memset(&addr, 0, sizeof(addr));
strcpy(addr.sa_data, interface);
if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
rv = 0;
memset(&addr, 0, sizeof(addr));
strcpy(addr.sa_data, interface);
if (sendto(s, &arp, sizeof(arp), 0, &addr, sizeof(addr)) < 0)
rv = 0;