[OpenSER-Devel] [ openser-Bugs-1818469 ] 200 for CANCEL contains wrong To_tag

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Bugs item #1818469, was opened at 2007-10-23 12:26
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Category: core
Group: ver 1.2.x
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Iñaki Baz (ibc_sf)
Assigned to: Nobody/Anonymous (nobody)
Summary: 200 for CANCEL contains wrong To_tag

Initial Comment:
According to RFC 3261 "9.2 Server Behavior":

  "...the UAS answers the CANCEL request itself with
   a 200 (OK) response.  This response is constructed
   following the procedures described in Section
   8.2.6 noting that the *To tag* of the response to
   the CANCEL and the *To tag* in the response to the
   original request SHOULD be the *same*.  The
   response to CANCEL is passed to the server 
   transaction for transmission."

But OpenSer doesn't not it. OpenSer generates a new To tag for the 200 to the CANCEL different from the To tag received in the 180 Ringing.

I attach a trace in which Asterisk calls to a OpenSer user, this user rings but Asterisk sends a CANCEL. The 200 To_tag to this CANCEL is different of the To_tag in the 180:


# Phone -> OpenSer
SIP/2.0 180 Ringing 
Via: SIP/2.0/UDP 85.12.12.110;branch=z9hG4bK2bca.08cf2485.0
Via: SIP/2.0/UDP 85.12.12.111:5060;rport=5060;branch=z9hG4bK57feb524
To: <sip:ibc at sip.domain.org>;tag=bptnj
...

# OpenSer -> Asterisk
SIP/2.0 180 Ringing 
Via: SIP/2.0/UDP 85.12.12.111:5060;rport=5060;branch=z9hG4bK57feb524
To: <sip:ibc at sip.domain.org>;tag=bptnj

# Asterisk -> OpenSer
CANCEL sip:ibc at sip.domain.org SIP/2.0
Via: SIP/2.0/UDP 85.12.12.111:5060;branch=z9hG4bK57feb524;rport
From: "asterisk" <sip:asterisk at sip.domain.org>;tag=as2bf71219
To: <sip:ibc at sip.domain.org>

# Openser -> Asterisk
SIP/2.0 200 canceling 
Via: SIP/2.0/UDP 85.12.12.111:5060;branch=z9hG4bK57feb524;rport=5060
From: "asterisk" <sip:asterisk at sip.domain.org>;tag=as2bf71219
To: <sip:ibc at sip.domain.org>;tag=fa997f81440371de71ab448ebdb9af56-31d7
Call-ID: 7494f28219c


Because it Asterisk resends CANCEL again and again.

I've seen most devices "allow" it, but IMHO it's not RFC compliant, is it?

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