#!/usr/bin/env python
# SPDX-License-Identifier: ISC
#
# Copyright (c) 2019 by VMware, Inc. ("VMware")
# Used Copyright (c) 2018 by Network Device Education Foundation, Inc. ("NetDEF")
# in this file.
#

"""
Following tests are covered to test BGP Graceful Restart functionality.
Basic Common Test steps for all the test case below :
- Create topology (setup module)
  Creating 2 routers topology, r1, r2 in IBGP
- Bring up topology
- Verify for bgp to converge
- Configure BGP Garceful Restart on both the routers.

1. Transition from Peer-level helper to Global Restarting
2. Transition from Peer-level helper to Global inherit helper
3. Transition from Peer-level restarting to Global inherit helper
4. Default GR functional mode is Helper.
5. Verify that the restarting node sets "R" bit while sending the
   BGP open messages after the node restart, only if GR is enabled.
6. Verify if restarting node resets R bit in BGP open message
   during normal BGP session flaps as well, even when GR restarting
   mode is enabled. Here link flap happen due to interface UP/DOWN.
7. Verify if restarting node resets R bit in BGP
   open message during normal BGP session flaps when GR is disabled.
8. Verify that restarting nodes set "F" bit while sending
   the BGP open messages after it restarts, only when BGP GR is enabled.
9. Verify that only GR helper routers keep the stale
   route entries, not any GR disabled router.
10. Verify that GR helper routers keeps all the routes received
    from restarting node if both the routers are configured as
    GR restarting node.
11. Verify that GR helper routers delete all the routes
    received from a node if both the routers are configured as GR
    helper node.
12. After BGP neighborship is established and GR capability is exchanged,
    transition restarting router to disabled state and vice versa.
13. After BGP neighborship is established and GR capability is exchanged,
    transition restarting router to disabled state and vice versa.
14. Verify that restarting nodes reset "F" bit while sending
    the BGP open messages after it's restarts, when BGP GR is **NOT** enabled.
15. Verify that only GR helper routers keep the stale
    route entries, not any GR disabled router.
16. Transition from Global Restarting to Disable and then Global
    Disable to Restarting.
17. Transition from Global Helper to Disable and then Global
    Disable to Helper.
18. Transition from Global Restart to Helper and then Global
    Helper to Restart, Global Mode : GR Restarting
    PerPeer Mode :  GR Helper
    GR Mode effective : GR Helper
19. Transition from Peer-level helper to Global Restarting,
    Global Mode : GR Restarting
    PerPeer Mode :  GR Restarting
    GR Mode effective : GR Restarting
20. Transition from Peer-level restart to Global Restart
    Global Mode : GR Restarting
    PerPeer Mode :  GR Restarting
    GR Mode effective : GR Restarting
21. Transition from Peer-level disabled to Global Restart
    Global Mode : GR Restarting
    PerPeer Mode : GR Disabled
    GR Mode effective : GR Disabled
22. Peer-level inherit from Global Restarting
    Global Mode : GR Restart
    PerPeer Mode :  None
    GR Mode effective : GR Restart
23. Transition from Peer-level disable to Global inherit helper
    Global Mode : None
    PerPeer Mode :  GR Disable
    GR Mode effective : GR Disable

These tests have been broken up into 4 sub python scripts because
the totality of this run was fairly significant.
"""

import os
import sys
import time
import pytest

# Save the Current Working Directory to find configuration files.
CWD = os.path.dirname(os.path.realpath(__file__))
sys.path.append(os.path.join("../"))
sys.path.append(os.path.join("../lib/"))

# pylint: disable=C0413
# Import topogen and topotest helpers
from lib.topogen import Topogen, get_topogen
from lib.topolog import logger

# Required to instantiate the topology builder class.

# Import topoJson from lib, to create topology and initial configuration
from lib.topojson import build_config_from_json
from lib.bgp import (
    clear_bgp,
    verify_bgp_rib,
    verify_graceful_restart,
    create_router_bgp,
    verify_r_bit,
    verify_bgp_convergence,
    verify_bgp_convergence_from_running_config,
)

from lib.common_config import (
    write_test_header,
    reset_config_on_routers,
    start_topology,
    kill_router_daemons,
    start_router_daemons,
    verify_rib,
    check_address_types,
    write_test_footer,
    check_router_status,
    shutdown_bringup_interface,
    step,
    get_frr_ipv6_linklocal,
    required_linux_kernel_version,
)

pytestmark = [pytest.mark.bgpd]


# Global variables
NEXT_HOP_IP = {"ipv4": "192.168.1.10", "ipv6": "fd00:0:0:1::10"}
NEXT_HOP_IP_1 = {"ipv4": "192.168.0.1", "ipv6": "fd00::1"}
NEXT_HOP_IP_2 = {"ipv4": "192.168.0.2", "ipv6": "fd00::2"}
BGP_CONVERGENCE = False
GR_RESTART_TIMER = 20
PREFERRED_NEXT_HOP = "link_local"


def setup_module(mod):
    """
    Sets up the pytest environment

    * `mod`: module name
    """

    global ADDR_TYPES

    # Required linux kernel version for this suite to run.
    result = required_linux_kernel_version("4.16")
    if result is not True:
        pytest.skip("Kernel requirements are not met, kernel version should be >=4.16")

    testsuite_run_time = time.asctime(time.localtime(time.time()))
    logger.info("Testsuite start time: {}".format(testsuite_run_time))
    logger.info("=" * 40)

    logger.info("Running setup_module to create topology")

    # This function initiates the topology build with Topogen...
    json_file = "{}/bgp_gr_topojson_topo1.json".format(CWD)
    tgen = Topogen(json_file, mod.__name__)
    global topo
    topo = tgen.json_topo
    # ... and here it calls Mininet initialization functions.

    # Starting topology, create tmp files which are loaded to routers
    #  to start daemons and then start routers
    start_topology(tgen)

    # Creating configuration from JSON
    build_config_from_json(tgen, topo)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Api call verify whether BGP is converged
    ADDR_TYPES = check_address_types()

    BGP_CONVERGENCE = verify_bgp_convergence(tgen, topo)
    assert BGP_CONVERGENCE is True, "setup_module : Failed \n Error:" " {}".format(
        BGP_CONVERGENCE
    )

    logger.info("Running setup_module() done")


def teardown_module(mod):
    """
    Teardown the pytest environment

    * `mod`: module name
    """

    logger.info("Running teardown_module to delete topology")

    tgen = get_topogen()

    # Stop toplogy and Remove tmp files
    tgen.stop_topology()

    logger.info(
        "Testsuite end time: {}".format(time.asctime(time.localtime(time.time())))
    )
    logger.info("=" * 40)


def configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut, peer):
    """
    This function groups the repetitive function calls into one function.
    """

    result = create_router_bgp(tgen, topo, input_dict)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    for addr_type in ADDR_TYPES:
        neighbor = topo["routers"][peer]["links"]["r1-link1"][addr_type].split("/")[0]
        clear_bgp(tgen, addr_type, dut, neighbor=neighbor)

    for addr_type in ADDR_TYPES:
        neighbor = topo["routers"][dut]["links"]["r2-link1"][addr_type].split("/")[0]
        clear_bgp(tgen, addr_type, peer, neighbor=neighbor)

    result = verify_bgp_convergence_from_running_config(tgen)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    return True


def next_hop_per_address_family(
    tgen, dut, peer, addr_type, next_hop_dict, preferred_next_hop=PREFERRED_NEXT_HOP
):
    """
    This function returns link_local or global next_hop per address-family
    """

    intferface = topo["routers"][peer]["links"]["{}-link1".format(dut)]["interface"]
    if addr_type == "ipv6" and "link_local" in preferred_next_hop:
        next_hop = get_frr_ipv6_linklocal(tgen, peer, intf=intferface)
    else:
        next_hop = next_hop_dict[addr_type]

    return next_hop


def BGP_GR_TC_50_p1(request):
    """
    Test Objective : Transition from Peer-level helper to Global inherit helper
    Global Mode : None
    PerPeer Mode :  Helper
    GR Mode effective : GR Helper

    """

    tgen = get_topogen()
    tc_name = request.node.name
    write_test_header(tc_name)

    # Check router status
    check_router_status(tgen)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Creating configuration from JSON
    reset_config_on_routers(tgen)

    step(
        "Configure R1 as GR helper node at per Peer-level for R2"
        " and configure R2 as global restarting node."
    )

    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
        "r2": {"bgp": {"graceful-restart": {"graceful-restart": True}}},
    }

    configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut="r1", peer="r2")

    step("Verify on R2 that R1 advertises GR capabilities as a helper node")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    step("Kill BGP on R2")

    kill_router_daemons(tgen, "r2", ["bgpd"])

    step(
        "Verify that R2 keeps the stale entries in FIB & R1 keeps stale entries in RIB & FIB"
    )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    step("Bring up BGP on R2 and remove Peer-level GR config from R1 ")

    start_router_daemons(tgen, "r2", ["bgpd"])

    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-helper": False}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-helper": False}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        }
    }

    result = create_router_bgp(tgen, topo, input_dict)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    for addr_type in ADDR_TYPES:
        neighbor = topo["routers"]["r2"]["links"]["r1-link1"][addr_type].split("/")[0]
        clear_bgp(tgen, addr_type, "r1", neighbor=neighbor)

    result = verify_bgp_convergence_from_running_config(tgen)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    step("Verify on R2 that R1 still advertises GR capabilities as a helper node")

    input_dict = {
        "r1": {"bgp": {"graceful-restart": {"graceful-restart-helper": True}}},
        "r2": {"bgp": {"graceful-restart": {"graceful-restart": True}}},
    }

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    step("Kill BGP on R2")

    kill_router_daemons(tgen, "r2", ["bgpd"])

    step(
        "Verify that R2 keeps the stale entries in FIB & R1 keeps stale entries in RIB & FIB"
    )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    step("Start BGP on R2")

    start_router_daemons(tgen, "r2", ["bgpd"])

    write_test_footer(tc_name)


def test_BGP_GR_TC_51_p1(request):
    """
    Test Objective : Transition from Peer-level restarting to Global inherit helper
    Global Mode : None
    PerPeer Mode :  GR Restart
    GR Mode effective : GR Restart

    """

    tgen = get_topogen()
    tc_name = request.node.name
    write_test_header(tc_name)

    # Check router status
    check_router_status(tgen)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Creating configuration from JSON
    reset_config_on_routers(tgen)

    step("Configure R1 as GR restarting node at per Peer-level for R2")

    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
        "r2": {"bgp": {"graceful-restart": {"graceful-restart": True}}},
    }

    configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut="r1", peer="r2")
    step("Verify on R2 that R1 advertises GR capabilities as a restarting node")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_bgp_rib(tgen, addr_type, "r2", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    step("Kill BGP on R1")

    kill_router_daemons(tgen, "r1", ["bgpd"])

    step(
        "Verify that R1 keeps the stale entries in FIB & R2 keeps stale entries in RIB & FIB"
    )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_bgp_rib(tgen, addr_type, "r2", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    step("Bring up BGP on R1 and remove Peer-level GR config")

    start_router_daemons(tgen, "r1", ["bgpd"])

    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": False}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": False}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        }
    }

    result = create_router_bgp(tgen, topo, input_dict)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    for addr_type in ADDR_TYPES:
        neighbor = topo["routers"]["r2"]["links"]["r1-link1"][addr_type].split("/")[0]
        clear_bgp(tgen, addr_type, "r1", neighbor=neighbor)

    result = verify_bgp_convergence_from_running_config(tgen)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    step("Verify on R2 that R1 advertises GR capabilities as a helper node")

    input_dict = {
        "r1": {"bgp": {"graceful-restart": {"graceful-restart-helper": True}}},
        "r2": {"bgp": {"graceful-restart": {"graceful-restart": True}}},
    }

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    step("Kill BGPd on R2")

    kill_router_daemons(tgen, "r2", ["bgpd"])

    step(
        "Verify that R2 keeps the stale entries in FIB & R1 keeps stale entries in RIB & FIB"
    )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert (
            result is True
        ), "Testcase {} : Failed \n Routes are still present \n Error {}".format(
            tc_name, result
        )

    step("Start BGP on R2")

    start_router_daemons(tgen, "r2", ["bgpd"])

    write_test_footer(tc_name)


def test_BGP_GR_TC_53_p1(request):
    """
    Test Objective : Default GR functional mode is Helper.
    Global Mode : None
    PerPeer Mode :  None
    GR Mode effective : GR Helper

    """

    tgen = get_topogen()
    tc_name = request.node.name
    write_test_header(tc_name)

    # Check router status
    check_router_status(tgen)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Creating configuration from JSON
    reset_config_on_routers(tgen)

    step("configure R2 as global restarting node")

    input_dict = {"r2": {"bgp": {"graceful-restart": {"graceful-restart": True}}}}

    configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut="r1", peer="r2")

    step(
        "Verify on R2 that R1 advertises GR capabilities as a helper node based on inherit"
    )

    input_dict = {
        "r1": {"bgp": {"graceful-restart": {"graceful-restart-helper": True}}},
        "r2": {"bgp": {"graceful-restart": {"graceful-restart": True}}},
    }

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    step("Kill BGPd on R2")

    kill_router_daemons(tgen, "r2", ["bgpd"])

    step(
        "Verify that R2 keeps the stale entries in FIB & R1 keeps stale entries in RIB & FIB"
    )

    for addr_type in ADDR_TYPES:
        protocol = "bgp"
        next_hop = next_hop_per_address_family(
            tgen, "r2", "r1", addr_type, NEXT_HOP_IP_1
        )
        input_topo = {"r1": topo["routers"]["r1"]}
        result = verify_rib(tgen, addr_type, "r2", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    for addr_type in ADDR_TYPES:
        next_hop = next_hop_per_address_family(
            tgen, "r1", "r2", addr_type, NEXT_HOP_IP_2
        )
        input_topo = {"r2": topo["routers"]["r2"]}
        result = verify_bgp_rib(tgen, addr_type, "r1", input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_rib(tgen, addr_type, "r1", input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    step("Start BGP on R2")

    start_router_daemons(tgen, "r2", ["bgpd"])

    write_test_footer(tc_name)


def test_BGP_GR_TC_4_p0(request):
    """
    Test Objective : Verify that the restarting node sets "R" bit while sending the
    BGP open messages after the node restart, only if GR is enabled.
    """

    tgen = get_topogen()
    tc_name = request.node.name
    write_test_header(tc_name)

    # Check router status
    check_router_status(tgen)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Creating configuration from JSON
    reset_config_on_routers(tgen)

    logger.info(
        "[Phase 1] : Test Setup" " [Restart Mode]R1-----R2[Helper Mode] initialized  "
    )

    # Configure graceful-restart
    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
        "r2": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
    }

    configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut="r1", peer="r2")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying BGP RIB routes
        dut = "r1"
        peer = "r2"
        next_hop = next_hop_per_address_family(
            tgen, dut, peer, addr_type, NEXT_HOP_IP_2
        )
        input_topo = {key: topo["routers"][key] for key in ["r2"]}
        result = verify_bgp_rib(tgen, addr_type, dut, input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying RIB routes
        protocol = "bgp"
        result = verify_rib(tgen, addr_type, dut, input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    logger.info("[Phase 2] : R2 goes for reload  ")

    kill_router_daemons(tgen, "r2", ["bgpd"])

    logger.info(
        "[Phase 3] : R2 is still down, restart time {} sec."
        "So time verify the routes are present in BGP RIB and ZEBRA ".format(
            GR_RESTART_TIMER
        )
    )

    for addr_type in ADDR_TYPES:
        # Verifying BGP RIB routes
        next_hop = next_hop_per_address_family(
            tgen, dut, peer, addr_type, NEXT_HOP_IP_2
        )
        input_topo = {key: topo["routers"][key] for key in ["r2"]}
        result = verify_bgp_rib(
            tgen, addr_type, dut, input_topo, next_hop, expected=False
        )
        assert result is not True, (
            "Testcase {} : Failed \n "
            "Expected: Routes should not be present in {} BGP RIB \n "
            "Found: {}".format(tc_name, dut, result)
        )

        # Verifying RIB routes
        result = verify_rib(
            tgen, addr_type, dut, input_topo, next_hop, protocol, expected=False
        )
        assert result is not True, (
            "Testcase {} : Failed \n "
            "Expected: Routes should not be present in {} FIB \n "
            "Found: {}".format(tc_name, dut, result)
        )

    logger.info("[Phase 5] : R2 is about to come up now  ")
    start_router_daemons(tgen, "r2", ["bgpd"])

    logger.info("[Phase 4] : R2 is UP now, so time to collect GR stats  ")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_r_bit(tgen, topo, addr_type, input_dict, dut="r1", peer="r2")
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying BGP RIB routes
        next_hop = next_hop_per_address_family(
            tgen, dut, peer, addr_type, NEXT_HOP_IP_2
        )
        input_topo = {key: topo["routers"][key] for key in ["r2"]}
        result = verify_bgp_rib(tgen, addr_type, dut, input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying RIB routes
        result = verify_rib(tgen, addr_type, dut, input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    write_test_footer(tc_name)


def test_BGP_GR_TC_5_1_2_p1(request):
    """
    Test Objective : Verify if restarting node resets R bit in BGP open message
    during normal BGP session flaps as well, even when GR restarting mode is enabled.
    Here link flap happen due to interface UP/DOWN.

    """
    tgen = get_topogen()
    tc_name = request.node.name
    write_test_header(tc_name)

    # Check router status
    check_router_status(tgen)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Creating configuration from JSON
    reset_config_on_routers(tgen)

    logger.info(
        "[Phase 1] : Test Setup" " [Restart Mode]R1-----R2[Restart Mode] initialized  "
    )

    # Configure graceful-restart
    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
        "r2": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
    }

    configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut="r1", peer="r2")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying BGP RIB routes
        dut = "r1"
        peer = "r2"
        next_hop = next_hop_per_address_family(
            tgen, dut, peer, addr_type, NEXT_HOP_IP_2
        )
        input_topo = {key: topo["routers"][key] for key in ["r2"]}
        result = verify_bgp_rib(tgen, addr_type, dut, input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying RIB routes
        protocol = "bgp"
        result = verify_rib(tgen, addr_type, dut, input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    logger.info("[Phase 2] : Now flap the link running the BGP session  ")
    # Shutdown interface
    intf = "r2-r1-eth0"
    shutdown_bringup_interface(tgen, "r2", intf)

    # Bring up Interface
    shutdown_bringup_interface(tgen, "r2", intf, ifaceaction=True)

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_r_bit(tgen, topo, addr_type, input_dict, dut="r1", peer="r2")
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    logger.info("[Phase 2] : Restart BGPd on router R2.  ")
    kill_router_daemons(tgen, "r2", ["bgpd"])

    start_router_daemons(tgen, "r2", ["bgpd"])

    logger.info("[Phase 4] : R2 is UP now, so time to collect GR stats  ")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_r_bit(tgen, topo, addr_type, input_dict, dut="r1", peer="r2")
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying BGP RIB routes
        next_hop = next_hop_per_address_family(
            tgen, dut, peer, addr_type, NEXT_HOP_IP_2
        )
        input_topo = {key: topo["routers"][key] for key in ["r2"]}
        result = verify_bgp_rib(tgen, addr_type, dut, input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying RIB routes
        result = verify_rib(tgen, addr_type, dut, input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    write_test_footer(tc_name)


def test_BGP_GR_TC_6_1_2_p1(request):
    """
    Test Objective : Verify if restarting node resets R bit in BGP
    open message during normal BGP session flaps when GR is disabled.
    """

    tgen = get_topogen()
    tc_name = request.node.name
    write_test_header(tc_name)

    # Check router status
    check_router_status(tgen)

    # Don't run this test if we have any failure.
    if tgen.routers_have_failure():
        pytest.skip(tgen.errors)

    # Creating configuration from JSON
    reset_config_on_routers(tgen)

    logger.info(
        "[Phase 1] : Test Setup" "[Restart Mode]R1-----R2[Helper Mode] initialized  "
    )

    # Configure graceful-restart
    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
        "r2": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
    }

    configure_gr_followed_by_clear(tgen, topo, input_dict, tc_name, dut="r1", peer="r2")

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying BGP RIB routes
        dut = "r1"
        peer = "r2"
        next_hop = next_hop_per_address_family(
            tgen, dut, peer, addr_type, NEXT_HOP_IP_2
        )
        input_topo = {key: topo["routers"][key] for key in ["r2"]}
        result = verify_bgp_rib(tgen, addr_type, dut, input_topo, next_hop)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        # Verifying RIB routes
        protocol = "bgp"
        result = verify_rib(tgen, addr_type, dut, input_topo, next_hop, protocol)
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    logger.info("[Phase 1] : Changing mode" "[Disable Mode]R1-----R2[Helper Mode]")

    # Configure graceful-restart
    input_dict = {
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-disable": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-disable": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        }
    }

    result = create_router_bgp(tgen, topo, input_dict)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    for addr_type in ADDR_TYPES:
        neighbor = topo["routers"]["r2"]["links"]["r1-link1"][addr_type].split("/")[0]
        clear_bgp(tgen, addr_type, "r1", neighbor=neighbor)

    result = verify_bgp_convergence_from_running_config(tgen)
    assert result is True, "Testcase {} : Failed \n Error: {}".format(tc_name, result)

    # Verify GR stats
    input_dict = {
        "r2": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r1": {
                                    "dest_link": {
                                        "r2-link1": {"graceful-restart-helper": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
        "r1": {
            "bgp": {
                "address_family": {
                    "ipv4": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-disable": True}
                                    }
                                }
                            }
                        }
                    },
                    "ipv6": {
                        "unicast": {
                            "neighbor": {
                                "r2": {
                                    "dest_link": {
                                        "r1-link1": {"graceful-restart-disable": True}
                                    }
                                }
                            }
                        }
                    },
                }
            }
        },
    }

    # here the verify_graceful_restart fro the neighbor would be
    # "NotReceived" as the latest GR config is not yet applied.
    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

    logger.info("[Phase 2] : Now flap the link running the BGP session  ")
    # Shutdown interface
    intf = "r2-r1-eth0"
    shutdown_bringup_interface(tgen, "r2", intf)

    # Bring up Interface
    shutdown_bringup_interface(tgen, "r2", intf, ifaceaction=True)

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_r_bit(
            tgen, topo, addr_type, input_dict, dut="r2", peer="r1", expected=False
        )
        assert result is not True, (
            "Testcase {} : Failed \n "
            "Expected: R-bit should not be set to True in r2\n"
            "Found: {}".format(tc_name, result)
        )

    logger.info("Restart BGPd on R2 ")
    kill_router_daemons(tgen, "r2", ["bgpd"])

    start_router_daemons(tgen, "r2", ["bgpd"])

    for addr_type in ADDR_TYPES:
        result = verify_graceful_restart(
            tgen, topo, addr_type, input_dict, dut="r1", peer="r2"
        )
        assert result is True, "Testcase {} : Failed \n Error {}".format(
            tc_name, result
        )

        result = verify_r_bit(
            tgen, topo, addr_type, input_dict, dut="r2", peer="r1", expected=False
        )
        assert result is not True, (
            "Testcase {} : Failed \n "
            "Expected: R-bit should not be set to True in r2\n"
            "Found: {}".format(tc_name, result)
        )

    write_test_footer(tc_name)


if __name__ == "__main__":
    args = ["-s"] + sys.argv[1:]
    sys.exit(pytest.main(args))
