[OpenSIPS-Users] CANCEL with a To tag.

[Iñaki Baz Castillo]

2009/5/11 Chris Maciejewski <chris at wima.co.uk>:
> You can see a SIP flow before I added "CANCEL" to a lose routing
> section of my Opensips config here:
>
> http://wima.co.uk/sip/2009-05-11_10-18-39-test-call_index.html
>
> Note: F23 is rejected by OpenSIPs as it got "tag" in a To: header.


As you can see, that CANCEL has "To tag" but no "Route" so it is
correctly rejected:

CANCEL sip:somePSTNno at sip.domain.com SIP/2.0
Content-Length: 0
Via: SIP/2.0/UDP {UA_SafeCom_IP}:5060;branch=z9hG4bK4d054e
To: <sip:somePSTNno at sip.domain.com>;tag=as7fa158c0
From: "John Smith" <sip:10002 at sip.domain.com>;tag=1294d4
Call-ID: 91b140a4-26ca446b-56590615-dc8b133c@{UA_SafeCom_IP}
CSeq: 1879 CANCEL
User-Agent: IP SIP Phone/2.0.6
Max-Forwards: 70
Contact: <sip:10002@{UA_SafeCom_IP}:5060>




> And after I added:
>
>  if (is_method("CANCEL"))
>  {
>    t_relay();
>    exit;
>  }
>
> to my lose routing logic, OpenSIPs generates CANCEL and sends it to
> the next hop:
>
> http://wima.co.uk/sip/2009-05-11_10-46-46-test-call_index.html

Yes, it's a correct workaround to allow CANCEL from that broken UA.
However, note that, even if CANCEL F23 has "To tag", the CANCEL
generated by OpenSIPS doesn't it (F25).


-- 
Iñaki Baz Castillo
<ibc at aliax.net>