tests/topotests/bgp_path_selection/test_bgp_path_selection.py

   1 #!/usr/bin/env python
   2 # SPDX-License-Identifier: ISC
   3
   4 #
   5 # Copyright (c) 2022 by
   6 # Louis Scalbert <louis.scalbert@6wind.com>
   7 #
   8
   9 """
  10
  11 """
  12
  13 import os
  14 import sys
  15 import json
  16 import pytest
  17 import functools
  18
  19 CWD = os.path.dirname(os.path.realpath(__file__))
  20 sys.path.append(os.path.join(CWD, "../"))
  21
  22 # pylint: disable=C0413
  23 from lib import topotest
  24 from lib.topogen import Topogen, TopoRouter, get_topogen
  25 from lib.common_config import step
  26
  27 pytestmark = [pytest.mark.bgpd]
  28
  29
  30 def build_topo(tgen):
  31     for routern in range(1, 4):
  32         tgen.add_router("r{}".format(routern))
  33
  34     switch = tgen.add_switch("s1")
  35     switch.add_link(tgen.gears["r1"])
  36     switch.add_link(tgen.gears["r2"])
  37
  38     switch = tgen.add_switch("s2")
  39     switch.add_link(tgen.gears["r1"])
  40     switch.add_link(tgen.gears["r3"])
  41
  42
  43 def setup_module(mod):
  44     tgen = Topogen(build_topo, mod.__name__)
  45     tgen.start_topology()
  46
  47     router_list = tgen.routers()
  48
  49     for routern in range(1, 4):
  50         tgen.gears["r{}".format(routern)].cmd("ip link add vrf1 type vrf table 10")
  51         tgen.gears["r{}".format(routern)].cmd("ip link set vrf1 up")
  52         tgen.gears["r{}".format(routern)].cmd("ip address add dev vrf1 {}.{}.{}.{}/32".format(routern, routern, routern,routern))
  53     tgen.gears["r2"].cmd("ip address add dev vrf1 192.0.2.8/32")
  54     tgen.gears["r3"].cmd("ip address add dev vrf1 192.0.2.8/32")
  55
  56     for i, (rname, router) in enumerate(router_list.items(), 1):
  57         router.load_config(
  58             TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
  59         )
  60         router.load_config(
  61             TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
  62         )
  63         router.load_config(
  64             TopoRouter.RD_LDP, os.path.join(CWD, "{}/ldpd.conf".format(rname))
  65         )
  66
  67     tgen.start_router()
  68
  69     tgen.gears["r1"].cmd("ip route add 192.0.2.2 via 192.168.1.2 metric 20")
  70     tgen.gears["r1"].cmd("ip route add 192.0.2.3 via 192.168.2.2 metric 20")
  71
  72
  73 def teardown_module(mod):
  74     tgen = get_topogen()
  75     tgen.stop_topology()
  76
  77 def test_bgp_path_selection_ecmp():
  78     tgen = get_topogen()
  79
  80     if tgen.routers_have_failure():
  81         pytest.skip(tgen.errors)
  82
  83     def _bgp_check_path_selection_ecmp():
  84         output = json.loads(
  85             tgen.gears["r1"].vtysh_cmd("show bgp ipv4 unicast 192.0.2.8/32 json")
  86         )
  87         expected = {
  88             "paths": [
  89                 {
  90                     "valid": True,
  91                     "aspath": {"string": "65002"},
  92                     "multipath": True,
  93                     "nexthops": [{"ip": "192.0.2.2", "metric": 20}],
  94                 },
  95                 {
  96                     "valid": True,
  97                     "aspath": {"string": "65002"},
  98                     "multipath": True,
  99                     "nexthops": [{"ip": "192.0.2.3", "metric": 20}],
 100                 }
 101             ]
 102         }
 103
 104         return topotest.json_cmp(output, expected)
 105
 106     step("Check if two ECMP paths are present")
 107     test_func = functools.partial(_bgp_check_path_selection_ecmp)
 108     _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 109     assert result is None, "Failed to see BGP prefixes on R1"
 110
 111
 112 def test_bgp_path_selection_vpn_ecmp():
 113     tgen = get_topogen()
 114
 115     if tgen.routers_have_failure():
 116         pytest.skip(tgen.errors)
 117
 118     def _bgp_check_path_selection_vpn_ecmp():
 119         output = json.loads(
 120             tgen.gears["r1"].vtysh_cmd("show bgp vrf vrf1 ipv4 unicast 192.0.2.8/32 json")
 121         )
 122         expected = {
 123             "paths": [
 124                 {
 125                     "valid": True,
 126                     "aspath": {"string": "65002"},
 127                     "multipath": True,
 128                     "nexthops": [{"ip": "192.0.2.2", "metric": 20}],
 129                 },
 130                 {
 131                     "valid": True,
 132                     "aspath": {"string": "65002"},
 133                     "multipath": True,
 134                     "nexthops": [{"ip": "192.0.2.3", "metric": 20}],
 135                 }
 136             ]
 137         }
 138
 139         return topotest.json_cmp(output, expected)
 140
 141     step("Check if two ECMP paths are present")
 142     test_func = functools.partial(_bgp_check_path_selection_vpn_ecmp)
 143     _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 144     assert result is None, "Failed to see BGP prefixes on R1"
 145
 146
 147 def test_bgp_path_selection_metric():
 148     tgen = get_topogen()
 149
 150     if tgen.routers_have_failure():
 151         pytest.skip(tgen.errors)
 152
 153     def _bgp_check_path_selection_metric():
 154         output = json.loads(
 155             tgen.gears["r1"].vtysh_cmd("show bgp ipv4 unicast 192.0.2.8/32 json")
 156         )
 157         expected = {
 158             "paths": [
 159                 {
 160                     "valid": True,
 161                     "aspath": {"string": "65002"},
 162                     "nexthops": [{"ip": "192.0.2.2", "metric": 10}],
 163                     "bestpath":{ "selectionReason":"IGP Metric"},
 164                 },
 165                 {
 166                     "valid": True,
 167                     "aspath": {"string": "65002"},
 168                     "nexthops": [{"ip": "192.0.2.3", "metric": 20}],
 169                 }
 170             ]
 171         }
 172
 173         return topotest.json_cmp(output, expected)
 174
 175     tgen.gears["r1"].cmd("ip route add 192.0.2.2 via 192.168.1.2 metric 10")
 176     tgen.gears["r1"].cmd("ip route del 192.0.2.2 via 192.168.1.2 metric 20")
 177
 178     step("Check if IGP metric best path is selected")
 179     test_func = functools.partial(_bgp_check_path_selection_metric)
 180     _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 181     assert result is None, "Failed to see BGP prefixes on R1"
 182
 183
 184 def test_bgp_path_selection_vpn_metric():
 185     tgen = get_topogen()
 186
 187     if tgen.routers_have_failure():
 188         pytest.skip(tgen.errors)
 189
 190     def _bgp_check_path_selection_vpn_metric():
 191         output = json.loads(
 192             tgen.gears["r1"].vtysh_cmd("show bgp vrf vrf1 ipv4 unicast 192.0.2.8/32 json")
 193         )
 194         expected = {
 195             "paths": [
 196                 {
 197                     "valid": True,
 198                     "aspath": {"string": "65002"},
 199                     "nexthops": [{"ip": "192.0.2.2", "metric": 10}],
 200                     "bestpath":{ "selectionReason":"IGP Metric"},
 201                 },
 202                 {
 203                     "valid": True,
 204                     "aspath": {"string": "65002"},
 205                     "nexthops": [{"ip": "192.0.2.3", "metric": 20}],
 206                 }
 207             ]
 208         }
 209
 210         return topotest.json_cmp(output, expected)
 211
 212     step("Check if IGP metric best path is selected")
 213     test_func = functools.partial(_bgp_check_path_selection_vpn_metric)
 214     _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 215     assert result is None, "Failed to see BGP prefixes on R1"
 216
 217
 218 if __name__ == "__main__":
 219     args = ["-s"] + sys.argv[1:]
 220     sys.exit(pytest.main(args))