#!/usr/bin/env python3
#
# Copyright (C) 2020-2022 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/>.

import re
import os
import json
import unittest

from base_vyostest_shim import VyOSUnitTestSHIM

from netifaces import interfaces

from vyos.configsession import ConfigSessionError
from vyos.ifconfig import Interface
from vyos.ifconfig import Section
from vyos.template import is_ipv6
from vyos.template import is_ipv4
from vyos.util import cmd
from vyos.util import read_file
from vyos.util import get_interface_config
from vyos.validate import is_intf_addr_assigned

base_path = ['vrf']
vrfs = ['red', 'green', 'blue', 'foo-bar', 'baz_foo']

def get_vrf_ipv4_routes(vrf):
    return json.loads(cmd(f'ip -4 -j route show vrf {vrf}'))

def get_vrf_ipv6_routes(vrf):
    return json.loads(cmd(f'ip -6 -j route show vrf {vrf}'))

class VRFTest(VyOSUnitTestSHIM.TestCase):
    _interfaces = []

    @classmethod
    def setUpClass(cls):
        # we need to filter out VLAN interfaces identified by a dot (.)
        # in their name - just in case!
        if 'TEST_ETH' in os.environ:
            tmp = os.environ['TEST_ETH'].split()
            cls._interfaces = tmp
        else:
            for tmp in Section.interfaces('ethernet'):
                if not '.' in tmp:
                    cls._interfaces.append(tmp)

        # call base-classes classmethod
        super(cls, cls).setUpClass()

    def tearDown(self):
        # delete all VRFs
        self.cli_delete(base_path)
        self.cli_delete(['interfaces', 'dummy'])
        self.cli_delete(['protocols', 'vrf'])
        self.cli_commit()
        for vrf in vrfs:
            self.assertNotIn(vrf, interfaces())

    def test_vrf_table_id(self):
        table = '1000'
        for vrf in vrfs:
            base = base_path + ['name', vrf]
            description = f'VyOS-VRF-{vrf}'
            self.cli_set(base + ['description', description])

            # check validate() - a table ID is mandatory
            with self.assertRaises(ConfigSessionError):
                self.cli_commit()

            self.cli_set(base + ['table', table])
            if vrf == 'green':
                self.cli_set(base + ['disable'])

            table = str(int(table) + 1)

        # commit changes
        self.cli_commit()

        # Verify VRF configuration
        table = '1000'
        iproute2_config = read_file('/etc/iproute2/rt_tables.d/vyos-vrf.conf')
        for vrf in vrfs:
            description = f'VyOS-VRF-{vrf}'
            self.assertTrue(vrf in interfaces())
            vrf_if = Interface(vrf)
            # validate proper interface description
            self.assertEqual(vrf_if.get_alias(), description)
            # validate admin up/down state of VRF
            state = 'up'
            if vrf == 'green':
                state = 'down'
            self.assertEqual(vrf_if.get_admin_state(), state)

            # Test the iproute2 lookup file, syntax is as follows:
            #
            # # id       vrf name         comment
            # 1000       red              # VyOS-VRF-red
            # 1001       green            # VyOS-VRF-green
            #  ...
            regex = f'{table}\s+{vrf}\s+#\s+{description}'
            self.assertTrue(re.findall(regex, iproute2_config))

            tmp = get_interface_config(vrf)
            self.assertEqual(int(table), tmp['linkinfo']['info_data']['table'])

            # Increment table ID for the next run
            table = str(int(table) + 1)

    def test_vrf_loopbacks_ips(self):
        table = '2000'
        for vrf in vrfs:
            base = base_path + ['name', vrf]
            self.cli_set(base + ['table', str(table)])
            table = str(int(table) + 1)

        # commit changes
        self.cli_commit()

        # Verify VRF configuration
        loopbacks = ['127.0.0.1', '::1']
        for vrf in vrfs:
            # Ensure VRF was created
            self.assertIn(vrf, interfaces())
            # Test for proper loopback IP assignment
            for addr in loopbacks:
                self.assertTrue(is_intf_addr_assigned(vrf, addr))

    def test_vrf_loopbacks_no_ipv6(self):
        table = '2002'
        for vrf in vrfs:
            base = base_path + ['name', vrf]
            self.cli_set(base + ['table', str(table)])
            table = str(int(table) + 1)

        # Globally disable IPv6 - this will remove all IPv6 interface addresses
        self.cli_set(['system', 'ipv6', 'disable'])

        # commit changes
        self.cli_commit()

        # Verify VRF configuration
        table = '2002'
        loopbacks = ['127.0.0.1', '::1']
        for vrf in vrfs:
            # Ensure VRF was created
            self.assertIn(vrf, interfaces())

            # Verify VRF table ID
            tmp = get_interface_config(vrf)
            self.assertEqual(int(table), tmp['linkinfo']['info_data']['table'])

            # Test for proper loopback IP assignment
            for addr in loopbacks:
                if is_ipv4(addr):
                    self.assertTrue(is_intf_addr_assigned(vrf, addr))
                else:
                    self.assertFalse(is_intf_addr_assigned(vrf, addr))

            table = str(int(table) + 1)

        self.cli_delete(['system', 'ipv6'])

    def test_vrf_bind_all(self):
        table = '2000'
        for vrf in vrfs:
            base = base_path + ['name', vrf]
            self.cli_set(base + ['table', str(table)])
            table = str(int(table) + 1)

        self.cli_set(base_path +  ['bind-to-all'])

        # commit changes
        self.cli_commit()

        # Verify VRF configuration
        tmp = read_file('/proc/sys/net/ipv4/tcp_l3mdev_accept')
        self.assertIn(tmp, '1')
        tmp = read_file('/proc/sys/net/ipv4/udp_l3mdev_accept')
        self.assertIn(tmp, '1')

    def test_vrf_table_id_is_unalterable(self):
        # Linux Kernel prohibits the change of a VRF table  on the fly.
        # VRF must be deleted and recreated!
        table = '1000'
        vrf = vrfs[0]
        base = base_path + ['name', vrf]
        self.cli_set(base + ['table', table])

        # commit changes
        self.cli_commit()

        # Check if VRF has been created
        self.assertTrue(vrf in interfaces())

        table = str(int(table) + 1)
        self.cli_set(base + ['table', table])
        # check validate() - table ID can not be altered!
        with self.assertRaises(ConfigSessionError):
            self.cli_commit()

    def test_vrf_assign_interface(self):
        vrf = vrfs[0]
        table = '5000'
        self.cli_set(['vrf', 'name', vrf, 'table', table])

        for interface in self._interfaces:
            section = Section.section(interface)
            self.cli_set(['interfaces', section, interface, 'vrf', vrf])

        # commit changes
        self.cli_commit()

        # Verify VRF assignmant
        for interface in self._interfaces:
            tmp = get_interface_config(interface)
            self.assertEqual(vrf, tmp['master'])

            # cleanup
            section = Section.section(interface)
            self.cli_delete(['interfaces', section, interface, 'vrf'])

    def test_vrf_static_routes(self):
        routes = {
            '10.0.0.0/8' : {
                'next_hop' : '192.0.2.2',
                'distance' : '200',
                'next_hop_vrf' : 'default',
                },
            '172.16.0.0/12' : {
                'next_hop' : '192.0.2.3',
                'next_hop_vrf' : 'default',
                },
            '192.168.0.0/16' : {
                'next_hop' : '192.0.2.3',
                },
            '2001:db8:1000::/48' : {
                'next_hop' : '2001:db8::2',
                },
        }

        # required interface for leaking to default table
        self.cli_set(['interfaces', 'ethernet', 'eth0', 'address', '192.0.2.1/24'])

        table = '2000'
        for vrf in vrfs:
            base = base_path + ['name', vrf]
            self.cli_set(base + ['table', str(table)])

            # we also need an interface in "UP" state to install routes
            self.cli_set(['interfaces', 'dummy', f'dum{table}', 'vrf', vrf])
            self.cli_set(['interfaces', 'dummy', f'dum{table}', 'address', '192.0.2.1/24'])
            self.cli_set(['interfaces', 'dummy', f'dum{table}', 'address', '2001:db8::1/64'])
            table = str(int(table) + 1)

            proto_base = ['protocols', 'vrf', vrf, 'static']
            for route, route_config in routes.items():
                route_type = 'route'
                if is_ipv6(route):
                    route_type = 'route6'
                self.cli_set(proto_base + [route_type, route, 'next-hop', route_config['next_hop']])
                if 'distance' in route_config:
                    self.cli_set(proto_base + [route_type, route, 'next-hop', route_config['next_hop'], 'distance', route_config['distance']])
                if 'next_hop_vrf' in route_config:
                    self.cli_set(proto_base + [route_type, route, 'next-hop', route_config['next_hop'], 'next-hop-vrf', route_config['next_hop_vrf']])

        # commit changes
        self.cli_commit()

        # Verify routes
        for vrf in vrfs:
            self.assertIn(vrf, interfaces())
            frrconfig = self.getFRRconfig(f'vrf {vrf}')
            for prefix, prefix_config in routes.items():
                tmp = 'ip'
                if is_ipv6(prefix):
                    tmp += 'v6'

                tmp += f' route {prefix} {prefix_config["next_hop"]}'
                if 'distance' in prefix_config:
                    tmp += ' ' + prefix_config['distance']
                if 'next_hop_vrf' in prefix_config:
                    tmp += ' nexthop-vrf ' + prefix_config['next_hop_vrf']

                    self.assertIn(tmp, frrconfig)

        self.cli_delete(['interfaces', 'ethernet', 'eth0', 'address'])


    def test_vrf_link_local_ip_addresses(self):
        # Testcase for issue T4331
        table = '100'
        vrf = 'orange'
        interface = 'dum9998'
        addresses = ['192.0.2.1/26', '2001:db8:9998::1/64', 'fe80::1/64']

        for address in addresses:
            self.cli_set(['interfaces', 'dummy', interface, 'address', address])

        # Create dummy interfaces
        self.cli_commit()

        # ... and verify IP addresses got assigned
        for address in addresses:
            self.assertTrue(is_intf_addr_assigned(interface, address))

        # Move interface to VRF
        self.cli_set(base_path + ['name', vrf, 'table', table])
        self.cli_set(['interfaces', 'dummy', interface, 'vrf', vrf])

        # Apply VRF config
        self.cli_commit()
        # Ensure VRF got created
        self.assertIn(vrf, interfaces())
        # ... and IP addresses are still assigned
        for address in addresses:
            self.assertTrue(is_intf_addr_assigned(interface, address))
        # Verify VRF table ID
        tmp = get_interface_config(vrf)
        self.assertEqual(int(table), tmp['linkinfo']['info_data']['table'])

        # Verify interface is assigned to VRF
        tmp = get_interface_config(interface)
        self.assertEqual(vrf, tmp['master'])

        # Delete Interface
        self.cli_delete(['interfaces', 'dummy', interface])
        self.cli_commit()

if __name__ == '__main__':
    unittest.main(verbosity=2)