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# This program is partly derived from an example program for an Avahi
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# service publisher, downloaded from
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# <http://avahi.org/wiki/PythonPublishExample>. This includes the
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# following functions: "AvahiService.add", "AvahiService.remove",
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# "server_state_changed", "entry_group_state_changed", and some lines
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# methods "add" and "remove" in the "AvahiService" class, the
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# "server_state_changed" and "entry_group_state_changed" functions,
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# 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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# Copyright © 2008 Teddy Hogeborn & Björn Påhlsson
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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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
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# along with this program. If not, see
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# <http://www.gnu.org/licenses/>.
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# Contact the authors at <mandos@fukt.bsnet.se>.
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import logging.handlers
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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
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# 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
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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)
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(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):
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def __init__(self, value):
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super(AvahiError, self).__init__()
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return repr(self.value)
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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 = "",
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host = "", max_renames = 12):
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servicetype = None, port = None, TXT = None, domain = "",
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host = "", max_renames = 32768):
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self.interface = interface
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self.type = servicetype
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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.error(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
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def __init__(self, name = None, stop_hook=None, config={}):
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def __init__(self, name = None, stop_hook=None, config=None):
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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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logger.debug(u"Creating client %r", self.name)
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# Uppercase and remove spaces from fingerprint for later
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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:
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sf = open(config["secfile"])
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self.secret = sf.read()
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secfile = open(config["secfile"])
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self.secret = secfile.read()
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raise TypeError(u"No secret or secfile for client %s"
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self.fqdn = config.get("fqdn", "")
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self.host = config.get("host", "")
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self.created = datetime.datetime.now()
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self.last_checked_ok = None
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self.timeout = string_to_delta(config["timeout"])
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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.
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if hasattr(self, "secret") and self.secret:
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logger.info(u"Stopping client %s", self.name)
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self.secret = None
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if self.checker is None:
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# In case check_command has exactly one % operator
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command = self.check_command % self.fqdn
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command = self.check_command % self.host
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except TypeError:
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# Escape attributes for the shell
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escaped_attrs = dict((key, re.escape(str(val)))
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logger.info(u"Starting checker %r for %s",
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command, self.name)
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# We don't need to redirect stdout and stderr, since
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# in normal mode, that is already done by daemon(),
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# and in debug mode we don't want to. (Stdin is
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# 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)
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except subprocess.OSError, error:
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except OSError, error:
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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
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if getattr(self, "checker", None) is None:
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logger.debug("Stopping checker for %(name)s", vars(self))
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logger.debug(u"Stopping checker for %(name)s", vars(self))
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os.kill(self.checker.pid, signal.SIGTERM)
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gnutls.library.functions.gnutls_openpgp_crt_import\
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(crt, ctypes.byref(datum),
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gnutls.library.constants.GNUTLS_OPENPGP_FMT_RAW)
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# Verify the self signature in the key
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crtverify = ctypes.c_uint()
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gnutls.library.functions.gnutls_openpgp_crt_verify_self\
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(crt, 0, ctypes.byref(crtverify))
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if crtverify.value != 0:
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gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
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raise gnutls.errors.CertificateSecurityError("Verify failed")
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# New buffer for the fingerprint
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buffer = ctypes.create_string_buffer(20)
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buffer_length = ctypes.c_size_t()
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buf = ctypes.create_string_buffer(20)
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buf_len = ctypes.c_size_t()
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# Get the fingerprint from the certificate into the buffer
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gnutls.library.functions.gnutls_openpgp_crt_get_fingerprint\
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(crt, ctypes.byref(buffer), ctypes.byref(buffer_length))
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(crt, ctypes.byref(buf), ctypes.byref(buf_len))
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# Deinit the certificate
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gnutls.library.functions.gnutls_openpgp_crt_deinit(crt)
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# Convert the buffer to a Python bytestring
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fpr = ctypes.string_at(buffer, buffer_length.value)
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fpr = ctypes.string_at(buf, buf_len.value)
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# Convert the bytestring to hexadecimal notation
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hex_fpr = u''.join(u"%02X" % ord(char) for char in fpr)
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class tcp_handler(SocketServer.BaseRequestHandler, object):
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class TCP_handler(SocketServer.BaseRequestHandler, object):
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"""A TCP request handler class.
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Instantiated by IPv6_TCPServer for each request to handle it.
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Note: This will run in its own forked process."""
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if self.server.settings["priority"]:
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priority = self.server.settings["priority"]
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gnutls.library.functions.gnutls_priority_set_direct\
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(session._c_object, priority, None);
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(session._c_object, priority, None)
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session.handshake()
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settings: Server settings
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clients: Set() of Client objects
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enabled: Boolean; whether this server is activated yet
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address_family = socket.AF_INET6
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def __init__(self, *args, **kwargs):
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if "clients" in kwargs:
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self.clients = kwargs["clients"]
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del kwargs["clients"]
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return super(type(self), self).__init__(*args, **kwargs)
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super(IPv6_TCPServer, self).__init__(*args, **kwargs)
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def server_bind(self):
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"""This overrides the normal server_bind() function
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to bind to an interface if one was specified, and also NOT to
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in6addr_any = "::"
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self.server_address = (in6addr_any,
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self.server_address[1])
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elif self.server_address[1] is None:
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elif not self.server_address[1]:
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self.server_address = (self.server_address[0],
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return super(type(self), self).server_bind()
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# if self.settings["interface"]:
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# self.server_address = (self.server_address[0],
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return super(IPv6_TCPServer, self).server_bind()
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def server_activate(self):
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return super(IPv6_TCPServer, self).server_activate()
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def string_to_delta(interval):
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datetime.timedelta(1)
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>>> string_to_delta(u'1w')
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datetime.timedelta(7)
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>>> string_to_delta('5m 30s')
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datetime.timedelta(0, 330)
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suffix=unicode(interval[-1])
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value=int(interval[:-1])
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delta = datetime.timedelta(value)
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delta = datetime.timedelta(0, value)
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delta = datetime.timedelta(0, 0, 0, 0, value)
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delta = datetime.timedelta(0, 0, 0, 0, 0, value)
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delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
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timevalue = datetime.timedelta(0)
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for s in interval.split():
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suffix = unicode(s[-1])
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delta = datetime.timedelta(value)
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delta = datetime.timedelta(0, value)
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delta = datetime.timedelta(0, 0, 0, 0, value)
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delta = datetime.timedelta(0, 0, 0, 0, 0, value)
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delta = datetime.timedelta(0, 0, 0, 0, 0, 0, value)
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except (ValueError, IndexError):
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except (ValueError, IndexError):
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def server_state_changed(state):
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"""Derived from the Avahi example code"""
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if state == avahi.SERVER_COLLISION:
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logger.error(u"Server name collision")
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logger.error(u"Zeroconf server name collision")
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elif state == avahi.SERVER_RUNNING:
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def entry_group_state_changed(state, error):
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"""Derived from the Avahi example code"""
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logger.debug(u"state change: %i", state)
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logger.debug(u"Avahi state change: %i", state)
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if state == avahi.ENTRY_GROUP_ESTABLISHED:
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logger.debug(u"Service established.")
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logger.debug(u"Zeroconf service established.")
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elif state == avahi.ENTRY_GROUP_COLLISION:
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logger.warning(u"Service name collision.")
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logger.warning(u"Zeroconf service name collision.")
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elif state == avahi.ENTRY_GROUP_FAILURE:
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logger.critical(u"Error in group state changed %s",
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logger.critical(u"Avahi: Error in group state changed %s",
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raise AvahiGroupError("State changed: %s", str(error))
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"""Call the C function if_nametoindex(), or equivalent"""
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global if_nametoindex
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if "ctypes.util" not in sys.modules:
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if_nametoindex = ctypes.cdll.LoadLibrary\
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(ctypes.util.find_library("c")).if_nametoindex
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except (OSError, AttributeError):
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return if_nametoindex(interface)
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def daemon(nochdir, noclose):
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def daemon(nochdir = False, noclose = False):
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"""See daemon(3). Standard BSD Unix function.
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This should really exist as os.daemon, but it doesn't (yet)."""
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global main_loop_started
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main_loop_started = False
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parser = OptionParser()
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parser = OptionParser(version = "%%prog %s" % version)
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parser.add_option("-i", "--interface", type="string",
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metavar="IF", help="Bind to interface IF")
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parser.add_option("-a", "--address", type="string",
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help="Port number to receive requests on")
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parser.add_option("--check", action="store_true", default=False,
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help="Run self-test")
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parser.add_option("--debug", action="store_true", default=False,
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parser.add_option("--debug", action="store_true",
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help="Debug mode; run in foreground and log to"
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parser.add_option("--priority", type="string", help="GnuTLS"
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default="/etc/mandos", metavar="DIR",
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help="Directory to search for configuration"
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(options, args) = parser.parse_args()
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options = parser.parse_args()[0]
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if options.check:
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# Parse config file for server-global settings
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server_config = ConfigParser.SafeConfigParser(server_defaults)
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del server_defaults
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server_config.read(os.path.join(options.configdir, "server.conf"))
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server_section = "server"
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server_config.read(os.path.join(options.configdir, "mandos.conf"))
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# Convert the SafeConfigParser object to a dict
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server_settings = dict(server_config.items(server_section))
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server_settings = server_config.defaults()
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# Use getboolean on the boolean config option
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server_settings["debug"] = server_config.getboolean\
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(server_section, "debug")
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del server_config
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# Override the settings from the config file with command line
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# Now we have our good server settings in "server_settings"
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debug = server_settings["debug"]
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syslogger.setLevel(logging.WARNING)
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console.setLevel(logging.WARNING)
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if server_settings["servicename"] != "Mandos":
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syslogger.setFormatter(logging.Formatter\
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('Mandos (%s): %%(levelname)s:'
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% server_settings["servicename"]))
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# Parse config file with clients
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client_defaults = { "timeout": "1h",
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"interval": "5m",
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"checker": "fping -q -- %%(fqdn)s",
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"checker": "fping -q -- %(host)s",
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client_config = ConfigParser.SafeConfigParser(client_defaults)
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client_config.read(os.path.join(server_settings["configdir"],
768
tcp_server = IPv6_TCPServer((server_settings["address"],
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server_settings["port"]),
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settings=server_settings,
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pidfilename = "/var/run/mandos.pid"
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pidfile = open(pidfilename, "w")
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except IOError, error:
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logger.error("Could not open file %r", pidfilename)
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uid = pwd.getpwnam("mandos").pw_uid
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uid = pwd.getpwnam("nobody").pw_uid
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gid = pwd.getpwnam("mandos").pw_gid
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gid = pwd.getpwnam("nogroup").pw_gid
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except OSError, error:
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if error[0] != errno.EPERM:
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service = AvahiService(name = server_settings["servicename"],
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type = "_mandos._tcp", );
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servicetype = "_mandos._tcp", )
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if server_settings["interface"]:
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service.interface = if_nametoindex(server_settings["interface"])
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service.interface = if_nametoindex\
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(server_settings["interface"])
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DBusGMainLoop(set_as_default=True )
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main_loop = gobject.MainLoop()
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bus = dbus.SystemBus()
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server = dbus.Interface(
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bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
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avahi.DBUS_INTERFACE_SERVER )
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server = dbus.Interface(bus.get_object(avahi.DBUS_NAME,
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avahi.DBUS_PATH_SERVER),
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avahi.DBUS_INTERFACE_SERVER)
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# End of Avahi example code
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debug = server_settings["debug"]
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console = logging.StreamHandler()
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# console.setLevel(logging.DEBUG)
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console.setFormatter(logging.Formatter\
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('%(levelname)s: %(message)s'))
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logger.addHandler(console)
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def remove_from_clients(client):
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clients.remove(client)
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= dict(client_config.items(section)))
762
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for section in client_config.sections()))
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logger.critical(u"No clients defined")
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# Redirect stdin so all checkers get /dev/null
838
null = os.open(os.path.devnull, os.O_NOCTTY | os.O_RDWR)
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os.dup2(null, sys.stdin.fileno())
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logger.removeHandler(console)
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# Close all input and output, do double fork, etc.
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pidfile.write(str(pid) + "\n")
854
logger.error(u"Could not write to file %r with PID %d",
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# "pidfile" was never created
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"Cleanup function; run on exit"
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for client in clients:
791
tcp_server = IPv6_TCPServer((server_settings["address"],
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server_settings["port"]),
794
settings=server_settings,
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tcp_server.server_activate()
796
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# Find out what port we got
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service.port = tcp_server.socket.getsockname()[1]
798
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logger.info(u"Now listening on address %r, port %d, flowinfo %d,"
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907
tcp_server.handle_request\
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(*args[2:], **kwargs) or True)
818
logger.debug("Starting main loop")
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main_loop_started = True
910
logger.debug(u"Starting main loop")
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except AvahiError, error:
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logger.critical(u"AvahiError: %s" + unicode(error))