[asterisk-dev] DirectMedia or canreinvite=UPDATE - asterisk not handling 200K response with SDP for UPDATE sent

[Matthew Jordan]

On Wed, Sep 25, 2013 at 9:57 AM, bala murugan <fightwithme at gmail.com> wrote:

> Hi ,
>
>   I am working on asterisk 11.3 and noticed it is not handling the
> response for UPDATE when trying to do remote bridge using UPDATE . Any
> change in SDP that comes in 200 OK response is ignored and not update sent
> to connected peer .
>
> Looks like a bug - l looked at the code and i didnt see any code relevant
> to this scenarion.
>
> Can some provide me an input - i am planning to fix this .
>
>
It is not a bug, although it is a limitation of chan_sip.

Asterisk does not advertise support for the UPDATE method. The
handle_update_request method is quite explicit about this:

/*!
 * \brief bare-bones support for SIP UPDATE
 *
 * XXX This is not even close to being RFC 3311-compliant. We don't
advertise
 * that we support the UPDATE method, so no one should ever try sending us
 * an UPDATE anyway. However, Asterisk can send an UPDATE to change
connected
 * line information, so we need to be prepared to handle this. The way we
distinguish
 * such an UPDATE is through the X-Asterisk-rpid-update header.
 *
 * Actually updating the media session may be some future work.
 */

Additionally, Asterisk does not list UPDATE in its allowed methods:

#define ALLOWED_METHODS "INVITE, ACK, CANCEL, OPTIONS, BYE, REFER,
SUBSCRIBE, NOTIFY, INFO, PUBLISH"

The SIP UA sending an UPDATE request to Asterisk should not be doing so.

If you wanted to add full support for RFC 3311, that would be fine - but
doing so should be done in trunk, as it is an improvement to chan_sip.

Matt

-- 
Matthew Jordan
Digium, Inc. | Engineering Manager
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: http://digium.com & http://asterisk.org
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