/usr/lib/python3/dist-packages/dns/ipv6.py is in python3-dnspython 1.15.0-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 | # 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.
"""IPv6 helper functions."""
import re
import binascii
import dns.exception
import dns.ipv4
from ._compat import xrange, binary_type, maybe_decode
_leading_zero = re.compile(b'0+([0-9a-f]+)')
def inet_ntoa(address):
"""Convert a network format IPv6 address into text.
@param address: the binary address
@type address: string
@rtype: string
@raises ValueError: the address isn't 16 bytes long
"""
if len(address) != 16:
raise ValueError("IPv6 addresses are 16 bytes long")
hex = binascii.hexlify(address)
chunks = []
i = 0
l = len(hex)
while i < l:
chunk = hex[i : i + 4]
# strip leading zeros. we do this with an re instead of
# with lstrip() because lstrip() didn't support chars until
# python 2.2.2
m = _leading_zero.match(chunk)
if not m is None:
chunk = m.group(1)
chunks.append(chunk)
i += 4
#
# Compress the longest subsequence of 0-value chunks to ::
#
best_start = 0
best_len = 0
start = -1
last_was_zero = False
for i in xrange(8):
if chunks[i] != b'0':
if last_was_zero:
end = i
current_len = end - start
if current_len > best_len:
best_start = start
best_len = current_len
last_was_zero = False
elif not last_was_zero:
start = i
last_was_zero = True
if last_was_zero:
end = 8
current_len = end - start
if current_len > best_len:
best_start = start
best_len = current_len
if best_len > 1:
if best_start == 0 and \
(best_len == 6 or
best_len == 5 and chunks[5] == b'ffff'):
# We have an embedded IPv4 address
if best_len == 6:
prefix = b'::'
else:
prefix = b'::ffff:'
hex = prefix + dns.ipv4.inet_ntoa(address[12:])
else:
hex = b':'.join(chunks[:best_start]) + b'::' + \
b':'.join(chunks[best_start + best_len:])
else:
hex = b':'.join(chunks)
return maybe_decode(hex)
_v4_ending = re.compile(b'(.*):(\d+\.\d+\.\d+\.\d+)$')
_colon_colon_start = re.compile(b'::.*')
_colon_colon_end = re.compile(b'.*::$')
def inet_aton(text):
"""Convert a text format IPv6 address into network format.
@param text: the textual address
@type text: string
@rtype: string
@raises dns.exception.SyntaxError: the text was not properly formatted
"""
#
# Our aim here is not something fast; we just want something that works.
#
if not isinstance(text, binary_type):
text = text.encode()
if text == b'::':
text = b'0::'
#
# Get rid of the icky dot-quad syntax if we have it.
#
m = _v4_ending.match(text)
if not m is None:
b = bytearray(dns.ipv4.inet_aton(m.group(2)))
text = (u"%s:%02x%02x:%02x%02x" % (m.group(1).decode(), b[0], b[1],
b[2], b[3])).encode()
#
# Try to turn '::<whatever>' into ':<whatever>'; if no match try to
# turn '<whatever>::' into '<whatever>:'
#
m = _colon_colon_start.match(text)
if not m is None:
text = text[1:]
else:
m = _colon_colon_end.match(text)
if not m is None:
text = text[:-1]
#
# Now canonicalize into 8 chunks of 4 hex digits each
#
chunks = text.split(b':')
l = len(chunks)
if l > 8:
raise dns.exception.SyntaxError
seen_empty = False
canonical = []
for c in chunks:
if c == b'':
if seen_empty:
raise dns.exception.SyntaxError
seen_empty = True
for i in xrange(0, 8 - l + 1):
canonical.append(b'0000')
else:
lc = len(c)
if lc > 4:
raise dns.exception.SyntaxError
if lc != 4:
c = (b'0' * (4 - lc)) + c
canonical.append(c)
if l < 8 and not seen_empty:
raise dns.exception.SyntaxError
text = b''.join(canonical)
#
# Finally we can go to binary.
#
try:
return binascii.unhexlify(text)
except (binascii.Error, TypeError):
raise dns.exception.SyntaxError
_mapped_prefix = b'\x00' * 10 + b'\xff\xff'
def is_mapped(address):
return address.startswith(_mapped_prefix)
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