#!/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://vyos.dev/T3619#102254 for all the details.
# T3787: Remove deprecated UDP fragmentation offloading option

from sys import argv

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

if len(argv) < 2:
    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'])

    # Remove deprecated UDP fragmentation offloading option
    if config.exists(base + [ifname, 'offload', 'ufo']):
        config.delete(base + [ifname, 'offload', 'ufo'])

    # Also while processing the interface configuration, not all adapters support
    # changing the speed and duplex settings. If the desired speed and duplex
    # values do not work for the NIC driver, we change them back to the default
    # value of "auto" - which will be applied if the CLI node is deleted.
    speed_path = base + [ifname, 'speed']
    duplex_path = base + [ifname, 'duplex']
    # speed and duplex must always be set at the same time if not set to "auto"
    if config.exists(speed_path) and config.exists(duplex_path):
        speed = config.return_value(speed_path)
        duplex = config.return_value(duplex_path)
        if speed != 'auto' and duplex != 'auto':
            if not eth.check_speed_duplex(speed, duplex):
                config.delete(speed_path)
                config.delete(duplex_path)

    # Also while processing the interface configuration, not all adapters support
    # changing disabling flow-control - or change this setting. If disabling
    # flow-control is not supported by the NIC, we remove the setting from CLI
    flow_control_path = base + [ifname, 'disable-flow-control']
    if config.exists(flow_control_path):
        if not eth.check_flow_control():
            config.delete(flow_control_path)

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)