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sendpcap.py

#!/usr/bin/env python
# -*- coding: UTF-8 -*-
#Resend packets in pcap file
#Created 7/30/2016, thimer
import struct
import socket
import sys
import time

def hexofbin(bin, show=4):
  size = len(bin)
  s = '%4d - ' % size
  if size > show * 2:
    s += bin[:show].encode('hex')
    s += ' ... '
    s += bin[-show:].encode('hex')
  else:
    s+= bin.encode('hex')
  return s

def send_udp(data, host, port=80):
  print 'Send UDP: %s/%d <= %s' % (host, port, hexofbin(data))
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  sock.sendto(data, (host, port))

class Parser:

  def __init__(self, filename):
    self.fh = open(filename, 'rb')
    self.global_header()

  def __del__(self):
    self.fh.close()

  def global_header(self):
    hdr_fmt = '=IHHiIII'
    hdr_len = struct.calcsize(hdr_fmt)
    hdr_unpack = struct.Struct(hdr_fmt).unpack_from
    data = self.fh.read(hdr_len)
    if not data:
      return None
    s = hdr_unpack(data)
    #print s
    (magic_number, ver_major, ver_minor, thiszone, sigfigs, snaplen, network) = s
    self.version = (ver_major, ver_minor)
    self.snaplen = snaplen
    self.ts0 = 0
    self.index = 0
    return magic_number

  def packet(self):
    hdr_fmt = '=4I'
    hdr_len = struct.calcsize(hdr_fmt)
    hdr_unpack = struct.Struct(hdr_fmt).unpack_from
    data = self.fh.read(hdr_len)
    if not data:
      return None
    s = hdr_unpack(data)
    #print s
    (ts_sec, ts_usec, incl_len, orig_len) = s
    data = self.fh.read(incl_len)
    ts = ts_sec + ts_usec / 1000000.0
    if self.index == 0:
      self.ts0 = ts
    time = ts - self.ts0
    self.index += 1
    payload = data[42:]
    print '%4d, %7.3f, %4d > %s' % (self.index, time, orig_len, hexofbin(payload))
    if (incl_len != orig_len):
      print 'Warning: incl_len(%d) != orig_len(%d)' % (incl_len, orig_len)
    return (self.index, payload)

def help():
  print 'Usage: %s target-host pcap-file packet-index1 packet-index2 ...' % sys.argv[0]
  return -1

def sendpcap(host, pcapfile, indexes):
  #print indexes
  parser = Parser(pcapfile)
  while True:
    info = parser.packet()
    if info is None:
      break
    (index, payload) = info
    if index in indexes:
      send_udp(payload, host)
      #time.sleep(1)
  return 0

def main():
  if len(sys.argv) < 3:
    return help()
  host = sys.argv[1]
  pcapfile = sys.argv[2]
  indexes = map(int, sys.argv[3:])
  return sendpcap(host, pcapfile, indexes)

if __name__ == "__main__":
  main()