strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name));
if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
fprintf(stderr, "%s: nonexistent interface '%s' specified\n",
strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name));
if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&ifr) < 0) {
fprintf(stderr, "%s: nonexistent interface '%s' specified\n",