if (!output_packet_len || memcmp(nc_ether, net_null_ethaddr, 6)) {
/* going to check for input packet */
net_set_udp_handler(nc_handler);
if (!output_packet_len || memcmp(nc_ether, net_null_ethaddr, 6)) {
/* going to check for input packet */
net_set_udp_handler(nc_handler);