1# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
2
3# Copyright (C) 2001-2017 Nominum, Inc.
4#
5# Permission to use, copy, modify, and distribute this software and its
6# documentation for any purpose with or without fee is hereby granted,
7# provided that the above copyright notice and this permission notice
8# appear in all copies.
9#
10# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
11# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
13# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
16# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17
18import struct
19
20import dns.edns
21import dns.exception
22import dns.rdata
23
24
25class OPT(dns.rdata.Rdata):
26
27    """OPT record"""
28
29    __slots__ = ['options']
30
31    def __init__(self, rdclass, rdtype, options):
32        """Initialize an OPT rdata.
33
34        *rdclass*, an ``int`` is the rdataclass of the Rdata,
35        which is also the payload size.
36
37        *rdtype*, an ``int`` is the rdatatype of the Rdata.
38
39        *options*, a tuple of ``bytes``
40        """
41
42        super().__init__(rdclass, rdtype)
43        object.__setattr__(self, 'options', dns.rdata._constify(options))
44
45    def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
46        for opt in self.options:
47            owire = opt.to_wire()
48            file.write(struct.pack("!HH", opt.otype, len(owire)))
49            file.write(owire)
50
51    def to_text(self, origin=None, relativize=True, **kw):
52        return ' '.join(opt.to_text() for opt in self.options)
53
54    @classmethod
55    def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
56        options = []
57        while parser.remaining() > 0:
58            (otype, olen) = parser.get_struct('!HH')
59            with parser.restrict_to(olen):
60                opt = dns.edns.option_from_wire_parser(otype, parser)
61            options.append(opt)
62        return cls(rdclass, rdtype, options)
63
64    @property
65    def payload(self):
66        "payload size"
67        return self.rdclass
68