coding: utf-8

import socket
import struct
import time

ICMP_ECHO_REQUEST = 8 # 设定Ping类型为8

def checksum(data):
n = len(data)
m = n % 2
sum = 0
for i in range(0, n - m, 2):
sum += ord(chr(data[i])) + (ord(chr(data[i + 1])) << 8)
if m:
sum += ord(data[-1])
sum = (sum >> 16) + (sum & 0xffff)
sum += (sum >> 16)
answer = ~sum & 0xffff
answer = answer >> 8 | (answer << 8 & 0xff00)
return answer

def receiveOnePing(mySocket, ID, timeout):
while 1:
timeReceived = time.time()
recPacket, addr = mySocket.recvfrom(1024)
header = recPacket[20: 28]
type, code, checksum, packetID, sequence = struct.unpack(“!bbHHh”, header)

    if type == 0 and packetID == ID:
        byte_in_double = struct.calcsize("!d")
        timeSent = struct.unpack("!d", recPacket[28: 28 + byte_in_double])[0]
        delay = timeReceived - timeSent
        ttl = ord(struct.unpack("!c", recPacket[8:9])[0].decode())
        if timeout <= delay:
            return None
        return delay, ttl, byte_in_double

def doOnePing(destAddr, ID, sequence, timeout):
# ********* Begin *********#
# 创建ICMP协议的socket对象
mySocket = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)
# ********* End *********#
myChecksum = 0
header = struct.pack(“!bbHHh”, ICMP_ECHO_REQUEST, 0, myChecksum, ID, sequence)
data = struct.pack(“!d”, time.time())
myChecksum = checksum(header + data)
header = struct.pack(“!bbHHh”, ICMP_ECHO_REQUEST, 0, myChecksum, ID, sequence)
packet = header + data
# ********* Begin *********#
# 生成校验和，并生成ping数据报
myChecksum = 0
header = struct.pack(“!bbHHh”, ICMP_ECHO_REQUEST, 0, myChecksum, ID, sequence)
data = struct.pack(“!d”, time.time())
myChecksum = checksum(header + data)
header = struct.pack(“!bbHHh”, ICMP_ECHO_REQUEST, 0, myChecksum, ID, sequence)
packet = header + data
# ********* End *********#

# ********* Begin *********#
# 发送该数据包
mySocket.sendto(packet, (destAddr, 12345))  
# ********* End *********#

ans = receiveOnePing(mySocket, ID, timeout)

# ********* Begin *********#
# 关闭socket对象
mySocket.close()  
# ********* End *********#

return ans

def ping(host, timeout=1):
# ********* Begin *********#
# 获取地址，并输出发送信息，参考预期输出的第一行
dest = socket.gethostbyname(host)
print(“Pinging " + dest + " using Python:”)
# ********* End *********#

myID = 2468
loss = 0  # 用来统计丢包数量
for i in range(5):
    result = doOnePing(dest, myID, i, timeout)

    # ********* Begin *********#
    # 如果没有收到pong报文，输出 Request timed out.  
    # 及时记录丢包数量  
    if not result:  
        print("Request timed out.")  
        loss += 1  
    # ********* End *********#

    # ********* Begin *********#
    # 收到pong报文，获取并输出相应的信息，具体输出格式参考预期输出
    else:  
        delay = int(result[0] * 1000)  
        ttl = result[1]  
        bytes = result[2]  
        print("Received from " + dest + ": byte(s)=" + str(bytes) + " delay=" + str(delay) + "ms TTL=" + str(ttl))  
    # ********* End *********#

    time.sleep(1)

# ********* Begin *********#
# 输出统计的信息，包括发送、接收以及丢失数据包的个数，具体输出格式参考预期输出
print("Packet: sent = " + str(5) + " received = " + str(5-loss) + " lost = " + str(loss))  
# ********* End *********#

return

ping(“localhost”)