bgpd: Allow BGP to process certain routes early

There is a need to be able to process certain bgp
routes earlier than others.  Especially when there
is major trauma going on in the network.  Start
the ability for this to happen.

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

diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 3c0f0c8b53b1d43de6d9c7bff834a33fcc3ef809..4cf9a6b5f9928650f2ed8bf3fa74d5b33b84a167 100644 (file)
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -4011,8 +4011,9 @@ static struct bgp_process_queue *bgp_processq_alloc(struct bgp *bgp)
        return pqnode;
 }
 
-void bgp_process(struct bgp *bgp, struct bgp_dest *dest,
-                struct bgp_path_info *pi, afi_t afi, safi_t safi)
+static void bgp_process_internal(struct bgp *bgp, struct bgp_dest *dest,
+                                struct bgp_path_info *pi, afi_t afi,
+                                safi_t safi, bool early_process)
 {
 #define ARBITRARY_PROCESS_QLEN         10000
        struct work_queue *wq = bgp->process_queue;
@@ -4075,9 +4076,9 @@ void bgp_process(struct bgp *bgp, struct bgp_dest *dest,
                struct work_queue_item *item = work_queue_last_item(wq);
                pqnode = item->data;
 
-               if (CHECK_FLAG(pqnode->flags, BGP_PROCESS_QUEUE_EOIU_MARKER)
-                   || pqnode->bgp != bgp
-                   || pqnode->queued >= ARBITRARY_PROCESS_QLEN)
+               if (CHECK_FLAG(pqnode->flags, BGP_PROCESS_QUEUE_EOIU_MARKER) ||
+                   pqnode->bgp != bgp ||
+                   (pqnode->queued >= ARBITRARY_PROCESS_QLEN && !early_process))
                        pqnode = bgp_processq_alloc(bgp);
                else
                        pqnode_reuse = 1;
@@ -4091,7 +4092,10 @@ void bgp_process(struct bgp *bgp, struct bgp_dest *dest,
 
        /* can't be enqueued twice */
        assert(STAILQ_NEXT(dest, pq) == NULL);
-       STAILQ_INSERT_TAIL(&pqnode->pqueue, dest, pq);
+       if (early_process)
+               STAILQ_INSERT_HEAD(&pqnode->pqueue, dest, pq);
+       else
+               STAILQ_INSERT_TAIL(&pqnode->pqueue, dest, pq);
        pqnode->queued++;
 
        if (!pqnode_reuse)
@@ -4100,6 +4104,18 @@ void bgp_process(struct bgp *bgp, struct bgp_dest *dest,
        return;
 }
 
+void bgp_process(struct bgp *bgp, struct bgp_dest *dest,
+                struct bgp_path_info *pi, afi_t afi, safi_t safi)
+{
+       bgp_process_internal(bgp, dest, pi, afi, safi, false);
+}
+
+void bgp_process_early(struct bgp *bgp, struct bgp_dest *dest,
+                      struct bgp_path_info *pi, afi_t afi, safi_t safi)
+{
+       bgp_process_internal(bgp, dest, pi, afi, safi, true);
+}
+
 void bgp_add_eoiu_mark(struct bgp *bgp)
 {
        struct bgp_process_queue *pqnode;

diff --git a/bgpd/bgp_route.h b/bgpd/bgp_route.h
index bc3ca4b2f8960b37d00830f24a139a159aea0b10..b6df2411812b1a9335ae45482e2b1331d5f843e5 100644 (file)
--- a/bgpd/bgp_route.h
+++ b/bgpd/bgp_route.h
@@ -804,10 +804,20 @@ extern void bgp_withdraw(struct peer *peer, const struct prefix *p,
                         int sub_type, struct prefix_rd *prd,
                         mpls_label_t *label, uint8_t num_labels);
 
-/* for bgp_nexthop and bgp_damp */
+/*
+ * Add a route to be processed for bgp bestpath through the bgp
+ * workqueue.  This route is added to the end of all other routes
+ * queued for processing
+ *
+ * bgp_process_early adds the route for processing at the beginning
+ * of the current queue for processing.
+ */
 extern void bgp_process(struct bgp *bgp, struct bgp_dest *dest,
                        struct bgp_path_info *pi, afi_t afi, safi_t safi);
 
+extern void bgp_process_early(struct bgp *bgp, struct bgp_dest *dest,
+                             struct bgp_path_info *pi, afi_t afi, safi_t safi);
+
 /*
  * Add an end-of-initial-update marker to the process queue. This is just a
  * queue element with NULL bgp node.