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".
9
# following functions: "AvahiService.add", "AvahiService.remove",
10
# "server_state_changed", "entry_group_state_changed", and some lines
13
13
# Everything else is
14
14
# Copyright © 2007-2008 Teddy Hogeborn & Björn Påhlsson
24
24
# GNU General Public License for more details.
26
26
# You should have received a copy of the GNU General Public License
27
# along with this program. If not, see
28
# <http://www.gnu.org/licenses/>.
27
# along with this program. If not, see <http://www.gnu.org/licenses/>.
30
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# Contact the authors at <mandos@fukt.bsnet.se>.
63
61
from dbus.mainloop.glib import DBusGMainLoop
64
# 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
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
73
# authentication or authorization is done by this server.
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logger = logging.Logger('mandos')
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syslogger = logging.handlers.SysLogHandler\
70
(facility = logging.handlers.SysLogHandler.LOG_DAEMON,
78
(facility = logging.handlers.SysLogHandler.LOG_DAEMON)
72
79
syslogger.setFormatter(logging.Formatter\
73
('Mandos: %(levelname)s: %(message)s'))
80
('%(levelname)s: %(message)s'))
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logger.addHandler(syslogger)
76
console = logging.StreamHandler()
77
console.setFormatter(logging.Formatter('%(name)s: %(levelname)s:'
79
logger.addHandler(console)
81
85
class AvahiError(Exception):
82
86
def __init__(self, value):
94
98
class AvahiService(object):
95
"""An Avahi (Zeroconf) service.
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100
interface: integer; avahi.IF_UNSPEC or an interface index.
98
101
Used to optionally bind to the specified interface.
99
name: string; Example: 'Mandos'
100
type: string; Example: '_mandos._tcp'.
101
See <http://www.dns-sd.org/ServiceTypes.html>
102
port: integer; what port to announce
103
TXT: list of strings; TXT record for the service
104
domain: string; Domain to publish on, default to .local if empty.
105
host: string; Host to publish records for, default is localhost
106
max_renames: integer; maximum number of renames
107
rename_count: integer; counter so we only rename after collisions
108
a sensible number of times
102
name = string; Example: "Mandos"
103
type = string; Example: "_mandos._tcp".
104
See <http://www.dns-sd.org/ServiceTypes.html>
105
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
111
rename_count = integer; counter so we only rename after collisions
112
a sensible number of times
110
114
def __init__(self, interface = avahi.IF_UNSPEC, name = None,
111
115
type = None, port = None, TXT = None, domain = "",
112
host = "", max_renames = 32768):
116
host = "", max_renames = 12):
117
"""An Avahi (Zeroconf) service. """
113
118
self.interface = interface
121
126
self.domain = domain
123
128
self.rename_count = 0
124
self.max_renames = max_renames
125
129
def rename(self):
126
130
"""Derived from the Avahi example code"""
127
131
if self.rename_count >= self.max_renames:
128
logger.critical(u"No suitable Zeroconf service name found"
129
u" after %i retries, exiting.",
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logger.critical(u"No suitable service name found after %i"
133
u" retries, exiting.", rename_count)
131
134
raise AvahiServiceError("Too many renames")
132
self.name = server.GetAlternativeServiceName(self.name)
133
logger.info(u"Changing Zeroconf service name to %r ...",
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syslogger.setFormatter(logging.Formatter\
136
('Mandos (%s): %%(levelname)s:'
137
' %%(message)s' % self.name))
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name = server.GetAlternativeServiceName(name)
136
logger.notice(u"Changing name to %r ...", 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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153
entry_group_state_changed)
155
logger.debug(u"Adding Zeroconf service '%s' of type '%s' ...",
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logger.debug(u"Adding service '%s' of type '%s' ...",
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service.name, service.type)
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group.AddService(
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157
self.interface, # interface
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fingerprint: string (40 or 32 hexadecimal digits); used to
177
176
uniquely identify the client
178
177
secret: bytestring; sent verbatim (over TLS) to client
179
host: string; available for use by the checker command
178
fqdn: string (FQDN); available for use by the checker command
180
179
created: datetime.datetime(); object creation, not client host
181
180
last_checked_ok: datetime.datetime() or None if not yet checked OK
182
181
timeout: datetime.timedelta(); How long from last_checked_ok
222
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interval = property(lambda self: self._interval,
224
223
del _set_interval
225
def __init__(self, name = None, stop_hook=None, config={}):
226
"""Note: the 'checker' key in 'config' sets the
227
'checker_command' attribute and *not* the 'checker'
224
def __init__(self, name=None, stop_hook=None, fingerprint=None,
225
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.."""
230
230
logger.debug(u"Creating client %r", self.name)
231
# Uppercase and remove spaces from fingerprint for later
232
# comparison purposes with return value from the fingerprint()
234
self.fingerprint = config["fingerprint"].upper()\
231
# 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"")
236
235
logger.debug(u" Fingerprint: %s", self.fingerprint)
237
if "secret" in config:
238
self.secret = config["secret"].decode(u"base64")
239
elif "secfile" in config:
240
sf = open(config["secfile"])
237
self.secret = secret.decode(u"base64")
241
240
self.secret = sf.read()
244
243
raise TypeError(u"No secret or secfile for client %s"
246
self.host = config.get("host", "")
247
246
self.created = datetime.datetime.now()
248
247
self.last_checked_ok = None
249
self.timeout = string_to_delta(config["timeout"])
250
self.interval = string_to_delta(config["interval"])
248
self.timeout = string_to_delta(timeout)
249
self.interval = string_to_delta(interval)
251
250
self.stop_hook = stop_hook
252
251
self.checker = None
253
252
self.checker_initiator_tag = None
254
253
self.stop_initiator_tag = None
255
254
self.checker_callback_tag = None
256
self.check_command = config["checker"]
255
self.check_command = checker
258
257
"""Start this client's checker and timeout hooks"""
259
258
# Schedule a new checker to be started an 'interval' from now,
272
271
The possibility that a client might be restarted is left open,
273
272
but not currently used."""
274
273
# If this client doesn't have a secret, it is already stopped.
275
if hasattr(self, "secret") and self.secret:
276
logger.info(u"Stopping client %s", self.name)
275
logger.debug(u"Stopping client %s", self.name)
277
276
self.secret = None
298
297
self.checker = None
299
298
if os.WIFEXITED(condition) \
300
299
and (os.WEXITSTATUS(condition) == 0):
301
logger.info(u"Checker for %(name)s succeeded",
300
logger.debug(u"Checker for %(name)s succeeded",
303
302
self.last_checked_ok = now
304
303
gobject.source_remove(self.stop_initiator_tag)
305
304
self.stop_initiator_tag = gobject.timeout_add\
309
308
logger.warning(u"Checker for %(name)s crashed?",
312
logger.info(u"Checker for %(name)s failed",
311
logger.debug(u"Checker for %(name)s failed",
314
313
def start_checker(self):
315
314
"""Start a new checker subprocess if one is not running.
316
315
If a checker already exists, leave it running and do
339
338
u' %s', self.check_command, error)
340
339
return True # Try again later
342
logger.info(u"Starting checker %r for %s",
344
# We don't need to redirect stdout and stderr, since
345
# in normal mode, that is already done by daemon(),
346
# and in debug mode we don't want to. (Stdin is
347
# always replaced by /dev/null.)
341
logger.debug(u"Starting checker %r for %s",
348
343
self.checker = subprocess.Popen(command,
350
345
shell=True, cwd="/")
351
346
self.checker_callback_tag = gobject.child_watch_add\
352
347
(self.checker.pid,
353
348
self.checker_callback)
354
except OSError, error:
349
except subprocess.OSError, error:
355
350
logger.error(u"Failed to start subprocess: %s",
357
352
# Re-run this periodically if run by gobject.timeout_add
363
358
self.checker_callback_tag = None
364
359
if getattr(self, "checker", None) is None:
366
logger.debug(u"Stopping checker for %(name)s", vars(self))
361
logger.debug("Stopping checker for %(name)s", vars(self))
368
363
os.kill(self.checker.pid, signal.SIGTERM)
402
397
def fingerprint(openpgp):
403
398
"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\
404
403
# New GnuTLS "datum" with the OpenPGP public key
405
404
datum = gnutls.library.types.gnutls_datum_t\
406
405
(ctypes.cast(ctypes.c_char_p(openpgp),
407
406
ctypes.POINTER(ctypes.c_ubyte)),
408
407
ctypes.c_uint(len(openpgp)))
409
# New empty GnuTLS certificate
410
crt = gnutls.library.types.gnutls_openpgp_crt_t()
411
gnutls.library.functions.gnutls_openpgp_crt_init\
413
408
# Import the OpenPGP public key into the certificate
414
gnutls.library.functions.gnutls_openpgp_crt_import\
415
(crt, ctypes.byref(datum),
416
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
417
# Verify the self signature in the key
418
crtverify = ctypes.c_uint();
419
gnutls.library.functions.gnutls_openpgp_crt_verify_self\
420
(crt, 0, ctypes.byref(crtverify))
421
if crtverify.value != 0:
422
gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
423
raise gnutls.errors.CertificateSecurityError("Verify failed")
409
ret = gnutls.library.functions.gnutls_openpgp_crt_import\
412
gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
424
413
# New buffer for the fingerprint
425
414
buffer = ctypes.create_string_buffer(20)
426
415
buffer_length = ctypes.c_size_t()
442
431
Note: This will run in its own forked process."""
444
433
def handle(self):
445
logger.info(u"TCP connection from: %s",
434
logger.debug(u"TCP connection from: %s",
446
435
unicode(self.client_address))
447
436
session = gnutls.connection.ClientSession\
448
437
(self.request, gnutls.connection.X509Credentials())
450
line = self.request.makefile().readline()
451
logger.debug(u"Protocol version: %r", line)
453
if int(line.strip().split()[0]) > 1:
455
except (ValueError, IndexError, RuntimeError), error:
456
logger.error(u"Unknown protocol version: %s", error)
459
438
# Note: gnutls.connection.X509Credentials is really a generic
460
439
# GnuTLS certificate credentials object so long as no X.509
461
440
# keys are added to it. Therefore, we can use it here despite
475
454
session.handshake()
476
455
except gnutls.errors.GNUTLSError, error:
477
logger.warning(u"Handshake failed: %s", error)
456
logger.debug(u"Handshake failed: %s", error)
478
457
# Do not run session.bye() here: the session is not
479
458
# established. Just abandon the request.
482
461
fpr = fingerprint(peer_certificate(session))
483
462
except (TypeError, gnutls.errors.GNUTLSError), error:
484
logger.warning(u"Bad certificate: %s", error)
463
logger.debug(u"Bad certificate: %s", error)
487
466
logger.debug(u"Fingerprint: %s", fpr)
494
logger.warning(u"Client not found for fingerprint: %s",
473
logger.debug(u"Client not found for fingerprint: %s", fpr)
498
476
# Have to check if client.still_valid(), since it is possible
499
477
# that the client timed out while establishing the GnuTLS
501
479
if not client.still_valid():
502
logger.warning(u"Client %(name)s is invalid",
480
logger.debug(u"Client %(name)s is invalid", vars(client))
528
504
if "clients" in kwargs:
529
505
self.clients = kwargs["clients"]
530
506
del kwargs["clients"]
532
507
return super(type(self), self).__init__(*args, **kwargs)
533
508
def server_bind(self):
534
509
"""This overrides the normal server_bind() function
535
510
to bind to an interface if one was specified, and also NOT to
536
511
bind to an address or port if they were not specified."""
537
if self.settings["interface"]:
512
if self.settings["interface"] != avahi.IF_UNSPEC:
538
513
# 25 is from /usr/include/asm-i486/socket.h
539
514
SO_BINDTODEVICE = getattr(socket, "SO_BINDTODEVICE", 25)
543
518
self.settings["interface"])
544
519
except socket.error, error:
545
520
if error[0] == errno.EPERM:
546
logger.error(u"No permission to"
547
u" bind to interface %s",
548
self.settings["interface"])
521
logger.warning(u"No permission to"
522
u" bind to interface %s",
523
self.settings["interface"])
551
526
# Only bind(2) the socket if we really need to.
554
529
in6addr_any = "::"
555
530
self.server_address = (in6addr_any,
556
531
self.server_address[1])
557
elif not self.server_address[1]:
532
elif self.server_address[1] is None:
558
533
self.server_address = (self.server_address[0],
560
# if self.settings["interface"]:
561
# self.server_address = (self.server_address[0],
567
535
return super(type(self), self).server_bind()
568
def server_activate(self):
570
return super(type(self), self).server_activate()
575
538
def string_to_delta(interval):
585
548
datetime.timedelta(1)
586
549
>>> string_to_delta(u'1w')
587
550
datetime.timedelta(7)
588
>>> string_to_delta('5m 30s')
589
datetime.timedelta(0, 330)
591
timevalue = datetime.timedelta(0)
592
for s in interval.split():
594
suffix=unicode(s[-1])
597
delta = datetime.timedelta(value)
599
delta = datetime.timedelta(0, value)
601
delta = datetime.timedelta(0, 0, 0, 0, value)
603
delta = datetime.timedelta(0, 0, 0, 0, 0, value)
605
delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
608
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):
614
572
def server_state_changed(state):
615
573
"""Derived from the Avahi example code"""
616
574
if state == avahi.SERVER_COLLISION:
617
logger.error(u"Zeroconf server name collision")
575
logger.warning(u"Server name collision")
619
577
elif state == avahi.SERVER_RUNNING:
623
581
def entry_group_state_changed(state, error):
624
582
"""Derived from the Avahi example code"""
625
logger.debug(u"Avahi state change: %i", state)
583
logger.debug(u"state change: %i", state)
627
585
if state == avahi.ENTRY_GROUP_ESTABLISHED:
628
logger.debug(u"Zeroconf service established.")
586
logger.debug(u"Service established.")
629
587
elif state == avahi.ENTRY_GROUP_COLLISION:
630
logger.warning(u"Zeroconf service name collision.")
588
logger.warning(u"Service name collision.")
632
590
elif state == avahi.ENTRY_GROUP_FAILURE:
633
logger.critical(u"Avahi: Error in group state changed %s",
591
logger.critical(u"Error in group state changed %s",
635
593
raise AvahiGroupError("State changed: %s", str(error))
637
def if_nametoindex(interface):
595
def if_nametoindex(interface, _func=[None]):
638
596
"""Call the C function if_nametoindex(), or equivalent"""
639
global if_nametoindex
597
if _func[0] is not None:
598
return _func[0](interface)
641
600
if "ctypes.util" not in sys.modules:
642
601
import ctypes.util
643
if_nametoindex = ctypes.cdll.LoadLibrary\
644
(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)
645
611
except (OSError, AttributeError):
646
612
if "struct" not in sys.modules:
648
614
if "fcntl" not in sys.modules:
650
def if_nametoindex(interface):
616
def the_hard_way(interface):
651
617
"Get an interface index the hard way, i.e. using fcntl()"
652
618
SIOCGIFINDEX = 0x8933 # From /usr/include/linux/sockios.h
653
619
s = socket.socket()
657
623
interface_index = struct.unpack("I", ifreq[16:20])[0]
658
624
return interface_index
659
return if_nametoindex(interface)
662
def daemon(nochdir = False, noclose = False):
625
_func[0] = the_hard_way
626
return _func[0](interface)
629
def daemon(nochdir, noclose):
663
630
"""See daemon(3). Standard BSD Unix function.
664
631
This should really exist as os.daemon, but it doesn't (yet)."""
686
651
global main_loop_started
687
652
main_loop_started = False
689
parser = OptionParser(version = "%%prog %s" % version)
654
parser = OptionParser()
690
655
parser.add_option("-i", "--interface", type="string",
691
656
metavar="IF", help="Bind to interface IF")
692
657
parser.add_option("-a", "--address", type="string",
695
660
help="Port number to receive requests on")
696
661
parser.add_option("--check", action="store_true", default=False,
697
662
help="Run self-test")
698
parser.add_option("--debug", action="store_true",
663
parser.add_option("--debug", action="store_true", default=False,
699
664
help="Debug mode; run in foreground and log to"
701
666
parser.add_option("--priority", type="string", help="GnuTLS"
726
691
# Parse config file for server-global settings
727
692
server_config = ConfigParser.SafeConfigParser(server_defaults)
728
693
del server_defaults
729
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"
730
696
# Convert the SafeConfigParser object to a dict
731
server_settings = server_config.defaults()
697
server_settings = dict(server_config.items(server_section))
732
698
# Use getboolean on the boolean config option
733
699
server_settings["debug"] = server_config.getboolean\
700
(server_section, "debug")
735
701
del server_config
702
if not server_settings["interface"]:
703
server_settings["interface"] = avahi.IF_UNSPEC
737
705
# Override the settings from the config file with command line
738
706
# options, if set.
745
713
# Now we have our good server settings in "server_settings"
747
debug = server_settings["debug"]
750
syslogger.setLevel(logging.WARNING)
751
console.setLevel(logging.WARNING)
753
if server_settings["servicename"] != "Mandos":
754
syslogger.setFormatter(logging.Formatter\
755
('Mandos (%s): %%(levelname)s:'
757
% server_settings["servicename"]))
759
715
# Parse config file with clients
760
716
client_defaults = { "timeout": "1h",
761
717
"interval": "5m",
762
"checker": "fping -q -- %(host)s",
718
"checker": "fping -q -- %%(fqdn)s",
765
720
client_config = ConfigParser.SafeConfigParser(client_defaults)
766
721
client_config.read(os.path.join(server_settings["configdir"],
770
tcp_server = IPv6_TCPServer((server_settings["address"],
771
server_settings["port"]),
773
settings=server_settings,
775
pidfilename = "/var/run/mandos.pid"
777
pidfile = open(pidfilename, "w")
778
except IOError, error:
779
logger.error("Could not open file %r", pidfilename)
784
uid = pwd.getpwnam("mandos").pw_uid
787
uid = pwd.getpwnam("nobody").pw_uid
791
gid = pwd.getpwnam("mandos").pw_gid
794
gid = pwd.getpwnam("nogroup").pw_gid
800
except OSError, error:
801
if error[0] != errno.EPERM:
805
725
service = AvahiService(name = server_settings["servicename"],
806
726
type = "_mandos._tcp", );
807
if server_settings["interface"]:
808
service.interface = if_nametoindex\
809
(server_settings["interface"])
815
732
DBusGMainLoop(set_as_default=True )
816
733
main_loop = gobject.MainLoop()
817
734
bus = dbus.SystemBus()
818
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
819
avahi.DBUS_PATH_SERVER),
820
avahi.DBUS_INTERFACE_SERVER)
735
server = dbus.Interface(
736
bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
737
avahi.DBUS_INTERFACE_SERVER )
821
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)
823
751
def remove_from_clients(client):
824
752
clients.remove(client)
826
logger.critical(u"No clients left, exiting")
754
logger.debug(u"No clients left, exiting")
829
clients.update(Set(Client(name = section,
757
clients.update(Set(Client(name=section,
830
758
stop_hook = remove_from_clients,
832
= dict(client_config.items(section)))
759
**(dict(client_config\
833
761
for section in client_config.sections()))
835
logger.critical(u"No clients defined")
839
# Redirect stdin so all checkers get /dev/null
840
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
841
os.dup2(null, sys.stdin.fileno())
846
logger.removeHandler(console)
847
# Close all input and output, do double fork, etc.
852
pidfile.write(str(pid) + "\n")
856
logger.error(u"Could not write to file %r with PID %d",
859
# "pidfile" was never created
864
767
"Cleanup function; run on exit"
884
787
for client in clients:
888
tcp_server.server_activate()
790
tcp_server = IPv6_TCPServer((server_settings["address"],
791
server_settings["port"]),
793
settings=server_settings,
890
795
# Find out what port we got
891
796
service.port = tcp_server.socket.getsockname()[1]
892
logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
893
u" scope_id %d" % tcp_server.socket.getsockname())
797
logger.debug(u"Now listening on port %d", service.port)
895
#service.interface = tcp_server.socket.getsockname()[3]
799
if not server_settings["interface"]:
800
service.interface = if_nametoindex\
801
(server_settings["interface"])
898
804
# From the Avahi example code