netfilter: nf_tables: use new transaction infrastructure to handle chain

This patch speeds up rule-set updates and it also introduces a way to
revert chain updates if the batch is aborted. The idea is to store the
changes in the transaction to apply that in the commit step.

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

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 0f472d6..7b2361c 100644 (file)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -420,6 +420,22 @@ struct nft_trans_set {
 #define nft_trans_set_id(trans)        \
        (((struct nft_trans_set *)trans->data)->set_id)
 
+struct nft_trans_chain {
+       bool            update;
+       char            name[NFT_CHAIN_MAXNAMELEN];
+       struct nft_stats __percpu *stats;
+       u8              policy;
+};
+
+#define nft_trans_chain_update(trans)  \
+       (((struct nft_trans_chain *)trans->data)->update)
+#define nft_trans_chain_name(trans)    \
+       (((struct nft_trans_chain *)trans->data)->name)
+#define nft_trans_chain_stats(trans)   \
+       (((struct nft_trans_chain *)trans->data)->stats)
+#define nft_trans_chain_policy(trans)  \
+       (((struct nft_trans_chain *)trans->data)->policy)
+
 static inline struct nft_expr *nft_expr_first(const struct nft_rule *rule)
 {
        return (struct nft_expr *)&rule->data[0];
@@ -452,6 +468,7 @@ static inline void *nft_userdata(const struct nft_rule *rule)
 
 enum nft_chain_flags {
        NFT_BASE_CHAIN                  = 0x1,
+       NFT_CHAIN_INACTIVE              = 0x2,
 };
 
 /**

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 92cec68..7a1149f 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -782,6 +782,8 @@ static int nf_tables_getchain(struct sock *nlsk, struct sk_buff *skb,
        chain = nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME]);
        if (IS_ERR(chain))
                return PTR_ERR(chain);
+       if (chain->flags & NFT_CHAIN_INACTIVE)
+               return -ENOENT;
 
        skb2 = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
        if (!skb2)
@@ -847,6 +849,34 @@ static void nft_chain_stats_replace(struct nft_base_chain *chain,
                rcu_assign_pointer(chain->stats, newstats);
 }
 
+static int nft_trans_chain_add(struct nft_ctx *ctx, int msg_type)
+{
+       struct nft_trans *trans;
+
+       trans = nft_trans_alloc(ctx, msg_type, sizeof(struct nft_trans_chain));
+       if (trans == NULL)
+               return -ENOMEM;
+
+       if (msg_type == NFT_MSG_NEWCHAIN)
+               ctx->chain->flags |= NFT_CHAIN_INACTIVE;
+
+       list_add_tail(&trans->list, &ctx->net->nft.commit_list);
+       return 0;
+}
+
+static void nf_tables_chain_destroy(struct nft_chain *chain)
+{
+       BUG_ON(chain->use > 0);
+
+       if (chain->flags & NFT_BASE_CHAIN) {
+               module_put(nft_base_chain(chain)->type->owner);
+               free_percpu(nft_base_chain(chain)->stats);
+               kfree(nft_base_chain(chain));
+       } else {
+               kfree(chain);
+       }
+}
+
 static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
                              const struct nlmsghdr *nlh,
                              const struct nlattr * const nla[])
@@ -866,6 +896,7 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
        struct nft_stats __percpu *stats;
        int err;
        bool create;
+       struct nft_ctx ctx;
 
        create = nlh->nlmsg_flags & NLM_F_CREATE ? true : false;
 
@@ -911,6 +942,11 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
        }
 
        if (chain != NULL) {
+               struct nft_stats *stats = NULL;
+               struct nft_trans *trans;
+
+               if (chain->flags & NFT_CHAIN_INACTIVE)
+                       return -ENOENT;
                if (nlh->nlmsg_flags & NLM_F_EXCL)
                        return -EEXIST;
                if (nlh->nlmsg_flags & NLM_F_REPLACE)
@@ -927,17 +963,28 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
                        stats = nft_stats_alloc(nla[NFTA_CHAIN_COUNTERS]);
                        if (IS_ERR(stats))
                                return PTR_ERR(stats);
-
-                       nft_chain_stats_replace(nft_base_chain(chain), stats);
                }
 
-               if (nla[NFTA_CHAIN_POLICY])
-                       nft_base_chain(chain)->policy = policy;
+               nft_ctx_init(&ctx, skb, nlh, afi, table, chain, nla);
+               trans = nft_trans_alloc(&ctx, NFT_MSG_NEWCHAIN,
+                                       sizeof(struct nft_trans_chain));
+               if (trans == NULL)
+                       return -ENOMEM;
 
-               if (nla[NFTA_CHAIN_HANDLE] && name)
-                       nla_strlcpy(chain->name, name, NFT_CHAIN_MAXNAMELEN);
+               nft_trans_chain_stats(trans) = stats;
+               nft_trans_chain_update(trans) = true;
 
-               goto notify;
+               if (nla[NFTA_CHAIN_POLICY])
+                       nft_trans_chain_policy(trans) = policy;
+               else
+                       nft_trans_chain_policy(trans) = -1;
+
+               if (nla[NFTA_CHAIN_HANDLE] && name) {
+                       nla_strlcpy(nft_trans_chain_name(trans), name,
+                                   NFT_CHAIN_MAXNAMELEN);
+               }
+               list_add_tail(&trans->list, &net->nft.commit_list);
+               return 0;
        }
 
        if (table->use == UINT_MAX)
@@ -1033,31 +1080,26 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
        if (!(table->flags & NFT_TABLE_F_DORMANT) &&
            chain->flags & NFT_BASE_CHAIN) {
                err = nf_register_hooks(nft_base_chain(chain)->ops, afi->nops);
-               if (err < 0) {
-                       module_put(basechain->type->owner);
-                       free_percpu(basechain->stats);
-                       kfree(basechain);
-                       return err;
-               }
+               if (err < 0)
+                       goto err1;
        }
-       list_add_tail(&chain->list, &table->chains);
-       table->use++;
-notify:
-       nf_tables_chain_notify(skb, nlh, table, chain, NFT_MSG_NEWCHAIN,
-                              family);
-       return 0;
-}
 
-static void nf_tables_chain_destroy(struct nft_chain *chain)
-{
-       BUG_ON(chain->use > 0);
+       nft_ctx_init(&ctx, skb, nlh, afi, table, chain, nla);
+       err = nft_trans_chain_add(&ctx, NFT_MSG_NEWCHAIN);
+       if (err < 0)
+               goto err2;
 
-       if (chain->flags & NFT_BASE_CHAIN) {
-               module_put(nft_base_chain(chain)->type->owner);
-               free_percpu(nft_base_chain(chain)->stats);
-               kfree(nft_base_chain(chain));
-       } else
-               kfree(chain);
+       list_add_tail(&chain->list, &table->chains);
+       return 0;
+err2:
+       if (!(table->flags & NFT_TABLE_F_DORMANT) &&
+           chain->flags & NFT_BASE_CHAIN) {
+               nf_unregister_hooks(nft_base_chain(chain)->ops,
+                                   afi->nops);
+       }
+err1:
+       nf_tables_chain_destroy(chain);
+       return err;
 }
 
 static int nf_tables_delchain(struct sock *nlsk, struct sk_buff *skb,
@@ -1070,6 +1112,8 @@ static int nf_tables_delchain(struct sock *nlsk, struct sk_buff *skb,
        struct nft_chain *chain;
        struct net *net = sock_net(skb->sk);
        int family = nfmsg->nfgen_family;
+       struct nft_ctx ctx;
+       int err;
 
        afi = nf_tables_afinfo_lookup(net, family, false);
        if (IS_ERR(afi))
@@ -1082,24 +1126,17 @@ static int nf_tables_delchain(struct sock *nlsk, struct sk_buff *skb,
        chain = nf_tables_chain_lookup(table, nla[NFTA_CHAIN_NAME]);
        if (IS_ERR(chain))
                return PTR_ERR(chain);
-
+       if (chain->flags & NFT_CHAIN_INACTIVE)
+               return -ENOENT;
        if (!list_empty(&chain->rules) || chain->use > 0)
                return -EBUSY;
 
-       list_del(&chain->list);
-       table->use--;
-
-       if (!(table->flags & NFT_TABLE_F_DORMANT) &&
-           chain->flags & NFT_BASE_CHAIN)
-               nf_unregister_hooks(nft_base_chain(chain)->ops, afi->nops);
-
-       nf_tables_chain_notify(skb, nlh, table, chain, NFT_MSG_DELCHAIN,
-                              family);
-
-       /* Make sure all rule references are gone before this is released */
-       synchronize_rcu();
+       nft_ctx_init(&ctx, skb, nlh, afi, table, chain, nla);
+       err = nft_trans_chain_add(&ctx, NFT_MSG_DELCHAIN);
+       if (err < 0)
+               return err;
 
-       nf_tables_chain_destroy(chain);
+       list_del(&chain->list);
        return 0;
 }
 
@@ -1542,6 +1579,8 @@ static int nf_tables_getrule(struct sock *nlsk, struct sk_buff *skb,
        chain = nf_tables_chain_lookup(table, nla[NFTA_RULE_CHAIN]);
        if (IS_ERR(chain))
                return PTR_ERR(chain);
+       if (chain->flags & NFT_CHAIN_INACTIVE)
+               return -ENOENT;
 
        rule = nf_tables_rule_lookup(chain, nla[NFTA_RULE_HANDLE]);
        if (IS_ERR(rule))
@@ -3109,7 +3148,7 @@ static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
                .policy         = nft_table_policy,
        },
        [NFT_MSG_NEWCHAIN] = {
-               .call           = nf_tables_newchain,
+               .call_batch     = nf_tables_newchain,
                .attr_count     = NFTA_CHAIN_MAX,
                .policy         = nft_chain_policy,
        },
@@ -3119,7 +3158,7 @@ static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
                .policy         = nft_chain_policy,
        },
        [NFT_MSG_DELCHAIN] = {
-               .call           = nf_tables_delchain,
+               .call_batch     = nf_tables_delchain,
                .attr_count     = NFTA_CHAIN_MAX,
                .policy         = nft_chain_policy,
        },
@@ -3170,6 +3209,27 @@ static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
        },
 };
 
+static void nft_chain_commit_update(struct nft_trans *trans)
+{
+       struct nft_base_chain *basechain;
+
+       if (nft_trans_chain_name(trans)[0])
+               strcpy(trans->ctx.chain->name, nft_trans_chain_name(trans));
+
+       if (!(trans->ctx.chain->flags & NFT_BASE_CHAIN))
+               return;
+
+       basechain = nft_base_chain(trans->ctx.chain);
+       nft_chain_stats_replace(basechain, nft_trans_chain_stats(trans));
+
+       switch (nft_trans_chain_policy(trans)) {
+       case NF_DROP:
+       case NF_ACCEPT:
+               basechain->policy = nft_trans_chain_policy(trans);
+               break;
+       }
+}
+
 static int nf_tables_commit(struct sk_buff *skb)
 {
        struct net *net = sock_net(skb->sk);
@@ -3188,6 +3248,33 @@ 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_NEWCHAIN:
+                       if (nft_trans_chain_update(trans))
+                               nft_chain_commit_update(trans);
+                       else {
+                               trans->ctx.chain->flags &= ~NFT_CHAIN_INACTIVE;
+                               trans->ctx.table->use++;
+                       }
+                       nf_tables_chain_notify(trans->ctx.skb, trans->ctx.nlh,
+                                              trans->ctx.table,
+                                              trans->ctx.chain,
+                                              NFT_MSG_NEWCHAIN,
+                                              trans->ctx.afi->family);
+                       nft_trans_destroy(trans);
+                       break;
+               case NFT_MSG_DELCHAIN:
+                       trans->ctx.table->use--;
+                       nf_tables_chain_notify(trans->ctx.skb, trans->ctx.nlh,
+                                              trans->ctx.table,
+                                              trans->ctx.chain,
+                                              NFT_MSG_DELCHAIN,
+                                              trans->ctx.afi->family);
+                       if (!(trans->ctx.table->flags & NFT_TABLE_F_DORMANT) &&
+                           trans->ctx.chain->flags & NFT_BASE_CHAIN) {
+                               nf_unregister_hooks(nft_base_chain(trans->ctx.chain)->ops,
+                                                   trans->ctx.afi->nops);
+                       }
+                       break;
                case NFT_MSG_NEWRULE:
                        nft_rule_clear(trans->ctx.net, nft_trans_rule(trans));
                        nf_tables_rule_notify(trans->ctx.skb, trans->ctx.nlh,
@@ -3225,6 +3312,9 @@ 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_DELCHAIN:
+                       nf_tables_chain_destroy(trans->ctx.chain);
+                       break;
                case NFT_MSG_DELRULE:
                        nf_tables_rule_destroy(&trans->ctx,
                                               nft_trans_rule(trans));
@@ -3246,6 +3336,26 @@ 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_NEWCHAIN:
+                       if (nft_trans_chain_update(trans)) {
+                               if (nft_trans_chain_stats(trans))
+                                       free_percpu(nft_trans_chain_stats(trans));
+
+                               nft_trans_destroy(trans);
+                       } else {
+                               list_del(&trans->ctx.chain->list);
+                               if (!(trans->ctx.table->flags & NFT_TABLE_F_DORMANT) &&
+                                   trans->ctx.chain->flags & NFT_BASE_CHAIN) {
+                                       nf_unregister_hooks(nft_base_chain(trans->ctx.chain)->ops,
+                                                           trans->ctx.afi->nops);
+                               }
+                       }
+                       break;
+               case NFT_MSG_DELCHAIN:
+                       list_add_tail(&trans->ctx.chain->list,
+                                     &trans->ctx.table->chains);
+                       nft_trans_destroy(trans);
+                       break;
                case NFT_MSG_NEWRULE:
                        list_del_rcu(&nft_trans_rule(trans)->list);
                        break;
@@ -3269,6 +3379,9 @@ 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_NEWCHAIN:
+                       nf_tables_chain_destroy(trans->ctx.chain);
+                       break;
                case NFT_MSG_NEWRULE:
                        nf_tables_rule_destroy(&trans->ctx,
                                               nft_trans_rule(trans));