncodeConnectNackPacket(CBuffer *Buffer)
{
    uint8 tag[] = { 'N','A','K',0 };
    Buffer->resize(Buffer->size()-1);
    Buffer->Append(tag, sizeof(tag));
}

void CDextraProtocol::EncodeDisconnectPacket(CBuffer *Buffer)
{
    uint8 tag[] = { ' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',0 };
    Buffer->Set(tag, sizeof(tag));
}

void CDextraProtocol::EncodeDisconnectedPacket(CBuffer *Buffer)
{
    uint8 tag[] = { 'D','I','S','C','O','N','N','E','C','T','E','D' };
    Buffer->Set(tag, sizeof(tag));
}

bool CDextraProtocol::EncodeDvHeaderPacket(const CDvHeaderPacket &Packet, CBuffer *Buffer) const
{
    uint8 tag[]	= { 'D','S','V','T',0x10,0x00,0x00,0x00,0x20,0x00,0x01,0x02 };
    struct dstar_header DstarHeader;
    
    Packet.ConvertToDstarStruct(&DstarHeader);
    
    Buffer->Set(tag, sizeof(tag));
    Buffer->Append(Packet.GetStreamId());
    Buffer->Append((uint8)0x80);
    Buffer->Append((uint8 *)&DstarHeader, sizeof(struct dstar_header));
    
    return true;
}

bool CDextraProtocol::EncodeDvFramePacket(const CDvFramePacket &Packet, CBuffer *Buffer) const
{
    uint8 tag[] = { 'D','S','V','T',0x20,0x00,0x00,0x00,0x20,0x00,0x01,0x02 };
    
    Buffer->Set(tag, sizeof(tag));
    Buffer->Append(Packet.GetStreamId());
    Buffer->Append((uint8)(Packet.GetPacketId() % 21));
    Buffer->Append((uint8 *)Packet.GetAmbe(), AMBE_SIZE);
    Buffer->Append((uint8 *)Packet.GetDvData(), DVDATA_SIZE);
    
    return true;
    
}

bool CDextraProtocol::EncodeDvLastFramePacket(const CDvLastFramePacket &Packet, CBuffer *Buffer) const
{
    uint8 tag1[] = { 'D','S','V','T',0x20,0x00,0x00,0x00,0x20,0x00,0x01,0x02 };
    uint8 tag2[] = { 0x55,0xC8,0x7A,0x00,0x00,0x00,0x00,0x00,0x00,0x25,0x1A,0xC6 };
    
    Buffer->Set(tag1, sizeof(tag1));
    Buffer->Append(Packet.GetStreamId());
    Buffer->Append((uint8)((Packet.GetPacketId() % 21) | 0x40));
    Buffer->Append(tag2, sizeof(tag2));
    
    return true;
}