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
# 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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# following functions: "AvahiService.add", "AvahiService.remove",
10
# "server_state_changed", "entry_group_state_changed", and some lines
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13
# Everything else is
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# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
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from dbus.mainloop.glib import DBusGMainLoop
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# Brief description of the operation of this program:
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# 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
70
# supply an OpenPGP certificate, and the fingerprint of this
71
# 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,
78
(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
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syslogger.setFormatter(logging.Formatter\
71
('Mandos: %(levelname)s: %(message)s'))
80
('%(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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85
class AvahiError(Exception):
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86
def __init__(self, value):
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class AvahiService(object):
93
"""An Avahi (Zeroconf) service.
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interface: integer; avahi.IF_UNSPEC or an interface index.
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101
Used to optionally bind to the specified interface.
97
name: string; Example: 'Mandos'
98
type: string; Example: '_mandos._tcp'.
99
See <http://www.dns-sd.org/ServiceTypes.html>
100
port: integer; what port to announce
101
TXT: list of strings; TXT record for the service
102
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
104
max_renames: integer; maximum number of renames
105
rename_count: integer; counter so we only rename after collisions
106
a sensible number of times
102
name = string; Example: "Mandos"
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type = string; Example: "_mandos._tcp".
104
See <http://www.dns-sd.org/ServiceTypes.html>
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port = integer; what port to announce
106
TXT = list of strings; TXT record for the service
107
domain = string; Domain to publish on, default to .local if empty.
108
host = string; Host to publish records for, default to localhost
110
max_renames = integer; maximum number of renames
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rename_count = integer; counter so we only rename after collisions
112
a sensible number of times
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def __init__(self, interface = avahi.IF_UNSPEC, name = None,
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115
type = None, port = None, TXT = None, domain = "",
110
host = "", max_renames = 32768):
116
host = "", max_renames = 12):
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"""An Avahi (Zeroconf) service. """
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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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133
u" retries, exiting.", rename_count)
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raise AvahiServiceError("Too many renames")
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self.name = server.GetAlternativeServiceName(self.name)
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logger.info(u"Changing name to %r ...", str(self.name))
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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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name = server.GetAlternativeServiceName(name)
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logger.notice(u"Changing name to %r ...", name)
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self.rename_count += 1
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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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host: string; available for use by the checker command
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fqdn: string (FQDN); 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
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def __init__(self, name = None, stop_hook=None, config={}):
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"""Note: the 'checker' key in 'config' sets the
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'checker_command' attribute and *not* the 'checker'
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def __init__(self, name=None, stop_hook=None, fingerprint=None,
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secret=None, secfile=None, fqdn=None, timeout=None,
226
interval=-1, checker=None):
227
"""Note: the 'checker' argument sets the 'checker_command'
228
attribute and not the 'checker' attribute.."""
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logger.debug(u"Creating client %r", self.name)
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# Uppercase and remove spaces from fingerprint for later
228
# comparison purposes with return value from the fingerprint()
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self.fingerprint = config["fingerprint"].upper()\
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# Uppercase and remove spaces from fingerprint
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# for later comparison purposes with return value of
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# the fingerprint() function
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self.fingerprint = fingerprint.upper().replace(u" ", u"")
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logger.debug(u" Fingerprint: %s", self.fingerprint)
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if "secret" in config:
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self.secret = config["secret"].decode(u"base64")
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elif "secfile" in config:
236
sf = open(config["secfile"])
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self.secret = secret.decode(u"base64")
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self.secret = sf.read()
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raise TypeError(u"No secret or secfile for client %s"
242
self.host = config.get("host", "")
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self.created = datetime.datetime.now()
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self.last_checked_ok = None
245
self.timeout = string_to_delta(config["timeout"])
246
self.interval = string_to_delta(config["interval"])
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
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self.stop_hook = stop_hook
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self.checker = None
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self.checker_initiator_tag = None
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self.stop_initiator_tag = None
251
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self.checker_callback_tag = None
252
self.check_command = config["checker"]
255
self.check_command = checker
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257
"""Start this client's checker and timeout hooks"""
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# 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,
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but not currently used."""
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# If this client doesn't have a secret, it is already stopped.
271
if hasattr(self, "secret") and self.secret:
272
logger.info(u"Stopping client %s", self.name)
275
logger.debug(u"Stopping client %s", self.name)
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self.secret = None
294
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self.checker = None
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if os.WIFEXITED(condition) \
296
299
and (os.WEXITSTATUS(condition) == 0):
297
logger.info(u"Checker for %(name)s succeeded",
300
logger.debug(u"Checker for %(name)s succeeded",
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302
self.last_checked_ok = now
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gobject.source_remove(self.stop_initiator_tag)
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self.stop_initiator_tag = gobject.timeout_add\
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308
logger.warning(u"Checker for %(name)s crashed?",
308
logger.info(u"Checker for %(name)s failed",
311
logger.debug(u"Checker for %(name)s failed",
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def start_checker(self):
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"""Start a new checker subprocess if one is not running.
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If a checker already exists, leave it running and do
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u' %s', self.check_command, error)
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return True # Try again later
338
logger.info(u"Starting checker %r for %s",
340
# We don't need to redirect stdout and stderr, since
341
# in normal mode, that is already done by daemon(),
342
# and in debug mode we don't want to. (Stdin is
343
# always replaced by /dev/null.)
341
logger.debug(u"Starting checker %r for %s",
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343
self.checker = subprocess.Popen(command,
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shell=True, cwd="/")
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self.checker_callback_tag = gobject.child_watch_add\
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347
(self.checker.pid,
349
348
self.checker_callback)
350
except OSError, error:
349
except subprocess.OSError, error:
351
350
logger.error(u"Failed to start subprocess: %s",
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352
# Re-run this periodically if run by gobject.timeout_add
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self.checker_callback_tag = None
360
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if getattr(self, "checker", None) is None:
362
logger.debug(u"Stopping checker for %(name)s", vars(self))
361
logger.debug("Stopping checker for %(name)s", vars(self))
364
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os.kill(self.checker.pid, signal.SIGTERM)
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397
def fingerprint(openpgp):
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"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\
400
403
# New GnuTLS "datum" with the OpenPGP public key
401
404
datum = gnutls.library.types.gnutls_datum_t\
402
405
(ctypes.cast(ctypes.c_char_p(openpgp),
403
406
ctypes.POINTER(ctypes.c_ubyte)),
404
407
ctypes.c_uint(len(openpgp)))
405
# New empty GnuTLS certificate
406
crt = gnutls.library.types.gnutls_openpgp_crt_t()
407
gnutls.library.functions.gnutls_openpgp_crt_init\
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408
# Import the OpenPGP public key into the certificate
410
gnutls.library.functions.gnutls_openpgp_crt_import\
411
(crt, ctypes.byref(datum),
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
413
# Verify the self signature in the key
414
crtverify = ctypes.c_uint();
415
gnutls.library.functions.gnutls_openpgp_crt_verify_self\
416
(crt, ctypes.c_uint(0), ctypes.byref(crtverify))
417
if crtverify.value != 0:
418
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
419
raise gnutls.errors.CertificateSecurityError("Verify failed")
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
420
413
# New buffer for the fingerprint
421
414
buffer = ctypes.create_string_buffer(20)
422
415
buffer_length = ctypes.c_size_t()
438
431
Note: This will run in its own forked process."""
440
433
def handle(self):
441
logger.info(u"TCP connection from: %s",
434
logger.debug(u"TCP connection from: %s",
442
435
unicode(self.client_address))
443
436
session = gnutls.connection.ClientSession\
444
437
(self.request, gnutls.connection.X509Credentials())
446
line = self.request.makefile().readline()
447
logger.debug(u"Protocol version: %r", line)
449
if int(line.strip().split()[0]) > 1:
451
except (ValueError, IndexError, RuntimeError), error:
452
logger.error(u"Unknown protocol version: %s", error)
455
438
# Note: gnutls.connection.X509Credentials is really a generic
456
439
# GnuTLS certificate credentials object so long as no X.509
457
440
# keys are added to it. Therefore, we can use it here despite
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454
session.handshake()
472
455
except gnutls.errors.GNUTLSError, error:
473
logger.warning(u"Handshake failed: %s", error)
456
logger.debug(u"Handshake failed: %s", error)
474
457
# Do not run session.bye() here: the session is not
475
458
# established. Just abandon the request.
478
461
fpr = fingerprint(peer_certificate(session))
479
462
except (TypeError, gnutls.errors.GNUTLSError), error:
480
logger.warning(u"Bad certificate: %s", error)
463
logger.debug(u"Bad certificate: %s", error)
483
466
logger.debug(u"Fingerprint: %s", fpr)
490
logger.warning(u"Client not found for fingerprint: %s",
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
494
476
# Have to check if client.still_valid(), since it is possible
495
477
# that the client timed out while establishing the GnuTLS
497
479
if not client.still_valid():
498
logger.warning(u"Client %(name)s is invalid",
480
logger.debug(u"Client %(name)s is invalid", vars(client))
528
509
"""This overrides the normal server_bind() function
529
510
to bind to an interface if one was specified, and also NOT to
530
511
bind to an address or port if they were not specified."""
531
if self.settings["interface"]:
512
if self.settings["interface"] != avahi.IF_UNSPEC:
532
513
# 25 is from /usr/include/asm-i486/socket.h
533
514
SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
537
518
self.settings["interface"])
538
519
except socket.error, error:
539
520
if error[0] == errno.EPERM:
540
logger.error(u"No permission to"
541
u" bind to interface %s",
542
self.settings["interface"])
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
545
526
# Only bind(2) the socket if we really need to.
548
529
in6addr_any = "::"
549
530
self.server_address = (in6addr_any,
550
531
self.server_address[1])
551
elif not self.server_address[1]:
532
elif self.server_address[1] is None:
552
533
self.server_address = (self.server_address[0],
554
# if self.settings["interface"]:
555
# self.server_address = (self.server_address[0],
561
535
return super(type(self), self).server_bind()
574
548
datetime.timedelta(1)
575
549
>>> string_to_delta(u'1w')
576
550
datetime.timedelta(7)
577
>>> string_to_delta('5m 30s')
578
datetime.timedelta(0, 330)
580
timevalue = datetime.timedelta(0)
581
for s in interval.split():
583
suffix=unicode(s[-1])
586
delta = datetime.timedelta(value)
588
delta = datetime.timedelta(0, value)
590
delta = datetime.timedelta(0, 0, 0, 0, value)
592
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
594
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
597
except (ValueError, IndexError):
553
suffix=unicode(interval[-1])
554
value=int(interval[:-1])
556
delta = datetime.timedelta(value)
558
delta = datetime.timedelta(0, value)
560
delta = datetime.timedelta(0, 0, 0, 0, value)
562
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
564
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
567
except (ValueError, IndexError):
603
572
def server_state_changed(state):
604
573
"""Derived from the Avahi example code"""
605
574
if state == avahi.SERVER_COLLISION:
606
logger.error(u"Server name collision")
575
logger.warning(u"Server name collision")
608
577
elif state == avahi.SERVER_RUNNING:
624
593
raise AvahiGroupError("State changed: %s", str(error))
626
def if_nametoindex(interface):
595
def if_nametoindex(interface, _func=[None]):
627
596
"""Call the C function if_nametoindex(), or equivalent"""
628
global if_nametoindex
597
if _func[0] is not None:
598
return _func[0](interface)
630
600
if "ctypes.util" not in sys.modules:
631
601
import ctypes.util
632
if_nametoindex = ctypes.cdll.LoadLibrary\
633
(ctypes.util.find_library("c")).if_nametoindex
604
libc = ctypes.cdll.LoadLibrary\
605
(ctypes.util.find_library("c"))
606
func[0] = libc.if_nametoindex
607
return _func[0](interface)
634
611
except (OSError, AttributeError):
635
612
if "struct" not in sys.modules:
637
614
if "fcntl" not in sys.modules:
639
def if_nametoindex(interface):
616
def the_hard_way(interface):
640
617
"Get an interface index the hard way, i.e. using fcntl()"
641
618
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
642
619
s = socket.socket()
646
623
interface_index = struct.unpack("I", ifreq[16:20])[0]
647
624
return interface_index
648
return if_nametoindex(interface)
651
def daemon(nochdir = False, noclose = False):
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
652
630
"""See daemon(3). Standard BSD Unix function.
653
631
This should really exist as os.daemon, but it doesn't (yet)."""
675
651
global main_loop_started
676
652
main_loop_started = False
678
parser = OptionParser(version = "%%prog %s" % version)
654
parser = OptionParser()
679
655
parser.add_option("-i", "--interface", type="string",
680
656
metavar="IF", help="Bind to interface IF")
681
657
parser.add_option("-a", "--address", type="string",
684
660
help="Port number to receive requests on")
685
661
parser.add_option("--check", action="store_true", default=False,
686
662
help="Run self-test")
687
parser.add_option("--debug", action="store_true",
663
parser.add_option("--debug", action="store_true", default=False,
688
664
help="Debug mode; run in foreground and log to"
690
666
parser.add_option("--priority", type="string", help="GnuTLS"
715
691
# Parse config file for server-global settings
716
692
server_config = ConfigParser.SafeConfigParser(server_defaults)
717
693
del server_defaults
718
server_config.read(os.path.join(options.configdir, "mandos.conf"))
694
server_config.read(os.path.join(options.configdir, "server.conf"))
695
server_section = "server"
719
696
# Convert the SafeConfigParser object to a dict
720
server_settings = server_config.defaults()
697
server_settings = dict(server_config.items(server_section))
721
698
# Use getboolean on the boolean config option
722
699
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
724
701
del server_config
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
726
705
# Override the settings from the config file with command line
727
706
# options, if set.
734
713
# Now we have our good server settings in "server_settings"
736
debug = server_settings["debug"]
739
syslogger.setLevel(logging.WARNING)
740
console.setLevel(logging.WARNING)
742
if server_settings["servicename"] != "Mandos":
743
syslogger.setFormatter(logging.Formatter\
744
('Mandos (%s): %%(levelname)s:'
746
% server_settings["servicename"]))
748
715
# Parse config file with clients
749
716
client_defaults = { "timeout": "1h",
750
717
"interval": "5m",
751
"checker": "fping -q -- %(host)s",
718
"checker": "fping -q -- %%(fqdn)s",
754
720
client_config = ConfigParser.SafeConfigParser(client_defaults)
755
721
client_config.read(os.path.join(server_settings["configdir"],
773
737
avahi.DBUS_INTERFACE_SERVER )
774
738
# End of Avahi example code
740
debug = server_settings["debug"]
743
console = logging.StreamHandler()
744
# console.setLevel(logging.DEBUG)
745
console.setFormatter(logging.Formatter\
746
('%(levelname)s: %(message)s'))
747
logger.addHandler(console)
777
751
def remove_from_clients(client):
778
752
clients.remove(client)
780
logger.critical(u"No clients left, exiting")
754
logger.debug(u"No clients left, exiting")
783
clients.update(Set(Client(name = section,
757
clients.update(Set(Client(name=section,
784
758
stop_hook = remove_from_clients,
786
= dict(client_config.items(section)))
759
**(dict(client_config\
787
761
for section in client_config.sections()))
789
logger.critical(u"No clients defined")
793
# Redirect stdin so all checkers get /dev/null
794
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
795
os.dup2(null, sys.stdin.fileno())
800
logger.removeHandler(console)
801
# Close all input and output, do double fork, etc.
804
pidfilename = "/var/run/mandos/mandos.pid"
807
pidfile = open(pidfilename, "w")
808
pidfile.write(str(pid) + "\n")
812
logger.error(u"Could not write %s file with PID %d",
813
pidfilename, os.getpid())
816
767
"Cleanup function; run on exit"
844
795
# Find out what port we got
845
796
service.port = tcp_server.socket.getsockname()[1]
846
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
847
u" scope_id %d" % tcp_server.socket.getsockname())
797
logger.debug(u"Now listening on port %d", service.port)
849
#service.interface = tcp_server.socket.getsockname()[3]
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
852
804
# From the Avahi example code