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basabuuka_prototyp/venv/lib/python3.5/site-packages/dns/message.py

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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2001-2017 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"""
from __future__ import absolute_import
from io import StringIO
import struct
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
from ._compat import long, xrange, string_types
class ShortHeader(dns.exception.FormError):
"""The DNS packet passed to from_wire() is too short."""
class TrailingJunk(dns.exception.FormError):
"""The DNS packet passed to from_wire() has extra junk at the end of it."""
class UnknownHeaderField(dns.exception.DNSException):
"""The header field name was not recognized when converting from text
into a message."""
class BadEDNS(dns.exception.FormError):
"""An OPT record occurred somewhere other than the start of
the additional data section."""
class BadTSIG(dns.exception.FormError):
"""A TSIG record occurred somewhere other than the end of
the additional data section."""
class UnknownTSIGKey(dns.exception.DNSException):
"""A TSIG with an unknown key was received."""
#: The question section number
QUESTION = 0
#: The answer section number
ANSWER = 1
#: The authority section number
AUTHORITY = 2
#: The additional section number
ADDITIONAL = 3
class Message(object):
"""A DNS message."""
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 = b''
self.other_data = b''
self.tsig_error = 0
self.fudge = 300
self.original_id = self.id
self.mac = b''
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 ' + repr(self.id) + '>'
def __str__(self):
return self.to_text()
def to_text(self, origin=None, relativize=True, **kw):
"""Convert the message to text.
The *origin*, *relativize*, and any other keyword
arguments are passed to the RRset ``to_wire()`` method.
Returns a ``text``.
"""
s = StringIO()
s.write(u'id %d\n' % self.id)
s.write(u'opcode %s\n' %
dns.opcode.to_text(dns.opcode.from_flags(self.flags)))
rc = dns.rcode.from_flags(self.flags, self.ednsflags)
s.write(u'rcode %s\n' % dns.rcode.to_text(rc))
s.write(u'flags %s\n' % dns.flags.to_text(self.flags))
if self.edns >= 0:
s.write(u'edns %s\n' % self.edns)
if self.ednsflags != 0:
s.write(u'eflags %s\n' %
dns.flags.edns_to_text(self.ednsflags))
s.write(u'payload %d\n' % self.payload)
for opt in self.options:
s.write(u'option %s\n' % opt.to_text())
is_update = dns.opcode.is_update(self.flags)
if is_update:
s.write(u';ZONE\n')
else:
s.write(u';QUESTION\n')
for rrset in self.question:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
if is_update:
s.write(u';PREREQ\n')
else:
s.write(u';ANSWER\n')
for rrset in self.answer:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
if is_update:
s.write(u';UPDATE\n')
else:
s.write(u';AUTHORITY\n')
for rrset in self.authority:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
s.write(u';ADDITIONAL\n')
for rrset in self.additional:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
#
# 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.
Returns a ``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):
return not self.__eq__(other)
def is_response(self, other):
"""Is this message a response to *other*?
Returns a ``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):
"""Return the "section number" of the specified section for use
in indexing. The question section is 0, the answer section is 1,
the authority section is 2, and the additional section is 3.
*section* is one of the section attributes of this message.
Raises ``ValueError`` if the section isn't known.
Returns an ``int``.
"""
if section is self.question:
return QUESTION
elif section is self.answer:
return ANSWER
elif section is self.authority:
return AUTHORITY
elif section is self.additional:
return ADDITIONAL
else:
raise ValueError('unknown section')
def section_from_number(self, number):
"""Return the "section number" of the specified section for use
in indexing. The question section is 0, the answer section is 1,
the authority section is 2, and the additional section is 3.
*section* is one of the section attributes of this message.
Raises ``ValueError`` if the section isn't known.
Returns an ``int``.
"""
if number == QUESTION:
return self.question
elif number == ANSWER:
return self.answer
elif number == AUTHORITY:
return self.authority
elif number == ADDITIONAL:
return self.additional
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.
*section*, an ``int`` section number, or one of the section
attributes of this message. This specifies the
the section of the message to search. For example::
my_message.find_rrset(my_message.answer, name, rdclass, rdtype)
my_message.find_rrset(dns.message.ANSWER, name, rdclass, rdtype)
*name*, a ``dns.name.Name``, the name of the RRset.
*rdclass*, an ``int``, the class of the RRset.
*rdtype*, an ``int``, the type of the RRset.
*covers*, an ``int`` or ``None``, the covers value of the RRset.
The default is ``None``.
*deleting*, an ``int`` or ``None``, the deleting value of the RRset.
The default is ``None``.
*create*, a ``bool``. If ``True``, create the RRset if it is not found.
The created RRset is appended to *section*.
*force_unique*, a ``bool``. If ``True`` and *create* is also ``True``,
create a new RRset regardless of whether a matching RRset exists
already. The default is ``False``. This is useful when creating
DDNS Update messages, as order matters for them.
Raises ``KeyError`` if the RRset was not found and create was
``False``.
Returns a ``dns.rrset.RRset object``.
"""
if isinstance(section, int):
section_number = section
section = self.section_from_number(section_number)
else:
section_number = self.section_number(section)
key = (section_number, name, rdclass, rdtype, covers, deleting)
if not force_unique:
if self.index is not None:
rrset = self.index.get(key)
if rrset is not 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 self.index is not 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.
*section*, an ``int`` section number, or one of the section
attributes of this message. This specifies the
the section of the message to search. For example::
my_message.get_rrset(my_message.answer, name, rdclass, rdtype)
my_message.get_rrset(dns.message.ANSWER, name, rdclass, rdtype)
*name*, a ``dns.name.Name``, the name of the RRset.
*rdclass*, an ``int``, the class of the RRset.
*rdtype*, an ``int``, the type of the RRset.
*covers*, an ``int`` or ``None``, the covers value of the RRset.
The default is ``None``.
*deleting*, an ``int`` or ``None``, the deleting value of the RRset.
The default is ``None``.
*create*, a ``bool``. If ``True``, create the RRset if it is not found.
The created RRset is appended to *section*.
*force_unique*, a ``bool``. If ``True`` and *create* is also ``True``,
create a new RRset regardless of whether a matching RRset exists
already. The default is ``False``. This is useful when creating
DDNS Update messages, as order matters for them.
Returns a ``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.
*origin*, a ``dns.name.Name`` or ``None``, the origin to be appended
to any relative names.
*max_size*, an ``int``, the maximum size of the wire format
output; default is 0, which means "the message's request
payload, if nonzero, or 65535".
Raises ``dns.exception.TooBig`` if *max_size* was exceeded.
Returns a ``binary``.
"""
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 self.keyname is not 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=b'',
algorithm=dns.tsig.default_algorithm):
"""When sending, a TSIG signature using the specified keyring
and keyname should be added.
See the documentation of the Message class for a complete
description of the keyring dictionary.
*keyring*, a ``dict``, the TSIG keyring to use. 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.
*keyname*, a ``dns.name.Name`` or ``None``, the name of the TSIG key
to use; defaults to ``None``. The key must be defined in the keyring.
*fudge*, an ``int``, the TSIG time fudge.
*original_id*, an ``int``, the TSIG original id. If ``None``,
the message's id is used.
*tsig_error*, an ``int``, the TSIG error code.
*other_data*, a ``binary``, the TSIG other data.
*algorithm*, a ``dns.name.Name``, the TSIG algorithm to use.
"""
self.keyring = keyring
if keyname is None:
self.keyname = list(self.keyring.keys())[0]
else:
if isinstance(keyname, string_types):
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.
*edns*, an ``int``, is 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".
*ednsflags*, an ``int``, the EDNS flag values.
*payload*, an ``int``, is the EDNS sender's payload field, which is the
maximum size of UDP datagram the sender can handle. I.e. how big
a response to this message can be.
*request_payload*, an ``int``, is the EDNS payload size to use when
sending this message. If not specified, defaults to the value of
*payload*.
*options*, a list of ``dns.edns.Option`` objects or ``None``, the EDNS
options.
"""
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 &= long(0xFF00FFFF)
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.
*wanted*, a ``bool``. If ``True``, then DNSSEC data is
desired in the response, EDNS is enabled if required, and then
the DO bit is set. If ``False``, the DO bit is cleared if
EDNS is enabled.
"""
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.
Returns an ``int``.
"""
return dns.rcode.from_flags(self.flags, self.ednsflags)
def set_rcode(self, rcode):
"""Set the rcode.
*rcode*, an ``int``, is the rcode to set.
"""
(value, evalue) = dns.rcode.to_flags(rcode)
self.flags &= 0xFFF0
self.flags |= value
self.ednsflags &= long(0x00FFFFFF)
self.ednsflags |= evalue
if self.ednsflags != 0 and self.edns < 0:
self.edns = 0
def opcode(self):
"""Return the opcode.
Returns an ``int``.
"""
return dns.opcode.from_flags(self.flags)
def set_opcode(self, opcode):
"""Set the opcode.
*opcode*, an ``int``, is the opcode to set.
"""
self.flags &= 0x87FF
self.flags |= dns.opcode.to_flags(opcode)
class _WireReader(object):
"""Wire format reader.
wire: a binary, is the wire-format message.
message: The message object being built
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.
updating: Is the message a dynamic update?
one_rr_per_rrset: Put each RR into its own RRset?
ignore_trailing: Ignore trailing junk at end of request?
zone_rdclass: The class of the zone in messages which are
DNS dynamic updates.
"""
def __init__(self, wire, message, question_only=False,
one_rr_per_rrset=False, ignore_trailing=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
self.ignore_trailing = ignore_trailing
def _get_question(self, qcount):
"""Read the next *qcount* records from the wire data and add them to
the question section.
"""
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 self.message.origin is not 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.
section: the section of the message to which to add records
count: the number of records to read
"""
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 self.message.origin is not 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 section is not 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.keyname = absolute_name
(self.message.keyalgorithm, self.message.mac) = \
dns.tsig.get_algorithm_and_mac(self.wire, self.current,
rdlen)
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 rd is not 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 not self.ignore_trailing and 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=b'', xfr=False, origin=None,
tsig_ctx=None, multi=False, first=True,
question_only=False, one_rr_per_rrset=False,
ignore_trailing=False):
"""Convert a DNS wire format message into a message
object.
*keyring*, a ``dict``, the keyring to use if the message is signed.
*request_mac*, a ``binary``. If the message is a response to a
TSIG-signed request, *request_mac* should be set to the MAC of
that request.
*xfr*, a ``bool``, should be set to ``True`` if this message is part of
a zone transfer.
*origin*, a ``dns.name.Name`` or ``None``. If the message is part
of a zone transfer, *origin* should be the origin name of the
zone.
*tsig_ctx*, a ``hmac.HMAC`` objext, the ongoing TSIG context, used
when validating zone transfers.
*multi*, a ``bool``, should be set to ``True`` if this message
part of a multiple message sequence.
*first*, a ``bool``, should be set to ``True`` if this message is
stand-alone, or the first message in a multi-message sequence.
*question_only*, a ``bool``. If ``True``, read only up to
the end of the question section.
*one_rr_per_rrset*, a ``bool``. If ``True``, put each RR into its
own RRset.
*ignore_trailing*, a ``bool``. If ``True``, ignore trailing
junk at end of the message.
Raises ``dns.message.ShortHeader`` if the message is less than 12 octets
long.
Raises ``dns.messaage.TrailingJunk`` if there were octets in the message
past the end of the proper DNS message, and *ignore_trailing* is ``False``.
Raises ``dns.message.BadEDNS`` if an OPT record was in the
wrong section, or occurred more than once.
Raises ``dns.message.BadTSIG`` if a TSIG record was not the last
record of the additional data section.
Returns a ``dns.message.Message``.
"""
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,
ignore_trailing)
reader.read()
return m
class _TextReader(object):
"""Text format reader.
tok: the tokenizer.
message: The message object being built.
updating: Is the message a dynamic update?
zone_rdclass: The class of the zone in messages which are
DNS dynamic updates.
last_name: The most recently read name when building a message 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 Exception:
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 Exception:
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 Exception:
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 rd is not 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.
*text*, a ``text``, the text format message.
Raises ``dns.message.UnknownHeaderField`` if a header is unknown.
Raises ``dns.exception.SyntaxError`` if the text is badly formed.
Returns a ``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.
*f*, a ``file`` or ``text``. If *f* is text, it is treated as the
pathname of a file to open.
Raises ``dns.message.UnknownHeaderField`` if a header is unknown.
Raises ``dns.exception.SyntaxError`` if the text is badly formed.
Returns a ``dns.message.Message object``
"""
str_type = string_types
opts = 'rU'
if isinstance(f, str_type):
f = open(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, ednsflags=None, payload=None,
request_payload=None, options=None):
"""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 chosen query id, and its DNS flags
will be set to dns.flags.RD.
qname, a ``dns.name.Name`` or ``text``, the query name.
*rdtype*, an ``int`` or ``text``, the desired rdata type.
*rdclass*, an ``int`` or ``text``, the desired rdata class; the default
is class IN.
*use_edns*, an ``int``, ``bool`` or ``None``. 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.
*want_dnssec*, a ``bool``. If ``True``, DNSSEC data is desired.
*ednsflags*, an ``int``, the EDNS flag values.
*payload*, an ``int``, is the EDNS sender's payload field, which is the
maximum size of UDP datagram the sender can handle. I.e. how big
a response to this message can be.
*request_payload*, an ``int``, is the EDNS payload size to use when
sending this message. If not specified, defaults to the value of
*payload*.
*options*, a list of ``dns.edns.Option`` objects or ``None``, the EDNS
options.
Returns a ``dns.message.Message``
"""
if isinstance(qname, string_types):
qname = dns.name.from_text(qname)
if isinstance(rdtype, string_types):
rdtype = dns.rdatatype.from_text(rdtype)
if isinstance(rdclass, string_types):
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)
# only pass keywords on to use_edns if they have been set to a
# non-None value. Setting a field will turn EDNS on if it hasn't
# been configured.
kwargs = {}
if ednsflags is not None:
kwargs['ednsflags'] = ednsflags
if use_edns is None:
use_edns = 0
if payload is not None:
kwargs['payload'] = payload
if use_edns is None:
use_edns = 0
if request_payload is not None:
kwargs['request_payload'] = request_payload
if use_edns is None:
use_edns = 0
if options is not None:
kwargs['options'] = options
if use_edns is None:
use_edns = 0
kwargs['edns'] = use_edns
m.use_edns(**kwargs)
m.want_dnssec(want_dnssec)
return m
def make_response(query, recursion_available=False, our_payload=8192,
fudge=300):
"""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.
*query*, a ``dns.message.Message``, the query to respond to.
*recursion_available*, a ``bool``, should RA be set in the response?
*our_payload*, an ``int``, the payload size to advertise in EDNS
responses.
*fudge*, an ``int``, the TSIG time fudge.
Returns a ``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 query.had_tsig:
response.use_tsig(query.keyring, query.keyname, fudge, None, 0, b'',
query.keyalgorithm)
response.request_mac = query.mac
return response