[SR-Users] Request-URI in fail route

[Daniel-Constantin Mierla]

Hello,

On 3/15/12 7:05 PM, Jan Klepal wrote:
> Hello Daniel,
>
> On Thursday 15 of March 2012 11:59:32 you wrote:
>>> First problem I encountered is that I can't check $rU in failure_route (it
>>> is always set to original Request-URI - bob). Is this normal behavior or
>>> am I missing something? Because of that I have to set divert destination
>>> in branch route.
>> in failure route you have access to the value of r-uri before getting to
>> any branch_route or failure_route. You can use an avp to store the value
>> you would like to check later in tm specific routes.
>>
> Thanks for confirming usage of avp.
>
>>> Second problem is when Carol's no-answer forward to Dave happens. Then
>>> add_diversion adds invalid diversion header because it uses Request-URI
>>> which is still set to bob.
>> You can set the r-uri to the value you want before calling
>> add_diversion, after that set it to what you want to be the destination.
>>
> I am not able to make this working... not sure if I follow you correctly. So I
> tried following minimal config:
>
> route {
>      if(is_method("REGISTER")) {
>          save("location");
>          exit;
>      }
>      lookup("location");
>      t_set_fr(5000);
>      t_on_failure("FAIL_ONE");
>      t_relay();
> }
>
> failure_route[FAIL_ONE] {
>      add_diversion("no-answer");
>      rewiteuser("carol");
>      lookup("location");
>      t_on_failure("FAIL_TWO");
>      t_relay();
> }
>
> failure_route[FAIL_TWO] {
>      rewriteuser("carol");
>      add_diversion("no-answer");
>      rewiteuser("dave");
>      lookup("location");
>      t_relay();
> }
>
> First failure route works correctly, it adds diversion header.
>
> However in second failure route diversion header is not appended to SIP packet
> at all (no matter if I try to overwrite r-uri). In case I overwrite r-uri in
> first failure route before calling add_diversion it still uses original r-uri.
> Same result changing r-uri with $ru or even with $rU instead of rewiteuser
> function.
>
> There is also problem in case of cross redirect (B->C and C->B)... secondary
> invites end with 500 Internal server error from UA (probably because it gets
> invite with same callid and tags as original invite).
>
> I think I need to use B2BUA to make multiple forwards working.
I checked the sources of diversion header -- add_diversion is actually 
using the incoming URI, not the updated one.

You better use insert_hf(...) from textops module to add the diversion 
header:

http://kamailio.org/docs/modules/stable/modules_k/textops.html#id2498304

For the loop, yes, that is client side. You can keep the list of 
destinations in avps and then check in config if a new destination was 
already tried and then reply 404 not found or something else from Kamailio.

Cheers,
Daniel


-- 
Daniel-Constantin Mierla
Kamailio Advanced Training, April 23-26, 2012, Berlin, Germany
http://www.asipto.com/index.php/kamailio-advanced-training/