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87 lines
3.5 KiB
87 lines
3.5 KiB
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
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# Copyright (C) 2010, 2011 Nominum, Inc.
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#
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# Permission to use, copy, modify, and distribute this software and its
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# documentation for any purpose with or without fee is hereby granted,
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# provided that the above copyright notice and this permission notice
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# appear in all copies.
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#
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# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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import struct
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import binascii
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import dns.dnssec
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import dns.immutable
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import dns.rdata
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import dns.rdatatype
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@dns.immutable.immutable
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class DSBase(dns.rdata.Rdata):
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"""Base class for rdata that is like a DS record"""
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__slots__ = ['key_tag', 'algorithm', 'digest_type', 'digest']
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# Digest types registry: https://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml
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_digest_length_by_type = {
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1: 20, # SHA-1, RFC 3658 Sec. 2.4
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2: 32, # SHA-256, RFC 4509 Sec. 2.2
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3: 32, # GOST R 34.11-94, RFC 5933 Sec. 4 in conjunction with RFC 4490 Sec. 2.1
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4: 48, # SHA-384, RFC 6605 Sec. 2
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}
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def __init__(self, rdclass, rdtype, key_tag, algorithm, digest_type,
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digest):
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super().__init__(rdclass, rdtype)
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self.key_tag = self._as_uint16(key_tag)
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self.algorithm = dns.dnssec.Algorithm.make(algorithm)
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self.digest_type = self._as_uint8(digest_type)
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self.digest = self._as_bytes(digest)
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try:
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if len(self.digest) != self._digest_length_by_type[self.digest_type]:
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raise ValueError('digest length inconsistent with digest type')
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except KeyError:
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if self.digest_type == 0: # reserved, RFC 3658 Sec. 2.4
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raise ValueError('digest type 0 is reserved')
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def to_text(self, origin=None, relativize=True, **kw):
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kw = kw.copy()
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chunksize = kw.pop('chunksize', 128)
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return '%d %d %d %s' % (self.key_tag, self.algorithm,
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self.digest_type,
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dns.rdata._hexify(self.digest,
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chunksize=chunksize,
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**kw))
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@classmethod
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def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True,
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relativize_to=None):
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key_tag = tok.get_uint16()
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algorithm = tok.get_string()
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digest_type = tok.get_uint8()
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digest = tok.concatenate_remaining_identifiers().encode()
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digest = binascii.unhexlify(digest)
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return cls(rdclass, rdtype, key_tag, algorithm, digest_type,
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digest)
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def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
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header = struct.pack("!HBB", self.key_tag, self.algorithm,
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self.digest_type)
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file.write(header)
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file.write(self.digest)
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@classmethod
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def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
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header = parser.get_struct("!HBB")
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digest = parser.get_remaining()
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return cls(rdclass, rdtype, header[0], header[1], header[2], digest)
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