+
−# -*- coding: UTF-8 -*-
+
−# Copyright (c) 2011, Pascal Volk
+
−# See COPYING for distribution information.
+
−"""
+
−    VirtualMailManager.network
+
−    ~~~~~~~~~~~~~~~~~~~~~~~~~~
+
−
+
−    Network/IP address related class and function
+
−"""
+
−
+
−import socket
+
−
+
−
+
−class NetInfo(object):
+
−    """Simple class for CIDR network addresses an IP addresses."""
+
−    __slots__ = ('_addr', '_prefix', '_bits_max', '_family', '_nw_addr')
+
−
+
−    def __init__(self, nw_address):
+
−        """Creates a new `NetInfo` instance.
+
−
+
−        Argument:
+
−
+
−        `nw_address` : basestring
+
−          string representation of an IPv4/IPv6 address or network address.
+
−          E.g. 192.0.2.13, 192.0.2.0/24, 2001:db8::/32 or ::1
+
−          When the address has no netmask the prefix length will be set to
+
−          32 for IPv4 addresses and 128 for IPv6 addresses.
+
−        """
+
−        self._addr = None
+
−        self._prefix = 0
+
−        self._bits_max = 0
+
−        self._family = 0
+
−        self._nw_addr = nw_address
+
−        self._parse_net_range()
+
−
+
−    def __hash__(self):
+
−        return hash((self._addr, self._family, self._prefix))
+
−
+
−    def __repr__(self):
+
−        return "NetInfo('%s')" % self._nw_addr
+
−
+
−    def _parse_net_range(self):
+
−        """Parse the network range of `self._nw_addr and assign values
+
−        to the class attributes.
+
−        `"""
+
−        sep = '/'
+
−        if self._nw_addr.count(sep):
+
−            ip_address, sep, self._prefix = self._nw_addr.partition(sep)
+
−            self._family, self._addr = get_ip_addr_info(ip_address)
+
−        else:
+
−            self._family, self._addr = get_ip_addr_info(self._nw_addr)
+
−        self._bits_max = (128, 32)[self._family is socket.AF_INET]
+
−        if self._prefix is 0:
+
−            self._prefix = self._bits_max
+
−        else:
+
−            try:
+
−                self._prefix = int(self._prefix)
+
−            except ValueError:
+
−                raise ValueError('Invalid prefix length: %r' % self._prefix)
+
−        if self._prefix > self._bits_max or self._prefix < 0:
+
−            raise ValueError('Invalid prefix length: %r' % self._prefix)
+
−
+
−    @property
+
−    def family(self):
+
−        """Address family: `socket.AF_INET` or `socket.AF_INET6`"""
+
−        return self._family
+
−
+
−    def address_in_net(self, ip_address):
+
−        """Checks if the `ip_address` belongs to the same subnet."""
+
−        family, address = get_ip_addr_info(ip_address)
+
−        if family != self._family:
+
−            return False
+
−        return address >> self._bits_max - self._prefix == \
+
−               self._addr >> self._bits_max - self._prefix
+
−
+
−
+
−def get_ip_addr_info(ip_address):
+
−    """Checks if the string `ip_address` is a valid IPv4 or IPv6 address.
+
−
+
−    When the `ip_address` could be validated successfully a tuple
+
−    `(address_family, address_as_long)` will be returned. The
+
−    `address_family`will be either `socket.AF_INET` or `socket.AF_INET6`.
+
−    """
+
−    if not isinstance(ip_address, basestring) or not ip_address:
+
−        raise TypeError('ip_address must be a non empty string.')
+
−    if not ip_address.count(':'):
+
−        family = socket.AF_INET
+
−        try:
+
−            address = socket.inet_aton(ip_address)
+
−        except socket.error:
+
−            raise ValueError('Not a valid IPv4 address: %r' % ip_address)
+
−    elif not socket.has_ipv6:
+
−        raise ValueError('Unsupported IP address (IPv6): %r' % ip_address)
+
−    else:
+
−        family = socket.AF_INET6
+
−        try:
+
−            address = socket.inet_pton(family, ip_address)
+
−        except socket.error:
+
−            raise ValueError('Not a valid IPv6 address: %r' % ip_address)
+
−    return (family, long(address.encode('hex'), 16))