14 Nov
2024
14 Nov
'24
3:39 p.m.
Hi,
I am trying to use dlg_req_within() for a 3pcc-style call setup, to set up media via a
reinvite:
1. Store original SDP offer from caller in $dlg_var()s;
2. Later, after e2e ACK is processed for initial INVITE transaction, send reinvite to
callee using dlg_req_within(). I call rtpengine_offer() and feed it the original SDP offer
(via read_sdp_pv modparam), and take the RTPEngine-transformed SDP and feed that to
dlg_req_within():
dlg_req_within("callee", "INVITE", "application/sdp",
"$var(sdp_from_rtpengine)");
3. I have found that event_route[tm:local-response] does not allow me to capture the 200
OK / SDP answer to this reinvite; it is internally absorbed.
However, it is possible to arm an onreply_route in event_route[tm:local-request], to
receive the 200 OK:
event_route[tm:local-request] {
if(method == "INVITE" && has_body("application/sdp"))
t_on_reply("REINVITE_REPLY");
}
4. My intent is for this reinvite reply handler to set off a reinvite to the caller side:
onreply_route[REINVITE_REPLY] {
if(method == "INVITE" && has_body("application/sdp")
&& t_check_status("200")) {
...
$var(rtpengine_use_this_sdp) = $rb;
rtpengine_answer("...");
dlg_req_within("caller", "INVITE",
"application/sdp", "$var(sdp_from_rtpengine)");
}
This ensures proper relay symmetry. Otherwise, the caller will continue to send RTP to the
previous upstream endpoint of the call, prior to any reinvite.
However, dlg_req_within() doesn't work in this later context, even though the
documentation says it can be used from ANY_ROUTE. Kamailio doesn't complain, there is
no error. It just doesn't initiate a reinvite to the caller.
I considered the possibility that this may be because the calling scope is that of a
pending reinvite transaction to the callee, but there is no obvious way to defer that into
the future. If I send it to an async task worker, the transaction scope required for
dlg_req_within() to know which dialog it's operating on will be lost.
Any ideas appreciated, and thank you in advance!
-- Alex
--
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800
14 Nov
14 Nov
3:52 p.m.
Hi,
Did you try to lookup the dialog[1] before calling dlg_req_within()?
[1]
https://kamailio.org/docs/modules/devel/modules/dialog.html#dialog.f.dlg_get
Thanks,
Carsten
--
Schöne Grüße aus Hamburg, dem Tor zur Welt,
Carsten Bock
Baron-Voght-Str. 128a I 22607 Hamburg I Germany
T +49 179 2021244 I carsten(a)bock.info
LinkedIn: https://www.linkedin.com/in/carstenbock/
Alex Balashov via sr-users <sr-users(a)lists.kamailio.org> schrieb am Do.,
14. Nov. 2024, 21:44:
Hi,
I am trying to use dlg_req_within() for a 3pcc-style call setup, to set up
media via a reinvite:
1. Store original SDP offer from caller in $dlg_var()s;
2. Later, after e2e ACK is processed for initial INVITE transaction, send
reinvite to callee using dlg_req_within(). I call rtpengine_offer() and
feed it the original SDP offer (via read_sdp_pv modparam), and take the
RTPEngine-transformed SDP and feed that to dlg_req_within():
dlg_req_within("callee", "INVITE", "application/sdp",
"$var(sdp_from_rtpengine)");
3. I have found that event_route[tm:local-response] does not allow me to
capture the 200 OK / SDP answer to this reinvite; it is internally absorbed.
However, it is possible to arm an onreply_route in
event_route[tm:local-request], to receive the 200 OK:
event_route[tm:local-request] {
if(method == "INVITE" && has_body("application/sdp"))
t_on_reply("REINVITE_REPLY");
}
4. My intent is for this reinvite reply handler to set off a reinvite to
the caller side:
onreply_route[REINVITE_REPLY] {
if(method == "INVITE" && has_body("application/sdp")
&&
t_check_status("200")) {
...
$var(rtpengine_use_this_sdp) = $rb;
rtpengine_answer("...");
dlg_req_within("caller", "INVITE",
"application/sdp",
"$var(sdp_from_rtpengine)");
}
This ensures proper relay symmetry. Otherwise, the caller will continue to
send RTP to the previous upstream endpoint of the call, prior to any
reinvite.
However, dlg_req_within() doesn't work in this later context, even though
the documentation says it can be used from ANY_ROUTE. Kamailio doesn't
complain, there is no error. It just doesn't initiate a reinvite to the
caller.
I considered the possibility that this may be because the calling scope is
that of a pending reinvite transaction to the callee, but there is no
obvious way to defer that into the future. If I send it to an async task
worker, the transaction scope required for dlg_req_within() to know which
dialog it's operating on will be lost.
Any ideas appreciated, and thank you in advance!
-- Alex
--
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800
__________________________________________________________
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sr-users(a)lists.kamailio.org
To unsubscribe send an email to sr-users-leave(a)lists.kamailio.org
Important: keep the mailing list in the recipients, do not reply only to
the sender!
4:02 p.m.
Hi Carsten,
No, I didn't. It didn't occur to me that this function calibrates the dialog
scope of the next call, which is the missing ingredient inside a reply handler that is
armed out of a more general, global event route. Thank you for this!
-- Alex
On Nov 14, 2024, at 3:52 pm, Carsten Bock
<carsten(a)bock.info> wrote:
Hi,
Did you try to lookup the dialog[1] before calling dlg_req_within()?
[1] https://kamailio.org/docs/modules/devel/modules/dialog.html#dialog.f.dlg_get
Thanks,
Carsten
--
Schöne Grüße aus Hamburg, dem Tor zur Welt,
Carsten Bock
Baron-Voght-Str. 128a I 22607 Hamburg I Germany
T +49 179 2021244 I carsten(a)bock.info
LinkedIn: https://www.linkedin.com/in/carstenbock/
Alex Balashov via sr-users <sr-users(a)lists.kamailio.org> schrieb am Do., 14. Nov.
2024, 21:44:
Hi,
I am trying to use dlg_req_within() for a 3pcc-style call setup, to set up media via a
reinvite:
1. Store original SDP offer from caller in $dlg_var()s;
2. Later, after e2e ACK is processed for initial INVITE transaction, send reinvite to
callee using dlg_req_within(). I call rtpengine_offer() and feed it the original SDP offer
(via read_sdp_pv modparam), and take the RTPEngine-transformed SDP and feed that to
dlg_req_within():
dlg_req_within("callee", "INVITE", "application/sdp",
"$var(sdp_from_rtpengine)");
3. I have found that event_route[tm:local-response] does not allow me to capture the 200
OK / SDP answer to this reinvite; it is internally absorbed.
However, it is possible to arm an onreply_route in event_route[tm:local-request], to
receive the 200 OK:
event_route[tm:local-request] {
if(method == "INVITE" && has_body("application/sdp"))
t_on_reply("REINVITE_REPLY");
}
4. My intent is for this reinvite reply handler to set off a reinvite to the caller
side:
onreply_route[REINVITE_REPLY] {
if(method == "INVITE" && has_body("application/sdp")
&& t_check_status("200")) {
...
$var(rtpengine_use_this_sdp) = $rb;
rtpengine_answer("...");
dlg_req_within("caller", "INVITE",
"application/sdp", "$var(sdp_from_rtpengine)");
}
This ensures proper relay symmetry. Otherwise, the caller will continue to send RTP to
the previous upstream endpoint of the call, prior to any reinvite.
However, dlg_req_within() doesn't work in this later context, even though the
documentation says it can be used from ANY_ROUTE. Kamailio doesn't complain, there is
no error. It just doesn't initiate a reinvite to the caller.
I considered the possibility that this may be because the calling scope is that of a
pending reinvite transaction to the callee, but there is no obvious way to defer that into
the future. If I send it to an async task worker, the transaction scope required for
dlg_req_within() to know which dialog it's operating on will be lost.
Any ideas appreciated, and thank you in advance!
-- Alex
--
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800
__________________________________________________________
Kamailio - Users Mailing List - Non Commercial Discussions --
sr-users(a)lists.kamailio.org
To unsubscribe send an email to sr-users-leave(a)lists.kamailio.org
Important: keep the mailing list in the recipients, do not reply only to the sender!
--
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800
58
days inactive
58
days old
2 comments
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participants (2)
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Alex Balashov -
Carsten Bock