#!/usr/bin/env python2
#
# ./find_dns.py -l IPs.txt -t 500 -o dnsservers.txt
#
# dns-server finder by dash
# 
#
#./find_dns.py -l rIP.txt -t 100 
#[*] Found 1001 entries
#[*] Entries 1001 in queue
#[*] Running with 100 threads
#==================================================
#IP          NAME
#==================================================
#91.x.x.x   (x.info)
#191.x.x.x  (191.x.br)
#67.x.x.x   (name.info)
#==================================================
#[*] Done
#

import os
import sys
import time
import Queue
import struct
import socket
import random
import argparse
import threading

global rQ
rQ = Queue.Queue()

def openFile(hostList):
  fr = open(hostList,'r')
  rBuf = fr.readlines()
  return rBuf

def openWriteFile(outfile):
  fw = open(outfile,'wb')
  return fw

def parseDomain(domain):
  do = domain.split('.')
  if len(do) != 2:
    print '[!] Sorry, unknown domain type: %s\nExample:google.com' % (domain)
    return False
  tld = do[1]
  tld_len = struct.pack('>B', len(tld))
  tld_sub = do[0]
  tld_sub_len = struct.pack('>B', len(tld_sub))
  dom_pay = '%c%s%c%s' % (tld_sub_len,tld_sub,tld_len,tld)
  return dom_pay
  
  

def checkDNS(payload,host,resolv,debug,version):
  # settimeout so recv is not block
  rBuf_len = -1
  try:
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.settimeout(5)
    s.connect((host,53))
    s.send(payload)
    rBuf = s.recv(1024)
    rBuf_len = len(rBuf)
    name = ''
    # default we resolve IPs as long as -n is not choosen
    if resolv:
      try:
        name = socket.gethostbyaddr(host)[0]
      except socket.herror,e:
        pass

    if version:
      # FEFE packet!
      ver_req = '\xfe\xfe\x01 \x00\x01\x00\x00\x00\x00\x00\x01\x07version\x04bind\x00\x00\x10\x00\x03\x00\x00)\x10\x00\x00\x00\x00\x00\x00\x00'
      try:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        s.settimeout(3)
        s.connect((host,53))
        s.send(ver_req)
        vBuf = s.recv(1024)
      except socket.error,e:
        vBuf = ''
        pass
        

    if name == '':
      if debug:
        print '%s\t%d\t%s\t%s' % (host,rBuf_len,repr(rBuf),repr(vBuf))
        data = '%s\t%d\t%s\t%s\n' % (host,rBuf_len,repr(rBuf),repr(vBuf))
      else:
        print '%s\t%d' % (host,rBuf_len)
        data = '%s\t%d\n' % (host,rBuf_len)
    else:
      if debug:
        print '%s\t(%s) %d\t%s' % (host,name,rBuf_len,repr(rBuf))
        data = '%s\t(%s) %d\t%s\n' % (host,name,rBuf_len,repr(rBuf))
      else:
        print '%s\t(%s) %d' % (host,name,rBuf_len)
        data = '%s\t(%s) %d\n' % (host,name,rBuf_len)

    rQ.put(data)
  except socket.error,e:
#    print e
    pass
  return
    
def run(args):
  """ mighty mighty function """

  if not args.thrCnt:
    thrCnt=50
  else:
    thrCnt = int(args.thrCnt)
  
  if args.outfile:
    fw = openWriteFile(args.outfile)

  dom_pay = parseDomain(args.domain)
  payload = 'J\x8e\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00%s\x00\x00\x01\x00\x01' % (dom_pay)
  
  hostList = args.hostList

  q = Queue.Queue()
  rBuf = openFile(hostList)
  print '[*] Found %d entries' % len(rBuf)
  for r in rBuf:
    r = r.rstrip('\n')
    r = r.rstrip('\r')
    q.put(r)

  print '[*] Entries %d in queue' % q.qsize()
  print '[*] Running with %d threads' % thrCnt
  print '='*50
  if args.resolv:
    print 'IP\t\tNAME\tPAYLEN'
  else:
    print 'IP\t\tPAYLEN'

  print '='*50
  thrList = []
  org_qlen = float(q.qsize())
  while True:
    
    #TODO percents calc
    #qlen = q.qsize()
    #cur_cnt = (qlen / org_qlen) * 100
    #cur_cnt = int(100 - cur_cnt)
    #if cur_cnt % 5 == 0 and cur_cnt != 0:
      #print '='*20+' %d ' % (cur_cnt)+'='*20

    if len(thrList) < thrCnt and q.qsize()>0:

      # enable random transaction ids
      if args.randTrans:
        rd = random.randint(0,65535)
        rd_pack = struct.pack('>H',rd)
        payload = '%s%s' % (rd_pack,payload[2:]) 

      thrDns = threading.Thread(target = checkDNS, args = (payload,q.get(),args.resolv,args.debug,args.version))
      thrDns.daemon = True
      thrDns.start()
      thrList.append(thrDns)
    
    for entry in thrList:
      if entry.isAlive()==False:
        entry.join()
        thrList.remove(entry)

    if args.outfile and rQ.qsize()>0:
      i = rQ.get()
      data = "%s" % (i)
      fw.write(data)
      fw.flush()
    else:
      if rQ.qsize()>0:
        rQ.get()

    if q.qsize()==0 and len(thrList) == 0:
      break
  
  if args.outfile:
    fw.close()
  print '='*50
  print '[*] Done'
  print '='*50
  

def main():
  parser_desc = 'dns server finder, by dash'
  prog_desc = 'find_dns.py'
  parser = argparse.ArgumentParser(  prog = prog_desc, description = parser_desc)
  parser.add_argument("-l",action='store',required=True,help='host list with ips',dest='hostList')
  parser.add_argument('-t',action='store',required=False,help='thread count', dest='thrCnt')
  parser.add_argument('-o',action='store',required=False,help='write found data to file', dest='outfile')
  parser.add_argument('-n',action='store_false',default=True,required=False,help='do not resolve ips', dest='resolv')
  parser.add_argument('-d',action='store',default='google.com',required=False,help='choose the domain for the dns request', dest='domain')
  parser.add_argument('-r',action='store_false',default=True,required=False,help='deactivate random transaction ids', dest='randTrans')
  parser.add_argument('-v',action='store_true',default=False,required=False,help='grab version from dns server enable debug mode for it! (experimental!)', dest='version')
  parser.add_argument('-V',action='store_true',default=False,required=False,help='print version information', dest='versinfo')
  parser.add_argument('--debug',action='store_true',default=False,required=False,help='debug output', dest='debug')

  args = parser.parse_args()
  # add some more info here sometime
  if args.versinfo:
    print desc
    sys.exit(23)

  run(args)

if __name__ == "__main__":
  main()