[Live-devel] client port validation

[Eric Pronovost]

An RTSP client application that connects to my RTSP server is launched in
multi instances. However, it always start with client_port 9000.

SETUP rtsp://192.168.0.60:9395/live005/sub.sdp/track1 RTSP/1.0
CSeq: 2
Transport: RTP/AVP;unicast;client_port=9000-9001
etc...

When the first instance is launched, it works with port 9000. The second
instance is then launched and tries port 9000 again. It doesn't work, so a
TEARDOWN is performed. The problem is that the teardown of the second
instance is stopping the video of the first instance.

By debugging, I discovered that, inside StreamState::endPlaying(), the
following call:
if (fRTPgs != NULL) fRTPgs->removeDestination(dests->addr, dests->rtpPort);
if (fRTCPgs != NULL) fRTCPgs->removeDestination(dests->addr,
dests->rtcpPort);
will stop the video from the first instance, since the ports are the same.


I coded the following workaround:

In ::handleCmd_SETUP(), before the call
to subsession->getStreamParameters(), I added a custom function that checks
if the address/ports are already in use:

bool bAlreadyInUse =
subsession->destinationsAlreadyInUse(ourClientConnection->fClientAddr.sin_addr.s_addr,
clientRTPPort, clientRTCPPort, tcpSocketNum, rtpChannelId, rtcpChannelId,
destinationAddress);
    if (bAlreadyInUse)
       break;


Here's the code to my custom function:

bool OnDemandServerMediaSubsession::destinationsAlreadyInUse(netAddressBits
clientAddress, Port const& clientRTPPort,
   Port const& clientRTCPPort,
   int tcpSocketNum,
   unsigned char rtpChannelId,
   unsigned char rtcpChannelId,
   netAddressBits& destinationAddress)
{
   if (tcpSocketNum >= 0)  // TCP
      return false;

   if (destinationAddress == 0) destinationAddress = clientAddress;
   struct in_addr destinationAddr; destinationAddr.s_addr =
destinationAddress;

   Destinations* destinations;
   if (tcpSocketNum < 0) { // UDP
      destinations = new Destinations(destinationAddr, clientRTPPort,
clientRTCPPort);
   }
   else { // TCP
      destinations = new Destinations(tcpSocketNum, rtpChannelId,
rtcpChannelId);
   }

   HashTable::Iterator* iter =
HashTable::Iterator::create(*fDestinationsHashTable);
   Destinations* dests;
   char const* key; // dummy
   bool bAlreadyExist = false;
   while ((dests = (Destinations*)(iter->next(key))) != NULL)
   {
      if (dests->addr.S_un.S_addr == destinations->addr.S_un.S_addr)
      {
         if ((dests->rtcpPort.num() == destinations->rtcpPort.num()) ||
(dests->rtpPort.num() == destinations->rtpPort.num()))
            bAlreadyExist = true;
      }
   }
   delete iter;
   return bAlreadyExist;
}


With this workaround, the second instance won't stop the video of the first
instance, and it will receive RTSP/1.0 454 Session Not Found.

I consider this as a patch, not sure what the best solution should be...
any suggestions?
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