[asterisk-dev] Porting chan_sip patches res_pjsip

[Joshua Colp]

On Wed, Apr 12, 2017, at 05:53 PM, Steve Murphy wrote:
> Hello, I must admit, as a beginner at this, that I have a lot to learn.
> 
> I have written a module to handle some statistics gathering, and it works
> fine,
> but my next priority patch leaves me quite puzzled.
> 
> If you or anyone will hear my situation, and offer possible solutions or
> advice,
> I would much appreciate the help.
> 
> My next assignment is a patch that was made to chan_sip some years
> back, that overcomes a problem with older aastra phones that are set up
> to
> turn functions keys into blf lights.
> 
> Such a phone issues two registrations in quick succession. The first
> indicates
> a normal expire= time, and uses the correct CallerID. But the second
> expiration
> is presented with a different callerid, but the same sip device, and
> gives
> an
> expires=0, which causes the phone to immediately deregister.
> 

<snip>

> 
> I have been studying the code, and have determined that the module in
> res/res_pjsip_registrar would be proper spot to make the change, in the
> registrar_validate_contacts function. I have but one small problem,
> and that is, I need to access either the pjsip endpoint object, or the
> asterisk object, to retrieve the expire value from the contact header of
> the first
> REGISTER request.
> 
> It was easy in the chan_sip code: the peer held the expire value from the
> first
> request.
> 
> But in the pjsip world, I am not easily finding this value, which is the
> expires=x
> value from the first REGISTER request. Then in the second request, I hope
> to reject the errant registration based on the difference in contact
> names
> between
> the two requests, and the fact the second request has expire=0, etc.
> 
> Again, any help would be appreciated. Conversations like this could be
> valuable
> to developers needing to work on res_pjsip.

The contact and expires is not stored on an endpoint. It's stored in a
contact structure (which holds the details of the Contact header from
the REGISTER) which is associated with the AOR. In fact I'd expect the
code to work already with that Aastra specific usage. When
res_pjsip_registrar got the unregister it would look for the associated
contact to remove, but as there is none by the given Contact it
shouldn't remove any.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org