1# Copyright (C) 2003-2007, 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.dnssec
21import dns.rdata
22import dns.tokenizer
23
24_ctype_by_value = {
25    1 : 'PKIX',
26    2 : 'SPKI',
27    3 : 'PGP',
28    253 : 'URI',
29    254 : 'OID',
30    }
31
32_ctype_by_name = {
33    'PKIX' : 1,
34    'SPKI' : 2,
35    'PGP' : 3,
36    'URI' : 253,
37    'OID' : 254,
38    }
39
40def _ctype_from_text(what):
41    v = _ctype_by_name.get(what)
42    if not v is None:
43        return v
44    return int(what)
45
46def _ctype_to_text(what):
47    v = _ctype_by_value.get(what)
48    if not v is None:
49        return v
50    return str(what)
51
52class CERT(dns.rdata.Rdata):
53    """CERT record
54
55    @ivar certificate_type: certificate type
56    @type certificate_type: int
57    @ivar key_tag: key tag
58    @type key_tag: int
59    @ivar algorithm: algorithm
60    @type algorithm: int
61    @ivar certificate: the certificate or CRL
62    @type certificate: string
63    @see: RFC 2538"""
64
65    __slots__ = ['certificate_type', 'key_tag', 'algorithm', 'certificate']
66
67    def __init__(self, rdclass, rdtype, certificate_type, key_tag, algorithm,
68                 certificate):
69        super(CERT, self).__init__(rdclass, rdtype)
70        self.certificate_type = certificate_type
71        self.key_tag = key_tag
72        self.algorithm = algorithm
73        self.certificate = certificate
74
75    def to_text(self, origin=None, relativize=True, **kw):
76        certificate_type = _ctype_to_text(self.certificate_type)
77        return "%s %d %s %s" % (certificate_type, self.key_tag,
78                                dns.dnssec.algorithm_to_text(self.algorithm),
79                                dns.rdata._base64ify(self.certificate))
80
81    def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
82        certificate_type = _ctype_from_text(tok.get_string())
83        key_tag = tok.get_uint16()
84        algorithm = dns.dnssec.algorithm_from_text(tok.get_string())
85        if algorithm < 0 or algorithm > 255:
86            raise dns.exception.SyntaxError("bad algorithm type")
87        chunks = []
88        while 1:
89            t = tok.get().unescape()
90            if t.is_eol_or_eof():
91                break
92            if not t.is_identifier():
93                raise dns.exception.SyntaxError
94            chunks.append(t.value)
95        b64 = ''.join(chunks)
96        certificate = b64.decode('base64_codec')
97        return cls(rdclass, rdtype, certificate_type, key_tag,
98                   algorithm, certificate)
99
100    from_text = classmethod(from_text)
101
102    def to_wire(self, file, compress = None, origin = None):
103        prefix = struct.pack("!HHB", self.certificate_type, self.key_tag,
104                             self.algorithm)
105        file.write(prefix)
106        file.write(self.certificate)
107
108    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
109        prefix = wire[current : current + 5]
110        current += 5
111        rdlen -= 5
112        if rdlen < 0:
113            raise dns.exception.FormError
114        (certificate_type, key_tag, algorithm) = struct.unpack("!HHB", prefix)
115        certificate = wire[current : current + rdlen]
116        return cls(rdclass, rdtype, certificate_type, key_tag, algorithm,
117                   certificate)
118
119    from_wire = classmethod(from_wire)
120
121    def _cmp(self, other):
122        f = cStringIO.StringIO()
123        self.to_wire(f)
124        wire1 = f.getvalue()
125        f.seek(0)
126        f.truncate()
127        other.to_wire(f)
128        wire2 = f.getvalue()
129        f.close()
130
131        return cmp(wire1, wire2)
132