# Copyright 2014 The Chromium OS Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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import logging
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import time
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from autotest_lib.client.common_lib import error
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from autotest_lib.client.common_lib.cros import avahi_utils
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from autotest_lib.client.common_lib.cros import virtual_ethernet_pair
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from autotest_lib.client.common_lib.cros.network import netblock
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from autotest_lib.client.cros import network_chroot
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from autotest_lib.client.cros import service_stopper
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from autotest_lib.client.cros import tcpdump
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class ChrootedAvahi(object):
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"""Helper object to start up avahi in a network chroot.
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Creates a virtual ethernet pair to enable communication with avahi.
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Does the necessary work to make avahi appear on DBus and allow it
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to claim its canonical service name.
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"""
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SERVICES_TO_STOP = ['avahi']
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# This side has to be called something special to avoid shill touching it.
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MONITOR_IF_IP = netblock.from_addr('10.9.8.1/24')
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# We'll drop the Avahi side into our network namespace.
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AVAHI_IF_IP = netblock.from_addr('10.9.8.2/24')
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AVAHI_IF_NAME = 'pseudoethernet0'
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TCPDUMP_FILE_PATH = '/var/log/peerd_dump.pcap'
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AVAHI_CONFIG_FILE = 'etc/avahi/avahi-daemon.conf'
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AVAHI_CONFIGS = {
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AVAHI_CONFIG_FILE :
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'[server]\n'
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'host-name-from-machine-id=yes\n'
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'browse-domains=\n'
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'use-ipv4=yes\n'
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'use-ipv6=no\n'
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'ratelimit-interval-usec=1000000\n'
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'ratelimit-burst=1000\n'
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'[wide-area]\n'
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'enable-wide-area=no\n'
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'[publish]\n'
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'publish-hinfo=no\n'
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'publish-workstation=no\n'
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'publish-aaaa-on-ipv4=no\n'
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'publish-a-on-ipv6=no\n'
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'[rlimits]\n'
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'rlimit-core=0\n'
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'rlimit-data=4194304\n'
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'rlimit-fsize=1024\n'
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'rlimit-nofile=768\n'
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'rlimit-stack=4194304\n'
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'rlimit-nproc=10\n',
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'etc/passwd' :
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'root:x:0:0:root:/root:/bin/bash\n'
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'avahi:*:238:238::/dev/null:/bin/false\n',
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'etc/group' :
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'avahi:x:238:\n',
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}
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AVAHI_LOG_FILE = '/var/log/avahi.log'
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AVAHI_PID_FILE = 'run/avahi-daemon/pid'
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AVAHI_UP_TIMEOUT_SECONDS = 10
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def __init__(self, unchrooted_interface_name='pseudoethernet1'):
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"""Construct a chrooted instance of Avahi.
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@param unchrooted_interface_name: string name of interface to leave
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outside the network chroot. This interface will be connected
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to the end Avahi is listening on.
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"""
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self._unchrooted_interface_name = unchrooted_interface_name
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self._services = None
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self._vif = None
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self._tcpdump = None
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self._chroot = None
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@property
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def unchrooted_interface_name(self):
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"""Get the name of the end of the VirtualEthernetPair not in the chroot.
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The network chroot works by isolating avahi inside with one end of a
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virtual ethernet pair. The outside world needs to interact with the
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other end in order to talk to avahi.
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@return name of interface not inside the chroot.
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"""
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return self._unchrooted_interface_name
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@property
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def avahi_interface_addr(self):
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"""@return string ip address of interface belonging to avahi."""
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return self.AVAHI_IF_IP.addr
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@property
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def hostname(self):
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"""@return string hostname claimed by avahi on |self.dns_domain|."""
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return avahi_utils.avahi_get_hostname()
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@property
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def dns_domain(self):
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"""@return string DNS domain in use by avahi (e.g. 'local')."""
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return avahi_utils.avahi_get_domain_name()
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def start(self):
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"""Start up the chrooted Avahi instance."""
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# Prevent weird interactions between services which talk to Avahi.
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# TODO(wiley) Does Chrome need to die here as well?
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self._services = service_stopper.ServiceStopper(
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self.SERVICES_TO_STOP)
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self._services.stop_services()
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# We don't want Avahi talking to the real world, so give it a nice
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# fake interface to use. We'll watch the other half of the pair.
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self._vif = virtual_ethernet_pair.VirtualEthernetPair(
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interface_name=self.unchrooted_interface_name,
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peer_interface_name=self.AVAHI_IF_NAME,
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interface_ip=self.MONITOR_IF_IP.netblock,
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peer_interface_ip=self.AVAHI_IF_IP.netblock,
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# Moving one end into the chroot causes errors.
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ignore_shutdown_errors=True)
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self._vif.setup()
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if not self._vif.is_healthy:
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raise error.TestError('Failed to setup virtual ethernet pair.')
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# By default, take a packet capture of everything Avahi sends out.
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self._tcpdump = tcpdump.Tcpdump(self.unchrooted_interface_name,
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self.TCPDUMP_FILE_PATH)
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# We're going to run Avahi in a network namespace to avoid interactions
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# with the outside world.
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self._chroot = network_chroot.NetworkChroot(self.AVAHI_IF_NAME,
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self.AVAHI_IF_IP.addr,
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self.AVAHI_IF_IP.prefix_len)
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self._chroot.add_config_templates(self.AVAHI_CONFIGS)
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self._chroot.add_root_directories(['etc/avahi', 'etc/avahi/services'])
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self._chroot.add_copied_config_files(['etc/resolv.conf',
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'etc/avahi/hosts'])
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self._chroot.add_startup_command(
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'/usr/sbin/avahi-daemon --file=/%s >%s 2>&1' %
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(self.AVAHI_CONFIG_FILE, self.AVAHI_LOG_FILE))
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self._chroot.bridge_dbus_namespaces()
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self._chroot.startup()
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# Wait for Avahi to come up, claim its DBus name, settle on a hostname.
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start_time = time.time()
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while time.time() - start_time < self.AVAHI_UP_TIMEOUT_SECONDS:
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if avahi_utils.avahi_ping():
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break
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time.sleep(0.2)
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else:
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raise error.TestFail('Avahi did not come up in time.')
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def close(self):
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"""Clean up the chrooted Avahi instance."""
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if self._chroot:
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# TODO(wiley) This is sloppy. Add a helper to move the logs over.
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for line in self._chroot.get_log_contents().splitlines():
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logging.debug(line)
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self._chroot.kill_pid_file(self.AVAHI_PID_FILE)
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self._chroot.shutdown()
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if self._tcpdump:
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self._tcpdump.stop()
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if self._vif:
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self._vif.teardown()
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if self._services:
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self._services.restore_services()
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