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✏️ Editing: TLSA.py

# Copyright (C) 2005-2007, 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 binascii

import dns.rdata
import dns.rdatatype

class TLSA(dns.rdata.Rdata):

"""TLSA record

@ivar usage: The certificate usage
    @type usage: int
    @ivar selector: The selector field
    @type selector: int
    @ivar mtype: The 'matching type' field
    @type mtype: int
    @ivar cert: The 'Certificate Association Data' field
    @type cert: string
    @see: RFC 6698"""

__slots__ = ['usage', 'selector', 'mtype', 'cert']

def __init__(self, rdclass, rdtype, usage, selector,
                 mtype, cert):
        super(TLSA, self).__init__(rdclass, rdtype)
        self.usage = usage
        self.selector = selector
        self.mtype = mtype
        self.cert = cert

def to_text(self, origin=None, relativize=True, **kw):
        return '%d %d %d %s' % (self.usage,
                                self.selector,
                                self.mtype,
                                dns.rdata._hexify(self.cert,
                                                  chunksize=128))

@classmethod
    def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
        usage = tok.get_uint8()
        selector = tok.get_uint8()
        mtype = tok.get_uint8()
        cert_chunks = []
        while 1:
            t = tok.get().unescape()
            if t.is_eol_or_eof():
                break
            if not t.is_identifier():
                raise dns.exception.SyntaxError
            cert_chunks.append(t.value.encode())
        cert = b''.join(cert_chunks)
        cert = binascii.unhexlify(cert)
        return cls(rdclass, rdtype, usage, selector, mtype, cert)

def to_wire(self, file, compress=None, origin=None):
        header = struct.pack("!BBB", self.usage, self.selector, self.mtype)
        file.write(header)
        file.write(self.cert)

@classmethod
    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
        header = struct.unpack("!BBB", wire[current: current + 3])
        current += 3
        rdlen -= 3
        cert = wire[current: current + rdlen].unwrap()
        return cls(rdclass, rdtype, header[0], header[1], header[2], cert)

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