# Copyright (C) 2001-2007, 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.
"""DNS Rdata Types.
@var _by_text: The rdata type textual name to value mapping
@type _by_text: dict
@var _by_value: The rdata type value to textual name mapping
@type _by_value: dict
@var _metatypes: If an rdatatype is a metatype, there will be a mapping
whose key is the rdatatype value and whose value is True in this dictionary.
@type _metatypes: dict
@var _singletons: If an rdatatype is a singleton, there will be a mapping
whose key is the rdatatype value and whose value is True in this dictionary.
@type _singletons: dict"""
import re
import dns.exception
NONE = 0
A = 1
NS = 2
MD = 3
MF = 4
CNAME = 5
SOA = 6
MB = 7
MG = 8
MR = 9
NULL = 10
WKS = 11
PTR = 12
HINFO = 13
MINFO = 14
MX = 15
TXT = 16
RP = 17
AFSDB = 18
X25 = 19
ISDN = 20
RT = 21
NSAP = 22
NSAP_PTR = 23
SIG = 24
KEY = 25
PX = 26
GPOS = 27
AAAA = 28
LOC = 29
NXT = 30
SRV = 33
NAPTR = 35
KX = 36
CERT = 37
A6 = 38
DNAME = 39
OPT = 41
APL = 42
DS = 43
SSHFP = 44
IPSECKEY = 45
RRSIG = 46
NSEC = 47
DNSKEY = 48
DHCID = 49
NSEC3 = 50
NSEC3PARAM = 51
TLSA = 52
HIP = 55
CDS = 59
CDNSKEY = 60
CSYNC = 62
SPF = 99
UNSPEC = 103
EUI48 = 108
EUI64 = 109
TKEY = 249
TSIG = 250
IXFR = 251
AXFR = 252
MAILB = 253
MAILA = 254
ANY = 255
URI = 256
CAA = 257
AVC = 258
TA = 32768
DLV = 32769
_by_text = {
'NONE': NONE,
'A': A,
'NS': NS,
'MD': MD,
'MF': MF,
'CNAME': CNAME,
'SOA': SOA,
'MB': MB,
'MG': MG,
'MR': MR,
'NULL': NULL,
'WKS': WKS,
'PTR': PTR,
'HINFO': HINFO,
'MINFO': MINFO,
'MX': MX,
'TXT': TXT,
'RP': RP,
'AFSDB': AFSDB,
'X25': X25,
'ISDN': ISDN,
'RT': RT,
'NSAP': NSAP,
'NSAP-PTR': NSAP_PTR,
'SIG': SIG,
'KEY': KEY,
'PX': PX,
'GPOS': GPOS,
'AAAA': AAAA,
'LOC': LOC,
'NXT': NXT,
'SRV': SRV,
'NAPTR': NAPTR,
'KX': KX,
'CERT': CERT,
'A6': A6,
'DNAME': DNAME,
'OPT': OPT,
'APL': APL,
'DS': DS,
'SSHFP': SSHFP,
'IPSECKEY': IPSECKEY,
'RRSIG': RRSIG,
'NSEC': NSEC,
'DNSKEY': DNSKEY,
'DHCID': DHCID,
'NSEC3': NSEC3,
'NSEC3PARAM': NSEC3PARAM,
'TLSA': TLSA,
'HIP': HIP,
'CDS': CDS,
'CDNSKEY': CDNSKEY,
'CSYNC': CSYNC,
'SPF': SPF,
'UNSPEC': UNSPEC,
'EUI48': EUI48,
'EUI64': EUI64,
'TKEY': TKEY,
'TSIG': TSIG,
'IXFR': IXFR,
'AXFR': AXFR,
'MAILB': MAILB,
'MAILA': MAILA,
'ANY': ANY,
'URI': URI,
'CAA': CAA,
'AVC': AVC,
'TA': TA,
'DLV': DLV,
}
# We construct the inverse mapping programmatically to ensure that we
# cannot make any mistakes (e.g. omissions, cut-and-paste errors) that
# would cause the mapping not to be true inverse.
_by_value = dict((y, x) for x, y in _by_text.items())
_metatypes = {
OPT: True
}
_singletons = {
SOA: True,
NXT: True,
DNAME: True,
NSEC: True,
# CNAME is technically a singleton, but we allow multiple CNAMEs.
}
_unknown_type_pattern = re.compile('TYPE([0-9]+)$', re.I)
class UnknownRdatatype(dns.exception.DNSException):
"""DNS resource record type is unknown."""
def from_text(text):
"""Convert text into a DNS rdata type value.
@param text: the text
@type text: string
@raises dns.rdatatype.UnknownRdatatype: the type is unknown
@raises ValueError: the rdata type value is not >= 0 and <= 65535
@rtype: int"""
value = _by_text.get(text.upper())
if value is None:
match = _unknown_type_pattern.match(text)
if match is None:
raise UnknownRdatatype
value = int(match.group(1))
if value < 0 or value > 65535:
raise ValueError("type must be between >= 0 and <= 65535")
return value
def to_text(value):
"""Convert a DNS rdata type to text.
@param value: the rdata type value
@type value: int
@raises ValueError: the rdata type value is not >= 0 and <= 65535
@rtype: string"""
if value < 0 or value > 65535:
raise ValueError("type must be between >= 0 and <= 65535")
text = _by_value.get(value)
if text is None:
text = 'TYPE' + repr(value)
return text
def is_metatype(rdtype):
"""True if the type is a metatype.
@param rdtype: the type
@type rdtype: int
@rtype: bool"""
if rdtype >= TKEY and rdtype <= ANY or rdtype in _metatypes:
return True
return False
def is_singleton(rdtype):
"""True if the type is a singleton.
@param rdtype: the type
@type rdtype: int
@rtype: bool"""
if rdtype in _singletons:
return True
return False
