zebra: Install directly connected route after interface flap

Issue:
After vlan flap, zebra was not marking the selected/best route as installed.

As a result, when a static route was configured with nexthop as directly
connected interface's(vlan) IP, the static route was not being installed
in the kernel since its nexthop was unresolved. The nexthop was marked
unresolved because zebra failed to mark the best route as installed after
interface flap.

This was happening because, in dplane_route_update_internal() if the old and
new context type, and nexthop group id are the same, then zebra doesn't send
down a route replace request to kernel. But, the installed (ROUTE_ENTRY_INSTALLED)
flag is set when zebra receives a response from kernel. Since the
request to kernel was being skipped for the route entry, installed flag
was not being set

Fix:
In dplane_route_update_internal() if the old and new context type, and
nexthop group id are the same, then before returning, installed flag will
be set on the route-entry if it's not set already.

Signed-off-by: Pooja Jagadeesh Doijode <pdoijode@nvidia.com>
(cherry picked from commit e25a0b138a196c7daf389989ebffbd09d345cd53)

diff --git a/zebra/zebra_dplane.c b/zebra/zebra_dplane.c
index 612b920e738b286fb0ee48ec5160f433ff92b745..2b8f62993653512640236099afe5fcd8acd8d9d1 100644 (file)
--- a/zebra/zebra_dplane.c
+++ b/zebra/zebra_dplane.c
@@ -3479,6 +3479,11 @@ dplane_route_update_internal(struct route_node *rn,
                                                 NEXTHOP_FLAG_FIB);
                        }
 
+                       if ((op == DPLANE_OP_ROUTE_UPDATE) && old_re && re &&
+                           (old_re != re) &&
+                           !CHECK_FLAG(re->status, ROUTE_ENTRY_INSTALLED))
+                               SET_FLAG(re->status, ROUTE_ENTRY_INSTALLED);
+
                        dplane_ctx_free(&ctx);
                        return ZEBRA_DPLANE_REQUEST_SUCCESS;
                }