at_ifawithnet
ifa = at_ifawithnet((const struct sockaddr_at *)addr,
ifa = at_ifawithnet((const struct sockaddr_at *)dst, ifp);
if ((aa = (struct at_ifaddr *) at_ifawithnet(sat, ifp)) == NULL) {
ifa = at_ifawithnet(destsat, ifp);
ifa = at_ifawithnet(&sat, ifp);
at_ifawithnet(const struct sockaddr_at *, struct ifnet *);