[sr-dev] Possible bug in RLS module

[Daniel-Constantin Mierla]

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 <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 <mailto: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 <mailto: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

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