nd6_output_ifp
error = nd6_output_ifp(nh->nh_ifp, origifp, m, &dst, NULL);
error = nd6_output_ifp(ifp, origifp, m, dst, (struct route *)ro);
error = nd6_output_ifp(ifp, ifp, m, &dst6, (struct route *)&ro);
int nd6_output_ifp(struct ifnet *, struct ifnet *, struct mbuf *,
ret = nd6_output_ifp(ifp, ifp, md, &dst, NULL);
nd6_output_ifp(rt, rt, m, &dst, NULL);