netfilter: nf_tables: atomic dump and reset for stateful objects

This patch adds a new NFT_MSG_GETOBJ_RESET command perform an atomic
dump-and-reset of the stateful object. This also comes with add support
for atomic dump and reset for counter and quota objects.

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 903cd618f50e0209422c13b09406eefca8ede4dd..6f7d6a1dc09c824510083cac13fb90d41c9ba0b0 100644 (file)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -997,7 +997,8 @@ struct nft_object_type {
                                                struct nft_object *obj);
        void                            (*destroy)(struct nft_object *obj);
        int                             (*dump)(struct sk_buff *skb,
-                                               const struct nft_object *obj);
+                                               struct nft_object *obj,
+                                               bool reset);
 };
 
 int nft_register_obj(struct nft_object_type *obj_type);

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 3d47582caa8007335adce315b7c1ad4dd1b65c50..399eac1eee911abaa5f85e364c19fb2f5f93d7e4 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -89,6 +89,7 @@ enum nft_verdicts {
  * @NFT_MSG_NEWOBJ: create a stateful object (enum nft_obj_attributes)
  * @NFT_MSG_GETOBJ: get a stateful object (enum nft_obj_attributes)
  * @NFT_MSG_DELOBJ: delete a stateful object (enum nft_obj_attributes)
+ * @NFT_MSG_GETOBJ_RESET: get and reset a stateful object (enum nft_obj_attributes)
  */
 enum nf_tables_msg_types {
        NFT_MSG_NEWTABLE,
@@ -112,6 +113,7 @@ enum nf_tables_msg_types {
        NFT_MSG_NEWOBJ,
        NFT_MSG_GETOBJ,
        NFT_MSG_DELOBJ,
+       NFT_MSG_GETOBJ_RESET,
        NFT_MSG_MAX,
 };
 

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 2ae717c5dcb8ec8758a3f22e93e494922bf0b27b..bfc015af366a72476b2e3d45a9bc8bb61b3afed8 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3972,14 +3972,14 @@ err1:
 }
 
 static int nft_object_dump(struct sk_buff *skb, unsigned int attr,
-                          const struct nft_object *obj)
+                          struct nft_object *obj, bool reset)
 {
        struct nlattr *nest;
 
        nest = nla_nest_start(skb, attr);
        if (!nest)
                goto nla_put_failure;
-       if (obj->type->dump(skb, obj) < 0)
+       if (obj->type->dump(skb, obj, reset) < 0)
                goto nla_put_failure;
        nla_nest_end(skb, nest);
        return 0;
@@ -4096,7 +4096,7 @@ err1:
 static int nf_tables_fill_obj_info(struct sk_buff *skb, struct net *net,
                                   u32 portid, u32 seq, int event, u32 flags,
                                   int family, const struct nft_table *table,
-                                  const struct nft_object *obj)
+                                  struct nft_object *obj, bool reset)
 {
        struct nfgenmsg *nfmsg;
        struct nlmsghdr *nlh;
@@ -4115,7 +4115,7 @@ static int nf_tables_fill_obj_info(struct sk_buff *skb, struct net *net,
            nla_put_string(skb, NFTA_OBJ_NAME, obj->name) ||
            nla_put_be32(skb, NFTA_OBJ_TYPE, htonl(obj->type->type)) ||
            nla_put_be32(skb, NFTA_OBJ_USE, htonl(obj->use)) ||
-           nft_object_dump(skb, NFTA_OBJ_DATA, obj))
+           nft_object_dump(skb, NFTA_OBJ_DATA, obj, reset))
                goto nla_put_failure;
 
        nlmsg_end(skb, nlh);
@@ -4131,10 +4131,14 @@ static int nf_tables_dump_obj(struct sk_buff *skb, struct netlink_callback *cb)
        const struct nfgenmsg *nfmsg = nlmsg_data(cb->nlh);
        const struct nft_af_info *afi;
        const struct nft_table *table;
-       const struct nft_object *obj;
        unsigned int idx = 0, s_idx = cb->args[0];
        struct net *net = sock_net(skb->sk);
        int family = nfmsg->nfgen_family;
+       struct nft_object *obj;
+       bool reset = false;
+
+       if (NFNL_MSG_TYPE(cb->nlh->nlmsg_type) == NFT_MSG_GETOBJ_RESET)
+               reset = true;
 
        rcu_read_lock();
        cb->seq = net->nft.base_seq;
@@ -4156,7 +4160,7 @@ static int nf_tables_dump_obj(struct sk_buff *skb, struct netlink_callback *cb)
                                                            cb->nlh->nlmsg_seq,
                                                            NFT_MSG_NEWOBJ,
                                                            NLM_F_MULTI | NLM_F_APPEND,
-                                                           afi->family, table, obj) < 0)
+                                                           afi->family, table, obj, reset) < 0)
                                        goto done;
 
                                nl_dump_check_consistent(cb, nlmsg_hdr(skb));
@@ -4183,6 +4187,7 @@ static int nf_tables_getobj(struct net *net, struct sock *nlsk,
        const struct nft_table *table;
        struct nft_object *obj;
        struct sk_buff *skb2;
+       bool reset = false;
        u32 objtype;
        int err;
 
@@ -4214,9 +4219,12 @@ static int nf_tables_getobj(struct net *net, struct sock *nlsk,
        if (!skb2)
                return -ENOMEM;
 
+       if (NFNL_MSG_TYPE(nlh->nlmsg_type) == NFT_MSG_GETOBJ_RESET)
+               reset = true;
+
        err = nf_tables_fill_obj_info(skb2, net, NETLINK_CB(skb).portid,
                                      nlh->nlmsg_seq, NFT_MSG_NEWOBJ, 0,
-                                     family, table, obj);
+                                     family, table, obj, reset);
        if (err < 0)
                goto err;
 
@@ -4291,7 +4299,7 @@ static int nf_tables_obj_notify(const struct nft_ctx *ctx,
 
        err = nf_tables_fill_obj_info(skb, ctx->net, ctx->portid, ctx->seq,
                                      event, 0, ctx->afi->family, ctx->table,
-                                     obj);
+                                     obj, false);
        if (err < 0) {
                kfree_skb(skb);
                goto err;
@@ -4482,6 +4490,11 @@ static const struct nfnl_callback nf_tables_cb[NFT_MSG_MAX] = {
                .attr_count     = NFTA_OBJ_MAX,
                .policy         = nft_obj_policy,
        },
+       [NFT_MSG_GETOBJ_RESET] = {
+               .call           = nf_tables_getobj,
+               .attr_count     = NFTA_OBJ_MAX,
+               .policy         = nft_obj_policy,
+       },
 };
 
 static void nft_chain_commit_update(struct nft_trans *trans)

diff --git a/net/netfilter/nft_counter.c b/net/netfilter/nft_counter.c
index 6f3dd429f865c56f61d2e65201d6c90b61c7ef75..f6a02c5071c2aeafca7635da3282a809aa04d6ab 100644 (file)
--- a/net/netfilter/nft_counter.c
+++ b/net/netfilter/nft_counter.c
@@ -100,10 +100,10 @@ static void nft_counter_obj_destroy(struct nft_object *obj)
        nft_counter_do_destroy(priv);
 }
 
-static void nft_counter_fetch(const struct nft_counter_percpu __percpu *counter,
+static void nft_counter_fetch(struct nft_counter_percpu __percpu *counter,
                              struct nft_counter *total)
 {
-       const struct nft_counter_percpu *cpu_stats;
+       struct nft_counter_percpu *cpu_stats;
        u64 bytes, packets;
        unsigned int seq;
        int cpu;
@@ -122,12 +122,52 @@ static void nft_counter_fetch(const struct nft_counter_percpu __percpu *counter,
        }
 }
 
+static u64 __nft_counter_reset(u64 *counter)
+{
+       u64 ret, old;
+
+       do {
+               old = *counter;
+               ret = cmpxchg64(counter, old, 0);
+       } while (ret != old);
+
+       return ret;
+}
+
+static void nft_counter_reset(struct nft_counter_percpu __percpu *counter,
+                             struct nft_counter *total)
+{
+       struct nft_counter_percpu *cpu_stats;
+       u64 bytes, packets;
+       unsigned int seq;
+       int cpu;
+
+       memset(total, 0, sizeof(*total));
+       for_each_possible_cpu(cpu) {
+               bytes = packets = 0;
+
+               cpu_stats = per_cpu_ptr(counter, cpu);
+               do {
+                       seq     = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
+                       packets += __nft_counter_reset(&cpu_stats->counter.packets);
+                       bytes   += __nft_counter_reset(&cpu_stats->counter.bytes);
+               } while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, seq));
+
+               total->packets += packets;
+               total->bytes += bytes;
+       }
+}
+
 static int nft_counter_do_dump(struct sk_buff *skb,
-                              const struct nft_counter_percpu_priv *priv)
+                              const struct nft_counter_percpu_priv *priv,
+                              bool reset)
 {
        struct nft_counter total;
 
-       nft_counter_fetch(priv->counter, &total);
+       if (reset)
+               nft_counter_reset(priv->counter, &total);
+       else
+               nft_counter_fetch(priv->counter, &total);
 
        if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
                         NFTA_COUNTER_PAD) ||
@@ -141,11 +181,11 @@ nla_put_failure:
 }
 
 static int nft_counter_obj_dump(struct sk_buff *skb,
-                               const struct nft_object *obj)
+                               struct nft_object *obj, bool reset)
 {
-       const struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
+       struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 
-       return nft_counter_do_dump(skb, priv);
+       return nft_counter_do_dump(skb, priv, reset);
 }
 
 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
@@ -178,7 +218,7 @@ static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
        const struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 
-       return nft_counter_do_dump(skb, priv);
+       return nft_counter_do_dump(skb, priv, false);
 }
 
 static int nft_counter_init(const struct nft_ctx *ctx,

diff --git a/net/netfilter/nft_quota.c b/net/netfilter/nft_quota.c
index 0d344209803ac162741b0d2042e17d94f8f97d13..5d25f57497cbd1d00d455a86f58902ba6c02b7ef 100644 (file)
--- a/net/netfilter/nft_quota.c
+++ b/net/netfilter/nft_quota.c
@@ -83,12 +83,17 @@ static int nft_quota_obj_init(const struct nlattr * const tb[],
        return nft_quota_do_init(tb, priv);
 }
 
-static int nft_quota_do_dump(struct sk_buff *skb, const struct nft_quota *priv)
+static int nft_quota_do_dump(struct sk_buff *skb, struct nft_quota *priv,
+                            bool reset)
 {
        u32 flags = priv->invert ? NFT_QUOTA_F_INV : 0;
        u64 consumed;
 
-       consumed = atomic64_read(&priv->consumed);
+       if (reset)
+               consumed = atomic64_xchg(&priv->consumed, 0);
+       else
+               consumed = atomic64_read(&priv->consumed);
+
        /* Since we inconditionally increment consumed quota for each packet
         * that we see, don't go over the quota boundary in what we send to
         * userspace.
@@ -108,11 +113,12 @@ nla_put_failure:
        return -1;
 }
 
-static int nft_quota_obj_dump(struct sk_buff *skb, const struct nft_object *obj)
+static int nft_quota_obj_dump(struct sk_buff *skb, struct nft_object *obj,
+                             bool reset)
 {
        struct nft_quota *priv = nft_obj_data(obj);
 
-       return nft_quota_do_dump(skb, priv);
+       return nft_quota_do_dump(skb, priv, reset);
 }
 
 static struct nft_object_type nft_quota_obj __read_mostly = {
@@ -146,9 +152,9 @@ static int nft_quota_init(const struct nft_ctx *ctx,
 
 static int nft_quota_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
-       const struct nft_quota *priv = nft_expr_priv(expr);
+       struct nft_quota *priv = nft_expr_priv(expr);
 
-       return nft_quota_do_dump(skb, priv);
+       return nft_quota_do_dump(skb, priv, false);
 }
 
 static struct nft_expr_type nft_quota_type;