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# Copyright (C) 2004-2007, 2009-2011 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.exception
import dns.dnssec
import dns.rdata
# flag constants
SEP = 0x0001
REVOKE = 0x0080
ZONE = 0x0100
_flag_by_text = {
'SEP': SEP,
'REVOKE': REVOKE,
'ZONE': ZONE
}
# We construct the inverse mapping programmatically to ensure that we
# cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
# would cause the mapping not to be true inverse.
_flag_by_value = dict([(y, x) for x, y in _flag_by_text.iteritems()])
def flags_to_text_set(flags):
"""Convert a DNSKEY flags value to set texts
@rtype: set([string])"""
flags_set = set()
mask = 0x1
while mask <= 0x8000:
if flags & mask:
text = _flag_by_value.get(mask)
if not text:
text = hex(mask)
flags_set.add(text)
mask <<= 1
return flags_set
def flags_from_text_set(texts_set):
"""Convert set of DNSKEY flag mnemonic texts to DNSKEY flag value
@rtype: int"""
flags = 0
for text in texts_set:
try:
flags += _flag_by_text[text]
except KeyError:
raise NotImplementedError(
"DNSKEY flag '%s' is not supported" % text)
return flags
class DNSKEY(dns.rdata.Rdata):
"""DNSKEY record
@ivar flags: the key flags
@type flags: int
@ivar protocol: the protocol for which this key may be used
@type protocol: int
@ivar algorithm: the algorithm used for the key
@type algorithm: int
@ivar key: the public key
@type key: string"""
__slots__ = ['flags', 'protocol', 'algorithm', 'key']
def __init__(self, rdclass, rdtype, flags, protocol, algorithm, key):
super(DNSKEY, self).__init__(rdclass, rdtype)
self.flags = flags
self.protocol = protocol
self.algorithm = algorithm
self.key = key
def to_text(self, origin=None, relativize=True, **kw):
return '%d %d %d %s' % (self.flags, self.protocol, self.algorithm,
dns.rdata._base64ify(self.key))
def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
flags = tok.get_uint16()
protocol = tok.get_uint8()
algorithm = dns.dnssec.algorithm_from_text(tok.get_string())
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)
b64 = ''.join(chunks)
key = b64.decode('base64_codec')
return cls(rdclass, rdtype, flags, protocol, algorithm, key)
from_text = classmethod(from_text)
def to_wire(self, file, compress = None, origin = None):
header = struct.pack("!HBB", self.flags, self.protocol, self.algorithm)
file.write(header)
file.write(self.key)
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
if rdlen < 4:
raise dns.exception.FormError
header = struct.unpack('!HBB', wire[current : current + 4])
current += 4
rdlen -= 4
key = wire[current : current + rdlen].unwrap()
return cls(rdclass, rdtype, header[0], header[1], header[2],
key)
from_wire = classmethod(from_wire)
def _cmp(self, other):
hs = struct.pack("!HBB", self.flags, self.protocol, self.algorithm)
ho = struct.pack("!HBB", other.flags, other.protocol, other.algorithm)
v = cmp(hs, ho)
if v == 0:
v = cmp(self.key, other.key)
return v
def flags_to_text_set(self):
"""Convert a DNSKEY flags value to set texts
@rtype: set([string])"""
return flags_to_text_set(self.flags)
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