zebra: Make connected routes their own entry on the meta_q

During quick ifdown / ifup events from the linux kernel there
exists a situation where a prefix that has both a kernel route
and a static route can queued up on the meta-q.  If the static
route happens to point at a connected route for nexthop resolution
and we receive a series of quick up/down events *after* the
static route and kernel route are queued up for rib reprocessing.
Since the static route and kernel route are queued on meta-q 1
and the connected route is also on meta-q 1 there exists a situation
where the connected route will be resolved after the static route
fails to resolve, leaving the static route in a unresolved state.

Add a new queue level and put connected routes on their own level,
since they are the fundamental building blocks of pretty much
all the other routes.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/zebra/rib.h b/zebra/rib.h
index be680a112f..38f8029791 100644
--- a/zebra/rib.h
+++ b/zebra/rib.h
@@ -165,13 +165,15 @@ struct route_entry {
 
 /* meta-queue structure:
  * sub-queue 0: nexthop group objects
- * sub-queue 1: connected, kernel
- * sub-queue 2: static
- * sub-queue 3: RIP, RIPng, OSPF, OSPF6, IS-IS, EIGRP, NHRP
- * sub-queue 4: iBGP, eBGP
- * sub-queue 5: any other origin (if any)
+ * sub-queue 1: connected
+ * sub-queue 2: kernel
+ * sub-queue 3: static
+ * sub-queue 4: RIP, RIPng, OSPF, OSPF6, IS-IS, EIGRP, NHRP
+ * sub-queue 5: iBGP, eBGP
+ * sub-queue 6: any other origin (if any) typically those that
+ *              don't generate routes
  */
-#define MQ_SIZE 6
+#define MQ_SIZE 7
 struct meta_queue {
 	struct list *subq[MQ_SIZE];
 	uint32_t size; /* sum of lengths of all subqueues */