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# Copyright (C) 2003-2007, 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.
import cStringIO
import struct
import dns.exception
import dns.inet
import dns.rdata
import dns.tokenizer
class APLItem(object):
"""An APL list item.
@ivar family: the address family (IANA address family registry)
@type family: int
@ivar negation: is this item negated?
@type negation: bool
@ivar address: the address
@type address: string
@ivar prefix: the prefix length
@type prefix: int
"""
__slots__ = ['family', 'negation', 'address', 'prefix']
def __init__(self, family, negation, address, prefix):
self.family = family
self.negation = negation
self.address = address
self.prefix = prefix
def __str__(self):
if self.negation:
return "!%d:%s/%s" % (self.family, self.address, self.prefix)
else:
return "%d:%s/%s" % (self.family, self.address, self.prefix)
def to_wire(self, file):
if self.family == 1:
address = dns.inet.inet_pton(dns.inet.AF_INET, self.address)
elif self.family == 2:
address = dns.inet.inet_pton(dns.inet.AF_INET6, self.address)
else:
address = self.address.decode('hex_codec')
#
# Truncate least significant zero bytes.
#
last = 0
for i in xrange(len(address) - 1, -1, -1):
if address[i] != chr(0):
last = i + 1
break
address = address[0 : last]
l = len(address)
assert l < 128
if self.negation:
l |= 0x80
header = struct.pack('!HBB', self.family, self.prefix, l)
file.write(header)
file.write(address)
class APL(dns.rdata.Rdata):
"""APL record.
@ivar items: a list of APL items
@type items: list of APL_Item
@see: RFC 3123"""
__slots__ = ['items']
def __init__(self, rdclass, rdtype, items):
super(APL, self).__init__(rdclass, rdtype)
self.items = items
def to_text(self, origin=None, relativize=True, **kw):
return ' '.join(map(lambda x: str(x), self.items))
def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
items = []
while 1:
token = tok.get().unescape()
if token.is_eol_or_eof():
break
item = token.value
if item[0] == '!':
negation = True
item = item[1:]
else:
negation = False
(family, rest) = item.split(':', 1)
family = int(family)
(address, prefix) = rest.split('/', 1)
prefix = int(prefix)
item = APLItem(family, negation, address, prefix)
items.append(item)
return cls(rdclass, rdtype, items)
from_text = classmethod(from_text)
def to_wire(self, file, compress = None, origin = None):
for item in self.items:
item.to_wire(file)
def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
items = []
while 1:
if rdlen < 4:
raise dns.exception.FormError
header = struct.unpack('!HBB', wire[current : current + 4])
afdlen = header[2]
if afdlen > 127:
negation = True
afdlen -= 128
else:
negation = False
current += 4
rdlen -= 4
if rdlen < afdlen:
raise dns.exception.FormError
address = wire[current : current + afdlen].unwrap()
l = len(address)
if header[0] == 1:
if l < 4:
address += '\x00' * (4 - l)
address = dns.inet.inet_ntop(dns.inet.AF_INET, address)
elif header[0] == 2:
if l < 16:
address += '\x00' * (16 - l)
address = dns.inet.inet_ntop(dns.inet.AF_INET6, address)
else:
#
# This isn't really right according to the RFC, but it
# seems better than throwing an exception
#
address = address.encode('hex_codec')
current += afdlen
rdlen -= afdlen
item = APLItem(header[0], negation, address, header[1])
items.append(item)
if rdlen == 0:
break
return cls(rdclass, rdtype, items)
from_wire = classmethod(from_wire)
def _cmp(self, other):
f = cStringIO.StringIO()
self.to_wire(f)
wire1 = f.getvalue()
f.seek(0)
f.truncate()
other.to_wire(f)
wire2 = f.getvalue()
f.close()
return cmp(wire1, wire2)
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