Add a new optional expression that allows you to know when last match on
a given rule / set element.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 13 ++++
net/netfilter/Kconfig | 6 ++
net/netfilter/Makefile | 1 +
net/netfilter/nft_last.c | 94 ++++++++++++++++++++++++
4 files changed, 114 insertions(+)
create mode 100644 net/netfilter/nft_last.c
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 19715e2679d1..1c5814e3b2b2 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1195,6 +1195,19 @@ enum nft_counter_attributes {
};
#define NFTA_COUNTER_MAX (__NFTA_COUNTER_MAX - 1)
+/**
+ * enum nft_last_attributes - nf_tables last expression netlink attributes
+ *
+ * @NFTA_LAST_MSECS: number of bytes (NLA_U64)
+ */
+enum nft_last_attributes {
+ NFTA_LAST_UNSPEC,
+ NFTA_LAST_MSECS,
+ NFTA_LAST_PAD,
+ __NFTA_LAST_MAX
+};
+#define NFTA_LAST_MAX (__NFTA_LAST_MAX - 1)
+
/**
* enum nft_log_attributes - nf_tables log expression netlink attributes
*
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 172d74560632..cf113cbfb69e 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -509,6 +509,12 @@ config NFT_CONNLIMIT
This option adds the "connlimit" expression that you can use to
ratelimit rule matchings per connections.
+config NFT_LAST
+ tristate "Netfilter nf_tables last module"
+ help
+ This option adds the "last" expression that you can use to know
+ when this rule has matched last time.
+
config NFT_LOG
tristate "Netfilter nf_tables log module"
help
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index e80e010354b1..60204c6542e7 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_NFT_REJECT_INET) += nft_reject_inet.o
obj-$(CONFIG_NFT_REJECT_NETDEV) += nft_reject_netdev.o
obj-$(CONFIG_NFT_TUNNEL) += nft_tunnel.o
obj-$(CONFIG_NFT_COUNTER) += nft_counter.o
+obj-$(CONFIG_NFT_LAST) += nft_last.o
obj-$(CONFIG_NFT_LOG) += nft_log.o
obj-$(CONFIG_NFT_MASQ) += nft_masq.o
obj-$(CONFIG_NFT_REDIR) += nft_redir.o
diff --git a/net/netfilter/nft_last.c b/net/netfilter/nft_last.c
new file mode 100644
index 000000000000..14b3aa27d4c4
--- /dev/null
+++ b/net/netfilter/nft_last.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/seqlock.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+
+struct nft_last_priv {
+ unsigned long last_jiffies;
+};
+
+static const struct nla_policy nft_last_policy[NFTA_LAST_MAX + 1] = {
+ [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);
+ u64 last;
+ int err;
+
+ if (tb[NFTA_LAST_MSECS]) {
+ err = nf_msecs_to_jiffies64(tb[NFTA_LAST_MSECS], &last);
+ if (err < 0)
+ return err;
+
+ priv->last_jiffies = (unsigned long)last;
+ }
+
+ return 0;
+}
+
+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);
+
+ priv->last_jiffies = jiffies;
+}
+
+static int nft_last_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+ struct nft_last_priv *priv = nft_expr_priv(expr);
+
+ if (nla_put_be64(skb, NFTA_LAST_MSECS,
+ nf_jiffies64_to_msecs(priv->last_jiffies),
+ NFTA_LAST_PAD))
+ goto nla_put_failure;
+
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+static struct nft_expr_type nft_last_type;
+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,
+ .dump = nft_last_dump,
+};
+
+static 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,
+};
+
+static int __init nft_last_module_init(void)
+{
+ return nft_register_expr(&nft_last_type);
+}
+
+static void __exit nft_last_module_exit(void)
+{
+ nft_unregister_expr(&nft_last_type);
+}
+
+module_init(nft_last_module_init);
+module_exit(nft_last_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>");
+MODULE_ALIAS_NFT_EXPR("last");
+MODULE_DESCRIPTION("nftables last expression support");
--
2.20.1
