I am creating a Messenger which is same as IP Messenger in Python 2.7 and Windows.
I want the same functionality as IP Messenger uses in finding the systems running same software over LAN but I am unable to understand the technique.
Can someone please help me to solve the problem of Finding the computers IP address or host name running same software over the LAN using Python 2.7 and Sockets Library.
Please suggest something which can be implemented on Windows not like Nmap(limited to linux) and it will be very helpful if solution is Python's Socket Library code.
" net view " command of Windows command prompt solved my problem stated in question.
By this command I am able to find all the computers connected to my computer through LAN and then I will send packets to all computers and computers replying to my packet would be the systems running same software as I am running which completely solved my problem.
This code lists out all the computers host names connected with my computer over LAN.
import os
os.system('net view > conn.tmp')
f = open('conn.tmp', 'r')
f.readline();f.readline();f.readline()
conn = []
host = f.readline()
while host[0] == '\\':
conn.append(host[2:host.find(' ')])
host = f.readline()
print conn
f.close()
seanhodges
What you are looking to do is a ping the local network for live nodes. Something like this script using Scapy might be sufficient. This pure-python implementation could be another more lightweight alternative.
In order to get the current IP address, you might want to follow one of the solutions given in this question.
An extension of the aforementioned Ping class could allow you to pull the results back for reading:
# TODO: This is a quick hack to retrieve the results
# of the ping, you should probably do something a bit more elegant here!
class PingQuery(Ping):
def __init__():
super().__init__()
result = false
def print_success(self, delay, ip, packet_size, ip_header, icmp_header):
result = ip
You could then loop through the addresses in the subnet to find your list of active machines:
subnet = "192.168.0." # TODO: Trim the last number off the IP address retrieved earlier
for i in range(1, 255):
hostname = subnet + i
p = PingQuery(hostname, 500, 55) # Timeout after 500ms per node
p.run(1)
if (p.result):
print p.result + " is live"
After that you can interrogate the live machines by attempting to connect to each machine with your port of choice, checking for a specially tailored TCP packet that proves the listening program is in fact your software.
Based on the answer by aki92...
import re
import subprocess
# ...
nodes = re.findall(r'\\(.+?)(?: .*)?\n',subprocess.check_output('net view'))
Added http layer with JSON Response using Simple HttpServer.
import time
import socket
import struct
import select
import random
import json
import asyncore
from netaddr import IPNetwork
import BaseHTTPServer
# From /usr/include/linux/icmp.h; your milage may vary.
ICMP_ECHO_REQUEST = 8 # Seems to be the same on Solaris.
ICMP_CODE = socket.getprotobyname('icmp')
ERROR_DESCR = {
1: ' - Note that ICMP messages can only be '
'sent from processes running as root.',
10013: ' - Note that ICMP messages can only be sent by'
' users or processes with administrator rights.'
}
__all__ = ['create_packet', 'do_one', 'verbose_ping', 'PingQuery',
'multi_ping_query']
HOST_NAME = '0.0.0.0' # !!!REMEMBER TO CHANGE THIS!!!
PORT_NUMBER = 9000 # Maybe set this to 9000.
SUBNET = '10.10.20.1/24'
host_list = []
"""
Below class would handle all rest requests
"""
class MyHandler(BaseHTTPServer.BaseHTTPRequestHandler):
def do_HEAD(self,s):
s.send_response(200)
s.send_header("Content-type", "text/html")
s.end_headers()
def do_GET(s):
"""Respond to a GET request."""
s.send_response(200)
s.send_header("content_disposition", "attachment; filename=serverstatus.json")
s.send_header("Content-type", "text/json")
s.end_headers()
for ip in IPNetwork(SUBNET):
host_list.append(ip.format(None))
#Create Object of SubnetMonitor
monitor = SubnetMonitor()
responseData = {}
for host, ping in monitor.multi_ping_query(host_list).iteritems():
if ping is not None:
print(host,'()',socket.gethostbyname(host) , '=', ping)
responseData[host] = 'Is Up'
else:
responseData[host] = 'Is Down'
json_data = json.dumps(responseData, sort_keys=True, indent=4, separators=(',', ': '))
s.wfile.write(json_data)
"""
Below class is used to send/receive all ping/icmp requests
"""
class PingQuery(asyncore.dispatcher):
def __init__(self, host, p_id, timeout=0.5, ignore_errors=False,monitor=None):
"""
Derived class from "asyncore.dispatcher" for sending and
receiving an icmp echo request/reply.
Usually this class is used in conjunction with the "loop"
function of asyncore.
Once the loop is over, you can retrieve the results with
the "get_result" method. Assignment is possible through
the "get_host" method.
"host" represents the address under which the server can be reached.
"timeout" is the interval which the host gets granted for its reply.
"p_id" must be any unique integer or float except negatives and zeros.
If "ignore_errors" is True, the default behaviour of asyncore
will be overwritten with a function which does just nothing.
"""
self.monitor = monitor
asyncore.dispatcher.__init__(self)
try:
self.create_socket(socket.AF_INET, socket.SOCK_RAW, ICMP_CODE)
except socket.error as e:
if e.errno in ERROR_DESCR:
# Operation not permitted
raise socket.error(''.join((e.args[1], ERROR_DESCR[e.errno])))
raise # raise the original error
self.time_received = 0
self.time_sent = 0
self.timeout = timeout
# Maximum for an unsigned short int c object counts to 65535 so
# we have to sure that our packet id is not greater than that.
self.packet_id = int((id(timeout) / p_id) % 65535)
self.host = host
self.packet = self.monitor.create_packet(self.packet_id)
if ignore_errors:
# If it does not care whether an error occured or not.
self.handle_error = self.do_not_handle_errors
self.handle_expt = self.do_not_handle_errors
def writable(self):
return self.time_sent == 0
def handle_write(self):
self.time_sent = time.time()
while self.packet:
# The icmp protocol does not use a port, but the function
# below expects it, so we just give it a dummy port.
sent = self.sendto(self.packet, (self.host, 1))
self.packet = self.packet[sent:]
def readable(self):
# As long as we did not sent anything, the channel has to be left open.
if (not self.writable()
# Once we sent something, we should periodically check if the reply
# timed out.
and self.timeout < (time.time() - self.time_sent)):
self.close()
return False
# If the channel should not be closed, we do not want to read something
# until we did not sent anything.
return not self.writable()
def handle_read(self):
read_time = time.time()
packet, addr = self.recvfrom(1024)
header = packet[20:28]
type, code, checksum, p_id, sequence = struct.unpack("bbHHh", header)
if p_id == self.packet_id:
# This comparison is necessary because winsocks do not only get
# the replies for their own sent packets.
self.time_received = read_time
self.close()
def get_result(self):
"""Return the ping delay if possible, otherwise None."""
if self.time_received > 0:
return self.time_received - self.time_sent
def get_host(self):
"""Return the host where to the request has or should been sent."""
return self.host
def do_not_handle_errors(self):
# Just a dummy handler to stop traceback printing, if desired.
pass
def create_socket(self, family, type, proto):
# Overwritten, because the original does not support the "proto" arg.
sock = socket.socket(family, type, proto)
sock.setblocking(0)
self.set_socket(sock)
# Part of the original but is not used. (at least at python 2.7)
# Copied for possible compatiblity reasons.
self.family_and_type = family, type
# If the following methods would not be there, we would see some very
# "useful" warnings from asyncore, maybe. But we do not want to, or do we?
def handle_connect(self):
pass
def handle_accept(self):
pass
def handle_close(self):
self.close()
class SubnetMonitor:
def __init__(self):
print("Subnet Monitor Started")
def checksum(self,source_string):
# I'm not too confident that this is right but testing seems to
# suggest that it gives the same answers as in_cksum in ping.c.
sum = 0
count_to = (len(source_string) / 2) * 2
count = 0
while count < count_to:
this_val = ord(source_string[count + 1])*256+ord(source_string[count])
sum = sum + this_val
sum = sum & 0xffffffff # Necessary?
count = count + 2
if count_to < len(source_string):
sum = sum + ord(source_string[len(source_string) - 1])
sum = sum & 0xffffffff # Necessary?
sum = (sum >> 16) + (sum & 0xffff)
sum = sum + (sum >> 16)
answer = ~sum
answer = answer & 0xffff
# Swap bytes. Bugger me if I know why.
answer = answer >> 8 | (answer << 8 & 0xff00)
return answer
def create_packet(self,id):
"""Create a new echo request packet based on the given "id"."""
# Header is type (8), code (8), checksum (16), id (16), sequence (16)
header = struct.pack('bbHHh', ICMP_ECHO_REQUEST, 0, 0, id, 1)
data = 192 * 'Q'
# Calculate the checksum on the data and the dummy header.
my_checksum = self.checksum(header + data)
# Now that we have the right checksum, we put that in. It's just easier
# to make up a new header than to stuff it into the dummy.
header = struct.pack('bbHHh', ICMP_ECHO_REQUEST, 0,
socket.htons(my_checksum), id, 1)
return header + data
def do_one(self,dest_addr, timeout=1):
"""
Sends one ping to the given "dest_addr" which can be an ip or hostname.
"timeout" can be any integer or float except negatives and zero.
Returns either the delay (in seconds) or None on timeout and an invalid
address, respectively.
"""
try:
my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, ICMP_CODE)
except socket.error as e:
if e.errno in ERROR_DESCR:
# Operation not permitted
raise socket.error(''.join((e.args[1], ERROR_DESCR[e.errno])))
raise # raise the original error
try:
host = socket.gethostbyname(dest_addr)
except socket.gaierror:
return
# Maximum for an unsigned short int c object counts to 65535 so
# we have to sure that our packet id is not greater than that.
packet_id = int((id(timeout) * random.random()) % 65535)
packet = self.create_packet(packet_id)
while packet:
# The icmp protocol does not use a port, but the function
# below expects it, so we just give it a dummy port.
sent = my_socket.sendto(packet, (dest_addr, 1))
packet = packet[sent:]
delay = self.receive_ping(my_socket, packet_id, time.time(), timeout)
my_socket.close()
return delay
def receive_ping(self,my_socket, packet_id, time_sent, timeout):
# Receive the ping from the socket.
time_left = timeout
while True:
started_select = time.time()
ready = select.select([my_socket], [], [], time_left)
how_long_in_select = time.time() - started_select
if ready[0] == []: # Timeout
return
time_received = time.time()
rec_packet, addr = my_socket.recvfrom(1024)
icmp_header = rec_packet[20:28]
type, code, checksum, p_id, sequence = struct.unpack(
'bbHHh', icmp_header)
if p_id == packet_id:
return time_received - time_sent
time_left -= time_received - time_sent
if time_left <= 0:
return
def verbose_ping(self,dest_addr, timeout=2, count=4):
"""
Sends one ping to the given "dest_addr" which can be an ip or hostname.
"timeout" can be any integer or float except negatives and zero.
"count" specifies how many pings will be sent.
Displays the result on the screen.
"""
for i in range(count):
print('ping {}...'.format(dest_addr))
delay = self.do_one(dest_addr, timeout)
if delay == None:
print('failed. (Timeout within {} seconds.)'.format(timeout))
else:
delay = round(delay * 1000.0, 4)
print('get ping in {} milliseconds.'.format(delay))
print('')
def multi_ping_query(self,hosts, timeout=1, step=512, ignore_errors=False):
"""
Sends multiple icmp echo requests at once.
"hosts" is a list of ips or hostnames which should be pinged.
"timeout" must be given and a integer or float greater than zero.
"step" is the amount of sockets which should be watched at once.
See the docstring of "PingQuery" for the meaning of "ignore_erros".
"""
results, host_list, id = {}, [], 0
for host in hosts:
try:
host_list.append(socket.gethostbyname(host))
except socket.gaierror:
results[host] = None
while host_list:
sock_list = []
for ip in host_list[:step]: # select supports only a max of 512
id += 1
sock_list.append(PingQuery(ip, id, timeout, ignore_errors,self))
host_list.remove(ip)
# Remember to use a timeout here. The risk to get an infinite loop
# is high, because noone can guarantee that each host will reply!
asyncore.loop(timeout)
for sock in sock_list:
results[sock.get_host()] = sock.get_result()
return results
if __name__ == '__main__':
server_class = BaseHTTPServer.HTTPServer
httpd = server_class((HOST_NAME, PORT_NUMBER), MyHandler)
print time.asctime(), "Server Starts - %s:%s" % (HOST_NAME, PORT_NUMBER)
try:
httpd.serve_forever()
except KeyboardInterrupt:
pass
httpd.server_close()
print time.asctime(), "Server Stops - %s:%s" % (HOST_NAME, PORT_NUMBER)
来源：https://stackoverflow.com/questions/15464387/finding-live-nodes-on-lan-using-python