[sr-dev] recursive calls to failure_route strange behavior

[Daniel-Constantin Mierla]

On 20.11.2009 16:57 Uhr, Michal Matyska wrote:
> Daniel-Constantin Mierla píše v Pá 20. 11. 2009 v 16:53 +0100:
>   
>> On 20.11.2009 16:38 Uhr, Daniel-Constantin Mierla wrote:
>>     
>>> On 20.11.2009 9:53 Uhr, Miklos Tirpak wrote:
>>>       
>>>> On 11/20/2009 12:58 AM, Andres Moya wrote:
>>>>         
>>>>> Dear all!
>>>>>
>>>>> Please help. I have problem dealing with recursive call in failure 
>>>>> route.
>>>>>
>>>>> this route happen first time for authentication to external SIP 
>>>>> provider (react on code 401), then it have response 480 i want to 
>>>>> direct traffic to another operator via cr_route.
>>>>>
>>>>> First i relay INVITE and getting 401, then sending authentication, 
>>>>> but provider gives 480. I can see it in a dump of SIP session. But 
>>>>> my failure_route still thinking that reply code is 401 on second 
>>>>> reply. Maybe because i dont understand well how branches concept 
>>>>> work here? Or using kamailio 3.0? ;) Looks like it give me status 
>>>>> code of first reply and ignoring actual code in reply. :( I don't 
>>>>> know if it something with development version or my own 
>>>>> misunderstanding. sorry
>>>>>           
>>>> This is correct, the proxy must choose one of the two responses to 
>>>> forward and 401 has higher precedence than 480 (RFC3261, 16.7: 
>>>> "Choosing the best response"). The failure route always works on the 
>>>> selected response as opposed to the last response received.
>>>>         
>>> I think this is wrong imo, if I got it right from your email, because 
>>> the failure route should work on a selected reply from the last set of 
>>> branches in serial forking.
>>>
>>> Do you say that if I get 301 with couple of contacts, then in failure 
>>> route I create new branches, relay, all failed because of timeout 
>>> and/or busy, I get back in failure route with the 301?
>>>
>>> I cannot drop all replies because maybe the reply I want to be sent 
>>> back to caller is from a previous branch. Think at:
>>>
>>> A calls B
>>> B phone gives busy
>>> B has redirect to C in such case
>>> C phone gives timeout
>>> C has now redirect to voice mail
>>> Voice mail returns server failure
>>>
>>> If I need to drop the replies then I will send the 500 reply which is 
>>> wrong.
>>>       
>> ... actually, while it might be questionable whether to select the reply 
>> to be sent back to caller from last serial forking set of branches or 
>> from entire set of branches, triggering failure route should be with a 
>> reply from last set of branches, otherwise you cannot take the right 
>> decision for new branches.
>>     
>
> If I understand correctly, then whenever you start above mentioned "new
> set of branches" just call t_drop_replies() and you are done.
>   
i said "questionable about selection of reply to send back but not about 
what code is presented to failure route". So yes, if I want only from 
last set of branches, it is ok what you say. But if not, then you are 
screwed up with serial forking logic.

the t_drop_replies() drops all branches, even there were two or more 
serial forking steps, not the replies from the last set of branches -- I 
checked the code. It just not look coherent.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
* http://www.asipto.com/