#!/usr/bin/env python3
# Copyright 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/>.
#
# T7633: This migration converts legacy 'encryption cipher' directives into
# 'encryption data-ciphers-fallback' for site-to-site mode tunnels.
#
# In modern OpenVPN (v2.6+), 'cipher' and 'data-ciphers' are not valid
# in site-to-site mode.
# The appropriate directive is now '--data-ciphers-fallback alg'.

from vyos.configtree import ConfigTree

def migrate(config: ConfigTree) -> None:
    ovpn_intfs = config.list_nodes(['interfaces', 'openvpn'], path_must_exist=False)
    for i in ovpn_intfs:
        base_path = ['interfaces', 'openvpn', i]
        mode_path = base_path + ['mode']
        cipher_path = base_path + ['encryption', 'cipher']

        # Only migrate if mode is explicitly 'site-to-site'
        if config.value_exists(mode_path, 'site-to-site'):

            # Rename 'encryption cipher' with 'encryption data-ciphers-fallback'
            if config.exists(cipher_path):
                config.rename(cipher_path, 'data-ciphers-fallback')