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✏️ Editing: NSEC3PARAM.py

# 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 binascii

import dns.exception
import dns.rdata
from dns._compat import text_type

class NSEC3PARAM(dns.rdata.Rdata):

"""NSEC3PARAM 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"""

__slots__ = ['algorithm', 'flags', 'iterations', 'salt']

def __init__(self, rdclass, rdtype, algorithm, flags, iterations, salt):
        super(NSEC3PARAM, self).__init__(rdclass, rdtype)
        self.algorithm = algorithm
        self.flags = flags
        self.iterations = iterations
        if isinstance(salt, text_type):
            self.salt = salt.encode()
        else:
            self.salt = salt

def to_text(self, origin=None, relativize=True, **kw):
        if self.salt == b'':
            salt = '-'
        else:
            salt = binascii.hexlify(self.salt).decode()
        return '%u %u %u %s' % (self.algorithm, self.flags, self.iterations,
                                salt)

@classmethod
    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 = binascii.unhexlify(salt.encode())
        tok.get_eol()
        return cls(rdclass, rdtype, algorithm, flags, iterations, salt)

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)

@classmethod
    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
        if rdlen != 0:
            raise dns.exception.FormError
        return cls(rdclass, rdtype, algorithm, flags, iterations, salt)

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