[Kamailio-Users] Path and received parameter

[Iñaki Baz Castillo]

El Martes 07 Abril 2009, Klaus Darilion escribió:
> > Alice              OBP              Proxy/Registrar                Bob
> >
> > ----- REGISTER --->  ---- REGISTER + Path -->
> >
> >                                                <----- INVITE --------
> > <---- INVITE ------  <----- INVITE + Route --
>
>                     ^^^^^^
> Here at this point the OBP forwards the request to Alice based on the
> RURI. The RURI is the URI which Alice provided in the Contact header of
> the REGISTER.

I understand your point.
BTW, couldn't the OBP change the REGISTER Contact address?
This is:

Alice     NAT      OBP              Proxy/Registrar                Bob

----(1) REGISTER ->  --(2)- REGISTER + Path -->

                                               <----- INVITE --------
<---(4)- INVITE ---  <--(3)- INVITE + Route ---


(1)
  REGISTER sip:...
  Contact: <sip:alice at ALICE_PRIVATE_IP>


(2)
  REGISTER sip:...
  Contact: <sip:alice at ALICE_PUBLIC_IP>
  Path: <sip:OBP>

(3)
  INVITE sip:alice at ALICE_PUBLIC_IP
  Route: <sip:OBP>

(4)
  INVITE sip:alice at ALICE_PUBLIC_IP



> Thus, there is the option to add the received parameter to the Path
> header. Then the OBP can derive the public IP:port from the received
> paramter in the Route header.

Yes, that would be the most ellegant solution since it would allow the OBP 
setting the destination URI:

  $du = "sip:ALIC_PUBLIC_IP"

and creating an INVITE as follows:

  INVITE sip:alice at ALICE_PRIVATE_IP


In this way, Alice would receive an INVITE with RURI matching *exactly* the 
Contact she used during registration.


> The question now is: Do I have to manually parse the route header,
> extract the received parameter and set $du, or is there somewhere a
> function which does this all?

Good question! :)
However, I expect you can use the string transformations to parse it.


Interesting subject :)



-- 
Iñaki Baz Castillo <ibc at aliax.net>