in6_are_prefix_equal
int in6_are_prefix_equal(struct in6_addr *, struct in6_addr *, int);
in6_are_prefix_equal(&key->ndpr_prefix.sin6_addr,
in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,