[telemetry] Implement Forwarder using RNDIS.

tools/telemetry/telemetry/core/backends/android_rndis.py

Index: tools/telemetry/telemetry/core/backends/android_rndis.py
diff --git a/tools/telemetry/telemetry/core/backends/android_rndis.py b/tools/telemetry/telemetry/core/backends/android_rndis.py
new file mode 100644
index 0000000000000000000000000000000000000000..9d659533af075c3412aa8a2f1a9e6b64cadef452
--- /dev/null
+++ b/tools/telemetry/telemetry/core/backends/android_rndis.py
@@ -0,0 +1,341 @@
+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+import logging
+import os
+import re
+import socket
+import struct
+import subprocess
+import sys
+
+from telemetry.core.backends import adb_commands
+
+
+def _CheckOutput(*popenargs, **kwargs):
+  """Backport of subprocess.check_output to python 2.6"""
+  process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
+  output, _ = process.communicate()
+  retcode = process.poll()
+  if retcode:
+    cmd = kwargs.get('args')
+    if cmd is None:
+      cmd = popenargs[0]
+    error = subprocess.CalledProcessError(retcode, cmd)
+    error.output = output
+    raise error
+  return output
+
+
+class RndisForwarderWithRoot(object):
+  """Forwards traffic using RNDIS. Assuming the device has root access.
+  """
+  _RNDIS_DEVICE = '/sys/class/android_usb/android0'
+
+  def __init__(self, adb):
+    """Args:
+         adb: an instance of AdbCommands
+    """
+    assert adb.IsRootEnabled(), 'Root must be enabled to use RNDIS forwarding.'
+    self._adb = adb.Adb()
+
+    self._host_port = 80
+    self._host_ip = None
+    self._device_ip = None
+    self._host_iface = None
+    self._device_iface = None
+    self._original_dns = None, None, None
+
+    assert self._IsRndisSupported(), 'Device does not have rndis!'
+    self._CheckConfigureNetwork()
+
+  def SetPorts(self, *port_pairs):
+    """Args:
+         port_pairs: Used for compatibility with Forwarder. RNDIS does not
+           support mapping so local_port must match remote_port in all pairs.
+    """
+    assert all(pair.remote_port == pair.local_port for pair in port_pairs), \
+           'Local and remote ports must be the same on all pairs with RNDIS.'
+    self._host_port = port_pairs[0].local_port
+
+  def OverrideDns(self):
+    """Overrides DNS on device to point at the host."""
+    self._original_dns = self._GetCurrentDns()
+    self._OverrideDns(self._device_iface, self._host_ip, self._host_ip)
+
+  def _IsRndisSupported(self):
+    """Checks that the device has RNDIS support in the kernel."""
+    return self._adb.FileExistsOnDevice(
+        '%s/f_rndis/device' % self._RNDIS_DEVICE)
+
+  def _WaitForDevice(self):
+    self._adb.Adb().SendCommand('wait-for-device')
+
+  def _FindDeviceRndisInterface(self):
+    """Returns the name of the RNDIS network interface if present."""
+    config = self._adb.RunShellCommand('netcfg')
+    candidates = [line.split()[0] for line in config if 'rndis' in line]
+    if candidates:
+      assert len(candidates) == 1, 'Found more than one rndis device!'
+      return candidates[0]
+
+  def _EnumerateHostInterfaces(self):
+    if sys.platform.startswith('linux'):
+      return _CheckOutput(['ip', 'addr']).splitlines()
+    elif sys.platform == 'darwin':
+      return _CheckOutput(['ifconfig']).splitlines()
+    raise Exception('Platform %s not supported!' % sys.platform)
+
+  def _FindHostRndisInterface(self):
+    """Returns the name of the host-side network interface."""
+    interface_list = self._EnumerateHostInterfaces()
+    ether_address = self._adb.GetFileContents(
+        '%s/f_rndis/ethaddr' % self._RNDIS_DEVICE)[0]
+    interface_name = None
+    for line in interface_list:
+      if not line.startswith(' '):
+        interface_name = line.split()[1].strip(':')
+      elif ether_address in line:
+        return interface_name
+
+  def _DisableRndis(self):
+    self._adb.RunShellCommand('setprop sys.usb.config adb')
+    self._WaitForDevice()
+
+  def _EnableRndis(self):
+    """Enables the RNDIS network interface."""
+    script_prefix = '/data/local/tmp/rndis'
+    # This could be accomplished via "svc usb setFunction rndis" but only on
+    # devices which have the "USB tethering" feature.
+    # Also, on some devices, it's necessary to go through "none" function.
+    script = """
+trap '' HUP
+trap '' TERM
+trap '' PIPE
+
+function manual_config() {
+  echo %(functions)s > %(dev)s/functions
+  echo 224 > %(dev)s/bDeviceClass
+  echo 1 > %(dev)s/enable
+  start adbd
+  setprop sys.usb.state %(functions)s
+}
+
+# This function kills adb transport, so it has to be run "detached".
+function doit() {
+  setprop sys.usb.config none
+  while [ `getprop sys.usb.state` != "none" ]; do
+    sleep 1
+  done
+  manual_config
+  # For some combinations of devices and host kernels, adb won't work unless the
+  # interface is up, but if we bring it up immediately, it will break adb.
+  #sleep 1
+  #ifconfig rndis0 192.168.42.2 netmask 255.255.255.0 up
+  echo DONE >> %(prefix)s.log
+}
+
+doit &
+    """ % {'dev': self._RNDIS_DEVICE, 'functions': 'rndis,adb',
+           'prefix': script_prefix }
+    self._adb.SetFileContents('%s.sh' % script_prefix, script)
+    # TODO(szym): run via su -c if necessary.
+    self._adb.RunShellCommand('rm %s.log' % script_prefix)
+    self._adb.RunShellCommand('. %s.sh' % script_prefix)
+    self._WaitForDevice()
+    result = self._adb.GetFileContents('%s.log' % script_prefix)
+    assert any('DONE' in line for line in result), 'RNDIS script did not run!'
+
+  def _CheckEnableRndis(self, force):
+    """Enables the RNDIS network interface, retrying if necessary.
+    Args:
+      force: Disable RNDIS first, even if it appears already enabled.
+    Returns:
+      device_iface: RNDIS interface name on the device
+      host_iface: corresponding interface name on the host
+    """
+    for _ in range(3):
+      if not force:
+        device_iface = self._FindDeviceRndisInterface()
+        if device_iface:
+          host_iface = self._FindHostRndisInterface()
+          if host_iface:
+            return device_iface, host_iface
+      self._DisableRndis()
+      self._EnableRndis()
+      force = False
+    raise Exception('Could not enable RNDIS, giving up.')
+
+  def _GetHostAddresses(self, iface):
+    """Returns the IP addresses on host's interfaces, breaking out |iface|."""
+    interface_list = self._EnumerateHostInterfaces()
+    addresses = []
+    iface_address = None
+    found_iface = False
+    for line in interface_list:
+      if not line.startswith(' '):
+        found_iface = iface in line
+      match = re.search('(?<=inet )\S+', line)
+      if match:
+        address = match.group(0)
+        if found_iface:
+          assert not iface_address, (
+            'Found %s twice when parsing host interfaces.' % iface)
+          iface_address = address
+        else:
+          addresses.append(address)
+    return addresses, iface_address
+
+  def _GetDeviceAddresses(self, excluded_iface):
+    """Returns the IP addresses on all connected devices.
+    Excludes interface |excluded_iface| on the selected device.
+    """
+    my_device = self._adb.GetDevice()
+    addresses = []
+    for device in adb_commands.GetAttachedDevices():
+      adb = adb_commands.AdbCommands(device).Adb()
+      if device == my_device:
+        excluded = excluded_iface
+      else:
+        excluded = 'no interfaces excluded on other devices'
+      addresses += [line.split()[2] for line in adb.RunShellCommand('netcfg')
+                    if excluded not in line]
+    return addresses
+
+  def _ConfigureNetwork(self, device_iface, host_iface):
+    """Configures the |device_iface| to be on the same network as |host_iface|.
+    """
+    def _Ip2Long(addr):
+      return struct.unpack('!L', socket.inet_aton(addr))[0]
+
+    def _Long2Ip(value):
+      return socket.inet_ntoa(struct.pack('!L', value))
+
+    def _Length2Mask(length):
+      return 0xFFFFFFFF & ~((1 << (32 - length)) - 1)
+
+    def _IpPrefix2AddressMask(addr):
+      addr, masklen = addr.split('/')
+      return _Ip2Long(addr), _Length2Mask(int(masklen))
+
+    def _IsNetworkUnique(network, addresses):
+      return all((addr & mask != network & mask) for addr, mask in addresses)
+
+    def _NextUnusedAddress(network, netmask, used_addresses):
+      # Excludes '0' and broadcast.
+      for suffix in range(1, 0xFFFFFFFF & ~netmask):
+        candidate = network | suffix
+        if candidate not in used_addresses:
+          return candidate
+
+    addresses, host_address = self._GetHostAddresses(host_iface)
+
+    assert host_address, ('Interface %(iface)s was not configured.\n'
+      'To configure it automatically, add to /etc/network/interfaces:\n'
+      'auto %(iface)s\n'
+      'iface %(iface)s\n'
+      '  address 192.168.<unique>.1\n'
+      '  netmask 255.255.255.0' % {'iface': host_iface})
+
+    addresses = [_IpPrefix2AddressMask(addr) for addr in addresses]
+    host_ip, netmask = _IpPrefix2AddressMask(host_address)
+
+    network = host_ip & netmask
+
+    if not _IsNetworkUnique(network, addresses):
+      logging.warning(
+        'The IP address configuration %s of %s is not unique!\n'
+        'Check your /etc/network/interfaces. If this overlap is intended,\n'
+        'you might need to use: ip rule add from <device_ip> lookup <table>\n'
+        'or add the interface to a bridge in order to route to this network.'
+        % (host_address, host_iface)
+      )
+
+    # Find unused IP address.
+    used_addresses = [addr for addr, _ in addresses]
+    used_addresses += [_IpPrefix2AddressMask(addr)[0]
+                       for addr in self._GetDeviceAddresses(device_iface)]
+    used_addresses += [host_ip]
+
+    device_ip = _NextUnusedAddress(network, netmask, used_addresses)
+    assert device_ip, ('The network %s on %s is full.' %
+                       (host_address, host_iface))
+
+    host_ip = _Long2Ip(host_ip)
+    device_ip = _Long2Ip(device_ip)
+    netmask = _Long2Ip(netmask)
+
+    # TODO(szym) run via su -c if necessary.
+    self._adb.RunShellCommand('ifconfig %s %s netmask %s up' %
+                              (device_iface, device_ip, netmask))
+    # Enabling the interface sometimes breaks adb.
+    self._WaitForDevice()
+    self._host_iface = host_iface
+    self._host_ip = host_ip
+    self._device_iface = device_iface
+    self._device_ip = device_ip
+
+  def _TestConnectivity(self):
+    with open(os.devnull, 'wb') as devnull:
+      return subprocess.call(['ping', '-q', '-c1', '-W1',
+                              '-I', self._host_iface, self._device_ip],
+                              stdout=devnull) == 0
+
+  def _CheckConfigureNetwork(self):
+    """Enables RNDIS and configures it, retrying until we have connectivity."""
+    force = False
+    for _ in range(3):
+      device_iface, host_iface = self._CheckEnableRndis(force)
+      self._ConfigureNetwork(device_iface, host_iface)
+      if self._TestConnectivity():
+        return
+      force = True
+    raise Exception('No connectivity, giving up.')
+
+  def _GetCurrentDns(self):
+    """Returns current gateway, dns1, and dns2."""
+    routes = self._adb.RunShellCommand('cat /proc/net/route')[1:]
+    routes = [route.split() for route in routes]
+    default_routes = [route[0] for route in routes if route[1] == '00000000']
+    return (
+      default_routes[0] if default_routes else None,
+      self._adb.RunShellCommand('getprop net.dns1')[0],
+      self._adb.RunShellCommand('getprop net.dns2')[0],
+    )
+
+  def _OverrideDns(self, iface, dns1, dns2):
+    """Overrides device's DNS configuration.
+
+    Args:
+      iface: name of the network interface to make default
+      dns1, dns2: nameserver IP addresses
+    """
+    if not iface:
+      return  # If there is no route, then nobody cares about DNS.
+    # DNS proxy in older versions of Android is configured via properties.
+    # TODO(szym): run via su -c if necessary.
+    self._adb.RunShellCommand('setprop net.dns1 ' + dns1)
+    self._adb.RunShellCommand('setprop net.dns2 ' + dns2)
+    dnschange = self._adb.RunShellCommand('getprop net.dnschange')[0]
+    if dnschange:
+      self._adb.RunShellCommand('setprop net.dnschange %s' %
+                                (int(dnschange) + 1))
+    # Since commit 8b47b3601f82f299bb8c135af0639b72b67230e6 to frameworks/base
+    # the net.dns1 properties have been replaced with explicit commands for netd
+    self._adb.RunShellCommand('ndc netd resolver setifdns %s %s %s' %
+                              (iface, dns1, dns2))
+    # TODO(szym): if we know the package UID, we could setifaceforuidrange
+    self._adb.RunShellCommand('ndc netd resolver setdefaultif %s' % iface)
+
+  @property
+  def host_ip(self):
+    return self._host_ip
+
+  @property
+  def url(self):
+    # localhost and domains which resolve on the host's private network will not
+    # be resolved by the DNS proxy to the HTTP proxy.
+    return 'http://%s:%d' % (self._host_ip, self._host_port)
+
+  def Close(self):
+    self._OverrideDns(*self._original_dns)