lib/dnspython/dns/dnssec.py

   1 # Copyright (C) 2003-2007, 2009 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 """Common DNSSEC-related functions and constants."""
  17
  18 RSAMD5 = 1
  19 DH = 2
  20 DSA = 3
  21 ECC = 4
  22 RSASHA1 = 5
  23 DSANSEC3SHA1 = 6
  24 RSASHA1NSEC3SHA1 = 7
  25 RSASHA256 = 8
  26 RSASHA512 = 10
  27 INDIRECT = 252
  28 PRIVATEDNS = 253
  29 PRIVATEOID = 254
  30
  31 _algorithm_by_text = {
  32     'RSAMD5' : RSAMD5,
  33     'DH' : DH,
  34     'DSA' : DSA,
  35     'ECC' : ECC,
  36     'RSASHA1' : RSASHA1,
  37     'DSANSEC3SHA1' : DSANSEC3SHA1,
  38     'RSASHA1NSEC3SHA1' : RSASHA1NSEC3SHA1,
  39     'RSASHA256' : RSASHA256,
  40     'RSASHA512' : RSASHA512,
  41     'INDIRECT' : INDIRECT,
  42     'PRIVATEDNS' : PRIVATEDNS,
  43     'PRIVATEOID' : PRIVATEOID,
  44     }
  45
  46 # We construct the inverse mapping programmatically to ensure that we
  47 # cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
  48 # would cause the mapping not to be true inverse.
  49
  50 _algorithm_by_value = dict([(y, x) for x, y in _algorithm_by_text.iteritems()])
  51
  52 class UnknownAlgorithm(Exception):
  53     """Raised if an algorithm is unknown."""
  54     pass
  55
  56 def algorithm_from_text(text):
  57     """Convert text into a DNSSEC algorithm value
  58     @rtype: int"""
  59
  60     value = _algorithm_by_text.get(text.upper())
  61     if value is None:
  62         value = int(text)
  63     return value
  64
  65 def algorithm_to_text(value):
  66     """Convert a DNSSEC algorithm value to text
  67     @rtype: string"""
  68
  69     text = _algorithm_by_value.get(value)
  70     if text is None:
  71         text = str(value)
  72     return text