在Python中,是否有一种方法可以通过ICMP来ping服务器,如果服务器响应则返回TRUE,如果没有响应则返回FALSE ?


当前回答

在四处寻找之后,我最终编写了自己的ping模块,该模块旨在监视大量地址,是异步的,并且不使用大量系统资源。你可以在这里找到它:https://github.com/romana/multi-ping/它是Apache授权的,所以你可以在你的项目中以任何你认为合适的方式使用它。

实施我自己的方法的主要原因是其他方法的限制:

这里提到的许多解决方案都需要将exec输出到命令行实用程序。如果您需要监控大量的IP地址,这是非常低效和资源消耗的。 其他人提到了一些较老的python ping模块。我看了这些,最后,他们都有这样或那样的问题(比如没有正确设置数据包id),不能处理大量地址的ping-ing。

其他回答

如果您的服务器不支持ICMP(防火墙可能会阻止它),它很可能仍然在TCP端口上提供服务。在这种情况下,你可以像这样执行TCP ping1(平台独立,无需安装额外的python模块):

import socket

def isReachable(ipOrName, port, timeout=2):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(timeout)
    try:
        s.connect((ipOrName, int(port)))
        s.shutdown(socket.SHUT_RDWR)
        return True
    except:
        return False
    finally:
        s.close()

代码从这里开始只做了轻微的修改。


1 TCP ping并不真正存在,因为ping是在ISO/OSI第三层用ICMP执行的。TCP ping在ISO/OSI第4层执行。它只是试图以最基本的方式连接到TCP端口,即不传输任何数据,而是在连接后立即关闭连接。

使用这个,它在python 2.7上测试过,工作很好,如果成功,它返回以毫秒为单位的ping时间,失败时返回False。

import platform,subproccess,re
def Ping(hostname,timeout):
    if platform.system() == "Windows":
        command="ping "+hostname+" -n 1 -w "+str(timeout*1000)
    else:
        command="ping -i "+str(timeout)+" -c 1 " + hostname
    proccess = subprocess.Popen(command, stdout=subprocess.PIPE)
    matches=re.match('.*time=([0-9]+)ms.*', proccess.stdout.read(),re.DOTALL)
    if matches:
        return matches.group(1)
    else: 
        return False

在linux上,可以创建ICMP数据报(不是原始)套接字,而不需要root(或setuid或CAP_NET_RAW): https://unix.stackexchange.com/a/592914。最后我得到了

$ id
uid=1000(raylu) gid=1000(raylu) [...]
$ sudo sysctl net.ipv4.ping_group_range='1000 1000'
import socket
import struct
import time

def main():
    ping('192.168.1.10')

def ping(destination):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.getprotobyname('icmp'))
    sock.settimeout(10.0)
    start_time = time.time_ns() # python 3.7+ only

    payload = struct.pack('L', start_time)
    sock.sendto(encode(payload), (destination, 0))
    while (time.time_ns() - start_time) // 1_000_000_000 < 10:
        try:
            data, source = sock.recvfrom(256)
        except socket.timeout:
            print('timed out')
            return
        message_type, message_code, check, identifier, sequence_number = struct.unpack('bbHHh', data[:8])
        if source == (destination, 0) and message_type == ICMP.ECHO_REPLY and data[8:] == payload:
            print((time.time_ns() - start_time) // 1_000_000, 'ms')
            break
        else:
            print('got unexpected packet from %s:' % source[0], message_type, data[8:])
    else:
        print('timed out')

def encode(payload: bytes):
    # calculate checksum with check set to 0
    checksum = calc_checksum(icmp_header(ICMP.ECHO_REQUEST, 0, 0, 1, 1) + payload)
    # craft the packet again with the checksum set
    return icmp_header(ICMP.ECHO_REQUEST, 0, checksum, 1, 1) + payload

def icmp_header(message_type, message_code, check, identifier, sequence_number) -> bytes:
    return struct.pack('bbHHh', message_type, message_code, check, identifier, sequence_number)

def calc_checksum(data: bytes) -> int:
    '''RFC 1071'''
    # code stolen from https://github.com/alessandromaggio/pythonping/blob/a59ce65a/pythonping/icmp.py#L8
    '''
    MIT License

    Copyright (c) 2018 Alessandro Maggio

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
    '''
    subtotal = 0
    for i in range(0, len(data)-1, 2):
        subtotal += (data[i] << 8) + data[i+1]
    if len(data) % 2:
        subtotal += (data[len(data)-1] << 8)
    while subtotal >> 16:
        subtotal = (subtotal & 0xFFFF) + (subtotal >> 16)
    check = ~subtotal
    return ((check << 8) & 0xFF00) | ((check >> 8) & 0x00FF)

class ICMP:
    ECHO_REPLY = 0
    ECHO_REQUEST = 8

虽然这里其他答案建议的许多软件包也可以工作

使用python3中的套接字包:

import socket

def ping_server(server: str, port: int, timeout=3):
    """ping server"""
    try:
        socket.setdefaulttimeout(timeout)
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.connect((server, port))
    except OSError as error:
        return False
    else:
        s.close()
        return True

编程ICMP ping很复杂,因为发送原始ICMP包需要更高的权限,而且调用ping二进制很难看。对于服务器监控,您可以使用TCP ping技术实现相同的结果:

# pip3 install tcping
>>> from tcping import Ping
# Ping(host, port, timeout)
>>> ping = Ping('212.69.63.54', 22, 60)
>>> ping.ping(3)
Connected to 212.69.63.54[:22]: seq=1 time=23.71 ms
Connected to 212.69.63.54[:22]: seq=2 time=24.38 ms
Connected to 212.69.63.54[:22]: seq=3 time=24.00 ms

在内部,这只是建立一个到目标服务器的TCP连接,并立即丢弃它,测量所消耗的时间。这个特殊的实现有点局限,因为它不能处理封闭的端口,但对于您自己的服务器来说,它工作得很好。