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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2004-2017 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.
import base64
import binascii
import struct
import dns.exception
import dns.immutable
import dns.name
import dns.rdata
import dns.rdatatype
import dns.rdtypes.util
b32_hex_to_normal = bytes.maketrans(
b"0123456789ABCDEFGHIJKLMNOPQRSTUV", b"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
)
b32_normal_to_hex = bytes.maketrans(
b"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567", b"0123456789ABCDEFGHIJKLMNOPQRSTUV"
)
# hash algorithm constants
SHA1 = 1
# flag constants
OPTOUT = 1
@dns.immutable.immutable
class Bitmap(dns.rdtypes.util.Bitmap):
type_name = "NSEC3"
@dns.immutable.immutable
class NSEC3(dns.rdata.Rdata):
"""NSEC3 record"""
__slots__ = ["algorithm", "flags", "iterations", "salt", "next", "windows"]
def __init__(
self, rdclass, rdtype, algorithm, flags, iterations, salt, next, windows
):
super().__init__(rdclass, rdtype)
self.algorithm = self._as_uint8(algorithm)
self.flags = self._as_uint8(flags)
self.iterations = self._as_uint16(iterations)
self.salt = self._as_bytes(salt, True, 255)
self.next = self._as_bytes(next, True, 255)
if not isinstance(windows, Bitmap):
windows = Bitmap(windows)
self.windows = tuple(windows.windows)
def _next_text(self):
next = base64.b32encode(self.next).translate(b32_normal_to_hex).lower().decode()
next = next.rstrip("=")
return next
def to_text(self, origin=None, relativize=True, **kw):
next = self._next_text()
if self.salt == b"":
salt = "-"
else:
salt = binascii.hexlify(self.salt).decode()
text = Bitmap(self.windows).to_text()
return f"{self.algorithm} {self.flags} {self.iterations} {salt} {next}{text}"
@classmethod
def from_text(
cls, rdclass, rdtype, tok, origin=None, relativize=True, relativize_to=None
):
algorithm = tok.get_uint8()
flags = tok.get_uint8()
iterations = tok.get_uint16()
salt = tok.get_string()
if salt == "-":
salt = b""
else:
salt = binascii.unhexlify(salt.encode("ascii"))
next = tok.get_string().encode("ascii").upper().translate(b32_hex_to_normal)
if next.endswith(b"="):
raise binascii.Error("Incorrect padding")
if len(next) % 8 != 0:
next += b"=" * (8 - len(next) % 8)
next = base64.b32decode(next)
bitmap = Bitmap.from_text(tok)
return cls(rdclass, rdtype, algorithm, flags, iterations, salt, next, bitmap)
def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
l = len(self.salt)
file.write(struct.pack("!BBHB", self.algorithm, self.flags, self.iterations, l))
file.write(self.salt)
l = len(self.next)
file.write(struct.pack("!B", l))
file.write(self.next)
Bitmap(self.windows).to_wire(file)
@classmethod
def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
(algorithm, flags, iterations) = parser.get_struct("!BBH")
salt = parser.get_counted_bytes()
next = parser.get_counted_bytes()
bitmap = Bitmap.from_wire_parser(parser)
return cls(rdclass, rdtype, algorithm, flags, iterations, salt, next, bitmap)
def next_name(self, origin=None):
return dns.name.from_text(self._next_text(), origin)
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