tests: Check if Graceful Restart per-neighbor works as expected

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

tests/topotests/bgp_gr_restart_retain_routes/r3/frr.conf

@@ -0,0 +1,19 @@
+no zebra nexthop kernel enable
+!
+interface lo
+ ip address 172.16.255.3/32
+!
+interface r3-eth0
+ ip address 192.168.34.3/24
+!
+router bgp 65003
+ no bgp ebgp-requires-policy
+ bgp graceful-restart preserve-fw-state
+ neighbor 192.168.34.4 remote-as external
+ neighbor 192.168.34.4 timers 1 3
+ neighbor 192.168.34.4 timers connect 1
+ neighbor 192.168.34.4 graceful-restart
+ address-family ipv4
+  redistribute connected
+ exit-address-family
+!

tests/topotests/bgp_gr_restart_retain_routes/r4/frr.conf

@@ -0,0 +1,15 @@
+no zebra nexthop kernel enable
+debug bgp graceful-restart
+debug bgp neighbor
+!
+interface r4-eth0
+ ip address 192.168.34.4/24
+!
+router bgp 65004
+ no bgp ebgp-requires-policy
+ bgp graceful-restart preserve-fw-state
+ neighbor 192.168.34.3 remote-as external
+ neighbor 192.168.34.3 timers 1 3
+ neighbor 192.168.34.3 timers connect 1
+ neighbor 192.168.34.3 graceful-restart
+!

tests/topotests/bgp_gr_restart_retain_routes/test_bgp_gr_per_neighbor_restart_retain_routes.py

@@ -0,0 +1,108 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+#
+# Copyright (c) 2024 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Test if routes are retained during BGP restarts using
+ Graceful Restart per-neighbor.
+"""
+
+import os
+import sys
+import json
+import pytest
+import functools
+
+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, stop_router
+
+pytestmark = [pytest.mark.bgpd]
+
+
+def build_topo(tgen):
+    for routern in range(1, 5):
+        tgen.add_router("r{}".format(routern))
+
+    switch = tgen.add_switch("s1")
+    switch.add_link(tgen.gears["r3"])
+    switch.add_link(tgen.gears["r4"])
+
+
+def setup_module(mod):
+    tgen = Topogen(build_topo, 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_gr_restart_retain_routes():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r4 = tgen.gears["r4"]
+
+    def _bgp_converge():
+        output = json.loads(r4.vtysh_cmd("show bgp ipv4 neighbors 192.168.34.3 json"))
+        expected = {
+            "192.168.34.3": {
+                "bgpState": "Established",
+                "addressFamilyInfo": {"ipv4Unicast": {"acceptedPrefixCounter": 2}},
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    def _bgp_check_bgp_retained_routes():
+        output = json.loads(r4.vtysh_cmd("show bgp ipv4 unicast 172.16.255.3/32 json"))
+        expected = {"paths": [{"stale": True}]}
+        return topotest.json_cmp(output, expected)
+
+    def _bgp_check_kernel_retained_routes():
+        output = json.loads(
+            r4.cmd("ip -j route show 172.16.255.3/32 proto bgp dev r4-eth0")
+        )
+        expected = [{"dst": "172.16.255.3", "gateway": "192.168.34.3", "metric": 20}]
+        return topotest.json_cmp(output, expected)
+
+    step("Initial BGP converge")
+    test_func = functools.partial(_bgp_converge)
+    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "Failed to see BGP convergence on R4"
+
+    step("Restart R3")
+    stop_router(tgen, "r3")
+
+    step("Check if routes (BGP) are retained at R4")
+    test_func = functools.partial(_bgp_check_bgp_retained_routes)
+    _, result = topotest.run_and_expect(test_func, None, count=60, wait=0.5)
+    assert result is None, "Failed to see BGP retained routes on R4"
+
+    step("Check if routes (Kernel) are retained at R4")
+    assert (
+        _bgp_check_kernel_retained_routes() is None
+    ), "Failed to retain BGP routes in kernel on R4"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))

tests/topotests/bgp_gr_restart_retain_routes/test_bgp_gr_restart_retain_routes.py

@@ -42,13 +42,8 @@ def setup_module(mod):
 
     router_list = tgen.routers()
 
-    for i, (rname, router) in enumerate(router_list.items(), 1):
+    for _, (rname, router) in enumerate(router_list.items(), 1):
-        router.load_config(
+        router.load_frr_config(os.path.join(CWD, "{}/frr.conf".format(rname)))
-            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()
 
@@ -83,7 +78,9 @@ def test_bgp_gr_restart_retain_routes():
         return topotest.json_cmp(output, expected)
 
     def _bgp_check_kernel_retained_routes():
-        output = json.loads(r2.cmd("ip -j route show 172.16.255.1/32 proto bgp dev r2-eth0"))
+        output = json.loads(
+            r2.cmd("ip -j route show 172.16.255.1/32 proto bgp dev r2-eth0")
+        )
         expected = [{"dst": "172.16.255.1", "gateway": "192.168.255.1", "metric": 20}]
         return topotest.json_cmp(output, expected)
 
@@ -101,7 +98,9 @@ def test_bgp_gr_restart_retain_routes():
     assert result is None, "Failed to see BGP retained routes on R2"
 
     step("Check if routes (Kernel) are retained at R2")
-    assert _bgp_check_kernel_retained_routes() is None, "Failed to retain BGP routes in kernel on R2"
+    assert (
+        _bgp_check_kernel_retained_routes() is None
+    ), "Failed to retain BGP routes in kernel on R2"
 
 
 if __name__ == "__main__":