arplookup
la = arplookup(ifp, addr, sa, wlock);
ln = arplookup(ifp, NULL, rt_getkey(rt), 1);
la = arplookup(ifp, NULL, dst, 0);
la = arplookup(ifp, &isaddr, NULL, 1);
struct llentry *arplookup(struct ifnet *,
ln = arplookup(ifp, &nb_addr, NULL, 0);