#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<features.h>
#include<linux/if_packet.h>
#include<linux/if_ether.h>
#include<errno.h>
#include<sys/ioctl.h>
#include<net/if.h>
#include<net/ethernet.h>

#define SRC_ETHER_ADDR	"aa:aa:aa:aa:aa:aa"
#define DST_ETHER_ADDR	"bb:bb:bb:bb:bb:bb"


int CreateRawSocket(int protocol_to_sniff)
{
	int rawsock;

	if((rawsock = socket(PF_PACKET, SOCK_RAW, htons(protocol_to_sniff)))== -1)
	{
		perror("Error creating raw socket: ");
		exit(-1);
	}

	return rawsock;
}

int BindRawSocketToInterface(char *device, int rawsock, int protocol)
{
	
	struct sockaddr_ll sll;
	struct ifreq ifr;

	bzero(&sll, sizeof(sll));
	bzero(&ifr, sizeof(ifr));
	
	/* First Get the Interface Index  */


	strncpy((char *)ifr.ifr_name, device, IFNAMSIZ);
	if((ioctl(rawsock, SIOCGIFINDEX, &ifr)) == -1)
	{
		printf("Error getting Interface index !\n");
		exit(-1);
	}

	/* Bind our raw socket to this interface */

	sll.sll_family = AF_PACKET;
	sll.sll_ifindex = ifr.ifr_ifindex;
	sll.sll_protocol = htons(protocol); 


	if((bind(rawsock, (struct sockaddr *)&sll, sizeof(sll)))== -1)
	{
		perror("Error binding raw socket to interface\n");
		exit(-1);
	}

	return 1;
	
}


int SendRawPacket(int rawsock, unsigned char *pkt, int pkt_len)
{
	int sent= 0;
	printf("Packet len: %d\n", pkt_len);
	/* A simple write on the socket ..thats all it takes ! */

	if((sent = write(rawsock, pkt, pkt_len)) != pkt_len)
	{
		/* Error */
		printf("Could only send %d bytes of packet of length %d\n", sent, pkt_len);
		return 0;
	}

	return 1;
	

}

unsigned char* CreateEthernetHeader(char *src_mac, char *dst_mac, int protocol)
{
	struct ethhdr *ethernet_header;

	
	ethernet_header = (struct ethhdr *)malloc(sizeof(struct ethhdr));

	/* copy the Src mac addr */

	memcpy(ethernet_header->h_source, (void *)ether_aton(src_mac), 6);

	/* copy the Dst mac addr */

	memcpy(ethernet_header->h_dest, (void *)ether_aton(dst_mac), 6);

	/* copy the protocol */

	ethernet_header->h_proto = htons(protocol);

	/* done ...send the header back */

	return ((unsigned char *)ethernet_header);


}



/* argv[1] is the device e.g. eth0    */
 
main(int argc, char **argv)
{

	int raw;
	unsigned char *packet;
	int ethhdr_len;

	/* Create the raw socket */

	raw = CreateRawSocket(ETH_P_ALL);

	/* Bind raw socket to interface */

	BindRawSocketToInterface(argv[1], raw, ETH_P_ALL);

	/* create Ethernet header */

	packet = CreateEthernetHeader(SRC_ETHER_ADDR, DST_ETHER_ADDR, ETHERTYPE_IP);

	ethhdr_len = sizeof(struct ethhdr);


	if(!SendRawPacket(raw, packet, ethhdr_len))
	{
		perror("Error sending packet");
	}
	else
		printf("Packet sent successfully\n");

	/* Free the ethernet_header back to the heavenly heap */

	free(packet);

	close(raw);

	return 0;
}