Merge pull request #1145 from hedrok/T8273-fix-ospfv3-no-bdr

T8273: FRR ospfv3: fix LSA when no new BDR elected + remove already merged patch

2 files changed, 62 insertions, 83 deletions

diff --git a/scripts/package-build/frr/patches/frr/0018-zebra-Ensure-FRR-does-not-see-duplicate-local-routes.patch b/scripts/package-build/frr/patches/frr/0018-zebra-Ensure-FRR-does-not-see-duplicate-local-routes.patch
deleted file mode 100644
index f6d033ae..00000000
--- a/scripts/package-build/frr/patches/frr/0018-zebra-Ensure-FRR-does-not-see-duplicate-local-routes.patch
+++ /dev/null
@@ -1,83 +0,0 @@
-From bf1312b8e9f65b7e4046760105dce9bace038fad Mon Sep 17 00:00:00 2001
-From: Donald Sharp <sharpd@nvidia.com>
-Date: Thu, 12 Feb 2026 12:06:33 -0500
-Subject: [PATCH] zebra: Ensure FRR does not see duplicate local routes on
- interface changes
-
-Currently when a interface is seeing multiple link up events in a row,
-we are seeing multiple local routes in the rib:
-
-r9# show ip route vrf all nexthop-group
-% 2026/02/08 23:18:00.371
-
-Codes: K - kernel route, C - connected, L - local, S - static,
-       R - RIP, O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
-       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
-       F - PBR, f - OpenFabric, t - Table-Direct,
-       > - selected route, * - FIB route, q - queued, r - rejected, b - backup
-       t - trapped, o - offload failure
-
-IPv4 unicast VRF default:
-C>* 11.1.5.0/30 (7) is directly connected, r9-eth0, weight 1, 00:01:52
-L>* 11.1.5.2/32 (7) is directly connected, r9-eth0, weight 1, 00:01:52
-B>* 50.1.1.7/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
-B>* 50.1.1.8/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
-L * 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-C * 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-L>* 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-B>* 50.1.1.10/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:50
-L * 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-C * 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-L>* 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-B   198.10.1.1/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:46
-
-Additionally FRR has made an improper choice about what route should also
-be properly selected, because of this decision.  The problem stems from
-rib_compare_routes in zebra_rib.c already handling the multiple same
-connected routes being passed for processing but not for local routes
-to be considered the same.  Modify the code to make local routes behave
-the same here.  This is the new result:
-
-r9# show ip route vrf all nexthop-group
-% 2026/02/08 23:18:00.371
-
-Codes: K - kernel route, C - connected, L - local, S - static,
-       R - RIP, O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
-       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
-       F - PBR, f - OpenFabric, t - Table-Direct,
-       > - selected route, * - FIB route, q - queued, r - rejected, b - backup
-       t - trapped, o - offload failure
-
-IPv4 unicast VRF default:
-C>* 11.1.5.0/30 (7) is directly connected, r9-eth0, weight 1, 00:01:52
-L>* 11.1.5.2/32 (7) is directly connected, r9-eth0, weight 1, 00:01:52
-B>* 50.1.1.7/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
-B>* 50.1.1.8/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:51
-C>* 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-L>* 50.1.1.9/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-B>* 50.1.1.10/32 [20/0] (10) via 11.1.5.1, r9-eth0, weight 1, 00:01:50
-C>* 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-L>* 198.10.1.1/32 (17) is directly connected, r9-eth1, weight 1, 00:01:46
-
-Fixes: #20337
-Signed-off-by: Donald Sharp <sharpd@nvidia.com>
----
- zebra/zebra_rib.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
-index dd18262554..f27c50e6fb 100644
---- a/zebra/zebra_rib.c
-+++ b/zebra/zebra_rib.c
-@@ -1647,7 +1647,7 @@ static bool rib_compare_routes(const struct route_entry *re1, const struct route
- 	 * v6 link-locals, and we also support multiple addresses in the same
- 	 * subnet on a single interface.
- 	 */
--	if (re1->type == ZEBRA_ROUTE_CONNECT &&
-+	if ((re1->type == ZEBRA_ROUTE_CONNECT || re1->type == ZEBRA_ROUTE_LOCAL) &&
- 	    (re1->nhe->nhg.nexthop->ifindex == re2->nhe->nhg.nexthop->ifindex))
- 		return true;
- 
--- 
-2.39.5
-
diff --git a/scripts/package-build/frr/patches/frr/0019-ospf6d-Fix-router-LSA-when-no-new-BDR-elected.patch b/scripts/package-build/frr/patches/frr/0019-ospf6d-Fix-router-LSA-when-no-new-BDR-elected.patch
new file mode 100644
index 00000000..9fd57a97
--- /dev/null
+++ b/scripts/package-build/frr/patches/frr/0019-ospf6d-Fix-router-LSA-when-no-new-BDR-elected.patch
@@ -0,0 +1,62 @@
+From e439e12198474db79ceedfcb34685d6fdc372355 Mon Sep 17 00:00:00 2001
+From: Kyrylo Yatsenko <hedrok@gmail.com>
+Date: Thu, 26 Feb 2026 14:38:17 +0200
+Subject: [PATCH] ospf6d: Fix router LSA when no new BDR elected
+
+When on broadcast network only two routers are eligible to become
+Designated Routers, one of them becomes DR (R1),
+other one becomes BDR (R2).
+
+If after that R1 goes down, R2 becomes DR and network has no BDR.
+
+In this case on all other routers when R1 went down
+`ospf6_router_lsa_originate` originates router LSA without this network
+description as it has no fully adjacent Designated Router yet (it is not
+elected).
+
+But when R2 is elected as DR, no new router LSA is originated in
+`neighbor_change`: it calls `ospf6_interface_state_change`, but state of
+interface is unchanged, so it just returns -1. And for all other routers
+network doesn't exist.
+
+Fix this by originating router LSA in `neighbor_change` for this
+specific case.
+
+Signed-off-by: Kyrylo Yatsenko <hedrok@gmail.com>
+---
+ ospf6d/ospf6_interface.c | 12 +++++++++---
+ 1 file changed, 9 insertions(+), 3 deletions(-)
+
+diff --git a/ospf6d/ospf6_interface.c b/ospf6d/ospf6_interface.c
+index 101d47dd35..dc56ac56cd 100644
+--- a/ospf6d/ospf6_interface.c
++++ b/ospf6d/ospf6_interface.c
+@@ -919,6 +919,7 @@ void backup_seen(struct event *thread)
+ void neighbor_change(struct event *thread)
+ {
+ 	struct ospf6_interface *oi;
++	int ret;
+ 
+ 	oi = (struct ospf6_interface *)EVENT_ARG(thread);
+ 	assert(oi && oi->interface);
+@@ -927,9 +928,14 @@ void neighbor_change(struct event *thread)
+ 		zlog_debug("Interface Event %s: [NeighborChange]",
+ 			   oi->interface->name);
+ 
+-	if (oi->state == OSPF6_INTERFACE_DROTHER ||
+-	    oi->state == OSPF6_INTERFACE_BDR || oi->state == OSPF6_INTERFACE_DR)
+-		ospf6_interface_state_change(dr_election(oi), oi);
++	if (oi->state == OSPF6_INTERFACE_DROTHER || oi->state == OSPF6_INTERFACE_BDR ||
++	    oi->state == OSPF6_INTERFACE_DR) {
++		ret = ospf6_interface_state_change(dr_election(oi), oi);
++
++		/* In this case router LSA is not originated elsewhere */
++		if (oi->type == OSPF_IFTYPE_BROADCAST && ret == -1 && oi->bdrouter == htonl(0))
++			OSPF6_ROUTER_LSA_SCHEDULE(oi->area);
++	}
+ }
+ 
+ void interface_down(struct event *thread)
+-- 
+2.51.2
+