diff options
Diffstat (limited to 'lib/dnspython/dns/rdtypes/ANY/NSEC.py')
-rw-r--r-- | lib/dnspython/dns/rdtypes/ANY/NSEC.py | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/lib/dnspython/dns/rdtypes/ANY/NSEC.py b/lib/dnspython/dns/rdtypes/ANY/NSEC.py new file mode 100644 index 0000000000..72859ce108 --- /dev/null +++ b/lib/dnspython/dns/rdtypes/ANY/NSEC.py @@ -0,0 +1,141 @@ +# Copyright (C) 2004-2007, 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. + +import cStringIO + +import dns.exception +import dns.rdata +import dns.rdatatype +import dns.name + +class NSEC(dns.rdata.Rdata): + """NSEC record + + @ivar next: the next name + @type next: dns.name.Name object + @ivar windows: the windowed bitmap list + @type windows: list of (window number, string) tuples""" + + __slots__ = ['next', 'windows'] + + def __init__(self, rdclass, rdtype, next, windows): + super(NSEC, self).__init__(rdclass, rdtype) + self.next = next + self.windows = windows + + def to_text(self, origin=None, relativize=True, **kw): + next = self.next.choose_relativity(origin, relativize) + text = '' + for (window, bitmap) in self.windows: + bits = [] + for i in xrange(0, len(bitmap)): + byte = ord(bitmap[i]) + for j in xrange(0, 8): + if byte & (0x80 >> j): + bits.append(dns.rdatatype.to_text(window * 256 + \ + i * 8 + j)) + text += (' ' + ' '.join(bits)) + return '%s%s' % (next, text) + + def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True): + next = tok.get_name() + next = next.choose_relativity(origin, relativize) + rdtypes = [] + while 1: + token = tok.get().unescape() + if token.is_eol_or_eof(): + break + nrdtype = dns.rdatatype.from_text(token.value) + if nrdtype == 0: + raise dns.exception.SyntaxError("NSEC with bit 0") + if nrdtype > 65535: + raise dns.exception.SyntaxError("NSEC with bit > 65535") + rdtypes.append(nrdtype) + rdtypes.sort() + window = 0 + octets = 0 + prior_rdtype = 0 + bitmap = ['\0'] * 32 + windows = [] + for nrdtype in rdtypes: + if nrdtype == prior_rdtype: + continue + prior_rdtype = nrdtype + new_window = nrdtype // 256 + if new_window != window: + windows.append((window, ''.join(bitmap[0:octets]))) + bitmap = ['\0'] * 32 + window = new_window + offset = nrdtype % 256 + byte = offset / 8 + bit = offset % 8 + octets = byte + 1 + bitmap[byte] = chr(ord(bitmap[byte]) | (0x80 >> bit)) + windows.append((window, ''.join(bitmap[0:octets]))) + return cls(rdclass, rdtype, next, windows) + + from_text = classmethod(from_text) + + def to_wire(self, file, compress = None, origin = None): + self.next.to_wire(file, None, origin) + for (window, bitmap) in self.windows: + file.write(chr(window)) + file.write(chr(len(bitmap))) + file.write(bitmap) + + def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None): + (next, cused) = dns.name.from_wire(wire[: current + rdlen], current) + current += cused + rdlen -= cused + windows = [] + while rdlen > 0: + if rdlen < 3: + raise dns.exception.FormError("NSEC too short") + window = ord(wire[current]) + octets = ord(wire[current + 1]) + if octets == 0 or octets > 32: + raise dns.exception.FormError("bad NSEC octets") + current += 2 + rdlen -= 2 + if rdlen < octets: + raise dns.exception.FormError("bad NSEC bitmap length") + bitmap = wire[current : current + octets] + current += octets + rdlen -= octets + windows.append((window, bitmap)) + if not origin is None: + next = next.relativize(origin) + return cls(rdclass, rdtype, next, windows) + + from_wire = classmethod(from_wire) + + def choose_relativity(self, origin = None, relativize = True): + self.next = self.next.choose_relativity(origin, relativize) + + def _cmp(self, other): + v = cmp(self.next, other.next) + if v == 0: + b1 = cStringIO.StringIO() + for (window, bitmap) in self.windows: + b1.write(chr(window)) + b1.write(chr(len(bitmap))) + b1.write(bitmap) + b2 = cStringIO.StringIO() + for (window, bitmap) in other.windows: + b2.write(chr(window)) + b2.write(chr(len(bitmap))) + b2.write(bitmap) + v = cmp(b1.getvalue(), b2.getvalue()) + return v |