[SR-Users] Dialog - timeout for dlg with CallID

[Julien Chavanton]

This problem may not affect all the match mode, not sure as I did not
test/the default dlg_match_mode.

This could be the reason why it was not detected before.

Anyhow, the fix I have in mind may prevent several pitfalls, in case
there was more than one problem, lets see if my assumption is correct.


On Fri, Sep 25, 2020 at 6:15 PM Julien Chavanton <jchavanton at gmail.com>
wrote:

> It seems I found the problem and I have a fix.
>
> The root cause is probably that the locally generated 408 is not updating
> the dialog to-tag.
>
> However, always checking for a to-tag match, before a non to-tag match
> will fix any such issue.
>
> I will prepare a merge request on Monday to start discussing the option
> always matching to-tag first.
>
> On Fri, Sep 25, 2020 at 11:27 AM Julien Chavanton <jchavanton at gmail.com>
> wrote:
>
>> I did catch the logs, and after looking at the trace, it seems like
>> dialog mismatch with a serial forking scenario :
>>
>> - log line 3 is telling us that a NO-ACK disconnection should be triggered
>> - log line 1-2 is telling us what happened when the ACK was received in
>> dlg_onroute(), oddly enough state 5 was old and new, could it be a
>> mismatch/confusio with the previous dialog, looking in this direction ...
>>
>> 1: 2020-09-25T16:30:16.896: dialog [dlg_handlers.c:1273]:
>> extra_ack_debug_info(): [ACK][1] state not changed >>>
>> call-id[562419_125824138_2072238224] to-tag[<sip:+14019991904 at anon.com
>> >;tag=gK02b68836]
>> 2: 2020-09-25T16:30:16.896: dialog [dlg_handlers.c:1440]: dlg_onroute():
>> [ACK] state not changed old[5]new[5]
>> ...
>> 3: 2020-09-25T16:32:22.674: dialog [dlg_hash.c:247]: dlg_clean_run():
>> dialog disconnection no-ACK
>> call-id[562419_125824138_2072238224][1601051416]<[1601051542 - 60]
>>
>>
>> After looking at the pcap trace, call-id 562419_125824138_2072238224 was
>> involved in serial forking :
>>
>> call attempt #1
>>
>> X >> INVITE >> Y   // no to-tag
>> X << 100
>> ...
>> X << 408           // to-tag=594d50c3218065a60bb91fd47a70fbc1-59edef02
>> (locally generated)
>> X >> ACK           // to-tag=594d50c3218065a60bb91fd47a70fbc1-59edef02
>>
>> call attempt #2
>>
>> X >> INVITE >> Z   // no to-tag
>> X << 100
>> X << 200    << Z   // to-tag=gK02b68836
>> X >> ACK    >> Z   // to-tag=gK02b68836 (Should be state old[3]new[4], I
>> wonder how it could possibly be state old[5]new[5])
>>
>>
>>
>> I did look at several occurrences and there is always a locally generated
>> 408/to-tag before, seems like I have a good lead to investigate further.
>>
>>
>>
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