memcpy(&req.in_pa.sin_addr, &buf.ip.saddr, sizeof(buf.ip.saddr));
req.arp.arp_ha.sa_family = AF_LOCAL;
memcpy(&req.arp.arp_ha.sa_data, &buf.eth.h_source, sizeof(buf.eth.h_source));
memcpy(&req.in_pa.sin_addr, &buf.ip.saddr, sizeof(buf.ip.saddr));
req.arp.arp_ha.sa_family = AF_LOCAL;
memcpy(&req.arp.arp_ha.sa_data, &buf.eth.h_source, sizeof(buf.eth.h_source));