[OpenSER-Users] Changing From: and To: URIs...

Phil D'Amore ptdamore at gmail.com
Thu Nov 29 19:42:34 CET 2007


Sorry, this reply didn't originally go to the whole list...

I was talking about the to tag only in the context of modifying the
UAC module to do this like it does From.  I realize now that it's only
the URI being modified so you're right, the tags don't matter.

My original concern with just re-writing the To: URI is that, strictly
speaking, it's not allowed by RFC3261.  Specifically section 12.2.1.1,
which requires reflection of the original To: and From: URIs in
subsequent requests in a dialog.  If a UA sends a re-invite back
upstream, it will reflect my re-written URI to the original UA, which
then might not be able to match the dialog because the URI is
different.

I believe that is why uac_replace_from exists for the From header.
The uac module catches such requests, and restores the original URI.
I know of nothing that currently handles To that way.

In reality, UAs fully supporting 3261 shouldn't care about the URI,
and the restriction I mentioned above is only for backward
compatability.  Perhaps I'm worrying about nothing, but
uac_replace_from must exist for a reason.

Thanks,
Phil

On Nov 29, 2007 12:51 PM, Alex Balashov <abalashov at evaristesys.com> wrote:
>
> Phil,
>
> Why would you have to deal with the To tag?
>
> I've had to do this very often and simply using textops to transform the
> headers precisely as you describe has always worked.  Just use regex
> to conserve all the tags and other extended fields that appear in the
> To and From URIs.
>
> -- Alex
>
>
> On Thu, 29 Nov 2007, Phil D'Amore wrote:
>
> > Hi Everyone...
> >
> > I'm looking for some advice.  Let's say I have a To: header in an
> > initial INVITE:
> >
> > To: Bob <sip:8005551212 at sip.example.com>
> >
> > Due to carrier requirements, it really needs to be:
> >
> > To: Bob <sip:+18005551212 at sip.example.com>
> >
> > I'm not asking how to do it.  I know I can use some textops functions
> > to make this happen.  I also know that doing this might break
> > something.
> >
> > The uac module already nicely handles the From: header in a way that
> > doesn't break things.  I thought about extending this to handle To:,
> > but I worried that the Record-Route header might get too long for some
> > UAs if I wind up having to change both headers.  The To tag must also
> > be dealt with somehow, which I think might make it harder to do than
> > From.
> >
> > Using a 302 response is not an option for me, and I'm really trying to
> > avoid getting a B2BUA involved with this right now.  Moving from
> > openser 1.1.1 to 1.3 is enough for me without changing my architecture
> > ;).  I'm wondering what would be the best way given what openser can
> > do right now (1.3) to re-write that header that doesn't break
> > anything.  I'm not adverse to writing some code to make it happen if
> > that is what is needed.
> >
> > Any ideas?
> >
> > Thanks,
> > Phil
> >
> > _______________________________________________
> > Users mailing list
> > Users at lists.openser.org
> > http://lists.openser.org/cgi-bin/mailman/listinfo/users
> >
>
> --
> Alex Balashov
> Evariste Systems
> Web    : http://www.evaristesys.com/
> Tel    : +1-678-954-0670
> Direct : +1-678-954-0671
>




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