# Copyright 2019 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library.  If not, see <http://www.gnu.org/licenses/>.


from vyos.ifconfig.interface import Interface


class LoopbackIf(Interface):
    """
    The loopback device is a special, virtual network interface that your router
    uses to communicate with itself.
    """

    default = {
        'type': 'loopback',
    }

    def __init__(self, ifname, **kargs):
        super().__init__(ifname, **kargs)

    def remove(self):
        """
        Loopback interface can not be deleted from operating system. We can
        only remove all assigned IP addresses.

        Example:
        >>> from vyos.ifconfig import Interface
        >>> i = LoopbackIf('lo').remove()
        """
        # remove all assigned IP addresses from interface
        for addr in self.get_addr():
            if addr in ["127.0.0.1/8", "::1/128"]:
                # Do not allow deletion of the default loopback addresses as
                # this will cause weird system behavior like snmp/ssh no longer
                # operating as expected, see https://phabricator.vyos.net/T2034.
                continue

            self.del_addr(addr)