#!/usr/bin/env python3
#
# Copyright (C) 2021 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# T3619: mirror Linux Kernel defaults for ethernet offloading options into VyOS
# CLI. See https://phabricator.vyos.net/T3619#102254 for all the details.

from sys import argv

from vyos.ethtool import Ethtool
from vyos.configtree import ConfigTree

if (len(argv) < 1):
    print("Must specify file name!")
    exit(1)

file_name = argv[1]
with open(file_name, 'r') as f:
    config_file = f.read()

base = ['interfaces', 'ethernet']
config = ConfigTree(config_file)

if not config.exists(base):
    exit(0)

for ifname in config.list_nodes(base):
    eth = Ethtool(ifname)

    # If GRO is enabled by the Kernel - we reflect this on the CLI. If GRO is
    # enabled via CLI but not supported by the NIC - we remove it from the CLI
    configured = config.exists(base + [ifname, 'offload', 'gro'])
    enabled, fixed = eth.get_generic_receive_offload()
    if configured and fixed:
        config.delete(base + [ifname, 'offload', 'gro'])
    elif enabled and not fixed:
        config.set(base + [ifname, 'offload', 'gro'])

    # If GSO is enabled by the Kernel - we reflect this on the CLI. If GSO is
    # enabled via CLI but not supported by the NIC - we remove it from the CLI
    configured = config.exists(base + [ifname, 'offload', 'gso'])
    enabled, fixed = eth.get_generic_segmentation_offload()
    if configured and fixed:
        config.delete(base + [ifname, 'offload', 'gso'])
    elif enabled and not fixed:
        config.set(base + [ifname, 'offload', 'gso'])

    # If LRO is enabled by the Kernel - we reflect this on the CLI. If LRO is
    # enabled via CLI but not supported by the NIC - we remove it from the CLI
    configured = config.exists(base + [ifname, 'offload', 'lro'])
    enabled, fixed = eth.get_large_receive_offload()
    if configured and fixed:
        config.delete(base + [ifname, 'offload', 'lro'])
    elif enabled and not fixed:
        config.set(base + [ifname, 'offload', 'lro'])

    # If SG is enabled by the Kernel - we reflect this on the CLI. If SG is
    # enabled via CLI but not supported by the NIC - we remove it from the CLI
    configured = config.exists(base + [ifname, 'offload', 'sg'])
    enabled, fixed = eth.get_scatter_gather()
    if configured and fixed:
        config.delete(base + [ifname, 'offload', 'sg'])
    elif enabled and not fixed:
        config.set(base + [ifname, 'offload', 'sg'])

    # If TSO is enabled by the Kernel - we reflect this on the CLI. If TSO is
    # enabled via CLI but not supported by the NIC - we remove it from the CLI
    configured = config.exists(base + [ifname, 'offload', 'tso'])
    enabled, fixed = eth.get_tcp_segmentation_offload()
    if configured and fixed:
        config.delete(base + [ifname, 'offload', 'tso'])
    elif enabled and not fixed:
        config.set(base + [ifname, 'offload', 'tso'])

    # If UFO is enabled by the Kernel - we reflect this on the CLI. If UFO is
    # enabled via CLI but not supported by the NIC - we remove it from the CLI
    configured = config.exists(base + [ifname, 'offload', 'ufo'])
    enabled, fixed = eth.get_udp_fragmentation_offload()
    if configured and fixed:
        config.delete(base + [ifname, 'offload', 'ufo'])
    elif enabled and not fixed:
        config.set(base + [ifname, 'offload', 'ufo'])

try:
    with open(file_name, 'w') as f:
        f.write(config.to_string())
except OSError as e:
    print("Failed to save the modified config: {}".format(e))
    exit(1)