RTP/AVP vs RTP/SAVP negotiation

[bennylp]

Issues:

1. Currently, when pjsip sends offer with RTP/AVP with a=crypto attribute (SRTP mode optional), and when remote answers with RTP/SAVP, SDP negotiation will fail and media will not be created, but the call is not terminated.
2. When pjsip sends offer with RTP/SAVP (SRTP mode mandatory), and remote answers with RTP/AVP, SDP negotiation will fail and media will not be created, but the call is not terminated.

[nanang]

Attachment ticket467.patch:

• bug fixed in transport_srtp.c: in optional mode, it doesn't need to check media transport type
• changed sdp_neg.c and session.c : disable offer-answer transport comparison when SRTP enabled, the transport SRTP will do the validation

[nanang]

Attachment ticket467.2.patch:

• transport:
  • introduced new option for media/SDP handling in transport
  • added option param on media_create (affecting transport interface & all transport implementations, and transport user)

• transport_srtp.c:
  • bug fix: in optional mode, it doesn't need to check media transport type

• sdp_neg.c & session.c:
  • perform less strict media transport comparison (from strict pj_stricmp to pjmedia_sdp_transport_cmp)

• pjmedia_call.c:
  • uncomment disconnect_call if status!=PJ_SUCCES on update media

[bennylp]

Committed ticket467.2.patch in r1810 with minor modifications:

• changed type of option parameter in media_create() from pjmedia_tranport_media_option to unsigned int, to allow bit mask combinations in the future.
• Added doxygen documentation for the new option parameter.

Thanks.

[bennylp]

New issues reported by Klaus Darilion:

The BYE is sent before the ACK (from INV-200). I think this is valid but IMO it would be nicer if BYE is sent after ACK.

Unfortunately this is not easy to fix as the "bad" SDP is detected (and BYE is sent) upon receipt of 200/OK. Also sending ACK first will cause the call to go to CONFIRMED state, which may not be desired.

The BYE contains a session description

Yes this is a but. Ticket is reopened.

Thanks for the report.

[nanang]

Fixed call_disconnect() in pjsua_call.c, put SDP only if message type is response.

[bennylp]

Patch ticket467.3.patch committed (don't send SDP with BYE)