1 files changed, 133 insertions, 0 deletions
diff --git a/net/netfilter/nft_last.c b/net/netfilter/nft_last.c
new file mode 100644
index 000000000000..bb15a55dad5c
--- /dev/null
+++ b/net/netfilter/nft_last.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#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 {
+	struct nft_last	*last;
+};
+
+static const struct nla_policy nft_last_policy[NFTA_LAST_MAX + 1] = {
+	[NFTA_LAST_SET] = { .type = NLA_U32 },
+	[NFTA_LAST_MSECS] = { .type = NLA_U64 },
+};
+
+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;
+	int err;
+
+	last = kzalloc(sizeof(*last), GFP_KERNEL_ACCOUNT);
+	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]) {
+		err = nf_msecs_to_jiffies64(tb[NFTA_LAST_MSECS], &last_jiffies);
+		if (err < 0)
+			goto err;
+
+		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(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);
+	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(last->set, 0);
+		last_set = 0;
+	}
+
+	if (last_set)
+		msecs = nf_jiffies64_to_msecs(jiffies - last_jiffies);
+	else
+		msecs = 0;
+
+	if (nla_put_be32(skb, NFTA_LAST_SET, htonl(last_set)) ||
+	    nla_put_be64(skb, NFTA_LAST_MSECS, msecs, NFTA_LAST_PAD))
+		goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	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,
+	.reduce		= NFT_REDUCE_READONLY,
+};
+
+struct nft_expr_type nft_last_type __read_mostly = {
+	.name		= "last",
+	.ops		= &nft_last_ops,
+	.policy		= nft_last_policy,
+	.maxattr	= NFTA_LAST_MAX,
+	.flags		= NFT_EXPR_STATEFUL,
+	.owner		= THIS_MODULE,
+};