Hi,

I have a tcpdump capture but the traffic is encrypted. So it won’t help you.

I have a clue how it happened:

When the first 200 response was received, kamailio successfully matched a transaction:

Jul 23 00:40:14  /usr/sbin/kamailio[570]: DEBUG: tm [t_lookup.c:972]: DEBUG: t_reply_matching: hash 51776 label 624824282 branch 2

Jul 23 00:40:14  /usr/sbin/kamailio[570]: DEBUG: tm [t_lookup.c:1032]: DEBUG: t_reply_matching: reply matched (T=0x7fb52d367f50)!

But when the locally generated 408 happened, kamailio failed to match a transaction:

Jul 23 00:40:44 /usr/sbin/kamailio[583]: DEBUG: tm [t_lookup.c:972]: DEBUG: t_reply_matching: hash 51776 label 624824282 branch 0

Jul 23 00:40:44 /usr/sbin/kamailio[583]: DEBUG: tm [t_lookup.c:1066]: DEBUG: t_reply_matching: no matching transaction exists

Because no transaction was matched, kamailio simply forwarded the response.

I’ll modify this behaviour in the source code. After receiving the first final response, there is no reason to keep the fr_timer running on other branches, right?

Cheers,

Allen

From: sr-users-bounces@lists.sip-router.org [mailto:sr-users-bounces@lists.sip-router.org] On Behalf Of Daniel-Constantin Mierla
Sent: Wednesday, 23 July 2014 10:41 p.m.
To: Kamailio (SER) - Users Mailing List
Subject: Re: [SR-Users] MESSAGE forking bug(?)

Hello,

can you get the sip traffic with ngrep on kamailio server? It can be taken with:

ngrep -d any -qt -W byline port 5060

Cheers,
Daniel

On 23/07/14 03:08, Allen Zhang wrote:

Hi,

I believe there is a bug on MESSAGE forking.

Test scenario:

User A has two records in the location table, with different instance ids: 111 and 222.

One of user A’s instance is killed, hence 222 is not reachable.

User B send a MESSAGE to user A.

Kamailio forked the MESSAGE.

Kamailio got a ‘200 Message delivered’ response from 111 and forwarded it to user B.

The MESSAGE forked to 222 timed out. Kamailio send a ‘408 Time out’ to user B.

This violates RFC 3428 section 4. It states that the forking UAS should only send ONE final response to the sender UAC.

Forking is done by t_relay(), and the registrar parameter ‘append_branches’ is set to default value 1.

Did I do something wrong, or there is a bug?

Regards,

Allen

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