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