python实现ping的方法

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

#!/usr/bin/env Python#coding:utf-8import 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 answerdef 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:      returndef 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 1def 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 delaydef 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" % delayif __name__ == '__main__':  verbose_ping("www.163.com",2,1)

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