IPv6 support for DNS Security DNAT

[cdheiser]

Security scans incorrectly flag DNAT rules for IPv6 as having invalid addresses:

DNS: Invalid DNAT Translated IP
DNAT DNS rules have incorrect translated IP address.

[cdheiser]

Security analysis should also probably detect if IPv6 is in use and flag IPv6 variants as it seems IPv6 is just completely ignored.

[tvancott42]

Yes and no, it's all coded for, I just haven't had the opportunity to test it.

IPv6 uptake on UniFi networks is rather low in the wild still. None of my ISPs support it on my home test network so I really have no way to test any of the IPv6 considerations I have in code end-to-end.

If you're willing, I can work through this one thing at a time. It's possible DNAT rules didn't get my revised IPv6-aware CIDR/Network inclusion logic, among other places.

[tvancott42]

@cdheiser I got this worked out on a branch, but ultimately had to switch my home network back to IPv4 only as WAN load balancing w/ only one IPv6 WAN connection was hosing my clients pretty badly.

If you want to build from source, this branch may fix IPv6 support for DNAT at least: feature/ipv6-support

I'll be adding more IPv6 fixes there as I go, but I'll have to set up a single IPv6-enabled VLAN bound to my IPv6 WAN and stick my dev box on it over the next week.