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> --- v2: no Kconfig, make it built-in per Florian. fix incorrect documentation remove #include seqlock.h include/uapi/linux/netfilter/nf_tables.h | 13 ++++ net/netfilter/Makefile | 2 +- net/netfilter/nft_last.c | 93 ++++++++++++++++++++++++ 3 files changed, 107 insertions(+), 1 deletion(-) 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..5beb5a807687 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: milliseconds since last update (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/Makefile b/net/netfilter/Makefile index e80e010354b1..f321ee469ca4 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -73,7 +73,7 @@ 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/nft_last.c b/net/netfilter/nft_last.c new file mode 100644 index 000000000000..2ab4b030dcf9 --- /dev/null +++ b/net/netfilter/nft_last.c @@ -0,0 +1,93 @@ +// 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.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"); -- 2.30.2