[asterisk-dev] [Code Review] chan_sip: Make the session-timers 'require: timer' header an option

[Darren Sessions]

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https://reviewboard.asterisk.org/r/698/
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Review request for Asterisk Developers.


Summary
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I've had several issues with the 'Require: timer' header option with regards to the session timers where vendors (primarily BT) and customers SBCs do not support this header and they reject calls as being formatted improperly.

Simply commenting this code out in chan_sip.c in the past has resolved the problem, however, I'm interested in a possibly more permanent solution. From what I can gather, this field is optional anyways (someone correct me if I'm wrong here). I've included an excerpt from RFC4028 (section 8.1) which seems to say that it's even not recommended.

Either way, this patch defaults the require timers option to true so as to be consistent with the existing default behavior. I've also included changes to the configs/sip.conf.sample.


>From RFC4028:

   The proxy MUST remember, for the duration of the transaction, whether
   the request contained the Supported header field with the value
   'timer'.  If the request did not contain a Supported header field
   with the value 'timer', the proxy *MAY* insert a Require header field
   with the value 'timer' into the request.  However, this is *NOT
   RECOMMENDED*.  This allows the proxy to insist on a session timer for
   the session.  This header field is not needed if a Supported header
   field was in the request; in this case, the proxy would already be
   sure the session timer can be used for the session.


Diffs
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  /trunk/channels/chan_sip.c 269269 

Diff: https://reviewboard.asterisk.org/r/698/diff


Testing
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Compile


Thanks,

Darren