25 Sep
2020
25 Sep
'20
9:20 p.m.
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(a)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(a)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@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.
>
>
>