tests/topotests/bgp_community_change_update/test_bgp_community_change_update.py

   1 #!/usr/bin/env python
   2
   3 # Copyright (c) 2020 by
   4 # Donatas Abraitis <donatas.abraitis@gmail.com>
   5 #
   6 # Permission to use, copy, modify, and/or distribute this software
   7 # for any purpose with or without fee is hereby granted, provided
   8 # that the above copyright notice and this permission notice appear
   9 # in all copies.
  10 #
  11 # THE SOFTWARE IS PROVIDED "AS IS" AND NETDEF DISCLAIMS ALL WARRANTIES
  12 # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13 # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
  14 # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
  15 # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  16 # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  17 # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  18 # OF THIS SOFTWARE.
  19 #
  20
  21 r"""
  22 Reference: https://www.cmand.org/communityexploration
  23
  24                      --y2--
  25                     /  |   \
  26   c1 ---- x1 ---- y1   |   z1
  27                     \  |   /
  28                      --y3--
  29
  30 1. z1 announces 192.168.255.254/32 to y2, y3.
  31 2. y2 and y3 tags this prefix at ingress with appropriate
  32 communities 65004:2 (y2) and 65004:3 (y3).
  33 3. x1 filters all communities at the egress to c1.
  34 4. Shutdown the link between y1 and y2.
  35 5. y1 will generate a BGP UPDATE message regarding the next-hop change.
  36 6. x1 will generate a BGP UPDATE message regarding community change.
  37
  38 To avoid sending duplicate BGP UPDATE messages we should make sure
  39 we send only actual route updates. In this example, x1 will skip
  40 BGP UPDATE to c1 because the actual route is the same
  41 (filtered communities - nothing changes).
  42 """
  43
  44 import os
  45 import sys
  46 import json
  47 import pytest
  48 import functools
  49
  50 CWD = os.path.dirname(os.path.realpath(__file__))
  51 sys.path.append(os.path.join(CWD, "../"))
  52
  53 # pylint: disable=C0413
  54 from lib import topotest
  55 from lib.topogen import Topogen, TopoRouter, get_topogen
  56
  57 from lib.common_config import step
  58 from time import sleep
  59
  60 pytestmark = [pytest.mark.bgpd]
  61
  62
  63 def build_topo(tgen):
  64     tgen.add_router("z1")
  65     tgen.add_router("y1")
  66     tgen.add_router("y2")
  67     tgen.add_router("y3")
  68     tgen.add_router("x1")
  69     tgen.add_router("c1")
  70
  71     # 10.0.1.0/30
  72     switch = tgen.add_switch("s1")
  73     switch.add_link(tgen.gears["c1"])
  74     switch.add_link(tgen.gears["x1"])
  75
  76     # 10.0.2.0/30
  77     switch = tgen.add_switch("s2")
  78     switch.add_link(tgen.gears["x1"])
  79     switch.add_link(tgen.gears["y1"])
  80
  81     # 10.0.3.0/30
  82     switch = tgen.add_switch("s3")
  83     switch.add_link(tgen.gears["y1"])
  84     switch.add_link(tgen.gears["y2"])
  85
  86     # 10.0.4.0/30
  87     switch = tgen.add_switch("s4")
  88     switch.add_link(tgen.gears["y1"])
  89     switch.add_link(tgen.gears["y3"])
  90
  91     # 10.0.5.0/30
  92     switch = tgen.add_switch("s5")
  93     switch.add_link(tgen.gears["y2"])
  94     switch.add_link(tgen.gears["y3"])
  95
  96     # 10.0.6.0/30
  97     switch = tgen.add_switch("s6")
  98     switch.add_link(tgen.gears["y2"])
  99     switch.add_link(tgen.gears["z1"])
 100
 101     # 10.0.7.0/30
 102     switch = tgen.add_switch("s7")
 103     switch.add_link(tgen.gears["y3"])
 104     switch.add_link(tgen.gears["z1"])
 105
 106
 107 def setup_module(mod):
 108     tgen = Topogen(build_topo, mod.__name__)
 109     tgen.start_topology()
 110
 111     router_list = tgen.routers()
 112
 113     for i, (rname, router) in enumerate(router_list.items(), 1):
 114         router.load_config(
 115             TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
 116         )
 117         router.load_config(
 118             TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
 119         )
 120
 121     tgen.start_router()
 122
 123
 124 def teardown_module(mod):
 125     tgen = get_topogen()
 126     tgen.stop_topology()
 127
 128
 129 def test_bgp_community_update_path_change():
 130     tgen = get_topogen()
 131
 132     if tgen.routers_have_failure():
 133         pytest.skip(tgen.errors)
 134
 135     def _bgp_converge_initial():
 136         output = json.loads(
 137             tgen.gears["c1"].vtysh_cmd("show ip bgp neighbor 10.0.1.2 json")
 138         )
 139         expected = {
 140             "10.0.1.2": {
 141                 "bgpState": "Established",
 142                 "addressFamilyInfo": {"ipv4Unicast": {"acceptedPrefixCounter": 8}},
 143             }
 144         }
 145         return topotest.json_cmp(output, expected)
 146
 147     step("Check if an initial topology is converged")
 148     test_func = functools.partial(_bgp_converge_initial)
 149     success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 150     assert result is None, "Failed to see bgp convergence in c1"
 151
 152     step("Disable link between y1 and y2")
 153     tgen.gears["y1"].run("ip link set dev y1-eth1 down")
 154
 155     def _bgp_converge_link_disabled():
 156         output = json.loads(tgen.gears["y1"].vtysh_cmd("show ip bgp nei 10.0.3.2 json"))
 157         expected = {"10.0.3.2": {"bgpState": "Active"}}
 158         return topotest.json_cmp(output, expected)
 159
 160     step("Check if a topology is converged after a link down between y1 and y2")
 161     test_func = functools.partial(_bgp_converge_link_disabled)
 162     success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 163     assert result is None, "Failed to see bgp convergence in y1"
 164
 165     def _bgp_check_for_duplicate_updates():
 166         duplicate = False
 167         i = 0
 168         while i < 5:
 169             if (
 170                 len(
 171                     tgen.gears["c1"].run(
 172                         'grep "10.0.1.2(x1) rcvd 192.168.255.254/32 IPv4 unicast...duplicate ignored" bgpd.log'
 173                     )
 174                 )
 175                 > 0
 176             ):
 177                 duplicate = True
 178             i += 1
 179             sleep(0.5)
 180         return duplicate
 181
 182     step("Check if we see duplicate BGP UPDATE message in c1 (suppress-duplicates)")
 183     assert (
 184         _bgp_check_for_duplicate_updates() == False
 185     ), "Seen duplicate BGP UPDATE message in c1 from x1"
 186
 187     step("Disable bgp suppress-duplicates at x1")
 188     tgen.gears["x1"].run(
 189         "vtysh -c 'conf' -c 'router bgp' -c 'no bgp suppress-duplicates'"
 190     )
 191
 192     step("Enable link between y1 and y2")
 193     tgen.gears["y1"].run("ip link set dev y1-eth1 up")
 194
 195     def _bgp_converge_link_enabled():
 196         output = json.loads(tgen.gears["y1"].vtysh_cmd("show ip bgp nei 10.0.3.2 json"))
 197         expected = {
 198             "10.0.3.2": {
 199                 "bgpState": "Established",
 200                 "addressFamilyInfo": {
 201                     "ipv4Unicast": {"acceptedPrefixCounter": 5, "sentPrefixCounter": 4}
 202                 },
 203             }
 204         }
 205         return topotest.json_cmp(output, expected)
 206
 207     step("Check if a topology is converged after a link up between y1 and y2")
 208     test_func = functools.partial(_bgp_converge_link_enabled)
 209     success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 210     assert result is None, "Failed to see bgp convergence in y1"
 211
 212     step(
 213         "Check if we see duplicate BGP UPDATE message in c1 (no bgp suppress-duplicates)"
 214     )
 215     assert (
 216         _bgp_check_for_duplicate_updates() == True
 217     ), "Didn't see duplicate BGP UPDATE message in c1 from x1"
 218
 219
 220 if __name__ == "__main__":
 221     args = ["-s"] + sys.argv[1:]
 222     sys.exit(pytest.main(args))