247 lines
8.1 KiB
Python
247 lines
8.1 KiB
Python
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#-----------------------------------------------------------------------------
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# Copyright (c) 2008 by David P. D. Moss. All rights reserved.
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#
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# Released under the BSD license. See the LICENSE file for details.
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#-----------------------------------------------------------------------------
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"""Fallback routines for Python's standard library socket module"""
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from struct import unpack as _unpack, pack as _pack
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from netaddr.compat import _bytes_join, _is_str
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AF_INET = 2
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AF_INET6 = 10
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def inet_ntoa(packed_ip):
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"""
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Convert an IP address from 32-bit packed binary format to string format.
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"""
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if not _is_str(packed_ip):
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raise TypeError('string type expected, not %s' % type(packed_ip))
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if len(packed_ip) != 4:
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raise ValueError('invalid length of packed IP address string')
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return '%d.%d.%d.%d' % _unpack('4B', packed_ip)
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def _compact_ipv6_tokens(tokens):
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new_tokens = []
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positions = []
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start_index = None
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num_tokens = 0
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# Discover all runs of zeros.
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for idx, token in enumerate(tokens):
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if token == '0':
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if start_index is None:
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start_index = idx
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num_tokens += 1
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else:
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if num_tokens > 1:
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positions.append((num_tokens, start_index))
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start_index = None
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num_tokens = 0
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new_tokens.append(token)
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# Store any position not saved before loop exit.
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if num_tokens > 1:
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positions.append((num_tokens, start_index))
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# Replace first longest run with an empty string.
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if len(positions) != 0:
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# Locate longest, left-most run of zeros.
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positions.sort(key=lambda x: x[1])
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best_position = positions[0]
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for position in positions:
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if position[0] > best_position[0]:
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best_position = position
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# Replace chosen zero run.
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(length, start_idx) = best_position
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new_tokens = new_tokens[0:start_idx] + [''] + new_tokens[start_idx + length:]
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# Add start and end blanks so join creates '::'.
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if new_tokens[0] == '':
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new_tokens.insert(0, '')
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if new_tokens[-1] == '':
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new_tokens.append('')
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return new_tokens
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def inet_ntop(af, packed_ip):
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"""Convert an packed IP address of the given family to string format."""
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if af == AF_INET:
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# IPv4.
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return inet_ntoa(packed_ip)
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elif af == AF_INET6:
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# IPv6.
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if len(packed_ip) != 16 or not _is_str(packed_ip):
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raise ValueError('invalid length of packed IP address string')
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tokens = ['%x' % i for i in _unpack('>8H', packed_ip)]
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# Convert packed address to an integer value.
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words = list(_unpack('>8H', packed_ip))
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int_val = 0
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for i, num in enumerate(reversed(words)):
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word = num
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word = word << 16 * i
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int_val = int_val | word
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if 0xffff < int_val <= 0xffffffff or int_val >> 32 == 0xffff:
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# IPv4 compatible / mapped IPv6.
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packed_ipv4 = _pack('>2H', *[int(i, 16) for i in tokens[-2:]])
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ipv4_str = inet_ntoa(packed_ipv4)
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tokens = tokens[0:-2] + [ipv4_str]
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return ':'.join(_compact_ipv6_tokens(tokens))
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else:
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raise ValueError('unknown address family %d' % af)
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def _inet_pton_af_inet(ip_string):
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"""
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Convert an IP address in string format (123.45.67.89) to the 32-bit packed
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binary format used in low-level network functions. Differs from inet_aton
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by only support decimal octets. Using octal or hexadecimal values will
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raise a ValueError exception.
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"""
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#TODO: optimise this ... use inet_aton with mods if available ...
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if _is_str(ip_string):
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invalid_addr = ValueError('illegal IP address string %r' % ip_string)
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# Support for hexadecimal and octal octets.
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tokens = ip_string.split('.')
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# Pack octets.
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if len(tokens) == 4:
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words = []
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for token in tokens:
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if token.startswith('0x') or (token.startswith('0') and len(token) > 1):
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raise invalid_addr
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try:
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octet = int(token)
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except ValueError:
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raise invalid_addr
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if (octet >> 8) != 0:
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raise invalid_addr
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words.append(_pack('B', octet))
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return _bytes_join(words)
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else:
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raise invalid_addr
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raise ValueError('argument should be a string, not %s' % type(ip_string))
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def inet_pton(af, ip_string):
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"""
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Convert an IP address from string format to a packed string suitable for
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use with low-level network functions.
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"""
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if af == AF_INET:
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# IPv4.
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return _inet_pton_af_inet(ip_string)
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elif af == AF_INET6:
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invalid_addr = ValueError('illegal IP address string %r' % ip_string)
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# IPv6.
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values = []
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if not _is_str(ip_string):
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raise invalid_addr
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if 'x' in ip_string:
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# Don't accept hextets with the 0x prefix.
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raise invalid_addr
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if '::' in ip_string:
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if ip_string == '::':
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# Unspecified address.
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return '\x00'.encode() * 16
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# IPv6 compact mode.
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try:
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prefix, suffix = ip_string.split('::')
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except ValueError:
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raise invalid_addr
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l_prefix = []
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l_suffix = []
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if prefix != '':
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l_prefix = prefix.split(':')
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if suffix != '':
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l_suffix = suffix.split(':')
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# IPv6 compact IPv4 compatibility mode.
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if len(l_suffix) and '.' in l_suffix[-1]:
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ipv4_str = _inet_pton_af_inet(l_suffix.pop())
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l_suffix.append('%x' % _unpack('>H', ipv4_str[0:2])[0])
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l_suffix.append('%x' % _unpack('>H', ipv4_str[2:4])[0])
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token_count = len(l_prefix) + len(l_suffix)
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if not 0 <= token_count <= 8 - 1:
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raise invalid_addr
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gap_size = 8 - ( len(l_prefix) + len(l_suffix) )
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values = (
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[_pack('>H', int(i, 16)) for i in l_prefix] +
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['\x00\x00'.encode() for i in range(gap_size)] +
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[_pack('>H', int(i, 16)) for i in l_suffix]
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)
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try:
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for token in l_prefix + l_suffix:
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word = int(token, 16)
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if not 0 <= word <= 0xffff:
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raise invalid_addr
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except ValueError:
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raise invalid_addr
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else:
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# IPv6 verbose mode.
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if ':' in ip_string:
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tokens = ip_string.split(':')
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if '.' in ip_string:
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ipv6_prefix = tokens[:-1]
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if ipv6_prefix[:-1] != ['0', '0', '0', '0', '0']:
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raise invalid_addr
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if ipv6_prefix[-1].lower() not in ('0', 'ffff'):
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raise invalid_addr
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# IPv6 verbose IPv4 compatibility mode.
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if len(tokens) != 7:
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raise invalid_addr
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ipv4_str = _inet_pton_af_inet(tokens.pop())
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tokens.append('%x' % _unpack('>H', ipv4_str[0:2])[0])
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tokens.append('%x' % _unpack('>H', ipv4_str[2:4])[0])
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values = [_pack('>H', int(i, 16)) for i in tokens]
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else:
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# IPv6 verbose mode.
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if len(tokens) != 8:
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raise invalid_addr
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try:
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tokens = [int(token, 16) for token in tokens]
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for token in tokens:
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if not 0 <= token <= 0xffff:
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raise invalid_addr
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except ValueError:
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raise invalid_addr
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values = [_pack('>H', i) for i in tokens]
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else:
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raise invalid_addr
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return _bytes_join(values)
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else:
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raise ValueError('Unknown address family %d' % af)
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