[OpenSIPS-Users] Issue with 'To' tag and t_reply

Thu Mar 26 14:23:26 EST 2020

The problem is that I need to go through a list of SIP servers, analyze
response of each of them and if it's an error like 4XX, 5XX or 6XX I need
to send appropriate response to originating server. Let's say I'm not only
adding a Reason field but upon receipt of 404 Not Found I want to respond
with 480 Temporarily Unavailable with Reason: Q.850;Cause=41 for example?
But Server B first replied with 183 Session Progress playing back a message
'Sorry, you need to top up your account' and then replied with SIP 402
Payment Required. I had to proxy 183 Session Progress back to Server A so
its SIP client could hear that message and then I'd like to signal 480
Temporarily Unavailable - but I can't as OpenSIPS is using completely
different To tag.

I can't do this in onreply_route as I'm going through a list of SIP servers
(upstreams or downstreams), so it definitely needs to be done from failure
route, as far as I understand, and yes, I'm matching against 4XX, 5XX and
6XX codes and I need to reply with 480 Temporarily Unavailable in most
cases so Server A would have a possibility to do failover to any other
server in that case. I don't want to just proxy 4XX, 5XX or 6XX response to
it.

I've figured out why I have two 404 responses in my original call log - I
was using sl_send_reply instead of t_reply and it was using original To tag
but only on second attempt.

Regards,
Yury.

пт, 27 мар. 2020 г. в 01:02, Yury Kirsanov <y.kirsanov at gmail.com>:

> Hi,
> As per my original email:
> 1. I was doing exactly as you suggested, in failure_route I'm using
> t_reply("404","Not Found") and it comes out with a wrong To: tag.
> 2. I don't need to proxy response from server B, I need to analyze its
> response and send a response to server A according to my needs.
>
> Currently it seems that t_reply is not using same To tag if 183 Session
> Progress has been proxied, which is strange as I have dialog running.
>
> Regards,
> Yury.
>
> чт, 26 мар. 2020 г. в 19:13, Yury Kirsanov <y.kirsanov at gmail.com>:
>
>> Hi,
>> I'm using an OpenSIPS as a proxy between two servers. First one is
>> sending SIP INVITE to OpenSIPS, then OpenSIPS forwards request to second
>> server. I'm creating a dialog on initial INVITE. Second server then replies
>> with SIP 183 Session Progress, plays back a message and then responds with
>> 4XX code, for example SIP 404 Not Found (indicating that number dialed is
>> disconnected). In OpenSIPS I'm receiving that reply and in failure_route
>> I'd like to change that code to a bit different SIP 404, so I'm using
>> following code:
>>
>> append_to_reply("Reason: Q.850;cause=1");
>> t_reply("404","Not Found");
>> exit;
>>
>> But in this case I can see that OpenSIPS generates additional branch (???
>> not sure here) with different "To" tag and pushes it out and then forwards
>> original reply SIP packet even though I have an exit statement in my
>> failure_route. I tried to do sl_send_reply and behavior is pretty much the
>> same. Can someone let me know what I may be doing wrong? I need correct
>> "To" tag to be used (based on 183 Session Progress message from server B
>> and passed to server A previously) and second 404 shouldn't be forwarded
>> out.
>>
>> Here's an example of a call with my explanations
>>
>> Initial invite from server A, no 'to tag' as expected:
>>
>> INVITE sip:XXXXXXXXX at B.B.B.B SIP/2.0
>> Max-Forwards: 67
>> To: "XXXXXXXXX" <sip:XXXXXXXXX at B.B.B.B>
>> Call-ID: 469A5568-E092-4038-B1B8-13AC9B9571CA
>> Via: SIP/2.0/UDP A.A.A.A:5060;rport;branch=z9hG4bK773616538
>> From: "YYYYYYYYY" <sip:YYYYYYYYY at A.A.A.A>;tag=117583367
>> CSeq: 1741310 INVITE
>> User-Agent: User Agent
>> Contact: <sip:YYYYYYYYY at A.A.A.A:5060>
>> Allow: ACK, INVITE, BYE, CANCEL, REGISTER, REFER, OPTIONS, INFO,
>> SUBSCRIBE, NOTIFY
>> Date: Thu, 26 Mar 2020 07:54:55 GMT
>> Content-Type: application/sdp
>> Content-Length: 250
>>
>> v=0
>> o=dcom 1585209295 1585209295 IN IP4 A.A.A.A
>> s=SIP Call
>> c=IN IP4 A.A.A.A
>> t=0 0
>> m=audio 15340 RTP/AVP 8 0 18 101
>> a=rtpmap:8 PCMA/8000
>> a=rtpmap:0 PCMU/8000
>> a=rtpmap:18 G729/8000
>> a=fmtp:18 annexb=no
>> a=rtpmap:101 telephone-event/8000
>>
>> Response from OpenSIPS:
>>
>> SIP/2.0 100 Giving a try
>> To: "XXXXXXXXX" <sip:XXXXXXXXX at B.B.B.B>
>> Call-ID: 469A5568-E092-4038-B1B8-13AC9B9571CA
>> Via: SIP/2.0/UDP
>> A.A.A.A:5060;received=A.A.A.A;rport=5060;branch=z9hG4bK773616538
>> From: "YYYYYYYYY" <sip:YYYYYYYYY at A.A.A.A>;tag=117583367
>> CSeq: 1741310 INVITE
>> Server: Server Signature
>> Content-Length: 0
>>
>> OpenSIPS has forwarded packet to Server B and Server B responded with 183
>> and assigned a 'To' tag:
>>
>> SIP/2.0 183 Session Progress
>> Via: SIP/2.0/UDP
>> A.A.A.A:5060;received=A.A.A.A;rport=5060;branch=z9hG4bK773616538
>> Call-ID: 469A5568-E092-4038-B1B8-13AC9B9571CA
>> From: "YYYYYYYYY" <sip:YYYYYYYYY at A.A.A.A>;tag=117583367
>> To: "XXXXXXXXX" <sip:XXXXXXXXX at B.B.B.B>;
>> *tag=0b49dc32-2c4b-413e-a349-c781a23d53b9*
>> CSeq: 1741310 INVITE
>> Server: PBX
>> Contact: <sip:B.B.B.B;did=d0a.99678f73>
>> Allow: OPTIONS, REGISTER, SUBSCRIBE, NOTIFY, PUBLISH, INVITE, ACK, BYE,
>> CANCEL, UPDATE, PRACK, REFER
>> Content-Type: application/sdp
>> Content-Length: 354
>>
>> v=0
>> o=- 1585209295 1585209297 IN IP4 B.B.B.B
>> s=Asterisk
>> c=IN IP4 B.B.B.B
>> t=0 0
>> a=rtpengine:673f999268ae
>> m=audio 32386 RTP/AVP 0 8 18 101
>> a=maxptime:150
>> a=rtpmap:0 PCMU/8000
>> a=rtpmap:8 PCMA/8000
>> a=rtpmap:18 G729/8000
>> a=rtpmap:101 telephone-event/8000
>> a=fmtp:18 annexb=no
>> a=fmtp:101 0-16
>> a=sendrecv
>> a=rtcp:32387
>> a=ptime:20
>>
>> Server B responds with SIP 404 after playing back message that number is
>> disconnected and I'm trying to reply to server A with custom Reason
>> message. To_tag is completely different from the To tag that has been
>> passed to server A after initial 183!!!
>>
>> SIP/2.0 404 Not Found
>> To: "XXXXXXXXX" <sip:XXXXXXXXX at B.B.B.B>;
>> *tag=a976.21514595b467be41a9b712a6b0b621d9*
>> Call-ID: 469A5568-E092-4038-B1B8-13AC9B9571CA
>> Via: SIP/2.0/UDP
>> A.A.A.A:5060;received=A.A.A.A;rport=5060;branch=z9hG4bK773616538
>> From: "YYYYYYYYY" <sip:YYYYYYYYY at A.A.A.A>;tag=117583367
>> CSeq: 1741310 INVITE
>> Reason: Q.850;cause=1;text="Number is disconnected"
>> Server: Server Signature
>> Content-Length: 0
>>
>> Of course, server A just ignores this message as it can't match 'To' tag
>> to its transaction. Now, for some reason, OpenSIPS forwards original reply
>> from Server B to Server A with the same 'To' tag as in 183 Session Progress:
>>
>> SIP/2.0 404 Not Found
>> Via: SIP/2.0/UDP
>> A.A.A.A:5060;received=A.A.A.A;rport=5060;branch=z9hG4bK773616538
>> Call-ID: 469A5568-E092-4038-B1B8-13AC9B9571CA
>> From: "YYYYYYYYY" <sip:YYYYYYYYY at A.A.A.A>;tag=117583367
>> To: "XXXXXXXXX" <sip:XXXXXXXXX at B.B.B.B>;
>> *tag=0b49dc32-2c4b-413e-a349-c781a23d53b9*
>> CSeq: 1741310 INVITE
>> Server: PBX
>> Allow: OPTIONS, REGISTER, SUBSCRIBE, NOTIFY, PUBLISH, INVITE, ACK, BYE,
>> CANCEL, UPDATE, PRACK, REFER
>> Reason: Q.850;cause=1
>> Content-Length:  0
>>
>> And at this point Server A can match this reply and responds with an ACK:
>>
>> ACK sip:XXXXXXXXX at B.B.B.B SIP/2.0
>> Via: SIP/2.0/UDP A.A.A.A:5060;rport;branch=z9hG4bK773616538
>> From: "YYYYYYYYY" <sip:YYYYYYYYY at A.A.A.A>;tag=117583367
>> To: "XXXXXXXXX" <sip:XXXXXXXXX at B.B.B.B>;
>> *tag=0b49dc32-2c4b-413e-a349-c781a23d53b9*
>> Call-ID: 469A5568-E092-4038-B1B8-13AC9B9571CA
>> CSeq: 1741310 ACK
>> Max-Forwards: 67
>> Contact: <sip:YYYYYYYYY at A.A.A.A:5060>
>> User-Agent: User Agent
>> Content-Length: 0
>>
>> I think that t_reply is creating a new transaction instead of using
>> existing one, but I'm not sure why and how to fix this?
>>
>> Thanks!
>>
>> Best regards,
>> Yury.
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opensips.org/pipermail/users/attachments/20200327/eb323244/attachment.html>