diff options
Diffstat (limited to 'third_party/dnspython/dns/ipv6.py')
-rw-r--r-- | third_party/dnspython/dns/ipv6.py | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/third_party/dnspython/dns/ipv6.py b/third_party/dnspython/dns/ipv6.py new file mode 100644 index 00000000000..69db34a7dea --- /dev/null +++ b/third_party/dnspython/dns/ipv6.py @@ -0,0 +1,163 @@ +# 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 dns.exception +import dns.ipv4 + +_leading_zero = re.compile(r'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 = address.encode('hex_codec') + 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] != '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 > 0: + 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:' + hex = prefix + dns.ipv4.inet_ntoa(address[12:]) + else: + hex = ':'.join(chunks[:best_start]) + '::' + \ + ':'.join(chunks[best_start + best_len:]) + else: + hex = ':'.join(chunks) + return hex + +_v4_ending = re.compile(r'(.*):(\d+\.\d+\.\d+\.\d+)$') +_colon_colon_start = re.compile(r'::.*') +_colon_colon_end = re.compile(r'.*::$') + +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 text == '::': + text = '0::' + # + # Get rid of the icky dot-quad syntax if we have it. + # + m = _v4_ending.match(text) + if not m is None: + b = dns.ipv4.inet_aton(m.group(2)) + text = "%s:%02x%02x:%02x%02x" % (m.group(1), ord(b[0]), ord(b[1]), + ord(b[2]), ord(b[3])) + # + # 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(':') + l = len(chunks) + if l > 8: + raise dns.exception.SyntaxError + seen_empty = False + canonical = [] + for c in chunks: + if c == '': + if seen_empty: + raise dns.exception.SyntaxError + seen_empty = True + for i in xrange(0, 8 - l + 1): + canonical.append('0000') + else: + lc = len(c) + if lc > 4: + raise dns.exception.SyntaxError + if lc != 4: + c = ('0' * (4 - lc)) + c + canonical.append(c) + if l < 8 and not seen_empty: + raise dns.exception.SyntaxError + text = ''.join(canonical) + + # + # Finally we can go to binary. + # + try: + return text.decode('hex_codec') + except TypeError: + raise dns.exception.SyntaxError |