#! /usr/bin/python

import os as OS
from sys import stdout, argv
import impacket.ImpactPacket as I

sndname, sndaddr, rcpname, rcpaddr, outfile = argv[1:]

ip = I.IP()
ip.set_ip_src(sndaddr);
ip.set_ip_dst(rcpaddr);
icmp = I.ICMP()
icmp.set_icmp_type(icmp.ICMP_ECHO)
icmp.set_icmp_cksum(0)
icmp.auto_checksum = 1
icmp.contains(I.Data('Hello, %s, from %s!' % (rcpname, sndname)))
ip.contains(icmp)

if outfile == '-':
  stdout.write(ip.get_packet())
else:
  outtmp = outfile + '.new'
  with open(outtmp, 'wb') as f: f.write(ip.get_packet())
  OS.rename(outtmp, outfile)