send_raw_ethernet.c

/*
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 * Original version from Austin Martin:
 * https://gist.github.com/austinmarton/1922600
 *
 * Adapted by Paul Craven
 */

#include <arpa/inet.h>
#include <linux/if_packet.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <unistd.h>

/* ALERT: Replace the bytes below with the MAC address
   you are sending to.
   So if 'ifconfig' on the RECEIVER (not the sender) says:
   wlan0     Link encap:Ethernet  HWaddr b8:27:eb:44:08:62
   You'd replace the bytes below with:
   #define DEST_MAC0 0xB8
   #define DEST_MAC1 0x27
   #define DEST_MAC2 0xEB
   #define DEST_MAC3 0x44
   #define DEST_MAC4 0x08
   #define DEST_MAC5 0x62
*/

#define DEST_MAC0    0xB8
#define DEST_MAC1    0x27
#define DEST_MAC2    0xEB
#define DEST_MAC3    0x44
#define DEST_MAC4    0x08
#define DEST_MAC5    0x62

/* ALERT: Update the field below to specify what network 
  adapter should we send data through. */
#define DEFAULT_IF  "wlan0"

#define BUF_SIZ     1024

int main(int argc, char *argv[])
{
    int sockfd;
    int i;
    struct ifreq if_idx;
    struct ifreq if_mac;
    int tx_len;
    char sendbuf[BUF_SIZ];
    struct sockaddr_ll socket_address;
    char ifName[IFNAMSIZ];

    /* Get interface name */
    if (argc > 1)
        strcpy(ifName, argv[1]);
    else
        strcpy(ifName, DEFAULT_IF);

    /* Open RAW socket to send on */
    if ((sockfd = socket(AF_PACKET, SOCK_RAW, IPPROTO_RAW)) == -1) {
        perror("socket");
    }

    /* Get the index of the interface to send on */
    memset(&if_idx, 0, sizeof(struct ifreq));
    strncpy(if_idx.ifr_name, ifName, IFNAMSIZ-1);
    if (ioctl(sockfd, SIOCGIFINDEX, &if_idx) < 0)
        perror("SIOCGIFINDEX");

    /* Get the MAC address of the interface to send on */
    memset(&if_mac, 0, sizeof(struct ifreq));
    strncpy(if_mac.ifr_name, ifName, IFNAMSIZ-1);
    if (ioctl(sockfd, SIOCGIFHWADDR, &if_mac) < 0)
        perror("SIOCGIFHWADDR");

    // Loop forever
    while(1) {


        /* Buffer of BUF_SIZ bytes we'll construct our frame in.
           First, clear it all to zero. */
        memset(sendbuf, 0, BUF_SIZ);
        tx_len = 0;

        /* Construct the Ethernet header */

        /* Ethernet header */
        /* Destination address */
        sendbuf[tx_len++] = DEST_MAC0;
        sendbuf[tx_len++] = DEST_MAC1;
        sendbuf[tx_len++] = DEST_MAC2;
        sendbuf[tx_len++] = DEST_MAC3;
        sendbuf[tx_len++] = DEST_MAC4;
        sendbuf[tx_len++] = DEST_MAC5;

        /* Create the source */
        sendbuf[tx_len++] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[0];
        sendbuf[tx_len++] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[1];
        sendbuf[tx_len++] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[2];
        sendbuf[tx_len++] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[3];
        sendbuf[tx_len++] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[4];
        sendbuf[tx_len++] = ((uint8_t *)&if_mac.ifr_hwaddr.sa_data)[5];

        /* Ethertype field */
        sendbuf[tx_len++] = 0x08;
        sendbuf[tx_len++] = 0x00;

        /*
        UPDATE: Packet data
        This is the 'payload'. Replace this with your real data.
        Because you'll probably have more interesting things to send
        than the hex 0xDEAD 0xBEEF
        */
        sendbuf[tx_len++] = 0xde;
        sendbuf[tx_len++] = 0xad;
        sendbuf[tx_len++] = 0xbe;
        sendbuf[tx_len++] = 0xef;

        /* Index of the network device */
        socket_address.sll_ifindex = if_idx.ifr_ifindex;
        /* Address length*/
        socket_address.sll_halen = ETH_ALEN;
        /* Destination MAC */
        socket_address.sll_addr[0] = DEST_MAC0;
        socket_address.sll_addr[1] = DEST_MAC1;
        socket_address.sll_addr[2] = DEST_MAC2;
        socket_address.sll_addr[3] = DEST_MAC3;
        socket_address.sll_addr[4] = DEST_MAC4;
        socket_address.sll_addr[5] = DEST_MAC5;

        /* Send packet */
        if (sendto(sockfd, sendbuf, tx_len, 0, (struct sockaddr*)&socket_address, sizeof(struct sockaddr_ll)) < 0)
            printf("Send failed\n");
        else {
            printf("Sent :");
            for (i=0; i < tx_len; i++)
                printf("%02x:", sendbuf[i]);
            printf("\n");
        }
        /* Wait specified number of microseconds
           1,000,000 microseconds = 1 second
           */
        usleep(1000000);
    }
    return 0;
}