[OpenSIPS-Users] CANCEL handling

[Bogdan-Andrei Iancu]

Hi Mariana,

If CANCEL hits opensips while the the INVITE is still under processing 
(in a different process), the INVITE transaction will not exist yet (it 
is created by t_relay), so the t_check_trans() will return false -> 
script will exit without doing anything for the CANCEL - more or less 
the CANCEL will be dropped without being replied or fwded. This will 
force retransmission of Cancel -> buying more time to finish the 
processing of the INVITE.

Hope this helped.

Regards,

Bogdan-Andrei Iancu
OpenSIPS Founder and Developer
http://www.opensips-solutions.com


On 01/08/2013 10:49 PM, Mariana Arduini wrote:
> Hello all,
>
> I hope somebody can give me a kind hint on what to do here.
>
> We have this piece of code for CANCEL handling:
>
>     # CANCEL processing
>     if (is_method("CANCEL")) {
>         if (t_check_trans()) {
>             t_relay();
>         }
>         exit;
>     }
>
> What happens is sometimes we take too long to process the INVITE due 
> to some DB issues, and the UAC sends us a CANCEL before we relay the 
> INVITE.
>
> We don´t use t_newtran() because of this big warning in docs saying 
> that "the changes on the request that are made after this function 
> call will not be saved into transaction!!!". We need to perform a lot 
> of changes in the requests and I understand this wouldn´t be possible 
> after calling t_newtran().
>
> So our transaction is not created untill we relay the INVITE, which 
> means that any CANCEL received before that will be dropped.
>
> We also tried testing the CANCEL messages we´re receiving in these 
> cases with has_totag() and loose_route(), but they won´t pass as well.
>
> Is there any way to verify a CANCEL message in this scenario and relay 
> it in case is belongs to a valid transaction?
>
> Any help will be much appreciated.
>
> Regards,
> Mariana.
>
>
> _______________________________________________
> Users mailing list
> Users at lists.opensips.org
> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opensips.org/pipermail/users/attachments/20130109/4805e3ba/attachment.htm>