使用Python在LAN上查找实时节点

时间:2013-03-17 18:17:37

标签: python networking ip lan python-sockets

我正在创建一个与Python 2.7和Windows中的IP Messenger相同的Messenger。

我想要与IP Messenger在查找通过LAN运行相同软件的系统中使用的功能相同,但我无法理解该技术。

有人可以帮我解决使用Python 2.7和套接字库找到运行相同软件的计算机IP地址或主机名 问题

请建议一些可以在Windows上实现的内容,而不是像Nmap(仅限于Linux),如果解决方案是Python的套接字库代码,它将非常有用。

4 个答案:

答案 0 :(得分:10)

Windows命令提示符的“ net view ”命令解决了我所述的问题。

通过此命令,我能够找到通过LAN连接到我的计算机的所有计算机,然后我将数据包发送到所有计算机和回复我的数据包的计算机将是运行与我运行相同的软件的系统,这完全解决了我的问题问题

此代码列出了通过LAN连接到我的计算机的所有计算机主机名。

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()    

答案 1 :(得分:2)

您要做的是ping本地网络中的实时节点。使用this scriptScapy之类的内容可能就足够了。这个pure-python implementation可能是另一个更轻量级的选择。

要获取当前的IP地址,您可能需要遵循this question中给出的解决方案之一。

前面提到的Ping类的扩展可以让你将结果拉回来阅读:

# 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

然后,您可以遍历子网中的地址以查找活动计算机列表:

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"

之后,您可以通过尝试使用您选择的端口连接到每台计算机来查询实时计算机,检查专门定制的TCP数据包,以证明监听程序实际上是您的软件。

答案 2 :(得分:0)

根据aki92的回答......

import re
import subprocess
# ...

nodes = re.findall(r'\\(.+?)(?: .*)?\n',subprocess.check_output('net view'))

答案 3 :(得分:0)

使用Simple HttpServer添加了带有JSON Response的http层。

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)