Synnefo

import ipaddr

from synnefo.settings import MAX_CIDR_BLOCK

def validate_network_params(subnet=None, gateway=None, subnet6=None,

                            gateway6=None):

    if (subnet is None) and (subnet6 is None):

        raise faults.BadRequest("subnet or subnet6 is required")

    if subnet:

        try:

            # Use strict option to not all subnets with host bits set

            network = ipaddr.IPv4Network(subnet, strict=True)

        except ValueError:

            raise faults.BadRequest("Invalid network IPv4 subnet")

        # Check that network size is allowed!

        if not validate_network_size(network.prefixlen):

            raise faults.OverLimit(message="Unsupported network size",

                                   details="Network mask must be in range"

                                           " (%s, 29]" % MAX_CIDR_BLOCK)

        if gateway:  # Check that gateway belongs to network

            try:

                gateway = ipaddr.IPv4Address(gateway)

            except ValueError:

                raise faults.BadRequest("Invalid network IPv4 gateway")

            if not gateway in network:

                raise faults.BadRequest("Invalid network IPv4 gateway")

    if subnet6:

        try:

            # Use strict option to not all subnets with host bits set

            network6 = ipaddr.IPv6Network(subnet6, strict=True)

        except ValueError:

            raise faults.BadRequest("Invalid network IPv6 subnet")

        if gateway6:

            try:

                gateway6 = ipaddr.IPv6Address(gateway6)

            except ValueError:

                raise faults.BadRequest("Invalid network IPv6 gateway")

            if not gateway6 in network6:

                raise faults.BadRequest("Invalid network IPv6 gateway")

def validate_network_size(cidr_block):

    """Return True if network size is allowed."""

    return cidr_block <= 29 and cidr_block > MAX_CIDR_BLOCK