[Sip] Re: URI comparison rules - IPv6 addresses

[Gonzalo Camarillo <[e-mail]>]

Hi Vijay,

if this document becomes a WG item, I agree it would be the perfect 
place to document this issue.

Cheers,

Gonzalo


Vijay K. Gurbani wrote:
> Gonzalo Camarillo wrote:
>> Hi,
>>
>> Brett brought this up in the SIP Implementors mailing list. The
>> following IPv6 addresses are supposed to be equivalent:
>>
>> [::ffff:192.0.2.128] and [::ffff:c000:280]
>> [2001:db8::9:1] and [2001:db8::9:01]
>> [0:0:0:0:0:FFFF:129.144.52.38] and [::FFFF:129.144.52.38]
>>
>> Now, let's say I need to compare sip:user1@[::ffff:192.0.2.128] and
>> sip:user1@[::ffff:c000:280]. Should we consider these URIs to be
>> equivalent or not?
>>
>> My proposal is that we clarify that IPv6 address comparison happens at
>> the binary level, not at the textual level. We could log a bug against
>> RFC3261, and try and add such a clarification to the IPv6 transition
>> document (I will need to ask the ADs whether or not we can add this in
>> AUTH48).
> 
> Gonzalo: My only concern that I had mentioned to Brett as
> well was that this should not be construed as endorsing the
> notion of multiple representations of the IPv6 address in
> SIP signaling.  This may cause problems in normal SIP operations.
> 
> Consider a proxy that uses the sent-by address in a loop detection
> mechanism.  If it gets a looped request but the upstream proxy
> had now put a different representation of the IP address, then
> the proxy will not recognize that as a loop.  Admittedly, the
> upstream proxy should not be inserting different representations
> of the same IP address in each request (unless, of course it is
> malicious; but then if it is malicious, it could probably do
> damage by other means.)
> 
> Now, regarding where to put it: in v6-transition or in a SIP
> essential fix, here are some thoughts.  Insofar as we are talking
> about URI comparison, this clarification is probably best put
> in S19.1.4 (URI Comparison) of rfc3261.  We already have a
> SIP essential fix document that fixes the IPv6 ABNF in rfc3261
> (http://tools.ietf.org/html/draft-gurbani-sip-ipv6-abnf-fix-00);
> this clarification could be tacked on in that draft if the WG
> agrees.  Thoughts?
> 
> Thanks,
> 
> - vijay



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