使用Python发送ping包

本文将从多个方面详细阐述如何使用Python发送ping包。

一、ping包简介

在计算机网络中，Ping（Packet Internet Groper）是一种用于测试网络连接速度的常用工具，通过向目标主机发送ICMP（Internet Control Message Protocol）回应请求来检测网络连接。Ping包发送到目标主机后，目标主机会返回一个ICMP回应包，表示目标主机能否正常接收和处理请求。

在Python中，我们可以使用socket库和icmp协议来手动发送和接收ping包。

二、发送ping包

Python通过socket库提供了发送和接收ICMP报文的接口，通过创建原始套接字进行操作。下面是一个使用Python发送ping包的示例代码：

import os
import sys
import struct
import socket
import select
import time

def checksum(source_string):
    sum = 0
    countTo = (len(source_string) / 2) * 2
    count = 0
    while count < countTo:
        thisVal = ord(source_string[count + 1]) * 256 + ord(source_string[count])
        sum = sum + thisVal
        sum = sum & 0xffffffff
        count = count + 2

    if countTo < len(source_string):
        sum = sum + ord(source_string[len(source_string) - 1])
        sum = sum & 0xffffffff

    sum = (sum >> 16) + (sum & 0xffff)
    sum = sum + (sum >> 16)
    answer = ~sum
    answer = answer & 0xffff

    answer = answer >> 8 | (answer << 8 & 0xff00)

    return answer

def send_ping():
    dest_addr = socket.gethostbyname('www.google.com')
    icmp = socket.getprotobyname("icmp")
    my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)
    my_id = os.getpid() & 0xFFFF

    sent_time = time.time()

    payload = struct.pack("d", sent_time)

    packet_checksum = checksum(struct.pack("bbHHhd", 8, 0, 0, my_id, 1, payload))

    packet = struct.pack("bbHHhd", 8, 0, packet_checksum, my_id, 1, payload)

    my_socket.sendto(packet, (dest_addr, 1))

    ping_data, addr = my_socket.recvfrom(1024)

    received_time = time.time()

    total_time = received_time - sent_time

    print('Ping %s (%s) took %fs' % (socket.gethostbyname('www.google.com'), addr[0], total_time))

    my_socket.close()

if __name__ == '__main__':
    send_ping()

三、解析ping包

在发送ping包后，我们可以通过解析ICMP回应包来获取一些关键信息，比如回应时间等。下面是一个使用Python解析ping包的示例代码：

import os
import sys
import struct
import socket
import select
import time

def unpack_ping(packet):
    icmp_header = packet[20:28]
    type, code, checksum, id, sequence, timestamp = struct.unpack("bbHHhd", icmp_header)
    return timestamp

def send_ping():
    dest_addr = socket.gethostbyname('www.google.com')
    icmp = socket.getprotobyname("icmp")
    my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)
    my_id = os.getpid() & 0xFFFF

    sent_time = time.time()

    payload = struct.pack("d", sent_time)

    packet_checksum = checksum(struct.pack("bbHHhd", 8, 0, 0, my_id, 1, payload))

    packet = struct.pack("bbHHhd", 8, 0, packet_checksum, my_id, 1, payload)

    my_socket.sendto(packet, (dest_addr, 1))

    ping_data, addr = my_socket.recvfrom(1024)

    received_time = time.time()

    total_time = received_time - sent_time

    print('Ping %s (%s) took %fs' % (socket.gethostbyname('www.google.com'), addr[0], total_time))

    timestamp = unpack_ping(ping_data)

    print('Timestamp: %f' % timestamp)

    my_socket.close()

if __name__ == '__main__':
    send_ping()

四、总结

通过本文的介绍，我们了解了使用Python发送ping包的方法，并通过示例代码演示了发送和解析ping包的过程。通过发送ping包，我们可以测试网络连接的速度和稳定性，以及计算网络延迟等关键指标，对于网络应用的开发和调试非常有帮助。