From 1cc5593892c954ffa395460e1bcbe9c34119062c Mon Sep 17 00:00:00 2001 From: Soman K S Date: Fri, 6 Nov 2020 08:59:39 +0530 Subject: [PATCH] tests: Advertise FIB installed routes to bgp peers Added test case for bgp suppress-fib-pending Updated document Signed-off-by: kssoman --- doc/user/bgp.rst | 42 +++++++ tests/topotests/bgp_suppress_fib/r1/bgpd.conf | 15 +++ .../topotests/bgp_suppress_fib/r1/zebra.conf | 9 ++ tests/topotests/bgp_suppress_fib/r2/bgpd.conf | 6 + .../topotests/bgp_suppress_fib/r2/zebra.conf | 13 ++ tests/topotests/bgp_suppress_fib/r3/bgpd.conf | 9 ++ .../bgp_suppress_fib/r3/v4_route.json | 29 +++++ .../bgp_suppress_fib/r3/v4_route2.json | 4 + .../topotests/bgp_suppress_fib/r3/zebra.conf | 6 + .../bgp_suppress_fib/test_bgp_suppress_fib.py | 119 ++++++++++++++++++ 10 files changed, 252 insertions(+) create mode 100644 tests/topotests/bgp_suppress_fib/r1/bgpd.conf create mode 100644 tests/topotests/bgp_suppress_fib/r1/zebra.conf create mode 100644 tests/topotests/bgp_suppress_fib/r2/bgpd.conf create mode 100644 tests/topotests/bgp_suppress_fib/r2/zebra.conf create mode 100644 tests/topotests/bgp_suppress_fib/r3/bgpd.conf create mode 100644 tests/topotests/bgp_suppress_fib/r3/v4_route.json create mode 100644 tests/topotests/bgp_suppress_fib/r3/v4_route2.json create mode 100644 tests/topotests/bgp_suppress_fib/r3/zebra.conf create mode 100644 tests/topotests/bgp_suppress_fib/test_bgp_suppress_fib.py diff --git a/doc/user/bgp.rst b/doc/user/bgp.rst index 3572734ba9..0089005d6f 100644 --- a/doc/user/bgp.rst +++ b/doc/user/bgp.rst @@ -3412,6 +3412,48 @@ starting the daemon and the configuration gets saved, the option will persist unless removed from the configuration with the negating command prior to the configuration write operation. +.. _bgp-suppress-fib: + +Suppressing routes not installed in FIB +======================================= + +The FRR implementation of BGP advertises prefixes learnt from a peer to other +peers even if the routes do not get installed in the FIB. There can be +scenarios where the hardware tables in some of the routers (along the path from +the source to destination) is full which will result in all routes not getting +installed in the FIB. If these routes are advertised to the downstream routers +then traffic will start flowing and will be dropped at the intermediate router. + +The solution is to provide a configurable option to check for the FIB install +status of the prefixes and advertise to peers if the prefixes are successfully +installed in the FIB. The advertisement of the prefixes are suppressed if it is +not installed in FIB. + +The following conditions apply will apply when checking for route installation +status in FIB: +1. The advertisement or suppression of routes based on FIB install status + applies only for newly learnt routes from peer (routes which are not in + BGP local RIB). +2. If the route received from peer already exists in BGP local RIB and route + attributes have changed (best path changed), the old path is deleted and + new path is installed in FIB. The FIB install status will not have any + effect. Therefore only when the route is received first time the checks + apply. +3. The feature will not apply for routes learnt through other means like + redistribution to bgp from other protocols. This is applicable only to + peer learnt routes. +4. If a route is installed in FIB and then gets deleted from the dataplane, + then routes will not be withdrawn from peers. This will be considered as + dataplane issue. +5. The feature will slightly increase the time required to advertise the routes + to peers since the route install status needs to be received from the FIB +6. If routes are received by the peer before the configuration is applied, then + the bgp sessions need to be reset for the configuration to take effect. +7. If the route which is already installed in dataplane is removed for some + reason, sending withdraw message to peers is not currently supported. + +.. index:: [no] bgp suppress-fib-pending +.. clicmd:: [no] bgp suppress-fib-pending .. _routing-policy: diff --git a/tests/topotests/bgp_suppress_fib/r1/bgpd.conf b/tests/topotests/bgp_suppress_fib/r1/bgpd.conf new file mode 100644 index 0000000000..69c563d37c --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r1/bgpd.conf @@ -0,0 +1,15 @@ +! exit1 +router bgp 1 + no bgp ebgp-requires-policy + neighbor 10.0.0.2 remote-as 2 + + address-family ipv4 unicast + redistribute static + neighbor 10.0.0.2 route-map rmap out + exit-address-family + +ip prefix-list plist seq 5 permit any + +route-map rmap permit 1 + match ip address prefix-list plist +! diff --git a/tests/topotests/bgp_suppress_fib/r1/zebra.conf b/tests/topotests/bgp_suppress_fib/r1/zebra.conf new file mode 100644 index 0000000000..7b442164ff --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r1/zebra.conf @@ -0,0 +1,9 @@ +! exit1 +interface r1-eth0 + ip address 10.0.0.1/30 +! +ip forwarding +! +ip route 40.0.0.0/8 blackhole +ip route 50.0.0.0/8 blackhole +! diff --git a/tests/topotests/bgp_suppress_fib/r2/bgpd.conf b/tests/topotests/bgp_suppress_fib/r2/bgpd.conf new file mode 100644 index 0000000000..8321c915e3 --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r2/bgpd.conf @@ -0,0 +1,6 @@ +! +router bgp 2 + no bgp ebgp-requires-policy + bgp suppress-fib-pending + neighbor 10.0.0.1 remote-as 1 + neighbor 10.0.0.10 remote-as 3 diff --git a/tests/topotests/bgp_suppress_fib/r2/zebra.conf b/tests/topotests/bgp_suppress_fib/r2/zebra.conf new file mode 100644 index 0000000000..443fffc703 --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r2/zebra.conf @@ -0,0 +1,13 @@ +! +interface r2-eth0 + ip address 10.0.0.2/30 +! +interface r2-eth1 + ip address 10.0.0.9/30 + +access-list access seq 5 permit 40.0.0.0/8 + +route-map LIMIT permit 10 + match ip address access + +ip protocol bgp route-map LIMIT diff --git a/tests/topotests/bgp_suppress_fib/r3/bgpd.conf b/tests/topotests/bgp_suppress_fib/r3/bgpd.conf new file mode 100644 index 0000000000..11715d45d7 --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r3/bgpd.conf @@ -0,0 +1,9 @@ +! +router bgp 3 + no bgp ebgp-requires-policy + neighbor 10.0.0.9 remote-as 2 + +route-map rmap permit 1 + match ip address prefix-list plist + ! +! diff --git a/tests/topotests/bgp_suppress_fib/r3/v4_route.json b/tests/topotests/bgp_suppress_fib/r3/v4_route.json new file mode 100644 index 0000000000..19294eb492 --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r3/v4_route.json @@ -0,0 +1,29 @@ +{ + "40.0.0.0\/8":[ + { + "prefix":"40.0.0.0\/8", + "protocol":"bgp", + "selected":true, + "destSelected":true, + "distance":20, + "metric":0, + "installed":true, + "table":254, + "internalStatus":16, + "internalFlags":8, + "internalNextHopNum":1, + "internalNextHopActiveNum":1, + "nexthops":[ + { + "flags":3, + "fib":true, + "ip":"10.0.0.9", + "afi":"ipv4", + "interfaceIndex":2, + "interfaceName":"r3-eth0", + "active":true + } + ] + } + ] +} diff --git a/tests/topotests/bgp_suppress_fib/r3/v4_route2.json b/tests/topotests/bgp_suppress_fib/r3/v4_route2.json new file mode 100644 index 0000000000..a35d49e9e8 --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r3/v4_route2.json @@ -0,0 +1,4 @@ +{ + "0.0.0.0\/0":[ + ] +} diff --git a/tests/topotests/bgp_suppress_fib/r3/zebra.conf b/tests/topotests/bgp_suppress_fib/r3/zebra.conf new file mode 100644 index 0000000000..793b043a7b --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/r3/zebra.conf @@ -0,0 +1,6 @@ +! +interface r3-eth0 + ip address 10.0.0.10/30 +! +ip forwarding +! diff --git a/tests/topotests/bgp_suppress_fib/test_bgp_suppress_fib.py b/tests/topotests/bgp_suppress_fib/test_bgp_suppress_fib.py new file mode 100644 index 0000000000..cf8be5f44f --- /dev/null +++ b/tests/topotests/bgp_suppress_fib/test_bgp_suppress_fib.py @@ -0,0 +1,119 @@ +#!/usr/bin/env python + +# +# test_bgp_suppress_fib.py +# +# Copyright (c) 2019 by +# +# 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. +# + +""" +""" + +import os +import sys +import json +import time +import pytest +from functools import partial +from time import sleep + +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 +from lib.topolog import logger +from mininet.topo import Topo + + +class TemplateTopo(Topo): + def build(self, *_args, **_opts): + tgen = get_topogen(self) + + 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 = tgen.add_switch("s2") + switch.add_link(tgen.gears["r2"]) + switch.add_link(tgen.gears["r3"]) + +def setup_module(mod): + tgen = Topogen(TemplateTopo, 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_route(): + tgen = get_topogen() + + if tgen.routers_have_failure(): + pytest.skip(tgen.errors) + + r3 = tgen.gears["r3"] + + sleep(5) + + json_file = "{}/r3/v4_route.json".format(CWD) + expected = json.loads(open(json_file).read()) + + test_func = partial( + topotest.router_json_cmp, + r3, + "show ip route 40.0.0.0 json", + expected, + ) + _, result = topotest.run_and_expect(test_func, None, count=2, wait=0.5) + assertmsg = '"r3" JSON output mismatches' + assert result is None, assertmsg + + json_file = "{}/r3/v4_route2.json".format(CWD) + expected = json.loads(open(json_file).read()) + + test_func = partial( + topotest.router_json_cmp, + r3, + "show ip route 50.0.0.0 json", + expected, + ) + _, result = topotest.run_and_expect(test_func, None, count=3, wait=0.5) + assertmsg = '"r3" JSON output mismatches' + assert result is None, assertmsg + +if __name__ == "__main__": + args = ["-s"] + sys.argv[1:] + sys.exit(pytest.main(args)) -- 2.39.5