C++ DialogTracker::ProcessMediaOffer方法代码示例

void WaitingForMediaOffer::ProvisionalResponse( DialogTracker& impl, SipMessage& response, const char* address, int port ) const
{
   if( response.getResponseStatusCode() != SIP_TRYING_CODE )
   {
      // Both reliable and unreliable provisional responses can carry SDP bodies.  According to 
      // draft-ietf-sipping-sip-offeranswer-04.txt section 3.1, unreliable provisional responses
      // carrying an answer is a mere previes of what the 'real' SDP answer will be and that it
      // must be identical to it.  Since we may be changing the SDP of the 'real' answer to compensate
      // for NATs we need to also manipulate the 'preview' answer to make match the requirement that
      // the preview and 'real' answers be identical.
      impl.ProcessMediaOffer( response, INITIAL_OFFER_ANSWER );

      // we are receiving a provisional response - check if it is sent reliably...
      if( response.getHeaderValue( 0, SIP_RSEQ_FIELD ) )
      {
         // Presence of RSeq: header in the message indicates that it is sent reliably
         ChangeState( impl, impl.pWaitingForPrackWithMediaAnswer );
      }
      else
      {
         // We have received an unreliable provisional response - although that does
         // not cause a state machine state change, we need to reset the tick counter
         // to show that there is still activity in this dialog.
         impl.resetTimerTickCounter();            
      }
   }
}

void WaitingForMediaOffer::ProvisionalResponse( DialogTracker& impl, SipMessage& response, const char* address, int port ) const
{
   if( response.getResponseStatusCode() != SIP_TRYING_CODE )
   {
      // Both reliable and unreliable provisional responses can carry SDP bodies.  According to
      // draft-ietf-sipping-sip-offeranswer-04.txt section 3.1, unreliable provisional responses
      // carrying an offer is a mere preview of what the 'real' SDP offfer will be and that it
      // must be identical to it.  Since we may be changing the SDP of the 'real' offer to compensate
      // for NATs we need to also manipulate the 'preview' offer to make it meet the requirement that
      // the preview and 'real' offers be identical.
      impl.ProcessMediaOffer( response, INITIAL_OFFER_ANSWER );

      // we are receiving a provisional response - check if it is sent reliably...
      if( response.getHeaderValue( 0, SIP_RSEQ_FIELD ) )
      {
         // Presence of RSeq: header in the message indicates that it is sent reliably
         ChangeState( impl, impl.pWaitingForPrackWithMediaAnswer );
      }
      else
      {
         // We have received an unreliable provisional response - take a copy of the
         // patched SDP so that it can be re-applied to subsequent responses carrying
         // the same SDP body.
         impl.savePatchedSdpPreview( response );
         ChangeState( impl, impl.pWaitingFor200OkWithMediaOffer );
      }
   }
}

bool WaitingForPrack::PrackRequest( DialogTracker& impl, SipMessage& request, TransactionDirectionality direction, const char* address, int port ) const
{
   if( request.hasSdpBody() )
   {
      impl.ProcessMediaOffer( request, NON_INITIAL_OFFER_ANSWER );
      ChangeState( impl, impl.pWaitingFor200OkWithAnswerForPrack );
   }
   else
   {
      ChangeState( impl, impl.pWaitingFor200OkForPrack );
   }
   return true;
}

bool WaitingForInvite::InviteRequest( DialogTracker& impl, SipMessage& request, TransactionDirectionality direction, const char* address, int port ) const
{
   bool bTrackRequestResponse = false;
   impl.setTransactionDirectionality( direction );

   // check is another sipX is already taking care of NAT traversing this session. 
   if( !impl.isRequestAlreadyHandledByOther( request ) )
   {
      bTrackRequestResponse = true;
      impl.markRequestAsHandledByUs( request );
      // check if the INVITE contains an SDP offer
      if( request.hasSdpBody() )
      {
         // request contains an SDP offer.  Check if the SDP or the or the actual
         // location of the two endpoints impose the use of a media relay. 
         if( impl.doesEndpointsLocationImposeMediaRelay() )
         {
            OsSysLog::add(FAC_NAT,PRI_DEBUG,"'%s:%s' - Media relay required",
                  impl.name(), impl.GetCurrentState()->name() );   
            impl.setMediaRelayRequiredFlag();
         }
         else
         {
            OsSysLog::add(FAC_NAT,PRI_DEBUG,"'%s:%s' - Media relay not required",
                  impl.name(), impl.GetCurrentState()->name() );    
            impl.clearMediaRelayRequiredFlag();
         }
         impl.ProcessMediaOffer( request, INITIAL_OFFER_ANSWER );         
         ChangeState( impl, impl.pWaitingForMediaAnswer );
      }
      else
      {
         // request does contains an SDP offer.  This INVITE may be used to set up a 3PCC
         // call.  Play it safe and impose the use of a media relay to guarantee speechpath
         impl.setMediaRelayRequiredFlag();
         ChangeState( impl, impl.pWaitingForMediaOffer );
      }
   }
   else
   {
      // this particular session is already being handled by another sipX i nthe network.
      // That sipX is taking care of overcoming the NATs that separate the endpoints involved
      // in that session.  There isn't much value we can add here so just bail on tracking that
      // session.
      ChangeState( impl, impl.pMoribund );
   }
   return bTrackRequestResponse;
}

void WaitingForMediaOffer::SuccessfulResponse( DialogTracker& impl, SipMessage& response, const char* address, int port ) const
{
   impl.ProcessMediaOffer( response, INITIAL_OFFER_ANSWER );
   ChangeState( impl, impl.pWaitingForAckWithAnswerForInvite );
}