继上一篇计算checksum校验和，本章通过socket套接字，struct字节打包成二进制，select返回套接字的文件描述符的结合，实现一个简单的ping工具。
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#!/usr/bin/python3.6.4#!coding:utf-8__author__ = 'Rosefinch'__date__ = '2018/5/31 22:27'import timeimport structimport socketimport selectimport sysdef chesksum(data): """ 校验 """ n = len(data) m = n % 2 sum = 0 for i in range(0, n - m ,2): sum += (data[i]) + ((data[i+1]) << 8)#传入data以每两个字节（十六进制）通过ord转十进制，第一字节在低位，第二个字节在高位 if m: sum += (data[-1]) #将高于16位与低16位相加 sum = (sum >> 16) + (sum & 0xffff) sum += (sum >> 16) #如果还有高于16位，将继续与低16位相加 answer = ~sum & 0xffff #主机字节序转网络字节序列（参考小端序转大端序） answer = answer >> 8 | (answer << 8 & 0xff00) return answer ''' 连接套接字,并将数据发送到套接字 '''def raw_socket(dst_addr,imcp_packet): rawsocket = socket.socket(socket.AF_INET,socket.SOCK_RAW,socket.getprotobyname("icmp")) send_request_ping_time = time.time() #send data to the socket rawsocket.sendto(imcp_packet,(dst_addr,80)) return send_request_ping_time,rawsocket,dst_addr ''' request ping '''def request_ping(data_type,data_code,data_checksum,data_ID,data_Sequence,payload_body): #把字节打包成二进制数据 imcp_packet = struct.pack('>BBHHH32s',data_type,data_code,data_checksum,data_ID,data_Sequence,payload_body) icmp_chesksum = chesksum(imcp_packet)#获取校验和 imcp_packet = struct.pack('>BBHHH32s',data_type,data_code,icmp_chesksum,data_ID,data_Sequence,payload_body) return imcp_packet ''' reply ping '''def reply_ping(send_request_ping_time,rawsocket,data_Sequence,timeout = 2): while True: started_select = time.time() what_ready = select.select([rawsocket], [], [], timeout) wait_for_time = (time.time() - started_select) if what_ready[0] == []: # Timeout return -1 time_received = time.time() received_packet, addr = rawsocket.recvfrom(1024) icmpHeader = received_packet[20:28] type, code, checksum, packet_id, sequence = struct.unpack( ">BBHHH", icmpHeader ) if type == 0 and sequence == data_Sequence: return time_received - send_request_ping_time timeout = timeout - wait_for_time if timeout <= 0: return -1 ''' 实现 ping 主机/ip '''def ping(host): data_type = 8 # ICMP Echo Request data_code = 0 # must be zero data_checksum = 0 # "...with value 0 substituted for this field..." data_ID = 0 #Identifier data_Sequence = 1 #Sequence number payload_body = b'abcdefghijklmnopqrstuvwabcdefghi' #data dst_addr = socket.gethostbyname(host)#将主机名转ipv4地址格式，返回以ipv4地址格式的字符串，如果主机名称是ipv4地址，则它将保持不变 print("正在 Ping {0} [{1}] 具有 32 字节的数据:".format(host,dst_addr)) for i in range(0,4): icmp_packet = request_ping(data_type,data_code,data_checksum,data_ID,data_Sequence + i,payload_body) send_request_ping_time,rawsocket,addr = raw_socket(dst_addr,icmp_packet) times = reply_ping(send_request_ping_time,rawsocket,data_Sequence + i) if times > 0: print("来自 {0} 的回复: 字节=32 时间={1}ms".format(addr,int(times*1000))) time.sleep(0.7) else: print("请求超时。")if __name__ == "__main__": if len(sys.argv) < 2: sys.exit('Usage: ping.py <host>') ping(sys.argv[1]) |
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>python .\Ping_tool.py www.csdn.net正在 Ping www.csdn.net [47.95.164.112] 具有 32 字节的数据:来自 47.95.164.112 的回复: 字节=32 时间=39ms来自 47.95.164.112 的回复: 字节=32 时间=40ms来自 47.95.164.112 的回复: 字节=32 时间=40ms来自 47.95.164.112 的回复: 字节=32 时间=39ms |
引用：
https://docs.python.org/3/library/socket.html
https://docs.python.org/3/library/select.html#select.select
https://docs.python.org/3/library/struct.html
以上这篇python实现一个简单的ping工具方法就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/zhj082/article/details/80531628
