| # Copyright (c) 2013 The Chromium OS 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 collections |
| import logging |
| import os.path |
| import time |
| import uuid |
| |
| from autotest_lib.client.bin import utils |
| from autotest_lib.client.common_lib import error |
| from autotest_lib.client.common_lib.cros import path_utils |
| |
| |
| class PacketCapturesDisabledError(Exception): |
| """Signifies that this remote host does not support packet captures.""" |
| pass |
| |
| |
| # local_pcap_path refers to the path of the result on the local host. |
| # local_log_path refers to the tcpdump log file path on the local host. |
| CaptureResult = collections.namedtuple('CaptureResult', |
| ['local_pcap_path', 'local_log_path']) |
| |
| # The number of bytes needed for a probe request is hard to define, |
| # because the frame contents are variable (e.g. radiotap header may |
| # contain different fields, maybe SSID isn't the first tagged |
| # parameter?). The value here is 2x the largest frame size observed in |
| # a quick sample. |
| SNAPLEN_WIFI_PROBE_REQUEST = 600 |
| |
| TCPDUMP_START_TIMEOUT_SECONDS = 5 |
| TCPDUMP_START_POLL_SECONDS = 0.1 |
| |
| def get_packet_capturer(host, host_description=None, cmd_ifconfig=None, |
| cmd_ip=None, cmd_iw=None, cmd_netdump=None, |
| ignore_failures=False): |
| cmd_ifconfig = (cmd_ifconfig or |
| path_utils.get_install_path('ifconfig', host=host)) |
| cmd_iw = cmd_iw or path_utils.get_install_path('iw', host=host) |
| cmd_ip = cmd_ip or path_utils.get_install_path('ip', host=host) |
| cmd_netdump = (cmd_netdump or |
| path_utils.get_install_path('tcpdump', host=host)) |
| host_description = host_description or 'cap_%s' % uuid.uuid4().hex |
| if None in [cmd_ifconfig, cmd_iw, cmd_ip, cmd_netdump, host_description]: |
| if ignore_failures: |
| logging.warning('Creating a disabled packet capturer for %s.', |
| host_description) |
| return DisabledPacketCapturer() |
| else: |
| raise error.TestFail('Missing commands needed for ' |
| 'capturing packets') |
| |
| return PacketCapturer(host, host_description, cmd_ifconfig, cmd_ip, cmd_iw, |
| cmd_netdump) |
| |
| |
| class DisabledPacketCapturer(object): |
| """Delegate meant to look like it could take packet captures.""" |
| |
| @property |
| def capture_running(self): |
| """@return False""" |
| return False |
| |
| |
| def __init__(self): |
| pass |
| |
| |
| def __enter__(self): |
| return self |
| |
| |
| def __exit__(self): |
| pass |
| |
| |
| def close(self): |
| """No-op""" |
| |
| |
| def create_raw_monitor(self, phy, frequency, ht_type=None, |
| monitor_device=None): |
| """Appears to fail while creating a raw monitor device. |
| |
| @param phy string ignored. |
| @param frequency int ignored. |
| @param ht_type string ignored. |
| @param monitor_device string ignored. |
| @return None. |
| |
| """ |
| return None |
| |
| |
| def configure_raw_monitor(self, monitor_device, frequency, ht_type=None): |
| """Fails to configure a raw monitor. |
| |
| @param monitor_device string ignored. |
| @param frequency int ignored. |
| @param ht_type string ignored. |
| |
| """ |
| |
| |
| def create_managed_monitor(self, existing_dev, monitor_device=None): |
| """Fails to create a managed monitor device. |
| |
| @param existing_device string ignored. |
| @param monitor_device string ignored. |
| @return None |
| |
| """ |
| return None |
| |
| |
| def start_capture(self, interface, local_save_dir, |
| remote_file=None, snaplen=None): |
| """Fails to start a packet capture. |
| |
| @param interface string ignored. |
| @param local_save_dir string ignored. |
| @param remote_file string ignored. |
| @param snaplen int ignored. |
| |
| @raises PacketCapturesDisabledError. |
| |
| """ |
| raise PacketCapturesDisabledError() |
| |
| |
| def stop_capture(self, capture_pid=None): |
| """Stops all ongoing packet captures. |
| |
| @param capture_pid int ignored. |
| |
| """ |
| |
| |
| class PacketCapturer(object): |
| """Delegate with capability to initiate packet captures on a remote host.""" |
| |
| LIBPCAP_POLL_FREQ_SECS = 1 |
| |
| @property |
| def capture_running(self): |
| """@return True iff we have at least one ongoing packet capture.""" |
| if self._ongoing_captures: |
| return True |
| |
| return False |
| |
| |
| def __init__(self, host, host_description, cmd_ifconfig, cmd_ip, |
| cmd_iw, cmd_netdump, disable_captures=False): |
| self._cmd_netdump = cmd_netdump |
| self._cmd_iw = cmd_iw |
| self._cmd_ip = cmd_ip |
| self._cmd_ifconfig = cmd_ifconfig |
| self._host = host |
| self._ongoing_captures = {} |
| self._cap_num = 0 |
| self._if_num = 0 |
| self._created_managed_devices = [] |
| self._created_raw_devices = [] |
| self._host_description = host_description |
| |
| |
| def __enter__(self): |
| return self |
| |
| |
| def __exit__(self): |
| self.close() |
| |
| |
| def close(self): |
| """Stop ongoing captures and destroy all created devices.""" |
| self.stop_capture() |
| for device in self._created_managed_devices: |
| self._host.run("%s dev %s del" % (self._cmd_iw, device)) |
| self._created_managed_devices = [] |
| for device in self._created_raw_devices: |
| self._host.run("%s link set %s down" % (self._cmd_ip, device)) |
| self._host.run("%s dev %s del" % (self._cmd_iw, device)) |
| self._created_raw_devices = [] |
| |
| |
| def create_raw_monitor(self, phy, frequency, ht_type=None, |
| monitor_device=None): |
| """Create and configure a monitor type WiFi interface on a phy. |
| |
| If a device called |monitor_device| already exists, it is first removed. |
| |
| @param phy string phy name for created monitor (e.g. phy0). |
| @param frequency int frequency for created monitor to watch. |
| @param ht_type string optional HT type ('HT20', 'HT40+', or 'HT40-'). |
| @param monitor_device string name of monitor interface to create. |
| @return string monitor device name created or None on failure. |
| |
| """ |
| if not monitor_device: |
| monitor_device = 'mon%d' % self._if_num |
| self._if_num += 1 |
| |
| self._host.run('%s dev %s del' % (self._cmd_iw, monitor_device), |
| ignore_status=True) |
| result = self._host.run('%s phy %s interface add %s type monitor' % |
| (self._cmd_iw, |
| phy, |
| monitor_device), |
| ignore_status=True) |
| if result.exit_status: |
| logging.error('Failed creating raw monitor.') |
| return None |
| |
| self.configure_raw_monitor(monitor_device, frequency, ht_type) |
| self._created_raw_devices.append(monitor_device) |
| return monitor_device |
| |
| |
| def configure_raw_monitor(self, monitor_device, frequency, ht_type=None): |
| """Configure a raw monitor with frequency and HT params. |
| |
| Note that this will stomp on earlier device settings. |
| |
| @param monitor_device string name of device to configure. |
| @param frequency int WiFi frequency to dwell on. |
| @param ht_type string optional HT type ('HT20', 'HT40+', or 'HT40-'). |
| |
| """ |
| channel_args = str(frequency) |
| if ht_type: |
| ht_type = ht_type.upper() |
| channel_args = '%s %s' % (channel_args, ht_type) |
| if ht_type not in ('HT20', 'HT40+', 'HT40-'): |
| raise error.TestError('Cannot set HT mode: %s', ht_type) |
| |
| self._host.run("%s link set %s up" % (self._cmd_ip, monitor_device)) |
| self._host.run("%s dev %s set freq %s" % (self._cmd_iw, |
| monitor_device, |
| channel_args)) |
| |
| |
| def create_managed_monitor(self, existing_dev, monitor_device=None): |
| """Create a monitor type WiFi interface next to a managed interface. |
| |
| If a device called |monitor_device| already exists, it is first removed. |
| |
| @param existing_device string existing interface (e.g. mlan0). |
| @param monitor_device string name of monitor interface to create. |
| @return string monitor device name created or None on failure. |
| |
| """ |
| if not monitor_device: |
| monitor_device = 'mon%d' % self._if_num |
| self._if_num += 1 |
| self._host.run('%s dev %s del' % (self._cmd_iw, monitor_device), |
| ignore_status=True) |
| result = self._host.run('%s dev %s interface add %s type monitor' % |
| (self._cmd_iw, |
| existing_dev, |
| monitor_device), |
| ignore_status=True) |
| if result.exit_status: |
| logging.warning('Failed creating monitor.') |
| return None |
| |
| self._host.run('%s %s up' % (self._cmd_ifconfig, monitor_device)) |
| self._created_managed_devices.append(monitor_device) |
| return monitor_device |
| |
| |
| def _is_capture_active(self, remote_log_file): |
| """Check if a packet capture has completed initialization. |
| |
| @param remote_log_file string path to the capture's log file |
| @return True iff log file indicates that tcpdump is listening. |
| """ |
| return self._host.run( |
| 'grep "listening on" "%s"' % remote_log_file, ignore_status=True |
| ).exit_status == 0 |
| |
| |
| def start_capture(self, interface, local_save_dir, |
| remote_file=None, snaplen=None): |
| """Start a packet capture on an existing interface. |
| |
| @param interface string existing interface to capture on. |
| @param local_save_dir string directory on local machine to hold results. |
| @param remote_file string full path on remote host to hold the capture. |
| @param snaplen int maximum captured frame length. |
| @return int pid of started packet capture. |
| |
| """ |
| remote_file = (remote_file or |
| '/tmp/%s.%d.pcap' % (self._host_description, |
| self._cap_num)) |
| self._cap_num += 1 |
| remote_log_file = '%s.log' % remote_file |
| # Redirect output because SSH refuses to return until the child file |
| # descriptors are closed. |
| cmd = '%s -U -i %s -w %s -s %d >%s 2>&1 & echo $!' % ( |
| self._cmd_netdump, |
| interface, |
| remote_file, |
| snaplen or 0, |
| remote_log_file) |
| logging.debug('Starting managed packet capture') |
| pid = int(self._host.run(cmd).stdout) |
| self._ongoing_captures[pid] = (remote_file, |
| remote_log_file, |
| local_save_dir) |
| is_capture_active = lambda: self._is_capture_active(remote_log_file) |
| utils.poll_for_condition( |
| is_capture_active, |
| timeout=TCPDUMP_START_TIMEOUT_SECONDS, |
| sleep_interval=TCPDUMP_START_POLL_SECONDS, |
| desc='Timeout waiting for tcpdump to start.') |
| return pid |
| |
| |
| def stop_capture(self, capture_pid=None, local_save_dir=None, |
| local_pcap_filename=None): |
| """Stop an ongoing packet capture, or all ongoing packet captures. |
| |
| If |capture_pid| is given, stops that capture, otherwise stops all |
| ongoing captures. |
| |
| This method will sleep for a small amount of time, to ensure that |
| libpcap has completed its last poll(). The caller must ensure that |
| no unwanted traffic is received during this time. |
| |
| @param capture_pid int pid of ongoing packet capture or None. |
| @param local_save_dir path to directory to save pcap file in locally. |
| @param local_pcap_filename name of file to store pcap in |
| (basename only). |
| @return list of RemoteCaptureResult tuples |
| |
| """ |
| time.sleep(self.LIBPCAP_POLL_FREQ_SECS * 2) |
| |
| if capture_pid: |
| pids_to_kill = [capture_pid] |
| else: |
| pids_to_kill = list(self._ongoing_captures.keys()) |
| |
| results = [] |
| for pid in pids_to_kill: |
| self._host.run('kill -INT %d' % pid, ignore_status=True) |
| remote_pcap, remote_pcap_log, save_dir = self._ongoing_captures[pid] |
| pcap_filename = os.path.basename(remote_pcap) |
| pcap_log_filename = os.path.basename(remote_pcap_log) |
| if local_pcap_filename: |
| pcap_filename = os.path.join(local_save_dir or save_dir, |
| local_pcap_filename) |
| pcap_log_filename = os.path.join(local_save_dir or save_dir, |
| '%s.log' % local_pcap_filename) |
| pairs = [(remote_pcap, pcap_filename), |
| (remote_pcap_log, pcap_log_filename)] |
| |
| for remote_file, local_file in pairs: |
| self._host.get_file(remote_file, local_file) |
| self._host.run('rm -f %s' % remote_file) |
| |
| self._ongoing_captures.pop(pid) |
| results.append(CaptureResult(pcap_filename, |
| pcap_log_filename)) |
| return results |
