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Diffstat (limited to 'third_party/libwebrtc/tools_webrtc/network_emulator/network_emulator.py')
| -rw-r--r-- | third_party/libwebrtc/tools_webrtc/network_emulator/network_emulator.py | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/third_party/libwebrtc/tools_webrtc/network_emulator/network_emulator.py b/third_party/libwebrtc/tools_webrtc/network_emulator/network_emulator.py new file mode 100644 index 0000000000..a7776a5f92 --- /dev/null +++ b/third_party/libwebrtc/tools_webrtc/network_emulator/network_emulator.py @@ -0,0 +1,195 @@ +#!/usr/bin/env vpython3 + +# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. +# +# Use of this source code is governed by a BSD-style license +# that can be found in the LICENSE file in the root of the source +# tree. An additional intellectual property rights grant can be found +# in the file PATENTS. All contributing project authors may +# be found in the AUTHORS file in the root of the source tree. +"""Script for constraining traffic on the local machine.""" + +import ctypes +import logging +import os +import subprocess +import sys + + +class NetworkEmulatorError(BaseException): + """Exception raised for errors in the network emulator. + + Attributes: + fail_msg: User defined error message. + cmd: Command for which the exception was raised. + returncode: Return code of running the command. + stdout: Output of running the command. + stderr: Error output of running the command. + """ + + def __init__(self, + fail_msg, + cmd=None, + returncode=None, + output=None, + error=None): + BaseException.__init__(self, fail_msg) + self.fail_msg = fail_msg + self.cmd = cmd + self.returncode = returncode + self.output = output + self.error = error + + +class NetworkEmulator: + """A network emulator that can constrain the network using Dummynet.""" + + def __init__(self, connection_config, port_range): + """Constructor. + + Args: + connection_config: A config.ConnectionConfig object containing the + characteristics for the connection to be emulation. + port_range: Tuple containing two integers defining the port range. + """ + self._pipe_counter = 0 + self._rule_counter = 0 + self._port_range = port_range + self._connection_config = connection_config + + def Emulate(self, target_ip): + """Starts a network emulation by setting up Dummynet rules. + + Args: + target_ip: The IP address of the interface that shall be that have the + network constraints applied to it. + """ + receive_pipe_id = self._CreateDummynetPipe( + self._connection_config.receive_bw_kbps, + self._connection_config.delay_ms, + self._connection_config.packet_loss_percent, + self._connection_config.queue_slots) + logging.debug('Created receive pipe: %s', receive_pipe_id) + send_pipe_id = self._CreateDummynetPipe( + self._connection_config.send_bw_kbps, self._connection_config.delay_ms, + self._connection_config.packet_loss_percent, + self._connection_config.queue_slots) + logging.debug('Created send pipe: %s', send_pipe_id) + + # Adding the rules will start the emulation. + incoming_rule_id = self._CreateDummynetRule(receive_pipe_id, 'any', + target_ip, self._port_range) + logging.debug('Created incoming rule: %s', incoming_rule_id) + outgoing_rule_id = self._CreateDummynetRule(send_pipe_id, target_ip, 'any', + self._port_range) + logging.debug('Created outgoing rule: %s', outgoing_rule_id) + + @staticmethod + def CheckPermissions(): + """Checks if permissions are available to run Dummynet commands. + + Raises: + NetworkEmulatorError: If permissions to run Dummynet commands are not + available. + """ + try: + if os.getuid() != 0: + raise NetworkEmulatorError('You must run this script with sudo.') + except AttributeError as permission_error: + + # AttributeError will be raised on Windows. + if ctypes.windll.shell32.IsUserAnAdmin() == 0: + raise NetworkEmulatorError('You must run this script with administrator' + ' privileges.') from permission_error + + def _CreateDummynetRule(self, pipe_id, from_address, to_address, port_range): + """Creates a network emulation rule and returns its ID. + + Args: + pipe_id: integer ID of the pipe. + from_address: The IP address to match source address. May be an IP or + 'any'. + to_address: The IP address to match destination address. May be an IP or + 'any'. + port_range: The range of ports the rule shall be applied on. Must be + specified as a tuple of with two integers. + Returns: + The ID of the rule, starting at 100. The rule ID increments with 100 for + each rule being added. + """ + self._rule_counter += 100 + add_part = [ + 'add', self._rule_counter, 'pipe', pipe_id, 'ip', 'from', from_address, + 'to', to_address + ] + _RunIpfwCommand(add_part + ['src-port', '%s-%s' % port_range], + 'Failed to add Dummynet src-port rule.') + _RunIpfwCommand(add_part + ['dst-port', '%s-%s' % port_range], + 'Failed to add Dummynet dst-port rule.') + return self._rule_counter + + def _CreateDummynetPipe(self, bandwidth_kbps, delay_ms, packet_loss_percent, + queue_slots): + """Creates a Dummynet pipe and return its ID. + + Args: + bandwidth_kbps: Bandwidth. + delay_ms: Delay for a one-way trip of a packet. + packet_loss_percent: Float value of packet loss, in percent. + queue_slots: Size of the queue. + Returns: + The ID of the pipe, starting at 1. + """ + self._pipe_counter += 1 + cmd = [ + 'pipe', self._pipe_counter, 'config', 'bw', + str(bandwidth_kbps / 8) + 'KByte/s', 'delay', + '%sms' % delay_ms, 'plr', (packet_loss_percent / 100.0), 'queue', + queue_slots + ] + error_message = 'Failed to create Dummynet pipe. ' + if sys.platform.startswith('linux'): + error_message += ('Make sure you have loaded the ipfw_mod.ko module to ' + 'your kernel (sudo insmod /path/to/ipfw_mod.ko).') + _RunIpfwCommand(cmd, error_message) + return self._pipe_counter + + +def Cleanup(): + """Stops the network emulation by flushing all Dummynet rules. + + Notice that this will flush any rules that may have been created previously + before starting the emulation. + """ + _RunIpfwCommand(['-f', 'flush'], 'Failed to flush Dummynet rules!') + _RunIpfwCommand(['-f', 'pipe', 'flush'], 'Failed to flush Dummynet pipes!') + + +def _RunIpfwCommand(command, fail_msg=None): + """Executes a command and prefixes the appropriate command for + Windows or Linux/UNIX. + + Args: + command: Command list to execute. + fail_msg: Message describing the error in case the command fails. + + Raises: + NetworkEmulatorError: If command fails a message is set by the fail_msg + parameter. + """ + if sys.platform == 'win32': + ipfw_command = ['ipfw.exe'] + else: + ipfw_command = ['sudo', '-n', 'ipfw'] + + cmd_list = ipfw_command[:] + [str(x) for x in command] + cmd_string = ' '.join(cmd_list) + logging.debug('Running command: %s', cmd_string) + process = subprocess.Popen(cmd_list, + stdout=subprocess.PIPE, + stderr=subprocess.PIPE) + output, error = process.communicate() + if process.returncode != 0: + raise NetworkEmulatorError(fail_msg, cmd_string, process.returncode, output, + error) + return output.strip() |