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# 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 dns.rdata
import dns.rdatatype
class DSBase(dns.rdata.Rdata):
"""Base class for rdata that is like a DS record
@ivar key_tag: the key tag
@type key_tag: int
@ivar algorithm: the algorithm
@type algorithm: int
@ivar digest_type: the digest type
@type digest_type: int
@ivar digest: the digest
@type digest: int
@see: draft-ietf-dnsext-delegation-signer-14.txt"""
__slots__ = ['key_tag', 'algorithm', 'digest_type', 'digest']
def __init__(self, rdclass, rdtype, key_tag, algorithm, digest_type,
digest):
super(DSBase, self).__init__(rdclass, rdtype)
self.key_tag = key_tag
self.algorithm = algorithm
self.digest_type = digest_type
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))
def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
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)
digest = ''.join(chunks)
digest = digest.decode('hex_codec')
return cls(rdclass, rdtype, key_tag, algorithm, digest_type,
digest)
from_text = classmethod(from_text)
def to_wire(self, file, compress = None, origin = None):
header = struct.pack("!HBB", self.key_tag, self.algorithm,
self.digest_type)
file.write(header)
file.write(self.digest)
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)
from_wire = classmethod(from_wire)
def _cmp(self, other):
hs = struct.pack("!HBB", self.key_tag, self.algorithm,
self.digest_type)
ho = struct.pack("!HBB", other.key_tag, other.algorithm,
other.digest_type)
v = cmp(hs, ho)
if v == 0:
v = cmp(self.digest, other.digest)
return v
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