Merge pull request #3477 from donaldsharp/multipath_respect

zebra: Allow zebra to only mark up to multipath_num nexthops as ACTIVE

2 files changed, 14 insertions, 15 deletions

diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index cb9ef8e36..8ce963b37 100644
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -1584,7 +1584,7 @@ static int netlink_route_multipath(int cmd, struct zebra_dplane_ctx *ctx)
 	}
 
 	/* Singlepath case. */
-	if (nexthop_num == 1 || multipath_num == 1) {
+	if (nexthop_num == 1) {
 		nexthop_num = 0;
 		for (ALL_NEXTHOPS_PTR(dplane_ctx_get_ng(ctx), nexthop)) {
 			/*
@@ -1676,9 +1676,6 @@ static int netlink_route_multipath(int cmd, struct zebra_dplane_ctx *ctx)
 
 		nexthop_num = 0;
 		for (ALL_NEXTHOPS_PTR(dplane_ctx_get_ng(ctx), nexthop)) {
-			if (nexthop_num >= multipath_num)
-				break;
-
 			if (CHECK_FLAG(nexthop->flags,
 				       NEXTHOP_FLAG_RECURSIVE)) {
 				/* This only works for IPv4 now */
@@ -1876,12 +1873,6 @@ enum zebra_dplane_result kernel_route_update(struct zebra_dplane_ctx *ctx)
 
 			if (CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE)) {
 				SET_FLAG(nexthop->flags, NEXTHOP_FLAG_FIB);
-
-				/* If we're only allowed a single nh, don't
-				 * continue.
-				 */
-				if (multipath_num == 1)
-					break;
 			}
 		}
 	}
@@ -2698,7 +2689,7 @@ int netlink_mpls_multipath(int cmd, zebra_lsp_t *lsp)
 	/* Fill nexthops (paths) based on single-path or multipath. The paths
 	 * chosen depend on the operation.
 	 */
-	if (nexthop_num == 1 || multipath_num == 1) {
+	if (nexthop_num == 1) {
 		routedesc = "single-path";
 		_netlink_mpls_debug(cmd, lsp->ile.in_label, routedesc);
 
@@ -2745,9 +2736,6 @@ int netlink_mpls_multipath(int cmd, zebra_lsp_t *lsp)
 			if (!nexthop)
 				continue;
 
-			if (nexthop_num >= multipath_num)
-				break;
-
 			if ((cmd == RTM_NEWROUTE
 			     && (CHECK_FLAG(nhlfe->flags, NHLFE_FLAG_SELECTED)
 				 && CHECK_FLAG(nexthop->flags,
diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
index c7ad2508f..d628b801a 100644
--- a/zebra/zebra_rib.c
+++ b/zebra/zebra_rib.c
@@ -971,7 +971,18 @@ static int nexthop_active_update(struct route_node *rn, struct route_entry *re,
 		prev_src = nexthop->rmap_src;
 		prev_active = CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
 		prev_index = nexthop->ifindex;
-		if ((new_active = nexthop_active_check(rn, re, nexthop, set)))
+		/*
+		 * We need to respect the multipath_num here
+		 * as that what we should be able to install from
+		 * a multipath perpsective should not be a data plane
+		 * decision point.
+		 */
+		new_active = nexthop_active_check(rn, re, nexthop, set);
+		if (new_active && re->nexthop_active_num >= multipath_num) {
+			UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
+			new_active = 0;
+		}
+		if (new_active)
 			re->nexthop_active_num++;
 		/* Don't allow src setting on IPv6 addr for now */
 		if (prev_active != new_active || prev_index != nexthop->ifindex