Re: [Linphone-developers] BUG: Linphone building ACK wrong to a 200 - OK request

[Ramon Poca]

Replying to myself, so google archives for future reference:

Linphone (or rather osip/exosip) seems to use a transitional "101 -
Dialog establishment"  to set up the dialog. This one contains From
and To tags.
Our B2BUA was dropping the To: tag (or rather not generating a dialog
yet) when transmitting the 101.

When sending the 180, the B2BUA WAS generating the dialog. But
linphone does not update its already data taken from the 101 with the
new tag in the 180, or the same new tag on the 200.

The RFC does not state what to do (or I haven't found where) about
this, and I cannot consider it a "bug".

The solution has been to drop the 101 response on our B2BUA. This way,
the dialog is established by the sane 180 and linphone retrieves the
correct tag.




On Tue, May 29, 2012 at 2:11 PM, Ramon Poca <address@hidden> wrote:
> Hi There,
>
> I've been working with linphone for a while, and found what I think
> might be a bug. When doing calls that pass through a B2BUA, we found
> that Linphone was causing the routing to fail as it discarded the ;tag
> from the "To:" address, thus making it impossible for the proxy to
> reconstruct the dialog this (new) transaction belongs to.
> Other clients did it right and preserved the tag.
>
> PS: Submitting this duplicated, as I did change the addresses in
> from/to on the request but not on the response to anonimize them, but
> failed miserably :)
>
> The 200 + SDP that linphone gets is:
> SIP/2.0 200 OK.
> Record-Route: <sip:192.168.1.218:5070;lr=on>.
> Via: SIP/2.0/UDP 192.168.1.103:5060;rport=5060;branch=z9hG4bK998378342.
> From: <sip:address@hidden>;tag=1062731849.
> To: <sip:address@hidden>;tag=46DBD0486014455B6B1786963F5D3F74.
> Call-ID: 1398046168.
> CSeq: 20 INVITE.
> Max-Forwards: 69.
> Content-Type: application/sdp.
> User-Agent: Linphone/3.5.2 (eXosip2/3.6.0).
> X-Call-Id: 00002300002507.
> Contact: <sip:192.168.1.218:50060;transport=udp>.
> Content-Length: 482.
>
> The ACK linphone answers with:
>
> ACK sip:192.168.1.218:50060;transport=udp SIP/2.0.
> Via: SIP/2.0/UDP 192.168.1.103:5060;rport;branch=z9hG4bK1978960057.
> From: <sip:address@hidden>;tag=1062731849.
> To: <sip:address@hidden>.
> <<<<<<<<<<<<<<<< MISSING ;tag
> Call-ID: 1398046168.
> CSeq: 20 ACK.
> Contact: <sip:address@hidden>.
> Max-Forwards: 70.
> User-Agent: Linphone/3.5.2 (eXosip2/3.6.0).
> Content-Length: 0.
> .
>
> --
> Ramon Poca



-- 
Ramon Poca
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