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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 base64
import cStringIO
import string
import struct
import dns.exception
import dns.rdata
import dns.rdatatype
b32_hex_to_normal = string.maketrans('0123456789ABCDEFGHIJKLMNOPQRSTUV',
'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567')
b32_normal_to_hex = string.maketrans('ABCDEFGHIJKLMNOPQRSTUVWXYZ234567',
'0123456789ABCDEFGHIJKLMNOPQRSTUV')
# hash algorithm constants
SHA1 = 1
# flag constants
OPTOUT = 1
class NSEC3(dns.rdata.Rdata):
"""NSEC3 record
@ivar algorithm: the hash algorithm number
@type algorithm: int
@ivar flags: the flags
@type flags: int
@ivar iterations: the number of iterations
@type iterations: int
@ivar salt: the salt
@type salt: string
@ivar next: the next name hash
@type next: string
@ivar windows: the windowed bitmap list
@type windows: list of (window number, string) tuples"""
__slots__ = ['algorithm', 'flags', 'iterations', 'salt', 'next', 'windows']
def __init__(self, rdclass, rdtype, algorithm, flags, iterations, salt,
next, windows):
super(NSEC3, self).__init__(rdclass, rdtype)
self.algorithm = algorithm
self.flags = flags
self.iterations = iterations
self.salt = salt
self.next = next
self.windows = windows
def to_text(self, origin=None, relativize=True, **kw):
next = base64.b32encode(self.next).translate(b32_normal_to_hex).lower()
if self.salt == '':
salt = '-'
else:
salt = self.salt.encode('hex-codec')
text = ''
for (window, bitmap) in self.windows:
bits = []
for i in xrange(0, len(bitmap)):
byte = ord(bitmap[i])
for j in xrange(0, 8):
if byte & (0x80 >> j):
bits.append(dns.rdatatype.to_text(window * 256 + \
i * 8 + j))
text += (' ' + ' '.join(bits))
return '%u %u %u %s %s%s' % (self.algorithm, self.flags, self.iterations,
salt, next, text)
def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
algorithm = tok.get_uint8()
flags = tok.get_uint8()
iterations = tok.get_uint16()
salt = tok.get_string()
if salt == '-':
salt = ''
else:
salt = salt.decode('hex-codec')
next = tok.get_string().upper().translate(b32_hex_to_normal)
next = base64.b32decode(next)
rdtypes = []
while 1:
token = tok.get().unescape()
if token.is_eol_or_eof():
break
nrdtype = dns.rdatatype.from_text(token.value)
if nrdtype == 0:
raise dns.exception.SyntaxError("NSEC3 with bit 0")
if nrdtype > 65535:
raise dns.exception.SyntaxError("NSEC3 with bit > 65535")
rdtypes.append(nrdtype)
rdtypes.sort()
window = 0
octets = 0
prior_rdtype = 0
bitmap = ['\0'] * 32
windows = []
for nrdtype in rdtypes:
if nrdtype == prior_rdtype:
continue
prior_rdtype = nrdtype
new_window = nrdtype // 256
if new_window != window:
windows.append((window, ''.join(bitmap[0:octets])))
bitmap = ['\0'] * 32
window = new_window
offset = nrdtype % 256
byte = offset // 8
bit = offset % 8
octets = byte + 1
bitmap[byte] = chr(ord(bitmap[byte]) | (0x80 >> bit))
windows.append((window, ''.join(bitmap[0:octets])))
return cls(rdclass, rdtype, algorithm, flags, iterations, salt, next, windows)
from_text = classmethod(from_text)
def to_wire(self, file, compress = None, origin = None):
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)
for (window, bitmap) in self.windows:
file.write(chr(window))
file.write(chr(len(bitmap)))
file.write(bitmap)
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
(algorithm, flags, iterations, slen) = struct.unpack('!BBHB',
wire[current : current + 5])
current += 5
rdlen -= 5
salt = wire[current : current + slen].unwrap()
current += slen
rdlen -= slen
(nlen, ) = struct.unpack('!B', wire[current])
current += 1
rdlen -= 1
next = wire[current : current + nlen].unwrap()
current += nlen
rdlen -= nlen
windows = []
while rdlen > 0:
if rdlen < 3:
raise dns.exception.FormError("NSEC3 too short")
window = ord(wire[current])
octets = ord(wire[current + 1])
if octets == 0 or octets > 32:
raise dns.exception.FormError("bad NSEC3 octets")
current += 2
rdlen -= 2
if rdlen < octets:
raise dns.exception.FormError("bad NSEC3 bitmap length")
bitmap = wire[current : current + octets].unwrap()
current += octets
rdlen -= octets
windows.append((window, bitmap))
return cls(rdclass, rdtype, algorithm, flags, iterations, salt, next, windows)
from_wire = classmethod(from_wire)
def _cmp(self, other):
b1 = cStringIO.StringIO()
self.to_wire(b1)
b2 = cStringIO.StringIO()
other.to_wire(b2)
return cmp(b1.getvalue(), b2.getvalue())
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