rule: add reference counter to the table object

We may hold multiple references to table objects in follow up patches when
adding object declarations to the cache.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 13 insertions, 0 deletions

diff --git a/include/rule.h b/include/rule.h
index adff92fb..4e688794 100644
--- a/include/rule.h
+++ b/include/rule.h
@@ -76,6 +76,7 @@ enum table_flags {
  * @chains:	chains contained in the table
  * @sets:	sets contained in the table
  * @flags:	table flags
+ * @refcnt:	table reference counter
  */
 struct table {
 	struct list_head	list;
@@ -85,9 +86,11 @@ struct table {
 	struct list_head	chains;
 	struct list_head	sets;
 	enum table_flags 	flags;
+	unsigned int		refcnt;
 };
 
 extern struct table *table_alloc(void);
+extern struct table *table_get(struct table *table);
 extern void table_free(struct table *table);
 extern void table_add_hash(struct table *table);
 extern struct table *table_lookup(const struct handle *h);
diff --git a/src/rule.c b/src/rule.c
index ba2bf66d..7701e211 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -588,6 +588,8 @@ struct table *table_alloc(void)
 	init_list_head(&table->chains);
 	init_list_head(&table->sets);
 	init_list_head(&table->scope.symbols);
+	table->refcnt = 1;
+
 	return table;
 }
 
@@ -595,6 +597,8 @@ void table_free(struct table *table)
 {
 	struct chain *chain, *next;
 
+	if (--table->refcnt > 0)
+		return;
 	list_for_each_entry_safe(chain, next, &table->chains, list)
 		chain_free(chain);
 	handle_free(&table->handle);
@@ -602,6 +606,12 @@ void table_free(struct table *table)
 	xfree(table);
 }
 
+struct table *table_get(struct table *table)
+{
+	table->refcnt++;
+	return table;
+}
+
 void table_add_hash(struct table *table)
 {
 	list_add_tail(&table->list, &table_list);