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

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
====================================================================== 
https://issues.asterisk.org/view.php?id=17506 
====================================================================== 
Reported By:                brycebaril
Assigned To:                
====================================================================== 
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:              
====================================================================== 
Date Submitted:             2010-06-14 15:51 CDT
Last Modified:              2010-06-15 15:57 CDT
====================================================================== 
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.
====================================================================== 

---------------------------------------------------------------------- 
 (0123450) brycebaril (reporter) - 2010-06-15 15:57
 https://issues.asterisk.org/view.php?id=17506#c123450 
---------------------------------------------------------------------- 
I am using Perl, which doesn't have any wrappers over setsockopt, or
anything else related to this protocol.  What I'm seeing matches the TCP
documentation I've found.

Its safe signal handling may be interfering with SIGURG, but that isn't
the ideal solution for my application. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2010-06-15 15:57 brycebaril     Note Added: 0123450                          
======================================================================