bug: DHCPv6 does not respect prefix assigned to interface (<=/64)

[xvzf]

When odhcpd hands out IPv6 leases on an interface with a prefix <=/64 (e.g. /96), leases can (and often are) outside of the allocated /96 on the interface. I've looked a bit at the code and it seems the host_id calculation always infers 64bit, thus a /64 prefix. I would've expected odhcpd in DHCPv6 server mode, to actually respect the assigned prefix.

Are you open PR to fix this?