geo-rep: implement IP address based access control

- gsyncd gets allow-network tunable which is expected to
  hold a comma-separated list of IP network addresses
- for IP addess matching, bring in ipaddr module from Google
  (http://code.google.com/p/ipaddr-py/, rev. trunk@225)

This will let users control master's access to slave's volumes
until we implement unprivileged geo-rep (delayed due to some
technical issues). It's also needed for the completeness of
our hardening efforts, as plain file slaves won't be able
to work with an unprivileged gsyncd.

Change-Id: I58431cba6592f8672e93ea89a5eef478905b00b9
BUG: 2825
Reviewed-on: http://review.gluster.com/488
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 1907 insertions, 0 deletions

diff --git a/contrib/ipaddr-py/ipaddr.py b/contrib/ipaddr-py/ipaddr.py
new file mode 100644
index 000000000..a89298a31
--- /dev/null
+++ b/contrib/ipaddr-py/ipaddr.py
@@ -0,0 +1,1907 @@
+#!/usr/bin/python
+#
+# Copyright 2007 Google Inc.
+#  Licensed to PSF under a Contributor Agreement.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied. See the License for the specific language governing
+# permissions and limitations under the License.
+
+"""A fast, lightweight IPv4/IPv6 manipulation library in Python.
+
+This library is used to create/poke/manipulate IPv4 and IPv6 addresses
+and networks.
+
+"""
+
+__version__ = 'trunk'
+
+import struct
+
+IPV4LENGTH = 32
+IPV6LENGTH = 128
+
+
+class AddressValueError(ValueError):
+    """A Value Error related to the address."""
+
+
+class NetmaskValueError(ValueError):
+    """A Value Error related to the netmask."""
+
+
+def IPAddress(address, version=None):
+    """Take an IP string/int and return an object of the correct type.
+
+    Args:
+        address: A string or integer, the IP address.  Either IPv4 or
+          IPv6 addresses may be supplied; integers less than 2**32 will
+          be considered to be IPv4 by default.
+        version: An Integer, 4 or 6. If set, don't try to automatically
+          determine what the IP address type is. important for things
+          like IPAddress(1), which could be IPv4, '0.0.0.1',  or IPv6,
+          '::1'.
+
+    Returns:
+        An IPv4Address or IPv6Address object.
+
+    Raises:
+        ValueError: if the string passed isn't either a v4 or a v6
+          address.
+
+    """
+    if version:
+        if version == 4:
+            return IPv4Address(address)
+        elif version == 6:
+            return IPv6Address(address)
+
+    try:
+        return IPv4Address(address)
+    except (AddressValueError, NetmaskValueError):
+        pass
+
+    try:
+        return IPv6Address(address)
+    except (AddressValueError, NetmaskValueError):
+        pass
+
+    raise ValueError('%r does not appear to be an IPv4 or IPv6 address' %
+                     address)
+
+
+def IPNetwork(address, version=None, strict=False):
+    """Take an IP string/int and return an object of the correct type.
+
+    Args:
+        address: A string or integer, the IP address.  Either IPv4 or
+          IPv6 addresses may be supplied; integers less than 2**32 will
+          be considered to be IPv4 by default.
+        version: An Integer, if set, don't try to automatically
+          determine what the IP address type is. important for things
+          like IPNetwork(1), which could be IPv4, '0.0.0.1/32', or IPv6,
+          '::1/128'.
+
+    Returns:
+        An IPv4Network or IPv6Network object.
+
+    Raises:
+        ValueError: if the string passed isn't either a v4 or a v6
+          address. Or if a strict network was requested and a strict
+          network wasn't given.
+
+    """
+    if version:
+        if version == 4:
+            return IPv4Network(address, strict)
+        elif version == 6:
+            return IPv6Network(address, strict)
+
+    try:
+        return IPv4Network(address, strict)
+    except (AddressValueError, NetmaskValueError):
+        pass
+
+    try:
+        return IPv6Network(address, strict)
+    except (AddressValueError, NetmaskValueError):
+        pass
+
+    raise ValueError('%r does not appear to be an IPv4 or IPv6 network' %
+                     address)
+
+
+def v4_int_to_packed(address):
+    """The binary representation of this address.
+
+    Args:
+        address: An integer representation of an IPv4 IP address.
+
+    Returns:
+        The binary representation of this address.
+
+    Raises:
+        ValueError: If the integer is too large to be an IPv4 IP
+          address.
+    """
+    if address > _BaseV4._ALL_ONES:
+        raise ValueError('Address too large for IPv4')
+    return struct.pack('!I', address)
+
+
+def v6_int_to_packed(address):
+    """The binary representation of this address.
+
+    Args:
+        address: An integer representation of an IPv4 IP address.
+
+    Returns:
+        The binary representation of this address.
+    """
+    return struct.pack('!QQ', address >> 64, address & (2**64 - 1))
+
+
+def _find_address_range(addresses):
+    """Find a sequence of addresses.
+
+    Args:
+        addresses: a list of IPv4 or IPv6 addresses.
+
+    Returns:
+        A tuple containing the first and last IP addresses in the sequence.
+
+    """
+    first = last = addresses[0]
+    for ip in addresses[1:]:
+        if ip._ip == last._ip + 1:
+            last = ip
+        else:
+            break
+    return (first, last)
+
+def _get_prefix_length(number1, number2, bits):
+    """Get the number of leading bits that are same for two numbers.
+
+    Args:
+        number1: an integer.
+        number2: another integer.
+        bits: the maximum number of bits to compare.
+
+    Returns:
+        The number of leading bits that are the same for two numbers.
+
+    """
+    for i in range(bits):
+        if number1 >> i == number2 >> i:
+            return bits - i
+    return 0
+
+def _count_righthand_zero_bits(number, bits):
+    """Count the number of zero bits on the right hand side.
+
+    Args:
+        number: an integer.
+        bits: maximum number of bits to count.
+
+    Returns:
+        The number of zero bits on the right hand side of the number.
+
+    """
+    if number == 0:
+        return bits
+    for i in range(bits):
+        if (number >> i) % 2:
+            return i
+
+def summarize_address_range(first, last):
+    """Summarize a network range given the first and last IP addresses.
+
+    Example:
+        >>> summarize_address_range(IPv4Address('1.1.1.0'),
+            IPv4Address('1.1.1.130'))
+        [IPv4Network('1.1.1.0/25'), IPv4Network('1.1.1.128/31'),
+        IPv4Network('1.1.1.130/32')]
+
+    Args:
+        first: the first IPv4Address or IPv6Address in the range.
+        last: the last IPv4Address or IPv6Address in the range.
+
+    Returns:
+        The address range collapsed to a list of IPv4Network's or
+        IPv6Network's.
+
+    Raise:
+        TypeError:
+            If the first and last objects are not IP addresses.
+            If the first and last objects are not the same version.
+        ValueError:
+            If the last object is not greater than the first.
+            If the version is not 4 or 6.
+
+    """
+    if not (isinstance(first, _BaseIP) and isinstance(last, _BaseIP)):
+        raise TypeError('first and last must be IP addresses, not networks')
+    if first.version != last.version:
+        raise TypeError("%s and %s are not of the same version" % (
+                str(first), str(last)))
+    if first > last:
+        raise ValueError('last IP address must be greater than first')
+
+    networks = []
+
+    if first.version == 4:
+        ip = IPv4Network
+    elif first.version == 6:
+        ip = IPv6Network
+    else:
+        raise ValueError('unknown IP version')
+
+    ip_bits = first._max_prefixlen
+    first_int = first._ip
+    last_int = last._ip
+    while first_int <= last_int:
+        nbits = _count_righthand_zero_bits(first_int, ip_bits)
+        current = None
+        while nbits >= 0:
+            addend = 2**nbits - 1
+            current = first_int + addend
+            nbits -= 1
+            if current <= last_int:
+                break
+        prefix = _get_prefix_length(first_int, current, ip_bits)
+        net = ip('%s/%d' % (str(first), prefix))
+        networks.append(net)
+        if current == ip._ALL_ONES:
+            break
+        first_int = current + 1
+        first = IPAddress(first_int, version=first._version)
+    return networks
+
+def _collapse_address_list_recursive(addresses):
+    """Loops through the addresses, collapsing concurrent netblocks.
+
+    Example:
+
+        ip1 = IPv4Network('1.1.0.0/24')
+        ip2 = IPv4Network('1.1.1.0/24')
+        ip3 = IPv4Network('1.1.2.0/24')
+        ip4 = IPv4Network('1.1.3.0/24')
+        ip5 = IPv4Network('1.1.4.0/24')
+        ip6 = IPv4Network('1.1.0.1/22')
+
+        _collapse_address_list_recursive([ip1, ip2, ip3, ip4, ip5, ip6]) ->
+          [IPv4Network('1.1.0.0/22'), IPv4Network('1.1.4.0/24')]
+
+        This shouldn't be called directly; it is called via
+          collapse_address_list([]).
+
+    Args:
+        addresses: A list of IPv4Network's or IPv6Network's
+
+    Returns:
+        A list of IPv4Network's or IPv6Network's depending on what we were
+        passed.
+
+    """
+    ret_array = []
+    optimized = False
+
+    for cur_addr in addresses:
+        if not ret_array:
+            ret_array.append(cur_addr)
+            continue
+        if cur_addr in ret_array[-1]:
+            optimized = True
+        elif cur_addr == ret_array[-1].supernet().subnet()[1]:
+            ret_array.append(ret_array.pop().supernet())
+            optimized = True
+        else:
+            ret_array.append(cur_addr)
+
+    if optimized:
+        return _collapse_address_list_recursive(ret_array)
+
+    return ret_array
+
+
+def collapse_address_list(addresses):
+    """Collapse a list of IP objects.
+
+    Example:
+        collapse_address_list([IPv4('1.1.0.0/24'), IPv4('1.1.1.0/24')]) ->
+          [IPv4('1.1.0.0/23')]
+
+    Args:
+        addresses: A list of IPv4Network or IPv6Network objects.
+
+    Returns:
+        A list of IPv4Network or IPv6Network objects depending on what we
+        were passed.
+
+    Raises:
+        TypeError: If passed a list of mixed version objects.
+
+    """
+    i = 0
+    addrs = []
+    ips = []
+    nets = []
+
+    # split IP addresses and networks
+    for ip in addresses:
+        if isinstance(ip, _BaseIP):
+            if ips and ips[-1]._version != ip._version:
+                raise TypeError("%s and %s are not of the same version" % (
+                        str(ip), str(ips[-1])))
+            ips.append(ip)
+        elif ip._prefixlen == ip._max_prefixlen:
+            if ips and ips[-1]._version != ip._version:
+                raise TypeError("%s and %s are not of the same version" % (
+                        str(ip), str(ips[-1])))
+            ips.append(ip.ip)
+        else:
+            if nets and nets[-1]._version != ip._version:
+                raise TypeError("%s and %s are not of the same version" % (
+                        str(ip), str(ips[-1])))
+            nets.append(ip)
+
+    # sort and dedup
+    ips = sorted(set(ips))
+    nets = sorted(set(nets))
+
+    while i < len(ips):
+        (first, last) = _find_address_range(ips[i:])
+        i = ips.index(last) + 1
+        addrs.extend(summarize_address_range(first, last))
+
+    return _collapse_address_list_recursive(sorted(
+        addrs + nets, key=_BaseNet._get_networks_key))
+
+# backwards compatibility
+CollapseAddrList = collapse_address_list
+
+# Test whether this Python implementation supports byte objects that
+# are not identical to str ones.
+# We need to exclude platforms where bytes == str so that we can
+# distinguish between packed representations and strings, for example
+# b'12::' (the IPv4 address 49.50.58.58) and '12::' (an IPv6 address).
+try:
+    _compat_has_real_bytes = bytes is not str
+except NameError: # <Python2.6
+    _compat_has_real_bytes = False
+
+def get_mixed_type_key(obj):
+    """Return a key suitable for sorting between networks and addresses.
+
+    Address and Network objects are not sortable by default; they're
+    fundamentally different so the expression
+
+        IPv4Address('1.1.1.1') <= IPv4Network('1.1.1.1/24')
+
+    doesn't make any sense.  There are some times however, where you may wish
+    to have ipaddr sort these for you anyway. If you need to do this, you
+    can use this function as the key= argument to sorted().
+
+    Args:
+      obj: either a Network or Address object.
+    Returns:
+      appropriate key.
+
+    """
+    if isinstance(obj, _BaseNet):
+        return obj._get_networks_key()
+    elif isinstance(obj, _BaseIP):
+        return obj._get_address_key()
+    return NotImplemented
+
+class _IPAddrBase(object):
+
+    """The mother class."""
+
+    def __index__(self):
+        return self._ip
+
+    def __int__(self):
+        return self._ip
+
+    def __hex__(self):
+        return hex(self._ip)
+
+    @property
+    def exploded(self):
+        """Return the longhand version of the IP address as a string."""
+        return self._explode_shorthand_ip_string()
+
+    @property
+    def compressed(self):
+        """Return the shorthand version of the IP address as a string."""
+        return str(self)
+
+
+class _BaseIP(_IPAddrBase):
+
+    """A generic IP object.
+
+    This IP class contains the version independent methods which are
+    used by single IP addresses.
+
+    """
+
+    def __init__(self, address):
+        if (not (_compat_has_real_bytes and isinstance(address, bytes))
+            and '/' in str(address)):
+            raise AddressValueError(address)
+
+    def __eq__(self, other):
+        try:
+            return (self._ip == other._ip
+                    and self._version == other._version)
+        except AttributeError:
+            return NotImplemented
+
+    def __ne__(self, other):
+        eq = self.__eq__(other)
+        if eq is NotImplemented:
+            return NotImplemented
+        return not eq
+
+    def __le__(self, other):
+        gt = self.__gt__(other)
+        if gt is NotImplemented:
+            return NotImplemented
+        return not gt
+
+    def __ge__(self, other):
+        lt = self.__lt__(other)
+        if lt is NotImplemented:
+            return NotImplemented
+        return not lt
+
+    def __lt__(self, other):
+        if self._version != other._version:
+            raise TypeError('%s and %s are not of the same version' % (
+                    str(self), str(other)))
+        if not isinstance(other, _BaseIP):
+            raise TypeError('%s and %s are not of the same type' % (
+                    str(self), str(other)))
+        if self._ip != other._ip:
+            return self._ip < other._ip
+        return False
+
+    def __gt__(self, other):
+        if self._version != other._version:
+            raise TypeError('%s and %s are not of the same version' % (
+                    str(self), str(other)))
+        if not isinstance(other, _BaseIP):
+            raise TypeError('%s and %s are not of the same type' % (
+                    str(self), str(other)))
+        if self._ip != other._ip:
+            return self._ip > other._ip
+        return False
+
+    # Shorthand for Integer addition and subtraction. This is not
+    # meant to ever support addition/subtraction of addresses.
+    def __add__(self, other):
+        if not isinstance(other, int):
+            return NotImplemented
+        return IPAddress(int(self) + other, version=self._version)
+
+    def __sub__(self, other):
+        if not isinstance(other, int):
+            return NotImplemented
+        return IPAddress(int(self) - other, version=self._version)
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, str(self))
+
+    def __str__(self):
+        return  '%s' % self._string_from_ip_int(self._ip)
+
+    def __hash__(self):
+        return hash(hex(long(self._ip)))
+
+    def _get_address_key(self):
+        return (self._version, self)
+
+    @property
+    def version(self):
+        raise NotImplementedError('BaseIP has no version')
+
+
+class _BaseNet(_IPAddrBase):
+
+    """A generic IP object.
+
+    This IP class contains the version independent methods which are
+    used by networks.
+
+    """
+
+    def __init__(self, address):
+        self._cache = {}
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, str(self))
+
+    def iterhosts(self):
+        """Generate Iterator over usable hosts in a network.
+
+           This is like __iter__ except it doesn't return the network
+           or broadcast addresses.
+
+        """
+        cur = int(self.network) + 1
+        bcast = int(self.broadcast) - 1
+        while cur <= bcast:
+            cur += 1
+            yield IPAddress(cur - 1, version=self._version)
+
+    def __iter__(self):
+        cur = int(self.network)
+        bcast = int(self.broadcast)
+        while cur <= bcast:
+            cur += 1
+            yield IPAddress(cur - 1, version=self._version)
+
+    def __getitem__(self, n):
+        network = int(self.network)
+        broadcast = int(self.broadcast)
+        if n >= 0:
+            if network + n > broadcast:
+                raise IndexError
+            return IPAddress(network + n, version=self._version)
+        else:
+            n += 1
+            if broadcast + n < network:
+                raise IndexError
+            return IPAddress(broadcast + n, version=self._version)
+
+    def __lt__(self, other):
+        if self._version != other._version:
+            raise TypeError('%s and %s are not of the same version' % (
+                    str(self), str(other)))
+        if not isinstance(other, _BaseNet):
+            raise TypeError('%s and %s are not of the same type' % (
+                    str(self), str(other)))
+        if self.network != other.network:
+            return self.network < other.network
+        if self.netmask != other.netmask:
+            return self.netmask < other.netmask
+        return False
+
+    def __gt__(self, other):
+        if self._version != other._version:
+            raise TypeError('%s and %s are not of the same version' % (
+                    str(self), str(other)))
+        if not isinstance(other, _BaseNet):
+            raise TypeError('%s and %s are not of the same type' % (
+                    str(self), str(other)))
+        if self.network != other.network:
+            return self.network > other.network
+        if self.netmask != other.netmask:
+            return self.netmask > other.netmask
+        return False
+
+    def __le__(self, other):
+        gt = self.__gt__(other)
+        if gt is NotImplemented:
+            return NotImplemented
+        return not gt
+
+    def __ge__(self, other):
+        lt = self.__lt__(other)
+        if lt is NotImplemented:
+            return NotImplemented
+        return not lt
+
+    def __eq__(self, other):
+        try:
+            return (self._version == other._version
+                    and self.network == other.network
+                    and int(self.netmask) == int(other.netmask))
+        except AttributeError:
+            if isinstance(other, _BaseIP):
+                return (self._version == other._version
+                        and self._ip == other._ip)
+
+    def __ne__(self, other):
+        eq = self.__eq__(other)
+        if eq is NotImplemented:
+            return NotImplemented
+        return not eq
+
+    def __str__(self):
+        return  '%s/%s' % (str(self.ip),
+                           str(self._prefixlen))
+
+    def __hash__(self):
+        return hash(int(self.network) ^ int(self.netmask))
+
+    def __contains__(self, other):
+        # always false if one is v4 and the other is v6.
+        if self._version != other._version:
+          return False
+        # dealing with another network.
+        if isinstance(other, _BaseNet):
+            return (self.network <= other.network and
+                    self.broadcast >= other.broadcast)
+        # dealing with another address
+        else:
+            return (int(self.network) <= int(other._ip) <=
+                    int(self.broadcast))
+
+    def overlaps(self, other):
+        """Tell if self is partly contained in other."""
+        return self.network in other or self.broadcast in other or (
+            other.network in self or other.broadcast in self)
+
+    @property
+    def network(self):
+        x = self._cache.get('network')
+        if x is None:
+            x = IPAddress(self._ip & int(self.netmask), version=self._version)
+            self._cache['network'] = x
+        return x
+
+    @property
+    def broadcast(self):
+        x = self._cache.get('broadcast')
+        if x is None:
+            x = IPAddress(self._ip | int(self.hostmask), version=self._version)
+            self._cache['broadcast'] = x
+        return x
+
+    @property
+    def hostmask(self):
+        x = self._cache.get('hostmask')
+        if x is None:
+            x = IPAddress(int(self.netmask) ^ self._ALL_ONES,
+                          version=self._version)
+            self._cache['hostmask'] = x
+        return x
+
+    @property
+    def with_prefixlen(self):
+        return '%s/%d' % (str(self.ip), self._prefixlen)
+
+    @property
+    def with_netmask(self):
+        return '%s/%s' % (str(self.ip), str(self.netmask))
+
+    @property
+    def with_hostmask(self):
+        return '%s/%s' % (str(self.ip), str(self.hostmask))
+
+    @property
+    def numhosts(self):
+        """Number of hosts in the current subnet."""
+        return int(self.broadcast) - int(self.network) + 1
+
+    @property
+    def version(self):
+        raise NotImplementedError('BaseNet has no version')
+
+    @property
+    def prefixlen(self):
+        return self._prefixlen
+
+    def address_exclude(self, other):
+        """Remove an address from a larger block.
+
+        For example:
+
+            addr1 = IPNetwork('10.1.1.0/24')
+            addr2 = IPNetwork('10.1.1.0/26')
+            addr1.address_exclude(addr2) =
+                [IPNetwork('10.1.1.64/26'), IPNetwork('10.1.1.128/25')]
+
+        or IPv6:
+
+            addr1 = IPNetwork('::1/32')
+            addr2 = IPNetwork('::1/128')
+            addr1.address_exclude(addr2) = [IPNetwork('::0/128'),
+                IPNetwork('::2/127'),
+                IPNetwork('::4/126'),
+                IPNetwork('::8/125'),
+                ...
+                IPNetwork('0:0:8000::/33')]
+
+        Args:
+            other: An IPvXNetwork object of the same type.
+
+        Returns:
+            A sorted list of IPvXNetwork objects addresses which is self
+            minus other.
+
+        Raises:
+            TypeError: If self and other are of difffering address
+              versions, or if other is not a network object.
+            ValueError: If other is not completely contained by self.
+
+        """
+        if not self._version == other._version:
+            raise TypeError("%s and %s are not of the same version" % (
+                str(self), str(other)))
+
+        if not isinstance(other, _BaseNet):
+            raise TypeError("%s is not a network object" % str(other))
+
+        if other not in self:
+            raise ValueError('%s not contained in %s' % (str(other),
+                                                         str(self)))
+        if other == self:
+            return []
+
+        ret_addrs = []
+
+        # Make sure we're comparing the network of other.
+        other = IPNetwork('%s/%s' % (str(other.network), str(other.prefixlen)),
+                   version=other._version)
+
+        s1, s2 = self.subnet()
+        while s1 != other and s2 != other:
+            if other in s1:
+                ret_addrs.append(s2)
+                s1, s2 = s1.subnet()
+            elif other in s2:
+                ret_addrs.append(s1)
+                s1, s2 = s2.subnet()
+            else:
+                # If we got here, there's a bug somewhere.
+                assert True == False, ('Error performing exclusion: '
+                                       's1: %s s2: %s other: %s' %
+                                       (str(s1), str(s2), str(other)))
+        if s1 == other:
+            ret_addrs.append(s2)
+        elif s2 == other:
+            ret_addrs.append(s1)
+        else:
+            # If we got here, there's a bug somewhere.
+            assert True == False, ('Error performing exclusion: '
+                                   's1: %s s2: %s other: %s' %
+                                   (str(s1), str(s2), str(other)))
+
+        return sorted(ret_addrs, key=_BaseNet._get_networks_key)
+
+    def compare_networks(self, other):
+        """Compare two IP objects.
+
+        This is only concerned about the comparison of the integer
+        representation of the network addresses.  This means that the
+        host bits aren't considered at all in this method.  If you want
+        to compare host bits, you can easily enough do a
+        'HostA._ip < HostB._ip'
+
+        Args:
+            other: An IP object.
+
+        Returns:
+            If the IP versions of self and other are the same, returns:
+
+            -1 if self < other:
+              eg: IPv4('1.1.1.0/24') < IPv4('1.1.2.0/24')
+              IPv6('1080::200C:417A') < IPv6('1080::200B:417B')
+            0 if self == other
+              eg: IPv4('1.1.1.1/24') == IPv4('1.1.1.2/24')
+              IPv6('1080::200C:417A/96') == IPv6('1080::200C:417B/96')
+            1 if self > other
+              eg: IPv4('1.1.1.0/24') > IPv4('1.1.0.0/24')
+              IPv6('1080::1:200C:417A/112') >
+              IPv6('1080::0:200C:417A/112')
+
+            If the IP versions of self and other are different, returns:
+
+            -1 if self._version < other._version
+              eg: IPv4('10.0.0.1/24') < IPv6('::1/128')
+            1 if self._version > other._version
+              eg: IPv6('::1/128') > IPv4('255.255.255.0/24')
+
+        """
+        if self._version < other._version:
+            return -1
+        if self._version > other._version:
+            return 1
+        # self._version == other._version below here:
+        if self.network < other.network:
+            return -1
+        if self.network > other.network:
+            return 1
+        # self.network == other.network below here:
+        if self.netmask < other.netmask:
+            return -1
+        if self.netmask > other.netmask:
+            return 1
+        # self.network == other.network and self.netmask == other.netmask
+        return 0
+
+    def _get_networks_key(self):
+        """Network-only key function.
+
+        Returns an object that identifies this address' network and
+        netmask. This function is a suitable "key" argument for sorted()
+        and list.sort().
+
+        """
+        return (self._version, self.network, self.netmask)
+
+    def _ip_int_from_prefix(self, prefixlen=None):
+        """Turn the prefix length netmask into a int for comparison.
+
+        Args:
+            prefixlen: An integer, the prefix length.
+
+        Returns:
+            An integer.
+
+        """
+        if not prefixlen and prefixlen != 0:
+            prefixlen = self._prefixlen
+        return self._ALL_ONES ^ (self._ALL_ONES >> prefixlen)
+
+    def _prefix_from_ip_int(self, ip_int, mask=32):
+        """Return prefix length from the decimal netmask.
+
+        Args:
+            ip_int: An integer, the IP address.
+            mask: The netmask.  Defaults to 32.
+
+        Returns:
+            An integer, the prefix length.
+
+        """
+        while mask:
+            if ip_int & 1 == 1:
+                break
+            ip_int >>= 1
+            mask -= 1
+
+        return mask
+
+    def _ip_string_from_prefix(self, prefixlen=None):
+        """Turn a prefix length into a dotted decimal string.
+
+        Args:
+            prefixlen: An integer, the netmask prefix length.
+
+        Returns:
+            A string, the dotted decimal netmask string.
+
+        """
+        if not prefixlen:
+            prefixlen = self._prefixlen
+        return self._string_from_ip_int(self._ip_int_from_prefix(prefixlen))
+
+    def iter_subnets(self, prefixlen_diff=1, new_prefix=None):
+        """The subnets which join to make the current subnet.
+
+        In the case that self contains only one IP
+        (self._prefixlen == 32 for IPv4 or self._prefixlen == 128
+        for IPv6), return a list with just ourself.
+
+        Args:
+            prefixlen_diff: An integer, the amount the prefix length
+              should be increased by. This should not be set if
+              new_prefix is also set.
+            new_prefix: The desired new prefix length. This must be a
+              larger number (smaller prefix) than the existing prefix.
+              This should not be set if prefixlen_diff is also set.
+
+        Returns:
+            An iterator of IPv(4|6) objects.
+
+        Raises:
+            ValueError: The prefixlen_diff is too small or too large.
+                OR
+            prefixlen_diff and new_prefix are both set or new_prefix
+              is a smaller number than the current prefix (smaller
+              number means a larger network)
+
+        """
+        if self._prefixlen == self._max_prefixlen:
+            yield self
+            return
+
+        if new_prefix is not None:
+            if new_prefix < self._prefixlen:
+                raise ValueError('new prefix must be longer')
+            if prefixlen_diff != 1:
+                raise ValueError('cannot set prefixlen_diff and new_prefix')
+            prefixlen_diff = new_prefix - self._prefixlen
+
+        if prefixlen_diff < 0:
+            raise ValueError('prefix length diff must be > 0')
+        new_prefixlen = self._prefixlen + prefixlen_diff
+
+        if not self._is_valid_netmask(str(new_prefixlen)):
+            raise ValueError(
+                'prefix length diff %d is invalid for netblock %s' % (
+                    new_prefixlen, str(self)))
+
+        first = IPNetwork('%s/%s' % (str(self.network),
+                                     str(self._prefixlen + prefixlen_diff)),
+                         version=self._version)
+
+        yield first
+        current = first
+        while True:
+            broadcast = current.broadcast
+            if broadcast == self.broadcast:
+                return
+            new_addr = IPAddress(int(broadcast) + 1, version=self._version)
+            current = IPNetwork('%s/%s' % (str(new_addr), str(new_prefixlen)),
+                                version=self._version)
+
+            yield current
+
+    def masked(self):
+        """Return the network object with the host bits masked out."""
+        return IPNetwork('%s/%d' % (self.network, self._prefixlen),
+                         version=self._version)
+
+    def subnet(self, prefixlen_diff=1, new_prefix=None):
+        """Return a list of subnets, rather than an iterator."""
+        return list(self.iter_subnets(prefixlen_diff, new_prefix))
+
+    def supernet(self, prefixlen_diff=1, new_prefix=None):
+        """The supernet containing the current network.
+
+        Args:
+            prefixlen_diff: An integer, the amount the prefix length of
+              the network should be decreased by.  For example, given a
+              /24 network and a prefixlen_diff of 3, a supernet with a
+              /21 netmask is returned.
+
+        Returns:
+            An IPv4 network object.
+
+        Raises:
+            ValueError: If self.prefixlen - prefixlen_diff < 0. I.e., you have a
+              negative prefix length.
+                OR
+            If prefixlen_diff and new_prefix are both set or new_prefix is a
+              larger number than the current prefix (larger number means a
+              smaller network)
+
+        """
+        if self._prefixlen == 0:
+            return self
+
+        if new_prefix is not None:
+            if new_prefix > self._prefixlen:
+                raise ValueError('new prefix must be shorter')
+            if prefixlen_diff != 1:
+                raise ValueError('cannot set prefixlen_diff and new_prefix')
+            prefixlen_diff = self._prefixlen - new_prefix
+
+
+        if self.prefixlen - prefixlen_diff < 0:
+            raise ValueError(
+                'current prefixlen is %d, cannot have a prefixlen_diff of %d' %
+                (self.prefixlen, prefixlen_diff))
+        return IPNetwork('%s/%s' % (str(self.network),
+                                    str(self.prefixlen - prefixlen_diff)),
+                         version=self._version)
+
+    # backwards compatibility
+    Subnet = subnet
+    Supernet = supernet
+    AddressExclude = address_exclude
+    CompareNetworks = compare_networks
+    Contains = __contains__
+
+
+class _BaseV4(object):
+
+    """Base IPv4 object.
+
+    The following methods are used by IPv4 objects in both single IP
+    addresses and networks.
+
+    """
+
+    # Equivalent to 255.255.255.255 or 32 bits of 1's.
+    _ALL_ONES = (2**IPV4LENGTH) - 1
+    _DECIMAL_DIGITS = frozenset('0123456789')
+
+    def __init__(self, address):
+        self._version = 4
+        self._max_prefixlen = IPV4LENGTH
+
+    def _explode_shorthand_ip_string(self, ip_str=None):
+        if not ip_str:
+            ip_str = str(self)
+        return ip_str
+
+    def _ip_int_from_string(self, ip_str):
+        """Turn the given IP string into an integer for comparison.
+
+        Args:
+            ip_str: A string, the IP ip_str.
+
+        Returns:
+            The IP ip_str as an integer.
+
+        Raises:
+            AddressValueError: if ip_str isn't a valid IPv4 Address.
+
+        """
+        octets = ip_str.split('.')
+        if len(octets) != 4:
+            raise AddressValueError(ip_str)
+
+        packed_ip = 0
+        for oc in octets:
+            try:
+                packed_ip = (packed_ip << 8) | self._parse_octet(oc)
+            except ValueError:
+                raise AddressValueError(ip_str)
+        return packed_ip
+
+    def _parse_octet(self, octet_str):
+        """Convert a decimal octet into an integer.
+
+        Args:
+            octet_str: A string, the number to parse.
+
+        Returns:
+            The octet as an integer.
+
+        Raises:
+            ValueError: if the octet isn't strictly a decimal from [0..255].
+
+        """
+        # Whitelist the characters, since int() allows a lot of bizarre stuff.
+        if not self._DECIMAL_DIGITS.issuperset(octet_str):
+            raise ValueError
+        octet_int = int(octet_str, 10)
+        # Disallow leading zeroes, because no clear standard exists on
+        # whether these should be interpreted as decimal or octal.
+        if octet_int > 255 or (octet_str[0] == '0' and len(octet_str) > 1):
+            raise ValueError
+        return octet_int
+
+    def _string_from_ip_int(self, ip_int):
+        """Turns a 32-bit integer into dotted decimal notation.
+
+        Args:
+            ip_int: An integer, the IP address.
+
+        Returns:
+            The IP address as a string in dotted decimal notation.
+
+        """
+        octets = []
+        for _ in xrange(4):
+            octets.insert(0, str(ip_int & 0xFF))
+            ip_int >>= 8
+        return '.'.join(octets)
+
+    @property
+    def max_prefixlen(self):
+        return self._max_prefixlen
+
+    @property
+    def packed(self):
+        """The binary representation of this address."""
+        return v4_int_to_packed(self._ip)
+
+    @property
+    def version(self):
+        return self._version
+
+    @property
+    def is_reserved(self):
+       """Test if the address is otherwise IETF reserved.
+
+        Returns:
+            A boolean, True if the address is within the
+            reserved IPv4 Network range.
+
+       """
+       return self in IPv4Network('240.0.0.0/4')
+
+    @property
+    def is_private(self):
+        """Test if this address is allocated for private networks.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 1918.
+
+        """
+        return (self in IPv4Network('10.0.0.0/8') or
+                self in IPv4Network('172.16.0.0/12') or
+                self in IPv4Network('192.168.0.0/16'))
+
+    @property
+    def is_multicast(self):
+        """Test if the address is reserved for multicast use.
+
+        Returns:
+            A boolean, True if the address is multicast.
+            See RFC 3171 for details.
+
+        """
+        return self in IPv4Network('224.0.0.0/4')
+
+    @property
+    def is_unspecified(self):
+        """Test if the address is unspecified.
+
+        Returns:
+            A boolean, True if this is the unspecified address as defined in
+            RFC 5735 3.
+
+        """
+        return self in IPv4Network('0.0.0.0')
+
+    @property
+    def is_loopback(self):
+        """Test if the address is a loopback address.
+
+        Returns:
+            A boolean, True if the address is a loopback per RFC 3330.
+
+        """
+        return self in IPv4Network('127.0.0.0/8')
+
+    @property
+    def is_link_local(self):
+        """Test if the address is reserved for link-local.
+
+        Returns:
+            A boolean, True if the address is link-local per RFC 3927.
+
+        """
+        return self in IPv4Network('169.254.0.0/16')
+
+
+class IPv4Address(_BaseV4, _BaseIP):
+
+    """Represent and manipulate single IPv4 Addresses."""
+
+    def __init__(self, address):
+
+        """
+        Args:
+            address: A string or integer representing the IP
+              '192.168.1.1'
+
+              Additionally, an integer can be passed, so
+              IPv4Address('192.168.1.1') == IPv4Address(3232235777).
+              or, more generally
+              IPv4Address(int(IPv4Address('192.168.1.1'))) ==
+                IPv4Address('192.168.1.1')
+
+        Raises:
+            AddressValueError: If ipaddr isn't a valid IPv4 address.
+
+        """
+        _BaseIP.__init__(self, address)
+        _BaseV4.__init__(self, address)
+
+        # Efficient constructor from integer.
+        if isinstance(address, (int, long)):
+            self._ip = address
+            if address < 0 or address > self._ALL_ONES:
+                raise AddressValueError(address)
+            return
+
+        # Constructing from a packed address
+        if _compat_has_real_bytes:
+            if isinstance(address, bytes) and len(address) == 4:
+                self._ip = struct.unpack('!I', address)[0]
+                return
+
+        # Assume input argument to be string or any object representation
+        # which converts into a formatted IP string.
+        addr_str = str(address)
+        self._ip = self._ip_int_from_string(addr_str)
+
+
+class IPv4Network(_BaseV4, _BaseNet):
+
+    """This class represents and manipulates 32-bit IPv4 networks.
+
+    Attributes: [examples for IPv4Network('1.2.3.4/27')]
+        ._ip: 16909060
+        .ip: IPv4Address('1.2.3.4')
+        .network: IPv4Address('1.2.3.0')
+        .hostmask: IPv4Address('0.0.0.31')
+        .broadcast: IPv4Address('1.2.3.31')
+        .netmask: IPv4Address('255.255.255.224')
+        .prefixlen: 27
+
+    """
+
+    # the valid octets for host and netmasks. only useful for IPv4.
+    _valid_mask_octets = set((255, 254, 252, 248, 240, 224, 192, 128, 0))
+
+    def __init__(self, address, strict=False):
+        """Instantiate a new IPv4 network object.
+
+        Args:
+            address: A string or integer representing the IP [& network].
+              '192.168.1.1/24'
+              '192.168.1.1/255.255.255.0'
+              '192.168.1.1/0.0.0.255'
+              are all functionally the same in IPv4. Similarly,
+              '192.168.1.1'
+              '192.168.1.1/255.255.255.255'
+              '192.168.1.1/32'
+              are also functionaly equivalent. That is to say, failing to
+              provide a subnetmask will create an object with a mask of /32.
+
+              If the mask (portion after the / in the argument) is given in
+              dotted quad form, it is treated as a netmask if it starts with a
+              non-zero field (e.g. /255.0.0.0 == /8) and as a hostmask if it
+              starts with a zero field (e.g. 0.255.255.255 == /8), with the
+              single exception of an all-zero mask which is treated as a
+              netmask == /0. If no mask is given, a default of /32 is used.
+
+              Additionally, an integer can be passed, so
+              IPv4Network('192.168.1.1') == IPv4Network(3232235777).
+              or, more generally
+              IPv4Network(int(IPv4Network('192.168.1.1'))) ==
+                IPv4Network('192.168.1.1')
+
+            strict: A boolean. If true, ensure that we have been passed
+              A true network address, eg, 192.168.1.0/24 and not an
+              IP address on a network, eg, 192.168.1.1/24.
+
+        Raises:
+            AddressValueError: If ipaddr isn't a valid IPv4 address.
+            NetmaskValueError: If the netmask isn't valid for
+              an IPv4 address.
+            ValueError: If strict was True and a network address was not
+              supplied.
+
+        """
+        _BaseNet.__init__(self, address)
+        _BaseV4.__init__(self, address)
+
+        # Efficient constructor from integer.
+        if isinstance(address, (int, long)):
+            self._ip = address
+            self.ip = IPv4Address(self._ip)
+            self._prefixlen = self._max_prefixlen
+            self.netmask = IPv4Address(self._ALL_ONES)
+            if address < 0 or address > self._ALL_ONES:
+                raise AddressValueError(address)
+            return
+
+        # Constructing from a packed address
+        if _compat_has_real_bytes:
+            if isinstance(address, bytes) and len(address) == 4:
+                self._ip = struct.unpack('!I', address)[0]
+                self.ip = IPv4Address(self._ip)
+                self._prefixlen = self._max_prefixlen
+                self.netmask = IPv4Address(self._ALL_ONES)
+                return
+
+        # Assume input argument to be string or any object representation
+        # which converts into a formatted IP prefix string.
+        addr = str(address).split('/')
+
+        if len(addr) > 2:
+            raise AddressValueError(address)
+
+        self._ip = self._ip_int_from_string(addr[0])
+        self.ip = IPv4Address(self._ip)
+
+        if len(addr) == 2:
+            mask = addr[1].split('.')
+            if len(mask) == 4:
+                # We have dotted decimal netmask.
+                if self._is_valid_netmask(addr[1]):
+                    self.netmask = IPv4Address(self._ip_int_from_string(
+                            addr[1]))
+                elif self._is_hostmask(addr[1]):
+                    self.netmask = IPv4Address(
+                        self._ip_int_from_string(addr[1]) ^ self._ALL_ONES)
+                else:
+                    raise NetmaskValueError('%s is not a valid netmask'
+                                                     % addr[1])
+
+                self._prefixlen = self._prefix_from_ip_int(int(self.netmask))
+            else:
+                # We have a netmask in prefix length form.
+                if not self._is_valid_netmask(addr[1]):
+                    raise NetmaskValueError(addr[1])
+                self._prefixlen = int(addr[1])
+                self.netmask = IPv4Address(self._ip_int_from_prefix(
+                    self._prefixlen))
+        else:
+            self._prefixlen = self._max_prefixlen
+            self.netmask = IPv4Address(self._ip_int_from_prefix(
+                self._prefixlen))
+        if strict:
+            if self.ip != self.network:
+                raise ValueError('%s has host bits set' %
+                                 self.ip)
+
+    def _is_hostmask(self, ip_str):
+        """Test if the IP string is a hostmask (rather than a netmask).
+
+        Args:
+            ip_str: A string, the potential hostmask.
+
+        Returns:
+            A boolean, True if the IP string is a hostmask.
+
+        """
+        bits = ip_str.split('.')
+        try:
+            parts = [int(x) for x in bits if int(x) in self._valid_mask_octets]
+        except ValueError:
+            return False
+        if len(parts) != len(bits):
+            return False
+        if parts[0] < parts[-1]:
+            return True
+        return False
+
+    def _is_valid_netmask(self, netmask):
+        """Verify that the netmask is valid.
+
+        Args:
+            netmask: A string, either a prefix or dotted decimal
+              netmask.
+
+        Returns:
+            A boolean, True if the prefix represents a valid IPv4
+            netmask.
+
+        """
+        mask = netmask.split('.')
+        if len(mask) == 4:
+            if [x for x in mask if int(x) not in self._valid_mask_octets]:
+                return False
+            if [y for idx, y in enumerate(mask) if idx > 0 and
+                y > mask[idx - 1]]:
+                return False
+            return True
+        try:
+            netmask = int(netmask)
+        except ValueError:
+            return False
+        return 0 <= netmask <= self._max_prefixlen
+
+    # backwards compatibility
+    IsRFC1918 = lambda self: self.is_private
+    IsMulticast = lambda self: self.is_multicast
+    IsLoopback = lambda self: self.is_loopback
+    IsLinkLocal = lambda self: self.is_link_local
+
+
+class _BaseV6(object):
+
+    """Base IPv6 object.
+
+    The following methods are used by IPv6 objects in both single IP
+    addresses and networks.
+
+    """
+
+    _ALL_ONES = (2**IPV6LENGTH) - 1
+    _HEXTET_COUNT = 8
+    _HEX_DIGITS = frozenset('0123456789ABCDEFabcdef')
+
+    def __init__(self, address):
+        self._version = 6
+        self._max_prefixlen = IPV6LENGTH
+
+    def _ip_int_from_string(self, ip_str):
+        """Turn an IPv6 ip_str into an integer.
+
+        Args:
+            ip_str: A string, the IPv6 ip_str.
+
+        Returns:
+            A long, the IPv6 ip_str.
+
+        Raises:
+            AddressValueError: if ip_str isn't a valid IPv6 Address.
+
+        """
+        parts = ip_str.split(':')
+
+        # An IPv6 address needs at least 2 colons (3 parts).
+        if len(parts) < 3:
+            raise AddressValueError(ip_str)
+
+        # If the address has an IPv4-style suffix, convert it to hexadecimal.
+        if '.' in parts[-1]:
+            ipv4_int = IPv4Address(parts.pop())._ip
+            parts.append('%x' % ((ipv4_int >> 16) & 0xFFFF))
+            parts.append('%x' % (ipv4_int & 0xFFFF))
+
+        # An IPv6 address can't have more than 8 colons (9 parts).
+        if len(parts) > self._HEXTET_COUNT + 1:
+            raise AddressValueError(ip_str)
+
+        # Disregarding the endpoints, find '::' with nothing in between.
+        # This indicates that a run of zeroes has been skipped.
+        try:
+            skip_index, = (
+                [i for i in xrange(1, len(parts) - 1) if not parts[i]] or
+                [None])
+        except ValueError:
+            # Can't have more than one '::'
+            raise AddressValueError(ip_str)
+
+        # parts_hi is the number of parts to copy from above/before the '::'
+        # parts_lo is the number of parts to copy from below/after the '::'
+        if skip_index is not None:
+            # If we found a '::', then check if it also covers the endpoints.
+            parts_hi = skip_index
+            parts_lo = len(parts) - skip_index - 1
+            if not parts[0]:
+                parts_hi -= 1
+                if parts_hi:
+                    raise AddressValueError(ip_str)  # ^: requires ^::
+            if not parts[-1]:
+                parts_lo -= 1
+                if parts_lo:
+                    raise AddressValueError(ip_str)  # :$ requires ::$
+            parts_skipped = self._HEXTET_COUNT - (parts_hi + parts_lo)
+            if parts_skipped < 1:
+                raise AddressValueError(ip_str)
+        else:
+            # Otherwise, allocate the entire address to parts_hi.  The endpoints
+            # could still be empty, but _parse_hextet() will check for that.
+            if len(parts) != self._HEXTET_COUNT:
+                raise AddressValueError(ip_str)
+            parts_hi = len(parts)
+            parts_lo = 0
+            parts_skipped = 0
+
+        try:
+            # Now, parse the hextets into a 128-bit integer.
+            ip_int = 0L
+            for i in xrange(parts_hi):
+                ip_int <<= 16
+                ip_int |= self._parse_hextet(parts[i])
+            ip_int <<= 16 * parts_skipped
+            for i in xrange(-parts_lo, 0):
+                ip_int <<= 16
+                ip_int |= self._parse_hextet(parts[i])
+            return ip_int
+        except ValueError:
+            raise AddressValueError(ip_str)
+
+    def _parse_hextet(self, hextet_str):
+        """Convert an IPv6 hextet string into an integer.
+
+        Args:
+            hextet_str: A string, the number to parse.
+
+        Returns:
+            The hextet as an integer.
+
+        Raises:
+            ValueError: if the input isn't strictly a hex number from [0..FFFF].
+
+        """
+        # Whitelist the characters, since int() allows a lot of bizarre stuff.
+        if not self._HEX_DIGITS.issuperset(hextet_str):
+            raise ValueError
+        hextet_int = int(hextet_str, 16)
+        if hextet_int > 0xFFFF:
+            raise ValueError
+        return hextet_int
+
+    def _compress_hextets(self, hextets):
+        """Compresses a list of hextets.
+
+        Compresses a list of strings, replacing the longest continuous
+        sequence of "0" in the list with "" and adding empty strings at
+        the beginning or at the end of the string such that subsequently
+        calling ":".join(hextets) will produce the compressed version of
+        the IPv6 address.
+
+        Args:
+            hextets: A list of strings, the hextets to compress.
+
+        Returns:
+            A list of strings.
+
+        """
+        best_doublecolon_start = -1
+        best_doublecolon_len = 0
+        doublecolon_start = -1
+        doublecolon_len = 0
+        for index in range(len(hextets)):
+            if hextets[index] == '0':
+                doublecolon_len += 1
+                if doublecolon_start == -1:
+                    # Start of a sequence of zeros.
+                    doublecolon_start = index
+                if doublecolon_len > best_doublecolon_len:
+                    # This is the longest sequence of zeros so far.
+                    best_doublecolon_len = doublecolon_len
+                    best_doublecolon_start = doublecolon_start
+            else:
+                doublecolon_len = 0
+                doublecolon_start = -1
+
+        if best_doublecolon_len > 1:
+            best_doublecolon_end = (best_doublecolon_start +
+                                    best_doublecolon_len)
+            # For zeros at the end of the address.
+            if best_doublecolon_end == len(hextets):
+                hextets += ['']
+            hextets[best_doublecolon_start:best_doublecolon_end] = ['']
+            # For zeros at the beginning of the address.
+            if best_doublecolon_start == 0:
+                hextets = [''] + hextets
+
+        return hextets
+
+    def _string_from_ip_int(self, ip_int=None):
+        """Turns a 128-bit integer into hexadecimal notation.
+
+        Args:
+            ip_int: An integer, the IP address.
+
+        Returns:
+            A string, the hexadecimal representation of the address.
+
+        Raises:
+            ValueError: The address is bigger than 128 bits of all ones.
+
+        """
+        if not ip_int and ip_int != 0:
+            ip_int = int(self._ip)
+
+        if ip_int > self._ALL_ONES:
+            raise ValueError('IPv6 address is too large')
+
+        hex_str = '%032x' % ip_int
+        hextets = []
+        for x in range(0, 32, 4):
+            hextets.append('%x' % int(hex_str[x:x+4], 16))
+
+        hextets = self._compress_hextets(hextets)
+        return ':'.join(hextets)
+
+    def _explode_shorthand_ip_string(self, ip_str=None):
+        """Expand a shortened IPv6 address.
+
+        Args:
+            ip_str: A string, the IPv6 address.
+
+        Returns:
+            A string, the expanded IPv6 address.
+
+        """
+        if not ip_str:
+            ip_str = str(self)
+            if isinstance(self, _BaseNet):
+                ip_str = str(self.ip)
+
+        ip_int = self._ip_int_from_string(ip_str)
+        parts = []
+        for i in xrange(self._HEXTET_COUNT):
+            parts.append('%04x' % (ip_int & 0xFFFF))
+            ip_int >>= 16
+        parts.reverse()
+        return ':'.join(parts)
+
+    @property
+    def max_prefixlen(self):
+        return self._max_prefixlen
+
+    @property
+    def packed(self):
+        """The binary representation of this address."""
+        return v6_int_to_packed(self._ip)
+
+    @property
+    def version(self):
+        return self._version
+
+    @property
+    def is_multicast(self):
+        """Test if the address is reserved for multicast use.
+
+        Returns:
+            A boolean, True if the address is a multicast address.
+            See RFC 2373 2.7 for details.
+
+        """
+        return self in IPv6Network('ff00::/8')
+
+    @property
+    def is_reserved(self):
+        """Test if the address is otherwise IETF reserved.
+
+        Returns:
+            A boolean, True if the address is within one of the
+            reserved IPv6 Network ranges.
+
+        """
+        return (self in IPv6Network('::/8') or
+                self in IPv6Network('100::/8') or
+                self in IPv6Network('200::/7') or
+                self in IPv6Network('400::/6') or
+                self in IPv6Network('800::/5') or
+                self in IPv6Network('1000::/4') or
+                self in IPv6Network('4000::/3') or
+                self in IPv6Network('6000::/3') or
+                self in IPv6Network('8000::/3') or
+                self in IPv6Network('A000::/3') or
+                self in IPv6Network('C000::/3') or
+                self in IPv6Network('E000::/4') or
+                self in IPv6Network('F000::/5') or
+                self in IPv6Network('F800::/6') or
+                self in IPv6Network('FE00::/9'))
+
+    @property
+    def is_unspecified(self):
+        """Test if the address is unspecified.
+
+        Returns:
+            A boolean, True if this is the unspecified address as defined in
+            RFC 2373 2.5.2.
+
+        """
+        return self._ip == 0 and getattr(self, '_prefixlen', 128) == 128
+
+    @property
+    def is_loopback(self):
+        """Test if the address is a loopback address.
+
+        Returns:
+            A boolean, True if the address is a loopback address as defined in
+            RFC 2373 2.5.3.
+
+        """
+        return self._ip == 1 and getattr(self, '_prefixlen', 128) == 128
+
+    @property
+    def is_link_local(self):
+        """Test if the address is reserved for link-local.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 4291.
+
+        """
+        return self in IPv6Network('fe80::/10')
+
+    @property
+    def is_site_local(self):
+        """Test if the address is reserved for site-local.
+
+        Note that the site-local address space has been deprecated by RFC 3879.
+        Use is_private to test if this address is in the space of unique local
+        addresses as defined by RFC 4193.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 3513 2.5.6.
+
+        """
+        return self in IPv6Network('fec0::/10')
+
+    @property
+    def is_private(self):
+        """Test if this address is allocated for private networks.
+
+        Returns:
+            A boolean, True if the address is reserved per RFC 4193.
+
+        """
+        return self in IPv6Network('fc00::/7')
+
+    @property
+    def ipv4_mapped(self):
+        """Return the IPv4 mapped address.
+
+        Returns:
+            If the IPv6 address is a v4 mapped address, return the
+            IPv4 mapped address. Return None otherwise.
+
+        """
+        if (self._ip >> 32) != 0xFFFF:
+            return None
+        return IPv4Address(self._ip & 0xFFFFFFFF)
+
+    @property
+    def teredo(self):
+        """Tuple of embedded teredo IPs.
+
+        Returns:
+            Tuple of the (server, client) IPs or None if the address
+            doesn't appear to be a teredo address (doesn't start with
+            2001::/32)
+
+        """
+        if (self._ip >> 96) != 0x20010000:
+            return None
+        return (IPv4Address((self._ip >> 64) & 0xFFFFFFFF),
+                IPv4Address(~self._ip & 0xFFFFFFFF))
+
+    @property
+    def sixtofour(self):
+        """Return the IPv4 6to4 embedded address.
+
+        Returns:
+            The IPv4 6to4-embedded address if present or None if the
+            address doesn't appear to contain a 6to4 embedded address.
+
+        """
+        if (self._ip >> 112) != 0x2002:
+            return None
+        return IPv4Address((self._ip >> 80) & 0xFFFFFFFF)
+
+
+class IPv6Address(_BaseV6, _BaseIP):
+
+    """Represent and manipulate single IPv6 Addresses.
+    """
+
+    def __init__(self, address):
+        """Instantiate a new IPv6 address object.
+
+        Args:
+            address: A string or integer representing the IP
+
+              Additionally, an integer can be passed, so
+              IPv6Address('2001:4860::') ==
+                IPv6Address(42541956101370907050197289607612071936L).
+              or, more generally
+              IPv6Address(IPv6Address('2001:4860::')._ip) ==
+                IPv6Address('2001:4860::')
+
+        Raises:
+            AddressValueError: If address isn't a valid IPv6 address.
+
+        """
+        _BaseIP.__init__(self, address)
+        _BaseV6.__init__(self, address)
+
+        # Efficient constructor from integer.
+        if isinstance(address, (int, long)):
+            self._ip = address
+            if address < 0 or address > self._ALL_ONES:
+                raise AddressValueError(address)
+            return
+
+        # Constructing from a packed address
+        if _compat_has_real_bytes:
+            if isinstance(address, bytes) and len(address) == 16:
+                tmp = struct.unpack('!QQ', address)
+                self._ip = (tmp[0] << 64) | tmp[1]
+                return
+
+        # Assume input argument to be string or any object representation
+        # which converts into a formatted IP string.
+        addr_str = str(address)
+        if not addr_str:
+            raise AddressValueError('')
+
+        self._ip = self._ip_int_from_string(addr_str)
+
+
+class IPv6Network(_BaseV6, _BaseNet):
+
+    """This class represents and manipulates 128-bit IPv6 networks.
+
+    Attributes: [examples for IPv6('2001:658:22A:CAFE:200::1/64')]
+        .ip: IPv6Address('2001:658:22a:cafe:200::1')
+        .network: IPv6Address('2001:658:22a:cafe::')
+        .hostmask: IPv6Address('::ffff:ffff:ffff:ffff')
+        .broadcast: IPv6Address('2001:658:22a:cafe:ffff:ffff:ffff:ffff')
+        .netmask: IPv6Address('ffff:ffff:ffff:ffff::')
+        .prefixlen: 64
+
+    """
+
+
+    def __init__(self, address, strict=False):
+        """Instantiate a new IPv6 Network object.
+
+        Args:
+            address: A string or integer representing the IPv6 network or the IP
+              and prefix/netmask.
+              '2001:4860::/128'
+              '2001:4860:0000:0000:0000:0000:0000:0000/128'
+              '2001:4860::'
+              are all functionally the same in IPv6.  That is to say,
+              failing to provide a subnetmask will create an object with
+              a mask of /128.
+
+              Additionally, an integer can be passed, so
+              IPv6Network('2001:4860::') ==
+                IPv6Network(42541956101370907050197289607612071936L).
+              or, more generally
+              IPv6Network(IPv6Network('2001:4860::')._ip) ==
+                IPv6Network('2001:4860::')
+
+            strict: A boolean. If true, ensure that we have been passed
+              A true network address, eg, 192.168.1.0/24 and not an
+              IP address on a network, eg, 192.168.1.1/24.
+
+        Raises:
+            AddressValueError: If address isn't a valid IPv6 address.
+            NetmaskValueError: If the netmask isn't valid for
+              an IPv6 address.
+            ValueError: If strict was True and a network address was not
+              supplied.
+
+        """
+        _BaseNet.__init__(self, address)
+        _BaseV6.__init__(self, address)
+
+        # Efficient constructor from integer.
+        if isinstance(address, (int, long)):
+            self._ip = address
+            self.ip = IPv6Address(self._ip)
+            self._prefixlen = self._max_prefixlen
+            self.netmask = IPv6Address(self._ALL_ONES)
+            if address < 0 or address > self._ALL_ONES:
+                raise AddressValueError(address)
+            return
+
+        # Constructing from a packed address
+        if _compat_has_real_bytes:
+            if isinstance(address, bytes) and len(address) == 16:
+                tmp = struct.unpack('!QQ', address)
+                self._ip = (tmp[0] << 64) | tmp[1]
+                self.ip = IPv6Address(self._ip)
+                self._prefixlen = self._max_prefixlen
+                self.netmask = IPv6Address(self._ALL_ONES)
+                return
+
+        # Assume input argument to be string or any object representation
+        # which converts into a formatted IP prefix string.
+        addr = str(address).split('/')
+
+        if len(addr) > 2:
+            raise AddressValueError(address)
+
+        self._ip = self._ip_int_from_string(addr[0])
+        self.ip = IPv6Address(self._ip)
+
+        if len(addr) == 2:
+            if self._is_valid_netmask(addr[1]):
+                self._prefixlen = int(addr[1])
+            else:
+                raise NetmaskValueError(addr[1])
+        else:
+            self._prefixlen = self._max_prefixlen
+
+        self.netmask = IPv6Address(self._ip_int_from_prefix(self._prefixlen))
+
+        if strict:
+            if self.ip != self.network:
+                raise ValueError('%s has host bits set' %
+                                 self.ip)
+
+    def _is_valid_netmask(self, prefixlen):
+        """Verify that the netmask/prefixlen is valid.
+
+        Args:
+            prefixlen: A string, the netmask in prefix length format.
+
+        Returns:
+            A boolean, True if the prefix represents a valid IPv6
+            netmask.
+
+        """
+        try:
+            prefixlen = int(prefixlen)
+        except ValueError:
+            return False
+        return 0 <= prefixlen <= self._max_prefixlen
+
+    @property
+    def with_netmask(self):
+        return self.with_prefixlen