[OpenSIPS-Users] OpenSIPS B2B / RFC 4579

[Carsten Bock]

Hi,

yes, you are right. The 404 does not come from the module itself. It is
triggered by the routing logic script as the b2b-related functions are not
triggered:

For the second REFER we have the following message in the log:
No dialog found, callid= [123 at 1.2.3.4], method=REFER
(from b2b_entitities/dlg.c, around line 969)

So this basically means, that for the second REFER, the b2b_logic module
does not find the initial session anymore.
Of course, I could treat the REFER from the routing logic and not from the
b2b_logic_request-route, but I think also the BYE might not be forwarded
anymore for the dialog in Step 1, as the dialog (which still exists) is not
found anymore.

I can share a trace tomorrow when I'm back in the lab.

Thanks,
Carsten
--
Carsten Bock I CTO & Founder

ng-voice GmbH

Trostbrücke 1 I 20457 Hamburg I Germany
T +49 40 524 75 93-40 | M +49 179 2021244 I www.ng-voice.com

Registry Office at Local Court Hamburg, HRB 120189
Managing Directors: Dr. David Bachmann, Carsten Bock


Am Mo., 29. März 2021 um 22:55 Uhr schrieb Nick Altmann <nick at altmann.pro>:

> Hi Carsten,
>
> "404 not here" can't be generated by the b2b module itself, it means that
> "404 not here" came from another part, I think from part C.
> Best way to check this is to capture sip traffic.
>
> --
> Nick
>
>
> пн, 29 мар. 2021 г. в 22:08, Carsten Bock <carsten at ng-voice.com>:
>
>> Hi,
>>
>> I have a question. I am trying to handle REFER requests as per RFC 4579
>> in OpenSIPS B2BUA Module.
>>
>> User-A wants to initiate a conference with User-B and User-C.
>>
>> step 1: Create Conference:
>> => INVITE sip:conference at conference-url
>> <= 200 OK
>> => ACK
>> --
>> This INVITE is forwarded to FreeSwitch to dial into a conference bridge.
>> --
>>
>> Step 2: Add User-B to conference:
>> => REFER sip:conference at conference-url (in-dialog), Refer-To: User-B
>> <= 202 Accepted
>> --
>> I want to send an INVITE to the same Conference Bridge in the first step
>> and an INVITE to User-B with a Replaces header and then bridge this
>> together.
>> It works until this step.
>> --
>>
>> Step 3: Add User-C to conference:
>> => REFER sip:conference at conference-url (in-dialog), Refere-To: User-C
>> <= 202 Accepted
>> --
>> Even though it is the same logic as for User-C, this fails with a "404
>> not here" created in the b2b module, as it fails to find the dialog from
>> Step 1?!?!?
>> --
>>
>> Config:
>> route{
>>     if (is_method("INVITE") && !has_totag()) {
>>         loose_route();
>>
>>         # create the server entity
>>         b2b_server_new("caller");
>>
>>         # create the initial client entity, to connect the caller with
>> the callee
>>         b2b_client_new("callee", $ru);
>>
>>         # initialize B2B session for the "refer" scenario
>>         b2b_init_request("refer");
>>         exit;
>>     }
>> }
>>
>> route[b2b_logic_request] {
>>     if ($rm != "REFER") {
>>         # for requests other than REFER, no special actions needs to be
>> done,
>>         # just pass the request to the peer
>>         b2b_pass_request();
>>         exit;
>>     }
>>
>>     if ($b2b_logic.ctx(conf) == "1") {
>>         b2b_send_reply(202, "Accepted");
>>
>>         $var(uri) =
>> "sip:"+$(hdr(Refer-To){nameaddr.uri}{uri.user}{s.select,0,;})+"@"+$(hdr(Refer-To){nameaddr.uri}{uri.host});
>>
>>         b2b_client_new("conf", "$ru");
>>
>>         # create the client entity corresponding to
>>         # the user specified in the 'Refer-To' header
>>             b2b_client_new("referee", $var(uri));
>>         # bridge the referrer's peer with the referee
>>         b2b_bridge("conf", "referee");
>>    }
>> }
>>
>> Nothing spectacular. Anyone any hints as, why the second REFER fails?
>>
>> Thanks,
>> Carsten
>>
>>
>> --
>> Carsten Bock I CTO & Founder
>>
>> ng-voice GmbH
>>
>> Trostbrücke 1 I 20457 Hamburg I Germany
>> T +49 40 524 75 93-40 | M +49 179 2021244 I www.ng-voice.com
>>
>> Registry Office at Local Court Hamburg, HRB 120189
>> Managing Directors: Dr. David Bachmann, Carsten Bock
>> _______________________________________________
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