[OpenSIPS-Users] Need ideas to tamper with CSeq

[Ovidiu Sas]

On Thu, Mar 31, 2011 at 10:37 AM, Cindy Leung <cinthia721 at gmail.com> wrote:
> I guess I wasn't being clear enough in the call flow.  I assume the CSeq in the CANCEL has to be the same as the second INVITE.
>
> 1. Phone sends out INVITE #1, OpenSIPS responds with 401, Phone ACK'd.  I believe the transaction is over at this point.
> 2. Phone sends out INVITE #2 with auth, OpenSIPS accepts the INVITE and send back 180.  Phone now sends out a CANCEL, but the CSeq is not the same as INVITE #2.
>
> As far as I can tell, everything else (ruri, call-id...) is the same except for CSeq.

Exactly!  You broke the CSeq between caller and callee.  A proxy
should never do that!
Even if you fix somehow your CANCEL issue, calls will never complete.
The 200ok will have a different CSeq then the initial INVITE (for the
caller) and it will be discarded (by the caller).
Also, BYE will not work.
You have bigger issues here then just a CANCEL.


Regards,
Ovidiu Sas