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Enso-Bot/venv/Lib/site-packages/dns/rdata.py

457 lines
14 KiB
Python

# 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 rdata."""
from io import BytesIO
import base64
import binascii
import dns.exception
import dns.name
import dns.rdataclass
import dns.rdatatype
import dns.tokenizer
import dns.wiredata
from ._compat import xrange, string_types, text_type
try:
import threading as _threading
except ImportError:
import dummy_threading as _threading
_hex_chunksize = 32
def _hexify(data, chunksize=_hex_chunksize):
"""Convert a binary string into its hex encoding, broken up into chunks
of chunksize characters separated by a space.
"""
line = binascii.hexlify(data)
return b' '.join([line[i:i + chunksize]
for i
in range(0, len(line), chunksize)]).decode()
_base64_chunksize = 32
def _base64ify(data, chunksize=_base64_chunksize):
"""Convert a binary string into its base64 encoding, broken up into chunks
of chunksize characters separated by a space.
"""
line = base64.b64encode(data)
return b' '.join([line[i:i + chunksize]
for i
in range(0, len(line), chunksize)]).decode()
__escaped = bytearray(b'"\\')
def _escapify(qstring):
"""Escape the characters in a quoted string which need it."""
if isinstance(qstring, text_type):
qstring = qstring.encode()
if not isinstance(qstring, bytearray):
qstring = bytearray(qstring)
text = ''
for c in qstring:
if c in __escaped:
text += '\\' + chr(c)
elif c >= 0x20 and c < 0x7F:
text += chr(c)
else:
text += '\\%03d' % c
return text
def _truncate_bitmap(what):
"""Determine the index of greatest byte that isn't all zeros, and
return the bitmap that contains all the bytes less than that index.
"""
for i in xrange(len(what) - 1, -1, -1):
if what[i] != 0:
return what[0: i + 1]
return what[0:1]
class Rdata(object):
"""Base class for all DNS rdata types."""
__slots__ = ['rdclass', 'rdtype']
def __init__(self, rdclass, rdtype):
"""Initialize an rdata.
*rdclass*, an ``int`` is the rdataclass of the Rdata.
*rdtype*, an ``int`` is the rdatatype of the Rdata.
"""
self.rdclass = rdclass
self.rdtype = rdtype
def covers(self):
"""Return the type a Rdata covers.
DNS SIG/RRSIG rdatas apply to a specific type; this type is
returned by the covers() function. If the rdata type is not
SIG or RRSIG, dns.rdatatype.NONE is returned. This is useful when
creating rdatasets, allowing the rdataset to contain only RRSIGs
of a particular type, e.g. RRSIG(NS).
Returns an ``int``.
"""
return dns.rdatatype.NONE
def extended_rdatatype(self):
"""Return a 32-bit type value, the least significant 16 bits of
which are the ordinary DNS type, and the upper 16 bits of which are
the "covered" type, if any.
Returns an ``int``.
"""
return self.covers() << 16 | self.rdtype
def to_text(self, origin=None, relativize=True, **kw):
"""Convert an rdata to text format.
Returns a ``text``.
"""
raise NotImplementedError
def to_wire(self, file, compress=None, origin=None):
"""Convert an rdata to wire format.
Returns a ``binary``.
"""
raise NotImplementedError
def to_digestable(self, origin=None):
"""Convert rdata to a format suitable for digesting in hashes. This
is also the DNSSEC canonical form.
Returns a ``binary``.
"""
f = BytesIO()
self.to_wire(f, None, origin)
return f.getvalue()
def validate(self):
"""Check that the current contents of the rdata's fields are
valid.
If you change an rdata by assigning to its fields,
it is a good idea to call validate() when you are done making
changes.
Raises various exceptions if there are problems.
Returns ``None``.
"""
dns.rdata.from_text(self.rdclass, self.rdtype, self.to_text())
def __repr__(self):
covers = self.covers()
if covers == dns.rdatatype.NONE:
ctext = ''
else:
ctext = '(' + dns.rdatatype.to_text(covers) + ')'
return '<DNS ' + dns.rdataclass.to_text(self.rdclass) + ' ' + \
dns.rdatatype.to_text(self.rdtype) + ctext + ' rdata: ' + \
str(self) + '>'
def __str__(self):
return self.to_text()
def _cmp(self, other):
"""Compare an rdata with another rdata of the same rdtype and
rdclass.
Return < 0 if self < other in the DNSSEC ordering, 0 if self
== other, and > 0 if self > other.
"""
our = self.to_digestable(dns.name.root)
their = other.to_digestable(dns.name.root)
if our == their:
return 0
elif our > their:
return 1
else:
return -1
def __eq__(self, other):
if not isinstance(other, Rdata):
return False
if self.rdclass != other.rdclass or self.rdtype != other.rdtype:
return False
return self._cmp(other) == 0
def __ne__(self, other):
if not isinstance(other, Rdata):
return True
if self.rdclass != other.rdclass or self.rdtype != other.rdtype:
return True
return self._cmp(other) != 0
def __lt__(self, other):
if not isinstance(other, Rdata) or \
self.rdclass != other.rdclass or self.rdtype != other.rdtype:
return NotImplemented
return self._cmp(other) < 0
def __le__(self, other):
if not isinstance(other, Rdata) or \
self.rdclass != other.rdclass or self.rdtype != other.rdtype:
return NotImplemented
return self._cmp(other) <= 0
def __ge__(self, other):
if not isinstance(other, Rdata) or \
self.rdclass != other.rdclass or self.rdtype != other.rdtype:
return NotImplemented
return self._cmp(other) >= 0
def __gt__(self, other):
if not isinstance(other, Rdata) or \
self.rdclass != other.rdclass or self.rdtype != other.rdtype:
return NotImplemented
return self._cmp(other) > 0
def __hash__(self):
return hash(self.to_digestable(dns.name.root))
@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
raise NotImplementedError
@classmethod
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
raise NotImplementedError
def choose_relativity(self, origin=None, relativize=True):
"""Convert any domain names in the rdata to the specified
relativization.
"""
class GenericRdata(Rdata):
"""Generic Rdata Class
This class is used for rdata types for which we have no better
implementation. It implements the DNS "unknown RRs" scheme.
"""
__slots__ = ['data']
def __init__(self, rdclass, rdtype, data):
super(GenericRdata, self).__init__(rdclass, rdtype)
self.data = data
def to_text(self, origin=None, relativize=True, **kw):
return r'\# %d ' % len(self.data) + _hexify(self.data)
@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
token = tok.get()
if not token.is_identifier() or token.value != r'\#':
raise dns.exception.SyntaxError(
r'generic rdata does not start with \#')
length = tok.get_int()
chunks = []
while 1:
token = tok.get()
if token.is_eol_or_eof():
break
chunks.append(token.value.encode())
hex = b''.join(chunks)
data = binascii.unhexlify(hex)
if len(data) != length:
raise dns.exception.SyntaxError(
'generic rdata hex data has wrong length')
return cls(rdclass, rdtype, data)
def to_wire(self, file, compress=None, origin=None):
file.write(self.data)
@classmethod
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
return cls(rdclass, rdtype, wire[current: current + rdlen])
_rdata_modules = {}
_module_prefix = 'dns.rdtypes'
_import_lock = _threading.Lock()
def get_rdata_class(rdclass, rdtype):
def import_module(name):
with _import_lock:
mod = __import__(name)
components = name.split('.')
for comp in components[1:]:
mod = getattr(mod, comp)
return mod
mod = _rdata_modules.get((rdclass, rdtype))
rdclass_text = dns.rdataclass.to_text(rdclass)
rdtype_text = dns.rdatatype.to_text(rdtype)
rdtype_text = rdtype_text.replace('-', '_')
if not mod:
mod = _rdata_modules.get((dns.rdatatype.ANY, rdtype))
if not mod:
try:
mod = import_module('.'.join([_module_prefix,
rdclass_text, rdtype_text]))
_rdata_modules[(rdclass, rdtype)] = mod
except ImportError:
try:
mod = import_module('.'.join([_module_prefix,
'ANY', rdtype_text]))
_rdata_modules[(dns.rdataclass.ANY, rdtype)] = mod
except ImportError:
mod = None
if mod:
cls = getattr(mod, rdtype_text)
else:
cls = GenericRdata
return cls
def from_text(rdclass, rdtype, tok, origin=None, relativize=True):
"""Build an rdata object from text format.
This function attempts to dynamically load a class which
implements the specified rdata class and type. If there is no
class-and-type-specific implementation, the GenericRdata class
is used.
Once a class is chosen, its from_text() class method is called
with the parameters to this function.
If *tok* is a ``text``, then a tokenizer is created and the string
is used as its input.
*rdclass*, an ``int``, the rdataclass.
*rdtype*, an ``int``, the rdatatype.
*tok*, a ``dns.tokenizer.Tokenizer`` or a ``text``.
*origin*, a ``dns.name.Name`` (or ``None``), the
origin to use for relative names.
*relativize*, a ``bool``. If true, name will be relativized to
the specified origin.
Returns an instance of the chosen Rdata subclass.
"""
if isinstance(tok, string_types):
tok = dns.tokenizer.Tokenizer(tok)
cls = get_rdata_class(rdclass, rdtype)
if cls != GenericRdata:
# peek at first token
token = tok.get()
tok.unget(token)
if token.is_identifier() and \
token.value == r'\#':
#
# Known type using the generic syntax. Extract the
# wire form from the generic syntax, and then run
# from_wire on it.
#
rdata = GenericRdata.from_text(rdclass, rdtype, tok, origin,
relativize)
return from_wire(rdclass, rdtype, rdata.data, 0, len(rdata.data),
origin)
return cls.from_text(rdclass, rdtype, tok, origin, relativize)
def from_wire(rdclass, rdtype, wire, current, rdlen, origin=None):
"""Build an rdata object from wire format
This function attempts to dynamically load a class which
implements the specified rdata class and type. If there is no
class-and-type-specific implementation, the GenericRdata class
is used.
Once a class is chosen, its from_wire() class method is called
with the parameters to this function.
*rdclass*, an ``int``, the rdataclass.
*rdtype*, an ``int``, the rdatatype.
*wire*, a ``binary``, the wire-format message.
*current*, an ``int``, the offset in wire of the beginning of
the rdata.
*rdlen*, an ``int``, the length of the wire-format rdata
*origin*, a ``dns.name.Name`` (or ``None``). If not ``None``,
then names will be relativized to this origin.
Returns an instance of the chosen Rdata subclass.
"""
wire = dns.wiredata.maybe_wrap(wire)
cls = get_rdata_class(rdclass, rdtype)
return cls.from_wire(rdclass, rdtype, wire, current, rdlen, origin)
class RdatatypeExists(dns.exception.DNSException):
"""DNS rdatatype already exists."""
supp_kwargs = {'rdclass', 'rdtype'}
fmt = "The rdata type with class {rdclass} and rdtype {rdtype} " + \
"already exists."
def register_type(implementation, rdtype, rdtype_text, is_singleton=False,
rdclass=dns.rdataclass.IN):
"""Dynamically register a module to handle an rdatatype.
*implementation*, a module implementing the type in the usual dnspython
way.
*rdtype*, an ``int``, the rdatatype to register.
*rdtype_text*, a ``text``, the textual form of the rdatatype.
*is_singleton*, a ``bool``, indicating if the type is a singleton (i.e.
RRsets of the type can have only one member.)
*rdclass*, the rdataclass of the type, or ``dns.rdataclass.ANY`` if
it applies to all classes.
"""
existing_cls = get_rdata_class(rdclass, rdtype)
if existing_cls != GenericRdata:
raise RdatatypeExists(rdclass=rdclass, rdtype=rdtype)
_rdata_modules[(rdclass, rdtype)] = implementation
dns.rdatatype.register_type(rdtype, rdtype_text, is_singleton)