[OpenSER-Users] uac_replace_from and CANCEL

[Thomas Gelf]

FULL ACK :o)

I'm doing similar things here: uac_replace_from combined with uac_auth,
individual (not 1:1) credentials from db, AVPs etc etc... append_branch
is useless in your case, you're right (I need it for uac_auth).

It would REALLY be great if this job would be done automagically
*BIG HINT HINT* ;-p

Right now I'm struggling with all kinds of call forwarding. Conditional,
unconditional, REFER, 3xy etc - getting only SOME of the possible
scenarios working (also in combination with PSTN) is a big mess.

Christmas is still far, far away - otherwise I think I knew what to put
on my wishlist ;-)

Regards,
Thomas Gelf


Andreas Granig schrieb:
> Hi Thomas,
> 
> Yes, I'm doing it that way now (without that "append_branch()" though), 
> but if you have an uuid-based setup where you fetch the uuid from the 
> subscriber table during authentication of the INVITE and then with that 
> uuid fetch dynamic data from the usr_preferences table to be used for 
> "uac_rewrite_host()", then you have to do some work-arounds and hacks to 
> get that data for the CANCEL as well, which could be quite a pain.
> 
> So yes, it would be really great if this could be done automatically 
> *hint hint* :)
> 
> Andreas
> 
> Thomas Gelf wrote:
>> Applying uac_replace_from() to the CANCEL request should do the job,
>> it sadly doesn't happen automagically :'-(
>>
>> Try something like:
>>
>>      if(is_method("CANCEL") && uri =~ "^sip:...")
>>      {
>>          if(t_check_trans())
>>          {
>>              rewritehostport("...");
>>              uac_replace_from("...");
>>              append_branch();
>>          }
>>          if(!t_relay())
>>          {
>>              sl_reply_error();
>>          }
>>      }
>>
>> Cheers,
>> Thomas Gelf
>>
>> Andreas Granig schrieb:
>>> Hi,
>>>
>>> I hit another problem with a Cisco PGW in combination with CANCEL, and 
>>> I'm not sure which fault it is. If I do uac_replace_from in the INVITE, 
>>> the From-Header is altered somehow and sent to the PGW. So if A calls B 
>>> where B is a PGW, the From from A to OpenSER is for example 
>>> sip:a at somedomain and from OpenSER to B it's sip:other-a at somedomain.
>>>
>>> If the call is cancelled, the From-header isn't altered, so the From 
>>> from A to OpenSER is sip:a at somedomain and from OpenSER to B it's 
>>> sip:a at somedomain as well.
>>>
>>> Now the PGW seems to ignore this CANCEL, and I guess it's because of the 
>>> different From-usernames, since it works if I don't do any uac_replace_from.
>>>
>>> RFC3261 says in §9.1:
>>> The Request-URI, Call-ID, To, the numeric part of CSeq, and From header
>>> fields in the CANCEL request MUST be identical to those in the
>>> request being cancelled, including tags.
>>>
>>> So is it correct behavior of the PGW because the From header in the 
>>> CANCEL is different from the From header in the INVITE? Should OpenSER 
>>> alter the From in the CANCEL as well? Or should the PGW just check the 
>>>  From tags, but not the From URI?
>>>
>>> Andreas