Package dns :: Package rdtypes :: Module dnskeybase
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Source Code for Module dns.rdtypes.dnskeybase

  1  # Copyright (C) 2004-2007, 2009-2011 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   
 16  import base64 
 17  import struct 
 18   
 19  import dns.exception 
 20  import dns.dnssec 
 21  import dns.rdata 
 22   
 23  # wildcard import 
 24  __all__ = ["SEP", "REVOKE", "ZONE", 
 25             "flags_to_text_set", "flags_from_text_set"] 
 26   
 27  # flag constants 
 28  SEP = 0x0001 
 29  REVOKE = 0x0080 
 30  ZONE = 0x0100 
 31   
 32  _flag_by_text = { 
 33      'SEP': SEP, 
 34      'REVOKE': REVOKE, 
 35      'ZONE': ZONE 
 36  } 
 37   
 38  # We construct the inverse mapping programmatically to ensure that we 
 39  # cannot make any mistakes (e.g. omissions, cut-and-paste errors) that 
 40  # would cause the mapping not to be true inverse. 
 41  _flag_by_value = dict((y, x) for x, y in _flag_by_text.items()) 
42 43 44 -def flags_to_text_set(flags):
45 """Convert a DNSKEY flags value to set texts 46 @rtype: set([string])""" 47 48 flags_set = set() 49 mask = 0x1 50 while mask <= 0x8000: 51 if flags & mask: 52 text = _flag_by_value.get(mask) 53 if not text: 54 text = hex(mask) 55 flags_set.add(text) 56 mask <<= 1 57 return flags_set
58
59 60 -def flags_from_text_set(texts_set):
61 """Convert set of DNSKEY flag mnemonic texts to DNSKEY flag value 62 @rtype: int""" 63 64 flags = 0 65 for text in texts_set: 66 try: 67 flags += _flag_by_text[text] 68 except KeyError: 69 raise NotImplementedError( 70 "DNSKEY flag '%s' is not supported" % text) 71 return flags
72
73 74 -class DNSKEYBase(dns.rdata.Rdata):
75 76 """Base class for rdata that is like a DNSKEY record 77 78 @ivar flags: the key flags 79 @type flags: int 80 @ivar protocol: the protocol for which this key may be used 81 @type protocol: int 82 @ivar algorithm: the algorithm used for the key 83 @type algorithm: int 84 @ivar key: the public key 85 @type key: string""" 86 87 __slots__ = ['flags', 'protocol', 'algorithm', 'key'] 88
89 - def __init__(self, rdclass, rdtype, flags, protocol, algorithm, key):
90 super(DNSKEYBase, self).__init__(rdclass, rdtype) 91 self.flags = flags 92 self.protocol = protocol 93 self.algorithm = algorithm 94 self.key = key
95
96 - def to_text(self, origin=None, relativize=True, **kw):
97 return '%d %d %d %s' % (self.flags, self.protocol, self.algorithm, 98 dns.rdata._base64ify(self.key))
99 100 @classmethod
101 - def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
102 flags = tok.get_uint16() 103 protocol = tok.get_uint8() 104 algorithm = dns.dnssec.algorithm_from_text(tok.get_string()) 105 chunks = [] 106 while 1: 107 t = tok.get().unescape() 108 if t.is_eol_or_eof(): 109 break 110 if not t.is_identifier(): 111 raise dns.exception.SyntaxError 112 chunks.append(t.value.encode()) 113 b64 = b''.join(chunks) 114 key = base64.b64decode(b64) 115 return cls(rdclass, rdtype, flags, protocol, algorithm, key)
116
117 - def to_wire(self, file, compress=None, origin=None):
118 header = struct.pack("!HBB", self.flags, self.protocol, self.algorithm) 119 file.write(header) 120 file.write(self.key)
121 122 @classmethod
123 - def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
124 if rdlen < 4: 125 raise dns.exception.FormError 126 header = struct.unpack('!HBB', wire[current: current + 4]) 127 current += 4 128 rdlen -= 4 129 key = wire[current: current + rdlen].unwrap() 130 return cls(rdclass, rdtype, header[0], header[1], header[2], 131 key)
132
133 - def flags_to_text_set(self):
134 """Convert a DNSKEY flags value to set texts 135 @rtype: set([string])""" 136 return flags_to_text_set(self.flags)
137