# Copyright (C) 2003-2007, 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 dns.exception
import dns.rdata
import dns.tokenizer
class CAA(dns.rdata.Rdata):
"""CAA (Certification Authority Authorization) record
@ivar flags: the flags
@type flags: int
@ivar tag: the tag
@type tag: string
@ivar value: the value
@type value: string
@see: RFC 6844"""
__slots__ = ['flags', 'tag', 'value']
def __init__(self, rdclass, rdtype, flags, tag, value):
super(CAA, self).__init__(rdclass, rdtype)
self.flags = flags
self.tag = tag
self.value = value
def to_text(self, origin=None, relativize=True, **kw):
return '%u %s "%s"' % (self.flags,
dns.rdata._escapify(self.tag),
dns.rdata._escapify(self.value))
@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
flags = tok.get_uint8()
tag = tok.get_string().encode()
if len(tag) > 255:
raise dns.exception.SyntaxError("tag too long")
if not tag.isalnum():
raise dns.exception.SyntaxError("tag is not alphanumeric")
value = tok.get_string().encode()
return cls(rdclass, rdtype, flags, tag, value)
def to_wire(self, file, compress=None, origin=None):
file.write(struct.pack('!B', self.flags))
l = len(self.tag)
assert l < 256
file.write(struct.pack('!B', l))
file.write(self.tag)
file.write(self.value)
@classmethod
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
(flags, l) = struct.unpack('!BB', wire[current: current + 2])
current += 2
tag = wire[current: current + l]
value = wire[current + l:current + rdlen - 2]
return cls(rdclass, rdtype, flags, tag, value)
