diff options
Diffstat (limited to 'net/netfilter/nft_last.c')
-rw-r--r-- | net/netfilter/nft_last.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/net/netfilter/nft_last.c b/net/netfilter/nft_last.c new file mode 100644 index 000000000..eaa54964c --- /dev/null +++ b/net/netfilter/nft_last.c @@ -0,0 +1,137 @@ +// 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); + struct nft_last_priv *priv_src = nft_expr_priv(src); + + priv_dst->last = kzalloc(sizeof(*priv_dst->last), GFP_ATOMIC); + if (!priv_dst->last) + return -ENOMEM; + + priv_dst->last->set = priv_src->last->set; + priv_dst->last->jiffies = priv_src->last->jiffies; + + 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, +}; |