[pjsip] How to hangup a call - the right way ??

Benny Prijono bennylp at pjsip.org
Wed May 21 07:21:19 EDT 2008


On Wed, May 21, 2008 at 6:20 AM, Turnaev Eugeny <turnaev at t72.ru> wrote:
> Hello.  I wrote a simple app using python and pjsua.
>
> Which way one must hangup a call?
> Do i have to wait after " status = py_pjsua.call_hangup(call_id, 0, None, None) " call
> until callback on_call_state return that call is in py_pjsua.PJSIP_INV_STATE_DISCONNECTED state ?
>

Probably, depends on how the application is written. All (SIP) call
processings in pjsip are normally asynchronous, that is you start an
operation and get notification later (e.g. make_call(), call_hangup(),
etc.). So if you want a synchronous behavior somehow you'll have to
implement the wait operation in the application.


> I have a debug listing of my app where call to
>    status = py_pjsua.call_hangup(call_id, 0, None, None)
> returned status => 0 but a call still alive and in active state.
>
> In my app right after   py_pjsua.call_hangup(...), approx 100 lines of python code later
> app start a new call with call_make_call without waiting a callback to return that previous
> call is disconnected. From time to time it happens that call_hangup returns 0 but a call keeps
> living in active state .. state text EARLY.. and total duration increments. i can send my app log if it needed.
>

There's no guarantee that call_hangup() will trigger DISCONNECTED
callback to be called immediately. In the worst case, you'll get the
callback up to 32 seconds after call_hangup(), if remote is not
responding. In this case, the call duration will be kept incremented
of course.

> For now i am just checking all calls and if call in state EARLY and total duration > 50
> i am trying to hang up it again.
>
> So how do i work it around?
> ( If i have to wait for to call which i hangup with  status = py_pjsua.call_hangup and status => 0,
>  i am afraid of getting stucked in waiting forever for some buggy call to disconnect,
>  otherwise if not waiting i will end up with no free calls in pool,
>  so i am now not waiting but trying to clean buggy calls, is there a better solution?)
>

Please see above.

> By the way, even in cleaner function py_pjsua.call_hangup returned 0 for about a 5 times and
> total call duration before actual disconnect callback happened is 84 seconds while first hangup_call
> was at total duration 50 seconds.
>
> ---------------------------------------------------------------------
>
> And also i have an annoying
>         pjsua_call.c Timed-out trying to acquire PJSUA mutex (possibly system has deadlocked) in pjsua_call_get_info()
> in pjsua log.
> What does this mean? Two threads entered pjsua_call_get_info simultaneously?
> Looking at the time i suspected it happens when i am calling and call is not yet confirmed.
> I am have on_call_state callback (where a call to ci = py_pjsua.call_get_info(call_id) is) and also
> i am polling pjsip from my app in while loop.. ( also ci = py_pjsua.call_get_info(call_id) )..
> but i did set up Semaphore object and every call to py_pjsua.call_get_info protected with .acquire()
> in blocking mode.
>         (in fact the whole on_call_state callback def is inside .acquire() .release() ... and the whole snip that is polling
>         with ci = py_pjsua.call_get_info(call_id) is in .acquire() .release() ( as long as ci is used )  )
>
>         What other calls to py_pjsua i must take as critical area?
>

This has been discussed few times before, please see
http://www.google.com/custom?q=Timed-out+trying+to+acquire+PJSUA&domains=pjsip.org&sitesearch=pjsip.org

Unfortunately we lost the list archive when we moved the mailing list
late last year, but you can still get it from Google cache.

Cheers
 Benny




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