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Diffstat (limited to 'third_party/dnspython/dns/message.py')
| -rw-r--r-- | third_party/dnspython/dns/message.py | 1088 |
1 files changed, 0 insertions, 1088 deletions
diff --git a/third_party/dnspython/dns/message.py b/third_party/dnspython/dns/message.py deleted file mode 100644 index cf291339347..00000000000 --- a/third_party/dnspython/dns/message.py +++ /dev/null @@ -1,1088 +0,0 @@ -# Copyright (C) 2001-2007, 2009-2011 Nominum, Inc. -# -# Permission to use, copy, modify, and distribute this software and its -# documentation for any purpose with or without fee is hereby granted, -# provided that the above copyright notice and this permission notice -# appear in all copies. -# -# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES -# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF -# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR -# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES -# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN -# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT -# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. - -"""DNS Messages""" - -import cStringIO -import random -import struct -import sys -import time - -import dns.edns -import dns.exception -import dns.flags -import dns.name -import dns.opcode -import dns.entropy -import dns.rcode -import dns.rdata -import dns.rdataclass -import dns.rdatatype -import dns.rrset -import dns.renderer -import dns.tsig -import dns.wiredata - -class ShortHeader(dns.exception.FormError): - """Raised if the DNS packet passed to from_wire() is too short.""" - pass - -class TrailingJunk(dns.exception.FormError): - """Raised if the DNS packet passed to from_wire() has extra junk - at the end of it.""" - pass - -class UnknownHeaderField(dns.exception.DNSException): - """Raised if a header field name is not recognized when converting from - text into a message.""" - pass - -class BadEDNS(dns.exception.FormError): - """Raised if an OPT record occurs somewhere other than the start of - the additional data section.""" - pass - -class BadTSIG(dns.exception.FormError): - """Raised if a TSIG record occurs somewhere other than the end of - the additional data section.""" - pass - -class UnknownTSIGKey(dns.exception.DNSException): - """Raised if we got a TSIG but don't know the key.""" - pass - -class Message(object): - """A DNS message. - - @ivar id: The query id; the default is a randomly chosen id. - @type id: int - @ivar flags: The DNS flags of the message. @see: RFC 1035 for an - explanation of these flags. - @type flags: int - @ivar question: The question section. - @type question: list of dns.rrset.RRset objects - @ivar answer: The answer section. - @type answer: list of dns.rrset.RRset objects - @ivar authority: The authority section. - @type authority: list of dns.rrset.RRset objects - @ivar additional: The additional data section. - @type additional: list of dns.rrset.RRset objects - @ivar edns: The EDNS level to use. The default is -1, no Edns. - @type edns: int - @ivar ednsflags: The EDNS flags - @type ednsflags: long - @ivar payload: The EDNS payload size. The default is 0. - @type payload: int - @ivar options: The EDNS options - @type options: list of dns.edns.Option objects - @ivar request_payload: The associated request's EDNS payload size. - @type request_payload: int - @ivar keyring: The TSIG keyring to use. The default is None. - @type keyring: dict - @ivar keyname: The TSIG keyname to use. The default is None. - @type keyname: dns.name.Name object - @ivar keyalgorithm: The TSIG algorithm to use; defaults to - dns.tsig.default_algorithm. Constants for TSIG algorithms are defined - in dns.tsig, and the currently implemented algorithms are - HMAC_MD5, HMAC_SHA1, HMAC_SHA224, HMAC_SHA256, HMAC_SHA384, and - HMAC_SHA512. - @type keyalgorithm: string - @ivar request_mac: The TSIG MAC of the request message associated with - this message; used when validating TSIG signatures. @see: RFC 2845 for - more information on TSIG fields. - @type request_mac: string - @ivar fudge: TSIG time fudge; default is 300 seconds. - @type fudge: int - @ivar original_id: TSIG original id; defaults to the message's id - @type original_id: int - @ivar tsig_error: TSIG error code; default is 0. - @type tsig_error: int - @ivar other_data: TSIG other data. - @type other_data: string - @ivar mac: The TSIG MAC for this message. - @type mac: string - @ivar xfr: Is the message being used to contain the results of a DNS - zone transfer? The default is False. - @type xfr: bool - @ivar origin: The origin of the zone in messages which are used for - zone transfers or for DNS dynamic updates. The default is None. - @type origin: dns.name.Name object - @ivar tsig_ctx: The TSIG signature context associated with this - message. The default is None. - @type tsig_ctx: hmac.HMAC object - @ivar had_tsig: Did the message decoded from wire format have a TSIG - signature? - @type had_tsig: bool - @ivar multi: Is this message part of a multi-message sequence? The - default is false. This variable is used when validating TSIG signatures - on messages which are part of a zone transfer. - @type multi: bool - @ivar first: Is this message standalone, or the first of a multi - message sequence? This variable is used when validating TSIG signatures - on messages which are part of a zone transfer. - @type first: bool - @ivar index: An index of rrsets in the message. The index key is - (section, name, rdclass, rdtype, covers, deleting). Indexing can be - disabled by setting the index to None. - @type index: dict - """ - - def __init__(self, id=None): - if id is None: - self.id = dns.entropy.random_16() - else: - self.id = id - self.flags = 0 - self.question = [] - self.answer = [] - self.authority = [] - self.additional = [] - self.edns = -1 - self.ednsflags = 0 - self.payload = 0 - self.options = [] - self.request_payload = 0 - self.keyring = None - self.keyname = None - self.keyalgorithm = dns.tsig.default_algorithm - self.request_mac = '' - self.other_data = '' - self.tsig_error = 0 - self.fudge = 300 - self.original_id = self.id - self.mac = '' - self.xfr = False - self.origin = None - self.tsig_ctx = None - self.had_tsig = False - self.multi = False - self.first = True - self.index = {} - - def __repr__(self): - return '<DNS message, ID ' + `self.id` + '>' - - def __str__(self): - return self.to_text() - - def to_text(self, origin=None, relativize=True, **kw): - """Convert the message to text. - - The I{origin}, I{relativize}, and any other keyword - arguments are passed to the rrset to_wire() method. - - @rtype: string - """ - - s = cStringIO.StringIO() - print >> s, 'id %d' % self.id - print >> s, 'opcode %s' % \ - dns.opcode.to_text(dns.opcode.from_flags(self.flags)) - rc = dns.rcode.from_flags(self.flags, self.ednsflags) - print >> s, 'rcode %s' % dns.rcode.to_text(rc) - print >> s, 'flags %s' % dns.flags.to_text(self.flags) - if self.edns >= 0: - print >> s, 'edns %s' % self.edns - if self.ednsflags != 0: - print >> s, 'eflags %s' % \ - dns.flags.edns_to_text(self.ednsflags) - print >> s, 'payload', self.payload - is_update = dns.opcode.is_update(self.flags) - if is_update: - print >> s, ';ZONE' - else: - print >> s, ';QUESTION' - for rrset in self.question: - print >> s, rrset.to_text(origin, relativize, **kw) - if is_update: - print >> s, ';PREREQ' - else: - print >> s, ';ANSWER' - for rrset in self.answer: - print >> s, rrset.to_text(origin, relativize, **kw) - if is_update: - print >> s, ';UPDATE' - else: - print >> s, ';AUTHORITY' - for rrset in self.authority: - print >> s, rrset.to_text(origin, relativize, **kw) - print >> s, ';ADDITIONAL' - for rrset in self.additional: - print >> s, rrset.to_text(origin, relativize, **kw) - # - # We strip off the final \n so the caller can print the result without - # doing weird things to get around eccentricities in Python print - # formatting - # - return s.getvalue()[:-1] - - def __eq__(self, other): - """Two messages are equal if they have the same content in the - header, question, answer, and authority sections. - @rtype: bool""" - if not isinstance(other, Message): - return False - if self.id != other.id: - return False - if self.flags != other.flags: - return False - for n in self.question: - if n not in other.question: - return False - for n in other.question: - if n not in self.question: - return False - for n in self.answer: - if n not in other.answer: - return False - for n in other.answer: - if n not in self.answer: - return False - for n in self.authority: - if n not in other.authority: - return False - for n in other.authority: - if n not in self.authority: - return False - return True - - def __ne__(self, other): - """Are two messages not equal? - @rtype: bool""" - return not self.__eq__(other) - - def is_response(self, other): - """Is other a response to self? - @rtype: bool""" - if other.flags & dns.flags.QR == 0 or \ - self.id != other.id or \ - dns.opcode.from_flags(self.flags) != \ - dns.opcode.from_flags(other.flags): - return False - if dns.rcode.from_flags(other.flags, other.ednsflags) != \ - dns.rcode.NOERROR: - return True - if dns.opcode.is_update(self.flags): - return True - for n in self.question: - if n not in other.question: - return False - for n in other.question: - if n not in self.question: - return False - return True - - def section_number(self, section): - if section is self.question: - return 0 - elif section is self.answer: - return 1 - elif section is self.authority: - return 2 - elif section is self.additional: - return 3 - else: - raise ValueError('unknown section') - - def find_rrset(self, section, name, rdclass, rdtype, - covers=dns.rdatatype.NONE, deleting=None, create=False, - force_unique=False): - """Find the RRset with the given attributes in the specified section. - - @param section: the section of the message to look in, e.g. - self.answer. - @type section: list of dns.rrset.RRset objects - @param name: the name of the RRset - @type name: dns.name.Name object - @param rdclass: the class of the RRset - @type rdclass: int - @param rdtype: the type of the RRset - @type rdtype: int - @param covers: the covers value of the RRset - @type covers: int - @param deleting: the deleting value of the RRset - @type deleting: int - @param create: If True, create the RRset if it is not found. - The created RRset is appended to I{section}. - @type create: bool - @param force_unique: If True and create is also True, create a - new RRset regardless of whether a matching RRset exists already. - @type force_unique: bool - @raises KeyError: the RRset was not found and create was False - @rtype: dns.rrset.RRset object""" - - key = (self.section_number(section), - name, rdclass, rdtype, covers, deleting) - if not force_unique: - if not self.index is None: - rrset = self.index.get(key) - if not rrset is None: - return rrset - else: - for rrset in section: - if rrset.match(name, rdclass, rdtype, covers, deleting): - return rrset - if not create: - raise KeyError - rrset = dns.rrset.RRset(name, rdclass, rdtype, covers, deleting) - section.append(rrset) - if not self.index is None: - self.index[key] = rrset - return rrset - - def get_rrset(self, section, name, rdclass, rdtype, - covers=dns.rdatatype.NONE, deleting=None, create=False, - force_unique=False): - """Get the RRset with the given attributes in the specified section. - - If the RRset is not found, None is returned. - - @param section: the section of the message to look in, e.g. - self.answer. - @type section: list of dns.rrset.RRset objects - @param name: the name of the RRset - @type name: dns.name.Name object - @param rdclass: the class of the RRset - @type rdclass: int - @param rdtype: the type of the RRset - @type rdtype: int - @param covers: the covers value of the RRset - @type covers: int - @param deleting: the deleting value of the RRset - @type deleting: int - @param create: If True, create the RRset if it is not found. - The created RRset is appended to I{section}. - @type create: bool - @param force_unique: If True and create is also True, create a - new RRset regardless of whether a matching RRset exists already. - @type force_unique: bool - @rtype: dns.rrset.RRset object or None""" - - try: - rrset = self.find_rrset(section, name, rdclass, rdtype, covers, - deleting, create, force_unique) - except KeyError: - rrset = None - return rrset - - def to_wire(self, origin=None, max_size=0, **kw): - """Return a string containing the message in DNS compressed wire - format. - - Additional keyword arguments are passed to the rrset to_wire() - method. - - @param origin: The origin to be appended to any relative names. - @type origin: dns.name.Name object - @param max_size: The maximum size of the wire format output; default - is 0, which means 'the message's request payload, if nonzero, or - 65536'. - @type max_size: int - @raises dns.exception.TooBig: max_size was exceeded - @rtype: string - """ - - if max_size == 0: - if self.request_payload != 0: - max_size = self.request_payload - else: - max_size = 65535 - if max_size < 512: - max_size = 512 - elif max_size > 65535: - max_size = 65535 - r = dns.renderer.Renderer(self.id, self.flags, max_size, origin) - for rrset in self.question: - r.add_question(rrset.name, rrset.rdtype, rrset.rdclass) - for rrset in self.answer: - r.add_rrset(dns.renderer.ANSWER, rrset, **kw) - for rrset in self.authority: - r.add_rrset(dns.renderer.AUTHORITY, rrset, **kw) - if self.edns >= 0: - r.add_edns(self.edns, self.ednsflags, self.payload, self.options) - for rrset in self.additional: - r.add_rrset(dns.renderer.ADDITIONAL, rrset, **kw) - r.write_header() - if not self.keyname is None: - r.add_tsig(self.keyname, self.keyring[self.keyname], - self.fudge, self.original_id, self.tsig_error, - self.other_data, self.request_mac, - self.keyalgorithm) - self.mac = r.mac - return r.get_wire() - - def use_tsig(self, keyring, keyname=None, fudge=300, - original_id=None, tsig_error=0, other_data='', - algorithm=dns.tsig.default_algorithm): - """When sending, a TSIG signature using the specified keyring - and keyname should be added. - - @param keyring: The TSIG keyring to use; defaults to None. - @type keyring: dict - @param keyname: The name of the TSIG key to use; defaults to None. - The key must be defined in the keyring. If a keyring is specified - but a keyname is not, then the key used will be the first key in the - keyring. Note that the order of keys in a dictionary is not defined, - so applications should supply a keyname when a keyring is used, unless - they know the keyring contains only one key. - @type keyname: dns.name.Name or string - @param fudge: TSIG time fudge; default is 300 seconds. - @type fudge: int - @param original_id: TSIG original id; defaults to the message's id - @type original_id: int - @param tsig_error: TSIG error code; default is 0. - @type tsig_error: int - @param other_data: TSIG other data. - @type other_data: string - @param algorithm: The TSIG algorithm to use; defaults to - dns.tsig.default_algorithm - """ - - self.keyring = keyring - if keyname is None: - self.keyname = self.keyring.keys()[0] - else: - if isinstance(keyname, (str, unicode)): - keyname = dns.name.from_text(keyname) - self.keyname = keyname - self.keyalgorithm = algorithm - self.fudge = fudge - if original_id is None: - self.original_id = self.id - else: - self.original_id = original_id - self.tsig_error = tsig_error - self.other_data = other_data - - def use_edns(self, edns=0, ednsflags=0, payload=1280, request_payload=None, options=None): - """Configure EDNS behavior. - @param edns: The EDNS level to use. Specifying None, False, or -1 - means 'do not use EDNS', and in this case the other parameters are - ignored. Specifying True is equivalent to specifying 0, i.e. 'use - EDNS0'. - @type edns: int or bool or None - @param ednsflags: EDNS flag values. - @type ednsflags: int - @param payload: The EDNS sender's payload field, which is the maximum - size of UDP datagram the sender can handle. - @type payload: int - @param request_payload: The EDNS payload size to use when sending - this message. If not specified, defaults to the value of payload. - @type request_payload: int or None - @param options: The EDNS options - @type options: None or list of dns.edns.Option objects - @see: RFC 2671 - """ - if edns is None or edns is False: - edns = -1 - if edns is True: - edns = 0 - if request_payload is None: - request_payload = payload - if edns < 0: - ednsflags = 0 - payload = 0 - request_payload = 0 - options = [] - else: - # make sure the EDNS version in ednsflags agrees with edns - ednsflags &= 0xFF00FFFFL - ednsflags |= (edns << 16) - if options is None: - options = [] - self.edns = edns - self.ednsflags = ednsflags - self.payload = payload - self.options = options - self.request_payload = request_payload - - def want_dnssec(self, wanted=True): - """Enable or disable 'DNSSEC desired' flag in requests. - @param wanted: Is DNSSEC desired? If True, EDNS is enabled if - required, and then the DO bit is set. If False, the DO bit is - cleared if EDNS is enabled. - @type wanted: bool - """ - if wanted: - if self.edns < 0: - self.use_edns() - self.ednsflags |= dns.flags.DO - elif self.edns >= 0: - self.ednsflags &= ~dns.flags.DO - - def rcode(self): - """Return the rcode. - @rtype: int - """ - return dns.rcode.from_flags(self.flags, self.ednsflags) - - def set_rcode(self, rcode): - """Set the rcode. - @param rcode: the rcode - @type rcode: int - """ - (value, evalue) = dns.rcode.to_flags(rcode) - self.flags &= 0xFFF0 - self.flags |= value - self.ednsflags &= 0x00FFFFFFL - self.ednsflags |= evalue - if self.ednsflags != 0 and self.edns < 0: - self.edns = 0 - - def opcode(self): - """Return the opcode. - @rtype: int - """ - return dns.opcode.from_flags(self.flags) - - def set_opcode(self, opcode): - """Set the opcode. - @param opcode: the opcode - @type opcode: int - """ - self.flags &= 0x87FF - self.flags |= dns.opcode.to_flags(opcode) - -class _WireReader(object): - """Wire format reader. - - @ivar wire: the wire-format message. - @type wire: string - @ivar message: The message object being built - @type message: dns.message.Message object - @ivar current: When building a message object from wire format, this - variable contains the offset from the beginning of wire of the next octet - to be read. - @type current: int - @ivar updating: Is the message a dynamic update? - @type updating: bool - @ivar one_rr_per_rrset: Put each RR into its own RRset? - @type one_rr_per_rrset: bool - @ivar zone_rdclass: The class of the zone in messages which are - DNS dynamic updates. - @type zone_rdclass: int - """ - - def __init__(self, wire, message, question_only=False, - one_rr_per_rrset=False): - self.wire = dns.wiredata.maybe_wrap(wire) - self.message = message - self.current = 0 - self.updating = False - self.zone_rdclass = dns.rdataclass.IN - self.question_only = question_only - self.one_rr_per_rrset = one_rr_per_rrset - - def _get_question(self, qcount): - """Read the next I{qcount} records from the wire data and add them to - the question section. - @param qcount: the number of questions in the message - @type qcount: int""" - - if self.updating and qcount > 1: - raise dns.exception.FormError - - for i in xrange(0, qcount): - (qname, used) = dns.name.from_wire(self.wire, self.current) - if not self.message.origin is None: - qname = qname.relativize(self.message.origin) - self.current = self.current + used - (rdtype, rdclass) = \ - struct.unpack('!HH', - self.wire[self.current:self.current + 4]) - self.current = self.current + 4 - self.message.find_rrset(self.message.question, qname, - rdclass, rdtype, create=True, - force_unique=True) - if self.updating: - self.zone_rdclass = rdclass - - def _get_section(self, section, count): - """Read the next I{count} records from the wire data and add them to - the specified section. - @param section: the section of the message to which to add records - @type section: list of dns.rrset.RRset objects - @param count: the number of records to read - @type count: int""" - - if self.updating or self.one_rr_per_rrset: - force_unique = True - else: - force_unique = False - seen_opt = False - for i in xrange(0, count): - rr_start = self.current - (name, used) = dns.name.from_wire(self.wire, self.current) - absolute_name = name - if not self.message.origin is None: - name = name.relativize(self.message.origin) - self.current = self.current + used - (rdtype, rdclass, ttl, rdlen) = \ - struct.unpack('!HHIH', - self.wire[self.current:self.current + 10]) - self.current = self.current + 10 - if rdtype == dns.rdatatype.OPT: - if not section is self.message.additional or seen_opt: - raise BadEDNS - self.message.payload = rdclass - self.message.ednsflags = ttl - self.message.edns = (ttl & 0xff0000) >> 16 - self.message.options = [] - current = self.current - optslen = rdlen - while optslen > 0: - (otype, olen) = \ - struct.unpack('!HH', - self.wire[current:current + 4]) - current = current + 4 - opt = dns.edns.option_from_wire(otype, self.wire, current, olen) - self.message.options.append(opt) - current = current + olen - optslen = optslen - 4 - olen - seen_opt = True - elif rdtype == dns.rdatatype.TSIG: - if not (section is self.message.additional and - i == (count - 1)): - raise BadTSIG - if self.message.keyring is None: - raise UnknownTSIGKey('got signed message without keyring') - secret = self.message.keyring.get(absolute_name) - if secret is None: - raise UnknownTSIGKey("key '%s' unknown" % name) - self.message.tsig_ctx = \ - dns.tsig.validate(self.wire, - absolute_name, - secret, - int(time.time()), - self.message.request_mac, - rr_start, - self.current, - rdlen, - self.message.tsig_ctx, - self.message.multi, - self.message.first) - self.message.had_tsig = True - else: - if ttl < 0: - ttl = 0 - if self.updating and \ - (rdclass == dns.rdataclass.ANY or - rdclass == dns.rdataclass.NONE): - deleting = rdclass - rdclass = self.zone_rdclass - else: - deleting = None - if deleting == dns.rdataclass.ANY or \ - (deleting == dns.rdataclass.NONE and \ - section is self.message.answer): - covers = dns.rdatatype.NONE - rd = None - else: - rd = dns.rdata.from_wire(rdclass, rdtype, self.wire, - self.current, rdlen, - self.message.origin) - covers = rd.covers() - if self.message.xfr and rdtype == dns.rdatatype.SOA: - force_unique = True - rrset = self.message.find_rrset(section, name, - rdclass, rdtype, covers, - deleting, True, force_unique) - if not rd is None: - rrset.add(rd, ttl) - self.current = self.current + rdlen - - def read(self): - """Read a wire format DNS message and build a dns.message.Message - object.""" - - l = len(self.wire) - if l < 12: - raise ShortHeader - (self.message.id, self.message.flags, qcount, ancount, - aucount, adcount) = struct.unpack('!HHHHHH', self.wire[:12]) - self.current = 12 - if dns.opcode.is_update(self.message.flags): - self.updating = True - self._get_question(qcount) - if self.question_only: - return - self._get_section(self.message.answer, ancount) - self._get_section(self.message.authority, aucount) - self._get_section(self.message.additional, adcount) - if self.current != l: - raise TrailingJunk - if self.message.multi and self.message.tsig_ctx and \ - not self.message.had_tsig: - self.message.tsig_ctx.update(self.wire) - - -def from_wire(wire, keyring=None, request_mac='', xfr=False, origin=None, - tsig_ctx = None, multi = False, first = True, - question_only = False, one_rr_per_rrset = False): - """Convert a DNS wire format message into a message - object. - - @param keyring: The keyring to use if the message is signed. - @type keyring: dict - @param request_mac: If the message is a response to a TSIG-signed request, - I{request_mac} should be set to the MAC of that request. - @type request_mac: string - @param xfr: Is this message part of a zone transfer? - @type xfr: bool - @param origin: If the message is part of a zone transfer, I{origin} - should be the origin name of the zone. - @type origin: dns.name.Name object - @param tsig_ctx: The ongoing TSIG context, used when validating zone - transfers. - @type tsig_ctx: hmac.HMAC object - @param multi: Is this message part of a multiple message sequence? - @type multi: bool - @param first: Is this message standalone, or the first of a multi - message sequence? - @type first: bool - @param question_only: Read only up to the end of the question section? - @type question_only: bool - @param one_rr_per_rrset: Put each RR into its own RRset - @type one_rr_per_rrset: bool - @raises ShortHeader: The message is less than 12 octets long. - @raises TrailingJunk: There were octets in the message past the end - of the proper DNS message. - @raises BadEDNS: An OPT record was in the wrong section, or occurred more - than once. - @raises BadTSIG: A TSIG record was not the last record of the additional - data section. - @rtype: dns.message.Message object""" - - m = Message(id=0) - m.keyring = keyring - m.request_mac = request_mac - m.xfr = xfr - m.origin = origin - m.tsig_ctx = tsig_ctx - m.multi = multi - m.first = first - - reader = _WireReader(wire, m, question_only, one_rr_per_rrset) - reader.read() - - return m - - -class _TextReader(object): - """Text format reader. - - @ivar tok: the tokenizer - @type tok: dns.tokenizer.Tokenizer object - @ivar message: The message object being built - @type message: dns.message.Message object - @ivar updating: Is the message a dynamic update? - @type updating: bool - @ivar zone_rdclass: The class of the zone in messages which are - DNS dynamic updates. - @type zone_rdclass: int - @ivar last_name: The most recently read name when building a message object - from text format. - @type last_name: dns.name.Name object - """ - - def __init__(self, text, message): - self.message = message - self.tok = dns.tokenizer.Tokenizer(text) - self.last_name = None - self.zone_rdclass = dns.rdataclass.IN - self.updating = False - - def _header_line(self, section): - """Process one line from the text format header section.""" - - token = self.tok.get() - what = token.value - if what == 'id': - self.message.id = self.tok.get_int() - elif what == 'flags': - while True: - token = self.tok.get() - if not token.is_identifier(): - self.tok.unget(token) - break - self.message.flags = self.message.flags | \ - dns.flags.from_text(token.value) - if dns.opcode.is_update(self.message.flags): - self.updating = True - elif what == 'edns': - self.message.edns = self.tok.get_int() - self.message.ednsflags = self.message.ednsflags | \ - (self.message.edns << 16) - elif what == 'eflags': - if self.message.edns < 0: - self.message.edns = 0 - while True: - token = self.tok.get() - if not token.is_identifier(): - self.tok.unget(token) - break - self.message.ednsflags = self.message.ednsflags | \ - dns.flags.edns_from_text(token.value) - elif what == 'payload': - self.message.payload = self.tok.get_int() - if self.message.edns < 0: - self.message.edns = 0 - elif what == 'opcode': - text = self.tok.get_string() - self.message.flags = self.message.flags | \ - dns.opcode.to_flags(dns.opcode.from_text(text)) - elif what == 'rcode': - text = self.tok.get_string() - self.message.set_rcode(dns.rcode.from_text(text)) - else: - raise UnknownHeaderField - self.tok.get_eol() - - def _question_line(self, section): - """Process one line from the text format question section.""" - - token = self.tok.get(want_leading = True) - if not token.is_whitespace(): - self.last_name = dns.name.from_text(token.value, None) - name = self.last_name - token = self.tok.get() - if not token.is_identifier(): - raise dns.exception.SyntaxError - # Class - try: - rdclass = dns.rdataclass.from_text(token.value) - token = self.tok.get() - if not token.is_identifier(): - raise dns.exception.SyntaxError - except dns.exception.SyntaxError: - raise dns.exception.SyntaxError - except: - rdclass = dns.rdataclass.IN - # Type - rdtype = dns.rdatatype.from_text(token.value) - self.message.find_rrset(self.message.question, name, - rdclass, rdtype, create=True, - force_unique=True) - if self.updating: - self.zone_rdclass = rdclass - self.tok.get_eol() - - def _rr_line(self, section): - """Process one line from the text format answer, authority, or - additional data sections. - """ - - deleting = None - # Name - token = self.tok.get(want_leading = True) - if not token.is_whitespace(): - self.last_name = dns.name.from_text(token.value, None) - name = self.last_name - token = self.tok.get() - if not token.is_identifier(): - raise dns.exception.SyntaxError - # TTL - try: - ttl = int(token.value, 0) - token = self.tok.get() - if not token.is_identifier(): - raise dns.exception.SyntaxError - except dns.exception.SyntaxError: - raise dns.exception.SyntaxError - except: - ttl = 0 - # Class - try: - rdclass = dns.rdataclass.from_text(token.value) - token = self.tok.get() - if not token.is_identifier(): - raise dns.exception.SyntaxError - if rdclass == dns.rdataclass.ANY or rdclass == dns.rdataclass.NONE: - deleting = rdclass - rdclass = self.zone_rdclass - except dns.exception.SyntaxError: - raise dns.exception.SyntaxError - except: - rdclass = dns.rdataclass.IN - # Type - rdtype = dns.rdatatype.from_text(token.value) - token = self.tok.get() - if not token.is_eol_or_eof(): - self.tok.unget(token) - rd = dns.rdata.from_text(rdclass, rdtype, self.tok, None) - covers = rd.covers() - else: - rd = None - covers = dns.rdatatype.NONE - rrset = self.message.find_rrset(section, name, - rdclass, rdtype, covers, - deleting, True, self.updating) - if not rd is None: - rrset.add(rd, ttl) - - def read(self): - """Read a text format DNS message and build a dns.message.Message - object.""" - - line_method = self._header_line - section = None - while 1: - token = self.tok.get(True, True) - if token.is_eol_or_eof(): - break - if token.is_comment(): - u = token.value.upper() - if u == 'HEADER': - line_method = self._header_line - elif u == 'QUESTION' or u == 'ZONE': - line_method = self._question_line - section = self.message.question - elif u == 'ANSWER' or u == 'PREREQ': - line_method = self._rr_line - section = self.message.answer - elif u == 'AUTHORITY' or u == 'UPDATE': - line_method = self._rr_line - section = self.message.authority - elif u == 'ADDITIONAL': - line_method = self._rr_line - section = self.message.additional - self.tok.get_eol() - continue - self.tok.unget(token) - line_method(section) - - -def from_text(text): - """Convert the text format message into a message object. - - @param text: The text format message. - @type text: string - @raises UnknownHeaderField: - @raises dns.exception.SyntaxError: - @rtype: dns.message.Message object""" - - # 'text' can also be a file, but we don't publish that fact - # since it's an implementation detail. The official file - # interface is from_file(). - - m = Message() - - reader = _TextReader(text, m) - reader.read() - - return m - -def from_file(f): - """Read the next text format message from the specified file. - - @param f: file or string. If I{f} is a string, it is treated - as the name of a file to open. - @raises UnknownHeaderField: - @raises dns.exception.SyntaxError: - @rtype: dns.message.Message object""" - - if sys.hexversion >= 0x02030000: - # allow Unicode filenames; turn on universal newline support - str_type = basestring - opts = 'rU' - else: - str_type = str - opts = 'r' - if isinstance(f, str_type): - f = file(f, opts) - want_close = True - else: - want_close = False - - try: - m = from_text(f) - finally: - if want_close: - f.close() - return m - -def make_query(qname, rdtype, rdclass = dns.rdataclass.IN, use_edns=None, - want_dnssec=False): - """Make a query message. - - The query name, type, and class may all be specified either - as objects of the appropriate type, or as strings. - - The query will have a randomly choosen query id, and its DNS flags - will be set to dns.flags.RD. - - @param qname: The query name. - @type qname: dns.name.Name object or string - @param rdtype: The desired rdata type. - @type rdtype: int - @param rdclass: The desired rdata class; the default is class IN. - @type rdclass: int - @param use_edns: The EDNS level to use; the default is None (no EDNS). - See the description of dns.message.Message.use_edns() for the possible - values for use_edns and their meanings. - @type use_edns: int or bool or None - @param want_dnssec: Should the query indicate that DNSSEC is desired? - @type want_dnssec: bool - @rtype: dns.message.Message object""" - - if isinstance(qname, (str, unicode)): - qname = dns.name.from_text(qname) - if isinstance(rdtype, (str, unicode)): - rdtype = dns.rdatatype.from_text(rdtype) - if isinstance(rdclass, (str, unicode)): - rdclass = dns.rdataclass.from_text(rdclass) - m = Message() - m.flags |= dns.flags.RD - m.find_rrset(m.question, qname, rdclass, rdtype, create=True, - force_unique=True) - m.use_edns(use_edns) - m.want_dnssec(want_dnssec) - return m - -def make_response(query, recursion_available=False, our_payload=8192): - """Make a message which is a response for the specified query. - The message returned is really a response skeleton; it has all - of the infrastructure required of a response, but none of the - content. - - The response's question section is a shallow copy of the query's - question section, so the query's question RRsets should not be - changed. - - @param query: the query to respond to - @type query: dns.message.Message object - @param recursion_available: should RA be set in the response? - @type recursion_available: bool - @param our_payload: payload size to advertise in EDNS responses; default - is 8192. - @type our_payload: int - @rtype: dns.message.Message object""" - - if query.flags & dns.flags.QR: - raise dns.exception.FormError('specified query message is not a query') - response = dns.message.Message(query.id) - response.flags = dns.flags.QR | (query.flags & dns.flags.RD) - if recursion_available: - response.flags |= dns.flags.RA - response.set_opcode(query.opcode()) - response.question = list(query.question) - if query.edns >= 0: - response.use_edns(0, 0, our_payload, query.payload) - if not query.keyname is None: - response.keyname = query.keyname - response.keyring = query.keyring - response.request_mac = query.mac - return response |