9 May
2019
9 May
'19
1:58 a.m.
Hello Ivan,
this type of questions are better suited to our developer list, not the users list -
adding it to CC.
I haven't looked yet that deep into your previous e-mail, but have you already looked
e.g. to the dialog module? This does something similar, e.g. bridging an existing dialog.
It uses uac_req_t and a TM callback. You find the implementation in dlg_transfer.c, e.g.
function dlg_bridge(str *from, str *to, str *op, str *bd).
Cheers,
Henning
Am 08.05.19 um 09:26 schrieb Ivan Ribakov:
Anyone with module dev experience here who had to do something similar or used tm_load.h
interface for other purposes?
On 7 May 2019, at 16:39, Ivan Ribakov
<i.ribakov@zaleos.net<mailto:i.ribakov@zaleos.net>> wrote:
I’m working on a custom Kamailio module where I need to send new-dialog and in-dialog
requests on timer (hence I’m being forced to generate new messages from C code).
So far I’ve been using modules/tm/tm_load.h defined interface to generate messages and
handle callbacks. New dialog messages are sent and processed normally. To do that I’m:
1. Calling set_uac_request() to define request parameters
2. Calling tmb.t_request_outside() to send it outside any existing dialog
I was able to send in-dialog requests (or so I thought) in a similar fashion, but I soon
realised that responses to those requests were dropped because they couldn’t be matched
against any known existing transaction. I’m attaching log messages that I believe support
this theory and I’ve also observed UDP retransmissions.
tm [t_lookup.c:897]: t_reply_matching(): t_reply_matching: hash 50576 label 0 branch 0
tm [t_lookup.c:990]: t_reply_matching(): no matching transaction exists
tm [t_lookup.c:993]: t_reply_matching(): failure to match a transaction
tm [t_lookup.c:1088]: t_check_msg(): msg (0x5abcb50) id=1 global id=1 T end=(nil)
tm [t_reply.c:2195]: reply_received(): transaction not found - (branch -1)
The way I’m currently generating in-dialog requests is very similar to what
tmb.t_request_outside() does, the main difference being that I do the dialog setup
manually, based on the call-ID, cseq and from/to tags (I’m tracking transaction
identifiers separately) and then pass resulting uac_req_t to tmb.t_request_within() -
https://gist.github.com/IvanRibakov/3302cb286b1f4b786d109b406f2435a2
Now, the question part - does anyone know what I’m doing wrong/missing? As I mentioned,
when looking at the generated message bodies, they look ok to me (left - initial request
that started the dialog, right - first in-dialog request), so I’m guessing I’m missing
some Kamailio internal steps needed to register new transaction.
<kamailio_indialog_req.png>
SIP flow (up to the point when first UDP retransmission happens)
<PastedGraphic-1.png>
I apologise in advance for the bulky question and will be extremely thankful for any
guidance.
Regards,
Ivan
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