INADDR_ALLHOSTS_GROUP
sin->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
sin->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
send_adv(ifp, htonl(INADDR_ALLHOSTS_GROUP),
allhosts_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
#define in_allhosts(x) ((x).s_addr == htonl(INADDR_ALLHOSTS_GROUP))
(h->ip_dst.s_addr == INADDR_ALLHOSTS_GROUP)) {