python实现ping的方法

本文实例讲述了python实现ping的方法。分享给大家供大家参考。具体如下:

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#!/usr/bin/env python

#coding:utf-8

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

# From /usr/include/linux/icmp.h; your milage may vary.

ICMP_ECHO_REQUEST = 8 # Seems to be the same on Solaris.

def checksum(source_string):

"""

I'm not too confident that this is right but testing seems

to suggest that it gives the same answers as in_cksum in ping.c

"""

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 # Necessary?

count = count + 2

if countTo<len(source_string):

sum = sum + ord(source_string[len(source_string) - 1])

sum = sum & 0xffffffff # Necessary?

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

sum = sum + (sum >> 16)

answer = ~sum

answer = answer & 0xffff

# Swap bytes. Bugger me if I know why.

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

return answer

def receive_one_ping(my_socket, ID, timeout):

"""

receive the ping from the socket.

"""

timeLeft = timeout

while True:

startedSelect = time.time()

whatReady = select.select([my_socket], [], [], timeLeft)

howLongInSelect = (time.time() - startedSelect)

if whatReady[0] == []: # Timeout

return

timeReceived = time.time()

recPacket, addr = my_socket.recvfrom(1024)

icmpHeader = recPacket[20:28]

type, code, checksum, packetID, sequence = struct.unpack(

"bbHHh", icmpHeader

)

if packetID == ID:

bytesInDouble = struct.calcsize("d")

timeSent = struct.unpack("d", recPacket[28:28 + bytesInDouble])[0]

return timeReceived - timeSent

timeLeft = timeLeft - howLongInSelect

if timeLeft <= 0:

return

def send_one_ping(my_socket, dest_addr, ID):

"""

Send one ping to the given >dest_addr<.

"""

dest_addr = socket.gethostbyname(dest_addr)

# Header is type (8), code (8), checksum (16), id (16), sequence (16)

my_checksum = 0

# Make a dummy heder with a 0 checksum.

header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, my_checksum, ID, 1) #压包

#a1 = struct.unpack("bbHHh",header) #my test

bytesInDouble = struct.calcsize("d")

data = (192 - bytesInDouble) * "Q"

data = struct.pack("d", time.time()) + data

# Calculate the checksum on the data and the dummy header.

my_checksum = checksum(header + data)

# Now that we have the right checksum, we put that in. It's just easier

# to make up a new header than to stuff it into the dummy.

header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, socket.htons(my_checksum), ID, 1)

packet = header + data

my_socket.sendto(packet, (dest_addr, 1)) # Don't know about the 1

def do_one(dest_addr, timeout):

"""

Returns either the delay (in seconds) or none on timeout.

"""

icmp = socket.getprotobyname("icmp")

try:

my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)

except socket.error, (errno, msg):

if errno == 1:

# Operation not permitted

msg = msg + (

" - Note that ICMP messages can only be sent from processes"

" running as root."

)

raise socket.error(msg)

raise # raise the original error

my_ID = os.getpid() & 0xFFFF

send_one_ping(my_socket, dest_addr, my_ID)

delay = receive_one_ping(my_socket, my_ID, timeout)

my_socket.close()

return delay

def verbose_ping(dest_addr, timeout = 2, count = 100):

"""

Send >count< ping to >dest_addr< with the given >timeout< and display

the result.

"""

for i in xrange(count):

print "ping %s..." % dest_addr,

try:

delay = do_one(dest_addr, timeout)

except socket.gaierror, e:

print "failed. (socket error: '%s')" % e[1]

break

if delay == None:

print "failed. (timeout within %ssec.)" % timeout

else:

delay = delay * 1000

print "get ping in %0.4fms" % delay

if __name__ == '__main__':

verbose_ping("www.163.com",2,1)

希望本文所述对大家的Python程序设计有所帮助。

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