[SR-Users] t_check_trans() exits route execution if transaction is found

[Daniel-Constantin Mierla]

Hello,

this behaviour is intended to absorb the retransmissions -- if the
transaction is found, the request was already processed (could be by
another application process) and makes no sense to process it again . If
you don't use t_check_trans(), it will be anyhow discarded later when
t_relay() or t_newtran() is executed, because the transaction is already
in memory -- but usually that means you consumed some extra cpu/memory
to get there.

Cheers,
Daniel

On 07/07/16 09:59, Sebastian Damm wrote:
> Hi,
>
> on one of our systems we are checking a few times whether a
> transaction already exists. We noticed that route execution stops if
> the transaction is found. And after looking into the code, we found
> that it seems to be intended like this.
>
> From tm.c:
>         int t_check_trans(struct sip_msg* msg)
>         {
>                 if (msg->first_line.type==SIP_REPLY) {
>                [..]
>                 } else {
>                         switch(t_check_msg(msg, 0)){
>                                 [..]
>                                 case 1: /* found */
>                                        [..]
>                                        return 0; /* exit from the script */
>                         }
>                 }
>         }
>
> Can anybody explain, why script execution should stop when a running
> transaction is found? I would expect that then the function returns 1
> so I can use it in my if statement and continue with my routing
> script.
>
> Thanks already for an explanation,
> Sebastian
>
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-- 
Daniel-Constantin Mierla
http://www.asipto.com - http://www.kamailio.org
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