media/webrtc/trunk/build/android/pylib/fake_dns.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import android_commands
   6 import constants
   7 import logging
   8 import os
   9 import subprocess
  10 import time
  11
  12
  13 class FakeDns(object):
  14   """Wrapper class for the fake_dns tool."""
  15   _FAKE_DNS_PATH = '/data/local/tmp/fake_dns'
  16
  17   def __init__(self, adb, build_type):
  18     """
  19       Args:
  20         adb: the AndroidCommands to use.
  21         build_type: 'Release' or 'Debug'.
  22     """
  23     self._adb = adb
  24     self._build_type = build_type
  25     self._fake_dns = None
  26     self._original_dns = None
  27
  28   def _PushAndStartFakeDns(self):
  29     """Starts the fake_dns server that replies all name queries 127.0.0.1.
  30
  31     Returns:
  32       subprocess instance connected to the fake_dns process on the device.
  33     """
  34     self._adb.PushIfNeeded(
  35         os.path.join(constants.CHROME_DIR, 'out', self._build_type, 'fake_dns'),
  36         FakeDns._FAKE_DNS_PATH)
  37     return subprocess.Popen(
  38         ['adb', '-s', self._adb._adb.GetSerialNumber(),
  39          'shell', '%s -D' % FakeDns._FAKE_DNS_PATH])
  40
  41   def SetUp(self):
  42     """Configures the system to point to a DNS server that replies 127.0.0.1.
  43
  44     This can be used in combination with the forwarder to forward all web
  45     traffic to a replay server.
  46
  47     The TearDown() method will perform all cleanup.
  48     """
  49     self._adb.RunShellCommand('ip route add 8.8.8.0/24 via 127.0.0.1 dev lo')
  50     self._fake_dns = self._PushAndStartFakeDns()
  51     self._original_dns = self._adb.RunShellCommand('getprop net.dns1')[0]
  52     self._adb.RunShellCommand('setprop net.dns1 127.0.0.1')
  53     time.sleep(2)  # Time for server to start and the setprop to take effect.
  54
  55   def TearDown(self):
  56     """Shuts down the fake_dns."""
  57     if self._fake_dns:
  58       if not self._original_dns or self._original_dns == '127.0.0.1':
  59         logging.warning('Bad original DNS, falling back to Google DNS.')
  60         self._original_dns = '8.8.8.8'
  61       self._adb.RunShellCommand('setprop net.dns1 %s' % self._original_dns)
  62       self._fake_dns.kill()
  63       self._adb.RunShellCommand('ip route del 8.8.8.0/24 via 127.0.0.1 dev lo')