#! /usr/bin/python3
# networkd-dispatcher
# Dispatcher service for systemd-networkd
# Copyright(c) 2016 by wave++ "Yuri D'Elia" <wavexx@thregr.org>
# Distributed under GPLv3+ (see COPYING) WITHOUT ANY WARRANTY.
# Copyright(c) 2018-2022 by craftyguy "Clayton Craft" <clayton@craftyguy.net>
# Distributed under GPLv3+ (see COPYING) WITHOUT ANY WARRANTY.
from __future__ import print_function, division, generators, unicode_literals
import argparse
import collections
import errno
import json
import logging
import os
import pathlib
import re
import socket
import subprocess
import sys
# Try to import the dynamic glib, or try to fall back to static
try:
from gi.repository import GLib as glib # pragma: no cover
except ImportError: # pragma: no cover
import glib # pragma: no cover
import dbus
import dbus.mainloop.glib
logger = logging.getLogger('networkd-dispatcher')
# Detect up-front which commands we use exist
def resolve_path(cmdname):
for dirname in os.environ['PATH'].split(':'):
path = os.path.join(dirname, cmdname)
if os.path.exists(path):
return path
logger.warning('No valid path found for %s', cmdname)
return None
# Constants
NETWORKCTL = resolve_path('networkctl')
DEFAULT_SCRIPT_DIR = '/etc/networkd-dispatcher:/usr/lib/networkd-dispatcher'
# Supported wireless tools
IWCONFIG = resolve_path('iwconfig')
IW = resolve_path('iw')
LOG_FORMAT = '%(levelname)s:%(message)s'
SINGLETONS = {'Type', 'ESSID', 'OperationalState'}
# taken from https://www.freedesktop.org/software/systemd/man/networkctl.html
ADMIN_STATES = ['configured', 'configuring', 'failed', 'pending', 'unmanaged',
'linger', 'initialized']
OPER_STATES = ['carrier', 'degraded', 'degraded-carrier', 'dormant',
'enslaved', 'missing', 'no-carrier', 'off', 'routable']
AddressList = collections.namedtuple('AddressList', ['ipv4', 'ipv6'])
NetworkctlListState = collections.namedtuple('NetworkctlListState',
['idx', 'name', 'type',
'operational', 'administrative'])
class UnknownState(Exception):
pass
def unquote(buf, char='\\'):
"""Remove escape characters from iwconfig ESSID output"""
idx = 0
while True:
idx = buf.find(char, idx)
if idx < 0:
break
buf = buf[:idx] + buf[idx+1:]
idx += 1
return buf
def get_networkctl_list():
"""Update the mapping from interface index numbers to state"""
try:
out = subprocess.check_output([NETWORKCTL, 'list', '--no-pager',
'--no-legend'])
except subprocess.CalledProcessError as e:
logger.error('networkctl list failed: %s', e)
return []
result = []
for line in out.split(b'\n')[:-1]:
fields = line.decode('utf-8', errors='replace').split()
idx_s = fields.pop(0)
result.append(NetworkctlListState(int(idx_s), *fields))
return result
def get_networkctl_status(iface_name):
"""Return a dictionary mapping keys to lists (or strings if
in SINGLETONS)"""
data = collections.defaultdict(list)
try:
out = subprocess.check_output([NETWORKCTL, 'status', '--no-pager',
'--no-legend', '--lines=0', '--',
iface_name])
except subprocess.CalledProcessError as e:
logger.error('Failed to get interface "%s" status: %s', iface_name, e)
return data
out = out.decode('utf-8', errors='replace')
oldk = None
for line in out.split('\n')[1:-1]:
kv = line.split(': ', 1)
k = oldk if len(kv) == 1 else kv[0].strip()
v = kv[-1].strip()
if not v:
continue
# normalize some values that changed in v244 & v246
if k == 'Address':
v = re.sub(r' \(DHCP4.*\)$', '', v)
oldk = k
if k in SINGLETONS:
data[k] = v
else:
data[k].append(v)
return data
def get_wlan_essid(iface_name):
"""Given an interface name, return its ESSID"""
if IWCONFIG is None:
if IW is None:
logger.error('Unable to retrieve ESSID for wireless interface %s: '
'no supported wireless tool installed', iface_name)
return ''
return iw_get_ssid(iface_name)
return iwconfig_get_ssid(iface_name)
def iw_get_ssid(iface_name):
out = subprocess.check_output([IW, iface_name, 'link'])
lines = out.decode('utf-8', errors='replace').split('\n')
line = [s for s in lines if 'SSID' in s]
if not line:
logger.warning('Unable to retrieve ESSID for wireless interface %s.',
iface_name)
return ''
essid = line[0].rsplit(" ")[1]
return unquote(essid)
def iwconfig_get_ssid(iface_name):
out = subprocess.check_output([IWCONFIG, '--', iface_name])
line = out.split(b'\n', maxsplit=1)[0].decode('utf-8', errors='replace')
essid = line[line.find('ESSID:')+7:-3]
return unquote(essid)
def check_perms(path, mode=0o755, uid=0, gid=0):
""" Check that the given file or dir @ path has the given mode set, and is
owned by the given uid/gid. Symlinks are *not* followed. Raises
FileNotFoundError if path doesn't exist."""
if not os.path.exists(path):
raise FileNotFoundError
st = os.stat(path, follow_symlinks=False)
st_mode = st.st_mode & 0x00FFF
if st.st_uid == uid and st.st_gid == gid and st_mode == mode:
return True
logger.error("invalid permissions on %s. expected mode=%s, uid=%d, "
"gid=%d; got mode=%s, uid=%d, gid=%d", path, oct(mode), uid,
gid, oct(st_mode), st.st_uid, st.st_gid)
return False
def scripts_in_path(path, subdir):
"""Given directory names in PATH notation (separated by :), and a
subdirectory name, return a sorted list of executables
contained in that subdirectory, such that executables in earlier
path components override those with the same name in later path
components."""
script_list = []
base_filenames = set()
for one_path in path.split(":"):
one_path = os.path.join(one_path, subdir)
if not os.path.exists(one_path):
logger.debug("Path %r does not exist; skipping", one_path)
continue
base_filenames.update(os.listdir(one_path))
for filename in sorted(base_filenames):
for one_path in path.split(":"):
pathname = os.path.join(one_path, subdir, filename)
if os.path.isfile(pathname):
try:
realpath = pathlib.Path(pathname).resolve()
# Make sure that the file's parent dir has the correct
# perms, without following any symlinks
if not check_perms(os.path.dirname(pathname),
0o755, 0, 0):
continue
# Make sure file has correct perms, after following any
# symlink(s)
if not check_perms(realpath, 0o755, 0, 0):
continue
except FileNotFoundError:
continue
script_list.append(pathname)
break
return script_list
def parse_address_strings(addrs):
"""Given a list of addresses, discard uninteresting ones, and sort the rest
into IPv4 vs IPv6"""
ip4addrs = []
ip6addrs = []
for addr in addrs:
if addr.startswith('127.') or \
addr.startswith('fe80:'):
continue
if ':' in addr:
ip6addrs.append(addr)
elif '.' in addr:
ip4addrs.append(addr)
return AddressList(ip4addrs, ip6addrs)
def get_interface_data(iface):
"""Return JSON-serializable data representing all state needed to run
hooks for the given interface"""
data = {'Type': iface.type, 'OperationalState': iface.operational,
'AdministrativeState': iface.administrative,
"InterfaceName": iface.name}
# Always collect what data we can.
data.update(get_networkctl_status(iface.name))
# The returned state may be different than what was read from
# 'networkctl list', so construct state based on th iface data.
# See Issue #24.
data['State'] = (data.get('OperationalState', '') + " (" +
data.get('AdministrativeState', '') + ")")
if data.get('Type') == 'wlan':
data['ESSID'] = get_wlan_essid(iface.name)
return data
class Dispatcher():
iface_names_by_idx = {} # only changed on rescan
ifaces_by_name = {} # updated on every state change
def __init__(self, script_dir=DEFAULT_SCRIPT_DIR):
self.script_dir = script_dir
self._interface_scan()
def __repr__(self):
return f"<Dispatcher({self.__dict__})>"
def _interface_scan(self):
iface_list = get_networkctl_list()
# Append new interfaces, keeping old ones around to avoid hotplug race
# condition (issue #20)
for i in iface_list:
if i.idx not in self.iface_names_by_idx:
self.iface_names_by_idx[i.idx] = i.name
self.ifaces_by_name[i.name] = i
logger.debug('Performed interface scan; state: %r', self)
def register(self, bus=None):
"""Register this dispatcher to handle events from the given bus"""
if bus is None:
bus = dbus.SystemBus()
bus.add_signal_receiver(self._receive_signal,
bus_name='org.freedesktop.network1',
signal_name='PropertiesChanged',
path_keyword='path')
def trigger_all(self):
"""Immediately invoke all scripts for the last known (or initial)
states for each interface"""
logger.info('Triggering scripts for last-known state for all'
'interfaces')
for iface_name, iface in self.ifaces_by_name.items():
logger.debug('Running immediate triggers for %r', iface)
try:
self.handle_state(iface_name,
administrative_state=iface.administrative,
operational_state=iface.operational,
force=True)
except UnknownState as e:
logger.exception("Unknown state for interface %s: %s",
iface, str(e))
except Exception: # pylint: disable=broad-except
logger.exception("Error handling initial state for "
"interface %r", iface)
def get_scripts_list(self, state):
"""Return scripts for the given state"""
return scripts_in_path(self.script_dir, state + ".d")
def _handle_one_state(self, iface_name, state, state_type, force=False):
"""Process a single state change"""
try:
if state is None:
return
prior_iface = self.ifaces_by_name.get(iface_name)
if prior_iface is None:
logger.error('Attempting to handle state for unknown interface'
' %r', iface_name)
return
prior_state = getattr(prior_iface, state_type)
if force is False and state == prior_state:
logger.debug('No change represented by %s state %r for '
'interface %r', state_type, state, iface_name)
return
new_iface = prior_iface._replace(**{state_type: state})
self.ifaces_by_name[new_iface.name] = new_iface
self.run_hooks_for_state(new_iface, state)
# pylint: disable=broad-except
except Exception:
logger.exception('Error handling notification for interface %r '
'entering %s state %s', iface_name, state_type,
state)
def handle_state(self, iface_name, administrative_state=None,
operational_state=None, force=False):
if (administrative_state and
administrative_state.lower() not in ADMIN_STATES):
raise UnknownState(administrative_state)
if (operational_state and
operational_state.lower() not in OPER_STATES):
raise UnknownState(operational_state)
self._handle_one_state(iface_name, administrative_state,
'administrative', force=force)
self._handle_one_state(iface_name, operational_state, 'operational',
force=force)
def run_hooks_for_state(self, iface, state):
"""Run all hooks associated with a given state"""
# No actions to take? Do nothing.
script_list = self.get_scripts_list(state)
if not script_list:
logger.debug('Ignoring notification for interface %r entering '
'state %r: no triggers', iface, state)
return
# Collect data
data = get_interface_data(iface)
(v4addrs, v6addrs) = parse_address_strings(data.get('Address', ()))
# Set script env. variables
script_env = dict(os.environ)
script_env.update({
'ADDR': (data.get('Address', ['']) + [''])[0],
'ESSID': data.get('ESSID', ''),
'IP_ADDRS': ' '.join(v4addrs),
'IP6_ADDRS': ' '.join(v6addrs),
'IFACE': iface.name,
'STATE': str(state),
'AdministrativeState': data.get('AdministrativeState', ''),
'OperationalState': data.get('OperationalState', ''),
'json': json.dumps(data, sort_keys=True),
})
# run all valid scripts in the list
logger.debug('Running triggers for interface %r entering state %r '
'with environment %r', iface, state, script_env)
for script in script_list:
logger.info('Invoking %r for interface %s', script, iface.name)
ret = subprocess.Popen(script, env=script_env).wait()
if ret != 0:
logger.warning('Exit status %r from script %r invoked with '
'environment %r', ret, script, script_env)
def _receive_signal(self, typ, data, _, path):
logger.debug('Signal: typ=%r, data=%r, path=%r', typ, data, path)
if typ != 'org.freedesktop.network1.Link':
logger.debug('Ignoring signal received with unexpected typ %r',
typ)
return
if not path.startswith('/org/freedesktop/network1/link/_'):
logger.warning('Ignoring signal received with unexpected path %r',
path)
return
# Detect necessity of reloading map *before* filtering ignored states
# http://thread.gmane.org/gmane.comp.sysutils.systemd.devel/36460
idx = path[32:]
idx = int(chr(int(idx[:2], 16)) + idx[2:])
is_new_interface = False
if idx not in self.iface_names_by_idx:
# Try to reload configuration if even an ignored message is seen
logger.warning('Unknown index %r seen, reloading interface list',
idx)
self._interface_scan()
is_new_interface = True
try:
iface_name = self.iface_names_by_idx[idx]
except KeyError:
# Presumptive race condition: We reloaded, but the index is
# still invalid
logger.error('Unknown interface index %r seen even after reload',
idx)
return
operational_state = data.get('OperationalState', None)
administrative_state = data.get('AdministrativeState', None)
if ((operational_state is not None) or
(administrative_state is not None)):
try:
self.handle_state(iface_name,
administrative_state=str(administrative_state) # noqa
if administrative_state else None,
operational_state=str(operational_state)
if operational_state else None,
force=is_new_interface)
except UnknownState as e:
logger.exception("Unknown state for interface %s: %s",
iface_name, str(e))
# Handle interfaces that have been removed
if administrative_state == 'linger':
try:
self.iface_names_by_idx.pop(idx)
self.ifaces_by_name.pop(iface_name)
except KeyError:
logger.error('Unable to remove interface at index %r.', idx)
def sd_notify(**kwargs):
"""Systemd sd_notify implementation for Python.
Note: kwargs should contain the state to send to systemd"""
if not kwargs:
logger.error("sd_notify called with no state specified!")
return -errno.EINVAL
sock = None
try:
# Turn state, a dictionary, into a properly formatted string where
# each 'key=val' combo in the dictionary is separated by a \n
state_str = '\n'.join([f"{key}={val}" for (key, val)
in kwargs.items()])
env = os.environ.get('NOTIFY_SOCKET', None)
if not env:
# Process was not invoked with systemd
return -errno.EINVAL
if env[0] not in ('/', '@'):
logger.warning("NOTIFY_SOCKET is set, but does not contain a "
"legitimate value")
return -errno.EINVAL
if env[0] == '@':
env = '\0' + env[1:]
sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
if sock.sendto(bytearray(state_str, 'utf-8'), env) > 0:
return 1
# pylint: disable=broad-except
except Exception:
logger.exception("Ignoring unexpected error during sd_notify() "
"invocation")
if sock:
sock.close()
return 0
def parse_args(args):
"""Parses arguments from command line"""
ap = argparse.ArgumentParser(description='networkd dispatcher daemon')
ap.add_argument('-S', '--script-dir', action='store',
default=DEFAULT_SCRIPT_DIR,
help='Location under which to look for scripts [default: '
'%(default)s]')
ap.add_argument('-T', '--run-startup-triggers', action='store_true',
help='Generate events reflecting preexisting state and '
'behavior on startup [default: %(default)s]')
ap.add_argument('-v', '--verbose', action='count', default=0,
help='Increment verbosity level once per call')
ap.add_argument('-q', '--quiet', action='count', default=0,
help='Decrement verbosity level once per call')
return ap.parse_args(args)
def main():
args = parse_args(sys.argv[1:])
verbosity_num = (args.verbose - args.quiet)
if verbosity_num <= -2:
log_level = logging.CRITICAL
elif verbosity_num <= -1:
log_level = logging.ERROR
elif verbosity_num == 0:
log_level = logging.WARNING
elif verbosity_num == 1:
log_level = logging.INFO
else:
log_level = logging.DEBUG
logging.basicConfig(level=log_level, format=LOG_FORMAT)
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
if NETWORKCTL is None:
logger.critical('Unable to find networkctl command; cannot continue')
sd_notify(ERRNO=errno.ENOENT)
sys.exit(1)
dispatcher = Dispatcher(script_dir=args.script_dir)
dispatcher.register()
# After configuring the receiver, run initial operations
if args.run_startup_triggers:
dispatcher.trigger_all()
# main loop
mainloop = glib.MainLoop()
# Signal to systemd that service is runnning
sd_notify(READY=1)
logger.info('Startup complete')
mainloop.run()
def init():
if __name__ == '__main__':
main()
init()
# vim: ai et sts=4 sw=4 ts=4
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