1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
5 * Development of this code funded by Astaro AG (http://www.astaro.com/)
8 #include <linux/kernel.h>
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/spinlock.h>
12 #include <linux/netlink.h>
13 #include <linux/netfilter.h>
14 #include <linux/netfilter/nf_tables.h>
15 #include <net/netfilter/nf_tables.h>
23 struct nft_limit_priv {
24 struct nft_limit *limit;
32 static inline bool nft_limit_eval(struct nft_limit_priv *priv, u64 cost)
37 spin_lock_bh(&priv->limit->lock);
39 tokens = priv->limit->tokens + now - priv->limit->last;
40 if (tokens > priv->tokens_max)
41 tokens = priv->tokens_max;
43 priv->limit->last = now;
44 delta = tokens - cost;
46 priv->limit->tokens = delta;
47 spin_unlock_bh(&priv->limit->lock);
50 priv->limit->tokens = tokens;
51 spin_unlock_bh(&priv->limit->lock);
55 /* Use same default as in iptables. */
56 #define NFT_LIMIT_PKT_BURST_DEFAULT 5
58 static int nft_limit_init(struct nft_limit_priv *priv,
59 const struct nlattr * const tb[], bool pkts)
63 if (tb[NFTA_LIMIT_RATE] == NULL ||
64 tb[NFTA_LIMIT_UNIT] == NULL)
67 priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
68 unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
69 priv->nsecs = unit * NSEC_PER_SEC;
70 if (priv->rate == 0 || priv->nsecs < unit)
73 if (tb[NFTA_LIMIT_BURST])
74 priv->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST]));
76 if (pkts && priv->burst == 0)
77 priv->burst = NFT_LIMIT_PKT_BURST_DEFAULT;
79 if (priv->rate + priv->burst < priv->rate)
83 tokens = div64_u64(priv->nsecs, priv->rate) * priv->burst;
85 /* The token bucket size limits the number of tokens can be
86 * accumulated. tokens_max specifies the bucket size.
87 * tokens_max = unit * (rate + burst) / rate.
89 tokens = div64_u64(priv->nsecs * (priv->rate + priv->burst),
93 priv->limit = kmalloc(sizeof(*priv->limit), GFP_KERNEL);
97 priv->limit->tokens = tokens;
98 priv->tokens_max = priv->limit->tokens;
100 if (tb[NFTA_LIMIT_FLAGS]) {
101 u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS]));
103 if (flags & NFT_LIMIT_F_INV)
106 priv->limit->last = ktime_get_ns();
107 spin_lock_init(&priv->limit->lock);
112 static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit_priv *priv,
113 enum nft_limit_type type)
115 u32 flags = priv->invert ? NFT_LIMIT_F_INV : 0;
116 u64 secs = div_u64(priv->nsecs, NSEC_PER_SEC);
118 if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate),
120 nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs),
122 nla_put_be32(skb, NFTA_LIMIT_BURST, htonl(priv->burst)) ||
123 nla_put_be32(skb, NFTA_LIMIT_TYPE, htonl(type)) ||
124 nla_put_be32(skb, NFTA_LIMIT_FLAGS, htonl(flags)))
125 goto nla_put_failure;
132 static void nft_limit_destroy(const struct nft_ctx *ctx,
133 const struct nft_limit_priv *priv)
138 static int nft_limit_clone(struct nft_limit_priv *priv_dst,
139 const struct nft_limit_priv *priv_src)
141 priv_dst->tokens_max = priv_src->tokens_max;
142 priv_dst->rate = priv_src->rate;
143 priv_dst->nsecs = priv_src->nsecs;
144 priv_dst->burst = priv_src->burst;
145 priv_dst->invert = priv_src->invert;
147 priv_dst->limit = kmalloc(sizeof(*priv_dst->limit), GFP_ATOMIC);
148 if (!priv_dst->limit)
151 spin_lock_init(&priv_dst->limit->lock);
152 priv_dst->limit->tokens = priv_src->tokens_max;
153 priv_dst->limit->last = ktime_get_ns();
158 struct nft_limit_priv_pkts {
159 struct nft_limit_priv limit;
163 static void nft_limit_pkts_eval(const struct nft_expr *expr,
164 struct nft_regs *regs,
165 const struct nft_pktinfo *pkt)
167 struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
169 if (nft_limit_eval(&priv->limit, priv->cost))
170 regs->verdict.code = NFT_BREAK;
173 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
174 [NFTA_LIMIT_RATE] = { .type = NLA_U64 },
175 [NFTA_LIMIT_UNIT] = { .type = NLA_U64 },
176 [NFTA_LIMIT_BURST] = { .type = NLA_U32 },
177 [NFTA_LIMIT_TYPE] = { .type = NLA_U32 },
178 [NFTA_LIMIT_FLAGS] = { .type = NLA_U32 },
181 static int nft_limit_pkts_init(const struct nft_ctx *ctx,
182 const struct nft_expr *expr,
183 const struct nlattr * const tb[])
185 struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
188 err = nft_limit_init(&priv->limit, tb, true);
192 priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
196 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr)
198 const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
200 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
203 static void nft_limit_pkts_destroy(const struct nft_ctx *ctx,
204 const struct nft_expr *expr)
206 const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr);
208 nft_limit_destroy(ctx, &priv->limit);
211 static int nft_limit_pkts_clone(struct nft_expr *dst, const struct nft_expr *src)
213 struct nft_limit_priv_pkts *priv_dst = nft_expr_priv(dst);
214 struct nft_limit_priv_pkts *priv_src = nft_expr_priv(src);
216 return nft_limit_clone(&priv_dst->limit, &priv_src->limit);
219 static struct nft_expr_type nft_limit_type;
220 static const struct nft_expr_ops nft_limit_pkts_ops = {
221 .type = &nft_limit_type,
222 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)),
223 .eval = nft_limit_pkts_eval,
224 .init = nft_limit_pkts_init,
225 .destroy = nft_limit_pkts_destroy,
226 .clone = nft_limit_pkts_clone,
227 .dump = nft_limit_pkts_dump,
228 .reduce = NFT_REDUCE_READONLY,
231 static void nft_limit_bytes_eval(const struct nft_expr *expr,
232 struct nft_regs *regs,
233 const struct nft_pktinfo *pkt)
235 struct nft_limit_priv *priv = nft_expr_priv(expr);
236 u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);
238 if (nft_limit_eval(priv, cost))
239 regs->verdict.code = NFT_BREAK;
242 static int nft_limit_bytes_init(const struct nft_ctx *ctx,
243 const struct nft_expr *expr,
244 const struct nlattr * const tb[])
246 struct nft_limit_priv *priv = nft_expr_priv(expr);
248 return nft_limit_init(priv, tb, false);
251 static int nft_limit_bytes_dump(struct sk_buff *skb,
252 const struct nft_expr *expr)
254 const struct nft_limit_priv *priv = nft_expr_priv(expr);
256 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
259 static void nft_limit_bytes_destroy(const struct nft_ctx *ctx,
260 const struct nft_expr *expr)
262 const struct nft_limit_priv *priv = nft_expr_priv(expr);
264 nft_limit_destroy(ctx, priv);
267 static int nft_limit_bytes_clone(struct nft_expr *dst, const struct nft_expr *src)
269 struct nft_limit_priv *priv_dst = nft_expr_priv(dst);
270 struct nft_limit_priv *priv_src = nft_expr_priv(src);
272 return nft_limit_clone(priv_dst, priv_src);
275 static const struct nft_expr_ops nft_limit_bytes_ops = {
276 .type = &nft_limit_type,
277 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv)),
278 .eval = nft_limit_bytes_eval,
279 .init = nft_limit_bytes_init,
280 .dump = nft_limit_bytes_dump,
281 .clone = nft_limit_bytes_clone,
282 .destroy = nft_limit_bytes_destroy,
283 .reduce = NFT_REDUCE_READONLY,
286 static const struct nft_expr_ops *
287 nft_limit_select_ops(const struct nft_ctx *ctx,
288 const struct nlattr * const tb[])
290 if (tb[NFTA_LIMIT_TYPE] == NULL)
291 return &nft_limit_pkts_ops;
293 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
295 return &nft_limit_pkts_ops;
296 case NFT_LIMIT_PKT_BYTES:
297 return &nft_limit_bytes_ops;
299 return ERR_PTR(-EOPNOTSUPP);
302 static struct nft_expr_type nft_limit_type __read_mostly = {
304 .select_ops = nft_limit_select_ops,
305 .policy = nft_limit_policy,
306 .maxattr = NFTA_LIMIT_MAX,
307 .flags = NFT_EXPR_STATEFUL,
308 .owner = THIS_MODULE,
311 static void nft_limit_obj_pkts_eval(struct nft_object *obj,
312 struct nft_regs *regs,
313 const struct nft_pktinfo *pkt)
315 struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
317 if (nft_limit_eval(&priv->limit, priv->cost))
318 regs->verdict.code = NFT_BREAK;
321 static int nft_limit_obj_pkts_init(const struct nft_ctx *ctx,
322 const struct nlattr * const tb[],
323 struct nft_object *obj)
325 struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
328 err = nft_limit_init(&priv->limit, tb, true);
332 priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate);
336 static int nft_limit_obj_pkts_dump(struct sk_buff *skb,
337 struct nft_object *obj,
340 const struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
342 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS);
345 static void nft_limit_obj_pkts_destroy(const struct nft_ctx *ctx,
346 struct nft_object *obj)
348 struct nft_limit_priv_pkts *priv = nft_obj_data(obj);
350 nft_limit_destroy(ctx, &priv->limit);
353 static struct nft_object_type nft_limit_obj_type;
354 static const struct nft_object_ops nft_limit_obj_pkts_ops = {
355 .type = &nft_limit_obj_type,
356 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)),
357 .init = nft_limit_obj_pkts_init,
358 .destroy = nft_limit_obj_pkts_destroy,
359 .eval = nft_limit_obj_pkts_eval,
360 .dump = nft_limit_obj_pkts_dump,
363 static void nft_limit_obj_bytes_eval(struct nft_object *obj,
364 struct nft_regs *regs,
365 const struct nft_pktinfo *pkt)
367 struct nft_limit_priv *priv = nft_obj_data(obj);
368 u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate);
370 if (nft_limit_eval(priv, cost))
371 regs->verdict.code = NFT_BREAK;
374 static int nft_limit_obj_bytes_init(const struct nft_ctx *ctx,
375 const struct nlattr * const tb[],
376 struct nft_object *obj)
378 struct nft_limit_priv *priv = nft_obj_data(obj);
380 return nft_limit_init(priv, tb, false);
383 static int nft_limit_obj_bytes_dump(struct sk_buff *skb,
384 struct nft_object *obj,
387 const struct nft_limit_priv *priv = nft_obj_data(obj);
389 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES);
392 static void nft_limit_obj_bytes_destroy(const struct nft_ctx *ctx,
393 struct nft_object *obj)
395 struct nft_limit_priv *priv = nft_obj_data(obj);
397 nft_limit_destroy(ctx, priv);
400 static struct nft_object_type nft_limit_obj_type;
401 static const struct nft_object_ops nft_limit_obj_bytes_ops = {
402 .type = &nft_limit_obj_type,
403 .size = sizeof(struct nft_limit_priv),
404 .init = nft_limit_obj_bytes_init,
405 .destroy = nft_limit_obj_bytes_destroy,
406 .eval = nft_limit_obj_bytes_eval,
407 .dump = nft_limit_obj_bytes_dump,
410 static const struct nft_object_ops *
411 nft_limit_obj_select_ops(const struct nft_ctx *ctx,
412 const struct nlattr * const tb[])
414 if (!tb[NFTA_LIMIT_TYPE])
415 return &nft_limit_obj_pkts_ops;
417 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) {
419 return &nft_limit_obj_pkts_ops;
420 case NFT_LIMIT_PKT_BYTES:
421 return &nft_limit_obj_bytes_ops;
423 return ERR_PTR(-EOPNOTSUPP);
426 static struct nft_object_type nft_limit_obj_type __read_mostly = {
427 .select_ops = nft_limit_obj_select_ops,
428 .type = NFT_OBJECT_LIMIT,
429 .maxattr = NFTA_LIMIT_MAX,
430 .policy = nft_limit_policy,
431 .owner = THIS_MODULE,
434 static int __init nft_limit_module_init(void)
438 err = nft_register_obj(&nft_limit_obj_type);
442 err = nft_register_expr(&nft_limit_type);
448 nft_unregister_obj(&nft_limit_obj_type);
452 static void __exit nft_limit_module_exit(void)
454 nft_unregister_expr(&nft_limit_type);
455 nft_unregister_obj(&nft_limit_obj_type);
458 module_init(nft_limit_module_init);
459 module_exit(nft_limit_module_exit);
461 MODULE_LICENSE("GPL");
462 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
463 MODULE_ALIAS_NFT_EXPR("limit");
464 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_LIMIT);
465 MODULE_DESCRIPTION("nftables limit expression support");