1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> 4 * 5 * Development of this code funded by Astaro AG (http://www.astaro.com/) 6 */ 7 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> 16 17 struct nft_limit { 18 spinlock_t lock; 19 u64 last; 20 u64 tokens; 21 }; 22 23 struct nft_limit_priv { 24 struct nft_limit *limit; 25 u64 tokens_max; 26 u64 rate; 27 u64 nsecs; 28 u32 burst; 29 bool invert; 30 }; 31 32 static inline bool nft_limit_eval(struct nft_limit_priv *priv, u64 cost) 33 { 34 u64 now, tokens; 35 s64 delta; 36 37 spin_lock_bh(&priv->limit->lock); 38 now = ktime_get_ns(); 39 tokens = priv->limit->tokens + now - priv->limit->last; 40 if (tokens > priv->tokens_max) 41 tokens = priv->tokens_max; 42 43 priv->limit->last = now; 44 delta = tokens - cost; 45 if (delta >= 0) { 46 priv->limit->tokens = delta; 47 spin_unlock_bh(&priv->limit->lock); 48 return priv->invert; 49 } 50 priv->limit->tokens = tokens; 51 spin_unlock_bh(&priv->limit->lock); 52 return !priv->invert; 53 } 54 55 /* Use same default as in iptables. */ 56 #define NFT_LIMIT_PKT_BURST_DEFAULT 5 57 58 static int nft_limit_init(struct nft_limit_priv *priv, 59 const struct nlattr * const tb[], bool pkts) 60 { 61 u64 unit, tokens; 62 63 if (tb[NFTA_LIMIT_RATE] == NULL || 64 tb[NFTA_LIMIT_UNIT] == NULL) 65 return -EINVAL; 66 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) 71 return -EOVERFLOW; 72 73 if (tb[NFTA_LIMIT_BURST]) 74 priv->burst = ntohl(nla_get_be32(tb[NFTA_LIMIT_BURST])); 75 76 if (pkts && priv->burst == 0) 77 priv->burst = NFT_LIMIT_PKT_BURST_DEFAULT; 78 79 if (priv->rate + priv->burst < priv->rate) 80 return -EOVERFLOW; 81 82 if (pkts) { 83 tokens = div64_u64(priv->nsecs, priv->rate) * priv->burst; 84 } else { 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. 88 */ 89 tokens = div64_u64(priv->nsecs * (priv->rate + priv->burst), 90 priv->rate); 91 } 92 93 priv->limit = kmalloc(sizeof(*priv->limit), GFP_KERNEL_ACCOUNT); 94 if (!priv->limit) 95 return -ENOMEM; 96 97 priv->limit->tokens = tokens; 98 priv->tokens_max = priv->limit->tokens; 99 100 if (tb[NFTA_LIMIT_FLAGS]) { 101 u32 flags = ntohl(nla_get_be32(tb[NFTA_LIMIT_FLAGS])); 102 103 if (flags & NFT_LIMIT_F_INV) 104 priv->invert = true; 105 } 106 priv->limit->last = ktime_get_ns(); 107 spin_lock_init(&priv->limit->lock); 108 109 return 0; 110 } 111 112 static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit_priv *priv, 113 enum nft_limit_type type) 114 { 115 u32 flags = priv->invert ? NFT_LIMIT_F_INV : 0; 116 u64 secs = div_u64(priv->nsecs, NSEC_PER_SEC); 117 118 if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate), 119 NFTA_LIMIT_PAD) || 120 nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs), 121 NFTA_LIMIT_PAD) || 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; 126 return 0; 127 128 nla_put_failure: 129 return -1; 130 } 131 132 static void nft_limit_destroy(const struct nft_ctx *ctx, 133 const struct nft_limit_priv *priv) 134 { 135 kfree(priv->limit); 136 } 137 138 static int nft_limit_clone(struct nft_limit_priv *priv_dst, 139 const struct nft_limit_priv *priv_src) 140 { 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; 146 147 priv_dst->limit = kmalloc(sizeof(*priv_dst->limit), GFP_ATOMIC); 148 if (!priv_dst->limit) 149 return -ENOMEM; 150 151 spin_lock_init(&priv_dst->limit->lock); 152 priv_dst->limit->tokens = priv_src->tokens_max; 153 priv_dst->limit->last = ktime_get_ns(); 154 155 return 0; 156 } 157 158 struct nft_limit_priv_pkts { 159 struct nft_limit_priv limit; 160 u64 cost; 161 }; 162 163 static void nft_limit_pkts_eval(const struct nft_expr *expr, 164 struct nft_regs *regs, 165 const struct nft_pktinfo *pkt) 166 { 167 struct nft_limit_priv_pkts *priv = nft_expr_priv(expr); 168 169 if (nft_limit_eval(&priv->limit, priv->cost)) 170 regs->verdict.code = NFT_BREAK; 171 } 172 173 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 }, 179 }; 180 181 static int nft_limit_pkts_init(const struct nft_ctx *ctx, 182 const struct nft_expr *expr, 183 const struct nlattr * const tb[]) 184 { 185 struct nft_limit_priv_pkts *priv = nft_expr_priv(expr); 186 int err; 187 188 err = nft_limit_init(&priv->limit, tb, true); 189 if (err < 0) 190 return err; 191 192 priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate); 193 return 0; 194 } 195 196 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr) 197 { 198 const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr); 199 200 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 201 } 202 203 static void nft_limit_pkts_destroy(const struct nft_ctx *ctx, 204 const struct nft_expr *expr) 205 { 206 const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr); 207 208 nft_limit_destroy(ctx, &priv->limit); 209 } 210 211 static int nft_limit_pkts_clone(struct nft_expr *dst, const struct nft_expr *src) 212 { 213 struct nft_limit_priv_pkts *priv_dst = nft_expr_priv(dst); 214 struct nft_limit_priv_pkts *priv_src = nft_expr_priv(src); 215 216 priv_dst->cost = priv_src->cost; 217 218 return nft_limit_clone(&priv_dst->limit, &priv_src->limit); 219 } 220 221 static struct nft_expr_type nft_limit_type; 222 static const struct nft_expr_ops nft_limit_pkts_ops = { 223 .type = &nft_limit_type, 224 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)), 225 .eval = nft_limit_pkts_eval, 226 .init = nft_limit_pkts_init, 227 .destroy = nft_limit_pkts_destroy, 228 .clone = nft_limit_pkts_clone, 229 .dump = nft_limit_pkts_dump, 230 .reduce = NFT_REDUCE_READONLY, 231 }; 232 233 static void nft_limit_bytes_eval(const struct nft_expr *expr, 234 struct nft_regs *regs, 235 const struct nft_pktinfo *pkt) 236 { 237 struct nft_limit_priv *priv = nft_expr_priv(expr); 238 u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate); 239 240 if (nft_limit_eval(priv, cost)) 241 regs->verdict.code = NFT_BREAK; 242 } 243 244 static int nft_limit_bytes_init(const struct nft_ctx *ctx, 245 const struct nft_expr *expr, 246 const struct nlattr * const tb[]) 247 { 248 struct nft_limit_priv *priv = nft_expr_priv(expr); 249 250 return nft_limit_init(priv, tb, false); 251 } 252 253 static int nft_limit_bytes_dump(struct sk_buff *skb, 254 const struct nft_expr *expr) 255 { 256 const struct nft_limit_priv *priv = nft_expr_priv(expr); 257 258 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 259 } 260 261 static void nft_limit_bytes_destroy(const struct nft_ctx *ctx, 262 const struct nft_expr *expr) 263 { 264 const struct nft_limit_priv *priv = nft_expr_priv(expr); 265 266 nft_limit_destroy(ctx, priv); 267 } 268 269 static int nft_limit_bytes_clone(struct nft_expr *dst, const struct nft_expr *src) 270 { 271 struct nft_limit_priv *priv_dst = nft_expr_priv(dst); 272 struct nft_limit_priv *priv_src = nft_expr_priv(src); 273 274 return nft_limit_clone(priv_dst, priv_src); 275 } 276 277 static const struct nft_expr_ops nft_limit_bytes_ops = { 278 .type = &nft_limit_type, 279 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv)), 280 .eval = nft_limit_bytes_eval, 281 .init = nft_limit_bytes_init, 282 .dump = nft_limit_bytes_dump, 283 .clone = nft_limit_bytes_clone, 284 .destroy = nft_limit_bytes_destroy, 285 .reduce = NFT_REDUCE_READONLY, 286 }; 287 288 static const struct nft_expr_ops * 289 nft_limit_select_ops(const struct nft_ctx *ctx, 290 const struct nlattr * const tb[]) 291 { 292 if (tb[NFTA_LIMIT_TYPE] == NULL) 293 return &nft_limit_pkts_ops; 294 295 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 296 case NFT_LIMIT_PKTS: 297 return &nft_limit_pkts_ops; 298 case NFT_LIMIT_PKT_BYTES: 299 return &nft_limit_bytes_ops; 300 } 301 return ERR_PTR(-EOPNOTSUPP); 302 } 303 304 static struct nft_expr_type nft_limit_type __read_mostly = { 305 .name = "limit", 306 .select_ops = nft_limit_select_ops, 307 .policy = nft_limit_policy, 308 .maxattr = NFTA_LIMIT_MAX, 309 .flags = NFT_EXPR_STATEFUL, 310 .owner = THIS_MODULE, 311 }; 312 313 static void nft_limit_obj_pkts_eval(struct nft_object *obj, 314 struct nft_regs *regs, 315 const struct nft_pktinfo *pkt) 316 { 317 struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 318 319 if (nft_limit_eval(&priv->limit, priv->cost)) 320 regs->verdict.code = NFT_BREAK; 321 } 322 323 static int nft_limit_obj_pkts_init(const struct nft_ctx *ctx, 324 const struct nlattr * const tb[], 325 struct nft_object *obj) 326 { 327 struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 328 int err; 329 330 err = nft_limit_init(&priv->limit, tb, true); 331 if (err < 0) 332 return err; 333 334 priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate); 335 return 0; 336 } 337 338 static int nft_limit_obj_pkts_dump(struct sk_buff *skb, 339 struct nft_object *obj, 340 bool reset) 341 { 342 const struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 343 344 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 345 } 346 347 static void nft_limit_obj_pkts_destroy(const struct nft_ctx *ctx, 348 struct nft_object *obj) 349 { 350 struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 351 352 nft_limit_destroy(ctx, &priv->limit); 353 } 354 355 static struct nft_object_type nft_limit_obj_type; 356 static const struct nft_object_ops nft_limit_obj_pkts_ops = { 357 .type = &nft_limit_obj_type, 358 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)), 359 .init = nft_limit_obj_pkts_init, 360 .destroy = nft_limit_obj_pkts_destroy, 361 .eval = nft_limit_obj_pkts_eval, 362 .dump = nft_limit_obj_pkts_dump, 363 }; 364 365 static void nft_limit_obj_bytes_eval(struct nft_object *obj, 366 struct nft_regs *regs, 367 const struct nft_pktinfo *pkt) 368 { 369 struct nft_limit_priv *priv = nft_obj_data(obj); 370 u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate); 371 372 if (nft_limit_eval(priv, cost)) 373 regs->verdict.code = NFT_BREAK; 374 } 375 376 static int nft_limit_obj_bytes_init(const struct nft_ctx *ctx, 377 const struct nlattr * const tb[], 378 struct nft_object *obj) 379 { 380 struct nft_limit_priv *priv = nft_obj_data(obj); 381 382 return nft_limit_init(priv, tb, false); 383 } 384 385 static int nft_limit_obj_bytes_dump(struct sk_buff *skb, 386 struct nft_object *obj, 387 bool reset) 388 { 389 const struct nft_limit_priv *priv = nft_obj_data(obj); 390 391 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 392 } 393 394 static void nft_limit_obj_bytes_destroy(const struct nft_ctx *ctx, 395 struct nft_object *obj) 396 { 397 struct nft_limit_priv *priv = nft_obj_data(obj); 398 399 nft_limit_destroy(ctx, priv); 400 } 401 402 static struct nft_object_type nft_limit_obj_type; 403 static const struct nft_object_ops nft_limit_obj_bytes_ops = { 404 .type = &nft_limit_obj_type, 405 .size = sizeof(struct nft_limit_priv), 406 .init = nft_limit_obj_bytes_init, 407 .destroy = nft_limit_obj_bytes_destroy, 408 .eval = nft_limit_obj_bytes_eval, 409 .dump = nft_limit_obj_bytes_dump, 410 }; 411 412 static const struct nft_object_ops * 413 nft_limit_obj_select_ops(const struct nft_ctx *ctx, 414 const struct nlattr * const tb[]) 415 { 416 if (!tb[NFTA_LIMIT_TYPE]) 417 return &nft_limit_obj_pkts_ops; 418 419 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 420 case NFT_LIMIT_PKTS: 421 return &nft_limit_obj_pkts_ops; 422 case NFT_LIMIT_PKT_BYTES: 423 return &nft_limit_obj_bytes_ops; 424 } 425 return ERR_PTR(-EOPNOTSUPP); 426 } 427 428 static struct nft_object_type nft_limit_obj_type __read_mostly = { 429 .select_ops = nft_limit_obj_select_ops, 430 .type = NFT_OBJECT_LIMIT, 431 .maxattr = NFTA_LIMIT_MAX, 432 .policy = nft_limit_policy, 433 .owner = THIS_MODULE, 434 }; 435 436 static int __init nft_limit_module_init(void) 437 { 438 int err; 439 440 err = nft_register_obj(&nft_limit_obj_type); 441 if (err < 0) 442 return err; 443 444 err = nft_register_expr(&nft_limit_type); 445 if (err < 0) 446 goto err1; 447 448 return 0; 449 err1: 450 nft_unregister_obj(&nft_limit_obj_type); 451 return err; 452 } 453 454 static void __exit nft_limit_module_exit(void) 455 { 456 nft_unregister_expr(&nft_limit_type); 457 nft_unregister_obj(&nft_limit_obj_type); 458 } 459 460 module_init(nft_limit_module_init); 461 module_exit(nft_limit_module_exit); 462 463 MODULE_LICENSE("GPL"); 464 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 465 MODULE_ALIAS_NFT_EXPR("limit"); 466 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_LIMIT); 467 MODULE_DESCRIPTION("nftables limit expression support"); 468