The IPv6 ntuple filter is unable to verify the destination IP address of the packet, so it's possible that Gatekeeper could receive a packet that is not destined for it. In that case, we should redirect the packet.

This has only been marked as a TODO for the GT-GK Unit (the back interface), since the front interface (the GK block) already forwards IPv6 traffic as needed.

This feature should remove the relevant TODO in ggu/main.c.