#!/usr/bin/env python
# Copyright (c) 2006, Neville-Neil Consulting
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# File: $Id: ping.py,v 1.3 2006/09/05 07:30:56 gnn Exp $
#
# Author: George V. Neville-Neil
#
# Description: A simple re-implementatoin of the ping(8) program in
# Python using the Packet Construction Set

from pcs.packets.localhost import *
from pcs.packets.ethernet import *
from pcs.packets.ipv4 import *
from pcs.packets.icmpv4 import *
from pcs import *

def main():

    from optparse import OptionParser
    
    parser = OptionParser()
    parser.add_option("-c", "--count",
                      dest="count", default=1,
                      help="Stop after sending (and recieving) count ECHO_RESPONSE packets..")
    
    parser.add_option("-D", "--dont_fragment",
                      dest="df", default=False,
                      help="Set the Don't Fragment bit.")
    
    parser.add_option("-s", "--ip_source",
                      dest="ip_source", default=None,
                      help="The IP source address.")

    parser.add_option("-d", "--ip_dest",
                      dest="ip_dest", default=None,
                      help="The IP destination address.")

    parser.add_option("-e", "--ether_source",
                      dest="ether_source", default=None,
                      help="The host Ethernet source address.")

    parser.add_option("-g", "--ether_dest",
                      dest="ether_dest", default=None,
                      help="The gateway Ethernet destination address.")

    (options, args) = parser.parse_args()
    
    # Set up the vanilla packet
    ip = ipv4()
    ip.version = 4
    ip.hlen = 5
    ip.tos = 0
    ip.length = 84
    ip.id = 1
    ip.flags = 0
    ip.offset = 0
    ip.ttl = 64
    ip.protocol = IPPROTO_ICMP
    ip.src = inet_atol(options.ip_source)
    ip.dst = inet_atol(options.ip_dest)
    ip.checksum = ip.calc_checksum()
    
    icmp = icmpv4()
    icmp.type = 8
    icmp.code = 0
    icmp.cksum = 0
    
    echo = icmpv4echo()
    echo.id = 12345
    echo.seq = 0
    
    icmp_packet = Chain([icmp, echo])
    icmp.checksum = icmp_packet.calc_checksum()
    
    ether = ethernet()
    ether.type = 0x800
    ether.src = ether_atob(options.ether_source)
    ether.dst = ether_atob(options.ether_dest)
    packet = Chain([ether, ip, icmp, echo])

    input = PcapConnector("en0")
    input.setfilter("icmp")
    
    output = PcapConnector("en0")
    
    count = 0
    while (count < options.count):
        out = output.write(packet.bytes, len(packet.bytes))
#        packet = input.read()
#        print packet
        count += 1
main()