[OpenSIPS-Users] packet forwarding when two mediaproxy 2.0s are back-to-back

[Alex Hermann]

On Friday 05 September 2008, you wrote:
> Alex Hermann writes:
>  > Shouldn't the mediaproxy just start forwarding to the addresses/ports in
>  > the SDP and update the destinations when the learned source address/port
>  > is different? Instead of trying to learn both endpoints before
>  > forwarding any traffic.
>
> that kind of strategy sounds good to me.  i don't know though, if
> mediaproxy 2.0 implementation can support (without update by control
> protocol) such dynamic change of packet destination once the flow has
> started.

It should be possible to signal/send packets arriving from a different source 
IP and/or port via a netlink socket to userspace. The same (or similar) 
technique is used to implement netfilter rules in userspace.

Alternatively, if the proxy knows a-priori that one party's SDP addresses are 
to be trusted, a flag like nathelper's "r" flag [1] might be a possibility. 
(When using use_media_proxy, not engage_media_proxy as the latter doesn't 
provide a way to 'manually' update a reply SDP)

[1] http://www.opensips.org/html/nathelper.html#id2520259

-- 
Greetings,

Alex Hermann