I have an UPnP server on the internal network, i.e. it sends out multicast messages for SSDP (220.127.116.11). igmpproxy forwards them to the upstream interface. If I use the new "whitelist" keyword on the downstream interface then this doesn't happen, but that means that the UPnP server won't be visible on the other downstream interfaces.
The attached patch utilizes the "whitelist" keyword also on the upstream interface. I wasn't sure how to implement this correctly. I choose the solution of blocking upstream Join/Leave messages for non-whitelisted multicast groups. It seems to work OK in my setup.
If this patch is OK for you I can try a "git push" as I have a SF account and should(?) have git write access.
Date: Fri Dec 11 21:08:57 2009 +0200
Restrict igmp reports forwarding to upstream interface
Utilize the new "whitelist" keyword also on the upstream interface definition.
If specified then only whitelisted multicast groups will be forwarded upstream.
This can be used to avoid publishing private multicast groups to the world,
e.g. SSDP from a UPnP server on the internal network.