tests/topotests/bgp_tcp_mss/test_bgp_tcp_mss.py

   1 #!/usr/bin/env python
   2 # SPDX-License-Identifier: ISC
   3
   4 #
   5 # bgp_tcp_mss.py
   6 # Part of NetDEF Topology Tests
   7 #
   8 # Copyright (c) 2021 by
   9 # Abhinay Ramesh <rabhinay@vmware.com>
  10 #
  11
  12 """
  13 bgp_tcp_mss.py:
  14
  15 Test if works the following commands:
  16 router bgp 65000
  17   neighbor 192.168.255.2 tcp-mss 500
  18
  19 Need to verify if the tcp-mss value is reflected in the TCP session.
  20 """
  21
  22 import os
  23 import sys
  24 import json
  25 import pytest
  26 import functools
  27
  28 # add after imports, before defining classes or functions:
  29 pytestmark = [pytest.mark.bgpd]
  30
  31 CWD = os.path.dirname(os.path.realpath(__file__))
  32 sys.path.append(os.path.join(CWD, "../"))
  33
  34 # pylint: disable=C0413
  35 from lib import topotest
  36 from lib.topogen import Topogen, TopoRouter, get_topogen
  37 from lib.topolog import logger
  38
  39 pytestmark = [pytest.mark.bgpd]
  40
  41
  42 def build_topo(tgen):
  43     for routern in range(1, 3):
  44         tgen.add_router("r{}".format(routern))
  45
  46     switch = tgen.add_switch("s1")
  47     switch.add_link(tgen.gears["r1"])
  48     switch.add_link(tgen.gears["r2"])
  49
  50
  51 def setup_module(mod):
  52     tgen = Topogen(build_topo, mod.__name__)
  53     tgen.start_topology()
  54
  55     router_list = tgen.routers()
  56
  57     for i, (rname, router) in enumerate(router_list.items(), 1):
  58         router.load_config(
  59             TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
  60         )
  61         router.load_config(
  62             TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
  63         )
  64
  65     tgen.start_router()
  66
  67
  68 def teardown_module(mod):
  69     tgen = get_topogen()
  70     tgen.stop_topology()
  71
  72
  73 def test_bgp_tcp_mss():
  74     tgen = get_topogen()
  75
  76     if tgen.routers_have_failure():
  77         pytest.skip(tgen.errors)
  78
  79     router1 = tgen.gears["r1"]
  80     router2 = tgen.gears["r2"]
  81
  82     def _bgp_converge(router):
  83         output = json.loads(router.vtysh_cmd("show ip bgp neighbor 192.168.255.2 json"))
  84         expected = {
  85             "192.168.255.2": {
  86                 "bgpState": "Established",
  87                 "addressFamilyInfo": {"ipv4Unicast": {"acceptedPrefixCounter": 0}},
  88             }
  89         }
  90         return topotest.json_cmp(output, expected)
  91
  92     def _bgp_conf_tcp_mss(router, as_num, neigh):
  93         router.vtysh_cmd(
  94             """configure terminal
  95                router bgp {0}
  96                  neighbor {1} tcp-mss 500""".format(
  97                 as_num, neigh
  98             )
  99         )
 100
 101     def _bgp_clear_session(router):
 102         router.vtysh_cmd("clear bgp *")
 103
 104     def _bgp_check_neighbor_tcp_mss(router, neigh):
 105         output = json.loads(router.vtysh_cmd("show bgp neighbor {} json".format(neigh)))
 106         expected = {
 107             "{}".format(neigh): {"bgpTcpMssConfigured": 500, "bgpTcpMssSynced": 488}
 108         }
 109         return topotest.json_cmp(output, expected)
 110
 111     logger.info("Check if neighbor sessions are up in {}".format(router1.name))
 112     test_func = functools.partial(_bgp_converge, router1)
 113     success, result = topotest.run_and_expect(test_func, None, count=15, wait=0.5)
 114     assert result is None, 'Failed to see BGP convergence in "{}"'.format(router1.name)
 115
 116     logger.info("BGP neighbor session is up in {}".format(router1.name))
 117
 118     logger.info(
 119         "Configure tcp-mss 500 on {} and reset the session".format(router1.name)
 120     )
 121     _bgp_conf_tcp_mss(router1, "65000", "192.168.255.2")
 122     _bgp_clear_session(router1)
 123
 124     logger.info(
 125         "Configure tcp-mss 500 on {} and reset the session".format(router2.name)
 126     )
 127     _bgp_conf_tcp_mss(router2, "65001", "192.168.255.1")
 128     _bgp_clear_session(router2)
 129
 130     logger.info(
 131         "Check if neighbor session is up after reset in {}".format(router1.name)
 132     )
 133     test_func = functools.partial(_bgp_converge, router1)
 134     success, result = topotest.run_and_expect(test_func, None, count=15, wait=0.5)
 135     assert result is None, 'Failed to see BGP convergence after reset in "{}"'.format(
 136         router1.name
 137     )
 138
 139     logger.info(
 140         "Verify if TCP MSS value is synced with neighbor in {}".format(router1.name)
 141     )
 142     test_func = functools.partial(_bgp_check_neighbor_tcp_mss, router1, "192.168.255.2")
 143     success, result = topotest.run_and_expect(test_func, None, count=10, wait=0.5)
 144     assert (
 145         result is None
 146     ), 'Failed to sync TCP MSS value over BGP session in "{}"'.format(router1.name)
 147     logger.info("TCP MSS value is synced with neighbor in {}".format(router1.name))
 148
 149     logger.info(
 150         "Verify if TCP MSS value is synced with neighbor in {}".format(router2.name)
 151     )
 152     test_func = functools.partial(_bgp_check_neighbor_tcp_mss, router2, "192.168.255.1")
 153     success, result = topotest.run_and_expect(test_func, None, count=10, wait=0.5)
 154     assert (
 155         result is None
 156     ), 'Failed to sync TCP MSS value over BGP session in "{}"'.format(router2.name)
 157     logger.info("TCP MSS value is synced with neighbor in {}".format(router2.name))
 158
 159
 160 if __name__ == "__main__":
 161     args = ["-s"] + sys.argv[1:]
 162     sys.exit(pytest.main(args))