[asterisk-bugs] [Asterisk 0010289]: Old LAGRQ frames showing up in new IAX2 calls

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=10289 
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Reported By:                mihai
Assigned To:                russell
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Project:                    Asterisk
Issue ID:                   10289
Category:                   Channels/chan_iax2
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     assigned
Asterisk Version:           1.4.8  
SVN Branch (only for SVN checkouts, not tarball releases): N/A  
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             07-24-2007 10:52 CDT
Last Modified:              08-01-2007 14:38 CDT
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Summary:                    Old LAGRQ frames showing up in new IAX2 calls
Description: 
If there are two successive IAX2 calls having the same source and
destination call id, sometimes old LAGRQ frames belonging to the first call
are transmitted as part of a VNAK retransmission during the second call.
Since the old LAGRQ have wildly out of order sequence numbers, the other
endpoint will request retransmission, which can cause a VNAK storm.
I am able to reproduce this by stress testing chan_iax2 with an automated
script that generates about 3 calls per second, up to about 200
simultaneous calls.  This will pretty much guarantee that source ids will
be recycled on the server side, which can trigger this issue. 
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---------------------------------------------------------------------- 
 mihai - 08-01-07 14:38  
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Uploaded two patches that attempt to solve the problem.
The first one is just a first attempt, and has some issues.
The second one is better and more elegant. Here's what it does:
- add a flag to iax_thread that signals if the thread is ready to accept
conditions
- after creating the thread, wait in a spinloop for the flag to pop up
- in iax2_process_thread, set the flag after we lock our mutex

This way we ensure that by the time schedule_action gets its thread, the
thread will be ready 

Issue History 
Date Modified   Username       Field                    Change               
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08-01-07 14:38  mihai          Note Added: 0068237                          
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