optimize_app_store_hosts.py

#!/usr/bin/env python
import sys,socket

PING_TIMEOUT = 1000
def main():
  hosts = ['a%d.phobos.apple.com' % i for i in range(1, 200)]
  ips = get_ips(hosts)
  records = ping_ips(ips)
  output(records)

def get_ips(hosts):
  ips = []
  for host in hosts:
    ips.extend(get_ip(host))
  return {}.fromkeys(ips).keys()

def get_ip(host):
  print 'Getting IP for %s' % host
  ip_records = socket.getaddrinfo(host, None, socket.AF_INET)
  return [ip_record[4][0] for ip_record in ip_records]

def ping_ips(ips):
  ping_result = [(ip, my_ping(ip)) for ip in ips]
  ping_result.sort(cmp=lambda x, y: cmp(x[1], y[1]))
  return ping_result

def output(records):
  record_lines = ['IP: %s\tTime: %f ms\n' % (record[0], round(record[1])) for record in records]
  write_file('apple_ip.txt', record_lines)
  if len(records) > 0 and records[0][1] < PING_TIMEOUT:
    ip = records[0][0]
    hosts_lines = ['%s\ta%d.phobos.apple.com\n' % (ip, i) for i in range(1, 2000)]
    hosts_lines.insert(0, "#START APPLE STORE#\n")
    hosts_lines.append("#END APPLE STORE#\n")
    write_file('hosts', hosts_lines)

def write_file(filename, lines):
  with open(filename, 'w') as output_file:
    output_file.writelines(lines)
  output_file.close()

def my_ping(hostname):
  return Ping(hostname, PING_TIMEOUT, 8).run(4)

# Following code is copied from https://github.com/jedie/python-ping/blob/master/ping.py
# I make some minor changes
"""
  A pure python ping implementation using raw sockets.

  Note that ICMP messages can only be send from processes running as root
  (in Windows, you must run this script as 'Administrator').

  Bugs are naturally mine. I'd be glad to hear about them. There are
  certainly word - size dependencies here.
  
  :homepage: https://github.com/jedie/python-ping/
  :copyleft: 1989-2011 by the python-ping team, see AUTHORS for more details.
  :license: GNU GPL v2, see LICENSE for more details.
"""


import os
import select
import signal
import socket
import struct
import sys
import time


if sys.platform.startswith("win32"):
  # On Windows, the best timer is time.clock()
  default_timer = time.clock
else:
  # On most other platforms the best timer is time.time()
  default_timer = time.time


# ICMP parameters
ICMP_ECHOREPLY = 0 # Echo reply (per RFC792)
ICMP_ECHO = 8 # Echo request (per RFC792)
ICMP_MAX_RECV = 2048 # Max size of incoming buffer

MAX_SLEEP = 1000


def calculate_checksum(source_string):
  """
  A port of the functionality of in_cksum() from ping.c
  Ideally this would act on the string as a series of 16-bit ints (host
  packed), but this works.
  Network data is big-endian, hosts are typically little-endian
  """
  countTo = (int(len(source_string) / 2)) * 2
  sum = 0
  count = 0

  # Handle bytes in pairs (decoding as short ints)
  loByte = 0
  hiByte = 0
  while count < countTo:
    if (sys.byteorder == "little"):
      loByte = source_string[count]
      hiByte = source_string[count + 1]
    else:
      loByte = source_string[count + 1]
      hiByte = source_string[count]
    sum = sum + (ord(hiByte) * 256 + ord(loByte))
    count += 2

  # Handle last byte if applicable (odd-number of bytes)
  # Endianness should be irrelevant in this case
  if countTo < len(source_string): # Check for odd length
    loByte = source_string[len(source_string) - 1]
    sum += ord(loByte)

  sum &= 0xffffffff # Truncate sum to 32 bits (a variance from ping.c, which
            # uses signed ints, but overflow is unlikely in ping)

  sum = (sum >> 16) + (sum & 0xffff)  # Add high 16 bits to low 16 bits
  sum += (sum >> 16)          # Add carry from above (if any)
  answer = ~sum & 0xffff        # Invert and truncate to 16 bits
  answer = socket.htons(answer)

  return answer


def is_valid_ip4_address(addr):
  parts = addr.split(".")
  if not len(parts) == 4:
    return False
  for part in parts:
    try:
      number = int(part)
    except ValueError:
      return False
    if number > 255:
      return False
  return True

def to_ip(addr):
  if is_valid_ip4_address(addr):
    return addr
  return socket.gethostbyname(addr)


class Ping(object):
  def __init__(self, destination, timeout=1000, packet_size=55, own_id=None):
    self.destination = destination
    self.timeout = timeout
    self.packet_size = packet_size
    if own_id is None:
      self.own_id = os.getpid() & 0xFFFF
    else:
      self.own_id = own_id

    try:
      # FIXME: Use destination only for display this line here? see: https://github.com/jedie/python-ping/issues/3
      self.dest_ip = to_ip(self.destination)
    except socket.gaierror as e:
      self.print_unknown_host(e)
    else:
      self.print_start()

    self.seq_number = 0
    self.send_count = 0
    self.receive_count = 0
    self.min_time = 999999999
    self.max_time = 0.0
    self.total_time = 0.0

  #--------------------------------------------------------------------------

  def print_start(self):
    print("\nPYTHON-PING %s (%s): %d data bytes" % (self.destination, self.dest_ip, self.packet_size))

  def print_unknown_host(self, e):
    print("\nPYTHON-PING: Unknown host: %s (%s)\n" % (self.destination, e.args[1]))

  def print_success(self, delay, ip, packet_size, ip_header, icmp_header):
    if ip == self.destination:
      from_info = ip
    else:
      from_info = "%s (%s)" % (self.destination, ip)

    print("%d bytes from %s: icmp_seq=%d ttl=%d time=%.1f ms" % (
      packet_size, from_info, icmp_header["seq_number"], ip_header["ttl"], delay)
    )
    #print("IP header: %r" % ip_header)
    #print("ICMP header: %r" % icmp_header)

  def print_failed(self):
    print("Request timed out.")

  def print_exit(self):
    print("\n----%s PYTHON PING Statistics----" % (self.destination))

    lost_count = self.send_count - self.receive_count
    #print("%i packets lost" % lost_count)
    lost_rate = float(lost_count) / self.send_count * 100.0

    print("%d packets transmitted, %d packets received, %0.1f%% packet loss" % (
      self.send_count, self.receive_count, lost_rate
    ))

    if self.receive_count > 0:
      print("round-trip (ms)  min/avg/max = %0.3f/%0.3f/%0.3f" % (
        self.min_time, self.total_time / self.receive_count, self.max_time
      ))

    print("")

  #--------------------------------------------------------------------------

  def signal_handler(self, signum, frame):
    """
    Handle print_exit via signals
    """
    self.print_exit()
    print("\n(Terminated with signal %d)\n" % (signum))
    sys.exit(0)

  def setup_signal_handler(self):
    signal.signal(signal.SIGINT, self.signal_handler)   # Handle Ctrl-C
    if hasattr(signal, "SIGBREAK"):
      # Handle Ctrl-Break e.g. under Windows 
      signal.signal(signal.SIGBREAK, self.signal_handler)

  #--------------------------------------------------------------------------

  def header2dict(self, names, struct_format, data):
    """ unpack the raw received IP and ICMP header informations to a dict """
    unpacked_data = struct.unpack(struct_format, data)
    return dict(zip(names, unpacked_data))

  #--------------------------------------------------------------------------

  def run(self, count=None, deadline=None):
    """
    send and receive pings in a loop. Stop if count or until deadline.
    """
    self.setup_signal_handler()

    while True:
      delay = self.do()

      self.seq_number += 1
      if count and self.seq_number >= count:
        break
      if deadline and self.total_time >= deadline:
        break

      if delay == None:
        delay = 0

      # Pause for the remainder of the MAX_SLEEP period (if applicable)
      if (MAX_SLEEP > delay):
        time.sleep((MAX_SLEEP - delay) / 1000.0)

    #self.print_exit()
    if self.receive_count == 0:
      return self.timeout
    else:
      return self.total_time / self.receive_count

  def do(self):
    """
    Send one ICMP ECHO_REQUEST and receive the response until self.timeout
    """
    try: # One could use UDP here, but it's obscure
      current_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.getprotobyname("icmp"))
    except socket.error, (errno, msg):
      if errno == 1:
        # Operation not permitted - Add more information to traceback
        etype, evalue, etb = sys.exc_info()
        evalue = etype(
          "%s - Note that ICMP messages can only be send from processes running as root." % evalue
        )
        raise etype, evalue, etb
      raise # raise the original error

    send_time = self.send_one_ping(current_socket)
    if send_time == None:
      return
    self.send_count += 1

    receive_time, packet_size, ip, ip_header, icmp_header = self.receive_one_ping(current_socket)
    current_socket.close()

    if receive_time:
      self.receive_count += 1
      delay = (receive_time - send_time) * 1000.0
      self.total_time += delay
      if self.min_time > delay:
        self.min_time = delay
      if self.max_time < delay:
        self.max_time = delay

      self.print_success(delay, ip, packet_size, ip_header, icmp_header)
      return delay
    else:
      self.print_failed()

  def send_one_ping(self, current_socket):
    """
    Send one ICMP ECHO_REQUEST
    """
    # Header is type (8), code (8), checksum (16), id (16), sequence (16)
    checksum = 0

    # Make a dummy header with a 0 checksum.
    header = struct.pack(
      "!BBHHH", ICMP_ECHO, 0, checksum, self.own_id, self.seq_number
    )

    padBytes = []
    startVal = 0x42
    for i in range(startVal, startVal + (self.packet_size)):
      padBytes += [(i & 0xff)]  # Keep chars in the 0-255 range
    data = bytes(padBytes)

    # Calculate the checksum on the data and the dummy header.
    checksum = calculate_checksum(header + data) # Checksum is in network order

    # 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, 0, checksum, self.own_id, self.seq_number
    )

    packet = header + data

    send_time = default_timer()

    try:
      current_socket.sendto(packet, (self.destination, 1)) # Port number is irrelevant for ICMP
    except socket.error as e:
      print("General failure (%s)" % (e.args[1]))
      current_socket.close()
      return

    return send_time

  def receive_one_ping(self, current_socket):
    """
    Receive the ping from the socket. timeout = in ms
    """
    timeout = self.timeout / 1000.0

    while True: # Loop while waiting for packet or timeout
      select_start = default_timer()
      inputready, outputready, exceptready = select.select([current_socket], [], [], timeout)
      select_duration = (default_timer() - select_start)
      if inputready == []: # timeout
        return None, 0, 0, 0, 0

      receive_time = default_timer()

      packet_data, address = current_socket.recvfrom(ICMP_MAX_RECV)

      icmp_header = self.header2dict(
        names=[
          "type", "code", "checksum",
          "packet_id", "seq_number"
        ],
        struct_format="!BBHHH",
        data=packet_data[20:28]
      )

      if icmp_header["packet_id"] == self.own_id: # Our packet
        ip_header = self.header2dict(
          names=[
            "version", "type", "length",
            "id", "flags", "ttl", "protocol",
            "checksum", "src_ip", "dest_ip"
          ],
          struct_format="!BBHHHBBHII",
          data=packet_data[:20]
        )
        packet_size = len(packet_data) - 28
        ip = socket.inet_ntoa(struct.pack("!I", ip_header["src_ip"]))
        # XXX: Why not ip = address[0] ???
        return receive_time, packet_size, ip, ip_header, icmp_header

      timeout = timeout - select_duration
      if timeout <= 0:
        return None, 0, 0, 0, 0

if __name__ == '__main__':
  main()