bgpd: Do not send Deconfig/Shutdown message when restarting

We might disable sending unconfig/shutdown notifications when
Graceful-Restart is enabled and negotiated.

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

bgpd/bgpd.c

@@ -2760,6 +2760,21 @@ void peer_notify_unconfig(struct peer *peer)
 				BGP_NOTIFY_CEASE_PEER_UNCONFIG);
 }
 
+static void peer_notify_shutdown(struct peer *peer)
+{
+	if (BGP_PEER_GRACEFUL_RESTART_CAPABLE(peer)) {
+		if (bgp_debug_neighbor_events(peer))
+			zlog_debug(
+				"%pBP configured Graceful-Restart, skipping shutdown notification",
+				peer);
+		return;
+	}
+
+	if (BGP_IS_VALID_STATE_FOR_NOTIF(peer->status))
+		bgp_notify_send(peer, BGP_NOTIFY_CEASE,
+				BGP_NOTIFY_CEASE_ADMIN_SHUTDOWN);
+}
+
 void peer_group_notify_unconfig(struct peer_group *group)
 {
 	struct peer *peer, *other;
@@ -3676,11 +3691,8 @@ int bgp_delete(struct bgp *bgp)
 	}
 
 	/* Inform peers we're going down. */
-	for (ALL_LIST_ELEMENTS(bgp->peer, node, next, peer)) {
-		if (BGP_IS_VALID_STATE_FOR_NOTIF(peer->status))
-			bgp_notify_send(peer, BGP_NOTIFY_CEASE,
-					BGP_NOTIFY_CEASE_ADMIN_SHUTDOWN);
-	}
+	for (ALL_LIST_ELEMENTS(bgp->peer, node, next, peer))
+		peer_notify_shutdown(peer);
 
 	/* Delete static routes (networks). */
 	bgp_static_delete(bgp);
@@ -8251,11 +8263,18 @@ void bgp_terminate(void)
 	/* reverse bgp_master_init */
 	for (ALL_LIST_ELEMENTS(bm->bgp, mnode, mnnode, bgp)) {
 		bgp_close_vrf_socket(bgp);
-		for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer))
-			if (peer_established(peer) || peer->status == OpenSent
-			    || peer->status == OpenConfirm)
+		for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
+			if (BGP_PEER_GRACEFUL_RESTART_CAPABLE(peer)) {
+				if (bgp_debug_neighbor_events(peer))
+					zlog_debug(
+						"%pBP configured Graceful-Restart, skipping unconfig notification",
+						peer);
+				continue;
+			}
+			if (BGP_IS_VALID_STATE_FOR_NOTIF(peer->status))
 				bgp_notify_send(peer, BGP_NOTIFY_CEASE,
 						BGP_NOTIFY_CEASE_PEER_UNCONFIG);
+		}
 	}
 
 	if (bm->listen_sockets)

tests/topotests/bgp_gr_restart_retain_routes/r1/bgpd.conf

@@ -0,0 +1,11 @@
+router bgp 65001
+ no bgp ebgp-requires-policy
+ bgp graceful-restart
+ bgp graceful-restart preserve-fw-state
+ neighbor 192.168.255.2 remote-as external
+ neighbor 192.168.255.2 timers 1 3
+ neighbor 192.168.255.2 timers connect 1
+ address-family ipv4
+  redistribute connected
+ exit-address-family
+!

tests/topotests/bgp_gr_restart_retain_routes/r1/zebra.conf

@@ -0,0 +1,9 @@
+!
+interface lo
+ ip address 172.16.255.1/32
+!
+interface r1-eth0
+ ip address 192.168.255.1/24
+!
+ip forwarding
+!

tests/topotests/bgp_gr_restart_retain_routes/r2/bgpd.conf

@@ -0,0 +1,11 @@
+router bgp 65002
+ no bgp ebgp-requires-policy
+ bgp graceful-restart
+ bgp graceful-restart preserve-fw-state
+ neighbor 192.168.255.1 remote-as external
+ neighbor 192.168.255.1 timers 1 3
+ neighbor 192.168.255.1 timers connect 1
+ address-family ipv4
+  redistribute connected
+ exit-address-family
+!

tests/topotests/bgp_gr_restart_retain_routes/r2/zebra.conf

@@ -0,0 +1,9 @@
+!
+interface lo
+ ip address 172.16.255.2/32
+!
+interface r2-eth0
+ ip address 192.168.255.2/24
+!
+ip forwarding
+!

tests/topotests/bgp_gr_restart_retain_routes/test_bgp_gr_restart_retain_routes.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python
+
+#
+# Copyright (c) 2022 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+# Permission to use, copy, modify, and/or distribute this software
+# for any purpose with or without fee is hereby granted, provided
+# that the above copyright notice and this permission notice appear
+# in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND NETDEF DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
+# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
+# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+# OF THIS SOFTWARE.
+#
+
+"""
+Test if routes are retained during BGP restarts.
+"""
+
+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, 3):
+        tgen.add_router("r{}".format(routern))
+
+    switch = tgen.add_switch("s1")
+    switch.add_link(tgen.gears["r1"])
+    switch.add_link(tgen.gears["r2"])
+
+
+def setup_module(mod):
+    tgen = Topogen(build_topo, 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_gr_restart_retain_routes():
+    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(r2.vtysh_cmd("show bgp ipv4 neighbors 192.168.255.1 json"))
+        expected = {
+            "192.168.255.1": {
+                "bgpState": "Established",
+                "addressFamilyInfo": {"ipv4Unicast": {"acceptedPrefixCounter": 2}},
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    def _bgp_check_retained_routes():
+        output = json.loads(r2.vtysh_cmd("show bgp ipv4 unicast 172.16.255.1/32 json"))
+        expected = {"paths": [{"stale": True}]}
+        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 R2"
+
+    step("Restart R1")
+    stop_router(tgen, "r1")
+
+    step("Check if routes are retained at R2")
+    test_func = functools.partial(_bgp_check_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 R2"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))