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netfilter: nf_tables: atomic dump and reset for stateful objects
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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>
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Pablo Neira Ayuso committed Dec 7, 2016
1 parent 795595f commit 43da04a
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Showing 5 changed files with 85 additions and 23 deletions.
3 changes: 2 additions & 1 deletion include/net/netfilter/nf_tables.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
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2 changes: 2 additions & 0 deletions include/uapi/linux/netfilter/nf_tables.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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,
};

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29 changes: 21 additions & 8 deletions net/netfilter/nf_tables_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3972,14 +3972,14 @@ static struct nft_object *nft_obj_init(const struct nft_object_type *type,
}

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;
Expand Down Expand Up @@ -4096,7 +4096,7 @@ static int nf_tables_newobj(struct net *net, struct sock *nlsk,
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;
Expand All @@ -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);
Expand All @@ -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;
Expand All @@ -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));
Expand All @@ -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;

Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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)
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56 changes: 48 additions & 8 deletions net/netfilter/nft_counter.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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) ||
Expand All @@ -141,11 +181,11 @@ static int nft_counter_do_dump(struct sk_buff *skb,
}

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] = {
Expand Down Expand Up @@ -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,
Expand Down
18 changes: 12 additions & 6 deletions net/netfilter/nft_quota.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -108,11 +113,12 @@ static int nft_quota_do_dump(struct sk_buff *skb, const struct nft_quota *priv)
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 = {
Expand Down Expand Up @@ -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;
Expand Down

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