netfilter: nf_tables: add message type to transactions

The patch adds message type to the transaction to simplify the
commit the and abort routines. Yet another step forward in the
generalisation of the transaction infrastructure.

Signed-off-by: Pablo Neira Ayuso <[email protected]>

Author: ummakynes

include/net/netfilter/nf_tables.h

@@ -390,11 +390,13 @@ struct nft_rule {
  *	struct nft_trans - nf_tables object update in transaction
  *
  *	@list: used internally
+ *	@msg_type: message type
  *	@ctx: transaction context
  *	@data: internal information related to the transaction
  */
 struct nft_trans {
 	struct list_head		list;
+	int				msg_type;
 	struct nft_ctx			ctx;
 	char				data[0];
 };

net/netfilter/nf_tables_api.c

@@ -105,14 +105,16 @@ static void nft_ctx_init(struct nft_ctx *ctx,
 	ctx->nla   = nla;
 }
 
-static struct nft_trans *nft_trans_alloc(struct nft_ctx *ctx, u32 size)
+static struct nft_trans *nft_trans_alloc(struct nft_ctx *ctx, int msg_type,
+					 u32 size)
 {
 	struct nft_trans *trans;
 
 	trans = kzalloc(sizeof(struct nft_trans) + size, GFP_KERNEL);
 	if (trans == NULL)
 		return NULL;
 
+	trans->msg_type = msg_type;
 	trans->ctx	= *ctx;
 
 	return trans;
@@ -1576,12 +1578,12 @@ static void nf_tables_rule_destroy(const struct nft_ctx *ctx,
 	kfree(rule);
 }
 
-static struct nft_trans *nft_trans_rule_add(struct nft_ctx *ctx,
+static struct nft_trans *nft_trans_rule_add(struct nft_ctx *ctx, int msg_type,
 					    struct nft_rule *rule)
 {
 	struct nft_trans *trans;
 
-	trans = nft_trans_alloc(ctx, sizeof(struct nft_trans_rule));
+	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_rule));
 	if (trans == NULL)
 		return NULL;
 
@@ -1703,7 +1705,8 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
 
 	if (nlh->nlmsg_flags & NLM_F_REPLACE) {
 		if (nft_rule_is_active_next(net, old_rule)) {
-			trans = nft_trans_rule_add(&ctx, old_rule);
+			trans = nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE,
+						   old_rule);
 			if (trans == NULL) {
 				err = -ENOMEM;
 				goto err2;
@@ -1726,7 +1729,7 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
 			list_add_rcu(&rule->list, &chain->rules);
 	}
 
-	if (nft_trans_rule_add(&ctx, rule) == NULL) {
+	if (nft_trans_rule_add(&ctx, NFT_MSG_NEWRULE, rule) == NULL) {
 		err = -ENOMEM;
 		goto err3;
 	}
@@ -1754,7 +1757,7 @@ nf_tables_delrule_one(struct nft_ctx *ctx, struct nft_rule *rule)
 {
 	/* You cannot delete the same rule twice */
 	if (nft_rule_is_active_next(ctx->net, rule)) {
-		if (nft_trans_rule_add(ctx, rule) == NULL)
+		if (nft_trans_rule_add(ctx, NFT_MSG_DELRULE, rule) == NULL)
 			return -ENOMEM;
 		nft_rule_disactivate_next(ctx->net, rule);
 		return 0;
@@ -3114,37 +3117,40 @@ static int nf_tables_commit(struct sk_buff *skb)
 	synchronize_rcu();
 
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
-		/* This rule was inactive in the past and just became active.
-		 * Clear the next bit of the genmask since its meaning has
-		 * changed, now it is the future.
-		 */
-		if (nft_rule_is_active(net, nft_trans_rule(trans))) {
-			nft_rule_clear(net, nft_trans_rule(trans));
-			nf_tables_rule_notify(skb, trans->ctx.nlh,
+		switch (trans->msg_type) {
+		case NFT_MSG_NEWRULE:
+			nft_rule_clear(trans->ctx.net, nft_trans_rule(trans));
+			nf_tables_rule_notify(trans->ctx.skb, trans->ctx.nlh,
 					      trans->ctx.table,
 					      trans->ctx.chain,
 					      nft_trans_rule(trans),
 					      NFT_MSG_NEWRULE, 0,
 					      trans->ctx.afi->family);
 			nft_trans_destroy(trans);
-			continue;
+			break;
+		case NFT_MSG_DELRULE:
+			list_del_rcu(&nft_trans_rule(trans)->list);
+			nf_tables_rule_notify(trans->ctx.skb, trans->ctx.nlh,
+					      trans->ctx.table,
+					      trans->ctx.chain,
+					      nft_trans_rule(trans), NFT_MSG_DELRULE, 0,
+					      trans->ctx.afi->family);
+			break;
 		}
-
-		/* This rule is in the past, get rid of it */
-		list_del_rcu(&nft_trans_rule(trans)->list);
-		nf_tables_rule_notify(skb, trans->ctx.nlh,
-				      trans->ctx.table, trans->ctx.chain,
-				      nft_trans_rule(trans), NFT_MSG_DELRULE,
-				      0, trans->ctx.afi->family);
 	}
 
 	/* Make sure we don't see any packet traversing old rules */
 	synchronize_rcu();
 
 	/* Now we can safely release unused old rules */
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
-		nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans));
-		nft_trans_destroy(trans);
+		switch (trans->msg_type) {
+		case NFT_MSG_DELRULE:
+			nf_tables_rule_destroy(&trans->ctx,
+					       nft_trans_rule(trans));
+			nft_trans_destroy(trans);
+			break;
+		}
 	}
 
 	return 0;
@@ -3156,22 +3162,28 @@ static int nf_tables_abort(struct sk_buff *skb)
 	struct nft_trans *trans, *next;
 
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
-		if (!nft_rule_is_active_next(net, nft_trans_rule(trans))) {
-			nft_rule_clear(net, nft_trans_rule(trans));
+		switch (trans->msg_type) {
+		case NFT_MSG_NEWRULE:
+			list_del_rcu(&nft_trans_rule(trans)->list);
+			break;
+		case NFT_MSG_DELRULE:
+			nft_rule_clear(trans->ctx.net, nft_trans_rule(trans));
 			nft_trans_destroy(trans);
-			continue;
+			break;
 		}
-
-		/* This rule is inactive, get rid of it */
-		list_del_rcu(&nft_trans_rule(trans)->list);
 	}
 
 	/* Make sure we don't see any packet accessing aborted rules */
 	synchronize_rcu();
 
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
-		nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans));
-		nft_trans_destroy(trans);
+		switch (trans->msg_type) {
+		case NFT_MSG_NEWRULE:
+			nf_tables_rule_destroy(&trans->ctx,
+					       nft_trans_rule(trans));
+			nft_trans_destroy(trans);
+			break;
+		}
 	}
 
 	return 0;