rawether.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <errno.h>

int main()
{
    int s;          /*socketdescriptor */
    char *opt;
    opt = "wlan0";

    s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
    if (s == -1) {
        printf("error creating socket\n");
        exit(-1);
    }
    setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, opt, 5);
//#define ETH_FRAME_LEN 1518

/*target address*/
    struct sockaddr_ll socket_address;

/*buffer for ethernet frame*/
    void *buffer = (void *)malloc(ETH_FRAME_LEN);

/*pointer to ethenet header*/
    unsigned char *etherhead = buffer;

/*userdata in ethernet frame*/
    unsigned char *data = buffer + 14;

/*another pointer to ethernet header*/
    struct ethhdr *eh = (struct ethhdr *)etherhead;

    int send_result = 0;

/*our MAC address*/
    unsigned char src_mac[6] = { 0x00, 0x26, 0xc7, 0x0c, 0xc4, 0x8e };

/*other host MAC address*/
    unsigned char dest_mac[6] = { 0x00, 0x1d, 0x60, 0x66, 0x6d, 0x12 };

/*prepare sockaddr_ll*/

/*RAW communication*/
    socket_address.sll_family = PF_PACKET;
/*we don't use a protocoll above ethernet layer
  ->just use anything here*/
    socket_address.sll_protocol = htons(ETH_P_IP);

/*index of the network device
see full code later how to retrieve it*/
    socket_address.sll_ifindex = 2;

/*ARP hardware identifier is ethernet*/
    socket_address.sll_hatype = ARPHRD_ETHER;

/*target is another host*/
    socket_address.sll_pkttype = PACKET_OTHERHOST;

/*address length*/
    socket_address.sll_halen = ETH_ALEN;
/*MAC - begin*/
    socket_address.sll_addr[0] = dest_mac[0];
    socket_address.sll_addr[1] = dest_mac[1];
    socket_address.sll_addr[2] = dest_mac[2];

    socket_address.sll_addr[3] = dest_mac[3];
    socket_address.sll_addr[4] = dest_mac[4];
    socket_address.sll_addr[5] = dest_mac[5];
/*MAC - end*/
    socket_address.sll_addr[6] = 0x00;  /*not used */
    socket_address.sll_addr[7] = 0x00;  /*not used */

/*set the frame header*/
    memcpy((void *)buffer, (void *)dest_mac, ETH_ALEN);
    memcpy((void *)(buffer + ETH_ALEN), (void *)src_mac, ETH_ALEN);
    eh->h_proto = 0x00;
/*fill the frame with some data*/
    int j;
    for (j = 0; j < 1500; j++) {
        data[j] =
            (unsigned char)((int)(255.0 * rand() / (RAND_MAX + 1.0)));
    }

/*send the packet*/
    send_result =
        sendto(s, buffer, ETH_FRAME_LEN, 0,
           (struct sockaddr *)&socket_address, sizeof(socket_address));
    if (send_result == -1) {
        printf("sendto: %s (%d)\n", strerror(errno), errno);
    }
}