lib/dnspython/dns/rdatatype.py

   1 # Copyright (C) 2001-2007, 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 """DNS Rdata Types.
  17
  18 @var _by_text: The rdata type textual name to value mapping
  19 @type _by_text: dict
  20 @var _by_value: The rdata type value to textual name mapping
  21 @type _by_value: dict
  22 @var _metatypes: If an rdatatype is a metatype, there will be a mapping
  23 whose key is the rdatatype value and whose value is True in this dictionary.
  24 @type _metatypes: dict
  25 @var _singletons: If an rdatatype is a singleton, there will be a mapping
  26 whose key is the rdatatype value and whose value is True in this dictionary.
  27 @type _singletons: dict"""
  28
  29 import re
  30
  31 import dns.exception
  32
  33 NONE = 0
  34 A = 1
  35 NS = 2
  36 MD = 3
  37 MF = 4
  38 CNAME = 5
  39 SOA = 6
  40 MB = 7
  41 MG = 8
  42 MR = 9
  43 NULL = 10
  44 WKS = 11
  45 PTR = 12
  46 HINFO = 13
  47 MINFO = 14
  48 MX = 15
  49 TXT = 16
  50 RP = 17
  51 AFSDB = 18
  52 X25 = 19
  53 ISDN = 20
  54 RT = 21
  55 NSAP = 22
  56 NSAP_PTR = 23
  57 SIG = 24
  58 KEY = 25
  59 PX = 26
  60 GPOS = 27
  61 AAAA = 28
  62 LOC = 29
  63 NXT = 30
  64 SRV = 33
  65 NAPTR = 35
  66 KX = 36
  67 CERT = 37
  68 A6 = 38
  69 DNAME = 39
  70 OPT = 41
  71 APL = 42
  72 DS = 43
  73 SSHFP = 44
  74 IPSECKEY = 45
  75 RRSIG = 46
  76 NSEC = 47
  77 DNSKEY = 48
  78 DHCID = 49
  79 NSEC3 = 50
  80 NSEC3PARAM = 51
  81 HIP = 55
  82 SPF = 99
  83 UNSPEC = 103
  84 TKEY = 249
  85 TSIG = 250
  86 IXFR = 251
  87 AXFR = 252
  88 MAILB = 253
  89 MAILA = 254
  90 ANY = 255
  91 TA = 32768
  92 DLV = 32769
  93
  94 _by_text = {
  95     'NONE' : NONE,
  96     'A' : A,
  97     'NS' : NS,
  98     'MD' : MD,
  99     'MF' : MF,
 100     'CNAME' : CNAME,
 101     'SOA' : SOA,
 102     'MB' : MB,
 103     'MG' : MG,
 104     'MR' : MR,
 105     'NULL' : NULL,
 106     'WKS' : WKS,
 107     'PTR' : PTR,
 108     'HINFO' : HINFO,
 109     'MINFO' : MINFO,
 110     'MX' : MX,
 111     'TXT' : TXT,
 112     'RP' : RP,
 113     'AFSDB' : AFSDB,
 114     'X25' : X25,
 115     'ISDN' : ISDN,
 116     'RT' : RT,
 117     'NSAP' : NSAP,
 118     'NSAP-PTR' : NSAP_PTR,
 119     'SIG' : SIG,
 120     'KEY' : KEY,
 121     'PX' : PX,
 122     'GPOS' : GPOS,
 123     'AAAA' : AAAA,
 124     'LOC' : LOC,
 125     'NXT' : NXT,
 126     'SRV' : SRV,
 127     'NAPTR' : NAPTR,
 128     'KX' : KX,
 129     'CERT' : CERT,
 130     'A6' : A6,
 131     'DNAME' : DNAME,
 132     'OPT' : OPT,
 133     'APL' : APL,
 134     'DS' : DS,
 135     'SSHFP' : SSHFP,
 136     'IPSECKEY' : IPSECKEY,
 137     'RRSIG' : RRSIG,
 138     'NSEC' : NSEC,
 139     'DNSKEY' : DNSKEY,
 140     'DHCID' : DHCID,
 141     'NSEC3' : NSEC3,
 142     'NSEC3PARAM' : NSEC3PARAM,
 143     'HIP' : HIP,
 144     'SPF' : SPF,
 145     'UNSPEC' : UNSPEC,
 146     'TKEY' : TKEY,
 147     'TSIG' : TSIG,
 148     'IXFR' : IXFR,
 149     'AXFR' : AXFR,
 150     'MAILB' : MAILB,
 151     'MAILA' : MAILA,
 152     'ANY' : ANY,
 153     'TA' : TA,
 154     'DLV' : DLV,
 155     }
 156
 157 # We construct the inverse mapping programmatically to ensure that we
 158 # cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
 159 # would cause the mapping not to be true inverse.
 160
 161 _by_value = dict([(y, x) for x, y in _by_text.iteritems()])
 162
 163
 164 _metatypes = {
 165     OPT : True
 166     }
 167
 168 _singletons = {
 169     SOA : True,
 170     NXT : True,
 171     DNAME : True,
 172     NSEC : True,
 173     # CNAME is technically a singleton, but we allow multiple CNAMEs.
 174     }
 175
 176 _unknown_type_pattern = re.compile('TYPE([0-9]+)$', re.I);
 177
 178 class UnknownRdatatype(dns.exception.DNSException):
 179     """Raised if a type is unknown."""
 180     pass
 181
 182 def from_text(text):
 183     """Convert text into a DNS rdata type value.
 184     @param text: the text
 185     @type text: string
 186     @raises dns.rdatatype.UnknownRdatatype: the type is unknown
 187     @raises ValueError: the rdata type value is not >= 0 and <= 65535
 188     @rtype: int"""
 189
 190     value = _by_text.get(text.upper())
 191     if value is None:
 192         match = _unknown_type_pattern.match(text)
 193         if match == None:
 194             raise UnknownRdatatype
 195         value = int(match.group(1))
 196         if value < 0 or value > 65535:
 197             raise ValueError("type must be between >= 0 and <= 65535")
 198     return value
 199
 200 def to_text(value):
 201     """Convert a DNS rdata type to text.
 202     @param value: the rdata type value
 203     @type value: int
 204     @raises ValueError: the rdata type value is not >= 0 and <= 65535
 205     @rtype: string"""
 206
 207     if value < 0 or value > 65535:
 208         raise ValueError("type must be between >= 0 and <= 65535")
 209     text = _by_value.get(value)
 210     if text is None:
 211         text = 'TYPE' + `value`
 212     return text
 213
 214 def is_metatype(rdtype):
 215     """True if the type is a metatype.
 216     @param rdtype: the type
 217     @type rdtype: int
 218     @rtype: bool"""
 219
 220     if rdtype >= TKEY and rdtype <= ANY or _metatypes.has_key(rdtype):
 221         return True
 222     return False
 223
 224 def is_singleton(rdtype):
 225     """True if the type is a singleton.
 226     @param rdtype: the type
 227     @type rdtype: int
 228     @rtype: bool"""
 229
 230     if _singletons.has_key(rdtype):
 231         return True
 232     return False