netfilter: nf_tables: add generic macros to check for generation mask

Thus, we can reuse these to check the genmask of any object type, not
only rules. This is required now that tables, chain and sets will get a
generation mask field too in follow up patches.

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

include/net/netfilter/nf_tables.h

@@ -969,6 +969,30 @@ static inline u8 nft_genmask_cur(const struct net *net)
 
 #define NFT_GENMASK_ANY		((1 << 0) | (1 << 1))
 
+/*
+ * Generic transaction helpers
+ */
+
+/* Check if this object is currently active. */
+#define nft_is_active(__net, __obj)				\
+	(((__obj)->genmask & nft_genmask_cur(__net)) == 0)
+
+/* Check if this object is active in the next generation. */
+#define nft_is_active_next(__net, __obj)			\
+	(((__obj)->genmask & nft_genmask_next(__net)) == 0)
+
+/* This object becomes active in the next generation. */
+#define nft_activate_next(__net, __obj)				\
+	(__obj)->genmask = nft_genmask_cur(__net)
+
+/* This object becomes inactive in the next generation. */
+#define nft_deactivate_next(__net, __obj)			\
+        (__obj)->genmask = nft_genmask_next(__net)
+
+/* After committing the ruleset, clear the stale generation bit. */
+#define nft_clear(__net, __obj)					\
+	(__obj)->genmask &= ~nft_genmask_next(__net)
+
 /*
  * Set element transaction helpers
  */

net/netfilter/nf_tables_api.c

@@ -234,42 +234,12 @@ static int nft_delchain(struct nft_ctx *ctx)
 	return err;
 }
 
-static inline bool
-nft_rule_is_active(struct net *net, const struct nft_rule *rule)
-{
-	return (rule->genmask & nft_genmask_cur(net)) == 0;
-}
-
-static inline int
-nft_rule_is_active_next(struct net *net, const struct nft_rule *rule)
-{
-	return (rule->genmask & nft_genmask_next(net)) == 0;
-}
-
-static inline void
-nft_rule_activate_next(struct net *net, struct nft_rule *rule)
-{
-	/* Now inactive, will be active in the future */
-	rule->genmask = nft_genmask_cur(net);
-}
-
-static inline void
-nft_rule_deactivate_next(struct net *net, struct nft_rule *rule)
-{
-	rule->genmask = nft_genmask_next(net);
-}
-
-static inline void nft_rule_clear(struct net *net, struct nft_rule *rule)
-{
-	rule->genmask &= ~nft_genmask_next(net);
-}
-
 static int
 nf_tables_delrule_deactivate(struct nft_ctx *ctx, struct nft_rule *rule)
 {
 	/* You cannot delete the same rule twice */
-	if (nft_rule_is_active_next(ctx->net, rule)) {
-		nft_rule_deactivate_next(ctx->net, rule);
+	if (nft_is_active_next(ctx->net, rule)) {
+		nft_deactivate_next(ctx->net, rule);
 		ctx->chain->use--;
 		return 0;
 	}
@@ -1898,7 +1868,7 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
 		list_for_each_entry_rcu(table, &afi->tables, list) {
 			list_for_each_entry_rcu(chain, &table->chains, list) {
 				list_for_each_entry_rcu(rule, &chain->rules, list) {
-					if (!nft_rule_is_active(net, rule))
+					if (!nft_is_active(net, rule))
 						goto cont;
 					if (idx < s_idx)
 						goto cont;
@@ -2102,7 +2072,7 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 	if (rule == NULL)
 		goto err1;
 
-	nft_rule_activate_next(net, rule);
+	nft_activate_next(net, rule);
 
 	rule->handle = handle;
 	rule->dlen   = size;
@@ -2124,14 +2094,14 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 	}
 
 	if (nlh->nlmsg_flags & NLM_F_REPLACE) {
-		if (nft_rule_is_active_next(net, old_rule)) {
+		if (nft_is_active_next(net, old_rule)) {
 			trans = nft_trans_rule_add(&ctx, NFT_MSG_DELRULE,
 						   old_rule);
 			if (trans == NULL) {
 				err = -ENOMEM;
 				goto err2;
 			}
-			nft_rule_deactivate_next(net, old_rule);
+			nft_deactivate_next(net, old_rule);
 			chain->use--;
 			list_add_tail_rcu(&rule->list, &old_rule->list);
 		} else {
@@ -3980,7 +3950,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
 						   trans->ctx.afi->nops);
 			break;
 		case NFT_MSG_NEWRULE:
-			nft_rule_clear(trans->ctx.net, nft_trans_rule(trans));
+			nft_clear(trans->ctx.net, nft_trans_rule(trans));
 			nf_tables_rule_notify(&trans->ctx,
 					      nft_trans_rule(trans),
 					      NFT_MSG_NEWRULE);
@@ -4116,7 +4086,7 @@ static int nf_tables_abort(struct net *net, struct sk_buff *skb)
 			break;
 		case NFT_MSG_DELRULE:
 			trans->ctx.chain->use++;
-			nft_rule_clear(trans->ctx.net, nft_trans_rule(trans));
+			nft_clear(trans->ctx.net, nft_trans_rule(trans));
 			nft_trans_destroy(trans);
 			break;
 		case NFT_MSG_NEWSET: