Implemented garbage collection of routing tables to delete orphaned network

nodes having no routes attached. Such cleanup must be done from event handler
since most functions manipulating the routing tables expect network entries
won't disappear from under their hands and it's also probably faster when
done asynchronously.

1 files changed, 38 insertions, 8 deletions

diff --git a/nest/rt-table.c b/nest/rt-table.c
index 73b679d5..621a8353 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -14,11 +14,20 @@
 #include "nest/route.h"
 #include "nest/protocol.h"
 #include "lib/resource.h"
+#include "lib/event.h"
 
 rtable master_table;
 static slab *rte_slab;
 
-void
+#define RT_GC_MIN_TIME 5		/* FIXME: Make configurable */
+#define RT_GC_MIN_COUNT 100
+
+static pool *rt_table_pool;
+static event *rt_gc_event;
+static bird_clock_t rt_last_gc;
+static int rt_gc_counter;
+
+static void
 rte_init(struct fib_node *N)
 {
   net *n = (net *) N;
@@ -206,6 +215,8 @@ rte_update(net *net, struct proto *p, rte *new)
 		}
 	      r->next = net->routes;
 	      net->routes = r;
+	      if (!r && rt_gc_counter++ >= RT_GC_MIN_COUNT && rt_last_gc + RT_GC_MIN_TIME <= now)
+		ev_schedule(rt_gc_event);
 	    }
 	}
       if (new)				/* Link in the new non-optimal route */
@@ -280,19 +291,32 @@ rt_dump_all(void)
   rt_dump(&master_table);
 }
 
+static void
+rt_gc(void *unused)
+{
+  DBG("Entered routing table garbage collector after %d seconds and %d deletes\n", (int)(now - rt_last_gc), rt_gc_counter);
+  rt_prune(&master_table);
+  rt_last_gc = now;
+  rt_gc_counter = 0;
+}
+
 void
 rt_init(void)
 {
   rta_init();
+  rt_table_pool = rp_new(&root_pool, "Routing tables");
   rt_setup(&master_table, "master");
-  rte_slab = sl_new(&root_pool, sizeof(rte));
+  rte_slab = sl_new(rt_table_pool, sizeof(rte));
+  rt_last_gc = now;
+  rt_gc_event = ev_new(rt_table_pool);
+  rt_gc_event->hook = rt_gc;
 }
 
 void
 rt_prune(rtable *tab)
 {
   struct fib_iterator fit;
-  int cnt = 0;
+  int rcnt = 0, rdel = 0, ncnt = 0, ndel = 0;
 
   DBG("Pruning route table %s\n", tab->name);
   while (tab)
@@ -303,17 +327,23 @@ rt_prune(rtable *tab)
 	{
 	  net *n = (net *) f;
 	  rte *e;
-	  for (e=n->routes; e; e=e->next)
+	  ncnt++;
+	  for (e=n->routes; e; e=e->next, rcnt++)
 	    if (e->attrs->proto->core_state != FS_HAPPY)
 	      {
-		FIB_ITERATE_PUT(&fit, f);
 		rte_discard(e);
-		cnt++;
-		goto again;
+		rdel++;
 	      }
+	  if (!n->routes)		/* Orphaned FIB entry? */
+	    {
+	      FIB_ITERATE_PUT(&fit, f);
+	      fib_delete(&tab->fib, f);
+	      ndel++;
+	      goto again;
+	    }
 	}
       FIB_ITERATE_END(f);
       tab = tab->sibling;
     }
-  DBG("Pruned %d routes\n", cnt);
+  DBG("Pruned %d of %d routes and %d of %d networks\n", rcnt, rdel, ncnt, ndel);
 }