python实现ping的方法

#!/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,my_checksum,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",socket.htons(my_checksum),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,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)