209 lines
6.0 KiB
Python
209 lines
6.0 KiB
Python
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
|
|
|
|
# Copyright (C) 2003-2017 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 binascii
|
|
import re
|
|
from typing import List, Union
|
|
|
|
import dns.exception
|
|
import dns.ipv4
|
|
|
|
_leading_zero = re.compile(r"0+([0-9a-f]+)")
|
|
|
|
|
|
def inet_ntoa(address: bytes) -> str:
|
|
"""Convert an IPv6 address in binary form to text form.
|
|
|
|
*address*, a ``bytes``, the IPv6 address in binary form.
|
|
|
|
Raises ``ValueError`` if the address isn't 16 bytes long.
|
|
Returns a ``str``.
|
|
"""
|
|
|
|
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].decode()
|
|
# 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 m is not 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 range(8):
|
|
if chunks[i] != "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] == "ffff"):
|
|
# We have an embedded IPv4 address
|
|
if best_len == 6:
|
|
prefix = "::"
|
|
else:
|
|
prefix = "::ffff:"
|
|
thex = prefix + dns.ipv4.inet_ntoa(address[12:])
|
|
else:
|
|
thex = (
|
|
":".join(chunks[:best_start])
|
|
+ "::"
|
|
+ ":".join(chunks[best_start + best_len :])
|
|
)
|
|
else:
|
|
thex = ":".join(chunks)
|
|
return thex
|
|
|
|
|
|
_v4_ending = re.compile(rb"(.*):(\d+\.\d+\.\d+\.\d+)$")
|
|
_colon_colon_start = re.compile(rb"::.*")
|
|
_colon_colon_end = re.compile(rb".*::$")
|
|
|
|
|
|
def inet_aton(text: Union[str, bytes], ignore_scope: bool = False) -> bytes:
|
|
"""Convert an IPv6 address in text form to binary form.
|
|
|
|
*text*, a ``str``, the IPv6 address in textual form.
|
|
|
|
*ignore_scope*, a ``bool``. If ``True``, a scope will be ignored.
|
|
If ``False``, the default, it is an error for a scope to be present.
|
|
|
|
Returns a ``bytes``.
|
|
"""
|
|
|
|
#
|
|
# Our aim here is not something fast; we just want something that works.
|
|
#
|
|
if not isinstance(text, bytes):
|
|
btext = text.encode()
|
|
else:
|
|
btext = text
|
|
|
|
if ignore_scope:
|
|
parts = btext.split(b"%")
|
|
l = len(parts)
|
|
if l == 2:
|
|
btext = parts[0]
|
|
elif l > 2:
|
|
raise dns.exception.SyntaxError
|
|
|
|
if btext == b"":
|
|
raise dns.exception.SyntaxError
|
|
elif btext.endswith(b":") and not btext.endswith(b"::"):
|
|
raise dns.exception.SyntaxError
|
|
elif btext.startswith(b":") and not btext.startswith(b"::"):
|
|
raise dns.exception.SyntaxError
|
|
elif btext == b"::":
|
|
btext = b"0::"
|
|
#
|
|
# Get rid of the icky dot-quad syntax if we have it.
|
|
#
|
|
m = _v4_ending.match(btext)
|
|
if m is not None:
|
|
b = dns.ipv4.inet_aton(m.group(2))
|
|
btext = (
|
|
"{}:{:02x}{:02x}:{:02x}{:02x}".format(
|
|
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(btext)
|
|
if m is not None:
|
|
btext = btext[1:]
|
|
else:
|
|
m = _colon_colon_end.match(btext)
|
|
if m is not None:
|
|
btext = btext[:-1]
|
|
#
|
|
# Now canonicalize into 8 chunks of 4 hex digits each
|
|
#
|
|
chunks = btext.split(b":")
|
|
l = len(chunks)
|
|
if l > 8:
|
|
raise dns.exception.SyntaxError
|
|
seen_empty = False
|
|
canonical: List[bytes] = []
|
|
for c in chunks:
|
|
if c == b"":
|
|
if seen_empty:
|
|
raise dns.exception.SyntaxError
|
|
seen_empty = True
|
|
for _ in range(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
|
|
btext = b"".join(canonical)
|
|
|
|
#
|
|
# Finally we can go to binary.
|
|
#
|
|
try:
|
|
return binascii.unhexlify(btext)
|
|
except (binascii.Error, TypeError):
|
|
raise dns.exception.SyntaxError
|
|
|
|
|
|
_mapped_prefix = b"\x00" * 10 + b"\xff\xff"
|
|
|
|
|
|
def is_mapped(address: bytes) -> bool:
|
|
"""Is the specified address a mapped IPv4 address?
|
|
|
|
*address*, a ``bytes`` is an IPv6 address in binary form.
|
|
|
|
Returns a ``bool``.
|
|
"""
|
|
|
|
return address.startswith(_mapped_prefix)
|