#!/usr/bin/env python
#
# Author: Martin Matusiak <numerodix@gmail.com>
# Licensed under the GNU Public License, version 2.
#
# revision 2 - add hostname lookup


import os, string, re, sys, time, thread


def main():
	network = None
	try:
		netinfo = check_network()
		(ip, mask) = netinfo
		network = ip + "/" + mask
	except:
		print "Warning: No network connection found, scan may fail."

	if len(sys.argv) > 1:
		network = sys.argv[1]

	if not network:
		print "Error: No network range given."
		print "Usage:\t" + sys.argv[0] + " 10.0.0.0/24"
		sys.exit(1)


	if cmd_exists("nmap"):
		nmap_scan(network)
	else:
		print "Warning: nmap not found, falling back on failsafe ping scan method."
		ping_scan(network)


def nmap_scan(network):
	try:
		print "Using network: " + network
		cmd = 'nmap -n -sP -T4 ' + network + ' 2>&1'
		res = invoke(cmd)
		lines = res.split('\n')
		for i in lines:
			m = find('Host\s+\(?([0-9\.]+)\)?\s+appears to be up.', i)
			if m:
				print m, "\t", nslookup(m)
	except: pass


def ping_scan(network):
	iprange = find('(\w+\.\w+\.\w+)', network)
	print "Using network: " + iprange + ".0/24"
	for i in range(1,254):
		host = iprange + '.' + str(i)
		thread.start_new_thread(ping, (host, None))
		time.sleep(1)


def ping(host, dummy):
	try:
		cmd = 'ping -c3 -n -w300 ' + host + ' 2>&1'
		res = invoke(cmd)
		if "bytes from" in res: print host, "\t", nslookup(host)
	except: pass


def nslookup(ip):
	if cmd_exists("host"):
		cmd = 'host ' + ip + ' 2>&1'
		res = invoke(cmd)
		if "domain name pointer" in res:
			return res.split(" ")[4][:-2]
	return ""


def check_network():
	cmd = "/sbin/ifconfig"
	res = invoke(cmd)

	iface, ip, mask = None, None, None
	lines = res.split('\n')
	for i in lines:
		
		# find interface
		m = find('^(\w+)\s+', i)
		if m: iface = m
		
		# ignore loopback interface
		if iface and iface != "lo":
			
			# find ip address
			m = find('inet addr:([0-9\.]+)\s+', i)
			if m: ip = m
			
			# find net mask
			m = find('Mask:([0-9\.]+)$', i)
			if m: mask = m

	if ip and mask:
		mask = mask_numerical(mask)
		return (ip, mask)


def mask_numerical(mask):
	segs = find('(\w+)\.(\w+)\.(\w+)\.(\w+)', mask)
	mask = 0
	adds = (0, 128, 192, 224, 240, 248, 252, 254, 255)
	for i in segs:
		for j in range(0, len(adds)):
			if int(i) == adds[j]:
				mask += j
	return str( mask )


def find(needle, haystack):
	try:
		match = re.search(needle, haystack)
		if len(match.groups()) > 1:
			return match.groups()
		else: 
			return match.groups()[0]
	except: pass


def invoke(cmd):
	(sin, sout) = os.popen2(cmd)
	return sout.read()


def cmd_exists(cmd):
	if invoke("which " + cmd + " 2>&1").find("no " + cmd) == -1:
		return True
	return False



if __name__ == "__main__":
	main()