etisserant@203: """ Multicast DNS Service Discovery for Python, v0.12
etisserant@203: Copyright (C) 2003, Paul Scott-Murphy
etisserant@203:
etisserant@203: This module provides a framework for the use of DNS Service Discovery
etisserant@203: using IP multicast. It has been tested against the JRendezvous
etisserant@203: implementation from <a href="http://strangeberry.com">StrangeBerry</a>,
etisserant@203: and against the mDNSResponder from Mac OS X 10.3.8.
etisserant@203:
etisserant@203: This library is free software; you can redistribute it and/or
etisserant@203: modify it under the terms of the GNU Lesser General Public
etisserant@203: License as published by the Free Software Foundation; either
etisserant@203: version 2.1 of the License, or (at your option) any later version.
etisserant@203:
etisserant@203: This library is distributed in the hope that it will be useful,
etisserant@203: but WITHOUT ANY WARRANTY; without even the implied warranty of
etisserant@203: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
etisserant@203: Lesser General Public License for more details.
etisserant@203:
etisserant@203: You should have received a copy of the GNU Lesser General Public
etisserant@203: License along with this library; if not, write to the Free Software
etisserant@203: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
etisserant@223:
etisserant@203: """
etisserant@203:
etisserant@203: """0.12 update - allow selection of binding interface
etisserant@223: typo fix - Thanks A. M. Kuchlingi
etisserant@223: removed all use of word 'Rendezvous' - this is an API change"""
etisserant@203:
etisserant@203: """0.11 update - correction to comments for addListener method
etisserant@203: support for new record types seen from OS X
etisserant@223: - IPv6 address
etisserant@223: - hostinfo
etisserant@223: ignore unknown DNS record types
etisserant@223: fixes to name decoding
etisserant@223: works alongside other processes using port 5353 (e.g. on Mac OS X)
etisserant@223: tested against Mac OS X 10.3.2's mDNSResponder
etisserant@223: corrections to removal of list entries for service browser"""
etisserant@203:
etisserant@203: """0.10 update - Jonathon Paisley contributed these corrections:
etisserant@203: always multicast replies, even when query is unicast
etisserant@223: correct a pointer encoding problem
etisserant@223: can now write records in any order
etisserant@223: traceback shown on failure
etisserant@223: better TXT record parsing
etisserant@223: server is now separate from name
etisserant@223: can cancel a service browser
etisserant@223:
etisserant@223: modified some unit tests to accommodate these changes"""
etisserant@203:
etisserant@203: """0.09 update - remove all records on service unregistration
etisserant@203: fix DOS security problem with readName"""
etisserant@203:
etisserant@203: """0.08 update - changed licensing to LGPL"""
etisserant@203:
etisserant@203: """0.07 update - faster shutdown on engine
etisserant@203: pointer encoding of outgoing names
etisserant@223: ServiceBrowser now works
etisserant@223: new unit tests"""
etisserant@203:
etisserant@203: """0.06 update - small improvements with unit tests
etisserant@203: added defined exception types
etisserant@223: new style objects
etisserant@223: fixed hostname/interface problem
etisserant@223: fixed socket timeout problem
etisserant@223: fixed addServiceListener() typo bug
etisserant@223: using select() for socket reads
etisserant@223: tested on Debian unstable with Python 2.2.2"""
etisserant@203:
etisserant@203: """0.05 update - ensure case insensitivty on domain names
etisserant@203: support for unicast DNS queries"""
etisserant@203:
etisserant@203: """0.04 update - added some unit tests
etisserant@203: added __ne__ adjuncts where required
etisserant@223: ensure names end in '.local.'
etisserant@223: timeout on receiving socket for clean shutdown"""
etisserant@203:
etisserant@203: __author__ = "Paul Scott-Murphy"
etisserant@203: __email__ = "paul at scott dash murphy dot com"
etisserant@203: __version__ = "0.12"
etisserant@203:
etisserant@203: import string
etisserant@203: import time
etisserant@203: import struct
etisserant@203: import socket
etisserant@203: import threading
etisserant@203: import select
etisserant@203: import traceback
etisserant@203:
etisserant@203: __all__ = ["Zeroconf", "ServiceInfo", "ServiceBrowser"]
etisserant@203:
etisserant@203: # hook for threads
etisserant@203:
etisserant@203: globals()['_GLOBAL_DONE'] = 0
etisserant@203:
etisserant@203: # Some timing constants
etisserant@203:
etisserant@203: _UNREGISTER_TIME = 125
etisserant@203: _CHECK_TIME = 175
etisserant@203: _REGISTER_TIME = 225
etisserant@203: _LISTENER_TIME = 200
etisserant@203: _BROWSER_TIME = 500
etisserant@203:
etisserant@203: # Some DNS constants
etisserant@223:
etisserant@203: _MDNS_ADDR = '224.0.0.251'
etisserant@203: _MDNS_PORT = 5353;
etisserant@203: _DNS_PORT = 53;
etisserant@203: _DNS_TTL = 60 * 60; # one hour default TTL
etisserant@203:
etisserant@203: _MAX_MSG_TYPICAL = 1460 # unused
etisserant@203: _MAX_MSG_ABSOLUTE = 8972
etisserant@203:
etisserant@203: _FLAGS_QR_MASK = 0x8000 # query response mask
etisserant@203: _FLAGS_QR_QUERY = 0x0000 # query
etisserant@203: _FLAGS_QR_RESPONSE = 0x8000 # response
etisserant@203:
etisserant@203: _FLAGS_AA = 0x0400 # Authorative answer
etisserant@203: _FLAGS_TC = 0x0200 # Truncated
etisserant@203: _FLAGS_RD = 0x0100 # Recursion desired
etisserant@203: _FLAGS_RA = 0x8000 # Recursion available
etisserant@203:
etisserant@203: _FLAGS_Z = 0x0040 # Zero
etisserant@203: _FLAGS_AD = 0x0020 # Authentic data
etisserant@203: _FLAGS_CD = 0x0010 # Checking disabled
etisserant@203:
etisserant@203: _CLASS_IN = 1
etisserant@203: _CLASS_CS = 2
etisserant@203: _CLASS_CH = 3
etisserant@203: _CLASS_HS = 4
etisserant@203: _CLASS_NONE = 254
etisserant@203: _CLASS_ANY = 255
etisserant@203: _CLASS_MASK = 0x7FFF
etisserant@203: _CLASS_UNIQUE = 0x8000
etisserant@203:
etisserant@203: _TYPE_A = 1
etisserant@203: _TYPE_NS = 2
etisserant@203: _TYPE_MD = 3
etisserant@203: _TYPE_MF = 4
etisserant@203: _TYPE_CNAME = 5
etisserant@203: _TYPE_SOA = 6
etisserant@203: _TYPE_MB = 7
etisserant@203: _TYPE_MG = 8
etisserant@203: _TYPE_MR = 9
etisserant@203: _TYPE_NULL = 10
etisserant@203: _TYPE_WKS = 11
etisserant@203: _TYPE_PTR = 12
etisserant@203: _TYPE_HINFO = 13
etisserant@203: _TYPE_MINFO = 14
etisserant@203: _TYPE_MX = 15
etisserant@203: _TYPE_TXT = 16
etisserant@203: _TYPE_AAAA = 28
etisserant@203: _TYPE_SRV = 33
etisserant@203: _TYPE_ANY = 255
etisserant@203:
etisserant@203: # Mapping constants to names
etisserant@203:
etisserant@203: _CLASSES = { _CLASS_IN : "in",
etisserant@223: _CLASS_CS : "cs",
etisserant@223: _CLASS_CH : "ch",
etisserant@223: _CLASS_HS : "hs",
etisserant@223: _CLASS_NONE : "none",
etisserant@223: _CLASS_ANY : "any" }
etisserant@203:
etisserant@203: _TYPES = { _TYPE_A : "a",
etisserant@223: _TYPE_NS : "ns",
etisserant@223: _TYPE_MD : "md",
etisserant@223: _TYPE_MF : "mf",
etisserant@223: _TYPE_CNAME : "cname",
etisserant@223: _TYPE_SOA : "soa",
etisserant@223: _TYPE_MB : "mb",
etisserant@223: _TYPE_MG : "mg",
etisserant@223: _TYPE_MR : "mr",
etisserant@223: _TYPE_NULL : "null",
etisserant@223: _TYPE_WKS : "wks",
etisserant@223: _TYPE_PTR : "ptr",
etisserant@223: _TYPE_HINFO : "hinfo",
etisserant@223: _TYPE_MINFO : "minfo",
etisserant@223: _TYPE_MX : "mx",
etisserant@223: _TYPE_TXT : "txt",
etisserant@223: _TYPE_AAAA : "quada",
etisserant@223: _TYPE_SRV : "srv",
etisserant@223: _TYPE_ANY : "any" }
etisserant@203:
etisserant@203: # utility functions
etisserant@203:
etisserant@203: def currentTimeMillis():
etisserant@223: """Current system time in milliseconds"""
etisserant@223: return time.time() * 1000
etisserant@203:
etisserant@203: # Exceptions
etisserant@203:
etisserant@203: class NonLocalNameException(Exception):
etisserant@223: pass
etisserant@203:
etisserant@203: class NonUniqueNameException(Exception):
etisserant@223: pass
etisserant@203:
etisserant@203: class NamePartTooLongException(Exception):
etisserant@223: pass
etisserant@203:
etisserant@203: class AbstractMethodException(Exception):
etisserant@223: pass
etisserant@203:
etisserant@203: class BadTypeInNameException(Exception):
etisserant@223: pass
etisserant@203:
etisserant@203: # implementation classes
etisserant@203:
etisserant@203: class DNSEntry(object):
etisserant@223: """A DNS entry"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz):
etisserant@223: self.key = string.lower(name)
etisserant@223: self.name = name
etisserant@223: self.type = type
etisserant@223: self.clazz = clazz & _CLASS_MASK
etisserant@223: self.unique = (clazz & _CLASS_UNIQUE) != 0
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Equality test on name, type, and class"""
etisserant@223: if isinstance(other, DNSEntry):
etisserant@223: return self.name == other.name and self.type == other.type and self.clazz == other.clazz
etisserant@223: return 0
etisserant@223:
etisserant@223: def __ne__(self, other):
etisserant@223: """Non-equality test"""
etisserant@223: return not self.__eq__(other)
etisserant@223:
etisserant@223: def getClazz(self, clazz):
etisserant@223: """Class accessor"""
etisserant@223: try:
etisserant@223: return _CLASSES[clazz]
etisserant@223: except:
etisserant@223: return "?(%s)" % (clazz)
etisserant@223:
etisserant@223: def getType(self, type):
etisserant@223: """Type accessor"""
etisserant@223: try:
etisserant@223: return _TYPES[type]
etisserant@223: except:
etisserant@223: return "?(%s)" % (type)
etisserant@223:
etisserant@223: def toString(self, hdr, other):
etisserant@223: """String representation with additional information"""
etisserant@223: result = "%s[%s,%s" % (hdr, self.getType(self.type), self.getClazz(self.clazz))
etisserant@223: if self.unique:
etisserant@223: result += "-unique,"
etisserant@223: else:
etisserant@223: result += ","
etisserant@223: result += self.name
etisserant@223: if other is not None:
etisserant@223: result += ",%s]" % (other)
etisserant@223: else:
etisserant@223: result += "]"
etisserant@223: return result
etisserant@203:
etisserant@203: class DNSQuestion(DNSEntry):
etisserant@223: """A DNS question entry"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz):
etisserant@223: if not name.endswith(".local."):
etisserant@223: raise NonLocalNameException
etisserant@223: DNSEntry.__init__(self, name, type, clazz)
etisserant@223:
etisserant@223: def answeredBy(self, rec):
etisserant@223: """Returns true if the question is answered by the record"""
etisserant@223: return self.clazz == rec.clazz and (self.type == rec.type or self.type == _TYPE_ANY) and self.name == rec.name
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: return DNSEntry.toString(self, "question", None)
etisserant@203:
etisserant@203:
etisserant@203: class DNSRecord(DNSEntry):
etisserant@223: """A DNS record - like a DNS entry, but has a TTL"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz, ttl):
etisserant@223: DNSEntry.__init__(self, name, type, clazz)
etisserant@223: self.ttl = ttl
etisserant@223: self.created = currentTimeMillis()
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality as per DNSRecord"""
etisserant@223: if isinstance(other, DNSRecord):
etisserant@223: return DNSEntry.__eq__(self, other)
etisserant@223: return 0
etisserant@223:
etisserant@223: def suppressedBy(self, msg):
etisserant@223: """Returns true if any answer in a message can suffice for the
etisserant@223: information held in this record."""
etisserant@223: for record in msg.answers:
etisserant@223: if self.suppressedByAnswer(record):
etisserant@223: return 1
etisserant@223: return 0
etisserant@223:
etisserant@223: def suppressedByAnswer(self, other):
etisserant@223: """Returns true if another record has same name, type and class,
etisserant@223: and if its TTL is at least half of this record's."""
etisserant@223: if self == other and other.ttl > (self.ttl / 2):
etisserant@223: return 1
etisserant@223: return 0
etisserant@223:
etisserant@223: def getExpirationTime(self, percent):
etisserant@223: """Returns the time at which this record will have expired
etisserant@223: by a certain percentage."""
etisserant@223: return self.created + (percent * self.ttl * 10)
etisserant@223:
etisserant@223: def getRemainingTTL(self, now):
etisserant@223: """Returns the remaining TTL in seconds."""
etisserant@223: return max(0, (self.getExpirationTime(100) - now) / 1000)
etisserant@223:
etisserant@223: def isExpired(self, now):
etisserant@223: """Returns true if this record has expired."""
etisserant@223: return self.getExpirationTime(100) <= now
etisserant@223:
etisserant@223: def isStale(self, now):
etisserant@223: """Returns true if this record is at least half way expired."""
etisserant@223: return self.getExpirationTime(50) <= now
etisserant@223:
etisserant@223: def resetTTL(self, other):
etisserant@223: """Sets this record's TTL and created time to that of
etisserant@223: another record."""
etisserant@223: self.created = other.created
etisserant@223: self.ttl = other.ttl
etisserant@223:
etisserant@223: def write(self, out):
etisserant@223: """Abstract method"""
etisserant@223: raise AbstractMethodException
etisserant@223:
etisserant@223: def toString(self, other):
etisserant@223: """String representation with addtional information"""
etisserant@223: arg = "%s/%s,%s" % (self.ttl, self.getRemainingTTL(currentTimeMillis()), other)
etisserant@223: return DNSEntry.toString(self, "record", arg)
etisserant@203:
etisserant@203: class DNSAddress(DNSRecord):
etisserant@223: """A DNS address record"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz, ttl, address):
etisserant@223: DNSRecord.__init__(self, name, type, clazz, ttl)
etisserant@223: self.address = address
etisserant@223:
etisserant@223: def write(self, out):
etisserant@223: """Used in constructing an outgoing packet"""
etisserant@223: out.writeString(self.address, len(self.address))
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality on address"""
etisserant@223: if isinstance(other, DNSAddress):
etisserant@223: return self.address == other.address
etisserant@223: return 0
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: try:
etisserant@223: return socket.inet_ntoa(self.address)
etisserant@223: except:
etisserant@223: return self.address
etisserant@203:
etisserant@203: class DNSHinfo(DNSRecord):
etisserant@223: """A DNS host information record"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz, ttl, cpu, os):
etisserant@223: DNSRecord.__init__(self, name, type, clazz, ttl)
etisserant@223: self.cpu = cpu
etisserant@223: self.os = os
etisserant@223:
etisserant@223: def write(self, out):
etisserant@223: """Used in constructing an outgoing packet"""
etisserant@223: out.writeString(self.cpu, len(self.cpu))
etisserant@223: out.writeString(self.os, len(self.os))
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality on cpu and os"""
etisserant@223: if isinstance(other, DNSHinfo):
etisserant@223: return self.cpu == other.cpu and self.os == other.os
etisserant@223: return 0
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: return self.cpu + " " + self.os
etisserant@223:
etisserant@203: class DNSPointer(DNSRecord):
etisserant@223: """A DNS pointer record"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz, ttl, alias):
etisserant@223: DNSRecord.__init__(self, name, type, clazz, ttl)
etisserant@223: self.alias = alias
etisserant@223:
etisserant@223: def write(self, out):
etisserant@223: """Used in constructing an outgoing packet"""
etisserant@223: out.writeName(self.alias)
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality on alias"""
etisserant@223: if isinstance(other, DNSPointer):
etisserant@223: return self.alias == other.alias
etisserant@223: return 0
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: return self.toString(self.alias)
etisserant@203:
etisserant@203: class DNSText(DNSRecord):
etisserant@223: """A DNS text record"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz, ttl, text):
etisserant@223: DNSRecord.__init__(self, name, type, clazz, ttl)
etisserant@223: self.text = text
etisserant@223:
etisserant@223: def write(self, out):
etisserant@223: """Used in constructing an outgoing packet"""
etisserant@223: out.writeString(self.text, len(self.text))
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality on text"""
etisserant@223: if isinstance(other, DNSText):
etisserant@223: return self.text == other.text
etisserant@223: return 0
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: if len(self.text) > 10:
etisserant@223: return self.toString(self.text[:7] + "...")
etisserant@223: else:
etisserant@223: return self.toString(self.text)
etisserant@203:
etisserant@203: class DNSService(DNSRecord):
etisserant@223: """A DNS service record"""
etisserant@223:
etisserant@223: def __init__(self, name, type, clazz, ttl, priority, weight, port, server):
etisserant@223: DNSRecord.__init__(self, name, type, clazz, ttl)
etisserant@223: self.priority = priority
etisserant@223: self.weight = weight
etisserant@223: self.port = port
etisserant@223: self.server = server
etisserant@223:
etisserant@223: def write(self, out):
etisserant@223: """Used in constructing an outgoing packet"""
etisserant@223: out.writeShort(self.priority)
etisserant@223: out.writeShort(self.weight)
etisserant@223: out.writeShort(self.port)
etisserant@223: out.writeName(self.server)
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality on priority, weight, port and server"""
etisserant@223: if isinstance(other, DNSService):
etisserant@223: return self.priority == other.priority and self.weight == other.weight and self.port == other.port and self.server == other.server
etisserant@223: return 0
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: return self.toString("%s:%s" % (self.server, self.port))
etisserant@203:
etisserant@203: class DNSIncoming(object):
etisserant@223: """Object representation of an incoming DNS packet"""
etisserant@223:
etisserant@223: def __init__(self, data):
etisserant@223: """Constructor from string holding bytes of packet"""
etisserant@223: self.offset = 0
etisserant@223: self.data = data
etisserant@223: self.questions = []
etisserant@223: self.answers = []
etisserant@223: self.numQuestions = 0
etisserant@223: self.numAnswers = 0
etisserant@223: self.numAuthorities = 0
etisserant@223: self.numAdditionals = 0
etisserant@223:
etisserant@223: self.readHeader()
etisserant@223: self.readQuestions()
etisserant@223: self.readOthers()
etisserant@223:
etisserant@223: def readHeader(self):
etisserant@223: """Reads header portion of packet"""
etisserant@223: format = '!HHHHHH'
etisserant@223: length = struct.calcsize(format)
etisserant@223: info = struct.unpack(format, self.data[self.offset:self.offset+length])
etisserant@223: self.offset += length
etisserant@223:
etisserant@223: self.id = info[0]
etisserant@223: self.flags = info[1]
etisserant@223: self.numQuestions = info[2]
etisserant@223: self.numAnswers = info[3]
etisserant@223: self.numAuthorities = info[4]
etisserant@223: self.numAdditionals = info[5]
etisserant@223:
etisserant@223: def readQuestions(self):
etisserant@223: """Reads questions section of packet"""
etisserant@223: format = '!HH'
etisserant@223: length = struct.calcsize(format)
etisserant@223: for i in range(0, self.numQuestions):
etisserant@223: name = self.readName()
etisserant@223: info = struct.unpack(format, self.data[self.offset:self.offset+length])
etisserant@223: self.offset += length
etisserant@223:
etisserant@223: question = DNSQuestion(name, info[0], info[1])
etisserant@223: self.questions.append(question)
etisserant@223:
etisserant@223: def readInt(self):
etisserant@223: """Reads an integer from the packet"""
etisserant@223: format = '!I'
etisserant@223: length = struct.calcsize(format)
etisserant@223: info = struct.unpack(format, self.data[self.offset:self.offset+length])
etisserant@223: self.offset += length
etisserant@223: return info[0]
etisserant@223:
etisserant@223: def readCharacterString(self):
etisserant@223: """Reads a character string from the packet"""
etisserant@223: length = ord(self.data[self.offset])
etisserant@223: self.offset += 1
etisserant@223: return self.readString(length)
etisserant@223:
etisserant@223: def readString(self, len):
etisserant@223: """Reads a string of a given length from the packet"""
etisserant@223: format = '!' + str(len) + 's'
etisserant@223: length = struct.calcsize(format)
etisserant@223: info = struct.unpack(format, self.data[self.offset:self.offset+length])
etisserant@223: self.offset += length
etisserant@223: return info[0]
etisserant@223:
etisserant@223: def readUnsignedShort(self):
etisserant@223: """Reads an unsigned short from the packet"""
etisserant@223: format = '!H'
etisserant@223: length = struct.calcsize(format)
etisserant@223: info = struct.unpack(format, self.data[self.offset:self.offset+length])
etisserant@223: self.offset += length
etisserant@223: return info[0]
etisserant@223:
etisserant@223: def readOthers(self):
etisserant@223: """Reads the answers, authorities and additionals section of the packet"""
etisserant@223: format = '!HHiH'
etisserant@223: length = struct.calcsize(format)
etisserant@223: n = self.numAnswers + self.numAuthorities + self.numAdditionals
etisserant@223: for i in range(0, n):
etisserant@223: domain = self.readName()
etisserant@223: info = struct.unpack(format, self.data[self.offset:self.offset+length])
etisserant@223: self.offset += length
etisserant@223:
etisserant@223: rec = None
etisserant@223: if info[0] == _TYPE_A:
etisserant@223: rec = DNSAddress(domain, info[0], info[1], info[2], self.readString(4))
etisserant@223: elif info[0] == _TYPE_CNAME or info[0] == _TYPE_PTR:
etisserant@223: rec = DNSPointer(domain, info[0], info[1], info[2], self.readName())
etisserant@223: elif info[0] == _TYPE_TXT:
etisserant@223: rec = DNSText(domain, info[0], info[1], info[2], self.readString(info[3]))
etisserant@223: elif info[0] == _TYPE_SRV:
etisserant@223: rec = DNSService(domain, info[0], info[1], info[2], self.readUnsignedShort(), self.readUnsignedShort(), self.readUnsignedShort(), self.readName())
etisserant@223: elif info[0] == _TYPE_HINFO:
etisserant@223: rec = DNSHinfo(domain, info[0], info[1], info[2], self.readCharacterString(), self.readCharacterString())
etisserant@223: elif info[0] == _TYPE_AAAA:
etisserant@223: rec = DNSAddress(domain, info[0], info[1], info[2], self.readString(16))
etisserant@223: else:
etisserant@223: # Try to ignore types we don't know about
etisserant@223: # this may mean the rest of the name is
etisserant@223: # unable to be parsed, and may show errors
etisserant@223: # so this is left for debugging. New types
etisserant@223: # encountered need to be parsed properly.
etisserant@223: #
etisserant@223: #print "UNKNOWN TYPE = " + str(info[0])
etisserant@223: #raise BadTypeInNameException
etisserant@223: pass
etisserant@223:
etisserant@223: if rec is not None:
etisserant@223: self.answers.append(rec)
etisserant@223:
etisserant@223: def isQuery(self):
etisserant@223: """Returns true if this is a query"""
etisserant@223: return (self.flags & _FLAGS_QR_MASK) == _FLAGS_QR_QUERY
etisserant@223:
etisserant@223: def isResponse(self):
etisserant@223: """Returns true if this is a response"""
etisserant@223: return (self.flags & _FLAGS_QR_MASK) == _FLAGS_QR_RESPONSE
etisserant@223:
etisserant@223: def readUTF(self, offset, len):
etisserant@223: """Reads a UTF-8 string of a given length from the packet"""
etisserant@223: result = self.data[offset:offset+len].decode('utf-8')
etisserant@223: return result
etisserant@223:
etisserant@223: def readName(self):
etisserant@223: """Reads a domain name from the packet"""
etisserant@223: result = ''
etisserant@223: off = self.offset
etisserant@223: next = -1
etisserant@223: first = off
etisserant@223:
etisserant@223: while 1:
etisserant@223: len = ord(self.data[off])
etisserant@223: off += 1
etisserant@223: if len == 0:
etisserant@223: break
etisserant@223: t = len & 0xC0
etisserant@223: if t == 0x00:
etisserant@223: result = ''.join((result, self.readUTF(off, len) + '.'))
etisserant@223: off += len
etisserant@223: elif t == 0xC0:
etisserant@223: if next < 0:
etisserant@223: next = off + 1
etisserant@223: off = ((len & 0x3F) << 8) | ord(self.data[off])
etisserant@223: if off >= first:
laurent@361: raise _("Bad domain name (circular) at ") + str(off)
etisserant@223: first = off
etisserant@223: else:
laurent@361: raise _("Bad domain name at ") + str(off)
etisserant@223:
etisserant@223: if next >= 0:
etisserant@223: self.offset = next
etisserant@223: else:
etisserant@223: self.offset = off
etisserant@223:
etisserant@223: return result
etisserant@223:
etisserant@223:
etisserant@203: class DNSOutgoing(object):
etisserant@223: """Object representation of an outgoing packet"""
etisserant@223:
etisserant@223: def __init__(self, flags, multicast = 1):
etisserant@223: self.finished = 0
etisserant@223: self.id = 0
etisserant@223: self.multicast = multicast
etisserant@223: self.flags = flags
etisserant@223: self.names = {}
etisserant@223: self.data = []
etisserant@223: self.size = 12
etisserant@223:
etisserant@223: self.questions = []
etisserant@223: self.answers = []
etisserant@223: self.authorities = []
etisserant@223: self.additionals = []
etisserant@223:
etisserant@223: def addQuestion(self, record):
etisserant@223: """Adds a question"""
etisserant@223: self.questions.append(record)
etisserant@223:
etisserant@223: def addAnswer(self, inp, record):
etisserant@223: """Adds an answer"""
etisserant@223: if not record.suppressedBy(inp):
etisserant@223: self.addAnswerAtTime(record, 0)
etisserant@223:
etisserant@223: def addAnswerAtTime(self, record, now):
etisserant@223: """Adds an answer if if does not expire by a certain time"""
etisserant@223: if record is not None:
etisserant@223: if now == 0 or not record.isExpired(now):
etisserant@223: self.answers.append((record, now))
etisserant@223:
etisserant@223: def addAuthorativeAnswer(self, record):
etisserant@223: """Adds an authoritative answer"""
etisserant@223: self.authorities.append(record)
etisserant@223:
etisserant@223: def addAdditionalAnswer(self, record):
etisserant@223: """Adds an additional answer"""
etisserant@223: self.additionals.append(record)
etisserant@223:
etisserant@223: def writeByte(self, value):
etisserant@223: """Writes a single byte to the packet"""
etisserant@223: format = '!c'
etisserant@223: self.data.append(struct.pack(format, chr(value)))
etisserant@223: self.size += 1
etisserant@223:
etisserant@223: def insertShort(self, index, value):
etisserant@223: """Inserts an unsigned short in a certain position in the packet"""
etisserant@223: format = '!H'
etisserant@223: self.data.insert(index, struct.pack(format, value))
etisserant@223: self.size += 2
etisserant@223:
etisserant@223: def writeShort(self, value):
etisserant@223: """Writes an unsigned short to the packet"""
etisserant@223: format = '!H'
etisserant@223: self.data.append(struct.pack(format, value))
etisserant@223: self.size += 2
etisserant@223:
etisserant@223: def writeInt(self, value):
etisserant@223: """Writes an unsigned integer to the packet"""
etisserant@223: format = '!I'
etisserant@223: self.data.append(struct.pack(format, int(value)))
etisserant@223: self.size += 4
etisserant@223:
etisserant@223: def writeString(self, value, length):
etisserant@223: """Writes a string to the packet"""
etisserant@223: format = '!' + str(length) + 's'
etisserant@223: self.data.append(struct.pack(format, value))
etisserant@223: self.size += length
etisserant@223:
etisserant@223: def writeUTF(self, s):
etisserant@223: """Writes a UTF-8 string of a given length to the packet"""
etisserant@223: utfstr = s.encode('utf-8')
etisserant@223: length = len(utfstr)
etisserant@223: if length > 64:
etisserant@223: raise NamePartTooLongException
etisserant@223: self.writeByte(length)
etisserant@223: self.writeString(utfstr, length)
etisserant@223:
etisserant@223: def writeName(self, name):
etisserant@223: """Writes a domain name to the packet"""
etisserant@223:
etisserant@223: try:
etisserant@223: # Find existing instance of this name in packet
etisserant@223: #
etisserant@223: index = self.names[name]
etisserant@223: except KeyError:
etisserant@223: # No record of this name already, so write it
etisserant@223: # out as normal, recording the location of the name
etisserant@223: # for future pointers to it.
etisserant@223: #
etisserant@223: self.names[name] = self.size
etisserant@223: parts = name.split('.')
etisserant@223: if parts[-1] == '':
etisserant@223: parts = parts[:-1]
etisserant@223: for part in parts:
etisserant@223: self.writeUTF(part)
etisserant@223: self.writeByte(0)
etisserant@223: return
etisserant@223:
etisserant@223: # An index was found, so write a pointer to it
etisserant@223: #
etisserant@223: self.writeByte((index >> 8) | 0xC0)
etisserant@223: self.writeByte(index)
etisserant@223:
etisserant@223: def writeQuestion(self, question):
etisserant@223: """Writes a question to the packet"""
etisserant@223: self.writeName(question.name)
etisserant@223: self.writeShort(question.type)
etisserant@223: self.writeShort(question.clazz)
etisserant@223:
etisserant@223: def writeRecord(self, record, now):
etisserant@223: """Writes a record (answer, authoritative answer, additional) to
etisserant@223: the packet"""
etisserant@223: self.writeName(record.name)
etisserant@223: self.writeShort(record.type)
etisserant@223: if record.unique and self.multicast:
etisserant@223: self.writeShort(record.clazz | _CLASS_UNIQUE)
etisserant@223: else:
etisserant@223: self.writeShort(record.clazz)
etisserant@223: if now == 0:
etisserant@223: self.writeInt(record.ttl)
etisserant@223: else:
etisserant@223: self.writeInt(record.getRemainingTTL(now))
etisserant@223: index = len(self.data)
etisserant@223: # Adjust size for the short we will write before this record
etisserant@223: #
etisserant@223: self.size += 2
etisserant@223: record.write(self)
etisserant@223: self.size -= 2
etisserant@223:
etisserant@223: length = len(''.join(self.data[index:]))
etisserant@223: self.insertShort(index, length) # Here is the short we adjusted for
etisserant@223:
etisserant@223: def packet(self):
etisserant@223: """Returns a string containing the packet's bytes
etisserant@223:
etisserant@223: No further parts should be added to the packet once this
etisserant@223: is done."""
etisserant@223: if not self.finished:
etisserant@223: self.finished = 1
etisserant@223: for question in self.questions:
etisserant@223: self.writeQuestion(question)
etisserant@223: for answer, time in self.answers:
etisserant@223: self.writeRecord(answer, time)
etisserant@223: for authority in self.authorities:
etisserant@223: self.writeRecord(authority, 0)
etisserant@223: for additional in self.additionals:
etisserant@223: self.writeRecord(additional, 0)
etisserant@223:
etisserant@223: self.insertShort(0, len(self.additionals))
etisserant@223: self.insertShort(0, len(self.authorities))
etisserant@223: self.insertShort(0, len(self.answers))
etisserant@223: self.insertShort(0, len(self.questions))
etisserant@223: self.insertShort(0, self.flags)
etisserant@223: if self.multicast:
etisserant@223: self.insertShort(0, 0)
etisserant@223: else:
etisserant@223: self.insertShort(0, self.id)
etisserant@223: return ''.join(self.data)
etisserant@203:
etisserant@203:
etisserant@203: class DNSCache(object):
etisserant@223: """A cache of DNS entries"""
etisserant@223:
etisserant@223: def __init__(self):
etisserant@223: self.cache = {}
etisserant@223:
etisserant@223: def add(self, entry):
etisserant@223: """Adds an entry"""
etisserant@223: try:
etisserant@223: list = self.cache[entry.key]
etisserant@223: except:
etisserant@223: list = self.cache[entry.key] = []
etisserant@223: list.append(entry)
etisserant@223:
etisserant@223: def remove(self, entry):
etisserant@223: """Removes an entry"""
etisserant@223: try:
etisserant@223: list = self.cache[entry.key]
etisserant@223: list.remove(entry)
etisserant@223: except:
etisserant@223: pass
etisserant@223:
etisserant@223: def get(self, entry):
etisserant@223: """Gets an entry by key. Will return None if there is no
etisserant@223: matching entry."""
etisserant@223: try:
etisserant@223: list = self.cache[entry.key]
etisserant@223: return list[list.index(entry)]
etisserant@223: except:
etisserant@223: return None
etisserant@223:
etisserant@223: def getByDetails(self, name, type, clazz):
etisserant@223: """Gets an entry by details. Will return None if there is
etisserant@223: no matching entry."""
etisserant@223: entry = DNSEntry(name, type, clazz)
etisserant@223: return self.get(entry)
etisserant@223:
etisserant@223: def entriesWithName(self, name):
etisserant@223: """Returns a list of entries whose key matches the name."""
etisserant@223: try:
etisserant@223: return self.cache[name]
etisserant@223: except:
etisserant@223: return []
etisserant@223:
etisserant@223: def entries(self):
etisserant@223: """Returns a list of all entries"""
etisserant@223: def add(x, y): return x+y
etisserant@223: try:
etisserant@223: return reduce(add, self.cache.values())
etisserant@223: except:
etisserant@223: return []
etisserant@203:
etisserant@203:
etisserant@203: class Engine(threading.Thread):
etisserant@223: """An engine wraps read access to sockets, allowing objects that
etisserant@223: need to receive data from sockets to be called back when the
etisserant@223: sockets are ready.
etisserant@223:
etisserant@223: A reader needs a handle_read() method, which is called when the socket
etisserant@223: it is interested in is ready for reading.
etisserant@223:
etisserant@223: Writers are not implemented here, because we only send short
etisserant@223: packets.
etisserant@223: """
etisserant@223:
etisserant@223: def __init__(self, zeroconf):
etisserant@223: threading.Thread.__init__(self)
etisserant@223: self.zeroconf = zeroconf
etisserant@223: self.readers = {} # maps socket to reader
etisserant@223: self.timeout = 5
etisserant@223: self.condition = threading.Condition()
etisserant@223: self.start()
etisserant@223:
etisserant@223: def run(self):
etisserant@223: while not globals()['_GLOBAL_DONE']:
etisserant@223: rs = self.getReaders()
etisserant@223: if len(rs) == 0:
etisserant@223: # No sockets to manage, but we wait for the timeout
etisserant@223: # or addition of a socket
etisserant@223: #
etisserant@223: self.condition.acquire()
etisserant@223: self.condition.wait(self.timeout)
etisserant@223: self.condition.release()
etisserant@223: else:
etisserant@223: try:
etisserant@223: rr, wr, er = select.select(rs, [], [], self.timeout)
etisserant@223: for socket in rr:
etisserant@223: try:
etisserant@223: self.readers[socket].handle_read()
etisserant@223: except:
Edouard@644: # Ignore errors that occur on shutdown
Edouard@644: pass
etisserant@223: except:
etisserant@223: pass
etisserant@223:
etisserant@223: def getReaders(self):
etisserant@223: result = []
etisserant@223: self.condition.acquire()
etisserant@223: result = self.readers.keys()
etisserant@223: self.condition.release()
etisserant@223: return result
etisserant@223:
etisserant@223: def addReader(self, reader, socket):
etisserant@223: self.condition.acquire()
etisserant@223: self.readers[socket] = reader
etisserant@223: self.condition.notify()
etisserant@223: self.condition.release()
etisserant@223:
etisserant@223: def delReader(self, socket):
etisserant@223: self.condition.acquire()
etisserant@223: del(self.readers[socket])
etisserant@223: self.condition.notify()
etisserant@223: self.condition.release()
etisserant@223:
etisserant@223: def notify(self):
etisserant@223: self.condition.acquire()
etisserant@223: self.condition.notify()
etisserant@223: self.condition.release()
etisserant@203:
etisserant@203: class Listener(object):
etisserant@223: """A Listener is used by this module to listen on the multicast
etisserant@223: group to which DNS messages are sent, allowing the implementation
etisserant@223: to cache information as it arrives.
etisserant@223:
etisserant@223: It requires registration with an Engine object in order to have
etisserant@223: the read() method called when a socket is availble for reading."""
etisserant@223:
etisserant@223: def __init__(self, zeroconf):
etisserant@223: self.zeroconf = zeroconf
etisserant@223: self.zeroconf.engine.addReader(self, self.zeroconf.socket)
etisserant@223:
etisserant@223: def handle_read(self):
etisserant@223: data, (addr, port) = self.zeroconf.socket.recvfrom(_MAX_MSG_ABSOLUTE)
etisserant@223: self.data = data
etisserant@223: msg = DNSIncoming(data)
etisserant@223: if msg.isQuery():
etisserant@223: # Always multicast responses
etisserant@223: #
etisserant@223: if port == _MDNS_PORT:
etisserant@223: self.zeroconf.handleQuery(msg, _MDNS_ADDR, _MDNS_PORT)
etisserant@223: # If it's not a multicast query, reply via unicast
etisserant@223: # and multicast
etisserant@223: #
etisserant@223: elif port == _DNS_PORT:
etisserant@223: self.zeroconf.handleQuery(msg, addr, port)
etisserant@223: self.zeroconf.handleQuery(msg, _MDNS_ADDR, _MDNS_PORT)
etisserant@223: else:
etisserant@223: self.zeroconf.handleResponse(msg)
etisserant@203:
etisserant@203:
etisserant@203: class Reaper(threading.Thread):
etisserant@223: """A Reaper is used by this module to remove cache entries that
etisserant@223: have expired."""
etisserant@223:
etisserant@223: def __init__(self, zeroconf):
etisserant@223: threading.Thread.__init__(self)
etisserant@223: self.zeroconf = zeroconf
etisserant@223: self.start()
etisserant@223:
etisserant@223: def run(self):
etisserant@223: while 1:
etisserant@223: self.zeroconf.wait(10 * 1000)
etisserant@223: if globals()['_GLOBAL_DONE']:
etisserant@223: return
etisserant@223: now = currentTimeMillis()
etisserant@223: for record in self.zeroconf.cache.entries():
etisserant@223: if record.isExpired(now):
etisserant@223: self.zeroconf.updateRecord(now, record)
etisserant@223: self.zeroconf.cache.remove(record)
etisserant@203:
etisserant@203:
etisserant@203: class ServiceBrowser(threading.Thread):
etisserant@223: """Used to browse for a service of a specific type.
etisserant@223:
etisserant@223: The listener object will have its addService() and
etisserant@223: removeService() methods called when this browser
etisserant@223: discovers changes in the services availability."""
etisserant@223:
etisserant@223: def __init__(self, zeroconf, type, listener):
etisserant@223: """Creates a browser for a specific type"""
etisserant@223: threading.Thread.__init__(self)
etisserant@223: self.zeroconf = zeroconf
etisserant@223: self.type = type
etisserant@223: self.listener = listener
etisserant@223: self.services = {}
etisserant@223: self.nextTime = currentTimeMillis()
etisserant@223: self.delay = _BROWSER_TIME
etisserant@223: self.list = []
etisserant@223:
etisserant@223: self.done = 0
etisserant@223:
etisserant@223: self.zeroconf.addListener(self, DNSQuestion(self.type, _TYPE_PTR, _CLASS_IN))
etisserant@223: self.start()
etisserant@223:
etisserant@223: def updateRecord(self, zeroconf, now, record):
etisserant@223: """Callback invoked by Zeroconf when new information arrives.
etisserant@223:
etisserant@223: Updates information required by browser in the Zeroconf cache."""
etisserant@223: if record.type == _TYPE_PTR and record.name == self.type:
etisserant@223: expired = record.isExpired(now)
etisserant@223: try:
etisserant@223: oldrecord = self.services[record.alias.lower()]
etisserant@223: if not expired:
etisserant@223: oldrecord.resetTTL(record)
etisserant@223: else:
etisserant@223: del(self.services[record.alias.lower()])
etisserant@223: callback = lambda x: self.listener.removeService(x, self.type, record.alias)
etisserant@223: self.list.append(callback)
etisserant@223: return
etisserant@223: except:
etisserant@223: if not expired:
etisserant@223: self.services[record.alias.lower()] = record
etisserant@223: callback = lambda x: self.listener.addService(x, self.type, record.alias)
etisserant@223: self.list.append(callback)
etisserant@223:
etisserant@223: expires = record.getExpirationTime(75)
etisserant@223: if expires < self.nextTime:
etisserant@223: self.nextTime = expires
etisserant@223:
etisserant@223: def cancel(self):
etisserant@223: self.done = 1
etisserant@223: self.zeroconf.notifyAll()
etisserant@223:
etisserant@223: def run(self):
etisserant@223: while 1:
etisserant@223: event = None
etisserant@223: now = currentTimeMillis()
etisserant@223: if len(self.list) == 0 and self.nextTime > now:
etisserant@223: self.zeroconf.wait(self.nextTime - now)
etisserant@223: if globals()['_GLOBAL_DONE'] or self.done:
etisserant@223: return
etisserant@223: now = currentTimeMillis()
etisserant@223:
etisserant@223: if self.nextTime <= now:
etisserant@223: out = DNSOutgoing(_FLAGS_QR_QUERY)
etisserant@223: out.addQuestion(DNSQuestion(self.type, _TYPE_PTR, _CLASS_IN))
etisserant@223: for record in self.services.values():
etisserant@223: if not record.isExpired(now):
etisserant@223: out.addAnswerAtTime(record, now)
etisserant@223: self.zeroconf.send(out)
etisserant@223: self.nextTime = now + self.delay
etisserant@223: self.delay = min(20 * 1000, self.delay * 2)
etisserant@223:
etisserant@223: if len(self.list) > 0:
etisserant@223: event = self.list.pop(0)
etisserant@223:
etisserant@223: if event is not None:
etisserant@223: event(self.zeroconf)
etisserant@223:
etisserant@203:
etisserant@203: class ServiceInfo(object):
etisserant@223: """Service information"""
etisserant@223:
etisserant@223: def __init__(self, type, name, address=None, port=None, weight=0, priority=0, properties=None, server=None):
etisserant@223: """Create a service description.
etisserant@223:
etisserant@223: type: fully qualified service type name
etisserant@223: name: fully qualified service name
etisserant@223: address: IP address as unsigned short, network byte order
etisserant@223: port: port that the service runs on
etisserant@223: weight: weight of the service
etisserant@223: priority: priority of the service
etisserant@223: properties: dictionary of properties (or a string holding the bytes for the text field)
etisserant@223: server: fully qualified name for service host (defaults to name)"""
etisserant@223:
etisserant@223: if not name.endswith(type):
etisserant@223: raise BadTypeInNameException
etisserant@223: self.type = type
etisserant@223: self.name = name
etisserant@223: self.address = address
etisserant@223: self.port = port
etisserant@223: self.weight = weight
etisserant@223: self.priority = priority
etisserant@223: if server:
etisserant@223: self.server = server
etisserant@223: else:
etisserant@223: self.server = name
etisserant@223: self.setProperties(properties)
etisserant@223:
etisserant@223: def setProperties(self, properties):
etisserant@223: """Sets properties and text of this info from a dictionary"""
etisserant@223: if isinstance(properties, dict):
etisserant@223: self.properties = properties
etisserant@223: list = []
etisserant@223: result = ''
etisserant@223: for key in properties:
etisserant@223: value = properties[key]
etisserant@223: if value is None:
etisserant@223: suffix = ''.encode('utf-8')
etisserant@223: elif isinstance(value, str):
etisserant@223: suffix = value.encode('utf-8')
etisserant@223: elif isinstance(value, int):
etisserant@223: if value:
etisserant@223: suffix = 'true'
etisserant@223: else:
etisserant@223: suffix = 'false'
etisserant@223: else:
etisserant@223: suffix = ''.encode('utf-8')
etisserant@223: list.append('='.join((key, suffix)))
etisserant@223: for item in list:
etisserant@223: result = ''.join((result, struct.pack('!c', chr(len(item))), item))
etisserant@223: self.text = result
etisserant@223: else:
etisserant@223: self.text = properties
etisserant@223:
etisserant@223: def setText(self, text):
etisserant@223: """Sets properties and text given a text field"""
etisserant@223: self.text = text
etisserant@223: try:
etisserant@223: result = {}
etisserant@223: end = len(text)
etisserant@223: index = 0
etisserant@223: strs = []
etisserant@223: while index < end:
etisserant@223: length = ord(text[index])
etisserant@223: index += 1
etisserant@223: strs.append(text[index:index+length])
etisserant@223: index += length
etisserant@223:
etisserant@223: for s in strs:
etisserant@223: eindex = s.find('=')
etisserant@223: if eindex == -1:
etisserant@223: # No equals sign at all
etisserant@223: key = s
etisserant@223: value = 0
etisserant@223: else:
etisserant@223: key = s[:eindex]
etisserant@223: value = s[eindex+1:]
etisserant@223: if value == 'true':
etisserant@223: value = 1
etisserant@223: elif value == 'false' or not value:
etisserant@223: value = 0
etisserant@223:
etisserant@223: # Only update non-existent properties
etisserant@223: if key and result.get(key) == None:
etisserant@223: result[key] = value
etisserant@223:
etisserant@223: self.properties = result
etisserant@223: except:
etisserant@223: traceback.print_exc()
etisserant@223: self.properties = None
etisserant@223:
etisserant@223: def getType(self):
etisserant@223: """Type accessor"""
etisserant@223: return self.type
etisserant@223:
etisserant@223: def getName(self):
etisserant@223: """Name accessor"""
etisserant@223: if self.type is not None and self.name.endswith("." + self.type):
etisserant@223: return self.name[:len(self.name) - len(self.type) - 1]
etisserant@223: return self.name
etisserant@223:
etisserant@223: def getAddress(self):
etisserant@223: """Address accessor"""
etisserant@223: return self.address
etisserant@223:
etisserant@223: def getPort(self):
etisserant@223: """Port accessor"""
etisserant@223: return self.port
etisserant@223:
etisserant@223: def getPriority(self):
etisserant@223: """Pirority accessor"""
etisserant@223: return self.priority
etisserant@223:
etisserant@223: def getWeight(self):
etisserant@223: """Weight accessor"""
etisserant@223: return self.weight
etisserant@223:
etisserant@223: def getProperties(self):
etisserant@223: """Properties accessor"""
etisserant@223: return self.properties
etisserant@223:
etisserant@223: def getText(self):
etisserant@223: """Text accessor"""
etisserant@223: return self.text
etisserant@223:
etisserant@223: def getServer(self):
etisserant@223: """Server accessor"""
etisserant@223: return self.server
etisserant@223:
etisserant@223: def updateRecord(self, zeroconf, now, record):
etisserant@223: """Updates service information from a DNS record"""
etisserant@223: if record is not None and not record.isExpired(now):
etisserant@223: if record.type == _TYPE_A:
b@373: if record.name == self.server:
etisserant@223: self.address = record.address
etisserant@223: elif record.type == _TYPE_SRV:
etisserant@223: if record.name == self.name:
etisserant@223: self.server = record.server
etisserant@223: self.port = record.port
etisserant@223: self.weight = record.weight
etisserant@223: self.priority = record.priority
etisserant@223: self.updateRecord(zeroconf, now, zeroconf.cache.getByDetails(self.server, _TYPE_A, _CLASS_IN))
etisserant@223: elif record.type == _TYPE_TXT:
etisserant@223: if record.name == self.name:
etisserant@223: self.setText(record.text)
etisserant@223:
etisserant@223: def request(self, zeroconf, timeout):
etisserant@223: """Returns true if the service could be discovered on the
etisserant@223: network, and updates this object with details discovered.
etisserant@223: """
etisserant@223: now = currentTimeMillis()
etisserant@223: delay = _LISTENER_TIME
etisserant@223: next = now + delay
etisserant@223: last = now + timeout
etisserant@223: result = 0
etisserant@223: try:
etisserant@223: zeroconf.addListener(self, DNSQuestion(self.name, _TYPE_ANY, _CLASS_IN))
etisserant@223: while self.server is None or self.address is None or self.text is None:
etisserant@223: if last <= now:
etisserant@223: return 0
etisserant@223: if next <= now:
etisserant@223: out = DNSOutgoing(_FLAGS_QR_QUERY)
etisserant@223: out.addQuestion(DNSQuestion(self.name, _TYPE_SRV, _CLASS_IN))
etisserant@223: out.addAnswerAtTime(zeroconf.cache.getByDetails(self.name, _TYPE_SRV, _CLASS_IN), now)
etisserant@223: out.addQuestion(DNSQuestion(self.name, _TYPE_TXT, _CLASS_IN))
etisserant@223: out.addAnswerAtTime(zeroconf.cache.getByDetails(self.name, _TYPE_TXT, _CLASS_IN), now)
etisserant@223: if self.server is not None:
etisserant@223: out.addQuestion(DNSQuestion(self.server, _TYPE_A, _CLASS_IN))
etisserant@223: out.addAnswerAtTime(zeroconf.cache.getByDetails(self.server, _TYPE_A, _CLASS_IN), now)
etisserant@223: zeroconf.send(out)
etisserant@223: next = now + delay
etisserant@223: delay = delay * 2
etisserant@223:
etisserant@223: zeroconf.wait(min(next, last) - now)
etisserant@223: now = currentTimeMillis()
etisserant@223: result = 1
etisserant@223: finally:
etisserant@223: zeroconf.removeListener(self)
etisserant@223:
etisserant@223: return result
etisserant@223:
etisserant@223: def __eq__(self, other):
etisserant@223: """Tests equality of service name"""
etisserant@223: if isinstance(other, ServiceInfo):
etisserant@223: return other.name == self.name
etisserant@223: return 0
etisserant@223:
etisserant@223: def __ne__(self, other):
etisserant@223: """Non-equality test"""
etisserant@223: return not self.__eq__(other)
etisserant@223:
etisserant@223: def __repr__(self):
etisserant@223: """String representation"""
etisserant@223: result = "service[%s,%s:%s," % (self.name, socket.inet_ntoa(self.getAddress()), self.port)
etisserant@223: if self.text is None:
etisserant@223: result += "None"
etisserant@223: else:
etisserant@223: if len(self.text) < 20:
etisserant@223: result += self.text
etisserant@223: else:
etisserant@223: result += self.text[:17] + "..."
etisserant@223: result += "]"
etisserant@223: return result
etisserant@223:
etisserant@203:
etisserant@203: class Zeroconf(object):
etisserant@223: """Implementation of Zeroconf Multicast DNS Service Discovery
etisserant@223:
etisserant@223: Supports registration, unregistration, queries and browsing.
etisserant@223: """
etisserant@223: def __init__(self, bindaddress=None):
etisserant@223: """Creates an instance of the Zeroconf class, establishing
etisserant@223: multicast communications, listening and reaping threads."""
etisserant@223: globals()['_GLOBAL_DONE'] = 0
etisserant@223: self.intf = bindaddress
etisserant@223: self.group = ('', _MDNS_PORT)
etisserant@223: self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
etisserant@223: try:
etisserant@223: self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
etisserant@223: self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
etisserant@223: except:
etisserant@223: # SO_REUSEADDR should be equivalent to SO_REUSEPORT for
etisserant@223: # multicast UDP sockets (p 731, "TCP/IP Illustrated,
etisserant@223: # Volume 2"), but some BSD-derived systems require
etisserant@223: # SO_REUSEPORT to be specified explicity. Also, not all
etisserant@223: # versions of Python have SO_REUSEPORT available. So
etisserant@223: # if you're on a BSD-based system, and haven't upgraded
etisserant@223: # to Python 2.3 yet, you may find this library doesn't
etisserant@223: # work as expected.
etisserant@223: #
etisserant@223: pass
etisserant@223: self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_TTL, 255)
etisserant@223: self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_LOOP, 1)
etisserant@223: try:
etisserant@223: self.socket.bind(self.group)
etisserant@223: except:
etisserant@223: # Some versions of linux raise an exception even though
etisserant@223: # the SO_REUSE* options have been set, so ignore it
etisserant@223: #
etisserant@223: pass
etisserant@223:
etisserant@223: if self.intf is not None:
etisserant@223: self.socket.setsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(self.intf) + socket.inet_aton('0.0.0.0'))
etisserant@223: self.socket.setsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(_MDNS_ADDR) + socket.inet_aton('0.0.0.0'))
etisserant@223:
etisserant@223: self.listeners = []
etisserant@223: self.browsers = []
etisserant@223: self.services = {}
etisserant@223:
etisserant@223: self.cache = DNSCache()
etisserant@223:
etisserant@223: self.condition = threading.Condition()
etisserant@223:
etisserant@223: self.engine = Engine(self)
etisserant@223: self.listener = Listener(self)
etisserant@223: self.reaper = Reaper(self)
etisserant@223:
etisserant@223: def isLoopback(self):
etisserant@223: if self.intf is not None:
etisserant@223: return self.intf.startswith("127.0.0.1")
etisserant@223: return False
etisserant@223:
etisserant@223: def isLinklocal(self):
etisserant@223: if self.intf is not None:
etisserant@223: return self.intf.startswith("169.254.")
etisserant@223: return False
etisserant@223:
etisserant@223: def wait(self, timeout):
etisserant@223: """Calling thread waits for a given number of milliseconds or
etisserant@223: until notified."""
etisserant@223: self.condition.acquire()
etisserant@223: self.condition.wait(timeout/1000)
etisserant@223: self.condition.release()
etisserant@223:
etisserant@223: def notifyAll(self):
etisserant@223: """Notifies all waiting threads"""
etisserant@223: self.condition.acquire()
etisserant@223: self.condition.notifyAll()
etisserant@223: self.condition.release()
etisserant@223:
etisserant@223: def getServiceInfo(self, type, name, timeout=3000):
etisserant@223: """Returns network's service information for a particular
etisserant@223: name and type, or None if no service matches by the timeout,
etisserant@223: which defaults to 3 seconds."""
etisserant@223: info = ServiceInfo(type, name)
etisserant@223: if info.request(self, timeout):
etisserant@223: return info
etisserant@223: return None
etisserant@223:
etisserant@223: def addServiceListener(self, type, listener):
etisserant@223: """Adds a listener for a particular service type. This object
etisserant@223: will then have its updateRecord method called when information
etisserant@223: arrives for that type."""
etisserant@223: self.removeServiceListener(listener)
etisserant@223: self.browsers.append(ServiceBrowser(self, type, listener))
etisserant@223:
etisserant@223: def removeServiceListener(self, listener):
etisserant@223: """Removes a listener from the set that is currently listening."""
etisserant@223: for browser in self.browsers:
etisserant@223: if browser.listener == listener:
etisserant@223: browser.cancel()
etisserant@223: del(browser)
etisserant@223:
etisserant@223: def registerService(self, info, ttl=_DNS_TTL):
etisserant@223: """Registers service information to the network with a default TTL
etisserant@223: of 60 seconds. Zeroconf will then respond to requests for
etisserant@223: information for that service. The name of the service may be
etisserant@223: changed if needed to make it unique on the network."""
etisserant@223: self.checkService(info)
etisserant@223: self.services[info.name.lower()] = info
etisserant@223: now = currentTimeMillis()
etisserant@223: nextTime = now
etisserant@223: i = 0
etisserant@223: while i < 3:
etisserant@223: if now < nextTime:
etisserant@223: self.wait(nextTime - now)
etisserant@223: now = currentTimeMillis()
etisserant@223: continue
etisserant@223: out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
etisserant@223: out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, ttl, info.name), 0)
etisserant@223: out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, ttl, info.priority, info.weight, info.port, info.server), 0)
etisserant@223: out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, ttl, info.text), 0)
etisserant@223: if info.address:
etisserant@223: out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, ttl, info.address), 0)
etisserant@223: self.send(out)
etisserant@223: i += 1
etisserant@223: nextTime += _REGISTER_TIME
etisserant@223:
etisserant@223: def unregisterService(self, info):
etisserant@223: """Unregister a service."""
etisserant@223: try:
etisserant@223: del(self.services[info.name.lower()])
etisserant@223: except:
etisserant@223: pass
etisserant@223: now = currentTimeMillis()
etisserant@223: nextTime = now
etisserant@223: i = 0
etisserant@223: while i < 3:
etisserant@223: if now < nextTime:
etisserant@223: self.wait(nextTime - now)
etisserant@223: now = currentTimeMillis()
etisserant@223: continue
etisserant@223: out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
etisserant@223: out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, 0, info.name), 0)
etisserant@223: out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, 0, info.priority, info.weight, info.port, info.name), 0)
etisserant@223: out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, 0, info.text), 0)
etisserant@223: if info.address:
etisserant@223: out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, 0, info.address), 0)
etisserant@223: self.send(out)
etisserant@223: i += 1
etisserant@223: nextTime += _UNREGISTER_TIME
etisserant@223:
etisserant@223: def unregisterAllServices(self):
etisserant@223: """Unregister all registered services."""
etisserant@223: if len(self.services) > 0:
etisserant@223: now = currentTimeMillis()
etisserant@223: nextTime = now
etisserant@223: i = 0
etisserant@223: while i < 3:
etisserant@223: if now < nextTime:
etisserant@223: self.wait(nextTime - now)
etisserant@223: now = currentTimeMillis()
etisserant@223: continue
etisserant@223: out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
etisserant@223: for info in self.services.values():
etisserant@223: out.addAnswerAtTime(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, 0, info.name), 0)
etisserant@223: out.addAnswerAtTime(DNSService(info.name, _TYPE_SRV, _CLASS_IN, 0, info.priority, info.weight, info.port, info.server), 0)
etisserant@223: out.addAnswerAtTime(DNSText(info.name, _TYPE_TXT, _CLASS_IN, 0, info.text), 0)
etisserant@223: if info.address:
etisserant@223: out.addAnswerAtTime(DNSAddress(info.server, _TYPE_A, _CLASS_IN, 0, info.address), 0)
etisserant@223: self.send(out)
etisserant@223: i += 1
etisserant@223: nextTime += _UNREGISTER_TIME
etisserant@223:
etisserant@223: def checkService(self, info):
etisserant@223: """Checks the network for a unique service name, modifying the
etisserant@223: ServiceInfo passed in if it is not unique."""
etisserant@223: now = currentTimeMillis()
etisserant@223: nextTime = now
etisserant@223: i = 0
etisserant@223: while i < 3:
etisserant@223: for record in self.cache.entriesWithName(info.type):
etisserant@223: if record.type == _TYPE_PTR and not record.isExpired(now) and record.alias == info.name:
etisserant@223: if (info.name.find('.') < 0):
etisserant@223: info.name = info.name + ".[" + info.address + ":" + info.port + "]." + info.type
etisserant@223: self.checkService(info)
etisserant@223: return
etisserant@223: raise NonUniqueNameException
etisserant@223: if now < nextTime:
etisserant@223: self.wait(nextTime - now)
etisserant@223: now = currentTimeMillis()
etisserant@223: continue
etisserant@223: out = DNSOutgoing(_FLAGS_QR_QUERY | _FLAGS_AA)
etisserant@223: self.debug = out
etisserant@223: out.addQuestion(DNSQuestion(info.type, _TYPE_PTR, _CLASS_IN))
etisserant@223: out.addAuthorativeAnswer(DNSPointer(info.type, _TYPE_PTR, _CLASS_IN, _DNS_TTL, info.name))
etisserant@223: self.send(out)
etisserant@223: i += 1
etisserant@223: nextTime += _CHECK_TIME
etisserant@223:
etisserant@223: def addListener(self, listener, question):
etisserant@223: """Adds a listener for a given question. The listener will have
etisserant@223: its updateRecord method called when information is available to
etisserant@223: answer the question."""
etisserant@223: now = currentTimeMillis()
etisserant@223: self.listeners.append(listener)
etisserant@223: if question is not None:
etisserant@223: for record in self.cache.entriesWithName(question.name):
etisserant@223: if question.answeredBy(record) and not record.isExpired(now):
etisserant@223: listener.updateRecord(self, now, record)
etisserant@223: self.notifyAll()
etisserant@223:
etisserant@223: def removeListener(self, listener):
etisserant@223: """Removes a listener."""
etisserant@223: try:
etisserant@223: self.listeners.remove(listener)
etisserant@223: self.notifyAll()
etisserant@223: except:
etisserant@223: pass
etisserant@223:
etisserant@223: def updateRecord(self, now, rec):
etisserant@223: """Used to notify listeners of new information that has updated
etisserant@223: a record."""
etisserant@223: for listener in self.listeners:
etisserant@223: listener.updateRecord(self, now, rec)
etisserant@223: self.notifyAll()
etisserant@223:
etisserant@223: def handleResponse(self, msg):
etisserant@223: """Deal with incoming response packets. All answers
etisserant@223: are held in the cache, and listeners are notified."""
etisserant@223: now = currentTimeMillis()
etisserant@223: for record in msg.answers:
etisserant@223: expired = record.isExpired(now)
etisserant@223: if record in self.cache.entries():
etisserant@223: if expired:
etisserant@223: self.cache.remove(record)
etisserant@223: else:
etisserant@223: entry = self.cache.get(record)
etisserant@223: if entry is not None:
etisserant@223: entry.resetTTL(record)
etisserant@223: record = entry
etisserant@223: else:
etisserant@223: self.cache.add(record)
etisserant@223:
etisserant@223: self.updateRecord(now, record)
etisserant@223:
etisserant@223: def handleQuery(self, msg, addr, port):
etisserant@223: """Deal with incoming query packets. Provides a response if
etisserant@223: possible."""
etisserant@223: out = None
etisserant@223:
etisserant@223: # Support unicast client responses
etisserant@223: #
etisserant@223: if port != _MDNS_PORT:
etisserant@223: out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA, 0)
etisserant@223: for question in msg.questions:
etisserant@223: out.addQuestion(question)
etisserant@223:
etisserant@223: for question in msg.questions:
etisserant@223: if question.type == _TYPE_PTR:
etisserant@223: for service in self.services.values():
etisserant@223: if question.name == service.type:
etisserant@223: if out is None:
etisserant@223: out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
etisserant@223: out.addAnswer(msg, DNSPointer(service.type, _TYPE_PTR, _CLASS_IN, _DNS_TTL, service.name))
etisserant@223: else:
etisserant@223: try:
etisserant@223: if out is None:
etisserant@223: out = DNSOutgoing(_FLAGS_QR_RESPONSE | _FLAGS_AA)
etisserant@223:
etisserant@223: # Answer A record queries for any service addresses we know
etisserant@223: if question.type == _TYPE_A or question.type == _TYPE_ANY:
etisserant@223: for service in self.services.values():
etisserant@223: if service.server == question.name.lower():
etisserant@223: out.addAnswer(msg, DNSAddress(question.name, _TYPE_A, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.address))
etisserant@223:
etisserant@223: service = self.services.get(question.name.lower(), None)
etisserant@223: if not service: continue
etisserant@223:
etisserant@223: if question.type == _TYPE_SRV or question.type == _TYPE_ANY:
etisserant@223: out.addAnswer(msg, DNSService(question.name, _TYPE_SRV, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.priority, service.weight, service.port, service.server))
etisserant@223: if question.type == _TYPE_TXT or question.type == _TYPE_ANY:
etisserant@223: out.addAnswer(msg, DNSText(question.name, _TYPE_TXT, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.text))
etisserant@223: if question.type == _TYPE_SRV:
etisserant@223: out.addAdditionalAnswer(DNSAddress(service.server, _TYPE_A, _CLASS_IN | _CLASS_UNIQUE, _DNS_TTL, service.address))
etisserant@223: except:
etisserant@223: traceback.print_exc()
etisserant@223:
etisserant@223: if out is not None and out.answers:
etisserant@223: out.id = msg.id
etisserant@223: self.send(out, addr, port)
etisserant@223:
etisserant@223: def send(self, out, addr = _MDNS_ADDR, port = _MDNS_PORT):
etisserant@223: """Sends an outgoing packet."""
etisserant@223: # This is a quick test to see if we can parse the packets we generate
etisserant@223: #temp = DNSIncoming(out.packet())
etisserant@223: try:
etisserant@223: bytes_sent = self.socket.sendto(out.packet(), 0, (addr, port))
etisserant@223: except:
etisserant@223: # Ignore this, it may be a temporary loss of network connection
etisserant@223: pass
etisserant@223:
etisserant@223: def close(self):
etisserant@223: """Ends the background threads, and prevent this instance from
etisserant@223: servicing further queries."""
etisserant@223: if globals()['_GLOBAL_DONE'] == 0:
etisserant@223: globals()['_GLOBAL_DONE'] = 1
etisserant@223: self.notifyAll()
etisserant@223: self.engine.notify()
etisserant@223: self.unregisterAllServices()
etisserant@223: self.socket.setsockopt(socket.SOL_IP, socket.IP_DROP_MEMBERSHIP, socket.inet_aton(_MDNS_ADDR) + socket.inet_aton('0.0.0.0'))
etisserant@223: self.socket.close()
etisserant@223:
etisserant@203: # Test a few module features, including service registration, service
etisserant@203: # query (for Zoe), and service unregistration.
etisserant@203:
etisserant@223: if __name__ == '__main__':
etisserant@223: print "Multicast DNS Service Discovery for Python, version", __version__
etisserant@223: r = Zeroconf()
etisserant@223: print "1. Testing registration of a service..."
etisserant@223: desc = {'version':'0.10','a':'test value', 'b':'another value'}
etisserant@223: info = ServiceInfo("_http._tcp.local.", "My Service Name._http._tcp.local.", socket.inet_aton("127.0.0.1"), 1234, 0, 0, desc)
etisserant@223: print " Registering service..."
etisserant@223: r.registerService(info)
etisserant@223: print " Registration done."
etisserant@223: print "2. Testing query of service information..."
etisserant@223: print " Getting ZOE service:", str(r.getServiceInfo("_http._tcp.local.", "ZOE._http._tcp.local."))
etisserant@223: print " Query done."
etisserant@223: print "3. Testing query of own service..."
etisserant@223: print " Getting self:", str(r.getServiceInfo("_http._tcp.local.", "My Service Name._http._tcp.local."))
etisserant@223: print " Query done."
etisserant@223: print "4. Testing unregister of service information..."
etisserant@223: r.unregisterService(info)
etisserant@223: print " Unregister done."
etisserant@223: r.close()