--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Zeroconf.py Wed Aug 20 00:11:40 2008 +0200
@@ -0,0 +1,1556 @@
+""" Multicast DNS Service Discovery for Python, v0.12
+ Copyright (C) 2003, Paul Scott-Murphy
+
+ This module provides a framework for the use of DNS Service Discovery
+ using IP multicast. It has been tested against the JRendezvous
+ implementation from <a href="http://strangeberry.com">StrangeBerry</a>,
+ and against the mDNSResponder from Mac OS X 10.3.8.
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+"""
+
+"""0.12 update - allow selection of binding interface
+ typo fix - Thanks A. M. Kuchlingi
+ removed all use of word 'Rendezvous' - this is an API change"""
+
+"""0.11 update - correction to comments for addListener method
+ support for new record types seen from OS X
+ - IPv6 address
+ - hostinfo
+ ignore unknown DNS record types
+ fixes to name decoding
+ works alongside other processes using port 5353 (e.g. on Mac OS X)
+ tested against Mac OS X 10.3.2's mDNSResponder
+ corrections to removal of list entries for service browser"""
+
+"""0.10 update - Jonathon Paisley contributed these corrections:
+ always multicast replies, even when query is unicast
+ correct a pointer encoding problem
+ can now write records in any order
+ traceback shown on failure
+ better TXT record parsing
+ server is now separate from name
+ can cancel a service browser
+
+ modified some unit tests to accommodate these changes"""
+
+"""0.09 update - remove all records on service unregistration
+ fix DOS security problem with readName"""
+
+"""0.08 update - changed licensing to LGPL"""
+
+"""0.07 update - faster shutdown on engine
+ pointer encoding of outgoing names
+ ServiceBrowser now works
+ new unit tests"""
+
+"""0.06 update - small improvements with unit tests
+ added defined exception types
+ new style objects
+ fixed hostname/interface problem
+ fixed socket timeout problem
+ fixed addServiceListener() typo bug
+ using select() for socket reads
+ tested on Debian unstable with Python 2.2.2"""
+
+"""0.05 update - ensure case insensitivty on domain names
+ support for unicast DNS queries"""
+
+"""0.04 update - added some unit tests
+ added __ne__ adjuncts where required
+ ensure names end in '.local.'
+ timeout on receiving socket for clean shutdown"""
+
+__author__ = "Paul Scott-Murphy"
+__email__ = "paul at scott dash murphy dot com"
+__version__ = "0.12"
+
+import string
+import time
+import struct
+import socket
+import threading
+import select
+import traceback
+
+__all__ = ["Zeroconf", "ServiceInfo", "ServiceBrowser"]
+
+# hook for threads
+
+globals()['_GLOBAL_DONE'] = 0
+
+# Some timing constants
+
+_UNREGISTER_TIME = 125
+_CHECK_TIME = 175
+_REGISTER_TIME = 225
+_LISTENER_TIME = 200
+_BROWSER_TIME = 500
+
+# Some DNS constants
+
+_MDNS_ADDR = '224.0.0.251'
+_MDNS_PORT = 5353;
+_DNS_PORT = 53;
+_DNS_TTL = 60 * 60; # one hour default TTL
+
+_MAX_MSG_TYPICAL = 1460 # unused
+_MAX_MSG_ABSOLUTE = 8972
+
+_FLAGS_QR_MASK = 0x8000 # query response mask
+_FLAGS_QR_QUERY = 0x0000 # query
+_FLAGS_QR_RESPONSE = 0x8000 # response
+
+_FLAGS_AA = 0x0400 # Authorative answer
+_FLAGS_TC = 0x0200 # Truncated
+_FLAGS_RD = 0x0100 # Recursion desired
+_FLAGS_RA = 0x8000 # Recursion available
+
+_FLAGS_Z = 0x0040 # Zero
+_FLAGS_AD = 0x0020 # Authentic data
+_FLAGS_CD = 0x0010 # Checking disabled
+
+_CLASS_IN = 1
+_CLASS_CS = 2
+_CLASS_CH = 3
+_CLASS_HS = 4
+_CLASS_NONE = 254
+_CLASS_ANY = 255
+_CLASS_MASK = 0x7FFF
+_CLASS_UNIQUE = 0x8000
+
+_TYPE_A = 1
+_TYPE_NS = 2
+_TYPE_MD = 3
+_TYPE_MF = 4
+_TYPE_CNAME = 5
+_TYPE_SOA = 6
+_TYPE_MB = 7
+_TYPE_MG = 8
+_TYPE_MR = 9
+_TYPE_NULL = 10
+_TYPE_WKS = 11
+_TYPE_PTR = 12
+_TYPE_HINFO = 13
+_TYPE_MINFO = 14
+_TYPE_MX = 15
+_TYPE_TXT = 16
+_TYPE_AAAA = 28
+_TYPE_SRV = 33
+_TYPE_ANY = 255
+
+# Mapping constants to names
+
+_CLASSES = { _CLASS_IN : "in",
+ _CLASS_CS : "cs",
+ _CLASS_CH : "ch",
+ _CLASS_HS : "hs",
+ _CLASS_NONE : "none",
+ _CLASS_ANY : "any" }
+
+_TYPES = { _TYPE_A : "a",
+ _TYPE_NS : "ns",
+ _TYPE_MD : "md",
+ _TYPE_MF : "mf",
+ _TYPE_CNAME : "cname",
+ _TYPE_SOA : "soa",
+ _TYPE_MB : "mb",
+ _TYPE_MG : "mg",
+ _TYPE_MR : "mr",
+ _TYPE_NULL : "null",
+ _TYPE_WKS : "wks",
+ _TYPE_PTR : "ptr",
+ _TYPE_HINFO : "hinfo",
+ _TYPE_MINFO : "minfo",
+ _TYPE_MX : "mx",
+ _TYPE_TXT : "txt",
+ _TYPE_AAAA : "quada",
+ _TYPE_SRV : "srv",
+ _TYPE_ANY : "any" }
+
+# utility functions
+
+def currentTimeMillis():
+ """Current system time in milliseconds"""
+ return time.time() * 1000
+
+# Exceptions
+
+class NonLocalNameException(Exception):
+ pass
+
+class NonUniqueNameException(Exception):
+ pass
+
+class NamePartTooLongException(Exception):
+ pass
+
+class AbstractMethodException(Exception):
+ pass
+
+class BadTypeInNameException(Exception):
+ pass
+
+# implementation classes
+
+class DNSEntry(object):
+ """A DNS entry"""
+
+ def __init__(self, name, type, clazz):
+ self.key = string.lower(name)
+ self.name = name
+ self.type = type
+ self.clazz = clazz & _CLASS_MASK
+ self.unique = (clazz & _CLASS_UNIQUE) != 0
+
+ def __eq__(self, other):
+ """Equality test on name, type, and class"""
+ if isinstance(other, DNSEntry):
+ return self.name == other.name and self.type == other.type and self.clazz == other.clazz
+ return 0
+
+ def __ne__(self, other):
+ """Non-equality test"""
+ return not self.__eq__(other)
+
+ def getClazz(self, clazz):
+ """Class accessor"""
+ try:
+ return _CLASSES[clazz]
+ except:
+ return "?(%s)" % (clazz)
+
+ def getType(self, type):
+ """Type accessor"""
+ try:
+ return _TYPES[type]
+ except:
+ return "?(%s)" % (type)
+
+ def toString(self, hdr, other):
+ """String representation with additional information"""
+ result = "%s[%s,%s" % (hdr, self.getType(self.type), self.getClazz(self.clazz))
+ if self.unique:
+ result += "-unique,"
+ else:
+ result += ","
+ result += self.name
+ if other is not None:
+ result += ",%s]" % (other)
+ else:
+ result += "]"
+ return result
+
+class DNSQuestion(DNSEntry):
+ """A DNS question entry"""
+
+ def __init__(self, name, type, clazz):
+ if not name.endswith(".local."):
+ raise NonLocalNameException
+ DNSEntry.__init__(self, name, type, clazz)
+
+ def answeredBy(self, rec):
+ """Returns true if the question is answered by the record"""
+ return self.clazz == rec.clazz and (self.type == rec.type or self.type == _TYPE_ANY) and self.name == rec.name
+
+ def __repr__(self):
+ """String representation"""
+ return DNSEntry.toString(self, "question", None)
+
+
+class DNSRecord(DNSEntry):
+ """A DNS record - like a DNS entry, but has a TTL"""
+
+ def __init__(self, name, type, clazz, ttl):
+ DNSEntry.__init__(self, name, type, clazz)
+ self.ttl = ttl
+ self.created = currentTimeMillis()
+
+ def __eq__(self, other):
+ """Tests equality as per DNSRecord"""
+ if isinstance(other, DNSRecord):
+ return DNSEntry.__eq__(self, other)
+ return 0
+
+ def suppressedBy(self, msg):
+ """Returns true if any answer in a message can suffice for the
+ information held in this record."""
+ for record in msg.answers:
+ if self.suppressedByAnswer(record):
+ return 1
+ return 0
+
+ def suppressedByAnswer(self, other):
+ """Returns true if another record has same name, type and class,
+ and if its TTL is at least half of this record's."""
+ if self == other and other.ttl > (self.ttl / 2):
+ return 1
+ return 0
+
+ def getExpirationTime(self, percent):
+ """Returns the time at which this record will have expired
+ by a certain percentage."""
+ return self.created + (percent * self.ttl * 10)
+
+ def getRemainingTTL(self, now):
+ """Returns the remaining TTL in seconds."""
+ return max(0, (self.getExpirationTime(100) - now) / 1000)
+
+ def isExpired(self, now):
+ """Returns true if this record has expired."""
+ return self.getExpirationTime(100) <= now
+
+ def isStale(self, now):
+ """Returns true if this record is at least half way expired."""
+ return self.getExpirationTime(50) <= now
+
+ def resetTTL(self, other):
+ """Sets this record's TTL and created time to that of
+ another record."""
+ self.created = other.created
+ self.ttl = other.ttl
+
+ def write(self, out):
+ """Abstract method"""
+ raise AbstractMethodException
+
+ def toString(self, other):
+ """String representation with addtional information"""
+ arg = "%s/%s,%s" % (self.ttl, self.getRemainingTTL(currentTimeMillis()), other)
+ return DNSEntry.toString(self, "record", arg)
+
+class DNSAddress(DNSRecord):
+ """A DNS address record"""
+
+ def __init__(self, name, type, clazz, ttl, address):
+ DNSRecord.__init__(self, name, type, clazz, ttl)
+ self.address = address
+
+ def write(self, out):
+ """Used in constructing an outgoing packet"""
+ out.writeString(self.address, len(self.address))
+
+ def __eq__(self, other):
+ """Tests equality on address"""
+ if isinstance(other, DNSAddress):
+ return self.address == other.address
+ return 0
+
+ def __repr__(self):
+ """String representation"""
+ try:
+ return socket.inet_ntoa(self.address)
+ except:
+ return self.address
+
+class DNSHinfo(DNSRecord):
+ """A DNS host information record"""
+
+ def __init__(self, name, type, clazz, ttl, cpu, os):
+ DNSRecord.__init__(self, name, type, clazz, ttl)
+ self.cpu = cpu
+ self.os = os
+
+ def write(self, out):
+ """Used in constructing an outgoing packet"""
+ out.writeString(self.cpu, len(self.cpu))
+ out.writeString(self.os, len(self.os))
+
+ def __eq__(self, other):
+ """Tests equality on cpu and os"""
+ if isinstance(other, DNSHinfo):
+ return self.cpu == other.cpu and self.os == other.os
+ return 0
+
+ def __repr__(self):
+ """String representation"""
+ return self.cpu + " " + self.os
+
+class DNSPointer(DNSRecord):
+ """A DNS pointer record"""
+
+ def __init__(self, name, type, clazz, ttl, alias):
+ DNSRecord.__init__(self, name, type, clazz, ttl)
+ self.alias = alias
+
+ def write(self, out):
+ """Used in constructing an outgoing packet"""
+ out.writeName(self.alias)
+
+ def __eq__(self, other):
+ """Tests equality on alias"""
+ if isinstance(other, DNSPointer):
+ return self.alias == other.alias
+ return 0
+
+ def __repr__(self):
+ """String representation"""
+ return self.toString(self.alias)
+
+class DNSText(DNSRecord):
+ """A DNS text record"""
+
+ def __init__(self, name, type, clazz, ttl, text):
+ DNSRecord.__init__(self, name, type, clazz, ttl)
+ self.text = text
+
+ def write(self, out):
+ """Used in constructing an outgoing packet"""
+ out.writeString(self.text, len(self.text))
+
+ def __eq__(self, other):
+ """Tests equality on text"""
+ if isinstance(other, DNSText):
+ return self.text == other.text
+ return 0
+
+ def __repr__(self):
+ """String representation"""
+ if len(self.text) > 10:
+ return self.toString(self.text[:7] + "...")
+ else:
+ return self.toString(self.text)
+
+class DNSService(DNSRecord):
+ """A DNS service record"""
+
+ def __init__(self, name, type, clazz, ttl, priority, weight, port, server):
+ DNSRecord.__init__(self, name, type, clazz, ttl)
+ self.priority = priority
+ self.weight = weight
+ self.port = port
+ self.server = server
+
+ def write(self, out):
+ """Used in constructing an outgoing packet"""
+ out.writeShort(self.priority)
+ out.writeShort(self.weight)
+ out.writeShort(self.port)
+ out.writeName(self.server)
+
+ def __eq__(self, other):
+ """Tests equality on priority, weight, port and server"""
+ if isinstance(other, DNSService):
+ return self.priority == other.priority and self.weight == other.weight and self.port == other.port and self.server == other.server
+ return 0
+
+ def __repr__(self):
+ """String representation"""
+ return self.toString("%s:%s" % (self.server, self.port))
+
+class DNSIncoming(object):
+ """Object representation of an incoming DNS packet"""
+
+ def __init__(self, data):
+ """Constructor from string holding bytes of packet"""
+ self.offset = 0
+ self.data = data
+ self.questions = []
+ self.answers = []
+ self.numQuestions = 0
+ self.numAnswers = 0
+ self.numAuthorities = 0
+ self.numAdditionals = 0
+
+ self.readHeader()
+ self.readQuestions()
+ self.readOthers()
+
+ def readHeader(self):
+ """Reads header portion of packet"""
+ format = '!HHHHHH'
+ length = struct.calcsize(format)
+ info = struct.unpack(format, self.data[self.offset:self.offset+length])
+ self.offset += length
+
+ self.id = info[0]
+ self.flags = info[1]
+ self.numQuestions = info[2]
+ self.numAnswers = info[3]
+ self.numAuthorities = info[4]
+ self.numAdditionals = info[5]
+
+ def readQuestions(self):
+ """Reads questions section of packet"""
+ format = '!HH'
+ length = struct.calcsize(format)
+ for i in range(0, self.numQuestions):
+ name = self.readName()
+ info = struct.unpack(format, self.data[self.offset:self.offset+length])
+ self.offset += length
+
+ question = DNSQuestion(name, info[0], info[1])
+ self.questions.append(question)
+
+ def readInt(self):
+ """Reads an integer from the packet"""
+ format = '!I'
+ length = struct.calcsize(format)
+ info = struct.unpack(format, self.data[self.offset:self.offset+length])
+ self.offset += length
+ return info[0]
+
+ def readCharacterString(self):
+ """Reads a character string from the packet"""
+ length = ord(self.data[self.offset])
+ self.offset += 1
+ return self.readString(length)
+
+ def readString(self, len):
+ """Reads a string of a given length from the packet"""
+ format = '!' + str(len) + 's'
+ length = struct.calcsize(format)
+ info = struct.unpack(format, self.data[self.offset:self.offset+length])
+ self.offset += length
+ return info[0]
+
+ def readUnsignedShort(self):
+ """Reads an unsigned short from the packet"""
+ format = '!H'
+ length = struct.calcsize(format)
+ info = struct.unpack(format, self.data[self.offset:self.offset+length])
+ self.offset += length
+ return info[0]
+
+ def readOthers(self):
+ """Reads the answers, authorities and additionals section of the packet"""
+ format = '!HHiH'
+ length = struct.calcsize(format)
+ n = self.numAnswers + self.numAuthorities + self.numAdditionals
+ for i in range(0, n):
+ domain = self.readName()
+ info = struct.unpack(format, self.data[self.offset:self.offset+length])
+ self.offset += length
+
+ rec = None
+ if info[0] == _TYPE_A:
+ rec = DNSAddress(domain, info[0], info[1], info[2], self.readString(4))
+ elif info[0] == _TYPE_CNAME or info[0] == _TYPE_PTR:
+ rec = DNSPointer(domain, info[0], info[1], info[2], self.readName())
+ elif info[0] == _TYPE_TXT:
+ rec = DNSText(domain, info[0], info[1], info[2], self.readString(info[3]))
+ elif info[0] == _TYPE_SRV:
+ rec = DNSService(domain, info[0], info[1], info[2], self.readUnsignedShort(), self.readUnsignedShort(), self.readUnsignedShort(), self.readName())
+ elif info[0] == _TYPE_HINFO:
+ rec = DNSHinfo(domain, info[0], info[1], info[2], self.readCharacterString(), self.readCharacterString())
+ elif info[0] == _TYPE_AAAA:
+ rec = DNSAddress(domain, info[0], info[1], info[2], self.readString(16))
+ else:
+ # Try to ignore types we don't know about
+ # this may mean the rest of the name is
+ # unable to be parsed, and may show errors
+ # so this is left for debugging. New types
+ # encountered need to be parsed properly.
+ #
+ #print "UNKNOWN TYPE = " + str(info[0])
+ #raise BadTypeInNameException
+ pass
+
+ if rec is not None:
+ self.answers.append(rec)
+
+ def isQuery(self):
+ """Returns true if this is a query"""
+ return (self.flags & _FLAGS_QR_MASK) == _FLAGS_QR_QUERY
+
+ def isResponse(self):
+ """Returns true if this is a response"""
+ return (self.flags & _FLAGS_QR_MASK) == _FLAGS_QR_RESPONSE
+
+ def readUTF(self, offset, len):
+ """Reads a UTF-8 string of a given length from the packet"""
+ result = self.data[offset:offset+len].decode('utf-8')
+ return result
+
+ def readName(self):
+ """Reads a domain name from the packet"""
+ result = ''
+ off = self.offset
+ next = -1
+ first = off
+
+ while 1:
+ len = ord(self.data[off])
+ off += 1
+ if len == 0:
+ break
+ t = len & 0xC0
+ if t == 0x00:
+ result = ''.join((result, self.readUTF(off, len) + '.'))
+ off += len
+ elif t == 0xC0:
+ if next < 0:
+ next = off + 1
+ off = ((len & 0x3F) << 8) | ord(self.data[off])
+ if off >= first:
+ raise "Bad domain name (circular) at " + str(off)
+ first = off
+ else:
+ raise "Bad domain name at " + str(off)
+
+ if next >= 0:
+ self.offset = next
+ else:
+ self.offset = off
+
+ return result
+
+
+class DNSOutgoing(object):
+ """Object representation of an outgoing packet"""
+
+ def __init__(self, flags, multicast = 1):
+ self.finished = 0
+ self.id = 0
+ self.multicast = multicast
+ self.flags = flags
+ self.names = {}
+ self.data = []
+ self.size = 12
+
+ self.questions = []
+ self.answers = []
+ self.authorities = []
+ self.additionals = []
+
+ def addQuestion(self, record):
+ """Adds a question"""
+ self.questions.append(record)
+
+ def addAnswer(self, inp, record):
+ """Adds an answer"""
+ if not record.suppressedBy(inp):
+ self.addAnswerAtTime(record, 0)
+
+ def addAnswerAtTime(self, record, now):
+ """Adds an answer if if does not expire by a certain time"""
+ if record is not None:
+ if now == 0 or not record.isExpired(now):
+ self.answers.append((record, now))
+
+ def addAuthorativeAnswer(self, record):
+ """Adds an authoritative answer"""
+ self.authorities.append(record)
+
+ def addAdditionalAnswer(self, record):
+ """Adds an additional answer"""
+ self.additionals.append(record)
+
+ def writeByte(self, value):
+ """Writes a single byte to the packet"""
+ format = '!c'
+ self.data.append(struct.pack(format, chr(value)))
+ self.size += 1
+
+ def insertShort(self, index, value):
+ """Inserts an unsigned short in a certain position in the packet"""
+ format = '!H'
+ self.data.insert(index, struct.pack(format, value))
+ self.size += 2
+
+ def writeShort(self, value):
+ """Writes an unsigned short to the packet"""
+ format = '!H'
+ self.data.append(struct.pack(format, value))
+ self.size += 2
+
+ def writeInt(self, value):
+ """Writes an unsigned integer to the packet"""
+ format = '!I'
+ self.data.append(struct.pack(format, int(value)))
+ self.size += 4
+
+ def writeString(self, value, length):
+ """Writes a string to the packet"""
+ format = '!' + str(length) + 's'
+ self.data.append(struct.pack(format, value))
+ self.size += length
+
+ def writeUTF(self, s):
+ """Writes a UTF-8 string of a given length to the packet"""
+ utfstr = s.encode('utf-8')
+ length = len(utfstr)
+ if length > 64:
+ raise NamePartTooLongException
+ self.writeByte(length)
+ self.writeString(utfstr, length)
+
+ def writeName(self, name):
+ """Writes a domain name to the packet"""
+
+ try:
+ # Find existing instance of this name in packet
+ #
+ index = self.names[name]
+ except KeyError:
+ # No record of this name already, so write it
+ # out as normal, recording the location of the name
+ # for future pointers to it.
+ #
+ self.names[name] = self.size
+ parts = name.split('.')
+ if parts[-1] == '':
+ parts = parts[:-1]
+ for part in parts:
+ self.writeUTF(part)
+ self.writeByte(0)
+ return
+
+ # An index was found, so write a pointer to it
+ #
+ self.writeByte((index >> 8) | 0xC0)
+ self.writeByte(index)
+
+ def writeQuestion(self, question):
+ """Writes a question to the packet"""
+ self.writeName(question.name)
+ self.writeShort(question.type)
+ self.writeShort(question.clazz)
+
+ def writeRecord(self, record, now):
+ """Writes a record (answer, authoritative answer, additional) to
+ the packet"""
+ self.writeName(record.name)
+ self.writeShort(record.type)
+ if record.unique and self.multicast:
+ self.writeShort(record.clazz | _CLASS_UNIQUE)
+ else:
+ self.writeShort(record.clazz)
+ if now == 0:
+ self.writeInt(record.ttl)
+ else:
+ self.writeInt(record.getRemainingTTL(now))
+ index = len(self.data)
+ # Adjust size for the short we will write before this record
+ #
+ self.size += 2
+ record.write(self)
+ self.size -= 2
+
+ length = len(''.join(self.data[index:]))
+ self.insertShort(index, length) # Here is the short we adjusted for
+
+ def packet(self):
+ """Returns a string containing the packet's bytes
+
+ No further parts should be added to the packet once this
+ is done."""
+ if not self.finished:
+ self.finished = 1
+ for question in self.questions:
+ self.writeQuestion(question)
+ for answer, time in self.answers:
+ self.writeRecord(answer, time)
+ for authority in self.authorities:
+ self.writeRecord(authority, 0)
+ for additional in self.additionals:
+ self.writeRecord(additional, 0)
+
+ self.insertShort(0, len(self.additionals))
+ self.insertShort(0, len(self.authorities))
+ self.insertShort(0, len(self.answers))
+ self.insertShort(0, len(self.questions))
+ self.insertShort(0, self.flags)
+ if self.multicast:
+ self.insertShort(0, 0)
+ else:
+ self.insertShort(0, self.id)
+ return ''.join(self.data)
+
+
+class DNSCache(object):
+ """A cache of DNS entries"""
+
+ def __init__(self):
+ self.cache = {}
+
+ def add(self, entry):
+ """Adds an entry"""
+ try:
+ list = self.cache[entry.key]
+ except:
+ list = self.cache[entry.key] = []
+ list.append(entry)
+
+ def remove(self, entry):
+ """Removes an entry"""
+ try:
+ list = self.cache[entry.key]
+ list.remove(entry)
+ except:
+ pass
+
+ def get(self, entry):
+ """Gets an entry by key. Will return None if there is no
+ matching entry."""
+ try:
+ list = self.cache[entry.key]
+ return list[list.index(entry)]
+ except:
+ return None
+
+ def getByDetails(self, name, type, clazz):
+ """Gets an entry by details. Will return None if there is
+ no matching entry."""
+ entry = DNSEntry(name, type, clazz)
+ return self.get(entry)
+
+ def entriesWithName(self, name):
+ """Returns a list of entries whose key matches the name."""
+ try:
+ return self.cache[name]
+ except:
+ return []
+
+ def entries(self):
+ """Returns a list of all entries"""
+ def add(x, y): return x+y
+ try:
+ return reduce(add, self.cache.values())
+ except:
+ return []
+
+
+class Engine(threading.Thread):
+ """An engine wraps read access to sockets, allowing objects that
+ need to receive data from sockets to be called back when the
+ sockets are ready.
+
+ A reader needs a handle_read() method, which is called when the socket
+ it is interested in is ready for reading.
+
+ Writers are not implemented here, because we only send short
+ packets.
+ """
+
+ def __init__(self, zeroconf):
+ threading.Thread.__init__(self)
+ self.zeroconf = zeroconf
+ self.readers = {} # maps socket to reader
+ self.timeout = 5
+ self.condition = threading.Condition()
+ self.start()
+
+ def run(self):
+ while not globals()['_GLOBAL_DONE']:
+ rs = self.getReaders()
+ if len(rs) == 0:
+ # No sockets to manage, but we wait for the timeout
+ # or addition of a socket
+ #
+ self.condition.acquire()
+ self.condition.wait(self.timeout)
+ self.condition.release()
+ else:
+ try:
+ rr, wr, er = select.select(rs, [], [], self.timeout)
+ for socket in rr:
+ try:
+ self.readers[socket].handle_read()
+ except:
+ traceback.print_exc()
+ except:
+ pass
+
+ def getReaders(self):
+ result = []
+ self.condition.acquire()
+ result = self.readers.keys()
+ self.condition.release()
+ return result
+
+ def addReader(self, reader, socket):
+ self.condition.acquire()
+ self.readers[socket] = reader
+ self.condition.notify()
+ self.condition.release()
+
+ def delReader(self, socket):
+ self.condition.acquire()
+ del(self.readers[socket])
+ self.condition.notify()
+ self.condition.release()
+
+ def notify(self):
+ self.condition.acquire()
+ self.condition.notify()
+ self.condition.release()
+
+class Listener(object):
+ """A Listener is used by this module to listen on the multicast
+ group to which DNS messages are sent, allowing the implementation
+ to cache information as it arrives.
+
+ It requires registration with an Engine object in order to have
+ the read() method called when a socket is availble for reading."""
+
+ def __init__(self, zeroconf):
+ self.zeroconf = zeroconf
+ self.zeroconf.engine.addReader(self, self.zeroconf.socket)
+
+ def handle_read(self):
+ data, (addr, port) = self.zeroconf.socket.recvfrom(_MAX_MSG_ABSOLUTE)
+ self.data = data
+ msg = DNSIncoming(data)
+ if msg.isQuery():
+ # Always multicast responses
+ #
+ if port == _MDNS_PORT:
+ self.zeroconf.handleQuery(msg, _MDNS_ADDR, _MDNS_PORT)
+ # If it's not a multicast query, reply via unicast
+ # and multicast
+ #
+ elif port == _DNS_PORT:
+ self.zeroconf.handleQuery(msg, addr, port)
+ self.zeroconf.handleQuery(msg, _MDNS_ADDR, _MDNS_PORT)
+ else:
+ self.zeroconf.handleResponse(msg)
+
+
+class Reaper(threading.Thread):
+ """A Reaper is used by this module to remove cache entries that
+ have expired."""
+
+ def __init__(self, zeroconf):
+ threading.Thread.__init__(self)
+ self.zeroconf = zeroconf
+ self.start()
+
+ def run(self):
+ while 1:
+ self.zeroconf.wait(10 * 1000)
+ if globals()['_GLOBAL_DONE']:
+ return
+ now = currentTimeMillis()
+ for record in self.zeroconf.cache.entries():
+ if record.isExpired(now):
+ self.zeroconf.updateRecord(now, record)
+ self.zeroconf.cache.remove(record)
+
+
+class ServiceBrowser(threading.Thread):
+ """Used to browse for a service of a specific type.
+
+ The listener object will have its addService() and
+ removeService() methods called when this browser
+ discovers changes in the services availability."""
+
+ def __init__(self, zeroconf, type, listener):
+ """Creates a browser for a specific type"""
+ threading.Thread.__init__(self)
+ self.zeroconf = zeroconf
+ self.type = type
+ self.listener = listener
+ self.services = {}
+ self.nextTime = currentTimeMillis()
+ self.delay = _BROWSER_TIME
+ self.list = []
+
+ self.done = 0
+
+ self.zeroconf.addListener(self, DNSQuestion(self.type, _TYPE_PTR, _CLASS_IN))
+ self.start()
+
+ def updateRecord(self, zeroconf, now, record):
+ """Callback invoked by Zeroconf when new information arrives.
+
+ Updates information required by browser in the Zeroconf cache."""
+ if record.type == _TYPE_PTR and record.name == self.type:
+ expired = record.isExpired(now)
+ try:
+ oldrecord = self.services[record.alias.lower()]
+ if not expired:
+ oldrecord.resetTTL(record)
+ else:
+ del(self.services[record.alias.lower()])
+ callback = lambda x: self.listener.removeService(x, self.type, record.alias)
+ self.list.append(callback)
+ return
+ except:
+ if not expired:
+ self.services[record.alias.lower()] = record
+ callback = lambda x: self.listener.addService(x, self.type, record.alias)
+ self.list.append(callback)
+
+ expires = record.getExpirationTime(75)
+ if expires < self.nextTime:
+ self.nextTime = expires
+
+ def cancel(self):
+ self.done = 1
+ self.zeroconf.notifyAll()
+
+ def run(self):
+ while 1:
+ event = None
+ now = currentTimeMillis()
+ if len(self.list) == 0 and self.nextTime > now:
+ self.zeroconf.wait(self.nextTime - now)
+ if globals()['_GLOBAL_DONE'] or self.done:
+ return
+ now = currentTimeMillis()
+
+ if self.nextTime <= now:
+ out = DNSOutgoing(_FLAGS_QR_QUERY)
+ out.addQuestion(DNSQuestion(self.type, _TYPE_PTR, _CLASS_IN))
+ for record in self.services.values():
+ if not record.isExpired(now):
+ out.addAnswerAtTime(record, now)
+ self.zeroconf.send(out)
+ self.nextTime = now + self.delay
+ self.delay = min(20 * 1000, self.delay * 2)
+
+ if len(self.list) > 0:
+ event = self.list.pop(0)
+
+ if event is not None:
+ event(self.zeroconf)
+
+
+class ServiceInfo(object):
+ """Service information"""
+
+ def __init__(self, type, name, address=None, port=None, weight=0, priority=0, properties=None, server=None):
+ """Create a service description.
+
+ type: fully qualified service type name
+ name: fully qualified service name
+ address: IP address as unsigned short, network byte order
+ port: port that the service runs on
+ weight: weight of the service
+ priority: priority of the service
+ properties: dictionary of properties (or a string holding the bytes for the text field)
+ server: fully qualified name for service host (defaults to name)"""
+
+ if not name.endswith(type):
+ raise BadTypeInNameException
+ self.type = type
+ self.name = name
+ self.address = address
+ self.port = port
+ self.weight = weight
+ self.priority = priority
+ if server:
+ self.server = server
+ else:
+ self.server = name
+ self.setProperties(properties)
+
+ def setProperties(self, properties):
+ """Sets properties and text of this info from a dictionary"""
+ if isinstance(properties, dict):
+ self.properties = properties
+ list = []
+ result = ''
+ for key in properties:
+ value = properties[key]
+ if value is None:
+ suffix = ''.encode('utf-8')
+ elif isinstance(value, str):
+ suffix = value.encode('utf-8')
+ elif isinstance(value, int):
+ if value:
+ suffix = 'true'
+ else:
+ suffix = 'false'
+ else:
+ suffix = ''.encode('utf-8')
+ list.append('='.join((key, suffix)))
+ for item in list:
+ result = ''.join((result, struct.pack('!c', chr(len(item))), item))
+ self.text = result
+ else:
+ self.text = properties
+
+ def setText(self, text):
+ """Sets properties and text given a text field"""
+ self.text = text
+ try:
+ result = {}
+ end = len(text)
+ index = 0
+ strs = []
+ while index < end:
+ length = ord(text[index])
+ index += 1
+ strs.append(text[index:index+length])
+ index += length
+
+ for s in strs:
+ eindex = s.find('=')
+ if eindex == -1:
+ # No equals sign at all
+ key = s
+ value = 0
+ else:
+ key = s[:eindex]
+ value = s[eindex+1:]
+ if value == 'true':
+ value = 1
+ elif value == 'false' or not value:
+ value = 0
+
+ # Only update non-existent properties
+ if key and result.get(key) == None:
+ result[key] = value
+
+ self.properties = result
+ except:
+ traceback.print_exc()
+ self.properties = None
+
+ def getType(self):
+ """Type accessor"""
+ return self.type
+
+ def getName(self):
+ """Name accessor"""
+ if self.type is not None and self.name.endswith("." + self.type):
+ return self.name[:len(self.name) - len(self.type) - 1]
+ return self.name
+
+ def getAddress(self):
+ """Address accessor"""
+ return self.address
+
+ def getPort(self):
+ """Port accessor"""
+ return self.port
+
+ def getPriority(self):
+ """Pirority accessor"""
+ return self.priority
+
+ def getWeight(self):
+ """Weight accessor"""
+ return self.weight
+
+ def getProperties(self):
+ """Properties accessor"""
+ return self.properties
+
+ def getText(self):
+ """Text accessor"""
+ return self.text
+
+ def getServer(self):
+ """Server accessor"""
+ return self.server
+
+ def updateRecord(self, zeroconf, now, record):
+ """Updates service information from a DNS record"""
+ if record is not None and not record.isExpired(now):
+ if record.type == _TYPE_A:
+ if record.name == self.name:
+ self.address = record.address
+ elif record.type == _TYPE_SRV:
+ if record.name == self.name:
+ self.server = record.server
+ self.port = record.port
+ self.weight = record.weight
+ self.priority = record.priority
+ self.address = None
+ self.updateRecord(zeroconf, now, zeroconf.cache.getByDetails(self.server, _TYPE_A, _CLASS_IN))
+ elif record.type == _TYPE_TXT:
+ if record.name == self.name:
+ self.setText(record.text)
+
+ def request(self, zeroconf, timeout):
+ """Returns true if the service could be discovered on the
+ network, and updates this object with details discovered.
+ """
+ now = currentTimeMillis()
+ delay = _LISTENER_TIME
+ next = now + delay
+ last = now + timeout
+ result = 0
+ try:
+ zeroconf.addListener(self, DNSQuestion(self.name, _TYPE_ANY, _CLASS_IN))
+ while self.server is None or self.address is None or self.text is None:
+ if last <= now:
+ return 0
+ if next <= now:
+ out = DNSOutgoing(_FLAGS_QR_QUERY)
+ out.addQuestion(DNSQuestion(self.name, _TYPE_SRV, _CLASS_IN))
+ out.addAnswerAtTime(zeroconf.cache.getByDetails(self.name, _TYPE_SRV, _CLASS_IN), now)
+ out.addQuestion(DNSQuestion(self.name, _TYPE_TXT, _CLASS_IN))
+ out.addAnswerAtTime(zeroconf.cache.getByDetails(self.name, _TYPE_TXT, _CLASS_IN), now)
+ if self.server is not None:
+ out.addQuestion(DNSQuestion(self.server, _TYPE_A, _CLASS_IN))
+ out.addAnswerAtTime(zeroconf.cache.getByDetails(self.server, _TYPE_A, _CLASS_IN), now)
+ zeroconf.send(out)
+ next = now + delay
+ delay = delay * 2
+
+ zeroconf.wait(min(next, last) - now)
+ now = currentTimeMillis()
+ result = 1
+ finally:
+ zeroconf.removeListener(self)
+
+ return result
+
+ def __eq__(self, other):
+ """Tests equality of service name"""
+ if isinstance(other, ServiceInfo):
+ return other.name == self.name
+ return 0
+
+ def __ne__(self, other):
+ """Non-equality test"""
+ return not self.__eq__(other)
+
+ def __repr__(self):
+ """String representation"""
+ result = "service[%s,%s:%s," % (self.name, socket.inet_ntoa(self.getAddress()), self.port)
+ if self.text is None:
+ result += "None"
+ else:
+ if len(self.text) < 20:
+ result += self.text
+ else:
+ result += self.text[:17] + "..."
+ result += "]"
+ return result
+
+
+class Zeroconf(object):
+ """Implementation of Zeroconf Multicast DNS Service Discovery
+
+ Supports registration, unregistration, queries and browsing.
+ """
+ def __init__(self, bindaddress=None):
+ """Creates an instance of the Zeroconf class, establishing
+ multicast communications, listening and reaping threads."""
+ globals()['_GLOBAL_DONE'] = 0
+ if bindaddress is None:
+ self.intf = socket.gethostbyname(socket.gethostname())
+ else:
+ self.intf = bindaddress
+ self.group = ('', _MDNS_PORT)
+ self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+ try:
+ self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+ self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+ except:
+ # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
+ # multicast UDP sockets (p 731, "TCP/IP Illustrated,
+ # Volume 2"), but some BSD-derived systems require
+ # SO_REUSEPORT to be specified explicity. Also, not all
+ # versions of Python have SO_REUSEPORT available. So
+ # if you're on a BSD-based system, and haven't upgraded
+ # to Python 2.3 yet, you may find this library doesn't
+ # work as expected.
+ #
+ pass
+ self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_TTL, 255)
+ self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)
+ try:
+ self.socket.bind(self.group)
+ except:
+ # Some versions of linux raise an exception even though
+ # the SO_REUSE* options have been set, so ignore it
+ #
+ pass
+ self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(self.intf) + socket.inet_aton('0.0.0.0'))
+ self.socket.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(_MDNS_ADDR) + socket.inet_aton('0.0.0.0'))
+
+ self.listeners = []
+ self.browsers = []
+ self.services = {}
+
+ self.cache = DNSCache()
+
+ self.condition = threading.Condition()
+
+ self.engine = Engine(self)
+ self.listener = Listener(self)
+ self.reaper = Reaper(self)
+
+ def isLoopback(self):
+ return self.intf.startswith("127.0.0.1")
+
+ def isLinklocal(self):
+ return self.intf.startswith("169.254.")
+
+ def wait(self, timeout):
+ """Calling thread waits for a given number of milliseconds or
+ until notified."""
+ self.condition.acquire()
+ self.condition.wait(timeout/1000)
+ self.condition.release()
+
+ def notifyAll(self):
+ """Notifies all waiting threads"""
+ self.condition.acquire()
+ self.condition.notifyAll()
+ self.condition.release()
+
+ def getServiceInfo(self, type, name, timeout=3000):
+ """Returns network's service information for a particular
+ name and type, or None if no service matches by the timeout,
+ which defaults to 3 seconds."""
+ info = ServiceInfo(type, name)
+ if info.request(self, timeout):
+ return info
+ return None
+
+ def addServiceListener(self, type, listener):
+ """Adds a listener for a particular service type. This object
+ will then have its updateRecord method called when information
+ arrives for that type."""
+ self.removeServiceListener(listener)
+ self.browsers.append(ServiceBrowser(self, type, listener))
+
+ def removeServiceListener(self, listener):
+ """Removes a listener from the set that is currently listening."""
+ for browser in self.browsers:
+ if browser.listener == listener:
+ browser.cancel()
+ del(browser)
+
+ def registerService(self, info, ttl=_DNS_TTL):
+ """Registers service information to the network with a default TTL
+ of 60 seconds. Zeroconf will then respond to requests for
+ information for that service. The name of the service may be
+ changed if needed to make it unique on the network."""
+ self.checkService(info)
+ self.services[info.name.lower()] = info
+ now = currentTimeMillis()
+ nextTime = now
+ i = 0
+ while i < 3:
+ if now < nextTime:
+ self.wait(nextTime - now)
+ now = currentTimeMillis()
+ continue
+ out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
+ out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, ttl, info.name), 0)
+ out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, ttl, info.priority, info.weight, info.port, info.server), 0)
+ out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, ttl, info.text), 0)
+ if info.address:
+ out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, ttl, info.address), 0)
+ self.send(out)
+ i += 1
+ nextTime += _REGISTER_TIME
+
+ def unregisterService(self, info):
+ """Unregister a service."""
+ try:
+ del(self.services[info.name.lower()])
+ except:
+ pass
+ now = currentTimeMillis()
+ nextTime = now
+ i = 0
+ while i < 3:
+ if now < nextTime:
+ self.wait(nextTime - now)
+ now = currentTimeMillis()
+ continue
+ out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
+ out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, 0, info.name), 0)
+ out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, 0, info.priority, info.weight, info.port, info.name), 0)
+ out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, 0, info.text), 0)
+ if info.address:
+ out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, 0, info.address), 0)
+ self.send(out)
+ i += 1
+ nextTime += _UNREGISTER_TIME
+
+ def unregisterAllServices(self):
+ """Unregister all registered services."""
+ if len(self.services) > 0:
+ now = currentTimeMillis()
+ nextTime = now
+ i = 0
+ while i < 3:
+ if now < nextTime:
+ self.wait(nextTime - now)
+ now = currentTimeMillis()
+ continue
+ out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
+ for info in self.services.values():
+ out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, 0, info.name), 0)
+ out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, 0, info.priority, info.weight, info.port, info.server), 0)
+ out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, 0, info.text), 0)
+ if info.address:
+ out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, 0, info.address), 0)
+ self.send(out)
+ i += 1
+ nextTime += _UNREGISTER_TIME
+
+ def checkService(self, info):
+ """Checks the network for a unique service name, modifying the
+ ServiceInfo passed in if it is not unique."""
+ now = currentTimeMillis()
+ nextTime = now
+ i = 0
+ while i < 3:
+ for record in self.cache.entriesWithName(info.type):
+ if record.type == _TYPE_PTR and not record.isExpired(now) and record.alias == info.name:
+ if (info.name.find('.') < 0):
+ info.name = info.name + ".[" + info.address + ":" + info.port + "]." + info.type
+ self.checkService(info)
+ return
+ raise NonUniqueNameException
+ if now < nextTime:
+ self.wait(nextTime - now)
+ now = currentTimeMillis()
+ continue
+ out = DNSOutgoing(_FLAGS_QR_QUERY | _FLAGS_AA)
+ self.debug = out
+ out.addQuestion(DNSQuestion(info.type, _TYPE_PTR, _CLASS_IN))
+ out.addAuthorativeAnswer(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, _DNS_TTL, info.name))
+ self.send(out)
+ i += 1
+ nextTime += _CHECK_TIME
+
+ def addListener(self, listener, question):
+ """Adds a listener for a given question. The listener will have
+ its updateRecord method called when information is available to
+ answer the question."""
+ now = currentTimeMillis()
+ self.listeners.append(listener)
+ if question is not None:
+ for record in self.cache.entriesWithName(question.name):
+ if question.answeredBy(record) and not record.isExpired(now):
+ listener.updateRecord(self, now, record)
+ self.notifyAll()
+
+ def removeListener(self, listener):
+ """Removes a listener."""
+ try:
+ self.listeners.remove(listener)
+ self.notifyAll()
+ except:
+ pass
+
+ def updateRecord(self, now, rec):
+ """Used to notify listeners of new information that has updated
+ a record."""
+ for listener in self.listeners:
+ listener.updateRecord(self, now, rec)
+ self.notifyAll()
+
+ def handleResponse(self, msg):
+ """Deal with incoming response packets. All answers
+ are held in the cache, and listeners are notified."""
+ now = currentTimeMillis()
+ for record in msg.answers:
+ expired = record.isExpired(now)
+ if record in self.cache.entries():
+ if expired:
+ self.cache.remove(record)
+ else:
+ entry = self.cache.get(record)
+ if entry is not None:
+ entry.resetTTL(record)
+ record = entry
+ else:
+ self.cache.add(record)
+
+ self.updateRecord(now, record)
+
+ def handleQuery(self, msg, addr, port):
+ """Deal with incoming query packets. Provides a response if
+ possible."""
+ out = None
+
+ # Support unicast client responses
+ #
+ if port != _MDNS_PORT:
+ out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA, 0)
+ for question in msg.questions:
+ out.addQuestion(question)
+
+ for question in msg.questions:
+ if question.type == _TYPE_PTR:
+ for service in self.services.values():
+ if question.name == service.type:
+ if out is None:
+ out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
+ out.addAnswer(msg, DNSPointer(service.type, _TYPE_PTR, _CLASS_IN, _DNS_TTL, service.name))
+ else:
+ try:
+ if out is None:
+ out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
+
+ # Answer A record queries for any service addresses we know
+ if question.type == _TYPE_A or question.type == _TYPE_ANY:
+ for service in self.services.values():
+ if service.server == question.name.lower():
+ out.addAnswer(msg, DNSAddress(question.name, _TYPE_A, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.address))
+
+ service = self.services.get(question.name.lower(), None)
+ if not service: continue
+
+ if question.type == _TYPE_SRV or question.type == _TYPE_ANY:
+ out.addAnswer(msg, DNSService(question.name, _TYPE_SRV, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.priority, service.weight, service.port, service.server))
+ if question.type == _TYPE_TXT or question.type == _TYPE_ANY:
+ out.addAnswer(msg, DNSText(question.name, _TYPE_TXT, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.text))
+ if question.type == _TYPE_SRV:
+ out.addAdditionalAnswer(DNSAddress(service.server, _TYPE_A, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.address))
+ except:
+ traceback.print_exc()
+
+ if out is not None and out.answers:
+ out.id = msg.id
+ self.send(out, addr, port)
+
+ def send(self, out, addr = _MDNS_ADDR, port = _MDNS_PORT):
+ """Sends an outgoing packet."""
+ # This is a quick test to see if we can parse the packets we generate
+ #temp = DNSIncoming(out.packet())
+ try:
+ bytes_sent = self.socket.sendto(out.packet(), 0, (addr, port))
+ except:
+ # Ignore this, it may be a temporary loss of network connection
+ pass
+
+ def close(self):
+ """Ends the background threads, and prevent this instance from
+ servicing further queries."""
+ if globals()['_GLOBAL_DONE'] == 0:
+ globals()['_GLOBAL_DONE'] = 1
+ self.notifyAll()
+ self.engine.notify()
+ self.unregisterAllServices()
+ self.socket.setsockopt(socket.SOL_IP, socket.IP_DROP_MEMBERSHIP, socket.inet_aton(_MDNS_ADDR) + socket.inet_aton('0.0.0.0'))
+ self.socket.close()
+
+# Test a few module features, including service registration, service
+# query (for Zoe), and service unregistration.
+
+if __name__ == '__main__':
+ print "Multicast DNS Service Discovery for Python, version", __version__
+ r = Zeroconf()
+ print "1. Testing registration of a service..."
+ desc = {'version':'0.10','a':'test value', 'b':'another value'}
+ info = ServiceInfo("_http._tcp.local.", "My Service Name._http._tcp.local.", socket.inet_aton("127.0.0.1"), 1234, 0, 0, desc)
+ print " Registering service..."
+ r.registerService(info)
+ print " Registration done."
+ print "2. Testing query of service information..."
+ print " Getting ZOE service:", str(r.getServiceInfo("_http._tcp.local.", "ZOE._http._tcp.local."))
+ print " Query done."
+ print "3. Testing query of own service..."
+ print " Getting self:", str(r.getServiceInfo("_http._tcp.local.", "My Service Name._http._tcp.local."))
+ print " Query done."
+ print "4. Testing unregister of service information..."
+ r.unregisterService(info)
+ print " Unregister done."
+ r.close()