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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2010, 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.
import struct
import binascii
import dns.rdata
import dns.rdatatype
class DSBase(dns.rdata.Rdata):
"""Base class for rdata that is like a DS record"""
__slots__ = ['key_tag', 'algorithm', 'digest_type', 'digest']
def __init__(self, rdclass, rdtype, key_tag, algorithm, digest_type,
digest):
super().__init__(rdclass, rdtype)
object.__setattr__(self, 'key_tag', key_tag)
object.__setattr__(self, 'algorithm', algorithm)
object.__setattr__(self, 'digest_type', digest_type)
object.__setattr__(self, 'digest', digest)
def to_text(self, origin=None, relativize=True, **kw):
return '%d %d %d %s' % (self.key_tag, self.algorithm,
self.digest_type,
dns.rdata._hexify(self.digest,
chunksize=128))
@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True,
relativize_to=None):
key_tag = tok.get_uint16()
algorithm = tok.get_uint8()
digest_type = tok.get_uint8()
chunks = []
while 1:
t = tok.get().unescape()
if t.is_eol_or_eof():
break
if not t.is_identifier():
raise dns.exception.SyntaxError
chunks.append(t.value.encode())
digest = b''.join(chunks)
digest = binascii.unhexlify(digest)
return cls(rdclass, rdtype, key_tag, algorithm, digest_type,
digest)
def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
header = struct.pack("!HBB", self.key_tag, self.algorithm,
self.digest_type)
file.write(header)
file.write(self.digest)
@classmethod
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
header = struct.unpack("!HBB", wire[current: current + 4])
current += 4
rdlen -= 4
digest = wire[current: current + rdlen].unwrap()
return cls(rdclass, rdtype, header[0], header[1], header[2], digest)
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