6
6
# This program is partly derived from an example program for an Avahi
7
7
# service publisher, downloaded from
8
8
# <http://avahi.org/wiki/PythonPublishExample>. This includes the
9
# following functions: "AvahiService.add", "AvahiService.remove",
10
# "server_state_changed", "entry_group_state_changed", and some lines
9
# methods "add" and "remove" in the "AvahiService" class, the
10
# "server_state_changed" and "entry_group_state_changed" functions,
11
# and some lines in "main".
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# Everything else is
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# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
27
# along with this program. If not, see <http://www.gnu.org/licenses/>.
27
# along with this program. If not, see
28
# <http://www.gnu.org/licenses/>.
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# Contact the authors at <mandos@fukt.bsnet.se>.
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from dbus.mainloop.glib import DBusGMainLoop
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# Brief description of the operation of this program:
66
# This server announces itself as a Zeroconf service. Connecting
67
# clients use the TLS protocol, with the unusual quirk that this
68
# server program acts as a TLS "client" while a connecting client acts
69
# as a TLS "server". The client (acting as a TLS "server") must
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# supply an OpenPGP certificate, and the fingerprint of this
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# certificate is used by this server to look up (in a list read from a
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# file at start time) which binary blob to give the client. No other
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# authentication or authorization is done by this server.
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logger = logging.Logger('mandos')
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syslogger = logging.handlers.SysLogHandler\
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(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
69
(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
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syslogger.setFormatter(logging.Formatter\
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('%(levelname)s: %(message)s'))
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('Mandos: %(levelname)s: %(message)s'))
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logger.addHandler(syslogger)
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console = logging.StreamHandler()
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console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
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logger.addHandler(console)
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class AvahiError(Exception):
86
81
def __init__(self, value):
98
93
class AvahiService(object):
94
"""An Avahi (Zeroconf) service.
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interface: integer; avahi.IF_UNSPEC or an interface index.
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Used to optionally bind to the specified interface.
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name = string; Example: "Mandos"
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type = string; Example: "_mandos._tcp".
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See <http://www.dns-sd.org/ServiceTypes.html>
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port = integer; what port to announce
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TXT = list of strings; TXT record for the service
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domain = string; Domain to publish on, default to .local if empty.
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host = string; Host to publish records for, default to localhost
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max_renames = integer; maximum number of renames
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rename_count = integer; counter so we only rename after collisions
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a sensible number of times
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name: string; Example: 'Mandos'
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type: string; Example: '_mandos._tcp'.
100
See <http://www.dns-sd.org/ServiceTypes.html>
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port: integer; what port to announce
102
TXT: list of strings; TXT record for the service
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domain: string; Domain to publish on, default to .local if empty.
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host: string; Host to publish records for, default is localhost
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max_renames: integer; maximum number of renames
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rename_count: integer; counter so we only rename after collisions
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a sensible number of times
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def __init__(self, interface = avahi.IF_UNSPEC, name = None,
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110
type = None, port = None, TXT = None, domain = "",
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host = "", max_renames = 12):
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"""An Avahi (Zeroconf) service. """
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host = "", max_renames = 32768):
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self.interface = interface
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self.domain = domain
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self.rename_count = 0
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self.max_renames = max_renames
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def rename(self):
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"""Derived from the Avahi example code"""
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if self.rename_count >= self.max_renames:
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logger.critical(u"No suitable service name found after %i"
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u" retries, exiting.", rename_count)
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logger.critical(u"No suitable Zeroconf service name found"
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u" after %i retries, exiting.",
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raise AvahiServiceError("Too many renames")
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name = server.GetAlternativeServiceName(name)
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logger.notice(u"Changing name to %r ...", name)
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self.name = server.GetAlternativeServiceName(self.name)
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logger.info(u"Changing Zeroconf service name to %r ...",
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syslogger.setFormatter(logging.Formatter\
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('Mandos (%s): %%(levelname)s:'
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' %%(message)s' % self.name))
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self.rename_count += 1
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avahi.DBUS_INTERFACE_ENTRY_GROUP)
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group.connect_to_signal('StateChanged',
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entry_group_state_changed)
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logger.debug(u"Adding service '%s' of type '%s' ...",
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logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
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service.name, service.type)
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group.AddService(
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self.interface, # interface
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fingerprint: string (40 or 32 hexadecimal digits); used to
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uniquely identify the client
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secret: bytestring; sent verbatim (over TLS) to client
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fqdn: string (FQDN); available for use by the checker command
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host: string; available for use by the checker command
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created: datetime.datetime(); object creation, not client host
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last_checked_ok: datetime.datetime() or None if not yet checked OK
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timeout: datetime.timedelta(); How long from last_checked_ok
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interval = property(lambda self: self._interval,
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del _set_interval
224
def __init__(self, name=None, stop_hook=None, fingerprint=None,
225
secret=None, secfile=None, fqdn=None, timeout=None,
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interval=-1, checker=None):
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"""Note: the 'checker' argument sets the 'checker_command'
228
attribute and not the 'checker' attribute.."""
224
def __init__(self, name = None, stop_hook=None, config={}):
225
"""Note: the 'checker' key in 'config' sets the
226
'checker_command' attribute and *not* the 'checker'
230
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logger.debug(u"Creating client %r", self.name)
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# Uppercase and remove spaces from fingerprint
232
# for later comparison purposes with return value of
233
# the fingerprint() function
234
self.fingerprint = fingerprint.upper().replace(u" ", u"")
230
# Uppercase and remove spaces from fingerprint for later
231
# comparison purposes with return value from the fingerprint()
233
self.fingerprint = config["fingerprint"].upper()\
235
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logger.debug(u" Fingerprint: %s", self.fingerprint)
237
self.secret = secret.decode(u"base64")
236
if "secret" in config:
237
self.secret = config["secret"].decode(u"base64")
238
elif "secfile" in config:
239
sf = open(config["secfile"])
240
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self.secret = sf.read()
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raise TypeError(u"No secret or secfile for client %s"
245
self.host = config.get("host", "")
246
246
self.created = datetime.datetime.now()
247
247
self.last_checked_ok = None
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
248
self.timeout = string_to_delta(config["timeout"])
249
self.interval = string_to_delta(config["interval"])
250
250
self.stop_hook = stop_hook
251
251
self.checker = None
252
252
self.checker_initiator_tag = None
253
253
self.stop_initiator_tag = None
254
254
self.checker_callback_tag = None
255
self.check_command = checker
255
self.check_command = config["checker"]
257
257
"""Start this client's checker and timeout hooks"""
258
258
# Schedule a new checker to be started an 'interval' from now,
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271
The possibility that a client might be restarted is left open,
272
272
but not currently used."""
273
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# If this client doesn't have a secret, it is already stopped.
275
logger.debug(u"Stopping client %s", self.name)
274
if hasattr(self, "secret") and self.secret:
275
logger.info(u"Stopping client %s", self.name)
276
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self.secret = None
297
297
self.checker = None
298
298
if os.WIFEXITED(condition) \
299
299
and (os.WEXITSTATUS(condition) == 0):
300
logger.debug(u"Checker for %(name)s succeeded",
300
logger.info(u"Checker for %(name)s succeeded",
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self.last_checked_ok = now
303
303
gobject.source_remove(self.stop_initiator_tag)
304
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self.stop_initiator_tag = gobject.timeout_add\
308
308
logger.warning(u"Checker for %(name)s crashed?",
311
logger.debug(u"Checker for %(name)s failed",
311
logger.info(u"Checker for %(name)s failed",
313
313
def start_checker(self):
314
314
"""Start a new checker subprocess if one is not running.
315
315
If a checker already exists, leave it running and do
338
338
u' %s', self.check_command, error)
339
339
return True # Try again later
341
logger.debug(u"Starting checker %r for %s",
341
logger.info(u"Starting checker %r for %s",
343
# We don't need to redirect stdout and stderr, since
344
# in normal mode, that is already done by daemon(),
345
# and in debug mode we don't want to. (Stdin is
346
# always replaced by /dev/null.)
343
347
self.checker = subprocess.Popen(command,
345
349
shell=True, cwd="/")
346
350
self.checker_callback_tag = gobject.child_watch_add\
347
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(self.checker.pid,
348
352
self.checker_callback)
349
except subprocess.OSError, error:
353
except OSError, error:
350
354
logger.error(u"Failed to start subprocess: %s",
352
356
# Re-run this periodically if run by gobject.timeout_add
358
362
self.checker_callback_tag = None
359
363
if getattr(self, "checker", None) is None:
361
logger.debug("Stopping checker for %(name)s", vars(self))
365
logger.debug(u"Stopping checker for %(name)s", vars(self))
363
367
os.kill(self.checker.pid, signal.SIGTERM)
397
401
def fingerprint(openpgp):
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402
"Convert an OpenPGP bytestring to a hexdigit fingerprint string"
399
# New empty GnuTLS certificate
400
crt = gnutls.library.types.gnutls_openpgp_crt_t()
401
gnutls.library.functions.gnutls_openpgp_crt_init\
403
403
# New GnuTLS "datum" with the OpenPGP public key
404
404
datum = gnutls.library.types.gnutls_datum_t\
405
405
(ctypes.cast(ctypes.c_char_p(openpgp),
406
406
ctypes.POINTER(ctypes.c_ubyte)),
407
407
ctypes.c_uint(len(openpgp)))
408
# New empty GnuTLS certificate
409
crt = gnutls.library.types.gnutls_openpgp_crt_t()
410
gnutls.library.functions.gnutls_openpgp_crt_init\
408
412
# Import the OpenPGP public key into the certificate
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
413
gnutls.library.functions.gnutls_openpgp_crt_import\
414
(crt, ctypes.byref(datum),
415
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
416
# Verify the self signature in the key
417
crtverify = ctypes.c_uint();
418
gnutls.library.functions.gnutls_openpgp_crt_verify_self\
419
(crt, 0, ctypes.byref(crtverify))
420
if crtverify.value != 0:
421
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
422
raise gnutls.errors.CertificateSecurityError("Verify failed")
413
423
# New buffer for the fingerprint
414
424
buffer = ctypes.create_string_buffer(20)
415
425
buffer_length = ctypes.c_size_t()
431
441
Note: This will run in its own forked process."""
433
443
def handle(self):
434
logger.debug(u"TCP connection from: %s",
444
logger.info(u"TCP connection from: %s",
435
445
unicode(self.client_address))
436
446
session = gnutls.connection.ClientSession\
437
447
(self.request, gnutls.connection.X509Credentials())
464
474
session.handshake()
465
475
except gnutls.errors.GNUTLSError, error:
466
logger.debug(u"Handshake failed: %s", error)
476
logger.warning(u"Handshake failed: %s", error)
467
477
# Do not run session.bye() here: the session is not
468
478
# established. Just abandon the request.
471
481
fpr = fingerprint(peer_certificate(session))
472
482
except (TypeError, gnutls.errors.GNUTLSError), error:
473
logger.debug(u"Bad certificate: %s", error)
483
logger.warning(u"Bad certificate: %s", error)
476
486
logger.debug(u"Fingerprint: %s", fpr)
483
logger.debug(u"Client not found for fingerprint: %s", fpr)
493
logger.warning(u"Client not found for fingerprint: %s",
486
497
# Have to check if client.still_valid(), since it is possible
487
498
# that the client timed out while establishing the GnuTLS
489
500
if not client.still_valid():
490
logger.debug(u"Client %(name)s is invalid", vars(client))
501
logger.warning(u"Client %(name)s is invalid",
528
540
self.settings["interface"])
529
541
except socket.error, error:
530
542
if error[0] == errno.EPERM:
531
logger.warning(u"No permission to"
532
u" bind to interface %s",
533
self.settings["interface"])
543
logger.error(u"No permission to"
544
u" bind to interface %s",
545
self.settings["interface"])
536
548
# Only bind(2) the socket if we really need to.
539
551
in6addr_any = "::"
540
552
self.server_address = (in6addr_any,
541
553
self.server_address[1])
542
elif self.server_address[1] is None:
554
elif not self.server_address[1]:
543
555
self.server_address = (self.server_address[0],
557
# if self.settings["interface"]:
558
# self.server_address = (self.server_address[0],
545
564
return super(type(self), self).server_bind()
558
577
datetime.timedelta(1)
559
578
>>> string_to_delta(u'1w')
560
579
datetime.timedelta(7)
580
>>> string_to_delta('5m 30s')
581
datetime.timedelta(0, 330)
563
suffix=unicode(interval[-1])
564
value=int(interval[:-1])
566
delta = datetime.timedelta(value)
568
delta = datetime.timedelta(0, value)
570
delta = datetime.timedelta(0, 0, 0, 0, value)
572
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
574
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
583
timevalue = datetime.timedelta(0)
584
for s in interval.split():
586
suffix=unicode(s[-1])
589
delta = datetime.timedelta(value)
591
delta = datetime.timedelta(0, value)
593
delta = datetime.timedelta(0, 0, 0, 0, value)
595
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
597
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
600
except (ValueError, IndexError):
577
except (ValueError, IndexError):
582
606
def server_state_changed(state):
583
607
"""Derived from the Avahi example code"""
584
608
if state == avahi.SERVER_COLLISION:
585
logger.warning(u"Server name collision")
609
logger.error(u"Zeroconf server name collision")
587
611
elif state == avahi.SERVER_RUNNING:
591
615
def entry_group_state_changed(state, error):
592
616
"""Derived from the Avahi example code"""
593
logger.debug(u"state change: %i", state)
617
logger.debug(u"Avahi state change: %i", state)
595
619
if state == avahi.ENTRY_GROUP_ESTABLISHED:
596
logger.debug(u"Service established.")
620
logger.debug(u"Zeroconf service established.")
597
621
elif state == avahi.ENTRY_GROUP_COLLISION:
598
logger.warning(u"Service name collision.")
622
logger.warning(u"Zeroconf service name collision.")
600
624
elif state == avahi.ENTRY_GROUP_FAILURE:
601
logger.critical(u"Error in group state changed %s",
625
logger.critical(u"Avahi: Error in group state changed %s",
603
627
raise AvahiGroupError("State changed: %s", str(error))
627
651
return if_nametoindex(interface)
630
def daemon(nochdir, noclose):
654
def daemon(nochdir = False, noclose = False):
631
655
"""See daemon(3). Standard BSD Unix function.
632
656
This should really exist as os.daemon, but it doesn't (yet)."""
652
678
global main_loop_started
653
679
main_loop_started = False
655
parser = OptionParser()
681
parser = OptionParser(version = "%%prog %s" % version)
656
682
parser.add_option("-i", "--interface", type="string",
657
683
metavar="IF", help="Bind to interface IF")
658
684
parser.add_option("-a", "--address", type="string",
661
687
help="Port number to receive requests on")
662
688
parser.add_option("--check", action="store_true", default=False,
663
689
help="Run self-test")
664
parser.add_option("--debug", action="store_true", default=False,
690
parser.add_option("--debug", action="store_true",
665
691
help="Debug mode; run in foreground and log to"
667
693
parser.add_option("--priority", type="string", help="GnuTLS"
692
718
# Parse config file for server-global settings
693
719
server_config = ConfigParser.SafeConfigParser(server_defaults)
694
720
del server_defaults
695
server_config.read(os.path.join(options.configdir, "server.conf"))
696
server_section = "server"
721
server_config.read(os.path.join(options.configdir, "mandos.conf"))
697
722
# Convert the SafeConfigParser object to a dict
698
server_settings = dict(server_config.items(server_section))
723
server_settings = server_config.defaults()
699
724
# Use getboolean on the boolean config option
700
725
server_settings["debug"] = server_config.getboolean\
701
(server_section, "debug")
702
727
del server_config
704
729
# Override the settings from the config file with command line
712
737
# Now we have our good server settings in "server_settings"
739
debug = server_settings["debug"]
742
syslogger.setLevel(logging.WARNING)
743
console.setLevel(logging.WARNING)
745
if server_settings["servicename"] != "Mandos":
746
syslogger.setFormatter(logging.Formatter\
747
('Mandos (%s): %%(levelname)s:'
749
% server_settings["servicename"]))
714
751
# Parse config file with clients
715
752
client_defaults = { "timeout": "1h",
716
753
"interval": "5m",
717
"checker": "fping -q -- %%(fqdn)s",
754
"checker": "fping -q -- %(host)s",
719
757
client_config = ConfigParser.SafeConfigParser(client_defaults)
720
758
client_config.read(os.path.join(server_settings["configdir"],
724
762
service = AvahiService(name = server_settings["servicename"],
725
763
type = "_mandos._tcp", );
726
764
if server_settings["interface"]:
727
service.interface = if_nametoindex(server_settings["interface"])
765
service.interface = if_nametoindex\
766
(server_settings["interface"])
733
772
DBusGMainLoop(set_as_default=True )
734
773
main_loop = gobject.MainLoop()
735
774
bus = dbus.SystemBus()
736
server = dbus.Interface(
737
bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
738
avahi.DBUS_INTERFACE_SERVER )
775
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
776
avahi.DBUS_PATH_SERVER),
777
avahi.DBUS_INTERFACE_SERVER)
739
778
# End of Avahi example code
741
debug = server_settings["debug"]
744
console = logging.StreamHandler()
745
# console.setLevel(logging.DEBUG)
746
console.setFormatter(logging.Formatter\
747
('%(levelname)s: %(message)s'))
748
logger.addHandler(console)
752
781
def remove_from_clients(client):
753
782
clients.remove(client)
755
logger.debug(u"No clients left, exiting")
784
logger.critical(u"No clients left, exiting")
758
clients.update(Set(Client(name=section,
787
clients.update(Set(Client(name = section,
759
788
stop_hook = remove_from_clients,
760
**(dict(client_config\
790
= dict(client_config.items(section)))
762
791
for section in client_config.sections()))
793
logger.critical(u"No clients defined")
797
# Redirect stdin so all checkers get /dev/null
798
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
799
os.dup2(null, sys.stdin.fileno())
804
logger.removeHandler(console)
805
# Close all input and output, do double fork, etc.
808
pidfilename = "/var/run/mandos/mandos.pid"
811
pidfile = open(pidfilename, "w")
812
pidfile.write(str(pid) + "\n")
816
logger.error(u"Could not write %s file with PID %d",
817
pidfilename, os.getpid())
768
820
"Cleanup function; run on exit"
796
848
# Find out what port we got
797
849
service.port = tcp_server.socket.getsockname()[1]
798
logger.debug(u"Now listening on address %r, port %d, flowinfo %d,"
799
u" scope_id %d" % tcp_server.socket.getsockname())
850
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
851
u" scope_id %d" % tcp_server.socket.getsockname())
801
853
#service.interface = tcp_server.socket.getsockname()[3]