netfilter: nf_tables: use new transaction infrastructure to handle table

This patch speeds up rule-set updates and it also provides a way
to revert updates and leave things in consistent state in case that
the batch needs to be aborted.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -436,6 +436,16 @@ struct nft_trans_chain {
 #define nft_trans_chain_policy(trans)	\
 	(((struct nft_trans_chain *)trans->data)->policy)
 
+struct nft_trans_table {
+	bool		update;
+	bool		enable;
+};
+
+#define nft_trans_table_update(trans)	\
+	(((struct nft_trans_table *)trans->data)->update)
+#define nft_trans_table_enable(trans)	\
+	(((struct nft_trans_table *)trans->data)->enable)
+
 static inline struct nft_expr *nft_expr_first(const struct nft_rule *rule)
 {
 	return (struct nft_expr *)&rule->data[0];

net/netfilter/nf_tables_api.c

@@ -307,6 +307,9 @@ static int nf_tables_dump_tables(struct sk_buff *skb,
 	return skb->len;
 }
 
+/* Internal table flags */
+#define NFT_TABLE_INACTIVE	(1 << 15)
+
 static int nf_tables_gettable(struct sock *nlsk, struct sk_buff *skb,
 			      const struct nlmsghdr *nlh,
 			      const struct nlattr * const nla[])
@@ -333,6 +336,8 @@ static int nf_tables_gettable(struct sock *nlsk, struct sk_buff *skb,
 	table = nf_tables_table_lookup(afi, nla[NFTA_TABLE_NAME]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (table->flags & NFT_TABLE_INACTIVE)
+		return -ENOENT;
 
 	skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (!skb2)
@@ -395,9 +400,9 @@ static void nf_tables_table_disable(const struct nft_af_info *afi,
 
 static int nf_tables_updtable(struct nft_ctx *ctx)
 {
-	const struct nfgenmsg *nfmsg = nlmsg_data(ctx->nlh);
-	int family = nfmsg->nfgen_family, ret = 0;
+	struct nft_trans *trans;
 	u32 flags;
+	int ret = 0;
 
 	if (!ctx->nla[NFTA_TABLE_FLAGS])
 		return 0;
@@ -406,25 +411,48 @@ static int nf_tables_updtable(struct nft_ctx *ctx)
 	if (flags & ~NFT_TABLE_F_DORMANT)
 		return -EINVAL;
 
+	trans = nft_trans_alloc(ctx, NFT_MSG_NEWTABLE,
+				sizeof(struct nft_trans_table));
+	if (trans == NULL)
+		return -ENOMEM;
+
 	if ((flags & NFT_TABLE_F_DORMANT) &&
 	    !(ctx->table->flags & NFT_TABLE_F_DORMANT)) {
-		nf_tables_table_disable(ctx->afi, ctx->table);
-		ctx->table->flags |= NFT_TABLE_F_DORMANT;
+		nft_trans_table_enable(trans) = false;
 	} else if (!(flags & NFT_TABLE_F_DORMANT) &&
 		   ctx->table->flags & NFT_TABLE_F_DORMANT) {
 		ret = nf_tables_table_enable(ctx->afi, ctx->table);
-		if (ret >= 0)
+		if (ret >= 0) {
 			ctx->table->flags &= ~NFT_TABLE_F_DORMANT;
+			nft_trans_table_enable(trans) = true;
+		}
 	}
 	if (ret < 0)
 		goto err;
 
-	nf_tables_table_notify(ctx->skb, ctx->nlh, ctx->table,
-			       NFT_MSG_NEWTABLE, family);
+	nft_trans_table_update(trans) = true;
+	list_add_tail(&trans->list, &ctx->net->nft.commit_list);
+	return 0;
 err:
+	nft_trans_destroy(trans);
 	return ret;
 }
 
+static int nft_trans_table_add(struct nft_ctx *ctx, int msg_type)
+{
+	struct nft_trans *trans;
+
+	trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_table));
+	if (trans == NULL)
+		return -ENOMEM;
+
+	if (msg_type == NFT_MSG_NEWTABLE)
+		ctx->table->flags |= NFT_TABLE_INACTIVE;
+
+	list_add_tail(&trans->list, &ctx->net->nft.commit_list);
+	return 0;
+}
+
 static int nf_tables_newtable(struct sock *nlsk, struct sk_buff *skb,
 			      const struct nlmsghdr *nlh,
 			      const struct nlattr * const nla[])
@@ -437,6 +465,7 @@ static int nf_tables_newtable(struct sock *nlsk, struct sk_buff *skb,
 	int family = nfmsg->nfgen_family;
 	u32 flags = 0;
 	struct nft_ctx ctx;
+	int err;
 
 	afi = nf_tables_afinfo_lookup(net, family, true);
 	if (IS_ERR(afi))
@@ -451,6 +480,8 @@ static int nf_tables_newtable(struct sock *nlsk, struct sk_buff *skb,
 	}
 
 	if (table != NULL) {
+		if (table->flags & NFT_TABLE_INACTIVE)
+			return -ENOENT;
 		if (nlh->nlmsg_flags & NLM_F_EXCL)
 			return -EEXIST;
 		if (nlh->nlmsg_flags & NLM_F_REPLACE)
@@ -480,8 +511,14 @@ static int nf_tables_newtable(struct sock *nlsk, struct sk_buff *skb,
 	INIT_LIST_HEAD(&table->sets);
 	table->flags = flags;
 
+	nft_ctx_init(&ctx, skb, nlh, afi, table, NULL, nla);
+	err = nft_trans_table_add(&ctx, NFT_MSG_NEWTABLE);
+	if (err < 0) {
+		kfree(table);
+		module_put(afi->owner);
+		return err;
+	}
 	list_add_tail(&table->list, &afi->tables);
-	nf_tables_table_notify(skb, nlh, table, NFT_MSG_NEWTABLE, family);
 	return 0;
 }
 
@@ -493,7 +530,8 @@ static int nf_tables_deltable(struct sock *nlsk, struct sk_buff *skb,
 	struct nft_af_info *afi;
 	struct nft_table *table;
 	struct net *net = sock_net(skb->sk);
-	int family = nfmsg->nfgen_family;
+	int family = nfmsg->nfgen_family, err;
+	struct nft_ctx ctx;
 
 	afi = nf_tables_afinfo_lookup(net, family, false);
 	if (IS_ERR(afi))
@@ -502,17 +540,27 @@ static int nf_tables_deltable(struct sock *nlsk, struct sk_buff *skb,
 	table = nf_tables_table_lookup(afi, nla[NFTA_TABLE_NAME]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (table->flags & NFT_TABLE_INACTIVE)
+		return -ENOENT;
 
 	if (!list_empty(&table->chains) || !list_empty(&table->sets))
 		return -EBUSY;
 
+	nft_ctx_init(&ctx, skb, nlh, afi, table, NULL, nla);
+	err = nft_trans_table_add(&ctx, NFT_MSG_DELTABLE);
+	if (err < 0)
+		return err;
+
 	list_del(&table->list);
-	nf_tables_table_notify(skb, nlh, table, NFT_MSG_DELTABLE, family);
-	kfree(table);
-	module_put(afi->owner);
 	return 0;
 }
 
+static void nf_tables_table_destroy(struct nft_ctx *ctx)
+{
+	kfree(ctx->table);
+	module_put(ctx->afi->owner);
+}
+
 int nft_register_chain_type(const struct nf_chain_type *ctype)
 {
 	int err = 0;
@@ -776,6 +824,8 @@ static int nf_tables_getchain(struct sock *nlsk, struct sk_buff *skb,
 	table = nf_tables_table_lookup(afi, nla[NFTA_CHAIN_TABLE]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (table->flags & NFT_TABLE_INACTIVE)
+		return -ENOENT;
 
 	chain = nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME]);
 	if (IS_ERR(chain))
@@ -1120,6 +1170,8 @@ static int nf_tables_delchain(struct sock *nlsk, struct sk_buff *skb,
 	table = nf_tables_table_lookup(afi, nla[NFTA_CHAIN_TABLE]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (table->flags & NFT_TABLE_INACTIVE)
+		return -ENOENT;
 
 	chain = nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME]);
 	if (IS_ERR(chain))
@@ -1573,6 +1625,8 @@ static int nf_tables_getrule(struct sock *nlsk, struct sk_buff *skb,
 	table = nf_tables_table_lookup(afi, nla[NFTA_RULE_TABLE]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (table->flags & NFT_TABLE_INACTIVE)
+		return -ENOENT;
 
 	chain = nf_tables_chain_lookup(table, nla[NFTA_RULE_CHAIN]);
 	if (IS_ERR(chain))
@@ -1838,6 +1892,8 @@ static int nf_tables_delrule(struct sock *nlsk, struct sk_buff *skb,
 	table = nf_tables_table_lookup(afi, nla[NFTA_RULE_TABLE]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (table->flags & NFT_TABLE_INACTIVE)
+		return -ENOENT;
 
 	if (nla[NFTA_RULE_CHAIN]) {
 		chain = nf_tables_chain_lookup(table, nla[NFTA_RULE_CHAIN]);
@@ -2004,6 +2060,8 @@ static int nft_ctx_init_from_setattr(struct nft_ctx *ctx,
 		table = nf_tables_table_lookup(afi, nla[NFTA_SET_TABLE]);
 		if (IS_ERR(table))
 			return PTR_ERR(table);
+		if (table->flags & NFT_TABLE_INACTIVE)
+			return -ENOENT;
 	}
 
 	nft_ctx_init(ctx, skb, nlh, afi, table, NULL, nla);
@@ -2681,7 +2739,8 @@ static const struct nla_policy nft_set_elem_list_policy[NFTA_SET_ELEM_LIST_MAX +
 static int nft_ctx_init_from_elemattr(struct nft_ctx *ctx,
 				      const struct sk_buff *skb,
 				      const struct nlmsghdr *nlh,
-				      const struct nlattr * const nla[])
+				      const struct nlattr * const nla[],
+				      bool trans)
 {
 	const struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 	struct nft_af_info *afi;
@@ -2695,6 +2754,8 @@ static int nft_ctx_init_from_elemattr(struct nft_ctx *ctx,
 	table = nf_tables_table_lookup(afi, nla[NFTA_SET_ELEM_LIST_TABLE]);
 	if (IS_ERR(table))
 		return PTR_ERR(table);
+	if (!trans && (table->flags & NFT_TABLE_INACTIVE))
+		return -ENOENT;
 
 	nft_ctx_init(ctx, skb, nlh, afi, table, NULL, nla);
 	return 0;
@@ -2768,7 +2829,8 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb)
 	if (err < 0)
 		return err;
 
-	err = nft_ctx_init_from_elemattr(&ctx, cb->skb, cb->nlh, (void *)nla);
+	err = nft_ctx_init_from_elemattr(&ctx, cb->skb, cb->nlh, (void *)nla,
+					 false);
 	if (err < 0)
 		return err;
 
@@ -2833,7 +2895,7 @@ static int nf_tables_getsetelem(struct sock *nlsk, struct sk_buff *skb,
 	struct nft_ctx ctx;
 	int err;
 
-	err = nft_ctx_init_from_elemattr(&ctx, skb, nlh, nla);
+	err = nft_ctx_init_from_elemattr(&ctx, skb, nlh, nla, false);
 	if (err < 0)
 		return err;
 
@@ -3033,7 +3095,7 @@ static int nf_tables_newsetelem(struct sock *nlsk, struct sk_buff *skb,
 	struct nft_ctx ctx;
 	int rem, err;
 
-	err = nft_ctx_init_from_elemattr(&ctx, skb, nlh, nla);
+	err = nft_ctx_init_from_elemattr(&ctx, skb, nlh, nla, true);
 	if (err < 0)
 		return err;
 
@@ -3111,7 +3173,7 @@ static int nf_tables_delsetelem(struct sock *nlsk, struct sk_buff *skb,
 	struct nft_ctx ctx;
 	int rem, err;
 
-	err = nft_ctx_init_from_elemattr(&ctx, skb, nlh, nla);
+	err = nft_ctx_init_from_elemattr(&ctx, skb, nlh, nla, false);
 	if (err < 0)
 		return err;
 
@@ -3131,7 +3193,7 @@ static int nf_tables_delsetelem(struct sock *nlsk, struct sk_buff *skb,
 
 static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
 	[NFT_MSG_NEWTABLE] = {
-		.call		= nf_tables_newtable,
+		.call_batch	= nf_tables_newtable,
 		.attr_count	= NFTA_TABLE_MAX,
 		.policy		= nft_table_policy,
 	},
@@ -3141,7 +3203,7 @@ static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
 		.policy		= nft_table_policy,
 	},
 	[NFT_MSG_DELTABLE] = {
-		.call		= nf_tables_deltable,
+		.call_batch	= nf_tables_deltable,
 		.attr_count	= NFTA_TABLE_MAX,
 		.policy		= nft_table_policy,
 	},
@@ -3246,6 +3308,28 @@ static int nf_tables_commit(struct sk_buff *skb)
 
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
 		switch (trans->msg_type) {
+		case NFT_MSG_NEWTABLE:
+			if (nft_trans_table_update(trans)) {
+				if (!nft_trans_table_enable(trans)) {
+					nf_tables_table_disable(trans->ctx.afi,
+								trans->ctx.table);
+					trans->ctx.table->flags |= NFT_TABLE_F_DORMANT;
+				}
+			} else {
+				trans->ctx.table->flags &= ~NFT_TABLE_INACTIVE;
+			}
+			nf_tables_table_notify(trans->ctx.skb, trans->ctx.nlh,
+					       trans->ctx.table,
+					       NFT_MSG_NEWTABLE,
+					       trans->ctx.afi->family);
+			nft_trans_destroy(trans);
+			break;
+		case NFT_MSG_DELTABLE:
+			nf_tables_table_notify(trans->ctx.skb, trans->ctx.nlh,
+					       trans->ctx.table,
+					       NFT_MSG_DELTABLE,
+					       trans->ctx.afi->family);
+			break;
 		case NFT_MSG_NEWCHAIN:
 			if (nft_trans_chain_update(trans))
 				nft_chain_commit_update(trans);
@@ -3310,6 +3394,9 @@ static int nf_tables_commit(struct sk_buff *skb)
 	/* Now we can safely release unused old rules */
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
 		switch (trans->msg_type) {
+		case NFT_MSG_DELTABLE:
+			nf_tables_table_destroy(&trans->ctx);
+			break;
 		case NFT_MSG_DELCHAIN:
 			nf_tables_chain_destroy(trans->ctx.chain);
 			break;
@@ -3334,6 +3421,23 @@ static int nf_tables_abort(struct sk_buff *skb)
 
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
 		switch (trans->msg_type) {
+		case NFT_MSG_NEWTABLE:
+			if (nft_trans_table_update(trans)) {
+				if (nft_trans_table_enable(trans)) {
+					nf_tables_table_disable(trans->ctx.afi,
+								trans->ctx.table);
+					trans->ctx.table->flags |= NFT_TABLE_F_DORMANT;
+				}
+				nft_trans_destroy(trans);
+			} else {
+				list_del(&trans->ctx.table->list);
+			}
+			break;
+		case NFT_MSG_DELTABLE:
+			list_add_tail(&trans->ctx.table->list,
+				      &trans->ctx.afi->tables);
+			nft_trans_destroy(trans);
+			break;
 		case NFT_MSG_NEWCHAIN:
 			if (nft_trans_chain_update(trans)) {
 				if (nft_trans_chain_stats(trans))
@@ -3377,6 +3481,9 @@ static int nf_tables_abort(struct sk_buff *skb)
 
 	list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
 		switch (trans->msg_type) {
+		case NFT_MSG_NEWTABLE:
+			nf_tables_table_destroy(&trans->ctx);
+			break;
 		case NFT_MSG_NEWCHAIN:
 			nf_tables_chain_destroy(trans->ctx.chain);
 			break;