SIOCGIFPARENT
if (ioctl(sock, SIOCGIFPARENT, (caddr_t)&ifp) == -1) {
case SIOCGIFPARENT:
case SIOCGIFPARENT:
case SIOCGIFPARENT:
case SIOCGIFPARENT:
case SIOCGIFPARENT:
case SIOCGIFPARENT: