| // 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, rate_with_burst; |
| bool invert = false; |
| |
| 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])); |
| if (priv->rate == 0) |
| return -EINVAL; |
| |
| unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT])); |
| if (check_mul_overflow(unit, NSEC_PER_SEC, &priv->nsecs)) |
| 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 (check_add_overflow(priv->rate, priv->burst, &rate_with_burst)) |
| return -EOVERFLOW; |
| |
| if (pkts) { |
| u64 tmp = div64_u64(priv->nsecs, priv->rate); |
| |
| if (check_mul_overflow(tmp, priv->burst, &tokens)) |
| return -EOVERFLOW; |
| } else { |
| u64 tmp; |
| |
| /* The token bucket size limits the number of tokens can be |
| * accumulated. tokens_max specifies the bucket size. |
| * tokens_max = unit * (rate + burst) / rate. |
| */ |
| if (check_mul_overflow(priv->nsecs, rate_with_burst, &tmp)) |
| return -EOVERFLOW; |
| |
| tokens = div64_u64(tmp, priv->rate); |
| } |
| |
| if (tb[NFTA_LIMIT_FLAGS]) { |
| u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS])); |
| |
| if (flags & ~NFT_LIMIT_F_INV) |
| return -EOPNOTSUPP; |
| |
| if (flags & NFT_LIMIT_F_INV) |
| invert = true; |
| } |
| |
| priv->limit = kmalloc(sizeof(*priv->limit), GFP_KERNEL_ACCOUNT); |
| if (!priv->limit) |
| return -ENOMEM; |
| |
| priv->limit->tokens = tokens; |
| priv->tokens_max = priv->limit->tokens; |
| priv->invert = invert; |
| 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) |
| { |
| 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, |
| }; |
| |
| 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) |
| { |
| 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, |
| }; |
| |
| 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"); |