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#!/usr/bin/env python
# Copyright (c) 2021 by
# Donatas Abraitis <donatas.abraitis@gmail.com>
#
# 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
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
# OF THIS SOFTWARE.
#
"""
https://tools.ietf.org/html/rfc4271
Check if NEXT_HOP attribute is not changed if peer X shares a
common subnet with this address.
- Otherwise, if the route being announced was learned from an
external peer, the speaker can use an IP address of any
adjacent router (known from the received NEXT_HOP attribute)
that the speaker itself uses for local route calculation in
the NEXT_HOP attribute, provided that peer X shares a common
subnet with this address. This is a second form of "third
party" NEXT_HOP attribute.
"""
import os
import sys
import json
import pytest
import functools
pytestmark = [pytest.mark.bgpd]
CWD = os.path.dirname(os.path.realpath(__file__))
sys.path.append(os.path.join(CWD, "../"))
# pylint: disable=C0413
from lib import topotest
from lib.topogen import Topogen, TopoRouter, get_topogen
pytestmark = [pytest.mark.bgpd]
def build_topo(tgen):
for routern in range(1, 4):
tgen.add_router("r{}".format(routern))
switch = tgen.add_switch("s1")
switch.add_link(tgen.gears["r1"])
switch.add_link(tgen.gears["r2"])
switch.add_link(tgen.gears["r3"])
def setup_module(mod):
tgen = Topogen(build_topo, mod.__name__)
tgen.start_topology()
router_list = tgen.routers()
for i, (rname, router) in enumerate(router_list.items(), 1):
router.load_config(
TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
)
router.load_config(
TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
)
tgen.start_router()
def teardown_module(mod):
tgen = get_topogen()
tgen.stop_topology()
def test_bgp_ebgp_common_subnet_nh_unchanged():
tgen = get_topogen()
if tgen.routers_have_failure():
pytest.skip(tgen.errors)
r2 = tgen.gears["r2"]
r3 = tgen.gears["r3"]
def _bgp_converge(router):
output = json.loads(router.vtysh_cmd("show ip bgp summary json"))
expected = {
"ipv4Unicast": {
"peers": {
"192.168.1.1": {"state": "Established"},
"192.168.1.103": {"state": "Established"},
}
}
}
return topotest.json_cmp(output, expected)
test_func = functools.partial(_bgp_converge, r3)
success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
assert result is None, 'Failed bgp convergence in "{}"'.format(r3)
def _bgp_nh_unchanged(router):
output = json.loads(router.vtysh_cmd("show ip bgp 172.16.1.1/32 json"))
expected = {"paths": [{"nexthops": [{"ip": "192.168.1.1"}]}]}
return topotest.json_cmp(output, expected)
test_func = functools.partial(_bgp_nh_unchanged, r2)
success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
assert result is None, 'Wrong next-hop in "{}"'.format(r2)
if __name__ == "__main__":
args = ["-s"] + sys.argv[1:]
sys.exit(pytest.main(args))
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