tests: Check if addpath capability is exchanged dynamically

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

tests/topotests/bgp_dynamic_capability/r1/frr.conf

@@ -13,3 +13,7 @@ router bgp 65001
  neighbor 192.168.1.2 timers connect 1
  neighbor 192.168.1.2 capability dynamic
  !
+ address-family ipv4 unicast
+  neighbor 192.168.1.2 addpath-tx-all-paths
+ exit-address-family
+!

tests/topotests/bgp_dynamic_capability/test_bgp_dynamic_capability_addpath.py

@@ -0,0 +1,170 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+# Copyright (c) 2023 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if Addpath capability is adjusted 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 _, (rname, router) in enumerate(router_list.items(), 1):
+        router.load_frr_config(os.path.join(CWD, "{}/frr.conf".format(rname)))
+
+    tgen.start_router()
+
+
+def teardown_module(mod):
+    tgen = get_topogen()
+    tgen.stop_topology()
+
+
+def test_bgp_dynamic_capability_role():
+    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",
+                    "addPath": {
+                        "ipv4Unicast": {
+                            "txAdvertised": True,
+                            "rxAdvertisedAndReceived": True,
+                        }
+                    },
+                },
+            }
+        }
+        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("Enable Addpath capability and check if it's exchanged dynamically")
+
+    # Clear message stats to check if we receive a notification or not after we
+    # change the settings fo LLGR.
+    r1.vtysh_cmd("clear bgp 192.168.1.2 message-stats")
+    r2.vtysh_cmd(
+        """
+    configure terminal
+    router bgp
+     address-family ipv4 unicast
+      neighbor 192.168.1.1 addpath-tx-all-paths
+    """
+    )
+
+    def _bgp_check_if_addpath_rx_tx_and_session_not_reset():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "addPath": {
+                        "ipv4Unicast": {
+                            "txAdvertisedAndReceived": True,
+                            "rxAdvertisedAndReceived": True,
+                        }
+                    },
+                },
+                "messageStats": {
+                    "notificationsRecv": 0,
+                    "capabilityRecv": 1,
+                },
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_check_if_addpath_rx_tx_and_session_not_reset,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Session was reset after enabling Addpath capability"
+
+    step("Disable Addpath capability RX and check if it's exchanged dynamically")
+
+    # Clear message stats to check if we receive a notification or not after we
+    # change the settings fo LLGR.
+    r1.vtysh_cmd("clear bgp 192.168.1.2 message-stats")
+    r2.vtysh_cmd(
+        """
+    configure terminal
+    router bgp
+     address-family ipv4 unicast
+      neighbor 192.168.1.1 disable-addpath-rx
+    """
+    )
+
+    def _bgp_check_if_addpath_tx_and_session_not_reset():
+        output = json.loads(r1.vtysh_cmd("show bgp neighbor json"))
+        expected = {
+            "192.168.1.2": {
+                "bgpState": "Established",
+                "neighborCapabilities": {
+                    "dynamic": "advertisedAndReceived",
+                    "addPath": {
+                        "ipv4Unicast": {
+                            "txAdvertisedAndReceived": True,
+                            "rxAdvertised": True,
+                        }
+                    },
+                },
+                "messageStats": {
+                    "notificationsRecv": 0,
+                    "capabilityRecv": 1,
+                },
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    test_func = functools.partial(
+        _bgp_check_if_addpath_tx_and_session_not_reset,
+    )
+    _, result = topotest.run_and_expect(test_func, None, count=30, wait=1)
+    assert result is None, "Session was reset after disabling Addpath RX flags"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))