[asterisk-dev] [Code Review] Avoid infinite loop with certain local channel connected line updates

[Russell Bryant]

> On 2010-09-20 19:33:20, rmudgett wrote:
> > /branches/1.8/main/channel.c, lines 8203-8206
> > <https://reviewboard.asterisk.org/r/932/diff/3/?file=12582#file12582line8203>
> >
> >     For this compare to work for all cases, you should also pass in update.  Update indicates what is intended to be changed.  The parts not specified by update are not going to be affected and may differ.
> >     
> >     Also, I note that the buffer is built twice for the passed in connected line.

Thanks, Richard!  Great catch.


- Russell


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On 2010-09-20 17:56:40, Terry Wilson wrote:
> 
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> https://reviewboard.asterisk.org/r/932/
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> 
> (Updated 2010-09-20 17:56:40)
> 
> 
> Review request for Asterisk Developers, Russell Bryant and Mark Michelson.
> 
> 
> Summary
> -------
> 
> It is possible to create an infinite loop with connected line updates and local channels. One side of the local channel queues an update to the other side in local_indicate() which then causes the other side to do the same ad infinitum. This patch adds a function to compare the connected line update with the connected line info already on a channel. If there is no difference, it doesn't send the update frame.
> 
> It uses ast_connected_line_build_data since that function would need to be changed if any of the ast_connected_line-related structs changed and trying to compare each setting individually is really a pain and would be just another function to update.
> 
> 
> Diffs
> -----
> 
>   /branches/1.8/main/channel.c 287638 
> 
> Diff: https://reviewboard.asterisk.org/r/932/diff
> 
> 
> Testing
> -------
> 
> queues.conf
> ---------
> [general]
> persistentmembers = yes
> autofill = yes
> monitor-type = MixMonitor
> shared_lastcall=no
> 
> [test]
> strategy=ringall
> member => Local/6001 at sip/nm
> reportholdtime=yes
> 
> extensions.conf
> -------------
> [sip]
> exten => 123,1,NoOp
> exten => 123,n,Answer
> exten => 123,n,Queue(test)
> 
> exten => _XXXX,1,Set(CONNECTEDLINE(num,i)=5551212)
> exten => _XXXX,n,Set(CONNECTEDLINE(name,i)=Widgets)
> exten => _XXXX,n,Set(__CONNECTED_LINE_CALLEE_SEND_MACRO=CONNECTED_LINE_MANIPULATION)
> exten => _XXXX,n,Set(__CONNECTED_LINE_CALLER_SEND_MACRO=CONNECTED_LINE_MANIPULATION)
> exten => _XXXX,n,Dial(SIP/${EXTEN})
> 
> [macro-CONNECTED_LINE_MANIPULATION]
> exten => s,1,NoOp(MACRO WAS CALLED)
> 
> sip.conf
> ------
> 
> [test](!)
> type=friend
> host=dynamic
> secret=whatever
> canreinvite=no
> context=sip
> callgroup=1
> pickupgroup=1
> 
> 
> [6001](test)
> [6002](test)
> 
> To reproduce
> -----------
> 6001 calls 100, puts on hold and dials *8 to pickup own call and transfers the the original call (in Eyebeam dials 100 on line 1, dials *8 on line two, hit XFER and click on line 1).
> 
> Before the patch, the macro is executed indefinitely. After, only once.
> 
> 
> Thanks,
> 
> Terry
> 
>