in6_get_stableifid
if ((ifp0->if_inet6->nd_flags & ND6_IFF_STABLEADDR) && in6_get_stableifid(ifp0, in6, 64) == 0) {
bool in6_get_stableifid(struct ifnet *, struct in6_addr *, int);
if(!in6_get_stableifid(ifp, &newaddr, prefixlen))