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