batman-adv: protect neighbor nodes with reference counters

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>

net/batman-adv/originator.c

@@ -59,9 +59,18 @@ err:
 	return 0;
 }
 
-struct neigh_node *
-create_neighbor(struct orig_node *orig_node, struct orig_node *orig_neigh_node,
-		uint8_t *neigh, struct batman_if *if_incoming)
+void neigh_node_free_ref(struct kref *refcount)
+{
+	struct neigh_node *neigh_node;
+
+	neigh_node = container_of(refcount, struct neigh_node, refcount);
+	kfree(neigh_node);
+}
+
+struct neigh_node *create_neighbor(struct orig_node *orig_node,
+				   struct orig_node *orig_neigh_node,
+				   uint8_t *neigh,
+				   struct batman_if *if_incoming)
 {
 	struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct neigh_node *neigh_node;
@@ -78,6 +87,7 @@ create_neighbor(struct orig_node *orig_node, struct orig_node *orig_neigh_node,
 	memcpy(neigh_node->addr, neigh, ETH_ALEN);
 	neigh_node->orig_node = orig_neigh_node;
 	neigh_node->if_incoming = if_incoming;
+	kref_init(&neigh_node->refcount);
 
 	list_add_tail(&neigh_node->list, &orig_node->neigh_list);
 	return neigh_node;
@@ -95,7 +105,7 @@ static void free_orig_node(void *data, void *arg)
 		neigh_node = list_entry(list_pos, struct neigh_node, list);
 
 		list_del(list_pos);
-		kfree(neigh_node);
+		kref_put(&neigh_node->refcount, neigh_node_free_ref);
 	}
 
 	frag_list_free(&orig_node->frag_list);
@@ -216,7 +226,7 @@ static bool purge_orig_neighbors(struct bat_priv *bat_priv,
 
 			neigh_purged = true;
 			list_del(list_pos);
-			kfree(neigh_node);
+			kref_put(&neigh_node->refcount, neigh_node_free_ref);
 		} else {
 			if ((!*best_neigh_node) ||
 			    (neigh_node->tq_avg > (*best_neigh_node)->tq_avg))

net/batman-adv/originator.h

@@ -26,9 +26,11 @@ int originator_init(struct bat_priv *bat_priv);
 void originator_free(struct bat_priv *bat_priv);
 void purge_orig_ref(struct bat_priv *bat_priv);
 struct orig_node *get_orig_node(struct bat_priv *bat_priv, uint8_t *addr);
-struct neigh_node *
-create_neighbor(struct orig_node *orig_node, struct orig_node *orig_neigh_node,
-		uint8_t *neigh, struct batman_if *if_incoming);
+struct neigh_node *create_neighbor(struct orig_node *orig_node,
+				   struct orig_node *orig_neigh_node,
+				   uint8_t *neigh,
+				   struct batman_if *if_incoming);
+void neigh_node_free_ref(struct kref *refcount);
 int orig_seq_print_text(struct seq_file *seq, void *offset);
 int orig_hash_add_if(struct batman_if *batman_if, int max_if_num);
 int orig_hash_del_if(struct batman_if *batman_if, int max_if_num);

net/batman-adv/routing.c

@@ -89,6 +89,8 @@ static void update_route(struct bat_priv *bat_priv,
 			 struct neigh_node *neigh_node,
 			 unsigned char *hna_buff, int hna_buff_len)
 {
+	struct neigh_node *neigh_node_tmp;
+
 	/* route deleted */
 	if ((orig_node->router) && (!neigh_node)) {
 
@@ -115,7 +117,12 @@ static void update_route(struct bat_priv *bat_priv,
 			orig_node->router->addr);
 	}
 
+	if (neigh_node)
+		kref_get(&neigh_node->refcount);
+	neigh_node_tmp = orig_node->router;
 	orig_node->router = neigh_node;
+	if (neigh_node_tmp)
+		kref_put(&neigh_node_tmp->refcount, neigh_node_free_ref);
 }
 
 

net/batman-adv/types.h

@@ -115,6 +115,7 @@ struct neigh_node {
 	struct neigh_node *next_bond_candidate;
 	unsigned long last_valid;
 	unsigned long real_bits[NUM_WORDS];
+	struct kref refcount;
 	struct orig_node *orig_node;
 	struct batman_if *if_incoming;
 };