Incoming INVITE not creating dialog resulting in SIPREC SDP not being generated.

[groyal]

OpenSIPS version you are running

root@greg-ThinkPad-Yoga-370:/var/log# opensips -V
version: opensips 3.4.3 (x86_64/linux)
flags: STATS: On, EXTRA_DEBUG, DISABLE_NAGLE, USE_MCAST, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, HP_MALLOC, DBG_MALLOC, FAST_LOCK-ADAPTIVE_WAIT
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144, MAX_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535
poll method support: poll, epoll, sigio_rt, select.
git revision: f363f66
main.c compiled on 15:35:07 Jan 10 2024 with gcc 11

Describe the bug
I am trying to get a siprec example working with opensips 3.4.3 and I have run into a problem where dialogs are not being created from an INVITE. My environment is simple, Ubuntu 22.04.03 jammy running opensips and two phones registered, Grandstream GXP2170 and microsip soft client. So nothing special. The RTPproxy works fine and can see from Wireshark it is working.
However, dialogs are not being created from INVITE from either phone.
My understanding is that this is needed for SIPREC to build an SDP to the SRS. Without this Siprec fails (see logs).

Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17962]: DBG:b2b_entities:b2b_prescript_f: start - method = INVITE
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17962]: DBG:b2b_entities:b2b_prescript_f: start - method = INVITE
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17962]: DBG:b2b_entities:b2b_prescript_f: <uri> host:port [192.168.1.241][0]
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17962]: DBG:b2b_entities:b2b_prescript_f: <uri> host:port [192.168.1.241][0]
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17962]: DBG:b2b_entities:b2b_prescript_f: Not an inside dialog request- not interested.
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17962]: DBG:b2b_entities:b2b_prescript_f: Not an inside dialog request- not interested.
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17965]: DBG:b2b_entities:b2b_prescript_f: start - method = INVITE
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17965]: DBG:b2b_entities:b2b_prescript_f: start - method = INVITE
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17965]: DBG:b2b_entities:b2b_prescript_f: <uri> host:port [192.168.1.241][0]
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17965]: DBG:b2b_entities:b2b_prescript_f: <uri> host:port [192.168.1.241][0]
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17965]: DBG:b2b_entities:b2b_prescript_f: Not an inside dialog request- not interested.
Jan 12 10:53:36 greg-ThinkPad-Yoga-370 opensips[17965]: DBG:b2b_entities:b2b_prescript_f: Not an inside dialog request- not interested.

I tracked to here, where a dialog is not created because it cant read the to_tag so it says not interested.

https://github.com/OpenSIPS/opensips/blob/master/modules/b2b_entities/dlg.c
about line 950

	to_tag = get_to(msg)->tag_value;
	if(to_tag.s == NULL || to_tag.len == 0)
	{
		LM_DBG("Not an inside dialog request- not interested.\n");
		return SCB_RUN_ALL;
	}

I have attached a pcap of the SIP INVITE Message 192.168.1.100 -> 192.168.1.241 (opensips)

To Reproduce
Make simple phone call to other devices and generate an INVITE.
This INVITE is passed to opensips which then fails to read the TO_TAG in the message to generate a dialog.

Expected behavior
Dialog Created

Relevant System Logs
opensips.log
opensipscfg.zip

OS/environment information
root@greg-ThinkPad-Yoga-370:/var/log# cat /proc/version
Linux version 6.5.0-14-generic (buildd@lcy02-amd64-110) (x86_64-linux-gnu-gcc-12 (Ubuntu 12.3.0-1ubuntu122.04) 12.3.0, GNU ld (GNU Binutils for Ubuntu) 2.38) #1422.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Nov 20 18:15:30 UTC 2
root@greg-ThinkPad-Yoga-370:/var/log#
root@greg-ThinkPad-Yoga-370:/var/log# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 22.04.3 LTS
Release: 22.04
Codename: jammy
siprec_pcap.zip

[razvancrainea]

I think you are looking in the wrong place, the logs you are pointing out simply say that the initial INVITE is not part of a B2B dialog, which is not.
Later on, the dialog is properly created:

DBG:dialog:build_new_dlg: new dialog 0x7ff72e888ef0 (c=725452192-5060-6@BJC.BGI.B.BAE,f=sip:100@192.168.1.241,t=sip:200@192.168.1.241,ft=1909576740) on hash 1356

Your problem, however, is that you have not engage rtpengine or rtpproxy for the call, hence:

Jan 12 11:20:48 greg-ThinkPad-Yoga-370 opensips[17965]: ERROR:rtp_relay:rtp_relay_copy_offer: rtp not established!
Jan 12 11:20:48 greg-ThinkPad-Yoga-370 opensips[17965]: ERROR:siprec:src_start_recording: could not start recording!
Jan 12 11:20:48 greg-ThinkPad-Yoga-370 opensips[17965]: ERROR:siprec:tm_start_recording: cannot start recording!

Nevertheless, this is not a problem in OpenSIPS but rather a usage issue, therefore I will close this ticket.
If you have further questions about usage, please use our mailing list.