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Date: Wed, 23 Jun 2021 19:02:58 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org, kuba@...nel.org
Subject: [PATCH net-next 3/6] netfilter: nf_tables: add last expression
Add a new optional expression that tells you when last matching on a
given rule / set element element has happened.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/nf_tables_core.h | 1 +
include/uapi/linux/netfilter/nf_tables.h | 15 ++++
net/netfilter/Makefile | 2 +-
net/netfilter/nf_tables_core.c | 1 +
net/netfilter/nft_last.c | 87 ++++++++++++++++++++++++
5 files changed, 105 insertions(+), 1 deletion(-)
create mode 100644 net/netfilter/nft_last.c
diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h
index 46c8d5bb5d8d..0fa5a6d98a00 100644
--- a/include/net/netfilter/nf_tables_core.h
+++ b/include/net/netfilter/nf_tables_core.h
@@ -16,6 +16,7 @@ extern struct nft_expr_type nft_range_type;
extern struct nft_expr_type nft_meta_type;
extern struct nft_expr_type nft_rt_type;
extern struct nft_expr_type nft_exthdr_type;
+extern struct nft_expr_type nft_last_type;
#ifdef CONFIG_NETWORK_SECMARK
extern struct nft_object_type nft_secmark_obj_type;
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 19715e2679d1..e94d1fa554cb 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1195,6 +1195,21 @@ enum nft_counter_attributes {
};
#define NFTA_COUNTER_MAX (__NFTA_COUNTER_MAX - 1)
+/**
+ * enum nft_last_attributes - nf_tables last expression netlink attributes
+ *
+ * @NFTA_LAST_SET: last update has been set, zero means never updated (NLA_U32)
+ * @NFTA_LAST_MSECS: milliseconds since last update (NLA_U64)
+ */
+enum nft_last_attributes {
+ NFTA_LAST_UNSPEC,
+ NFTA_LAST_SET,
+ 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/Makefile b/net/netfilter/Makefile
index 87112dad1fd4..049890e00a3d 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -74,7 +74,7 @@ obj-$(CONFIG_NF_DUP_NETDEV) += nf_dup_netdev.o
nf_tables-objs := nf_tables_core.o nf_tables_api.o nft_chain_filter.o \
nf_tables_trace.o nft_immediate.o nft_cmp.o nft_range.o \
nft_bitwise.o nft_byteorder.o nft_payload.o nft_lookup.o \
- nft_dynset.o nft_meta.o nft_rt.o nft_exthdr.o \
+ nft_dynset.o nft_meta.o nft_rt.o nft_exthdr.o nft_last.o \
nft_chain_route.o nf_tables_offload.o \
nft_set_hash.o nft_set_bitmap.o nft_set_rbtree.o \
nft_set_pipapo.o
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c
index 7780342e2f2d..866cfba04d6c 100644
--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -268,6 +268,7 @@ static struct nft_expr_type *nft_basic_types[] = {
&nft_meta_type,
&nft_rt_type,
&nft_exthdr_type,
+ &nft_last_type,
};
static struct nft_object_type *nft_basic_objects[] = {
diff --git a/net/netfilter/nft_last.c b/net/netfilter/nft_last.c
new file mode 100644
index 000000000000..913ac45167f2
--- /dev/null
+++ b/net/netfilter/nft_last.c
@@ -0,0 +1,87 @@
+// 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_priv {
+ unsigned long last_jiffies;
+ unsigned int last_set;
+};
+
+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);
+ u64 last_jiffies;
+ int err;
+
+ if (tb[NFTA_LAST_MSECS]) {
+ err = nf_msecs_to_jiffies64(tb[NFTA_LAST_MSECS], &last_jiffies);
+ if (err < 0)
+ return err;
+
+ priv->last_jiffies = jiffies + (unsigned long)last_jiffies;
+ priv->last_set = 1;
+ }
+
+ 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;
+ priv->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);
+ __be64 msecs;
+
+ if (time_before(jiffies, priv->last_jiffies))
+ priv->last_set = 0;
+
+ if (priv->last_set)
+ msecs = nf_jiffies64_to_msecs(jiffies - priv->last_jiffies);
+ else
+ msecs = 0;
+
+ if (nla_put_be32(skb, NFTA_LAST_SET, htonl(priv->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 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,
+};
+
+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,
+};
--
2.30.2
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