[asterisk-dev] ToDo for chan_skinny
Dan_Austin at Phoenix.com
Fri Jun 1 09:20:37 MST 2007
> Simon Lockhart wrote:
>> I'm fairly certain that chan_skinny already replies
>> to Keepalive messages from the phone (otherwise it
>> wouldn't work at all).
>> Th problem is that if the phone stops sending keepalives
>> (i.e. it goes away), then chan_skinny doesn't notice and
>> still tries sending calls to the now non-existent phone.
> My bad, it does too. Funny thing, it is one of the
> things that calls do_housekeeping, the others being
> hangups. So I guess you can't reliably use
> do_housekeeping to check if keepalives have been
> received as it relies on receiving keepalives for
> do_housekeeping to be called.
All true. The phone sends the keep-alive. Chan_skinny
responds. It looked like it should go in do_housekeeping,
but that won't work as it is not called unless it receives
But I believe I did find the issue. In get_input() the
code was using poll() with timeouts disabled. Code to check
for a dropped connection looked for a timeout, it was also
in a section of code that was unlikely to be reached but
IF the phone dropped while sending a request, the current
code would detect it and de-register the device.
My fix was to add a timeout to the poll() call based on
the configured keep_alive value +10% to handle network
congestion, and to move the code that tested for timeouts
into a code path that would regularly be reached.
Light testing has been positive (I have one 7940 and one
7920). Both have stayed registered overnight since I
implemented the patch, and unplugging the network from the
7940 has it being de-registered in less than the 30 second
keep_alive I used for testing.
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