tests/topotests/bgp_ebgp_common_subnet_nexthop_unchanged/test_bgp-ebgp-common-subnet-nexthop-unchanged.py

   1 #!/usr/bin/env python
   2
   3 # Copyright (c) 2021 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 """
  22 https://tools.ietf.org/html/rfc4271
  23
  24 Check if NEXT_HOP attribute is not changed if peer X shares a
  25 common subnet with this address.
  26
  27 - Otherwise, if the route being announced was learned from an
  28   external peer, the speaker can use an IP address of any
  29   adjacent router (known from the received NEXT_HOP attribute)
  30   that the speaker itself uses for local route calculation in
  31   the NEXT_HOP attribute, provided that peer X shares a common
  32   subnet with this address.  This is a second form of "third
  33   party" NEXT_HOP attribute.
  34 """
  35
  36 import os
  37 import sys
  38 import json
  39 import pytest
  40 import functools
  41
  42 pytestmark = [pytest.mark.bgpd]
  43
  44 CWD = os.path.dirname(os.path.realpath(__file__))
  45 sys.path.append(os.path.join(CWD, "../"))
  46
  47 # pylint: disable=C0413
  48 from lib import topotest
  49 from lib.topogen import Topogen, TopoRouter, get_topogen
  50
  51 pytestmark = [pytest.mark.bgpd]
  52
  53
  54 def build_topo(tgen):
  55     for routern in range(1, 4):
  56         tgen.add_router("r{}".format(routern))
  57
  58     switch = tgen.add_switch("s1")
  59     switch.add_link(tgen.gears["r1"])
  60     switch.add_link(tgen.gears["r2"])
  61     switch.add_link(tgen.gears["r3"])
  62
  63
  64 def setup_module(mod):
  65     tgen = Topogen(build_topo, mod.__name__)
  66     tgen.start_topology()
  67
  68     router_list = tgen.routers()
  69
  70     for i, (rname, router) in enumerate(router_list.items(), 1):
  71         router.load_config(
  72             TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
  73         )
  74         router.load_config(
  75             TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
  76         )
  77
  78     tgen.start_router()
  79
  80
  81 def teardown_module(mod):
  82     tgen = get_topogen()
  83     tgen.stop_topology()
  84
  85
  86 def test_bgp_ebgp_common_subnet_nh_unchanged():
  87     tgen = get_topogen()
  88
  89     if tgen.routers_have_failure():
  90         pytest.skip(tgen.errors)
  91
  92     r2 = tgen.gears["r2"]
  93     r3 = tgen.gears["r3"]
  94
  95     def _bgp_converge(router):
  96         output = json.loads(router.vtysh_cmd("show ip bgp summary json"))
  97         expected = {
  98             "ipv4Unicast": {
  99                 "peers": {
 100                     "192.168.1.1": {"state": "Established"},
 101                     "192.168.1.103": {"state": "Established"},
 102                 }
 103             }
 104         }
 105         return topotest.json_cmp(output, expected)
 106
 107     test_func = functools.partial(_bgp_converge, r3)
 108     success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 109
 110     assert result is None, 'Failed bgp convergence in "{}"'.format(r3)
 111
 112     def _bgp_nh_unchanged(router):
 113         output = json.loads(router.vtysh_cmd("show ip bgp 172.16.1.1/32 json"))
 114         expected = {"paths": [{"nexthops": [{"ip": "192.168.1.1"}]}]}
 115         return topotest.json_cmp(output, expected)
 116
 117     test_func = functools.partial(_bgp_nh_unchanged, r2)
 118     success, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
 119
 120     assert result is None, 'Wrong next-hop in "{}"'.format(r2)
 121
 122
 123 if __name__ == "__main__":
 124     args = ["-s"] + sys.argv[1:]
 125     sys.exit(pytest.main(args))