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netfilter: nft_last: move stateful fields out of expression data
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In preparation for the rule blob representation.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Pablo Neira Ayuso committed Jan 9, 2022
1 parent 37f319f commit 33a24de
Showing 1 changed file with 51 additions and 18 deletions.
69 changes: 51 additions & 18 deletions net/netfilter/nft_last.c
Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,13 @@
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>

struct nft_last {
unsigned long jiffies;
unsigned int set;
};

struct nft_last_priv {
unsigned long last_jiffies;
unsigned int last_set;
struct nft_last *last;
};

static const struct nla_policy nft_last_policy[NFTA_LAST_MAX + 1] = {
Expand All @@ -22,47 +26,55 @@ static int nft_last_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_last_priv *priv = nft_expr_priv(expr);
struct nft_last *last;
u64 last_jiffies;
u32 last_set = 0;
int err;

if (tb[NFTA_LAST_SET]) {
last_set = ntohl(nla_get_be32(tb[NFTA_LAST_SET]));
if (last_set == 1)
priv->last_set = 1;
}
last = kzalloc(sizeof(*last), GFP_KERNEL);
if (!last)
return -ENOMEM;

if (tb[NFTA_LAST_SET])
last->set = ntohl(nla_get_be32(tb[NFTA_LAST_SET]));

if (last_set && tb[NFTA_LAST_MSECS]) {
if (last->set && tb[NFTA_LAST_MSECS]) {
err = nf_msecs_to_jiffies64(tb[NFTA_LAST_MSECS], &last_jiffies);
if (err < 0)
return err;
goto err;

priv->last_jiffies = jiffies - (unsigned long)last_jiffies;
last->jiffies = jiffies - (unsigned long)last_jiffies;
}
priv->last = last;

return 0;
err:
kfree(last);

return err;
}

static void nft_last_eval(const struct nft_expr *expr,
struct nft_regs *regs, const struct nft_pktinfo *pkt)
{
struct nft_last_priv *priv = nft_expr_priv(expr);
struct nft_last *last = priv->last;

if (READ_ONCE(priv->last_jiffies) != jiffies)
WRITE_ONCE(priv->last_jiffies, jiffies);
if (READ_ONCE(priv->last_set) == 0)
WRITE_ONCE(priv->last_set, 1);
if (READ_ONCE(last->jiffies) != jiffies)
WRITE_ONCE(last->jiffies, jiffies);
if (READ_ONCE(last->set) == 0)
WRITE_ONCE(last->set, 1);
}

static int nft_last_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
struct nft_last_priv *priv = nft_expr_priv(expr);
unsigned long last_jiffies = READ_ONCE(priv->last_jiffies);
u32 last_set = READ_ONCE(priv->last_set);
struct nft_last *last = priv->last;
unsigned long last_jiffies = READ_ONCE(last->jiffies);
u32 last_set = READ_ONCE(last->set);
__be64 msecs;

if (time_before(jiffies, last_jiffies)) {
WRITE_ONCE(priv->last_set, 0);
WRITE_ONCE(last->set, 0);
last_set = 0;
}

Expand All @@ -81,11 +93,32 @@ static int nft_last_dump(struct sk_buff *skb, const struct nft_expr *expr)
return -1;
}

static void nft_last_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
struct nft_last_priv *priv = nft_expr_priv(expr);

kfree(priv->last);
}

static int nft_last_clone(struct nft_expr *dst, const struct nft_expr *src)
{
struct nft_last_priv *priv_dst = nft_expr_priv(dst);

priv_dst->last = kzalloc(sizeof(*priv_dst->last), GFP_ATOMIC);
if (priv_dst->last)
return -ENOMEM;

return 0;
}

static const struct nft_expr_ops nft_last_ops = {
.type = &nft_last_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_last_priv)),
.eval = nft_last_eval,
.init = nft_last_init,
.destroy = nft_last_destroy,
.clone = nft_last_clone,
.dump = nft_last_dump,
};

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