webrtc2sip is not sending 200 OK to SIP MESSAGE sender for a delivered SIP MESSAGE where both users are served by webrtc2sip gw supported by a SIP server in the back-end

[GoogleCodeExporter]

What steps will reproduce the problem?
1. set-up - 2 sipml clients <--> webrtc2sip <--> sip server (freeswitch)
2. send an IM from 1002 to 1003 after registration

What is the expected output? What do you see instead?
1. 1003 user should receive the message only once and webrtc2sip should send 
200 OK to sip (at least after it receives 200 OK from sipml ua of 1003
2. as 200 OK in leg B is not sent from webrtc2sip to sip server (fs), the 
message is sent multiple times by sip server to 1003.

What version of the product are you using? On what operating system?
1. webrtc2sip - 2.6.0
2. freeswitch - 1.2.17 stable as of 24th Jan 2014 on git
3. sipml client on chrome - 32.0.1700.76 m
4. im code written as suggested in the sipml5.org web site

Please provide server logs with DEBUG level equal to INFO
1. webrtc2sip log and pcap attached
2. fs log and pcap attached

Please provide browser logs
1. chrome console logs for 1002 and 1002 user sipml agents attached
2. code snippets for im employed attached (call.htm and mvc-im-lib.js)

Original issue reported on code.google.com by vmelache...@gmail.com on 24 Jan 2014 at 6:34

Attachments:

• varuna-webrtcgw.log
• varuna-webrtcgw.pcap
• freeswitch.pcap
• freeswitch.log
• 1002-sipml-console.txt
• 1003-sipml-console.txt
• call.htm
• mvc-im-lib.js

[GoogleCodeExporter]

All,
Please be informed that the copyright headers in some of these poc code files 
are not complete and will be updated completely honoring the BSD terms once the 
code is ready for alpha distribution.

Original comment by vmelache...@gmail.com on 24 Jan 2014 at 6:40

[GoogleCodeExporter]

Forgot to mention in original issue - both webrtcgw and sip server are running 
on centos 6.5 x64

Original comment by vmelache...@gmail.com on 24 Jan 2014 at 6:48

[GoogleCodeExporter]

I just got to know about a similar issue/thread - 
https://groups.google.com/forum/#!searchin/doubango/200$20OK$20Message/doubango/
0SgoS-Olz_s/_JrF2c3yv-oJ. 

However, section 7 of SIP IM extension RFC 3428 says:
"A UAS receiving a MESSAGE request SHOULD respond with a final response 
immediately.  Note, however, that the UAS is not obliged to display the message 
to the user either before or after responding with a 200 OK.  That is, a 200 OK 
response does not necessarily mean the user has read the message."

"A UAS which is, in fact, a message relay, storing the message and forwarding 
it later on, or forwarding it into a non-SIP domain, SHOULD return a 202 
(Accepted) [5] response indicating that the message was accepted, but end to 
end delivery has not been guaranteed."

For the reported scenario, one can deduce from this RFC that a 200 OK is due 
from webrtc2sip which can not be found to be sent from the PCAP.

Original comment by vmelache...@gmail.com on 24 Jan 2014 at 7:00