local_computers_scanner.py

#!/usr/bin/env python3

import socket
import subprocess
import os

connected_ips = []

def start():
	# Get ip and netmask
	ip = socket.gethostbyname(socket.gethostname())
	netmask = get_netmask(ip)
	print("Your ip: " + ip)
	print("Netmask: " + get_netmask(ip))

	# Define netmask depth
	depth = 0
	while(netmask.split('.')[depth] < '255'):
		depth+=1

	# Prepare basemask
	basemask = netmask.split('.')[:depth]
	d = depth
	while(d<=3):
		basemask.append('0')
		d+=1
	for d in range(len(basemask)):
		basemask[d] = int(basemask[d])
	print(basemask)

	# Check all ips recursively inside the mask
	test_rec(basemask, depth)
	print(connected_ips)

def test_rec(mask, depth):
	if depth == 3 and mask[3] < 255:
		ip = arrmask_to_str(mask)
		try_ip(ip)
		mask[3] += 1
		test_rec(mask, depth)
	elif mask[depth] < 255:
		test_rec(mask, depth+1)
		mask[3] = 0
		mask[depth] += 1
		test_rec(mask, depth)

def try_ip(ip):
	try:
		socket.gethostbyaddr(ip)
		connected_ips.append(ip)
		print("Device at " + ip)
	except socket.herror:
		pass
		#print("Unknown host: " + ip)

def get_netmask(ip):
	# Call ipconfig / ifconfig
	if (os.name == 'nt'): # If this is running on windows
		proc = subprocess.Popen('ipconfig',stdout=subprocess.PIPE)
		flag="Subnet Mask".encode()
	else: # else assume UNIX
		proc = subprocess.Popen('ifconfig',stdout=subprocess.PIPE)
		flag=ip.encode()

	while True:
	    line = proc.stdout.readline()
	    if flag in line:
	        break
	line = line.decode("utf-8")
	line = line.rstrip() # remove \n
	mask = line.split(' ')[-1] # Last ip in the message is broadcast
	return mask

def arrmask_to_str(mask):
	return (str(mask[0]) + '.' +
			str(mask[1]) + '.' +
			str(mask[2]) + '.' +
			str(mask[3]))

if __name__ == '__main__':
	start()