[asterisk-dev] [Code Review] 3485: pjsip: Fix a bug where transferring to a parking extension causes calls to hang

[Jonathan Rose]

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This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/3485/
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(Updated May 21, 2014, 11:29 a.m.)


Review request for Asterisk Developers, Matt Jordan and Mark Michelson.


Changes
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Address jcolp + mjordan's findings.

I want to go ahead and point out that I found there are some conditions during blind transfers that will lead to the refer_progress_bridge stasis subscription never getting unsubscribed (bad, especially since it's holding on to references to other things). This is a pre-existing problem... happens with or without the patch in place. Basically any transfer that doesn't put the recipient in a bridge will cause this (transfers to IVRs for instance). One possible fix might be to track the subscription on a channel datastore for the transferer. I have a work around in place for parking so that it doesn't leak the subscription, but this is a problem that should probably be fixed at some point.


Repository: Asterisk


Description
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If a PJSIP endpoint attempts to blind transfer to a parking extension, there is an override to the normal transfer logic that can make things act a little weird. We noticed that this would leave various phones hanging on transfer screens without progressing. When the transfer was considered successful, PJSIP deferred the actual action of sending the 200 notify and the actual trigger for that happening never occurs when the transfer is to a parking extension.

In order to handle this, the bridge function that handles blind transfers now returns a different value if a call was parked and if the channel driver needs to react differently in this case, it can.  In the case of PJSIP, we respond to transfers to park by immediately sending the notify with 200 OK sip frag instead of deferring the action.


Diffs (updated)
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  /branches/12/res/res_pjsip_refer.c 413303 
  /branches/12/res/parking/parking_bridge_features.c 413303 
  /branches/12/res/parking/parking_applications.c 413303 
  /branches/12/main/parking.c 413303 
  /branches/12/main/bridge_basic.c 413303 
  /branches/12/main/bridge.c 413303 
  /branches/12/include/asterisk/parking.h 413303 
  /branches/12/include/asterisk/bridge.h 413303 
  /branches/12/channels/sig_analog.c 413303 
  /branches/12/channels/chan_sip.c 413303 
  /branches/12/channels/chan_mgcp.c 413303 
  /branches/12/channels/chan_dahdi.c 413303 

Diff: https://reviewboard.asterisk.org/r/3485/diff/


Testing
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Before patch:
* Blind transfer on Polycom SPIP: Phone is on the blind transfer screen until it either manually hangs up or 60 seconds pass and Asterisk terminates the session.

After the patch:
* Blind transfer on Polycom SPIP: Phone immediately leaves the blind transfer screen and goes back to idle mode.


Thanks,

Jonathan Rose

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