[OpenSIPS-Users] CANCEL with a To tag.

[Chris Maciejewski]

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.

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


2009/5/11 Iñaki Baz Castillo <ibc at aliax.net>:
> 2009/5/11 Chris Maciejewski <chris at wima.co.uk>:
>> Hi,
>>
>> I would like to ask what would be the best way to handle CANCEL
>> request with a To tag. I know such a CANCEL request is not RFC
>> compatible
>
> CANCEL is hop-by-hop. This means that when OpenSIPS receives a CANCEL,
> it *doesn't* route it, but it generates a new one (this occurs when
> you do "t_relay()" for a CANCEL).
> It's impossible to add "To tag" to a CANCEL generated by OpenSIPS
> (expect if the CANCEL occurs for a re-INVITE being into an already
> established dialog, so arriving CANCEL has To tag and OpenSIPS routes
> it as any other in-dialog request).
>
>
>>  but unfortunately I came across some buggy UAs doing this.
>
> What do you mean with it? what does this UAS?
>
>
> --
> Iñaki Baz Castillo
> <ibc at aliax.net>
>
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