1# Copyright (C) 2004-2007, 2009, 2010 Nominum, Inc.
2#
3# Permission to use, copy, modify, and distribute this software and its
4# documentation for any purpose with or without fee is hereby granted,
5# provided that the above copyright notice and this permission notice
6# appear in all copies.
7#
8# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
9# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
11# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
14# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15
16import cStringIO
17import struct
18
19import dns.exception
20import dns.rdata
21
22class NSEC3PARAM(dns.rdata.Rdata):
23    """NSEC3PARAM record
24
25    @ivar algorithm: the hash algorithm number
26    @type algorithm: int
27    @ivar flags: the flags
28    @type flags: int
29    @ivar iterations: the number of iterations
30    @type iterations: int
31    @ivar salt: the salt
32    @type salt: string"""
33
34    __slots__ = ['algorithm', 'flags', 'iterations', 'salt']
35
36    def __init__(self, rdclass, rdtype, algorithm, flags, iterations, salt):
37        super(NSEC3PARAM, self).__init__(rdclass, rdtype)
38        self.algorithm = algorithm
39        self.flags = flags
40        self.iterations = iterations
41        self.salt = salt
42
43    def to_text(self, origin=None, relativize=True, **kw):
44        if self.salt == '':
45            salt = '-'
46        else:
47            salt = self.salt.encode('hex-codec')
48        return '%u %u %u %s' % (self.algorithm, self.flags, self.iterations, salt)
49
50    def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
51        algorithm = tok.get_uint8()
52        flags = tok.get_uint8()
53        iterations = tok.get_uint16()
54        salt = tok.get_string()
55        if salt == '-':
56            salt = ''
57        else:
58            salt = salt.decode('hex-codec')
59        return cls(rdclass, rdtype, algorithm, flags, iterations, salt)
60
61    from_text = classmethod(from_text)
62
63    def to_wire(self, file, compress = None, origin = None):
64        l = len(self.salt)
65        file.write(struct.pack("!BBHB", self.algorithm, self.flags,
66                               self.iterations, l))
67        file.write(self.salt)
68
69    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
70        (algorithm, flags, iterations, slen) = struct.unpack('!BBHB',
71                                                             wire[current : current + 5])
72        current += 5
73        rdlen -= 5
74        salt = wire[current : current + slen]
75        current += slen
76        rdlen -= slen
77        if rdlen != 0:
78            raise dns.exception.FormError
79        return cls(rdclass, rdtype, algorithm, flags, iterations, salt)
80
81    from_wire = classmethod(from_wire)
82
83    def _cmp(self, other):
84        b1 = cStringIO.StringIO()
85        self.to_wire(b1)
86        b2 = cStringIO.StringIO()
87        other.to_wire(b2)
88        return cmp(b1.getvalue(), b2.getvalue())
89