send_arp
static int send_arp = -1;
if (send_arp == -1) {
send_arp = 1;
if (send_arp == 1) {
send_arp = 0;
else if (send_arp == 0) {
send_arp = 1;
send_arp(tx, ARPOP_REQUEST, myip, mymac,
send_arp(tx, ARPOP_REQUEST, myip, mymac,