1# Copyright (C) 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 string
18import struct
19
20import dns.exception
21import dns.rdata
22import dns.rdatatype
23
24class HIP(dns.rdata.Rdata):
25    """HIP record
26
27    @ivar hit: the host identity tag
28    @type hit: string
29    @ivar algorithm: the public key cryptographic algorithm
30    @type algorithm: int
31    @ivar key: the public key
32    @type key: string
33    @ivar servers: the rendezvous servers
34    @type servers: list of dns.name.Name objects
35    @see: RFC 5205"""
36
37    __slots__ = ['hit', 'algorithm', 'key', 'servers']
38
39    def __init__(self, rdclass, rdtype, hit, algorithm, key, servers):
40        super(HIP, self).__init__(rdclass, rdtype)
41        self.hit = hit
42        self.algorithm = algorithm
43        self.key = key
44        self.servers = servers
45
46    def to_text(self, origin=None, relativize=True, **kw):
47        hit = self.hit.encode('hex-codec')
48        key = self.key.encode('base64-codec').replace('\n', '')
49        text = ''
50        servers = []
51        for server in self.servers:
52            servers.append(str(server.choose_relativity(origin, relativize)))
53        if len(servers) > 0:
54            text += (' ' + ' '.join(servers))
55        return '%u %s %s%s' % (self.algorithm, hit, key, text)
56
57    def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
58        algorithm = tok.get_uint8()
59        hit = tok.get_string().decode('hex-codec')
60        if len(hit) > 255:
61            raise dns.exception.SyntaxError("HIT too long")
62        key = tok.get_string().decode('base64-codec')
63        servers = []
64        while 1:
65            token = tok.get()
66            if token.is_eol_or_eof():
67                break
68            server = dns.name.from_text(token.value, origin)
69            server.choose_relativity(origin, relativize)
70            servers.append(server)
71        return cls(rdclass, rdtype, hit, algorithm, key, servers)
72
73    from_text = classmethod(from_text)
74
75    def to_wire(self, file, compress = None, origin = None):
76        lh = len(self.hit)
77        lk = len(self.key)
78        file.write(struct.pack("!BBH", lh, self.algorithm, lk))
79        file.write(self.hit)
80        file.write(self.key)
81        for server in self.servers:
82            server.to_wire(file, None, origin)
83
84    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
85        (lh, algorithm, lk) = struct.unpack('!BBH',
86                                            wire[current : current + 4])
87        current += 4
88        rdlen -= 4
89        hit = wire[current : current + lh]
90        current += lh
91        rdlen -= lh
92        key = wire[current : current + lk]
93        current += lk
94        rdlen -= lk
95        servers = []
96        while rdlen > 0:
97            (server, cused) = dns.name.from_wire(wire[: current + rdlen],
98                                                 current)
99            current += cused
100            rdlen -= cused
101            if not origin is None:
102                server = server.relativize(origin)
103            servers.append(server)
104        return cls(rdclass, rdtype, hit, algorithm, key, servers)
105
106    from_wire = classmethod(from_wire)
107
108    def choose_relativity(self, origin = None, relativize = True):
109        servers = []
110        for server in self.servers:
111            server = server.choose_relativity(origin, relativize)
112            servers.append(server)
113        self.servers = servers
114
115    def _cmp(self, other):
116        b1 = cStringIO.StringIO()
117        lh = len(self.hit)
118        lk = len(self.key)
119        b1.write(struct.pack("!BBH", lh, self.algorithm, lk))
120        b1.write(self.hit)
121        b1.write(self.key)
122        b2 = cStringIO.StringIO()
123        lh = len(other.hit)
124        lk = len(other.key)
125        b2.write(struct.pack("!BBH", lh, other.algorithm, lk))
126        b2.write(other.hit)
127        b2.write(other.key)
128        v = cmp(b1.getvalue(), b2.getvalue())
129        if v != 0:
130            return v
131        ls = len(self.servers)
132        lo = len(other.servers)
133        count = min(ls, lo)
134        i = 0
135        while i < count:
136            v = cmp(self.servers[i], other.servers[i])
137            if v != 0:
138                return v
139            i += 1
140        return ls - lo
141