[asterisk-bugs] [Asterisk 0017506]: MSG_OOB flag on HANGUP packet misused

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=17506 
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Reported By:                brycebaril
Assigned To:                
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Project:                    Asterisk
Issue ID:                   17506
Category:                   Resources/res_agi
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
Asterisk Version:           Older 1.6.2 - please test a newer version 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-06-14 15:51 CDT
Last Modified:              2010-06-15 11:04 CDT
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Summary:                    MSG_OOB flag on HANGUP packet misused
Description: 
When using fast AGI and the AGISIGHUP flag is enabled, Asterisk sends an
Out-of-Band "HANGUP\n" packet when the channel is terminated.  It uses the
MSG_OOB flag to send it URG/Out-of-Band via TCP.

This TCP feature is generally not used and not reliable (e.g.
http://en.wikipedia.org/wiki/Transmission_Control_Protocol#Out_of_band_data
) and in this case will cause only the "\n" character to be sent OOB.  The
"HANGUP" is still sent in-band, and can cause buffering issues --
especially with the "\n" being sent in a different band.  

Even if the developer sets socket options to get the OOB data in-band, the
"\n" will come in prior to the "HANGUP" because it is a higher priority.

I suggest dropping the "MSG_OOB" flag from this packet, as it doesn't seem
to do any good, and possibly only does harm.
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 (0123419) brycebaril (reporter) - 2010-06-15 11:04
 https://issues.asterisk.org/view.php?id=17506#c123419 
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This is not my observation.

When I read the data off the socket I see exactly 6 bytes, and they are
"HANGUP"

If I alter my socket like so:
setsockopt($agi_socket, SOL_SOCKET, SO_OOBINLINE, 1);

I receive a new message on the socket, 1 byte: "\n"

The next message on the socket is: 6 bytes "HANGUP"

So far I have been unable to get SIGURG to be triggered by this message. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-06-15 11:04 brycebaril     Note Added: 0123419                          
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