[sr-dev] siptrace inconsistency

[Daniel-Constantin Mierla]

Hi Federico,

were the received ack and cancel captured automatically in the old
version when sip trace was set for invite? There were many changes in
the past years, but I remember that the flag was mainly for outgoing
requests and matching replies of the transaction for which the flag was
set. For incoming requests sip_trace() function had to be used.

Based on your remark, I think that trace_tm_neg_ack_in() should not
check if the trace-is-off(). It should be set when trace-is-on and
that's it for the transaction.

Feel free to clarify (or propose) the wanted behaviour and then we can
work together to have it as expected. I used sip trace lately for
tracing all traffic (trace_mode=1), no longer doing any filtering for
transactions/dialogs.

Cheers,
Daniel

On 31.03.20 09:09, Federico Cabiddu wrote:
> Hi all,
> I've been recently testing 5.3.x/master siptrace module, in particular
> the new trace mode "t" vs the legacy flag + sip_trace() mode and I've
> found some issues with the handling of CANCEL. Specifically, I've
> tested the following scenarios:
> 1) sip_trace_mode("t") on the initial INVITE only: received ACK for
> negative replies not captured
> 2) sip_trace_mode("t") on the initial INVITE and on neg ACK: received
> ACK captured twice
> 3) setflag and sip_trace() on the initial INVITE only: received CANCEL
> and ACK not captured (outgoing yes)
> 4) setflag and sip_trace() on the initial INVITE and ACK: received
> CANCEL not captured, received ACK captured twice
> 5) setflag and sip_trace() for each message (legacy): received CANCEL
> and 200 captured twice, received ACK captured twice
>
> Digging into the module's code the "culprit" looks to be trace_is_off
> function
> (https://github.com/kamailio/kamailio/blob/2768f8ce1cf6da242674e7e40c8e76eb6c630f6b/src/modules/siptrace/siptrace.c#L66)
> and the places where it is called.
> E.g.: for the case 1), when a negative reply is
> received, trace_tm_neg_ack_in is called, which calls inside
> trace_is_off
> (https://github.com/kamailio/kamailio/blob/2768f8ce1cf6da242674e7e40c8e76eb6c630f6b/src/modules/siptrace/siptrace.c#L1661),
> which cannot be true unless the ACK has been marked for capture in the
> script, in which case it will be capture twice (case 2). The same
> applies to the CANCEL for case 3), in trace_onreq_out (callback
> for TMCB_E2ECANCEL_IN) trace_is_off because the incoming message is
> not flagged. Case 3) should theoretically behave like case 1)
> according to
> commit https://github.com/kamailio/kamailio/commit/40e09d8625184f19ff5666a2848cbb8c6212db26.
>
> I'm not really sure if (and how) modify the trace_is_off function or
> not calling it in specific cases. E.g.: why calling it
> in trace_tm_neg_ack_in? This callback is set when we explicity want to
> trace a transaction, so why checking inside if tracing is on? Maybe
> I'm missing something, but I think that probably the different
> behaviors of the modes should be better specified/decided.
>
> Best regards,
>
> Federico
>
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-- 
Daniel-Constantin Mierla -- www.asipto.com
www.twitter.com/miconda -- www.linkedin.com/in/miconda

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