[ospfd] Allow ospf_lsa_unlock to NULL out callers' LSA pointers upon free

2006-07-26 Paul Jakma <paul.jakma@sun.com>

	* ospf_lsa.{c,h}: (ospf_lsa_unlock) Change to take a double pointer
	  to the LSA to be 'unlocked', so that, if the LSA is freed, the
	  callers pointer to the LSA can be NULLed out, allowing any further
	  use of that pointer to provoke a crash sooner rather than later.
	* ospf_*.c: (general) Adjust callers of ospf_lsa_unlock to match
	  previous. Try annotate 'locking' somewhat to show which 'locks'
	  are protecting what LSA reference, if not obvious.
	* ospf_opaque.c: (ospf_opaque_lsa_install) Trivial: remove useless
	  goto, replace with return.
	* ospf_packet.c: (ospf_make_ls_ack) Trivial: merge two list loops,
	  the dual-loop predated the delete-safe list-loop macro.

1 files changed, 23 insertions, 21 deletions

diff --git a/ospfd/ospf_lsa.c b/ospfd/ospf_lsa.c
index 8b5c6eb8..b99b931c 100644
--- a/ospfd/ospf_lsa.c
+++ b/ospfd/ospf_lsa.c
@@ -294,20 +294,21 @@ ospf_lsa_lock (struct ospf_lsa *lsa)
 
 /* Unlock LSA. */
 void
-ospf_lsa_unlock (struct ospf_lsa *lsa)
+ospf_lsa_unlock (struct ospf_lsa **lsa)
 {
   /* This is sanity check. */
-  if (!lsa)
+  if (!lsa || !*lsa)
     return;
   
-  lsa->lock--;
+  (*lsa)->lock--;
 
-  assert (lsa->lock >= 0);
+  assert ((*lsa)->lock >= 0);
 
-  if (lsa->lock == 0)
+  if ((*lsa)->lock == 0)
     {
-      assert (CHECK_FLAG (lsa->flags, OSPF_LSA_DISCARD));
-      ospf_lsa_free (lsa);
+      assert (CHECK_FLAG ((*lsa)->flags, OSPF_LSA_DISCARD));
+      ospf_lsa_free (*lsa);
+      *lsa = NULL;
     }
 }
 
@@ -318,7 +319,7 @@ ospf_lsa_discard (struct ospf_lsa *lsa)
   if (!CHECK_FLAG (lsa->flags, OSPF_LSA_DISCARD))
     {
       SET_FLAG (lsa->flags, OSPF_LSA_DISCARD);
-      ospf_lsa_unlock (lsa);
+      ospf_lsa_unlock (&lsa);
     }
 }
 
@@ -1044,7 +1045,7 @@ ospf_router_lsa_update_timer (struct thread *thread)
 	    zlog_debug("LSA[Type%d:%s]: Refresh router-LSA for Area %s",
 		      lsa->data->type, inet_ntoa (lsa->data->id), area_str);
 	  ospf_lsa_flush_area (lsa, area);
-	  ospf_lsa_unlock (area->router_lsa_self);
+	  ospf_lsa_unlock (&area->router_lsa_self);
 	  area->router_lsa_self = NULL;
 
 	  /* Refresh router-LSA, (not install) and flood through area. */
@@ -1850,7 +1851,7 @@ ospf_install_flood_nssa (struct ospf *ospf,
 	  {
 	    if (IS_DEBUG_OSPF_NSSA)
 	      zlog_debug ("LSA[Type-7]: Could not build FWD-ADDR");
-	    ospf_lsa_discard(new);
+	    ospf_lsa_discard (new);
 	    return;
 	  }
 	}
@@ -2518,7 +2519,7 @@ ospf_router_lsa_install (struct ospf *ospf,
                           ospf_router_lsa_timer, OSPF_LS_REFRESH_TIME);
       
       /* Set self-originated router-LSA. */
-      ospf_lsa_unlock (area->router_lsa_self);
+      ospf_lsa_unlock (&area->router_lsa_self);
       area->router_lsa_self = ospf_lsa_lock (new);
 
       if (IS_DEBUG_OSPF (lsa, LSA_INSTALL))
@@ -2562,7 +2563,7 @@ ospf_network_lsa_install (struct ospf *ospf,
 			       ospf_network_lsa_refresh_timer,
 			       OSPF_LS_REFRESH_TIME);
 
-      ospf_lsa_unlock (oi->network_lsa_self);
+      ospf_lsa_unlock (&oi->network_lsa_self);
       oi->network_lsa_self = ospf_lsa_lock (new);
     }
 
@@ -3067,7 +3068,7 @@ ospf_lsa_maxage_delete (struct ospf *ospf, struct ospf_lsa *lsa)
   if ((n = listnode_lookup (ospf->maxage_lsa, lsa)))
     {
       list_delete_node (ospf->maxage_lsa, n);
-      ospf_lsa_unlock (lsa);
+      ospf_lsa_unlock (&lsa); /* maxage_lsa */
     }
 }
 
@@ -3482,7 +3483,7 @@ ospf_flush_self_originated_lsas_now (struct ospf *ospf)
             zlog_debug ("LSA[Type%d:%s]: Schedule self-originated LSA to FLUSH", lsa->data->type, inet_ntoa (lsa->data->id));
 
           ospf_lsa_flush_area (lsa, area);
-          ospf_lsa_unlock (area->router_lsa_self);
+          ospf_lsa_unlock (&area->router_lsa_self);
           area->router_lsa_self = NULL;
           OSPF_TIMER_OFF (area->t_router_lsa_self);
         }
@@ -3497,7 +3498,7 @@ ospf_flush_self_originated_lsas_now (struct ospf *ospf)
                 zlog_debug ("LSA[Type%d:%s]: Schedule self-originated LSA to FLUSH", lsa->data->type, inet_ntoa (lsa->data->id));
 
               ospf_lsa_flush_area (oi->network_lsa_self, area);
-              ospf_lsa_unlock (oi->network_lsa_self);
+              ospf_lsa_unlock (&oi->network_lsa_self);
               oi->network_lsa_self = NULL;
               OSPF_TIMER_OFF (oi->t_network_lsa_self);
             }
@@ -3666,7 +3667,7 @@ ospf_lsa_action (struct thread *t)
       break;
     }
 
-  ospf_lsa_unlock (data->lsa);
+  ospf_lsa_unlock (&data->lsa); /* Message */
   XFREE (MTYPE_OSPF_MESSAGE, data);
   return 0;
 }
@@ -3681,7 +3682,7 @@ ospf_schedule_lsa_flood_area (struct ospf_area *area, struct ospf_lsa *lsa)
 
   data->action = LSA_ACTION_FLOOD_AREA;
   data->area = area;
-  data->lsa  = ospf_lsa_lock (lsa);
+  data->lsa  = ospf_lsa_lock (lsa); /* Message / Flood area */
 
   thread_add_event (master, ospf_lsa_action, data, 0);
 }
@@ -3696,7 +3697,7 @@ ospf_schedule_lsa_flush_area (struct ospf_area *area, struct ospf_lsa *lsa)
 
   data->action = LSA_ACTION_FLUSH_AREA;
   data->area = area;
-  data->lsa  = ospf_lsa_lock (lsa);
+  data->lsa  = ospf_lsa_lock (lsa); /* Message / Flush area */
 
   thread_add_event (master, ospf_lsa_action, data, 0);
 }
@@ -3779,7 +3780,8 @@ ospf_refresher_register_lsa (struct ospf *ospf, struct ospf_lsa *lsa)
 		   inet_ntoa (lsa->data->id), LS_AGE (lsa), index);
       if (!ospf->lsa_refresh_queue.qs[index])
 	ospf->lsa_refresh_queue.qs[index] = list_new ();
-      listnode_add (ospf->lsa_refresh_queue.qs[index], ospf_lsa_lock (lsa));
+      listnode_add (ospf->lsa_refresh_queue.qs[index],
+                    ospf_lsa_lock (lsa)); /* lsa_refresh_queue */
       lsa->refresh_list = index;
       if (IS_DEBUG_OSPF (lsa, LSA_REFRESH))
         zlog_debug ("LSA[Refresh:%s]: ospf_refresher_register_lsa(): "
@@ -3801,7 +3803,7 @@ ospf_refresher_unregister_lsa (struct ospf *ospf, struct ospf_lsa *lsa)
 	  list_free (refresh_list);
 	  ospf->lsa_refresh_queue.qs[lsa->refresh_list] = NULL;
 	}
-      ospf_lsa_unlock (lsa);
+      ospf_lsa_unlock (&lsa); /* lsa_refresh_queue */
       lsa->refresh_list = -1;
     }
 }
@@ -3855,7 +3857,7 @@ ospf_lsa_refresh_walker (struct thread *t)
 		           inet_ntoa (lsa->data->id), lsa, i);
 	      
 	      list_delete_node (refresh_list, node);
-	      ospf_lsa_unlock (lsa);
+	      ospf_lsa_unlock (&lsa); /* lsa_refresh_queue */
 	      lsa->refresh_list = -1;
 	      listnode_add (lsa_to_refresh, lsa);
 	    }