[Freeswitch-users] Incorrect reply to T.38 re-INVITE

[Michael Jerris]

I think we fixed this in 1.6 already.  Give it a try to confirm but i recall this one getting fixed.

> On Feb 19, 2016, at 2:24 PM, Tomasz Ostrowski <tomasz.o.ostrowski at gmail.com> wrote:
> 
> Hello,
> while testing FreeSWITCH 1.4.26 I stumbled upon old and seemingly ignored  
> problem when FreeSWITCH replies with SDP containing:
> 
> m=image 0 udptl t38
> m=image 0 udptl t38
> 
> when receiving re-INVITE with disabled audio media and enabled image media  
> (switching from audio to image). As far as I know this is correct way to  
> change media, from RFC 3264:
> 
> 8.1 Adding a Media Stream
> 
>    New media streams are created by new additional media descriptions
>    below the existing ones, or by reusing the "slot" used by an old
>    media stream which had been disabled by setting its port to zero.
> 
>    Reusing its slot means that the new media description replaces the
>    old one, but retains its positioning relative to other media
>    descriptions in  the SDP.  New media descriptions MUST appear below
>    any existing media sections.  The rules for formatting these media
>    descriptions are identical to those described in Section 5.
> 
>    When the answerer receives an SDP with more media descriptions than
>    the previous SDP from the offerer, or it receives an SDP with a media
>    stream in a slot where the port was previously zero, the answerer
>    knows that new media streams are being added.  These can be rejected
>    or accepted by placing an appropriately structured media description
>    in the answer.  The procedures for constructing the new media
>    description in the answer are described in Section 6.
> 
> This problem is mentioned in:
> https://freeswitch.org/jira/browse/FS-7037
> https://freeswitch.org/jira/browse/FS-6212
> 
> With reversed transmission direction (when FreeSWITCH receives FAX and  
> re-INVITES) re-INVITE contains only image media, but this is easier to  
> accept (https://freeswitch.org/jira/browse/FS-6954 -  correcting it caused  
> interoperability problems between FS versions), while not accepting  
> correct SDP by FreeSWITCH is really painful as it requires implementing  
> RFC non-compliant negotiation and probably adding special switch in  
> configuration to be interoperable.
> 
> Is this issue fixed in FreeSWITCH 1.6 (I cannot find any further  
> references in jira)?
> Could you give me any suggestions where to look in FreeSWITCH source code  
> (10k LOC sofia.c seems pretty complex)?
> 
> -- 
> TMSZ
> 
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services: 
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
> 
> Official FreeSWITCH Sites
> http://www.freeswitch.org
> http://confluence.freeswitch.org
> http://www.cluecon.com
> 
> FreeSWITCH-users mailing list
> FreeSWITCH-users at lists.freeswitch.org
> http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
> UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
> http://www.freeswitch.org