#!/usr/bin/env python

#
# test_ospf_suppres_fa.py
# Carles Kishimoto
#
# Permission to use, copy, modify, and/or distribute this software
# for any purpose with or without fee is hereby granted, provided
# that the above copyright notice and this permission notice appear
# in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NETDEF DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
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# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
# OF THIS SOFTWARE.
#

"""
test_ospf_suppres_fa.py: Test OSPF suppress-fa feature
- Topology: r1 --- R2 (ABR) --- R3 (redistribute static)

test_ospf_set_suppress_fa()
    1) R1: Get a dict[LSA_ID] = fwd_addr for all type 5 LSA
    2) R2: Configure: area 1 nssa suppress-fa
    3) R1: Get a dict[LSA_ID] and compare fwd_address with 0.0.0.0

test_ospf_unset_suppress_fa()
    4) R2: Configure: no area 1 nssa suppress-fa
    5) R1: Get a dict[LSA_ID] = fwd_addr and compare it with the dict obtained in 1)
"""

import os
import sys
import re
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(CWD, "../"))

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

# Required to instantiate the topology builder class.

pytestmark = [pytest.mark.ospfd]


def build_topo(tgen):
    "Build function"

    # Create routers
    for router in range(1, 4):
        tgen.add_router("r{}".format(router))

    # R1-R2 backbone area
    switch = tgen.add_switch("s1")
    switch.add_link(tgen.gears["r1"])
    switch.add_link(tgen.gears["r2"])

    # R2-R3 NSSA area
    switch = tgen.add_switch("s2")
    switch.add_link(tgen.gears["r2"])
    switch.add_link(tgen.gears["r3"])


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

    tgen = Topogen(build_topo, mod.__name__)
    tgen.start_topology()

    # This is a sample of configuration loading.
    router_list = tgen.routers()

    # For all registered routers, load the zebra and ospf configuration file
    for rname, router in router_list.items():
        router.load_config(
            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
        )
        router.load_config(
            TopoRouter.RD_OSPF, os.path.join(CWD, "{}/ospfd.conf".format(rname))
        )

    tgen.start_router()


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

    tgen = get_topogen()
    tgen.stop_topology()


def test_converge_protocols():
    "Wait for protocol convergence"

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

    topotest.sleep(10, "Waiting for OSPF convergence")


def ospf_configure_suppress_fa(router_name, area):
    "Configure OSPF suppress-fa in router_name"

    tgen = get_topogen()
    router = tgen.gears[router_name]
    router.vtysh_cmd(
        "conf t\nrouter ospf\narea {} nssa suppress-fa\nexit\n".format(area)
    )


def ospf_unconfigure_suppress_fa(router_name, area):
    "Remove OSPF suppress-fa in router_name"

    tgen = get_topogen()
    router = tgen.gears[router_name]
    router.vtysh_cmd(
        "conf t\nrouter ospf\nno area {} nssa suppress-fa\nexit\n".format(area)
    )


def ospf_get_lsa_type5(router_name):
    "Return a dict with link state id as key and forwarding addresses as value"

    result = dict()
    tgen = get_topogen()
    router = tgen.gears[router_name]
    cmd = "show ip ospf database external\n"
    output = topotest.normalize_text(router.vtysh_cmd(cmd))
    for line in output.splitlines():
        re0 = re.match(r"\s+Link State ID: (\S+) \(External Network Number\)", line)
        if re0:
            lsa = re0.group(1)
        re1 = re.match(r"\s+Forward Address: (\S+)", line)
        if re1:
            result[lsa] = re1.group(1)
    return result


@pytest.fixture(scope="module", name="original")
def test_ospf_set_suppress_fa():
    "Test OSPF area [x] nssa suppress-fa"

    # Get current forwarding address for each LSA type-5 in r1
    initial = ospf_get_lsa_type5("r1")

    # Configure suppres-fa in r2 area 1
    ospf_configure_suppress_fa("r2", "1")
    topotest.sleep(10, "Waiting for OSPF convergence")

    # Check forwarding address on r1 for all statics is 0.0.0.0
    assertmsg = "Forwarding address is not 0.0.0.0 after enabling OSPF suppress-fa"
    suppress = ospf_get_lsa_type5("r1")
    for prefix in suppress:
        assert suppress[prefix] == "0.0.0.0", assertmsg

    # Return the original forwarding addresses so we can compare them
    # in the test_ospf_unset_supress_fa
    return initial


def test_ospf_unset_supress_fa(original):
    "Test OSPF no area [x] nssa suppress-fa"

    # Remove suppress-fa in r2 area 1
    ospf_unconfigure_suppress_fa("r2", "1")
    topotest.sleep(10, "Waiting for OSPF convergence")

    # Check forwarding address is the original value on r1 for all statics
    assertmsg = "Forwarding address is not correct after removing OSPF suppress-fa"
    restore = ospf_get_lsa_type5("r1")
    for prefix in restore:
        assert restore[prefix] == original[prefix], assertmsg


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