tests: Check if GR settings can be changed via BGP dynamic capabilities

restart-time and/or notification support.

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

tests/topotests/bgp_dynamic_capability/r1/bgpd.conf

@@ -3,6 +3,7 @@
 !
 router bgp 65001
  no bgp ebgp-requires-policy
+ bgp graceful-restart
  neighbor 192.168.1.2 remote-as external
  neighbor 192.168.1.2 timers 1 3
  neighbor 192.168.1.2 timers connect 1

tests/topotests/bgp_dynamic_capability/r2/bgpd.conf

@@ -2,6 +2,7 @@
 !debug bgp neighbor
 !
 router bgp 65002
+ bgp graceful-restart
  no bgp ebgp-requires-policy
  neighbor 192.168.1.1 remote-as external
  neighbor 192.168.1.1 timers 1 3

tests/topotests/bgp_dynamic_capability/test_bgp_dynamic_capability_graceful_restart.py

@@ -0,0 +1,175 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2023 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if BGP graceful restart capability's restart time and notification
+flag are exchanged dynamically.
+"""
+
+import os
+import re
+import sys
+import json
+import pytest
+import functools
+
+pytestmark = pytest.mark.bgpd
+
+CWD = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(CWD, "../"))
+
+# pylint: disable=C0413
+from lib import topotest
+from lib.topogen import Topogen, TopoRouter, get_topogen
+from lib.common_config import step
+
+pytestmark = [pytest.mark.bgpd]
+
+
+def setup_module(mod):
+    topodef = {"s1": ("r1", "r2")}
+    tgen = Topogen(topodef, mod.__name__)
+    tgen.start_topology()
+
+    router_list = tgen.routers()
+
+    for i, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_config(
+            TopoRouter.RD_ZEBRA, os.path.join(CWD, "{}/zebra.conf".format(rname))
+        )
+        router.load_config(
+            TopoRouter.RD_BGP, os.path.join(CWD, "{}/bgpd.conf".format(rname))
+        )
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_dynamic_capability_graceful_restart():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+    r2 = tgen.gears["r2"]
+
+    def _bgp_converge():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "gracefulRestart": "advertisedAndReceived",
+                },
+                "gracefulRestartInfo": {
+                    "nBit": True,
+                    "timers": {
+                        "receivedRestartTimer": 120,
+                    },
+                },
+                "connectionsEstablished": 1,
+                "connectionsDropped": 0,
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_converge,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Can't converge"
+
+    step("Change Graceful-Restart restart-time, and check if it's changed dynamically")
+
+    r2.vtysh_cmd(
+        """
+    configure terminal
+    router bgp
+     bgp graceful-restart restart-time 123
+    """
+    )
+
+    def _bgp_check_if_session_not_reset_after_changing_restart_time():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "gracefulRestart": "advertisedAndReceived",
+                },
+                "gracefulRestartInfo": {
+                    "nBit": True,
+                    "timers": {
+                        "receivedRestartTimer": 123,
+                    },
+                },
+                "connectionsEstablished": 1,
+                "connectionsDropped": 0,
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_check_if_session_not_reset_after_changing_restart_time,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert (
+        result is None
+    ), "Session was reset after changing Graceful-Restart restart-time"
+
+    step(
+        "Disable Graceful-Restart notification support, and check if it's changed dynamically"
+    )
+
+    r2.vtysh_cmd(
+        """
+    configure terminal
+    router bgp
+     no bgp graceful-restart notification
+    """
+    )
+
+    def _bgp_check_if_session_not_reset_after_changing_notification():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "gracefulRestart": "advertisedAndReceived",
+                },
+                "gracefulRestartInfo": {
+                    "nBit": False,
+                    "timers": {
+                        "receivedRestartTimer": 123,
+                    },
+                },
+                "connectionsEstablished": 1,
+                "connectionsDropped": 0,
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_check_if_session_not_reset_after_changing_notification,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert (
+        result is None
+    ), "Session was reset after changing Graceful-Restart notification support"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))