[OpenSIPS-Users] mediaproxy bug with offer answer in different transaction

[Eric Tamme]

Hi Saúl, and others,

We have discovered a bug in mediaproxy where it does not recognize an 
answer that is part of a different transaction, this is caused by how 
mediaproxy tracks offer/answer based on cseq.  Here is the example offer 
answer scenario from RFC3262 that does not work.

UAC  INVITE Cseq: 1 (no SDP offer) ->

<- 183 with SDP offer

PRACK CSeq: 2, Rseq: 1  with SDP answer->

Because the PRACK is a different transaction, and has a different CSeq 
than the offer, mediaproxy assumes it is a new offer, rather than an answer.

Can you offer any thoughts on what might be the best way to fix this 
issue?  We are happy to work on a patch as well - but would like to have 
input from the maintainers so that we can be sure it would be accepted 
upstream.

Thanks,

-Eric