Recursive nexthop via kernel route in proto static not working

[Daniel Gröber]

Hi,

I'm trying to configure a static route that uses the system's default
router. The default router is out of my control and is announced via IPv6
RA. Since the MAC might not be stable I'd prefer not to hardcode the
router's link-local address. So I tried:

    protocol static static_export_kernel2 {
        ipv6;
        igp table master6;
        route 2001:db8::/48 recursive ::;
    }

The thinking being that :: ought to be resolvable through the default route
imported from proto kernel:

    birdc show route for :: all
    Table master6:
    ::/0                 unicast [kernel1 2023-03-22] * (10)
            via fe80::fc00:3ff:fec7:cd05 on enp1s0
            Type: inherit univ
            Kernel.source: 9
            Kernel.metric: 1024
            Kernel.hoplimit: 64

However the static route ends up being "unreachable":

    2a0d:f302:114::/48   unreachable [static_export_kernel2 13:59:32.819] * (200)
            Type: static univ

Any ideas why this isn't working?

Thanks,
--Daniel

PS: The reason I have to create this static route when it's already covered
by the default route has to do with an esoteric policy routing setup and
multiple routing daemons ask for details at your own peril :)