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| 1 #!/usr/bin/env python | |
| 2 # Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. | |
| 3 # | |
| 4 # Use of this source code is governed by a BSD-style license | |
| 5 # that can be found in the LICENSE file in the root of the source | |
| 6 # tree. An additional intellectual property rights grant can be found | |
| 7 # in the file PATENTS. All contributing project authors may | |
| 8 # be found in the AUTHORS file in the root of the source tree. | |
| 9 | |
| 10 """Script for constraining traffic on the local machine.""" | |
| 11 | |
| 12 import ctypes | |
| 13 import logging | |
| 14 import os | |
| 15 import subprocess | |
| 16 import sys | |
| 17 | |
| 18 | |
| 19 class NetworkEmulatorError(BaseException): | |
| 20 """Exception raised for errors in the network emulator. | |
| 21 | |
| 22 Attributes: | |
| 23 fail_msg: User defined error message. | |
| 24 cmd: Command for which the exception was raised. | |
| 25 returncode: Return code of running the command. | |
| 26 stdout: Output of running the command. | |
| 27 stderr: Error output of running the command. | |
| 28 """ | |
| 29 | |
| 30 def __init__(self, fail_msg, cmd=None, returncode=None, output=None, | |
| 31 error=None): | |
| 32 BaseException.__init__(self, fail_msg) | |
| 33 self.fail_msg = fail_msg | |
| 34 self.cmd = cmd | |
| 35 self.returncode = returncode | |
| 36 self.output = output | |
| 37 self.error = error | |
| 38 | |
| 39 | |
| 40 class NetworkEmulator(object): | |
| 41 """A network emulator that can constrain the network using Dummynet.""" | |
| 42 | |
| 43 def __init__(self, connection_config, port_range): | |
| 44 """Constructor. | |
| 45 | |
| 46 Args: | |
| 47 connection_config: A config.ConnectionConfig object containing the | |
| 48 characteristics for the connection to be emulation. | |
| 49 port_range: Tuple containing two integers defining the port range. | |
| 50 """ | |
| 51 self._pipe_counter = 0 | |
| 52 self._rule_counter = 0 | |
| 53 self._port_range = port_range | |
| 54 self._connection_config = connection_config | |
| 55 | |
| 56 def Emulate(self, target_ip): | |
| 57 """Starts a network emulation by setting up Dummynet rules. | |
| 58 | |
| 59 Args: | |
| 60 target_ip: The IP address of the interface that shall be that have the | |
| 61 network constraints applied to it. | |
| 62 """ | |
| 63 receive_pipe_id = self._CreateDummynetPipe( | |
| 64 self._connection_config.receive_bw_kbps, | |
| 65 self._connection_config.delay_ms, | |
| 66 self._connection_config.packet_loss_percent, | |
| 67 self._connection_config.queue_slots) | |
| 68 logging.debug('Created receive pipe: %s', receive_pipe_id) | |
| 69 send_pipe_id = self._CreateDummynetPipe( | |
| 70 self._connection_config.send_bw_kbps, | |
| 71 self._connection_config.delay_ms, | |
| 72 self._connection_config.packet_loss_percent, | |
| 73 self._connection_config.queue_slots) | |
| 74 logging.debug('Created send pipe: %s', send_pipe_id) | |
| 75 | |
| 76 # Adding the rules will start the emulation. | |
| 77 incoming_rule_id = self._CreateDummynetRule(receive_pipe_id, 'any', | |
| 78 target_ip, self._port_range) | |
| 79 logging.debug('Created incoming rule: %s', incoming_rule_id) | |
| 80 outgoing_rule_id = self._CreateDummynetRule(send_pipe_id, target_ip, | |
| 81 'any', self._port_range) | |
| 82 logging.debug('Created outgoing rule: %s', outgoing_rule_id) | |
| 83 | |
| 84 @staticmethod | |
| 85 def CheckPermissions(): | |
| 86 """Checks if permissions are available to run Dummynet commands. | |
| 87 | |
| 88 Raises: | |
| 89 NetworkEmulatorError: If permissions to run Dummynet commands are not | |
| 90 available. | |
| 91 """ | |
| 92 try: | |
| 93 if os.getuid() != 0: | |
| 94 raise NetworkEmulatorError('You must run this script with sudo.') | |
| 95 except AttributeError: | |
| 96 | |
| 97 # AttributeError will be raised on Windows. | |
| 98 if ctypes.windll.shell32.IsUserAnAdmin() == 0: | |
| 99 raise NetworkEmulatorError('You must run this script with administrator' | |
| 100 ' privileges.') | |
| 101 | |
| 102 def _CreateDummynetRule(self, pipe_id, from_address, to_address, | |
| 103 port_range): | |
| 104 """Creates a network emulation rule and returns its ID. | |
| 105 | |
| 106 Args: | |
| 107 pipe_id: integer ID of the pipe. | |
| 108 from_address: The IP address to match source address. May be an IP or | |
| 109 'any'. | |
| 110 to_address: The IP address to match destination address. May be an IP or | |
| 111 'any'. | |
| 112 port_range: The range of ports the rule shall be applied on. Must be | |
| 113 specified as a tuple of with two integers. | |
| 114 Returns: | |
| 115 The ID of the rule, starting at 100. The rule ID increments with 100 for | |
| 116 each rule being added. | |
| 117 """ | |
| 118 self._rule_counter += 100 | |
| 119 add_part = ['add', self._rule_counter, 'pipe', pipe_id, | |
| 120 'ip', 'from', from_address, 'to', to_address] | |
| 121 _RunIpfwCommand(add_part + ['src-port', '%s-%s' % port_range], | |
| 122 'Failed to add Dummynet src-port rule.') | |
| 123 _RunIpfwCommand(add_part + ['dst-port', '%s-%s' % port_range], | |
| 124 'Failed to add Dummynet dst-port rule.') | |
| 125 return self._rule_counter | |
| 126 | |
| 127 def _CreateDummynetPipe(self, bandwidth_kbps, delay_ms, packet_loss_percent, | |
| 128 queue_slots): | |
| 129 """Creates a Dummynet pipe and return its ID. | |
| 130 | |
| 131 Args: | |
| 132 bandwidth_kbps: Bandwidth. | |
| 133 delay_ms: Delay for a one-way trip of a packet. | |
| 134 packet_loss_percent: Float value of packet loss, in percent. | |
| 135 queue_slots: Size of the queue. | |
| 136 Returns: | |
| 137 The ID of the pipe, starting at 1. | |
| 138 """ | |
| 139 self._pipe_counter += 1 | |
| 140 cmd = ['pipe', self._pipe_counter, 'config', | |
| 141 'bw', str(bandwidth_kbps/8) + 'KByte/s', | |
| 142 'delay', '%sms' % delay_ms, | |
| 143 'plr', (packet_loss_percent/100.0), | |
| 144 'queue', queue_slots] | |
| 145 error_message = 'Failed to create Dummynet pipe. ' | |
| 146 if sys.platform.startswith('linux'): | |
| 147 error_message += ('Make sure you have loaded the ipfw_mod.ko module to ' | |
| 148 'your kernel (sudo insmod /path/to/ipfw_mod.ko).') | |
| 149 _RunIpfwCommand(cmd, error_message) | |
| 150 return self._pipe_counter | |
| 151 | |
| 152 def Cleanup(): | |
| 153 """Stops the network emulation by flushing all Dummynet rules. | |
| 154 | |
| 155 Notice that this will flush any rules that may have been created previously | |
| 156 before starting the emulation. | |
| 157 """ | |
| 158 _RunIpfwCommand(['-f', 'flush'], | |
| 159 'Failed to flush Dummynet rules!') | |
| 160 _RunIpfwCommand(['-f', 'pipe', 'flush'], | |
| 161 'Failed to flush Dummynet pipes!') | |
| 162 | |
| 163 def _RunIpfwCommand(command, fail_msg=None): | |
| 164 """Executes a command and prefixes the appropriate command for | |
| 165 Windows or Linux/UNIX. | |
| 166 | |
| 167 Args: | |
| 168 command: Command list to execute. | |
| 169 fail_msg: Message describing the error in case the command fails. | |
| 170 | |
| 171 Raises: | |
| 172 NetworkEmulatorError: If command fails a message is set by the fail_msg | |
| 173 parameter. | |
| 174 """ | |
| 175 if sys.platform == 'win32': | |
| 176 ipfw_command = ['ipfw.exe'] | |
| 177 else: | |
| 178 ipfw_command = ['sudo', '-n', 'ipfw'] | |
| 179 | |
| 180 cmd_list = ipfw_command[:] + [str(x) for x in command] | |
| 181 cmd_string = ' '.join(cmd_list) | |
| 182 logging.debug('Running command: %s', cmd_string) | |
| 183 process = subprocess.Popen(cmd_list, stdout=subprocess.PIPE, | |
| 184 stderr=subprocess.PIPE) | |
| 185 output, error = process.communicate() | |
| 186 if process.returncode != 0: | |
| 187 raise NetworkEmulatorError(fail_msg, cmd_string, process.returncode, output, | |
| 188 error) | |
| 189 return output.strip() | |
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Chromium Code Reviews
Issue 2864213004:
Rename tools-webrtc -> tools_webrtc (Closed)
