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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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
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# server program acts as a TLS "client" while a connecting client acts
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# 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
72
# 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)
68
(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
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syslogger.setFormatter(logging.Formatter\
80
('%(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()
75
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
77
logger.addHandler(console)
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class AvahiError(Exception):
86
80
def __init__(self, value):
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class AvahiService(object):
93
"""An Avahi (Zeroconf) service.
100
95
interface: integer; avahi.IF_UNSPEC or an interface index.
101
96
Used to optionally bind to the specified interface.
102
name = string; Example: "Mandos"
103
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
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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
110
max_renames = integer; maximum number of renames
111
rename_count = integer; counter so we only rename after collisions
112
a sensible number of times
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name: string; Example: 'Mandos'
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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
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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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type = None, port = None, TXT = None, domain = "",
116
host = "", max_renames = 12):
117
"""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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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 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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136
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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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
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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):
227
"""Note: the 'checker' argument sets the 'checker_command'
228
attribute and not the 'checker' attribute.."""
221
def __init__(self, name = None, stop_hook=None, config={}):
222
"""Note: the 'checker' key in 'config' sets the
223
'checker_command' attribute and *not* the 'checker'
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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
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# the fingerprint() function
234
self.fingerprint = fingerprint.upper().replace(u" ", u"")
227
# Uppercase and remove spaces from fingerprint for later
228
# comparison purposes with return value from the fingerprint()
230
self.fingerprint = config["fingerprint"].upper()\
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logger.debug(u" Fingerprint: %s", self.fingerprint)
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self.secret = secret.decode(u"base64")
233
if "secret" in config:
234
self.secret = config["secret"].decode(u"base64")
235
elif "secfile" in config:
236
sf = open(config["secfile"])
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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", "")
246
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self.created = datetime.datetime.now()
247
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self.last_checked_ok = None
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
245
self.timeout = string_to_delta(config["timeout"])
246
self.interval = string_to_delta(config["interval"])
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self.stop_hook = stop_hook
251
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self.checker = None
252
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self.checker_initiator_tag = None
253
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self.stop_initiator_tag = None
254
251
self.checker_callback_tag = None
255
self.check_command = checker
252
self.check_command = config["checker"]
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"""Start this client's checker and timeout hooks"""
258
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# Schedule a new checker to be started an 'interval' from now,
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268
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.
275
logger.debug(u"Stopping client %s", self.name)
271
if hasattr(self, "secret") and self.secret:
272
logger.info(u"Stopping client %s", self.name)
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self.secret = None
297
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self.checker = None
298
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if os.WIFEXITED(condition) \
299
296
and (os.WEXITSTATUS(condition) == 0):
300
logger.debug(u"Checker for %(name)s succeeded",
297
logger.info(u"Checker for %(name)s succeeded",
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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\
308
305
logger.warning(u"Checker for %(name)s crashed?",
311
logger.debug(u"Checker for %(name)s failed",
308
logger.info(u"Checker for %(name)s failed",
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310
def start_checker(self):
314
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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
341
logger.debug(u"Starting checker %r for %s",
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.)
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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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(self.checker.pid,
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self.checker_callback)
349
except subprocess.OSError, error:
350
except OSError, error:
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351
logger.error(u"Failed to start subprocess: %s",
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# Re-run this periodically if run by gobject.timeout_add
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self.checker_callback_tag = None
359
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if getattr(self, "checker", None) is None:
361
logger.debug("Stopping checker for %(name)s", vars(self))
362
logger.debug(u"Stopping checker for %(name)s", vars(self))
363
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os.kill(self.checker.pid, signal.SIGTERM)
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398
def fingerprint(openpgp):
398
399
"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
400
# New GnuTLS "datum" with the OpenPGP public key
404
401
datum = gnutls.library.types.gnutls_datum_t\
405
402
(ctypes.cast(ctypes.c_char_p(openpgp),
406
403
ctypes.POINTER(ctypes.c_ubyte)),
407
404
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\
408
409
# 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)
410
gnutls.library.functions.gnutls_openpgp_crt_import\
411
(crt, ctypes.byref(datum),
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
413
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# New buffer for the fingerprint
414
414
buffer = ctypes.create_string_buffer(20)
415
415
buffer_length = ctypes.c_size_t()
431
431
Note: This will run in its own forked process."""
433
433
def handle(self):
434
logger.debug(u"TCP connection from: %s",
434
logger.info(u"TCP connection from: %s",
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435
unicode(self.client_address))
436
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session = gnutls.connection.ClientSession\
437
437
(self.request, gnutls.connection.X509Credentials())
439
line = self.request.makefile().readline()
440
logger.debug(u"Protocol version: %r", line)
442
if int(line.strip().split()[0]) > 1:
444
except (ValueError, IndexError, RuntimeError), error:
445
logger.error(u"Unknown protocol version: %s", error)
438
448
# Note: gnutls.connection.X509Credentials is really a generic
439
449
# GnuTLS certificate credentials object so long as no X.509
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450
# keys are added to it. Therefore, we can use it here despite
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session.handshake()
455
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except gnutls.errors.GNUTLSError, error:
456
logger.debug(u"Handshake failed: %s", error)
466
logger.warning(u"Handshake failed: %s", error)
457
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# Do not run session.bye() here: the session is not
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# established. Just abandon the request.
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fpr = fingerprint(peer_certificate(session))
462
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except (TypeError, gnutls.errors.GNUTLSError), error:
463
logger.debug(u"Bad certificate: %s", error)
473
logger.warning(u"Bad certificate: %s", error)
466
476
logger.debug(u"Fingerprint: %s", fpr)
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
483
logger.warning(u"Client not found for fingerprint: %s",
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487
# Have to check if client.still_valid(), since it is possible
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# that the client timed out while establishing the GnuTLS
479
490
if not client.still_valid():
480
logger.debug(u"Client %(name)s is invalid", vars(client))
491
logger.warning(u"Client %(name)s is invalid",
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521
"""This overrides the normal server_bind() function
510
522
to bind to an interface if one was specified, and also NOT to
511
523
bind to an address or port if they were not specified."""
512
if self.settings["interface"] != avahi.IF_UNSPEC:
524
if self.settings["interface"]:
513
525
# 25 is from /usr/include/asm-i486/socket.h
514
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SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
518
530
self.settings["interface"])
519
531
except socket.error, error:
520
532
if error[0] == errno.EPERM:
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
533
logger.error(u"No permission to"
534
u" bind to interface %s",
535
self.settings["interface"])
526
538
# Only bind(2) the socket if we really need to.
529
541
in6addr_any = "::"
530
542
self.server_address = (in6addr_any,
531
543
self.server_address[1])
532
elif self.server_address[1] is None:
544
elif not self.server_address[1]:
533
545
self.server_address = (self.server_address[0],
547
# if self.settings["interface"]:
548
# self.server_address = (self.server_address[0],
535
554
return super(type(self), self).server_bind()
548
567
datetime.timedelta(1)
549
568
>>> string_to_delta(u'1w')
550
569
datetime.timedelta(7)
570
>>> string_to_delta('5m 30s')
571
datetime.timedelta(0, 330)
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)
573
timevalue = datetime.timedelta(0)
574
for s in interval.split():
576
suffix=unicode(s[-1])
579
delta = datetime.timedelta(value)
581
delta = datetime.timedelta(0, value)
583
delta = datetime.timedelta(0, 0, 0, 0, value)
585
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
587
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
590
except (ValueError, IndexError):
567
except (ValueError, IndexError):
572
596
def server_state_changed(state):
573
597
"""Derived from the Avahi example code"""
574
598
if state == avahi.SERVER_COLLISION:
575
logger.warning(u"Server name collision")
599
logger.error(u"Server name collision")
577
601
elif state == avahi.SERVER_RUNNING:
593
617
raise AvahiGroupError("State changed: %s", str(error))
595
def if_nametoindex(interface, _func=[None]):
619
def if_nametoindex(interface):
596
620
"""Call the C function if_nametoindex(), or equivalent"""
597
if _func[0] is not None:
598
return _func[0](interface)
621
global if_nametoindex
600
623
if "ctypes.util" not in sys.modules:
601
624
import ctypes.util
604
libc = ctypes.cdll.LoadLibrary\
605
(ctypes.util.find_library("c"))
606
func[0] = libc.if_nametoindex
607
return _func[0](interface)
625
if_nametoindex = ctypes.cdll.LoadLibrary\
626
(ctypes.util.find_library("c")).if_nametoindex
611
627
except (OSError, AttributeError):
612
628
if "struct" not in sys.modules:
614
630
if "fcntl" not in sys.modules:
616
def the_hard_way(interface):
632
def if_nametoindex(interface):
617
633
"Get an interface index the hard way, i.e. using fcntl()"
618
634
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
619
635
s = socket.socket()
623
639
interface_index = struct.unpack("I", ifreq[16:20])[0]
624
640
return interface_index
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
641
return if_nametoindex(interface)
644
def daemon(nochdir = False, noclose = False):
630
645
"""See daemon(3). Standard BSD Unix function.
631
646
This should really exist as os.daemon, but it doesn't (yet)."""
651
668
global main_loop_started
652
669
main_loop_started = False
654
parser = OptionParser()
671
parser = OptionParser(version = "%%prog %s" % version)
655
672
parser.add_option("-i", "--interface", type="string",
656
673
metavar="IF", help="Bind to interface IF")
657
674
parser.add_option("-a", "--address", type="string",
660
677
help="Port number to receive requests on")
661
678
parser.add_option("--check", action="store_true", default=False,
662
679
help="Run self-test")
663
parser.add_option("--debug", action="store_true", default=False,
680
parser.add_option("--debug", action="store_true",
664
681
help="Debug mode; run in foreground and log to"
666
683
parser.add_option("--priority", type="string", help="GnuTLS"
691
708
# Parse config file for server-global settings
692
709
server_config = ConfigParser.SafeConfigParser(server_defaults)
693
710
del server_defaults
694
server_config.read(os.path.join(options.configdir, "server.conf"))
695
server_section = "server"
711
server_config.read(os.path.join(options.configdir, "mandos.conf"))
696
712
# Convert the SafeConfigParser object to a dict
697
server_settings = dict(server_config.items(server_section))
713
server_settings = server_config.defaults()
698
714
# Use getboolean on the boolean config option
699
715
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
701
717
del server_config
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
705
719
# Override the settings from the config file with command line
706
720
# options, if set.
713
727
# Now we have our good server settings in "server_settings"
729
debug = server_settings["debug"]
732
syslogger.setLevel(logging.WARNING)
733
console.setLevel(logging.WARNING)
735
if server_settings["servicename"] != "Mandos":
736
syslogger.setFormatter(logging.Formatter\
737
('Mandos (%s): %%(levelname)s:'
739
% server_settings["servicename"]))
715
741
# Parse config file with clients
716
742
client_defaults = { "timeout": "1h",
717
743
"interval": "5m",
718
"checker": "fping -q -- %%(fqdn)s",
744
"checker": "fping -q -- %(host)s",
720
747
client_config = ConfigParser.SafeConfigParser(client_defaults)
721
748
client_config.read(os.path.join(server_settings["configdir"],
737
766
avahi.DBUS_INTERFACE_SERVER )
738
767
# 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)
751
770
def remove_from_clients(client):
752
771
clients.remove(client)
754
logger.debug(u"No clients left, exiting")
773
logger.critical(u"No clients left, exiting")
757
clients.update(Set(Client(name=section,
776
clients.update(Set(Client(name = section,
758
777
stop_hook = remove_from_clients,
759
**(dict(client_config\
779
= dict(client_config.items(section)))
761
780
for section in client_config.sections()))
782
logger.critical(u"No clients defined")
786
# Redirect stdin so all checkers get /dev/null
787
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
788
os.dup2(null, sys.stdin.fileno())
793
logger.removeHandler(console)
794
# Close all input and output, do double fork, etc.
797
pidfilename = "/var/run/mandos/mandos.pid"
800
pidfile = open(pidfilename, "w")
801
pidfile.write(str(pid) + "\n")
805
logger.error(u"Could not write %s file with PID %d",
806
pidfilename, os.getpid())
767
809
"Cleanup function; run on exit"
795
837
# Find out what port we got
796
838
service.port = tcp_server.socket.getsockname()[1]
797
logger.debug(u"Now listening on port %d", service.port)
839
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
840
u" scope_id %d" % tcp_server.socket.getsockname())
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
842
#service.interface = tcp_server.socket.getsockname()[3]
804
845
# From the Avahi example code