issue with static address and IPv6 PD

[madires]

Hi!

While setting up IPv6 PD with OpenWRT 18.06.4 I found several issues. This one is about bad route entries when the IPv6 assignment length and a static IPv6 address are configured for an interface. In this case the LAN's IPv6 assignment length is set to /62 and a static ULA address is configured. When a downstream router on the LAN sends two IA_PD requests, one for a /63 and another for /64, odhcpd will assign the prefixes and add route entries:
2003:a:b:c01::/64 via fe80::a:b:c:d dev br-lan metric 1024
2003:a:b:c02::/63 via fe80::a:b:c:d dev br-lan metric 1024

But it also adds following routes:
fd00:d:e:f::/64 via fe80::a:b:c:d dev br-lan metric 1024
fd00:d:e:f::/63 via fe80::a:b:c:d dev br-lan metric 1024

The static ULA address is:
inet6 fd00:d:e:f::1/64 scope global

Cheers,
Markus