in6_ifawithscope
ia6 = in6_ifawithscope(rt->rt_ifa->ifa_ifp, &t, rtableid, rt);
struct in6_ifaddr *in6_ifawithscope(struct ifnet *, const struct in6_addr *,
ia6 = in6_ifawithscope(ifp, dst, rtableid, NULL);
ia6 = in6_ifawithscope(ifp, dst, rtableid, rt);
ia6 = in6_ifawithscope(ifp, dst, rtableid, NULL);
ia6 = in6_ifawithscope(ifp, dst, rtableid, NULL);