From 4bbc3ff037026c72f3249f59c1b5af69a6ad6d69 Mon Sep 17 00:00:00 2001 From: Jelmer Vernooij Date: Mon, 29 Mar 2010 16:08:11 +0200 Subject: s4-python: Move dnspython to lib/, like the other Python modules This also avoids it from being installed if it's already present on the system. --- lib/dnspython/dns/rdataclass.py | 114 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 lib/dnspython/dns/rdataclass.py (limited to 'lib/dnspython/dns/rdataclass.py') diff --git a/lib/dnspython/dns/rdataclass.py b/lib/dnspython/dns/rdataclass.py new file mode 100644 index 0000000000..887fd1ad6b --- /dev/null +++ b/lib/dnspython/dns/rdataclass.py @@ -0,0 +1,114 @@ +# Copyright (C) 2001-2007, 2009, 2010 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 Classes. + +@var _by_text: The rdata class textual name to value mapping +@type _by_text: dict +@var _by_value: The rdata class value to textual name mapping +@type _by_value: dict +@var _metaclasses: If an rdataclass is a metaclass, there will be a mapping +whose key is the rdatatype value and whose value is True in this dictionary. +@type _metaclasses: dict""" + +import re + +import dns.exception + +RESERVED0 = 0 +IN = 1 +CH = 3 +HS = 4 +NONE = 254 +ANY = 255 + +_by_text = { + 'RESERVED0' : RESERVED0, + 'IN' : IN, + 'CH' : CH, + 'HS' : HS, + 'NONE' : NONE, + 'ANY' : ANY + } + +# 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.iteritems()]) + +# Now that we've built the inverse map, we can add class aliases to +# the _by_text mapping. + +_by_text.update({ + 'INTERNET' : IN, + 'CHAOS' : CH, + 'HESIOD' : HS + }) + +_metaclasses = { + NONE : True, + ANY : True + } + +_unknown_class_pattern = re.compile('CLASS([0-9]+)$', re.I); + +class UnknownRdataclass(dns.exception.DNSException): + """Raised when a class is unknown.""" + pass + +def from_text(text): + """Convert text into a DNS rdata class value. + @param text: the text + @type text: string + @rtype: int + @raises dns.rdataclass.UnknownRdataClass: the class is unknown + @raises ValueError: the rdata class value is not >= 0 and <= 65535 + """ + + value = _by_text.get(text.upper()) + if value is None: + match = _unknown_class_pattern.match(text) + if match == None: + raise UnknownRdataclass + value = int(match.group(1)) + if value < 0 or value > 65535: + raise ValueError("class must be between >= 0 and <= 65535") + return value + +def to_text(value): + """Convert a DNS rdata class to text. + @param value: the rdata class value + @type value: int + @rtype: string + @raises ValueError: the rdata class value is not >= 0 and <= 65535 + """ + + if value < 0 or value > 65535: + raise ValueError("class must be between >= 0 and <= 65535") + text = _by_value.get(value) + if text is None: + text = 'CLASS' + `value` + return text + +def is_metaclass(rdclass): + """True if the class is a metaclass. + @param rdclass: the rdata class + @type rdclass: int + @rtype: bool""" + + if _metaclasses.has_key(rdclass): + return True + return False -- cgit