On Thu, 10 Dec 2020 at 14:09, Alex Balashov <abalashov@evaristesys.com> wrote:

if(has_body("application/sdp") && search("a=sendonly")) [1]

It's what comes to mind off the top of my head, anyway.

-- Alex

[1] https://www.kamailio.org/docs/modules/stable/modules/textops.html

On 12/9/20 7:43 PM, David Cunningham wrote:
> Hi Alex,
>
> Thank you for that. Do you offhand know of an easy way to test if the
> sendonly attribute is set? Presumably we can use
> sdp_remove_line_by_prefix() to remove it.,
>
>
> On Wed, 9 Dec 2020 at 20:52, Alex Balashov <abalashov@evaristesys.com
> <mailto:abalashov@evaristesys.com>> wrote:
>
> The salient quality of a reinvite is that has_totag() == true; it is
> handled in the loose_route() section of your config. You want to do the
> SDP manipulation in the part below that, where initial INVITEs are
> handled.
>
> On 12/9/20 2:47 AM, David Cunningham wrote:
> > Hi Daniel,
> >
> > Removing the sendonly from the INVITE SDP sounds like the most
> workable
> > solution in our case. We'd only want to do it for a new INVITE
> though,
> > not a re-INVITE in a situation where a call is put on hold. Would
> you be
> > able to give an example of such a configuration?
> >
> > Thanks very much for your help!
> >
> >
> > On Tue, 8 Dec 2020 at 21:56, Daniel-Constantin Mierla
> <miconda@gmail.com <mailto:miconda@gmail.com>
> > <mailto:miconda@gmail.com <mailto:miconda@gmail.com>>> wrote:
> >
> > Hello,
> >
> > if the endpoint is not behind a port forwarding nat/firewall
> (when
> > one can instruct the rtp relay to use signaling address), then
> > probably you can try to remove the sendonly from the INVITE SDP.
> > That will enable rtp from endpoint to doorbell, which may rise
> > additional concerns (e.g., privacy) if its is explicitly not
> wanted
> > to happen. But as Alex said in another response, the only way
> to get
> > it work is to make the endpoint behind nat to send a RTP packet.
> > Usually the doorbells I encountered so far were accepting
> incoming
> > traffic as well, to discuss/interact with the person ringing
> on it.
> >
> > Cheers,
> > Daniel
> >
> > On 08.12.20 05:01, David Cunningham wrote:
> >> Hello,
> >>
> >> We have a problem with a SIP doorbell device which sends
> media one
> >> way only, and NAT at the receiving device.
> >>
> >> When the doorbell button is pressed it makes a call to a
> >> configured destination. Since the doorbell only sends and
> doesn't
> >> receive it sends the INVITE with sendonly in the SDP, and the
> >> destination then replies with a 200 OK with recvonly in the SDP.
> >> The problem is that the destination is behind NAT, and its reply
> >> contains a private network IP in the SDP.
> >>
> >> Normally Asterisk when nat=yes works around that by
> adjusting the
> >> destination for RTP to be the address it actually receives audio
> >> from, however because this device is recvonly Asterisk never
> >> receives audio from it. This means Asterisk keeps trying to send
> >> the doorbell's RTP to the private network IP which of course
> >> fails, and the destination never gets the RTP from the doorbell.
> >>
> >> We haven't found a solution in Asterisk to this, so are now
> >> looking to Kamailio which acts as a load-balancing proxy in
> front
> >> of Asterisk for one. For example, maybe we could use
> >> fix_nated_sdp, but only on 200 OK's with recvonly.
> >>
> >> Has anyone else encountered this, and are there any recommended
> >> solutions?
> >>
> >> Thank you in advance!
> >>
> >> --
> >> David Cunningham, Voisonics Limited
> >> http://voisonics.com/ <http://voisonics.com/>
> <http://voisonics.com/ <http://voisonics.com/>>
> >> USA: +1 213 221 1092
> >> New Zealand: +64 (0)28 2558 3782
> >>
> >> _______________________________________________
> >> Kamailio (SER) - Users Mailing List
> >> sr-users@lists.kamailio.org
> <mailto:sr-users@lists.kamailio.org>
> <mailto:sr-users@lists.kamailio.org
> <mailto:sr-users@lists.kamailio.org>>
> >> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
> <https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users>
> <https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
> <https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users>>
> >
> > --
> > Daniel-Constantin Mierla --www.asipto.com
> <http://www.asipto.com> <http://www.asipto.com <http://www.asipto.com>>
> > www.twitter.com/miconda <http://www.twitter.com/miconda>
> <http://www.twitter.com/miconda <http://www.twitter.com/miconda>>
> --www.linkedin.com/in/miconda <http://www.linkedin.com/in/miconda>
> <http://www.linkedin.com/in/miconda
> <http://www.linkedin.com/in/miconda>>
> > Funding:https://www.paypal.me/dcmierla
> <https://www.paypal.me/dcmierla> <https://www.paypal.me/dcmierla
> <https://www.paypal.me/dcmierla>>
> >
> >
> >
> > --
> > David Cunningham, Voisonics Limited
> > http://voisonics.com/ <http://voisonics.com/>
> <http://voisonics.com/ <http://voisonics.com/>>
> > USA: +1 213 221 1092
> > New Zealand: +64 (0)28 2558 3782
> >
> > _______________________________________________
> > Kamailio (SER) - Users Mailing List
> > sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
> > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
> <https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users>
> >
>
> --
> Alex Balashov | Principal | Evariste Systems LLC
>
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> Web: http://www.evaristesys.com/ <http://www.evaristesys.com/>,
> http://www.csrpswitch.com/ <http://www.csrpswitch.com/>
>
> _______________________________________________
> Kamailio (SER) - Users Mailing List
> sr-users@lists.kamailio.org <mailto:sr-users@lists.kamailio.org>
> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
> <https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users>
>
>
>
> --
> David Cunningham, Voisonics Limited
> http://voisonics.com/ <http://voisonics.com/>
> USA: +1 213 221 1092
> New Zealand: +64 (0)28 2558 3782
>
> _______________________________________________
> Kamailio (SER) - Users Mailing List
> sr-users@lists.kamailio.org
> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>

--
Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/

_______________________________________________
Kamailio (SER) - Users Mailing List
sr-users@lists.kamailio.org
https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users