blob: 145dc62c62472605e9f99c6e69f240e4c66774e9 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
struct nft_limit {
spinlock_t lock;
u64 last;
u64 tokens;
};
struct nft_limit_priv {
struct nft_limit *limit;
u64 tokens_max;
u64 rate;
u64 nsecs;
u32 burst;
bool invert;
};
static inline bool nft_limit_eval(struct nft_limit_priv *priv, u64 cost)
{
u64 now, tokens;
s64 delta;
spin_lock_bh(&priv->limit->lock);
now = ktime_get_ns();
tokens = priv->limit->tokens + now - priv->limit->last;
if (tokens > priv->tokens_max)
tokens = priv->tokens_max;
priv->limit->last = now;
delta = tokens - cost;
if (delta >= 0) {
priv->limit->tokens = delta;
spin_unlock_bh(&priv->limit->lock);
return priv->invert;
}
priv->limit->tokens = tokens;
spin_unlock_bh(&priv->limit->lock);
return !priv->invert;
}
/* Use same default as in iptables. */
#define NFT_LIMIT_PKT_BURST_DEFAULT 5
static int nft_limit_init(struct nft_limit_priv *priv,
const struct nlattr * const tb[], bool pkts)
{
u64 unit, tokens;
if (tb[NFTA_LIMIT_RATE] == NULL ||
tb[NFTA_LIMIT_UNIT] == NULL)
return -EINVAL;
priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
priv->nsecs = unit * NSEC_PER_SEC;
if (priv->rate == 0 || priv->nsecs < unit)
return -EOVERFLOW;
if (tb[NFTA_LIMIT_BURST])
priv->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST]));
if (pkts && priv->burst == 0)
priv->burst = NFT_LIMIT_PKT_BURST_DEFAULT;
if (priv->rate + priv->burst < priv->rate)
return -EOVERFLOW;
if (pkts) {
tokens = div64_u64(priv->nsecs, priv->rate) * priv->burst;
} else {
/* The token bucket size limits the number of tokens can be
* accumulated. tokens_max specifies the bucket size.
* tokens_max = unit * (rate + burst) / rate.
*/
tokens = div64_u64(priv->nsecs * (priv->rate + priv->burst),
priv->rate);
}
priv->limit = kmalloc(sizeof(*priv->limit), GFP_KERNEL_ACCOUNT);
if (!priv->limit)
return -ENOMEM;
priv->limit->tokens = tokens;
priv->tokens_max = priv->limit->tokens;
if (tb[NFTA_LIMIT_FLAGS]) {
u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS]));
if (flags & NFT_LIMIT_F_INV)
priv->invert = true;
}
priv->limit->last = ktime_get_ns();
spin_lock_init(&priv->limit->lock);
return 0;
}
static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit_priv *priv,
enum nft_limit_type type)
{
u32 flags = priv->invert ? NFT_LIMIT_F_INV : 0;
u64 secs = div_u64(priv->nsecs, NSEC_PER_SEC);
if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate),
NFTA_LIMIT_PAD) ||
nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs),
NFTA_LIMIT_PAD) ||
nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(priv->burst)) ||
nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type)) ||
nla_put_be32(skb, NFTA_LIMIT_FLAGS, htonl(flags)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static void nft_limit_destroy(const struct nft_ctx *ctx,
const struct nft_limit_priv *priv)
{
kfree(priv->limit);
}
static int nft_limit_clone(struct nft_limit_priv *priv_dst,
const struct nft_limit_priv *priv_src)
{
priv_dst->tokens_max = priv_src->tokens_max;
priv_dst->rate = priv_src->rate;
priv_dst->nsecs = priv_src->nsecs;
priv_dst->burst = priv_src->burst;
priv_dst->invert = priv_src->invert;
priv_dst->limit = kmalloc(sizeof(*priv_dst->limit), GFP_ATOMIC);
if (!priv_dst->limit)
return -ENOMEM;
spin_lock_init(&priv_dst->limit->lock);
priv_dst->limit->tokens = priv_src->tokens_max;
priv_dst->limit->last = ktime_get_ns();
return 0;
}
struct nft_limit_priv_pkts {
struct nft_limit_priv limit;
u64 cost;
};
static void nft_limit_pkts_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
if (nft_limit_eval(&priv->limit, priv->cost))
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
[NFTA_LIMIT_RATE] = { .type = NLA_U64 },
[NFTA_LIMIT_UNIT] = { .type = NLA_U64 },
[NFTA_LIMIT_BURST] = { .type = NLA_U32 },
[NFTA_LIMIT_TYPE] = { .type = NLA_U32 },
[NFTA_LIMIT_FLAGS] = { .type = NLA_U32 },
};
static int nft_limit_pkts_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
int err;
err = nft_limit_init(&priv->limit, tb, true);
if (err < 0)
return err;
priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
return 0;
}
static int nft_limit_pkts_dump(struct sk_buff *skb,
const struct nft_expr *expr, bool reset)
{
const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
}
static void nft_limit_pkts_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
nft_limit_destroy(ctx, &priv->limit);
}
static int nft_limit_pkts_clone(struct nft_expr *dst, const struct nft_expr *src)
{
struct nft_limit_priv_pkts *priv_dst = nft_expr_priv(dst);
struct nft_limit_priv_pkts *priv_src = nft_expr_priv(src);
priv_dst->cost = priv_src->cost;
return nft_limit_clone(&priv_dst->limit, &priv_src->limit);
}
static struct nft_expr_type nft_limit_type;
static const struct nft_expr_ops nft_limit_pkts_ops = {
.type = &nft_limit_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)),
.eval = nft_limit_pkts_eval,
.init = nft_limit_pkts_init,
.destroy = nft_limit_pkts_destroy,
.clone = nft_limit_pkts_clone,
.dump = nft_limit_pkts_dump,
.reduce = NFT_REDUCE_READONLY,
};
static void nft_limit_bytes_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_limit_priv *priv = nft_expr_priv(expr);
u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);
if (nft_limit_eval(priv, cost))
regs->verdict.code = NFT_BREAK;
}
static int nft_limit_bytes_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_limit_priv *priv = nft_expr_priv(expr);
return nft_limit_init(priv, tb, false);
}
static int nft_limit_bytes_dump(struct sk_buff *skb,
const struct nft_expr *expr, bool reset)
{
const struct nft_limit_priv *priv = nft_expr_priv(expr);
return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
}
static void nft_limit_bytes_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
const struct nft_limit_priv *priv = nft_expr_priv(expr);
nft_limit_destroy(ctx, priv);
}
static int nft_limit_bytes_clone(struct nft_expr *dst, const struct nft_expr *src)
{
struct nft_limit_priv *priv_dst = nft_expr_priv(dst);
struct nft_limit_priv *priv_src = nft_expr_priv(src);
return nft_limit_clone(priv_dst, priv_src);
}
static const struct nft_expr_ops nft_limit_bytes_ops = {
.type = &nft_limit_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv)),
.eval = nft_limit_bytes_eval,
.init = nft_limit_bytes_init,
.dump = nft_limit_bytes_dump,
.clone = nft_limit_bytes_clone,
.destroy = nft_limit_bytes_destroy,
.reduce = NFT_REDUCE_READONLY,
};
static const struct nft_expr_ops *
nft_limit_select_ops(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
if (tb[NFTA_LIMIT_TYPE] == NULL)
return &nft_limit_pkts_ops;
switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
case NFT_LIMIT_PKTS:
return &nft_limit_pkts_ops;
case NFT_LIMIT_PKT_BYTES:
return &nft_limit_bytes_ops;
}
return ERR_PTR(-EOPNOTSUPP);
}
static struct nft_expr_type nft_limit_type __read_mostly = {
.name = "limit",
.select_ops = nft_limit_select_ops,
.policy = nft_limit_policy,
.maxattr = NFTA_LIMIT_MAX,
.flags = NFT_EXPR_STATEFUL,
.owner = THIS_MODULE,
};
static void nft_limit_obj_pkts_eval(struct nft_object *obj,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
if (nft_limit_eval(&priv->limit, priv->cost))
regs->verdict.code = NFT_BREAK;
}
static int nft_limit_obj_pkts_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[],
struct nft_object *obj)
{
struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
int err;
err = nft_limit_init(&priv->limit, tb, true);
if (err < 0)
return err;
priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
return 0;
}
static int nft_limit_obj_pkts_dump(struct sk_buff *skb,
struct nft_object *obj,
bool reset)
{
const struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
}
static void nft_limit_obj_pkts_destroy(const struct nft_ctx *ctx,
struct nft_object *obj)
{
struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
nft_limit_destroy(ctx, &priv->limit);
}
static struct nft_object_type nft_limit_obj_type;
static const struct nft_object_ops nft_limit_obj_pkts_ops = {
.type = &nft_limit_obj_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)),
.init = nft_limit_obj_pkts_init,
.destroy = nft_limit_obj_pkts_destroy,
.eval = nft_limit_obj_pkts_eval,
.dump = nft_limit_obj_pkts_dump,
};
static void nft_limit_obj_bytes_eval(struct nft_object *obj,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_limit_priv *priv = nft_obj_data(obj);
u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);
if (nft_limit_eval(priv, cost))
regs->verdict.code = NFT_BREAK;
}
static int nft_limit_obj_bytes_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[],
struct nft_object *obj)
{
struct nft_limit_priv *priv = nft_obj_data(obj);
return nft_limit_init(priv, tb, false);
}
static int nft_limit_obj_bytes_dump(struct sk_buff *skb,
struct nft_object *obj,
bool reset)
{
const struct nft_limit_priv *priv = nft_obj_data(obj);
return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
}
static void nft_limit_obj_bytes_destroy(const struct nft_ctx *ctx,
struct nft_object *obj)
{
struct nft_limit_priv *priv = nft_obj_data(obj);
nft_limit_destroy(ctx, priv);
}
static struct nft_object_type nft_limit_obj_type;
static const struct nft_object_ops nft_limit_obj_bytes_ops = {
.type = &nft_limit_obj_type,
.size = sizeof(struct nft_limit_priv),
.init = nft_limit_obj_bytes_init,
.destroy = nft_limit_obj_bytes_destroy,
.eval = nft_limit_obj_bytes_eval,
.dump = nft_limit_obj_bytes_dump,
};
static const struct nft_object_ops *
nft_limit_obj_select_ops(const struct nft_ctx *ctx,
const struct nlattr * const tb[])
{
if (!tb[NFTA_LIMIT_TYPE])
return &nft_limit_obj_pkts_ops;
switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
case NFT_LIMIT_PKTS:
return &nft_limit_obj_pkts_ops;
case NFT_LIMIT_PKT_BYTES:
return &nft_limit_obj_bytes_ops;
}
return ERR_PTR(-EOPNOTSUPP);
}
static struct nft_object_type nft_limit_obj_type __read_mostly = {
.select_ops = nft_limit_obj_select_ops,
.type = NFT_OBJECT_LIMIT,
.maxattr = NFTA_LIMIT_MAX,
.policy = nft_limit_policy,
.owner = THIS_MODULE,
};
static int __init nft_limit_module_init(void)
{
int err;
err = nft_register_obj(&nft_limit_obj_type);
if (err < 0)
return err;
err = nft_register_expr(&nft_limit_type);
if (err < 0)
goto err1;
return 0;
err1:
nft_unregister_obj(&nft_limit_obj_type);
return err;
}
static void __exit nft_limit_module_exit(void)
{
nft_unregister_expr(&nft_limit_type);
nft_unregister_obj(&nft_limit_obj_type);
}
module_init(nft_limit_module_init);
module_exit(nft_limit_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("limit");
MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_LIMIT);
MODULE_DESCRIPTION("nftables limit expression support");