基于winpcap的网络抓包python程序

以下是一个基于WinPcap的网络抓包Python程序的示例代码：

import socket
import struct
import sys
import threading

from ctypes import *
from winpcapy import *


# define constants
PCAP_ERRBUF_SIZE = 256


# define structure for IP header
class IP(Structure):
    _fields_ = [
        ("ihl",             c_ubyte,    4),
        ("version",         c_ubyte,    4),
        ("tos",             c_ubyte),
        ("len",             c_ushort),
        ("id",              c_ushort),
        ("offset",          c_ushort),
        ("ttl",             c_ubyte),
        ("protocol_num",    c_ubyte),
        ("sum",             c_ushort),
        ("src",             c_ulong),
        ("dst",             c_ulong)
    ]

    def __new__(self, data=None):
        return self.from_buffer_copy(data)

    def __init__(self, data=None):
        # map protocol constants to their names
        self.protocol_map = {1: "ICMP", 6: "TCP", 17: "UDP"}

        # human readable IP addresses
        self.src_address = socket.inet_ntoa(struct.pack("<L", self.src))
        self.dst_address = socket.inet_ntoa(struct.pack("<L", self.dst))

        # human readable protocol
        try:
            self.protocol = self.protocol_map[self.protocol_num]
        except:
            self.protocol = str(self.protocol_num)


# define callback function for packet capture
def packet_handler(header, data):
    # parse IP header
    ip_header = IP(data)

    # print out packet information
    print("Protocol: %s, Source: %s, Destination: %s" % (ip_header.protocol, ip_header.src_address, ip_header.dst_address))


def main():
    # open network adapter for capturing
    errbuf = create_string_buffer(PCAP_ERRBUF_SIZE)
    adapter = pcap_open_live("eth0", 65536, 1, 1000, errbuf)

    if not adapter:
        print("Unable to open adapter: %s" % errbuf.value.decode("utf-8"))
        sys.exit(1)

    # start packet capture loop
    try:
        pcap_loop(adapter, -1, packet_handler, None)
    except KeyboardInterrupt:
        pass

    # close the adapter
    pcap_close(adapter)


if __name__ == "__main__":
    main()

这个程序使用WinPcap库来捕获网络数据包，并使用Python中的ctypes库来定义IP头的结构体。程序打开一个名为“eth0”的网络适配器，然后进入无限循环以捕获数据包。当用户按下Ctrl + C时，程序将退出循环并关闭适配器。程序还包括一个包处理程序回调函数，它将在每个捕获的数据包上运行，并打印有关该包的一些信息。