Programming

#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>


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;
	
}

void PrintPacketInHex(unsigned char *packet, int len)
{
	unsigned char *p = packet;

	printf("\n\n---------Packet---Starts----\n\n");
	
	while(len--)
	{
		printf("%.2x ", *p);
		p++;
	}

	printf("\n\n--------Packet---Ends-----\n\n");

}


main(int argc, char **argv)
{
	int raw;
	unsigned char packet_buffer[2048]; 
	int len;
	int packets_to_sniff;
	struct sockaddr_ll packet_info;
	int packet_info_size = sizeof(packet_info);

	/* create the raw socket */

	raw = CreateRawSocket(ETH_P_IP);

	/* Bind socket to interface */

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

	/* Get number of packets to sniff from user */

	packets_to_sniff = atoi(argv[2]);

	/* Start Sniffing and print Hex of every packet */
	
	while(packets_to_sniff--)
	{
		if((len = recvfrom(raw, packet_buffer, 2048, 0, (struct sockaddr*)&packet_info, &packet_info_size)) == -1)
		{
			perror("Recv from returned -1: ");
			exit(-1);
		}
		else
		{
			/* Packet has been received successfully !! */

			PrintPacketInHex(packet_buffer, len);
		}
	}
	
	
	return 0;
}