tests/topotests/bgp_remove_private_as/test_bgp_remove_private_as.py

   1 #!/usr/bin/env python
   2 # SPDX-License-Identifier: ISC
   3
   4 #
   5 # test_bgp_remove_private_as.py
   6 #
   7 # Copyright (C) 2022  NVIDIA Corporation
   8 # Trey Aspelund
   9 #
  10
  11 """
  12 test_bgp_remove_private_as.py tests the following conditions:
  13 1. "remove-private-AS" strips all private ASNs from the AS-path unless:
  14     a. the ASN belongs to the peer
  15     b. the ASN is both local + private
  16     c. the AS-path is not completely comprised of public ASNs
  17 2. "remove-private-AS all" strips all private ASNs from the AS-path unless:
  18     a. the ASN belongs to the peer
  19     b. the ASN is both local + private
  20 3. "remove-private-AS replace-AS" swaps private ASNs with local ASN unless:
  21     a. the ASN belongs to the peer
  22     b. the AS-path is not completely comprised of public ASNs
  23 4. "remove-private-AS all replace-AS" swaps private ASNs with local ASN unless:
  24     a. the ASN belongs to the peer
  25
  26 All conditions are tested while the local ASN is private.
  27 All conditions are tested while the local ASN is public.
  28 All conditions are tested against an eBGP peer in a private ASN.
  29 All conditions are tested against an eBGP peer in a public ASN.
  30 """
  31
  32 import os
  33 import sys
  34 import json
  35 import time
  36 import pytest
  37
  38 CWD = os.path.dirname(os.path.realpath(__file__))
  39 sys.path.append(os.path.join(CWD, "../"))
  40
  41 # pylint: disable=C0413
  42 from lib import topotest
  43 from lib.topogen import Topogen, TopoRouter, get_topogen
  44 from functools import partial
  45
  46 pytestmark = [pytest.mark.bgpd]
  47
  48
  49 def build_topo(tgen):
  50     """
  51     We are effectively creating two hub/spoke topologies with r2 and r5 acting
  52     as hubs. "remove-private-AS" will be configured on r2/r5 towards r3/r4, and
  53     r1 will act as the originator of the test prefixes. AS-Path validation will
  54     be done on r3/r4.
  55
  56     Topology:
  57     +-----+      +-----+     +-----+
  58     | r1  |----->|r2/r5|---->| r3  |
  59     +-----+      +-----+     +-----+
  60                     |
  61                     v
  62                  +-----+
  63                  | r4  |
  64                  +-----+
  65     ASNs:
  66      - r1: 65001
  67      - r2: 65002
  68      - r3: 65003
  69      - r4: 4444
  70      - r5: 5555
  71     """
  72     for routern in range(1, 6):
  73         tgen.add_router(f"r{routern}")
  74
  75     #######################
  76     # Connections to r2
  77     #######################
  78     switch = tgen.add_switch("s1")
  79     switch.add_link(tgen.gears["r1"])
  80     switch.add_link(tgen.gears["r2"])
  81
  82     switch = tgen.add_switch("s2")
  83     switch.add_link(tgen.gears["r2"])
  84     switch.add_link(tgen.gears["r3"])
  85
  86     switch = tgen.add_switch("s3")
  87     switch.add_link(tgen.gears["r2"])
  88     switch.add_link(tgen.gears["r4"])
  89
  90     #######################
  91     # Connections to r5
  92     #######################
  93     switch = tgen.add_switch("s4")
  94     switch.add_link(tgen.gears["r1"])
  95     switch.add_link(tgen.gears["r5"])
  96
  97     switch = tgen.add_switch("s5")
  98     switch.add_link(tgen.gears["r3"])
  99     switch.add_link(tgen.gears["r5"])
 100
 101     switch = tgen.add_switch("s6")
 102     switch.add_link(tgen.gears["r4"])
 103     switch.add_link(tgen.gears["r5"])
 104
 105
 106 def setup_module(mod):
 107     tgen = Topogen(build_topo, mod.__name__)
 108     tgen.start_topology()
 109
 110     router_list = tgen.routers()
 111
 112     for i, (rname, router) in enumerate(router_list.items(), 1):
 113         router.load_config(
 114             TopoRouter.RD_ZEBRA, os.path.join(CWD, f"{rname}/zebra.conf")
 115         )
 116         router.load_config(TopoRouter.RD_BGP, os.path.join(CWD, f"{rname}/bgpd.conf"))
 117
 118     tgen.start_router()
 119
 120
 121 def teardown_module(mod):
 122     tgen = get_topogen()
 123     tgen.stop_topology()
 124
 125
 126 def test_bgp_remove_private_as():
 127     tgen = get_topogen()
 128
 129     if tgen.routers_have_failure():
 130         pytest.skip(tgen.errors)
 131
 132     # Test routes
 133     prefixes = [
 134         "100.64.0.0/32",
 135         "100.64.0.1/32",
 136         "100.64.0.2/32",
 137         "100.64.0.3/32",
 138         "100.64.0.4/32",
 139     ]
 140
 141     # r2/r5 are setup with remove-private-AS configs.
 142     tx_routers = ["r2", "r5"]
 143
 144     # We will validate the paths received by r3/r4.
 145     rx_routers = ["r3", "r4"]
 146
 147     # Config options for remove-private-AS
 148     remove_types = [
 149         "remove-private-AS",
 150         "remove-private-AS all",
 151         "remove-private-AS replace-AS",
 152         "remove-private-AS all replace-AS",
 153     ]
 154
 155     # Expected as-paths for each test route from the perspective of each
 156     # rx_router, accounting for each variation of remove-private-AS.
 157     #
 158     # Structure:
 159     # expected_paths = {
 160     #     rx_router: {
 161     #         remove_type: {
 162     #             tx_router: {
 163     #                 prefix: "path"
 164     #             }
 165     #         }
 166     #     }
 167     # }
 168     expected_paths = {
 169         "r3": {
 170             "remove-private-AS": {
 171                 "r2": {
 172                     "100.64.0.0/32": "65002",
 173                     "100.64.0.1/32": "65002 65003 65003",
 174                     "100.64.0.2/32": "65002 65001 4200000000 1000 4200000001 2000 4200000002",
 175                     "100.64.0.3/32": "65002 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 176                     "100.64.0.4/32": "65002 65001 1000 2000 2000 3000",
 177                 },
 178                 "r5": {
 179                     "100.64.0.0/32": "5555",
 180                     "100.64.0.1/32": "5555 65003 65003",
 181                     "100.64.0.2/32": "5555 65001 4200000000 1000 4200000001 2000 4200000002",
 182                     "100.64.0.3/32": "5555 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 183                     "100.64.0.4/32": "5555 65001 1000 2000 2000 3000",
 184                 },
 185             },
 186             "remove-private-AS all": {
 187                 "r2": {
 188                     "100.64.0.0/32": "65002",
 189                     "100.64.0.1/32": "65002 65003 65003",
 190                     "100.64.0.2/32": "65002 1000 2000",
 191                     "100.64.0.3/32": "65002 65003 1000 2000 65003",
 192                     "100.64.0.4/32": "65002 1000 2000 2000 3000",
 193                 },
 194                 "r5": {
 195                     "100.64.0.0/32": "5555",
 196                     "100.64.0.1/32": "5555 65003 65003",
 197                     "100.64.0.2/32": "5555 1000 2000",
 198                     "100.64.0.3/32": "5555 65003 1000 2000 65003",
 199                     "100.64.0.4/32": "5555 1000 2000 2000 3000",
 200                 },
 201             },
 202             "remove-private-AS replace-AS": {
 203                 "r2": {
 204                     "100.64.0.0/32": "65002 65002 65002 65002 65002",
 205                     "100.64.0.1/32": "65002 65002 65003 65002 65002 65002 65003",
 206                     "100.64.0.2/32": "65002 65001 4200000000 1000 4200000001 2000 4200000002",
 207                     "100.64.0.3/32": "65002 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 208                     "100.64.0.4/32": "65002 65001 1000 2000 2000 3000",
 209                 },
 210                 "r5": {
 211                     "100.64.0.0/32": "5555 5555 5555 5555 5555",
 212                     "100.64.0.1/32": "5555 5555 65003 5555 5555 5555 65003",
 213                     "100.64.0.2/32": "5555 65001 4200000000 1000 4200000001 2000 4200000002",
 214                     "100.64.0.3/32": "5555 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 215                     "100.64.0.4/32": "5555 65001 1000 2000 2000 3000",
 216                 },
 217             },
 218             "remove-private-AS all replace-AS": {
 219                 "r2": {
 220                     "100.64.0.0/32": "65002 65002 65002 65002 65002",
 221                     "100.64.0.1/32": "65002 65002 65003 65002 65002 65002 65003",
 222                     "100.64.0.2/32": "65002 65002 65002 1000 65002 2000 65002",
 223                     "100.64.0.3/32": "65002 65002 65003 65002 1000 65002 2000 65002 65003",
 224                     "100.64.0.4/32": "65002 65002 1000 2000 2000 3000",
 225                 },
 226                 "r5": {
 227                     "100.64.0.0/32": "5555 5555 5555 5555 5555",
 228                     "100.64.0.1/32": "5555 5555 65003 5555 5555 5555 65003",
 229                     "100.64.0.2/32": "5555 5555 5555 1000 5555 2000 5555",
 230                     "100.64.0.3/32": "5555 5555 65003 5555 1000 5555 2000 5555 65003",
 231                     "100.64.0.4/32": "5555 5555 1000 2000 2000 3000",
 232                 },
 233             },
 234         },
 235         "r4": {
 236             "remove-private-AS": {
 237                 "r2": {
 238                     "100.64.0.0/32": "65002",
 239                     "100.64.0.1/32": "65002",
 240                     "100.64.0.2/32": "65002 65001 4200000000 1000 4200000001 2000 4200000002",
 241                     "100.64.0.3/32": "65002 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 242                     "100.64.0.4/32": "65002 65001 1000 2000 2000 3000",
 243                 },
 244                 "r5": {
 245                     "100.64.0.0/32": "5555",
 246                     "100.64.0.1/32": "5555",
 247                     "100.64.0.2/32": "5555 65001 4200000000 1000 4200000001 2000 4200000002",
 248                     "100.64.0.3/32": "5555 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 249                     "100.64.0.4/32": "5555 65001 1000 2000 2000 3000",
 250                 },
 251             },
 252             "remove-private-AS all": {
 253                 "r2": {
 254                     "100.64.0.0/32": "65002",
 255                     "100.64.0.1/32": "65002",
 256                     "100.64.0.2/32": "65002 1000 2000",
 257                     "100.64.0.3/32": "65002 1000 2000",
 258                     "100.64.0.4/32": "65002 1000 2000 2000 3000",
 259                 },
 260                 "r5": {
 261                     "100.64.0.0/32": "5555",
 262                     "100.64.0.1/32": "5555",
 263                     "100.64.0.2/32": "5555 1000 2000",
 264                     "100.64.0.3/32": "5555 1000 2000",
 265                     "100.64.0.4/32": "5555 1000 2000 2000 3000",
 266                 },
 267             },
 268             "remove-private-AS replace-AS": {
 269                 "r2": {
 270                     "100.64.0.0/32": "65002 65002 65002 65002 65002",
 271                     "100.64.0.1/32": "65002 65002 65002 65002 65002 65002 65002",
 272                     "100.64.0.2/32": "65002 65001 4200000000 1000 4200000001 2000 4200000002",
 273                     "100.64.0.3/32": "65002 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 274                     "100.64.0.4/32": "65002 65001 1000 2000 2000 3000",
 275                 },
 276                 "r5": {
 277                     "100.64.0.0/32": "5555 5555 5555 5555 5555",
 278                     "100.64.0.1/32": "5555 5555 5555 5555 5555 5555 5555",
 279                     "100.64.0.2/32": "5555 65001 4200000000 1000 4200000001 2000 4200000002",
 280                     "100.64.0.3/32": "5555 65001 65003 4200000000 1000 4200000001 2000 4200000002 65003",
 281                     "100.64.0.4/32": "5555 65001 1000 2000 2000 3000",
 282                 },
 283             },
 284             "remove-private-AS all replace-AS": {
 285                 "r2": {
 286                     "100.64.0.0/32": "65002 65002 65002 65002 65002",
 287                     "100.64.0.1/32": "65002 65002 65002 65002 65002 65002 65002",
 288                     "100.64.0.2/32": "65002 65002 65002 1000 65002 2000 65002",
 289                     "100.64.0.3/32": "65002 65002 65002 65002 1000 65002 2000 65002 65002",
 290                     "100.64.0.4/32": "65002 65002 1000 2000 2000 3000",
 291                 },
 292                 "r5": {
 293                     "100.64.0.0/32": "5555 5555 5555 5555 5555",
 294                     "100.64.0.1/32": "5555 5555 5555 5555 5555 5555 5555",
 295                     "100.64.0.2/32": "5555 5555 5555 1000 5555 2000 5555",
 296                     "100.64.0.3/32": "5555 5555 5555 5555 1000 5555 2000 5555 5555",
 297                     "100.64.0.4/32": "5555 5555 1000 2000 2000 3000",
 298                 },
 299             },
 300         },
 301     }
 302
 303     # Simple lookup of remote peer ip by routers in session (local --> remote).
 304     #
 305     # Structure:
 306     # peer_to_ip = {
 307     #     local_rtr: {
 308     #         peer_rtr: peer_ip
 309     #     }
 310     # }
 311     peer_to_ip = {
 312         "r1": {"r2": "203.0.113.1", "r5": "203.0.113.3"},
 313         "r2": {"r1": "203.0.113.0", "r3": "203.0.113.4", "r4": "203.0.113.8"},
 314         "r3": {"r2": "203.0.113.5", "r5": "203.0.113.7"},
 315         "r4": {"r2": "203.0.113.9", "r5": "203.0.113.11"},
 316         "r5": {"r1": "203.0.113.2", "r3": "203.0.113.6", "r4": "203.0.113.10"},
 317     }
 318
 319     def __bgp_up():
 320         """Return True if all configured peers are Established."""
 321         for router in tx_routers:
 322             output = json.loads(
 323                 tgen.gears[router].vtysh_cmd("show ip bgp summary json")
 324             )
 325             numPeers = output["ipv4Unicast"]["totalPeers"]
 326             numConverged = 0
 327             for peer_data in output["ipv4Unicast"]["peers"].values():
 328                 if peer_data["state"] == "Established":
 329                     numConverged += 1
 330             if numConverged == numPeers:
 331                 return True
 332         return False
 333
 334     def __bgp_converged():
 335         """Return True if all prefixes have been received from tx_routers."""
 336         for router in rx_routers:
 337             output = json.loads(
 338                 tgen.gears[router].vtysh_cmd("show ip bgp summary json")
 339             )
 340             numPeers = output["ipv4Unicast"]["totalPeers"]
 341             numConverged = 0
 342             for peer in tx_routers:
 343                 peer_ip = peer_to_ip[router][peer]
 344                 numPrefixes = output["ipv4Unicast"]["peers"][peer_ip]["pfxRcd"]
 345                 if numPrefixes == len(prefixes):
 346                     numConverged += 1
 347             if numConverged == numPeers:
 348                 return True
 349         return False
 350
 351     def _routers_up(tx_rtrs, rx_rtrs):
 352         """Ensure all BGP sessions are up and all routes are installed."""
 353         # all sessions go through tx_routers, so ensure all their peers are up
 354         test_func = partial(__bgp_up)
 355         _, result = topotest.run_and_expect(test_func, True, count=60, wait=0.5)
 356         assert result == True, "Not all peers in Established state!"
 357
 358         # ensure correct number of routes are installed
 359         test_func = partial(__bgp_converged)
 360         _, result = topotest.run_and_expect(test_func, True, count=60, wait=0.5)
 361         assert result == True, "Not all routes installed in time!"
 362
 363     def _change_remove_type(new_type, op):
 364         """Update config with next remove-private-AS config variant."""
 365         no = "no" if op == "del" else ""
 366         for tr in tx_routers:
 367             for rr in rx_routers:
 368                 p_ip = peer_to_ip[tr][rr]
 369                 tgen.gears[tr].vtysh_multicmd(
 370                     f"""
 371                     configure terminal
 372                     router bgp
 373                     address-family ipv4 unicast
 374                     {no} neighbor {p_ip} {new_type}
 375                     """
 376                 )
 377
 378     def _validate_paths(remove_type):
 379         """Compare actual AS-Path against expected AS-Path."""
 380         for rtr in rx_routers:
 381             for peer in tx_routers:
 382                 p_ip = peer_to_ip[rtr][peer]
 383                 adj_rib_in = json.loads(
 384                     tgen.gears[rtr].vtysh_cmd(
 385                         f"show ip bgp neighbor {p_ip} received-routes json"
 386                     )
 387                 )
 388                 for pfx in prefixes:
 389                     good_path = expected_paths[rtr][remove_type][peer][pfx]
 390                     real_path = adj_rib_in["receivedRoutes"][pfx]["path"]
 391                     return real_path == good_path
 392
 393     #######################
 394     # Begin Test
 395     #######################
 396
 397     # make sure all peers come up and exchange routes
 398     _routers_up(tx_routers, rx_routers)
 399
 400     # test each variation of remove-private-AS
 401     for rmv_type in remove_types:
 402         _change_remove_type(rmv_type, "add")
 403
 404         test_func = partial(_validate_paths, rmv_type)
 405         _, result = topotest.run_and_expect(test_func, True, count=60, wait=0.5)
 406         assert result == True, "Not all routes have correct AS-Path values!"
 407
 408         # each variation sets a separate peer flag in bgpd. we need to clear
 409         # the old flag after each iteration so we only test the flags we expect.
 410         _change_remove_type(rmv_type, "del")
 411
 412     return True
 413
 414
 415 if __name__ == "__main__":
 416     args = ["-s"] + sys.argv[1:]
 417     sys.exit(pytest.main(args))