ソースコード例：Ethernetパケット送信

#include <netpacket/packet.h>
#include <netinet/ip.h>
#include <sys/ioctl.h>

#define	IP_ALEN	4
static char buff[sizeof(struct ether_header) + sizeof(struct arphdr) + (ETH_ALEN + IP_ALEN) * 2];

int main(int argc, char **argv) {
	struct ether_header	*ether;
	struct arphdr		*arp;
	struct ifreq		ifr;
	struct sockaddr_in	*s_in;
	struct sockaddr_in	addr;
	struct sockaddr_ll	sa;
	unsigned int		saddr;
	int			i, sock, size, len, ret;
	char			*smac, *dmac, *sip, *dip, mac[ETH_ALEN];

	if(argc != 3) {
		printf("Usage : %s dev IPaddress\n", argv[0]);
		return -1;
	}
	inet_pton(AF_INET, argv[2], &saddr);
	sock = socket(AF_INET, SOCK_DGRAM, 0);
	if(sock < 0) {
		printf("socket1 error\n");
		return -1;
	}
	strncpy(ifr.ifr_name, argv[1], IFNAMSIZ-1);
	ifr.ifr_addr.sa_family = AF_INET;
	ioctl(sock, SIOCGIFHWADDR, &ifr);
	memcpy(mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
	ioctl(sock, SIOCGIFADDR, &ifr);
	s_in = (struct sockaddr_in *)&ifr.ifr_addr;
	close(sock);

	ether = (struct ether_header *)&(buff[0]);
	arp = (struct arphdr *)(buff + sizeof(struct ether_header));
	smac = buff + sizeof(struct ether_header) + sizeof(struct arphdr);
	dmac = buff + sizeof(struct ether_header) + sizeof(struct arphdr) + ETH_ALEN + IP_ALEN;
	sip = buff + sizeof(struct ether_header) + sizeof(struct arphdr) + ETH_ALEN;
	dip = buff + sizeof(struct ether_header) + sizeof(struct arphdr) + ETH_ALEN + IP_ALEN + ETH_ALEN;
	size = sizeof(buff);

	memset(ether->ether_dhost, 0xff, ETH_ALEN);
	memcpy(ether->ether_shost, mac, ETH_ALEN);
	ether->ether_type = htons(ETHERTYPE_ARP);

	arp->ar_hrd = htons(ARPHRD_ETHER);
	arp->ar_pro = htons(ETHERTYPE_IP);
	arp->ar_hln = ETH_ALEN;
	arp->ar_pln = IP_ALEN;
	arp->ar_op = htons(ARPOP_REQUEST);
	memset(dmac, 0, ETH_ALEN);
	memcpy(smac, mac, ETH_ALEN);
	memcpy(sip, (char*)&(s_in->sin_addr.s_addr), IP_ALEN);
	memcpy(dip, (char*)&saddr, IP_ALEN);

	sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
	if(sock < 0) {
		printf("socket2 error\n");
		return -1;
	}
	memset(&ifr, 0, sizeof(struct ifreq));
	strcpy(ifr.ifr_name, argv[1]);
	ret = ioctl(sock, SIOCGIFINDEX, &ifr);
	if(ret < 0) printf("ioctl error\n");
 	memset(&sa, 0, sizeof(struct sockaddr_ll));
	sa.sll_family = AF_PACKET;
	sa.sll_halen = ETH_ALEN;
	sa.sll_ifindex = ifr.ifr_ifindex;

	len = sendto(sock, &buff, sizeof(buff), 0, (struct sockaddr *)&sa, sizeof(struct sockaddr_ll));
	if(len <= 0) {
		printf("sendto error\n");
	}

	close(sock);

	return 0;
}