4:5 #ˆl–ß=¿Jõ2ÛR‚ZP"¸Ëw꘴oÁ „™h_À¿?÷# 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 Names. @var root: The DNS root name. @type root: dns.name.Name object @var empty: The empty DNS name. @type empty: dns.name.Name object """ import cStringIO import struct import sys import copy if sys.hexversion >= 0x02030000: import encodings.idna import dns.exception import dns.wiredata NAMERELN_NONE = 0 NAMERELN_SUPERDOMAIN = 1 NAMERELN_SUBDOMAIN = 2 NAMERELN_EQUAL = 3 NAMERELN_COMMONANCESTOR = 4 class EmptyLabel(dns.exception.SyntaxError): """Raised if a label is empty.""" pass class BadEscape(dns.exception.SyntaxError): """Raised if an escaped code in a text format name is invalid.""" pass class BadPointer(dns.exception.FormError): """Raised if a compression pointer points forward instead of backward.""" pass class BadLabelType(dns.exception.FormError): """Raised if the label type of a wire format name is unknown.""" pass class NeedAbsoluteNameOrOrigin(dns.exception.DNSException): """Raised if an attempt is made to convert a non-absolute name to wire when there is also a non-absolute (or missing) origin.""" pass class NameTooLong(dns.exception.FormError): """Raised if a name is > 255 octets long.""" pass class LabelTooLong(dns.exception.SyntaxError): """Raised if a label is > 63 octets long.""" pass class AbsoluteConcatenation(dns.exception.DNSException): """Raised if an attempt is made to append anything other than the empty name to an absolute name.""" pass class NoParent(dns.exception.DNSException): """Raised if an attempt is made to get the parent of the root name or the empty name.""" pass _escaped = { '"' : True, '(' : True, ')' : True, '.' : True, ';' : True, '\\' : True, '@' : True, '$' : True } def _escapify(label, unicode_mode=False): """Escape the characters in label which need it. @param unicode_mode: escapify only special and whitespace (<= 0x20) characters @returns: the escaped string @rtype: string""" text = '' for c in label: if c in _escaped: text += '\\' + c elif ord(c) > 0x20 and ord(c) < 0x7F: text += c else: if unicode_mode and ord(c) >= 0x7F: text += c else: text += '\\%03d' % ord(c) return text def _validate_labels(labels): """Check for empty labels in the middle of a label sequence, labels that are too long, and for too many labels. @raises NameTooLong: the name as a whole is too long @raises LabelTooLong: an individual label is too long @raises EmptyLabel: a label is empty (i.e. the root label) and appears in a position other than the end of the label sequence""" l = len(labels) total = 0 i = -1 j = 0 for label in labels: ll = len(label) total += ll + 1 if ll > 63: raise LabelTooLong if i < 0 and label == '': i = j j += 1 if total > 255: raise NameTooLong if i >= 0 and i != l - 1: raise EmptyLabel class Name(object): """A DNS name. The dns.name.Name class represents a DNS name as a tuple of labels. Instances of the class are immutable.