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 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.
SIP flow (up to the point when first UDP retransmission happens)
I apologise in advance for the bulky question and will be extremely thankful for any guidance.
Regards, Ivan
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 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:
- Calling set_uac_request() to define request parameters
- 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 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
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.netmailto: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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