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""" Multicast DNS Service Discovery for Python, v0.12
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Copyright (C) 2003, Paul Scott-Murphy
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This module provides a framework for the use of DNS Service Discovery
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using IP multicast. It has been tested against the JRendezvous
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implementation from <a href="http://strangeberry.com">StrangeBerry</a>,
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and against the mDNSResponder from Mac OS X 10.3.8.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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"""
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"""0.12 update - allow selection of binding interface
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typo fix - Thanks A. M. Kuchlingi
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removed all use of word 'Rendezvous' - this is an API change"""
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"""0.11 update - correction to comments for addListener method
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support for new record types seen from OS X
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- IPv6 address
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- hostinfo
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ignore unknown DNS record types
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fixes to name decoding
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works alongside other processes using port 5353 (e.g. on Mac OS X)
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tested against Mac OS X 10.3.2's mDNSResponder
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corrections to removal of list entries for service browser"""
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"""0.10 update - Jonathon Paisley contributed these corrections:
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always multicast replies, even when query is unicast
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correct a pointer encoding problem
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can now write records in any order
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traceback shown on failure
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better TXT record parsing
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server is now separate from name
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can cancel a service browser
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modified some unit tests to accommodate these changes"""
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"""0.09 update - remove all records on service unregistration
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fix DOS security problem with readName"""
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"""0.08 update - changed licensing to LGPL"""
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"""0.07 update - faster shutdown on engine
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pointer encoding of outgoing names
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ServiceBrowser now works
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new unit tests"""
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"""0.06 update - small improvements with unit tests
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added defined exception types
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new style objects
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fixed hostname/interface problem
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fixed socket timeout problem
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fixed addServiceListener() typo bug
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using select() for socket reads
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tested on Debian unstable with Python 2.2.2"""
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"""0.05 update - ensure case insensitivty on domain names
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support for unicast DNS queries"""
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"""0.04 update - added some unit tests
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added __ne__ adjuncts where required
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ensure names end in '.local.'
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timeout on receiving socket for clean shutdown"""
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__author__ = "Paul Scott-Murphy"
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__email__ = "paul at scott dash murphy dot com"
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__version__ = "0.12"
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import string
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import time
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import struct
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import socket
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import threading
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import select
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import traceback
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__all__ = ["Zeroconf", "ServiceInfo", "ServiceBrowser"]
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# hook for threads
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globals()['_GLOBAL_DONE'] = 0
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# Some timing constants
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_UNREGISTER_TIME = 125
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_CHECK_TIME = 175
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_REGISTER_TIME = 225
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_LISTENER_TIME = 200
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_BROWSER_TIME = 500
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# Some DNS constants
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_MDNS_ADDR = '224.0.0.251'
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_MDNS_PORT = 5353;
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_DNS_PORT = 53;
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_DNS_TTL = 60 * 60; # one hour default TTL
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_MAX_MSG_TYPICAL = 1460 # unused
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_MAX_MSG_ABSOLUTE = 8972
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_FLAGS_QR_MASK = 0x8000 # query response mask
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_FLAGS_QR_QUERY = 0x0000 # query
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_FLAGS_QR_RESPONSE = 0x8000 # response
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_FLAGS_AA = 0x0400 # Authorative answer
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_FLAGS_TC = 0x0200 # Truncated
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_FLAGS_RD = 0x0100 # Recursion desired
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_FLAGS_RA = 0x8000 # Recursion available
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_FLAGS_Z = 0x0040 # Zero
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_FLAGS_AD = 0x0020 # Authentic data
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_FLAGS_CD = 0x0010 # Checking disabled
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_CLASS_IN = 1
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_CLASS_CS = 2
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_CLASS_CH = 3
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_CLASS_HS = 4
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_CLASS_NONE = 254
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_CLASS_ANY = 255
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_CLASS_MASK = 0x7FFF
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_CLASS_UNIQUE = 0x8000
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_TYPE_A = 1
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_TYPE_NS = 2
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_TYPE_MD = 3
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_TYPE_MF = 4
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_TYPE_CNAME = 5
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_TYPE_SOA = 6
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_TYPE_MB = 7
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_TYPE_MG = 8
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_TYPE_MR = 9
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_TYPE_NULL = 10
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_TYPE_WKS = 11
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_TYPE_PTR = 12
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_TYPE_HINFO = 13
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_TYPE_MINFO = 14
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_TYPE_MX = 15
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_TYPE_TXT = 16
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_TYPE_AAAA = 28
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_TYPE_SRV = 33
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_TYPE_ANY = 255
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# Mapping constants to names
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_CLASSES = { _CLASS_IN : "in",
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_CLASS_CS : "cs",
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_CLASS_CH : "ch",
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_CLASS_HS : "hs",
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_CLASS_NONE : "none",
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_CLASS_ANY : "any" }
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_TYPES = { _TYPE_A : "a",
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_TYPE_NS : "ns",
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_TYPE_MD : "md",
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_TYPE_MF : "mf",
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_TYPE_CNAME : "cname",
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_TYPE_SOA : "soa",
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_TYPE_MB : "mb",
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_TYPE_MG : "mg",
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_TYPE_MR : "mr",
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_TYPE_NULL : "null",
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_TYPE_WKS : "wks",
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_TYPE_PTR : "ptr",
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_TYPE_HINFO : "hinfo",
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_TYPE_MINFO : "minfo",
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_TYPE_MX : "mx",
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_TYPE_TXT : "txt",
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_TYPE_AAAA : "quada",
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_TYPE_SRV : "srv",
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_TYPE_ANY : "any" }
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# utility functions
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def currentTimeMillis():
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"""Current system time in milliseconds"""
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return time.time() * 1000
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# Exceptions
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class NonLocalNameException(Exception):
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pass
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class NonUniqueNameException(Exception):
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pass
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class NamePartTooLongException(Exception):
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pass
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class AbstractMethodException(Exception):
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pass
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class BadTypeInNameException(Exception):
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pass
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# implementation classes
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class DNSEntry(object):
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"""A DNS entry"""
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def __init__(self, name, type, clazz):
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self.key = string.lower(name)
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self.name = name
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self.type = type
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self.clazz = clazz & _CLASS_MASK
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self.unique = (clazz & _CLASS_UNIQUE) != 0
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def __eq__(self, other):
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"""Equality test on name, type, and class"""
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if isinstance(other, DNSEntry):
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return self.name == other.name and self.type == other.type and self.clazz == other.clazz
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return 0
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def __ne__(self, other):
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"""Non-equality test"""
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return not self.__eq__(other)
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def getClazz(self, clazz):
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"""Class accessor"""
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try:
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return _CLASSES[clazz]
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except:
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return "?(%s)" % (clazz)
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def getType(self, type):
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"""Type accessor"""
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try:
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return _TYPES[type]
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except:
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return "?(%s)" % (type)
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def toString(self, hdr, other):
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"""String representation with additional information"""
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result = "%s[%s,%s" % (hdr, self.getType(self.type), self.getClazz(self.clazz))
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if self.unique:
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result += "-unique,"
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else:
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result += ","
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result += self.name
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if other is not None:
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result += ",%s]" % (other)
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else:
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result += "]"
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return result
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class DNSQuestion(DNSEntry):
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"""A DNS question entry"""
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def __init__(self, name, type, clazz):
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if not name.endswith(".local."):
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raise NonLocalNameException
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DNSEntry.__init__(self, name, type, clazz)
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def answeredBy(self, rec):
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"""Returns true if the question is answered by the record"""
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return self.clazz == rec.clazz and (self.type == rec.type or self.type == _TYPE_ANY) and self.name == rec.name
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def __repr__(self):
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"""String representation"""
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return DNSEntry.toString(self, "question", None)
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class DNSRecord(DNSEntry):
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"""A DNS record - like a DNS entry, but has a TTL"""
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def __init__(self, name, type, clazz, ttl):
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DNSEntry.__init__(self, name, type, clazz)
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self.ttl = ttl
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self.created = currentTimeMillis()
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def __eq__(self, other):
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"""Tests equality as per DNSRecord"""
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if isinstance(other, DNSRecord):
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return DNSEntry.__eq__(self, other)
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return 0
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def suppressedBy(self, msg):
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"""Returns true if any answer in a message can suffice for the
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information held in this record."""
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for record in msg.answers:
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if self.suppressedByAnswer(record):
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return 1
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return 0
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def suppressedByAnswer(self, other):
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"""Returns true if another record has same name, type and class,
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and if its TTL is at least half of this record's."""
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if self == other and other.ttl > (self.ttl / 2):
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return 1
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return 0
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def getExpirationTime(self, percent):
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"""Returns the time at which this record will have expired
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by a certain percentage."""
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return self.created + (percent * self.ttl * 10)
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def getRemainingTTL(self, now):
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"""Returns the remaining TTL in seconds."""
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return max(0, (self.getExpirationTime(100) - now) / 1000)
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def isExpired(self, now):
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"""Returns true if this record has expired."""
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return self.getExpirationTime(100) <= now
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def isStale(self, now):
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"""Returns true if this record is at least half way expired."""
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return self.getExpirationTime(50) <= now
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def resetTTL(self, other):
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"""Sets this record's TTL and created time to that of
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another record."""
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self.created = other.created
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self.ttl = other.ttl
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def write(self, out):
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"""Abstract method"""
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raise AbstractMethodException
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def toString(self, other):
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"""String representation with addtional information"""
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arg = "%s/%s,%s" % (self.ttl, self.getRemainingTTL(currentTimeMillis()), other)
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return DNSEntry.toString(self, "record", arg)
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class DNSAddress(DNSRecord):
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"""A DNS address record"""
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def __init__(self, name, type, clazz, ttl, address):
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DNSRecord.__init__(self, name, type, clazz, ttl)
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self.address = address
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def write(self, out):
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"""Used in constructing an outgoing packet"""
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out.writeString(self.address, len(self.address))
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def __eq__(self, other):
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"""Tests equality on address"""
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if isinstance(other, DNSAddress):
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return self.address == other.address
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return 0
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def __repr__(self):
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"""String representation"""
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try:
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return socket.inet_ntoa(self.address)
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except:
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return self.address
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class DNSHinfo(DNSRecord):
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"""A DNS host information record"""
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def __init__(self, name, type, clazz, ttl, cpu, os):
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DNSRecord.__init__(self, name, type, clazz, ttl)
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self.cpu = cpu
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self.os = os
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def write(self, out):
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"""Used in constructing an outgoing packet"""
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out.writeString(self.cpu, len(self.cpu))
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out.writeString(self.os, len(self.os))
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def __eq__(self, other):
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"""Tests equality on cpu and os"""
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if isinstance(other, DNSHinfo):
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return self.cpu == other.cpu and self.os == other.os
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return 0
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|
378 |
def __repr__(self):
|
|
|
379 |
"""String representation"""
|
|
|
380 |
return self.cpu + " " + self.os
|
|
|
381 |
|
|
|
382 |
class DNSPointer(DNSRecord):
|
|
|
383 |
"""A DNS pointer record"""
|
|
|
384 |
|
|
|
385 |
def __init__(self, name, type, clazz, ttl, alias):
|
|
|
386 |
DNSRecord.__init__(self, name, type, clazz, ttl)
|
|
|
387 |
self.alias = alias
|
|
|
388 |
|
|
|
389 |
def write(self, out):
|
|
|
390 |
"""Used in constructing an outgoing packet"""
|
|
|
391 |
out.writeName(self.alias)
|
|
|
392 |
|
|
|
393 |
def __eq__(self, other):
|
|
|
394 |
"""Tests equality on alias"""
|
|
|
395 |
if isinstance(other, DNSPointer):
|
|
|
396 |
return self.alias == other.alias
|
|
|
397 |
return 0
|
|
|
398 |
|
|
|
399 |
def __repr__(self):
|
|
|
400 |
"""String representation"""
|
|
|
401 |
return self.toString(self.alias)
|
|
|
402 |
|
|
|
403 |
class DNSText(DNSRecord):
|
|
|
404 |
"""A DNS text record"""
|
|
|
405 |
|
|
|
406 |
def __init__(self, name, type, clazz, ttl, text):
|
|
|
407 |
DNSRecord.__init__(self, name, type, clazz, ttl)
|
|
|
408 |
self.text = text
|
|
|
409 |
|
|
|
410 |
def write(self, out):
|
|
|
411 |
"""Used in constructing an outgoing packet"""
|
|
|
412 |
out.writeString(self.text, len(self.text))
|
|
|
413 |
|
|
|
414 |
def __eq__(self, other):
|
|
|
415 |
"""Tests equality on text"""
|
|
|
416 |
if isinstance(other, DNSText):
|
|
|
417 |
return self.text == other.text
|
|
|
418 |
return 0
|
|
|
419 |
|
|
|
420 |
def __repr__(self):
|
|
|
421 |
"""String representation"""
|
|
|
422 |
if len(self.text) > 10:
|
|
|
423 |
return self.toString(self.text[:7] + "...")
|
|
|
424 |
else:
|
|
|
425 |
return self.toString(self.text)
|
|
|
426 |
|
|
|
427 |
class DNSService(DNSRecord):
|
|
|
428 |
"""A DNS service record"""
|
|
|
429 |
|
|
|
430 |
def __init__(self, name, type, clazz, ttl, priority, weight, port, server):
|
|
|
431 |
DNSRecord.__init__(self, name, type, clazz, ttl)
|
|
|
432 |
self.priority = priority
|
|
|
433 |
self.weight = weight
|
|
|
434 |
self.port = port
|
|
|
435 |
self.server = server
|
|
|
436 |
|
|
|
437 |
def write(self, out):
|
|
|
438 |
"""Used in constructing an outgoing packet"""
|
|
|
439 |
out.writeShort(self.priority)
|
|
|
440 |
out.writeShort(self.weight)
|
|
|
441 |
out.writeShort(self.port)
|
|
|
442 |
out.writeName(self.server)
|
|
|
443 |
|
|
|
444 |
def __eq__(self, other):
|
|
|
445 |
"""Tests equality on priority, weight, port and server"""
|
|
|
446 |
if isinstance(other, DNSService):
|
|
|
447 |
return self.priority == other.priority and self.weight == other.weight and self.port == other.port and self.server == other.server
|
|
|
448 |
return 0
|
|
|
449 |
|
|
|
450 |
def __repr__(self):
|
|
|
451 |
"""String representation"""
|
|
|
452 |
return self.toString("%s:%s" % (self.server, self.port))
|
|
|
453 |
|
|
|
454 |
class DNSIncoming(object):
|
|
|
455 |
"""Object representation of an incoming DNS packet"""
|
|
|
456 |
|
|
|
457 |
def __init__(self, data):
|
|
|
458 |
"""Constructor from string holding bytes of packet"""
|
|
|
459 |
self.offset = 0
|
|
|
460 |
self.data = data
|
|
|
461 |
self.questions = []
|
|
|
462 |
self.answers = []
|
|
|
463 |
self.numQuestions = 0
|
|
|
464 |
self.numAnswers = 0
|
|
|
465 |
self.numAuthorities = 0
|
|
|
466 |
self.numAdditionals = 0
|
|
|
467 |
|
|
|
468 |
self.readHeader()
|
|
|
469 |
self.readQuestions()
|
|
|
470 |
self.readOthers()
|
|
|
471 |
|
|
|
472 |
def readHeader(self):
|
|
|
473 |
"""Reads header portion of packet"""
|
|
|
474 |
format = '!HHHHHH'
|
|
|
475 |
length = struct.calcsize(format)
|
|
|
476 |
info = struct.unpack(format, self.data[self.offset:self.offset+length])
|
|
|
477 |
self.offset += length
|
|
|
478 |
|
|
|
479 |
self.id = info[0]
|
|
|
480 |
self.flags = info[1]
|
|
|
481 |
self.numQuestions = info[2]
|
|
|
482 |
self.numAnswers = info[3]
|
|
|
483 |
self.numAuthorities = info[4]
|
|
|
484 |
self.numAdditionals = info[5]
|
|
|
485 |
|
|
|
486 |
def readQuestions(self):
|
|
|
487 |
"""Reads questions section of packet"""
|
|
|
488 |
format = '!HH'
|
|
|
489 |
length = struct.calcsize(format)
|
|
|
490 |
for i in range(0, self.numQuestions):
|
|
|
491 |
name = self.readName()
|
|
|
492 |
info = struct.unpack(format, self.data[self.offset:self.offset+length])
|
|
|
493 |
self.offset += length
|
|
|
494 |
|
|
|
495 |
question = DNSQuestion(name, info[0], info[1])
|
|
|
496 |
self.questions.append(question)
|
|
|
497 |
|
|
|
498 |
def readInt(self):
|
|
|
499 |
"""Reads an integer from the packet"""
|
|
|
500 |
format = '!I'
|
|
|
501 |
length = struct.calcsize(format)
|
|
|
502 |
info = struct.unpack(format, self.data[self.offset:self.offset+length])
|
|
|
503 |
self.offset += length
|
|
|
504 |
return info[0]
|
|
|
505 |
|
|
|
506 |
def readCharacterString(self):
|
|
|
507 |
"""Reads a character string from the packet"""
|
|
|
508 |
length = ord(self.data[self.offset])
|
|
|
509 |
self.offset += 1
|
|
|
510 |
return self.readString(length)
|
|
|
511 |
|
|
|
512 |
def readString(self, len):
|
|
|
513 |
"""Reads a string of a given length from the packet"""
|
|
|
514 |
format = '!' + str(len) + 's'
|
|
|
515 |
length = struct.calcsize(format)
|
|
|
516 |
info = struct.unpack(format, self.data[self.offset:self.offset+length])
|
|
|
517 |
self.offset += length
|
|
|
518 |
return info[0]
|
|
|
519 |
|
|
|
520 |
def readUnsignedShort(self):
|
|
|
521 |
"""Reads an unsigned short from the packet"""
|
|
|
522 |
format = '!H'
|
|
|
523 |
length = struct.calcsize(format)
|
|
|
524 |
info = struct.unpack(format, self.data[self.offset:self.offset+length])
|
|
|
525 |
self.offset += length
|
|
|
526 |
return info[0]
|
|
|
527 |
|
|
|
528 |
def readOthers(self):
|
|
|
529 |
"""Reads the answers, authorities and additionals section of the packet"""
|
|
|
530 |
format = '!HHiH'
|
|
|
531 |
length = struct.calcsize(format)
|
|
|
532 |
n = self.numAnswers + self.numAuthorities + self.numAdditionals
|
|
|
533 |
for i in range(0, n):
|
|
|
534 |
domain = self.readName()
|
|
|
535 |
info = struct.unpack(format, self.data[self.offset:self.offset+length])
|
|
|
536 |
self.offset += length
|
|
|
537 |
|
|
|
538 |
rec = None
|
|
|
539 |
if info[0] == _TYPE_A:
|
|
|
540 |
rec = DNSAddress(domain, info[0], info[1], info[2], self.readString(4))
|
|
|
541 |
elif info[0] == _TYPE_CNAME or info[0] == _TYPE_PTR:
|
|
|
542 |
rec = DNSPointer(domain, info[0], info[1], info[2], self.readName())
|
|
|
543 |
elif info[0] == _TYPE_TXT:
|
|
|
544 |
rec = DNSText(domain, info[0], info[1], info[2], self.readString(info[3]))
|
|
|
545 |
elif info[0] == _TYPE_SRV:
|
|
|
546 |
rec = DNSService(domain, info[0], info[1], info[2], self.readUnsignedShort(), self.readUnsignedShort(), self.readUnsignedShort(), self.readName())
|
|
|
547 |
elif info[0] == _TYPE_HINFO:
|
|
|
548 |
rec = DNSHinfo(domain, info[0], info[1], info[2], self.readCharacterString(), self.readCharacterString())
|
|
|
549 |
elif info[0] == _TYPE_AAAA:
|
|
|
550 |
rec = DNSAddress(domain, info[0], info[1], info[2], self.readString(16))
|
|
|
551 |
else:
|
|
|
552 |
# Try to ignore types we don't know about
|
|
|
553 |
# this may mean the rest of the name is
|
|
|
554 |
# unable to be parsed, and may show errors
|
|
|
555 |
# so this is left for debugging. New types
|
|
|
556 |
# encountered need to be parsed properly.
|
|
|
557 |
#
|
|
|
558 |
#print "UNKNOWN TYPE = " + str(info[0])
|
|
|
559 |
#raise BadTypeInNameException
|
|
|
560 |
pass
|
|
|
561 |
|
|
|
562 |
if rec is not None:
|
|
|
563 |
self.answers.append(rec)
|
|
|
564 |
|
|
|
565 |
def isQuery(self):
|
|
|
566 |
"""Returns true if this is a query"""
|
|
|
567 |
return (self.flags & _FLAGS_QR_MASK) == _FLAGS_QR_QUERY
|
|
|
568 |
|
|
|
569 |
def isResponse(self):
|
|
|
570 |
"""Returns true if this is a response"""
|
|
|
571 |
return (self.flags & _FLAGS_QR_MASK) == _FLAGS_QR_RESPONSE
|
|
|
572 |
|
|
|
573 |
def readUTF(self, offset, len):
|
|
|
574 |
"""Reads a UTF-8 string of a given length from the packet"""
|
|
|
575 |
result = self.data[offset:offset+len].decode('utf-8')
|
|
|
576 |
return result
|
|
|
577 |
|
|
|
578 |
def readName(self):
|
|
|
579 |
"""Reads a domain name from the packet"""
|
|
|
580 |
result = ''
|
|
|
581 |
off = self.offset
|
|
|
582 |
next = -1
|
|
|
583 |
first = off
|
|
|
584 |
|
|
|
585 |
while 1:
|
|
|
586 |
len = ord(self.data[off])
|
|
|
587 |
off += 1
|
|
|
588 |
if len == 0:
|
|
|
589 |
break
|
|
|
590 |
t = len & 0xC0
|
|
|
591 |
if t == 0x00:
|
|
|
592 |
result = ''.join((result, self.readUTF(off, len) + '.'))
|
|
|
593 |
off += len
|
|
|
594 |
elif t == 0xC0:
|
|
|
595 |
if next < 0:
|
|
|
596 |
next = off + 1
|
|
|
597 |
off = ((len & 0x3F) << 8) | ord(self.data[off])
|
|
|
598 |
if off >= first:
|
|
|
599 |
raise "Bad domain name (circular) at " + str(off)
|
|
|
600 |
first = off
|
|
|
601 |
else:
|
|
|
602 |
raise "Bad domain name at " + str(off)
|
|
|
603 |
|
|
|
604 |
if next >= 0:
|
|
|
605 |
self.offset = next
|
|
|
606 |
else:
|
|
|
607 |
self.offset = off
|
|
|
608 |
|
|
|
609 |
return result
|
|
|
610 |
|
|
|
611 |
|
|
|
612 |
class DNSOutgoing(object):
|
|
|
613 |
"""Object representation of an outgoing packet"""
|
|
|
614 |
|
|
|
615 |
def __init__(self, flags, multicast = 1):
|
|
|
616 |
self.finished = 0
|
|
|
617 |
self.id = 0
|
|
|
618 |
self.multicast = multicast
|
|
|
619 |
self.flags = flags
|
|
|
620 |
self.names = {}
|
|
|
621 |
self.data = []
|
|
|
622 |
self.size = 12
|
|
|
623 |
|
|
|
624 |
self.questions = []
|
|
|
625 |
self.answers = []
|
|
|
626 |
self.authorities = []
|
|
|
627 |
self.additionals = []
|
|
|
628 |
|
|
|
629 |
def addQuestion(self, record):
|
|
|
630 |
"""Adds a question"""
|
|
|
631 |
self.questions.append(record)
|
|
|
632 |
|
|
|
633 |
def addAnswer(self, inp, record):
|
|
|
634 |
"""Adds an answer"""
|
|
|
635 |
if not record.suppressedBy(inp):
|
|
|
636 |
self.addAnswerAtTime(record, 0)
|
|
|
637 |
|
|
|
638 |
def addAnswerAtTime(self, record, now):
|
|
|
639 |
"""Adds an answer if if does not expire by a certain time"""
|
|
|
640 |
if record is not None:
|
|
|
641 |
if now == 0 or not record.isExpired(now):
|
|
|
642 |
self.answers.append((record, now))
|
|
|
643 |
|
|
|
644 |
def addAuthorativeAnswer(self, record):
|
|
|
645 |
"""Adds an authoritative answer"""
|
|
|
646 |
self.authorities.append(record)
|
|
|
647 |
|
|
|
648 |
def addAdditionalAnswer(self, record):
|
|
|
649 |
"""Adds an additional answer"""
|
|
|
650 |
self.additionals.append(record)
|
|
|
651 |
|
|
|
652 |
def writeByte(self, value):
|
|
|
653 |
"""Writes a single byte to the packet"""
|
|
|
654 |
format = '!c'
|
|
|
655 |
self.data.append(struct.pack(format, chr(value)))
|
|
|
656 |
self.size += 1
|
|
|
657 |
|
|
|
658 |
def insertShort(self, index, value):
|
|
|
659 |
"""Inserts an unsigned short in a certain position in the packet"""
|
|
|
660 |
format = '!H'
|
|
|
661 |
self.data.insert(index, struct.pack(format, value))
|
|
|
662 |
self.size += 2
|
|
|
663 |
|
|
|
664 |
def writeShort(self, value):
|
|
|
665 |
"""Writes an unsigned short to the packet"""
|
|
|
666 |
format = '!H'
|
|
|
667 |
self.data.append(struct.pack(format, value))
|
|
|
668 |
self.size += 2
|
|
|
669 |
|
|
|
670 |
def writeInt(self, value):
|
|
|
671 |
"""Writes an unsigned integer to the packet"""
|
|
|
672 |
format = '!I'
|
|
|
673 |
self.data.append(struct.pack(format, int(value)))
|
|
|
674 |
self.size += 4
|
|
|
675 |
|
|
|
676 |
def writeString(self, value, length):
|
|
|
677 |
"""Writes a string to the packet"""
|
|
|
678 |
format = '!' + str(length) + 's'
|
|
|
679 |
self.data.append(struct.pack(format, value))
|
|
|
680 |
self.size += length
|
|
|
681 |
|
|
|
682 |
def writeUTF(self, s):
|
|
|
683 |
"""Writes a UTF-8 string of a given length to the packet"""
|
|
|
684 |
utfstr = s.encode('utf-8')
|
|
|
685 |
length = len(utfstr)
|
|
|
686 |
if length > 64:
|
|
|
687 |
raise NamePartTooLongException
|
|
|
688 |
self.writeByte(length)
|
|
|
689 |
self.writeString(utfstr, length)
|
|
|
690 |
|
|
|
691 |
def writeName(self, name):
|
|
|
692 |
"""Writes a domain name to the packet"""
|
|
|
693 |
|
|
|
694 |
try:
|
|
|
695 |
# Find existing instance of this name in packet
|
|
|
696 |
#
|
|
|
697 |
index = self.names[name]
|
|
|
698 |
except KeyError:
|
|
|
699 |
# No record of this name already, so write it
|
|
|
700 |
# out as normal, recording the location of the name
|
|
|
701 |
# for future pointers to it.
|
|
|
702 |
#
|
|
|
703 |
self.names[name] = self.size
|
|
|
704 |
parts = name.split('.')
|
|
|
705 |
if parts[-1] == '':
|
|
|
706 |
parts = parts[:-1]
|
|
|
707 |
for part in parts:
|
|
|
708 |
self.writeUTF(part)
|
|
|
709 |
self.writeByte(0)
|
|
|
710 |
return
|
|
|
711 |
|
|
|
712 |
# An index was found, so write a pointer to it
|
|
|
713 |
#
|
|
|
714 |
self.writeByte((index >> 8) | 0xC0)
|
|
|
715 |
self.writeByte(index)
|
|
|
716 |
|
|
|
717 |
def writeQuestion(self, question):
|
|
|
718 |
"""Writes a question to the packet"""
|
|
|
719 |
self.writeName(question.name)
|
|
|
720 |
self.writeShort(question.type)
|
|
|
721 |
self.writeShort(question.clazz)
|
|
|
722 |
|
|
|
723 |
def writeRecord(self, record, now):
|
|
|
724 |
"""Writes a record (answer, authoritative answer, additional) to
|
|
|
725 |
the packet"""
|
|
|
726 |
self.writeName(record.name)
|
|
|
727 |
self.writeShort(record.type)
|
|
|
728 |
if record.unique and self.multicast:
|
|
|
729 |
self.writeShort(record.clazz | _CLASS_UNIQUE)
|
|
|
730 |
else:
|
|
|
731 |
self.writeShort(record.clazz)
|
|
|
732 |
if now == 0:
|
|
|
733 |
self.writeInt(record.ttl)
|
|
|
734 |
else:
|
|
|
735 |
self.writeInt(record.getRemainingTTL(now))
|
|
|
736 |
index = len(self.data)
|
|
|
737 |
# Adjust size for the short we will write before this record
|
|
|
738 |
#
|
|
|
739 |
self.size += 2
|
|
|
740 |
record.write(self)
|
|
|
741 |
self.size -= 2
|
|
|
742 |
|
|
|
743 |
length = len(''.join(self.data[index:]))
|
|
|
744 |
self.insertShort(index, length) # Here is the short we adjusted for
|
|
|
745 |
|
|
|
746 |
def packet(self):
|
|
|
747 |
"""Returns a string containing the packet's bytes
|
|
|
748 |
|
|
|
749 |
No further parts should be added to the packet once this
|
|
|
750 |
is done."""
|
|
|
751 |
if not self.finished:
|
|
|
752 |
self.finished = 1
|
|
|
753 |
for question in self.questions:
|
|
|
754 |
self.writeQuestion(question)
|
|
|
755 |
for answer, time in self.answers:
|
|
|
756 |
self.writeRecord(answer, time)
|
|
|
757 |
for authority in self.authorities:
|
|
|
758 |
self.writeRecord(authority, 0)
|
|
|
759 |
for additional in self.additionals:
|
|
|
760 |
self.writeRecord(additional, 0)
|
|
|
761 |
|
|
|
762 |
self.insertShort(0, len(self.additionals))
|
|
|
763 |
self.insertShort(0, len(self.authorities))
|
|
|
764 |
self.insertShort(0, len(self.answers))
|
|
|
765 |
self.insertShort(0, len(self.questions))
|
|
|
766 |
self.insertShort(0, self.flags)
|
|
|
767 |
if self.multicast:
|
|
|
768 |
self.insertShort(0, 0)
|
|
|
769 |
else:
|
|
|
770 |
self.insertShort(0, self.id)
|
|
|
771 |
return ''.join(self.data)
|
|
|
772 |
|
|
|
773 |
|
|
|
774 |
class DNSCache(object):
|
|
|
775 |
"""A cache of DNS entries"""
|
|
|
776 |
|
|
|
777 |
def __init__(self):
|
|
|
778 |
self.cache = {}
|
|
|
779 |
|
|
|
780 |
def add(self, entry):
|
|
|
781 |
"""Adds an entry"""
|
|
|
782 |
try:
|
|
|
783 |
list = self.cache[entry.key]
|
|
|
784 |
except:
|
|
|
785 |
list = self.cache[entry.key] = []
|
|
|
786 |
list.append(entry)
|
|
|
787 |
|
|
|
788 |
def remove(self, entry):
|
|
|
789 |
"""Removes an entry"""
|
|
|
790 |
try:
|
|
|
791 |
list = self.cache[entry.key]
|
|
|
792 |
list.remove(entry)
|
|
|
793 |
except:
|
|
|
794 |
pass
|
|
|
795 |
|
|
|
796 |
def get(self, entry):
|
|
|
797 |
"""Gets an entry by key. Will return None if there is no
|
|
|
798 |
matching entry."""
|
|
|
799 |
try:
|
|
|
800 |
list = self.cache[entry.key]
|
|
|
801 |
return list[list.index(entry)]
|
|
|
802 |
except:
|
|
|
803 |
return None
|
|
|
804 |
|
|
|
805 |
def getByDetails(self, name, type, clazz):
|
|
|
806 |
"""Gets an entry by details. Will return None if there is
|
|
|
807 |
no matching entry."""
|
|
|
808 |
entry = DNSEntry(name, type, clazz)
|
|
|
809 |
return self.get(entry)
|
|
|
810 |
|
|
|
811 |
def entriesWithName(self, name):
|
|
|
812 |
"""Returns a list of entries whose key matches the name."""
|
|
|
813 |
try:
|
|
|
814 |
return self.cache[name]
|
|
|
815 |
except:
|
|
|
816 |
return []
|
|
|
817 |
|
|
|
818 |
def entries(self):
|
|
|
819 |
"""Returns a list of all entries"""
|
|
|
820 |
def add(x, y): return x+y
|
|
|
821 |
try:
|
|
|
822 |
return reduce(add, self.cache.values())
|
|
|
823 |
except:
|
|
|
824 |
return []
|
|
|
825 |
|
|
|
826 |
|
|
|
827 |
class Engine(threading.Thread):
|
|
|
828 |
"""An engine wraps read access to sockets, allowing objects that
|
|
|
829 |
need to receive data from sockets to be called back when the
|
|
|
830 |
sockets are ready.
|
|
|
831 |
|
|
|
832 |
A reader needs a handle_read() method, which is called when the socket
|
|
|
833 |
it is interested in is ready for reading.
|
|
|
834 |
|
|
|
835 |
Writers are not implemented here, because we only send short
|
|
|
836 |
packets.
|
|
|
837 |
"""
|
|
|
838 |
|
|
|
839 |
def __init__(self, zeroconf):
|
|
|
840 |
threading.Thread.__init__(self)
|
|
|
841 |
self.zeroconf = zeroconf
|
|
|
842 |
self.readers = {} # maps socket to reader
|
|
|
843 |
self.timeout = 5
|
|
|
844 |
self.condition = threading.Condition()
|
|
|
845 |
self.start()
|
|
|
846 |
|
|
|
847 |
def run(self):
|
|
|
848 |
while not globals()['_GLOBAL_DONE']:
|
|
|
849 |
rs = self.getReaders()
|
|
|
850 |
if len(rs) == 0:
|
|
|
851 |
# No sockets to manage, but we wait for the timeout
|
|
|
852 |
# or addition of a socket
|
|
|
853 |
#
|
|
|
854 |
self.condition.acquire()
|
|
|
855 |
self.condition.wait(self.timeout)
|
|
|
856 |
self.condition.release()
|
|
|
857 |
else:
|
|
|
858 |
try:
|
|
|
859 |
rr, wr, er = select.select(rs, [], [], self.timeout)
|
|
|
860 |
for socket in rr:
|
|
|
861 |
try:
|
|
|
862 |
self.readers[socket].handle_read()
|
|
|
863 |
except:
|
|
|
864 |
traceback.print_exc()
|
|
|
865 |
except:
|
|
|
866 |
pass
|
|
|
867 |
|
|
|
868 |
def getReaders(self):
|
|
|
869 |
result = []
|
|
|
870 |
self.condition.acquire()
|
|
|
871 |
result = self.readers.keys()
|
|
|
872 |
self.condition.release()
|
|
|
873 |
return result
|
|
|
874 |
|
|
|
875 |
def addReader(self, reader, socket):
|
|
|
876 |
self.condition.acquire()
|
|
|
877 |
self.readers[socket] = reader
|
|
|
878 |
self.condition.notify()
|
|
|
879 |
self.condition.release()
|
|
|
880 |
|
|
|
881 |
def delReader(self, socket):
|
|
|
882 |
self.condition.acquire()
|
|
|
883 |
del(self.readers[socket])
|
|
|
884 |
self.condition.notify()
|
|
|
885 |
self.condition.release()
|
|
|
886 |
|
|
|
887 |
def notify(self):
|
|
|
888 |
self.condition.acquire()
|
|
|
889 |
self.condition.notify()
|
|
|
890 |
self.condition.release()
|
|
|
891 |
|
|
|
892 |
class Listener(object):
|
|
|
893 |
"""A Listener is used by this module to listen on the multicast
|
|
|
894 |
group to which DNS messages are sent, allowing the implementation
|
|
|
895 |
to cache information as it arrives.
|
|
|
896 |
|
|
|
897 |
It requires registration with an Engine object in order to have
|
|
|
898 |
the read() method called when a socket is availble for reading."""
|
|
|
899 |
|
|
|
900 |
def __init__(self, zeroconf):
|
|
|
901 |
self.zeroconf = zeroconf
|
|
|
902 |
self.zeroconf.engine.addReader(self, self.zeroconf.socket)
|
|
|
903 |
|
|
|
904 |
def handle_read(self):
|
|
|
905 |
data, (addr, port) = self.zeroconf.socket.recvfrom(_MAX_MSG_ABSOLUTE)
|
|
|
906 |
self.data = data
|
|
|
907 |
msg = DNSIncoming(data)
|
|
|
908 |
if msg.isQuery():
|
|
|
909 |
# Always multicast responses
|
|
|
910 |
#
|
|
|
911 |
if port == _MDNS_PORT:
|
|
|
912 |
self.zeroconf.handleQuery(msg, _MDNS_ADDR, _MDNS_PORT)
|
|
|
913 |
# If it's not a multicast query, reply via unicast
|
|
|
914 |
# and multicast
|
|
|
915 |
#
|
|
|
916 |
elif port == _DNS_PORT:
|
|
|
917 |
self.zeroconf.handleQuery(msg, addr, port)
|
|
|
918 |
self.zeroconf.handleQuery(msg, _MDNS_ADDR, _MDNS_PORT)
|
|
|
919 |
else:
|
|
|
920 |
self.zeroconf.handleResponse(msg)
|
|
|
921 |
|
|
|
922 |
|
|
|
923 |
class Reaper(threading.Thread):
|
|
|
924 |
"""A Reaper is used by this module to remove cache entries that
|
|
|
925 |
have expired."""
|
|
|
926 |
|
|
|
927 |
def __init__(self, zeroconf):
|
|
|
928 |
threading.Thread.__init__(self)
|
|
|
929 |
self.zeroconf = zeroconf
|
|
|
930 |
self.start()
|
|
|
931 |
|
|
|
932 |
def run(self):
|
|
|
933 |
while 1:
|
|
|
934 |
self.zeroconf.wait(10 * 1000)
|
|
|
935 |
if globals()['_GLOBAL_DONE']:
|
|
|
936 |
return
|
|
|
937 |
now = currentTimeMillis()
|
|
|
938 |
for record in self.zeroconf.cache.entries():
|
|
|
939 |
if record.isExpired(now):
|
|
|
940 |
self.zeroconf.updateRecord(now, record)
|
|
|
941 |
self.zeroconf.cache.remove(record)
|
|
|
942 |
|
|
|
943 |
|
|
|
944 |
class ServiceBrowser(threading.Thread):
|
|
|
945 |
"""Used to browse for a service of a specific type.
|
|
|
946 |
|
|
|
947 |
The listener object will have its addService() and
|
|
|
948 |
removeService() methods called when this browser
|
|
|
949 |
discovers changes in the services availability."""
|
|
|
950 |
|
|
|
951 |
def __init__(self, zeroconf, type, listener):
|
|
|
952 |
"""Creates a browser for a specific type"""
|
|
|
953 |
threading.Thread.__init__(self)
|
|
|
954 |
self.zeroconf = zeroconf
|
|
|
955 |
self.type = type
|
|
|
956 |
self.listener = listener
|
|
|
957 |
self.services = {}
|
|
|
958 |
self.nextTime = currentTimeMillis()
|
|
|
959 |
self.delay = _BROWSER_TIME
|
|
|
960 |
self.list = []
|
|
|
961 |
|
|
|
962 |
self.done = 0
|
|
|
963 |
|
|
|
964 |
self.zeroconf.addListener(self, DNSQuestion(self.type, _TYPE_PTR, _CLASS_IN))
|
|
|
965 |
self.start()
|
|
|
966 |
|
|
|
967 |
def updateRecord(self, zeroconf, now, record):
|
|
|
968 |
"""Callback invoked by Zeroconf when new information arrives.
|
|
|
969 |
|
|
|
970 |
Updates information required by browser in the Zeroconf cache."""
|
|
|
971 |
if record.type == _TYPE_PTR and record.name == self.type:
|
|
|
972 |
expired = record.isExpired(now)
|
|
|
973 |
try:
|
|
|
974 |
oldrecord = self.services[record.alias.lower()]
|
|
|
975 |
if not expired:
|
|
|
976 |
oldrecord.resetTTL(record)
|
|
|
977 |
else:
|
|
|
978 |
del(self.services[record.alias.lower()])
|
|
|
979 |
callback = lambda x: self.listener.removeService(x, self.type, record.alias)
|
|
|
980 |
self.list.append(callback)
|
|
|
981 |
return
|
|
|
982 |
except:
|
|
|
983 |
if not expired:
|
|
|
984 |
self.services[record.alias.lower()] = record
|
|
|
985 |
callback = lambda x: self.listener.addService(x, self.type, record.alias)
|
|
|
986 |
self.list.append(callback)
|
|
|
987 |
|
|
|
988 |
expires = record.getExpirationTime(75)
|
|
|
989 |
if expires < self.nextTime:
|
|
|
990 |
self.nextTime = expires
|
|
|
991 |
|
|
|
992 |
def cancel(self):
|
|
|
993 |
self.done = 1
|
|
|
994 |
self.zeroconf.notifyAll()
|
|
|
995 |
|
|
|
996 |
def run(self):
|
|
|
997 |
while 1:
|
|
|
998 |
event = None
|
|
|
999 |
now = currentTimeMillis()
|
|
|
1000 |
if len(self.list) == 0 and self.nextTime > now:
|
|
|
1001 |
self.zeroconf.wait(self.nextTime - now)
|
|
|
1002 |
if globals()['_GLOBAL_DONE'] or self.done:
|
|
|
1003 |
return
|
|
|
1004 |
now = currentTimeMillis()
|
|
|
1005 |
|
|
|
1006 |
if self.nextTime <= now:
|
|
|
1007 |
out = DNSOutgoing(_FLAGS_QR_QUERY)
|
|
|
1008 |
out.addQuestion(DNSQuestion(self.type, _TYPE_PTR, _CLASS_IN))
|
|
|
1009 |
for record in self.services.values():
|
|
|
1010 |
if not record.isExpired(now):
|
|
|
1011 |
out.addAnswerAtTime(record, now)
|
|
|
1012 |
self.zeroconf.send(out)
|
|
|
1013 |
self.nextTime = now + self.delay
|
|
|
1014 |
self.delay = min(20 * 1000, self.delay * 2)
|
|
|
1015 |
|
|
|
1016 |
if len(self.list) > 0:
|
|
|
1017 |
event = self.list.pop(0)
|
|
|
1018 |
|
|
|
1019 |
if event is not None:
|
|
|
1020 |
event(self.zeroconf)
|
|
|
1021 |
|
|
|
1022 |
|
|
|
1023 |
class ServiceInfo(object):
|
|
|
1024 |
"""Service information"""
|
|
|
1025 |
|
|
|
1026 |
def __init__(self, type, name, address=None, port=None, weight=0, priority=0, properties=None, server=None):
|
|
|
1027 |
"""Create a service description.
|
|
|
1028 |
|
|
|
1029 |
type: fully qualified service type name
|
|
|
1030 |
name: fully qualified service name
|
|
|
1031 |
address: IP address as unsigned short, network byte order
|
|
|
1032 |
port: port that the service runs on
|
|
|
1033 |
weight: weight of the service
|
|
|
1034 |
priority: priority of the service
|
|
|
1035 |
properties: dictionary of properties (or a string holding the bytes for the text field)
|
|
|
1036 |
server: fully qualified name for service host (defaults to name)"""
|
|
|
1037 |
|
|
|
1038 |
if not name.endswith(type):
|
|
|
1039 |
raise BadTypeInNameException
|
|
|
1040 |
self.type = type
|
|
|
1041 |
self.name = name
|
|
|
1042 |
self.address = address
|
|
|
1043 |
self.port = port
|
|
|
1044 |
self.weight = weight
|
|
|
1045 |
self.priority = priority
|
|
|
1046 |
if server:
|
|
|
1047 |
self.server = server
|
|
|
1048 |
else:
|
|
|
1049 |
self.server = name
|
|
|
1050 |
self.setProperties(properties)
|
|
|
1051 |
|
|
|
1052 |
def setProperties(self, properties):
|
|
|
1053 |
"""Sets properties and text of this info from a dictionary"""
|
|
|
1054 |
if isinstance(properties, dict):
|
|
|
1055 |
self.properties = properties
|
|
|
1056 |
list = []
|
|
|
1057 |
result = ''
|
|
|
1058 |
for key in properties:
|
|
|
1059 |
value = properties[key]
|
|
|
1060 |
if value is None:
|
|
|
1061 |
suffix = ''.encode('utf-8')
|
|
|
1062 |
elif isinstance(value, str):
|
|
|
1063 |
suffix = value.encode('utf-8')
|
|
|
1064 |
elif isinstance(value, int):
|
|
|
1065 |
if value:
|
|
|
1066 |
suffix = 'true'
|
|
|
1067 |
else:
|
|
|
1068 |
suffix = 'false'
|
|
|
1069 |
else:
|
|
|
1070 |
suffix = ''.encode('utf-8')
|
|
|
1071 |
list.append('='.join((key, suffix)))
|
|
|
1072 |
for item in list:
|
|
|
1073 |
result = ''.join((result, struct.pack('!c', chr(len(item))), item))
|
|
|
1074 |
self.text = result
|
|
|
1075 |
else:
|
|
|
1076 |
self.text = properties
|
|
|
1077 |
|
|
|
1078 |
def setText(self, text):
|
|
|
1079 |
"""Sets properties and text given a text field"""
|
|
|
1080 |
self.text = text
|
|
|
1081 |
try:
|
|
|
1082 |
result = {}
|
|
|
1083 |
end = len(text)
|
|
|
1084 |
index = 0
|
|
|
1085 |
strs = []
|
|
|
1086 |
while index < end:
|
|
|
1087 |
length = ord(text[index])
|
|
|
1088 |
index += 1
|
|
|
1089 |
strs.append(text[index:index+length])
|
|
|
1090 |
index += length
|
|
|
1091 |
|
|
|
1092 |
for s in strs:
|
|
|
1093 |
eindex = s.find('=')
|
|
|
1094 |
if eindex == -1:
|
|
|
1095 |
# No equals sign at all
|
|
|
1096 |
key = s
|
|
|
1097 |
value = 0
|
|
|
1098 |
else:
|
|
|
1099 |
key = s[:eindex]
|
|
|
1100 |
value = s[eindex+1:]
|
|
|
1101 |
if value == 'true':
|
|
|
1102 |
value = 1
|
|
|
1103 |
elif value == 'false' or not value:
|
|
|
1104 |
value = 0
|
|
|
1105 |
|
|
|
1106 |
# Only update non-existent properties
|
|
|
1107 |
if key and result.get(key) == None:
|
|
|
1108 |
result[key] = value
|
|
|
1109 |
|
|
|
1110 |
self.properties = result
|
|
|
1111 |
except:
|
|
|
1112 |
traceback.print_exc()
|
|
|
1113 |
self.properties = None
|
|
|
1114 |
|
|
|
1115 |
def getType(self):
|
|
|
1116 |
"""Type accessor"""
|
|
|
1117 |
return self.type
|
|
|
1118 |
|
|
|
1119 |
def getName(self):
|
|
|
1120 |
"""Name accessor"""
|
|
|
1121 |
if self.type is not None and self.name.endswith("." + self.type):
|
|
|
1122 |
return self.name[:len(self.name) - len(self.type) - 1]
|
|
|
1123 |
return self.name
|
|
|
1124 |
|
|
|
1125 |
def getAddress(self):
|
|
|
1126 |
"""Address accessor"""
|
|
|
1127 |
return self.address
|
|
|
1128 |
|
|
|
1129 |
def getPort(self):
|
|
|
1130 |
"""Port accessor"""
|
|
|
1131 |
return self.port
|
|
|
1132 |
|
|
|
1133 |
def getPriority(self):
|
|
|
1134 |
"""Pirority accessor"""
|
|
|
1135 |
return self.priority
|
|
|
1136 |
|
|
|
1137 |
def getWeight(self):
|
|
|
1138 |
"""Weight accessor"""
|
|
|
1139 |
return self.weight
|
|
|
1140 |
|
|
|
1141 |
def getProperties(self):
|
|
|
1142 |
"""Properties accessor"""
|
|
|
1143 |
return self.properties
|
|
|
1144 |
|
|
|
1145 |
def getText(self):
|
|
|
1146 |
"""Text accessor"""
|
|
|
1147 |
return self.text
|
|
|
1148 |
|
|
|
1149 |
def getServer(self):
|
|
|
1150 |
"""Server accessor"""
|
|
|
1151 |
return self.server
|
|
|
1152 |
|
|
|
1153 |
def updateRecord(self, zeroconf, now, record):
|
|
|
1154 |
"""Updates service information from a DNS record"""
|
|
|
1155 |
if record is not None and not record.isExpired(now):
|
|
|
1156 |
if record.type == _TYPE_A:
|
|
|
1157 |
if record.name == self.name:
|
|
|
1158 |
self.address = record.address
|
|
|
1159 |
elif record.type == _TYPE_SRV:
|
|
|
1160 |
if record.name == self.name:
|
|
|
1161 |
self.server = record.server
|
|
|
1162 |
self.port = record.port
|
|
|
1163 |
self.weight = record.weight
|
|
|
1164 |
self.priority = record.priority
|
|
|
1165 |
self.address = None
|
|
|
1166 |
self.updateRecord(zeroconf, now, zeroconf.cache.getByDetails(self.server, _TYPE_A, _CLASS_IN))
|
|
|
1167 |
elif record.type == _TYPE_TXT:
|
|
|
1168 |
if record.name == self.name:
|
|
|
1169 |
self.setText(record.text)
|
|
|
1170 |
|
|
|
1171 |
def request(self, zeroconf, timeout):
|
|
|
1172 |
"""Returns true if the service could be discovered on the
|
|
|
1173 |
network, and updates this object with details discovered.
|
|
|
1174 |
"""
|
|
|
1175 |
now = currentTimeMillis()
|
|
|
1176 |
delay = _LISTENER_TIME
|
|
|
1177 |
next = now + delay
|
|
|
1178 |
last = now + timeout
|
|
|
1179 |
result = 0
|
|
|
1180 |
try:
|
|
|
1181 |
zeroconf.addListener(self, DNSQuestion(self.name, _TYPE_ANY, _CLASS_IN))
|
|
|
1182 |
while self.server is None or self.address is None or self.text is None:
|
|
|
1183 |
if last <= now:
|
|
|
1184 |
return 0
|
|
|
1185 |
if next <= now:
|
|
|
1186 |
out = DNSOutgoing(_FLAGS_QR_QUERY)
|
|
|
1187 |
out.addQuestion(DNSQuestion(self.name, _TYPE_SRV, _CLASS_IN))
|
|
|
1188 |
out.addAnswerAtTime(zeroconf.cache.getByDetails(self.name, _TYPE_SRV, _CLASS_IN), now)
|
|
|
1189 |
out.addQuestion(DNSQuestion(self.name, _TYPE_TXT, _CLASS_IN))
|
|
|
1190 |
out.addAnswerAtTime(zeroconf.cache.getByDetails(self.name, _TYPE_TXT, _CLASS_IN), now)
|
|
|
1191 |
if self.server is not None:
|
|
|
1192 |
out.addQuestion(DNSQuestion(self.server, _TYPE_A, _CLASS_IN))
|
|
|
1193 |
out.addAnswerAtTime(zeroconf.cache.getByDetails(self.server, _TYPE_A, _CLASS_IN), now)
|
|
|
1194 |
zeroconf.send(out)
|
|
|
1195 |
next = now + delay
|
|
|
1196 |
delay = delay * 2
|
|
|
1197 |
|
|
|
1198 |
zeroconf.wait(min(next, last) - now)
|
|
|
1199 |
now = currentTimeMillis()
|
|
|
1200 |
result = 1
|
|
|
1201 |
finally:
|
|
|
1202 |
zeroconf.removeListener(self)
|
|
|
1203 |
|
|
|
1204 |
return result
|
|
|
1205 |
|
|
|
1206 |
def __eq__(self, other):
|
|
|
1207 |
"""Tests equality of service name"""
|
|
|
1208 |
if isinstance(other, ServiceInfo):
|
|
|
1209 |
return other.name == self.name
|
|
|
1210 |
return 0
|
|
|
1211 |
|
|
|
1212 |
def __ne__(self, other):
|
|
|
1213 |
"""Non-equality test"""
|
|
|
1214 |
return not self.__eq__(other)
|
|
|
1215 |
|
|
|
1216 |
def __repr__(self):
|
|
|
1217 |
"""String representation"""
|
|
|
1218 |
result = "service[%s,%s:%s," % (self.name, socket.inet_ntoa(self.getAddress()), self.port)
|
|
|
1219 |
if self.text is None:
|
|
|
1220 |
result += "None"
|
|
|
1221 |
else:
|
|
|
1222 |
if len(self.text) < 20:
|
|
|
1223 |
result += self.text
|
|
|
1224 |
else:
|
|
|
1225 |
result += self.text[:17] + "..."
|
|
|
1226 |
result += "]"
|
|
|
1227 |
return result
|
|
|
1228 |
|
|
|
1229 |
|
|
|
1230 |
class Zeroconf(object):
|
|
|
1231 |
"""Implementation of Zeroconf Multicast DNS Service Discovery
|
|
|
1232 |
|
|
|
1233 |
Supports registration, unregistration, queries and browsing.
|
|
|
1234 |
"""
|
|
|
1235 |
def __init__(self, bindaddress=None):
|
|
|
1236 |
"""Creates an instance of the Zeroconf class, establishing
|
|
|
1237 |
multicast communications, listening and reaping threads."""
|
|
|
1238 |
globals()['_GLOBAL_DONE'] = 0
|
|
|
1239 |
if bindaddress is None:
|
|
|
1240 |
self.intf = socket.gethostbyname(socket.gethostname())
|
|
|
1241 |
else:
|
|
|
1242 |
self.intf = bindaddress
|
|
|
1243 |
self.group = ('', _MDNS_PORT)
|
|
|
1244 |
self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
|
|
|
1245 |
try:
|
|
|
1246 |
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
|
|
|
1247 |
self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
|
|
|
1248 |
except:
|
|
|
1249 |
# SO_REUSEADDR should be equivalent to SO_REUSEPORT for
|
|
|
1250 |
# multicast UDP sockets (p 731, "TCP/IP Illustrated,
|
|
|
1251 |
# Volume 2"), but some BSD-derived systems require
|
|
|
1252 |
# SO_REUSEPORT to be specified explicity. Also, not all
|
|
|
1253 |
# versions of Python have SO_REUSEPORT available. So
|
|
|
1254 |
# if you're on a BSD-based system, and haven't upgraded
|
|
|
1255 |
# to Python 2.3 yet, you may find this library doesn't
|
|
|
1256 |
# work as expected.
|
|
|
1257 |
#
|
|
|
1258 |
pass
|
|
|
1259 |
self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_TTL, 255)
|
|
|
1260 |
self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)
|
|
|
1261 |
try:
|
|
|
1262 |
self.socket.bind(self.group)
|
|
|
1263 |
except:
|
|
|
1264 |
# Some versions of linux raise an exception even though
|
|
|
1265 |
# the SO_REUSE* options have been set, so ignore it
|
|
|
1266 |
#
|
|
|
1267 |
pass
|
|
|
1268 |
self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(self.intf) + socket.inet_aton('0.0.0.0'))
|
|
|
1269 |
self.socket.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(_MDNS_ADDR) + socket.inet_aton('0.0.0.0'))
|
|
|
1270 |
|
|
|
1271 |
self.listeners = []
|
|
|
1272 |
self.browsers = []
|
|
|
1273 |
self.services = {}
|
|
|
1274 |
|
|
|
1275 |
self.cache = DNSCache()
|
|
|
1276 |
|
|
|
1277 |
self.condition = threading.Condition()
|
|
|
1278 |
|
|
|
1279 |
self.engine = Engine(self)
|
|
|
1280 |
self.listener = Listener(self)
|
|
|
1281 |
self.reaper = Reaper(self)
|
|
|
1282 |
|
|
|
1283 |
def isLoopback(self):
|
|
|
1284 |
return self.intf.startswith("127.0.0.1")
|
|
|
1285 |
|
|
|
1286 |
def isLinklocal(self):
|
|
|
1287 |
return self.intf.startswith("169.254.")
|
|
|
1288 |
|
|
|
1289 |
def wait(self, timeout):
|
|
|
1290 |
"""Calling thread waits for a given number of milliseconds or
|
|
|
1291 |
until notified."""
|
|
|
1292 |
self.condition.acquire()
|
|
|
1293 |
self.condition.wait(timeout/1000)
|
|
|
1294 |
self.condition.release()
|
|
|
1295 |
|
|
|
1296 |
def notifyAll(self):
|
|
|
1297 |
"""Notifies all waiting threads"""
|
|
|
1298 |
self.condition.acquire()
|
|
|
1299 |
self.condition.notifyAll()
|
|
|
1300 |
self.condition.release()
|
|
|
1301 |
|
|
|
1302 |
def getServiceInfo(self, type, name, timeout=3000):
|
|
|
1303 |
"""Returns network's service information for a particular
|
|
|
1304 |
name and type, or None if no service matches by the timeout,
|
|
|
1305 |
which defaults to 3 seconds."""
|
|
|
1306 |
info = ServiceInfo(type, name)
|
|
|
1307 |
if info.request(self, timeout):
|
|
|
1308 |
return info
|
|
|
1309 |
return None
|
|
|
1310 |
|
|
|
1311 |
def addServiceListener(self, type, listener):
|
|
|
1312 |
"""Adds a listener for a particular service type. This object
|
|
|
1313 |
will then have its updateRecord method called when information
|
|
|
1314 |
arrives for that type."""
|
|
|
1315 |
self.removeServiceListener(listener)
|
|
|
1316 |
self.browsers.append(ServiceBrowser(self, type, listener))
|
|
|
1317 |
|
|
|
1318 |
def removeServiceListener(self, listener):
|
|
|
1319 |
"""Removes a listener from the set that is currently listening."""
|
|
|
1320 |
for browser in self.browsers:
|
|
|
1321 |
if browser.listener == listener:
|
|
|
1322 |
browser.cancel()
|
|
|
1323 |
del(browser)
|
|
|
1324 |
|
|
|
1325 |
def registerService(self, info, ttl=_DNS_TTL):
|
|
|
1326 |
"""Registers service information to the network with a default TTL
|
|
|
1327 |
of 60 seconds. Zeroconf will then respond to requests for
|
|
|
1328 |
information for that service. The name of the service may be
|
|
|
1329 |
changed if needed to make it unique on the network."""
|
|
|
1330 |
self.checkService(info)
|
|
|
1331 |
self.services[info.name.lower()] = info
|
|
|
1332 |
now = currentTimeMillis()
|
|
|
1333 |
nextTime = now
|
|
|
1334 |
i = 0
|
|
|
1335 |
while i < 3:
|
|
|
1336 |
if now < nextTime:
|
|
|
1337 |
self.wait(nextTime - now)
|
|
|
1338 |
now = currentTimeMillis()
|
|
|
1339 |
continue
|
|
|
1340 |
out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
|
|
|
1341 |
out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, ttl, info.name), 0)
|
|
|
1342 |
out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, ttl, info.priority, info.weight, info.port, info.server), 0)
|
|
|
1343 |
out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, ttl, info.text), 0)
|
|
|
1344 |
if info.address:
|
|
|
1345 |
out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, ttl, info.address), 0)
|
|
|
1346 |
self.send(out)
|
|
|
1347 |
i += 1
|
|
|
1348 |
nextTime += _REGISTER_TIME
|
|
|
1349 |
|
|
|
1350 |
def unregisterService(self, info):
|
|
|
1351 |
"""Unregister a service."""
|
|
|
1352 |
try:
|
|
|
1353 |
del(self.services[info.name.lower()])
|
|
|
1354 |
except:
|
|
|
1355 |
pass
|
|
|
1356 |
now = currentTimeMillis()
|
|
|
1357 |
nextTime = now
|
|
|
1358 |
i = 0
|
|
|
1359 |
while i < 3:
|
|
|
1360 |
if now < nextTime:
|
|
|
1361 |
self.wait(nextTime - now)
|
|
|
1362 |
now = currentTimeMillis()
|
|
|
1363 |
continue
|
|
|
1364 |
out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
|
|
|
1365 |
out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, 0, info.name), 0)
|
|
|
1366 |
out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, 0, info.priority, info.weight, info.port, info.name), 0)
|
|
|
1367 |
out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, 0, info.text), 0)
|
|
|
1368 |
if info.address:
|
|
|
1369 |
out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, 0, info.address), 0)
|
|
|
1370 |
self.send(out)
|
|
|
1371 |
i += 1
|
|
|
1372 |
nextTime += _UNREGISTER_TIME
|
|
|
1373 |
|
|
|
1374 |
def unregisterAllServices(self):
|
|
|
1375 |
"""Unregister all registered services."""
|
|
|
1376 |
if len(self.services) > 0:
|
|
|
1377 |
now = currentTimeMillis()
|
|
|
1378 |
nextTime = now
|
|
|
1379 |
i = 0
|
|
|
1380 |
while i < 3:
|
|
|
1381 |
if now < nextTime:
|
|
|
1382 |
self.wait(nextTime - now)
|
|
|
1383 |
now = currentTimeMillis()
|
|
|
1384 |
continue
|
|
|
1385 |
out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
|
|
|
1386 |
for info in self.services.values():
|
|
|
1387 |
out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, 0, info.name), 0)
|
|
|
1388 |
out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, 0, info.priority, info.weight, info.port, info.server), 0)
|
|
|
1389 |
out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, 0, info.text), 0)
|
|
|
1390 |
if info.address:
|
|
|
1391 |
out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, 0, info.address), 0)
|
|
|
1392 |
self.send(out)
|
|
|
1393 |
i += 1
|
|
|
1394 |
nextTime += _UNREGISTER_TIME
|
|
|
1395 |
|
|
|
1396 |
def checkService(self, info):
|
|
|
1397 |
"""Checks the network for a unique service name, modifying the
|
|
|
1398 |
ServiceInfo passed in if it is not unique."""
|
|
|
1399 |
now = currentTimeMillis()
|
|
|
1400 |
nextTime = now
|
|
|
1401 |
i = 0
|
|
|
1402 |
while i < 3:
|
|
|
1403 |
for record in self.cache.entriesWithName(info.type):
|
|
|
1404 |
if record.type == _TYPE_PTR and not record.isExpired(now) and record.alias == info.name:
|
|
|
1405 |
if (info.name.find('.') < 0):
|
|
|
1406 |
info.name = info.name + ".[" + info.address + ":" + info.port + "]." + info.type
|
|
|
1407 |
self.checkService(info)
|
|
|
1408 |
return
|
|
|
1409 |
raise NonUniqueNameException
|
|
|
1410 |
if now < nextTime:
|
|
|
1411 |
self.wait(nextTime - now)
|
|
|
1412 |
now = currentTimeMillis()
|
|
|
1413 |
continue
|
|
|
1414 |
out = DNSOutgoing(_FLAGS_QR_QUERY | _FLAGS_AA)
|
|
|
1415 |
self.debug = out
|
|
|
1416 |
out.addQuestion(DNSQuestion(info.type, _TYPE_PTR, _CLASS_IN))
|
|
|
1417 |
out.addAuthorativeAnswer(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, _DNS_TTL, info.name))
|
|
|
1418 |
self.send(out)
|
|
|
1419 |
i += 1
|
|
|
1420 |
nextTime += _CHECK_TIME
|
|
|
1421 |
|
|
|
1422 |
def addListener(self, listener, question):
|
|
|
1423 |
"""Adds a listener for a given question. The listener will have
|
|
|
1424 |
its updateRecord method called when information is available to
|
|
|
1425 |
answer the question."""
|
|
|
1426 |
now = currentTimeMillis()
|
|
|
1427 |
self.listeners.append(listener)
|
|
|
1428 |
if question is not None:
|
|
|
1429 |
for record in self.cache.entriesWithName(question.name):
|
|
|
1430 |
if question.answeredBy(record) and not record.isExpired(now):
|
|
|
1431 |
listener.updateRecord(self, now, record)
|
|
|
1432 |
self.notifyAll()
|
|
|
1433 |
|
|
|
1434 |
def removeListener(self, listener):
|
|
|
1435 |
"""Removes a listener."""
|
|
|
1436 |
try:
|
|
|
1437 |
self.listeners.remove(listener)
|
|
|
1438 |
self.notifyAll()
|
|
|
1439 |
except:
|
|
|
1440 |
pass
|
|
|
1441 |
|
|
|
1442 |
def updateRecord(self, now, rec):
|
|
|
1443 |
"""Used to notify listeners of new information that has updated
|
|
|
1444 |
a record."""
|
|
|
1445 |
for listener in self.listeners:
|
|
|
1446 |
listener.updateRecord(self, now, rec)
|
|
|
1447 |
self.notifyAll()
|
|
|
1448 |
|
|
|
1449 |
def handleResponse(self, msg):
|
|
|
1450 |
"""Deal with incoming response packets. All answers
|
|
|
1451 |
are held in the cache, and listeners are notified."""
|
|
|
1452 |
now = currentTimeMillis()
|
|
|
1453 |
for record in msg.answers:
|
|
|
1454 |
expired = record.isExpired(now)
|
|
|
1455 |
if record in self.cache.entries():
|
|
|
1456 |
if expired:
|
|
|
1457 |
self.cache.remove(record)
|
|
|
1458 |
else:
|
|
|
1459 |
entry = self.cache.get(record)
|
|
|
1460 |
if entry is not None:
|
|
|
1461 |
entry.resetTTL(record)
|
|
|
1462 |
record = entry
|
|
|
1463 |
else:
|
|
|
1464 |
self.cache.add(record)
|
|
|
1465 |
|
|
|
1466 |
self.updateRecord(now, record)
|
|
|
1467 |
|
|
|
1468 |
def handleQuery(self, msg, addr, port):
|
|
|
1469 |
"""Deal with incoming query packets. Provides a response if
|
|
|
1470 |
possible."""
|
|
|
1471 |
out = None
|
|
|
1472 |
|
|
|
1473 |
# Support unicast client responses
|
|
|
1474 |
#
|
|
|
1475 |
if port != _MDNS_PORT:
|
|
|
1476 |
out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA, 0)
|
|
|
1477 |
for question in msg.questions:
|
|
|
1478 |
out.addQuestion(question)
|
|
|
1479 |
|
|
|
1480 |
for question in msg.questions:
|
|
|
1481 |
if question.type == _TYPE_PTR:
|
|
|
1482 |
for service in self.services.values():
|
|
|
1483 |
if question.name == service.type:
|
|
|
1484 |
if out is None:
|
|
|
1485 |
out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
|
|
|
1486 |
out.addAnswer(msg, DNSPointer(service.type, _TYPE_PTR, _CLASS_IN, _DNS_TTL, service.name))
|
|
|
1487 |
else:
|
|
|
1488 |
try:
|
|
|
1489 |
if out is None:
|
|
|
1490 |
out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
|
|
|
1491 |
|
|
|
1492 |
# Answer A record queries for any service addresses we know
|
|
|
1493 |
if question.type == _TYPE_A or question.type == _TYPE_ANY:
|
|
|
1494 |
for service in self.services.values():
|
|
|
1495 |
if service.server == question.name.lower():
|
|
|
1496 |
out.addAnswer(msg, DNSAddress(question.name, _TYPE_A, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.address))
|
|
|
1497 |
|
|
|
1498 |
service = self.services.get(question.name.lower(), None)
|
|
|
1499 |
if not service: continue
|
|
|
1500 |
|
|
|
1501 |
if question.type == _TYPE_SRV or question.type == _TYPE_ANY:
|
|
|
1502 |
out.addAnswer(msg, DNSService(question.name, _TYPE_SRV, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.priority, service.weight, service.port, service.server))
|
|
|
1503 |
if question.type == _TYPE_TXT or question.type == _TYPE_ANY:
|
|
|
1504 |
out.addAnswer(msg, DNSText(question.name, _TYPE_TXT, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.text))
|
|
|
1505 |
if question.type == _TYPE_SRV:
|
|
|
1506 |
out.addAdditionalAnswer(DNSAddress(service.server, _TYPE_A, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.address))
|
|
|
1507 |
except:
|
|
|
1508 |
traceback.print_exc()
|
|
|
1509 |
|
|
|
1510 |
if out is not None and out.answers:
|
|
|
1511 |
out.id = msg.id
|
|
|
1512 |
self.send(out, addr, port)
|
|
|
1513 |
|
|
|
1514 |
def send(self, out, addr = _MDNS_ADDR, port = _MDNS_PORT):
|
|
|
1515 |
"""Sends an outgoing packet."""
|
|
|
1516 |
# This is a quick test to see if we can parse the packets we generate
|
|
|
1517 |
#temp = DNSIncoming(out.packet())
|
|
|
1518 |
try:
|
|
|
1519 |
bytes_sent = self.socket.sendto(out.packet(), 0, (addr, port))
|
|
|
1520 |
except:
|
|
|
1521 |
# Ignore this, it may be a temporary loss of network connection
|
|
|
1522 |
pass
|
|
|
1523 |
|
|
|
1524 |
def close(self):
|
|
|
1525 |
"""Ends the background threads, and prevent this instance from
|
|
|
1526 |
servicing further queries."""
|
|
|
1527 |
if globals()['_GLOBAL_DONE'] == 0:
|
|
|
1528 |
globals()['_GLOBAL_DONE'] = 1
|
|
|
1529 |
self.notifyAll()
|
|
|
1530 |
self.engine.notify()
|
|
|
1531 |
self.unregisterAllServices()
|
|
|
1532 |
self.socket.setsockopt(socket.SOL_IP, socket.IP_DROP_MEMBERSHIP, socket.inet_aton(_MDNS_ADDR) + socket.inet_aton('0.0.0.0'))
|
|
|
1533 |
self.socket.close()
|
|
|
1534 |
|
|
|
1535 |
# Test a few module features, including service registration, service
|
|
|
1536 |
# query (for Zoe), and service unregistration.
|
|
|
1537 |
|
|
|
1538 |
if __name__ == '__main__':
|
|
|
1539 |
print "Multicast DNS Service Discovery for Python, version", __version__
|
|
|
1540 |
r = Zeroconf()
|
|
|
1541 |
print "1. Testing registration of a service..."
|
|
|
1542 |
desc = {'version':'0.10','a':'test value', 'b':'another value'}
|
|
|
1543 |
info = ServiceInfo("_http._tcp.local.", "My Service Name._http._tcp.local.", socket.inet_aton("127.0.0.1"), 1234, 0, 0, desc)
|
|
|
1544 |
print " Registering service..."
|
|
|
1545 |
r.registerService(info)
|
|
|
1546 |
print " Registration done."
|
|
|
1547 |
print "2. Testing query of service information..."
|
|
|
1548 |
print " Getting ZOE service:", str(r.getServiceInfo("_http._tcp.local.", "ZOE._http._tcp.local."))
|
|
|
1549 |
print " Query done."
|
|
|
1550 |
print "3. Testing query of own service..."
|
|
|
1551 |
print " Getting self:", str(r.getServiceInfo("_http._tcp.local.", "My Service Name._http._tcp.local."))
|
|
|
1552 |
print " Query done."
|
|
|
1553 |
print "4. Testing unregister of service information..."
|
|
|
1554 |
r.unregisterService(info)
|
|
|
1555 |
print " Unregister done."
|
|
|
1556 |
r.close()
|