[OpenSER-Users] uac_replace_from and CANCEL

[Andreas Granig]

Hi Bogdan,

Not 100% sure since I haven't tested with 1.2.2 and uac_replace_from() 
NOT being called indirectly from branch_route.

What I can tell though is that with 1.3.1 and calling uac_replace_from 
from request_route, it works as expected.

Thanks for clarification,
Andreas

Bogdan-Andrei Iancu wrote:
> Hi Andreas,
> 
> I guess this is also related to the improper usage of uac_replace_from() 
> from branch route, right?
> 
> Regards,
> Bogdan
> 
> 
> Andreas Granig wrote:
>> Hi again,
>>
>> This problem actually applies to the ACK for the 487 if the CANCEL as 
>> well, and there it's even worse.
>>
>> RFC3261 says in 17.1.1.3:
>> The ACK request constructed by the client transaction MUST contain
>> values for the Call-ID, From, and Request-URI that are equal to the
>> values of those header fields in the request passed to the transport
>> by the client transaction
>>
>> On the other hand, in 17.2.3 it says regarding server transaction 
>> matching:
>> The ACK request matches a transaction if the Request-
>> URI, From tag, Call-ID, CSeq number (not the method), and top Via
>> header field match those of the INVITE request which created the
>> transaction, and the To tag of the ACK matches the To tag of the
>> response sent by the server transaction.
>>
>> Now if for some reason, the UAC in this case is OpenSER and the UAS is 
>> a server which not only compares the From tag, but the overall 
>> From-Header (like the Cisco PGW in version 9.6 seems to do), then both 
>> of the parties don't behave correctly, and it's a little bit hard to 
>> argue with vendors who has to move now.
>>
>> The real problem I have now is that for the CANCEL I can at least 
>> manually replace From, but for ACK, OpenSER refuses to do so. In 
>> "auto" mode, uac_replace_from bails out with "ERROR:uac:replace_from: 
>> decline FROM replacing in sequential request in auto mode (has TO 
>> tag)". In "manual" mode, it doesn't complain, but the From still isn't 
>> replaced, and also an ugly hack like "remove_hf("From"); 
>> insert_hf("From: $var(my_from_hdr)\r\n", "To");" has no effect.
>>
>> Any advice, since 1.3.1 doesn't seem to help also?
>>
>> Andreas
>>
>>
>> Bai Shi wrote:
>>> Hi Andreas,
>>> I called without any branches.
>>>
>>> Bogdan, I'd appreciate if you can spare sometime to look at this again.
>>> Rgds,
>>> Bai Shi
>>>
>>> -----Original Message-----
>>> From: Andreas Granig [mailto:agranig at sipwise.com] Sent: 2008年3月20日 
>>> 1:34
>>> To: Bogdan-Andrei Iancu
>>> Cc: Bai Shi; Thomas Gelf; users at openser.org
>>> Subject: Re: [OpenSER-Users] uac_replace_from and CANCEL
>>>
>>> Or, to be more specific, I call it from a route which is called by a 
>>> branch_route. Not sure if that matters.
>>>
>>> Andreas
>>>
>>> Andreas Granig wrote:
>>>> Bogdan,
>>>>
>>>> I just tested with 1.3.1, and there the From of the CANCEL is also 
>>>> NOT updated. A probably not so unimportant side-note is that I call 
>>>> uac_replace_from() from a branch_route.
>>>>
>>>> Andreas
>>>>
>>>> Bogdan-Andrei Iancu wrote:
>>>>> Hi Bai Shi,
>>>>>
>>>>> I just tested (to be sure no bugs are present) and in 1.3, the 
>>>>> CANCELs are automatically updated (the FROM header), as expected.
>>>>>
>>>>> Regards,
>>>>> Bogdan
>>>>>
>>>>> Bai Shi wrote:
>>>>>> Hi, Thomas,
>>>>>> This will do in openser 1.2, however, in openser 1.3 it won't do 
>>>>>> any help. The CANCEL will be sent out regardless what you have 
>>>>>> done to the request, but follow the information in the original 
>>>>>> INVITE. I tested it and suffered a lot ;(
>>>>>> Rgds,
>>>>>> BS
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: users-bounces at lists.openser.org 
>>>>>> [mailto:users-bounces at lists.openser.org] On Behalf Of Andreas Granig
>>>>>> Sent: 2008年3月13日 2:54
>>>>>> To: Thomas Gelf
>>>>>> Cc: users at openser.org
>>>>>> Subject: Re: [OpenSER-Users] uac_replace_from and CANCEL
>>>>>>
>>>>>> 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
>>>>>>>>
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