[sr-dev] Possible bug in RLS module

[Peter Dunkley]

Hi Daniel,

This SUBSCRIBE is a back-end SUBSCRIBE generated by RLS and directed to
PRESENCE.

The RLS module sends that SUBSCRIBE and gets a 202 back from PRESENCE.
The PRESENCE module is then sending that NOTIFY back to the RLS module
after the unSUBSCRIBE is complete.

So:
- Either the PRESENCE module should not send this NOTIFY to the RLS
after the unSUBSCRIBE, or
- The RLS module should be prepared to receive a NOTIFY from PRESENCE
after the unSUBSCRIBE

Thanks,

Peter

On Thu, 2011-04-07 at 11:34 +0200, Daniel-Constantin Mierla wrote:

> Hi Peter,
> 
> On 4/4/11 3:39 PM, Peter Dunkley wrote: 
> 
> > Hello Daniel,
> > 
> > I have looked into the new error message.  I now get:
> > 
> >     7(21352) ERROR: rls [resource_notify.c:250]: record not found
> > 
> > This looks very similar to the previous issue.  What appears to be
> > happening is that the RLS is successfully un-subscribing from the
> > presence module with a SUBSCRIBE that looks like:
> > 
> > 
> >         SUBSCRIBE sip:alice at crocodile-rcs.com SIP/2.0
> >         Via: SIP/2.0/UDP
> >         46.38.172.248;branch=z9hG4bKf89b.b9ec2180000000000000000000000000.0
> >         To: sip:alice at crocodile-rcs.com
> >         From:
> >         sip:bob at crocodile-rcs.com;tag=533cb9e91f4b999cf76861cbb9ed54ed-8c1c
> >         CSeq: 10 SUBSCRIBE
> >         Call-ID: 6c60e3f8-21440 at 127.0.0.1
> >         Content-Length: 0
> >         User-Agent: Crocodile SuperNode 1.1
> >         Max-Forwards: 70
> >         Event: presence
> >         Contact: <sip:rls at 46.38.172.248:5060>
> >         Expires: 0
> >         Supported: eventlist
> >         Accept: application/pidf+xml, application/rlmi+xml,
> >         application/watcherinfo+xml, multipart/related
> > 
> > 
> > After accepting (with 202) this SUBSCRIBE the presence module tries
> > to send a NOTIFY back to the RLS module:
> > 
> > 
> >         NOTIFY sip:rls at 46.38.172.248:5060 SIP/2.0
> >         Via: SIP/2.0/UDP
> >         127.0.0.1;branch=z9hG4bK7a28.7240a060000000000000000000000000.0
> >         To:
> >         sip:bob at crocodile-rcs.com;tag=533cb9e91f4b999cf76861cbb9ed54ed-8c1c
> >         From:
> >         sip:alice at crocodile-rcs.com;tag=a6a1c5f60faecf035a1ae5b6e96e979a-5cd7
> >         CSeq: 1 NOTIFY
> >         Call-ID: 6c60e3f8-21440 at 127.0.0.1
> >         Content-Length: 0
> >         User-Agent: Crocodile SuperNode 1.1
> >         Max-Forwards: 70
> >         Event: presence
> >         Contact: <sip:127.0.0.1:5060;transport=udp>
> >         Subscription-State: terminated;reason=timeout
> > 
> > This NOTIFY is passed into the RLS module using rls_handle_notify()
> > and the error message from above appears in the log file.  There is
> > no final response sent to the NOTIFY so the error message appears
> > repeatedly for 32 seconds until the presence module times out.
> > 
> > I think there are two issues here: 
> >       * After completing the unSUBSCRIBE the RLS module removes the
> >         dialog from the hash table.  This means that the NOTIFY from
> >         presence doesn't match a dialog - hence the error message. 
> 
> is this SBSCRIBE request handled by RLS module, not by presence (ie,
> it is for a resource list or for an user)?
> 
> 
> >       * rls_handle_notify() does not send an Fxx (or at least does
> >         not in this case) when it receives a validly formed NOTIFY
> >         that still causes an error. 
> > 
> > Can you suggest a work-around?
> 
> rls_handle_notify() sends 200ok only when returning true to config. In
> this case, since it hasn't found the proper dialog, will return false.
> 
> Try:
> 
> if(!rls_handle_notify()) {
>    send_reply("404", "Not found");
>   exit;
> }
> 
> Perhaps will be nicer to differentiate between the cases of internal
> error, whether it is some server fault (e.g., out of memory, broken db
> connection) or the dialog is not found, to be able to send back either
> 500 or 404.
> 
> Cheers,
> Daniel
> -- 
> 
> Daniel-Constantin Mierla
> http://www.asipto.com


-- 
Peter Dunkley
Technical Director
Crocodile RCS Ltd
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