#!/usr/bin/python  
# -*- coding:utf-8 _*-
""" 
@author: pengtao 
@file: mping.py 
@time: 2020/03/26
"""

import os
import socket
import struct
import array


class Pinger(object):
    def __init__(self, timeout=3):
        self.timeout = timeout
        self.__id = os.getpid()
        self.__data = struct.pack('h', 1)  # h代表2个字节与头部8个字节组成偶数可进行最短校验

    @property
    def __icmpSocket(self):  # 返回一个可以利用的icmp原对象,当做属性使用
        icmp = socket.getprotobyname("icmp")  # 指定服务
        sock = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)  # socket.SOCK_RAW原生包
        return sock


    def __doCksum(self, packet):  # 校验和运算
        words = array.array('h', packet)  # 将包分割成2个字节为一组的网络序列
        sum = 0
        for word in words:
            sum += (word & 0xffff)  # 每2个字节相加
        sum = (sum >> 16) + (sum & 0xffff)  # 因为sum有可能溢出16位所以将最高位和低位sum相加重复二遍
        sum += (sum >> 16)  # 为什么这里的sum不需要再 & 0xffff 因为这里的sum已经是16位的不会溢出,可以手动测试超过65535的十进制数字就溢出了
        return (~sum) & 0xffff  # 最后取反返回完成校验

    @property
    def __icmpPacket(self):  # icmp包的构造
        header = struct.pack('bbHHh', 8, 0, 0, self.__id, 0)
        packet = header + self.__data
        cksum = self.__doCksum(packet)
        header = struct.pack('bbHHh', 8, 0, cksum, self.__id, 0)  # 将校验带入原有包,这里才组成头部,数据部分只是用来做校验所以返回的时候需要返回头部和数据相加
        return header + self.__data


    def sendPing(self, target_host):

        try:
            socket.gethostbyname(target_host)

            sock = self.__icmpSocket
            sock.settimeout(self.timeout)

            packet = self.__icmpPacket

            sock.sendto(packet, (target_host, 1))  # 发送icmp包

            ac_ip = sock.recvfrom(1024)[1][0]
            print('[+] %s active' % (ac_ip))
        except Exception:
            sock.close()
            return False
        return True


def main():
    pp = Pinger()
    pp.sendPing('192.168.100.20')


if __name__ == '__main__':
    main()