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 );
}