Merge pull request #12962 from opensourcerouting/fix/bgpd_ipv6_ll_peering

bgpd: Check if the peer is configured as interface when checking NHT

7 files changed, 109 insertions, 1 deletions

diff --git a/bgpd/bgp_nht.c b/bgpd/bgp_nht.c
index 25b458a8e5..473c95071c 100644
--- a/bgpd/bgp_nht.c
+++ b/bgpd/bgp_nht.c
@@ -324,7 +324,7 @@ int bgp_find_or_add_nexthop(struct bgp *bgp_route, struct bgp *bgp_nexthop,
 		 * Gather the ifindex for if up/down events to be
 		 * tagged into this fun
 		 */
-		if (afi == AFI_IP6 &&
+		if (afi == AFI_IP6 && peer->conf_if &&
 		    IN6_IS_ADDR_LINKLOCAL(&peer->su.sin6.sin6_addr)) {
 			ifindex = peer->su.sin6.sin6_scope_id;
 			if (ifindex == 0) {
diff --git a/tests/topotests/bgp_ipv6_ll_peering/__init__.py b/tests/topotests/bgp_ipv6_ll_peering/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/topotests/bgp_ipv6_ll_peering/__init__.py
diff --git a/tests/topotests/bgp_ipv6_ll_peering/r1/bgpd.conf b/tests/topotests/bgp_ipv6_ll_peering/r1/bgpd.conf
new file mode 100644
index 0000000000..724cbf84ab
--- /dev/null
+++ b/tests/topotests/bgp_ipv6_ll_peering/r1/bgpd.conf
@@ -0,0 +1,6 @@
+router bgp 65001
+ bgp router-id 10.0.0.1
+ no bgp ebgp-requires-policy
+ neighbor fe80:1::2 remote-as external
+ neighbor fe80:1::2 timers 3 10
+ neighbor fe80:1::2 interface r1-eth0
diff --git a/tests/topotests/bgp_ipv6_ll_peering/r1/zebra.conf b/tests/topotests/bgp_ipv6_ll_peering/r1/zebra.conf
new file mode 100644
index 0000000000..4e93d4f4e5
--- /dev/null
+++ b/tests/topotests/bgp_ipv6_ll_peering/r1/zebra.conf
@@ -0,0 +1,4 @@
+!
+interface r1-eth0
+ ipv6 address fe80:1::1/64
+!
diff --git a/tests/topotests/bgp_ipv6_ll_peering/r2/bgpd.conf b/tests/topotests/bgp_ipv6_ll_peering/r2/bgpd.conf
new file mode 100644
index 0000000000..44f79dfc33
--- /dev/null
+++ b/tests/topotests/bgp_ipv6_ll_peering/r2/bgpd.conf
@@ -0,0 +1,6 @@
+router bgp 65002
+ bgp router-id 10.0.0.2
+ no bgp ebgp-requires-policy
+ neighbor fe80:1::1 remote-as external
+ neighbor fe80:1::1 timers 3 10
+ neighbor fe80:1::1 interface r2-eth0
diff --git a/tests/topotests/bgp_ipv6_ll_peering/r2/zebra.conf b/tests/topotests/bgp_ipv6_ll_peering/r2/zebra.conf
new file mode 100644
index 0000000000..1e703cda36
--- /dev/null
+++ b/tests/topotests/bgp_ipv6_ll_peering/r2/zebra.conf
@@ -0,0 +1,4 @@
+!
+interface r2-eth0
+ ipv6 address fe80:1::2/64
+!
diff --git a/tests/topotests/bgp_ipv6_ll_peering/test_bgp_ipv6_ll_peering.py b/tests/topotests/bgp_ipv6_ll_peering/test_bgp_ipv6_ll_peering.py
new file mode 100644
index 0000000000..ea974b5302
--- /dev/null
+++ b/tests/topotests/bgp_ipv6_ll_peering/test_bgp_ipv6_ll_peering.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: ISC
+
+#
+# Copyright (c) 2023 by
+# Donatas Abraitis <donatas@opensourcerouting.org>
+#
+
+"""
+Check if IPv6 Link-Local BGP peering works fine.
+"""
+
+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
+
+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_ipv6_link_local_peering():
+    tgen = get_topogen()
+
+    if tgen.routers_have_failure():
+        pytest.skip(tgen.errors)
+
+    r1 = tgen.gears["r1"]
+
+    def _bgp_converge():
+        output = json.loads(r1.vtysh_cmd("show bgp summary json"))
+        expected = {
+            "ipv4Unicast": {
+                "peers": {
+                    "fe80:1::2": {
+                        "state": "Established",
+                    }
+                }
+            }
+        }
+        return topotest.json_cmp(output, expected)
+
+    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"
+
+
+if __name__ == "__main__":
+    args = ["-s"] + sys.argv[1:]
+    sys.exit(pytest.main(args))