implement RFC 8781 (Discovering PREF64 in Router Advertisements)

[ghost]

Hi

RFC 8781 (https://www.rfc-editor.org/rfc/rfc8781.txt) is a nice way to get the plat-prefix direct by the router. So you don't need the dns64 server.

[toreanderson]

It is very unlikely that I would be able to implement this in clatd, because the receipt and parsing of ICMPv6 RAs are either done by the kernel or some user-space network management service like NetworkManager or systemd-networkd.

If they expose the prefix somewhere, like in sysfs or dbus, I guess it would be possible to look it up. I am not aware of any way to do it, though.

[ghost]

I'm currently writing a small C program to get the pref64 option. Would it be possible to include this with a plat-detector-script option (option name is just to have an example)?

[toreanderson]

Sure, I would be happy to include something like that!

[herbetom]

In systemd Version 255 a UsePREF64 option was added to networkd:

https://www.freedesktop.org/software/systemd/man/latest/systemd.network.html#UsePREF64=

Not sure if there are already tools taking advantage of it to have an implementation example.

To me it seems hoewer sensible to rely on the network configuration utilities to get that information.