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, 197 const struct nft_expr *expr, bool reset) 198 { 199 const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr); 200 201 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 202 } 203 204 static void nft_limit_pkts_destroy(const struct nft_ctx *ctx, 205 const struct nft_expr *expr) 206 { 207 const struct nft_limit_priv_pkts *priv = nft_expr_priv(expr); 208 209 nft_limit_destroy(ctx, &priv->limit); 210 } 211 212 static int nft_limit_pkts_clone(struct nft_expr *dst, const struct nft_expr *src) 213 { 214 struct nft_limit_priv_pkts *priv_dst = nft_expr_priv(dst); 215 struct nft_limit_priv_pkts *priv_src = nft_expr_priv(src); 216 217 priv_dst->cost = priv_src->cost; 218 219 return nft_limit_clone(&priv_dst->limit, &priv_src->limit); 220 } 221 222 static struct nft_expr_type nft_limit_type; 223 static const struct nft_expr_ops nft_limit_pkts_ops = { 224 .type = &nft_limit_type, 225 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)), 226 .eval = nft_limit_pkts_eval, 227 .init = nft_limit_pkts_init, 228 .destroy = nft_limit_pkts_destroy, 229 .clone = nft_limit_pkts_clone, 230 .dump = nft_limit_pkts_dump, 231 .reduce = NFT_REDUCE_READONLY, 232 }; 233 234 static void nft_limit_bytes_eval(const struct nft_expr *expr, 235 struct nft_regs *regs, 236 const struct nft_pktinfo *pkt) 237 { 238 struct nft_limit_priv *priv = nft_expr_priv(expr); 239 u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate); 240 241 if (nft_limit_eval(priv, cost)) 242 regs->verdict.code = NFT_BREAK; 243 } 244 245 static int nft_limit_bytes_init(const struct nft_ctx *ctx, 246 const struct nft_expr *expr, 247 const struct nlattr * const tb[]) 248 { 249 struct nft_limit_priv *priv = nft_expr_priv(expr); 250 251 return nft_limit_init(priv, tb, false); 252 } 253 254 static int nft_limit_bytes_dump(struct sk_buff *skb, 255 const struct nft_expr *expr, bool reset) 256 { 257 const struct nft_limit_priv *priv = nft_expr_priv(expr); 258 259 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 260 } 261 262 static void nft_limit_bytes_destroy(const struct nft_ctx *ctx, 263 const struct nft_expr *expr) 264 { 265 const struct nft_limit_priv *priv = nft_expr_priv(expr); 266 267 nft_limit_destroy(ctx, priv); 268 } 269 270 static int nft_limit_bytes_clone(struct nft_expr *dst, const struct nft_expr *src) 271 { 272 struct nft_limit_priv *priv_dst = nft_expr_priv(dst); 273 struct nft_limit_priv *priv_src = nft_expr_priv(src); 274 275 return nft_limit_clone(priv_dst, priv_src); 276 } 277 278 static const struct nft_expr_ops nft_limit_bytes_ops = { 279 .type = &nft_limit_type, 280 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv)), 281 .eval = nft_limit_bytes_eval, 282 .init = nft_limit_bytes_init, 283 .dump = nft_limit_bytes_dump, 284 .clone = nft_limit_bytes_clone, 285 .destroy = nft_limit_bytes_destroy, 286 .reduce = NFT_REDUCE_READONLY, 287 }; 288 289 static const struct nft_expr_ops * 290 nft_limit_select_ops(const struct nft_ctx *ctx, 291 const struct nlattr * const tb[]) 292 { 293 if (tb[NFTA_LIMIT_TYPE] == NULL) 294 return &nft_limit_pkts_ops; 295 296 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 297 case NFT_LIMIT_PKTS: 298 return &nft_limit_pkts_ops; 299 case NFT_LIMIT_PKT_BYTES: 300 return &nft_limit_bytes_ops; 301 } 302 return ERR_PTR(-EOPNOTSUPP); 303 } 304 305 static struct nft_expr_type nft_limit_type __read_mostly = { 306 .name = "limit", 307 .select_ops = nft_limit_select_ops, 308 .policy = nft_limit_policy, 309 .maxattr = NFTA_LIMIT_MAX, 310 .flags = NFT_EXPR_STATEFUL, 311 .owner = THIS_MODULE, 312 }; 313 314 static void nft_limit_obj_pkts_eval(struct nft_object *obj, 315 struct nft_regs *regs, 316 const struct nft_pktinfo *pkt) 317 { 318 struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 319 320 if (nft_limit_eval(&priv->limit, priv->cost)) 321 regs->verdict.code = NFT_BREAK; 322 } 323 324 static int nft_limit_obj_pkts_init(const struct nft_ctx *ctx, 325 const struct nlattr * const tb[], 326 struct nft_object *obj) 327 { 328 struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 329 int err; 330 331 err = nft_limit_init(&priv->limit, tb, true); 332 if (err < 0) 333 return err; 334 335 priv->cost = div64_u64(priv->limit.nsecs, priv->limit.rate); 336 return 0; 337 } 338 339 static int nft_limit_obj_pkts_dump(struct sk_buff *skb, 340 struct nft_object *obj, 341 bool reset) 342 { 343 const struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 344 345 return nft_limit_dump(skb, &priv->limit, NFT_LIMIT_PKTS); 346 } 347 348 static void nft_limit_obj_pkts_destroy(const struct nft_ctx *ctx, 349 struct nft_object *obj) 350 { 351 struct nft_limit_priv_pkts *priv = nft_obj_data(obj); 352 353 nft_limit_destroy(ctx, &priv->limit); 354 } 355 356 static struct nft_object_type nft_limit_obj_type; 357 static const struct nft_object_ops nft_limit_obj_pkts_ops = { 358 .type = &nft_limit_obj_type, 359 .size = NFT_EXPR_SIZE(sizeof(struct nft_limit_priv_pkts)), 360 .init = nft_limit_obj_pkts_init, 361 .destroy = nft_limit_obj_pkts_destroy, 362 .eval = nft_limit_obj_pkts_eval, 363 .dump = nft_limit_obj_pkts_dump, 364 }; 365 366 static void nft_limit_obj_bytes_eval(struct nft_object *obj, 367 struct nft_regs *regs, 368 const struct nft_pktinfo *pkt) 369 { 370 struct nft_limit_priv *priv = nft_obj_data(obj); 371 u64 cost = div64_u64(priv->nsecs * pkt->skb->len, priv->rate); 372 373 if (nft_limit_eval(priv, cost)) 374 regs->verdict.code = NFT_BREAK; 375 } 376 377 static int nft_limit_obj_bytes_init(const struct nft_ctx *ctx, 378 const struct nlattr * const tb[], 379 struct nft_object *obj) 380 { 381 struct nft_limit_priv *priv = nft_obj_data(obj); 382 383 return nft_limit_init(priv, tb, false); 384 } 385 386 static int nft_limit_obj_bytes_dump(struct sk_buff *skb, 387 struct nft_object *obj, 388 bool reset) 389 { 390 const struct nft_limit_priv *priv = nft_obj_data(obj); 391 392 return nft_limit_dump(skb, priv, NFT_LIMIT_PKT_BYTES); 393 } 394 395 static void nft_limit_obj_bytes_destroy(const struct nft_ctx *ctx, 396 struct nft_object *obj) 397 { 398 struct nft_limit_priv *priv = nft_obj_data(obj); 399 400 nft_limit_destroy(ctx, priv); 401 } 402 403 static struct nft_object_type nft_limit_obj_type; 404 static const struct nft_object_ops nft_limit_obj_bytes_ops = { 405 .type = &nft_limit_obj_type, 406 .size = sizeof(struct nft_limit_priv), 407 .init = nft_limit_obj_bytes_init, 408 .destroy = nft_limit_obj_bytes_destroy, 409 .eval = nft_limit_obj_bytes_eval, 410 .dump = nft_limit_obj_bytes_dump, 411 }; 412 413 static const struct nft_object_ops * 414 nft_limit_obj_select_ops(const struct nft_ctx *ctx, 415 const struct nlattr * const tb[]) 416 { 417 if (!tb[NFTA_LIMIT_TYPE]) 418 return &nft_limit_obj_pkts_ops; 419 420 switch (ntohl(nla_get_be32(tb[NFTA_LIMIT_TYPE]))) { 421 case NFT_LIMIT_PKTS: 422 return &nft_limit_obj_pkts_ops; 423 case NFT_LIMIT_PKT_BYTES: 424 return &nft_limit_obj_bytes_ops; 425 } 426 return ERR_PTR(-EOPNOTSUPP); 427 } 428 429 static struct nft_object_type nft_limit_obj_type __read_mostly = { 430 .select_ops = nft_limit_obj_select_ops, 431 .type = NFT_OBJECT_LIMIT, 432 .maxattr = NFTA_LIMIT_MAX, 433 .policy = nft_limit_policy, 434 .owner = THIS_MODULE, 435 }; 436 437 static int __init nft_limit_module_init(void) 438 { 439 int err; 440 441 err = nft_register_obj(&nft_limit_obj_type); 442 if (err < 0) 443 return err; 444 445 err = nft_register_expr(&nft_limit_type); 446 if (err < 0) 447 goto err1; 448 449 return 0; 450 err1: 451 nft_unregister_obj(&nft_limit_obj_type); 452 return err; 453 } 454 455 static void __exit nft_limit_module_exit(void) 456 { 457 nft_unregister_expr(&nft_limit_type); 458 nft_unregister_obj(&nft_limit_obj_type); 459 } 460 461 module_init(nft_limit_module_init); 462 module_exit(nft_limit_module_exit); 463 464 MODULE_LICENSE("GPL"); 465 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 466 MODULE_ALIAS_NFT_EXPR("limit"); 467 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_LIMIT); 468 MODULE_DESCRIPTION("nftables limit expression support"); 469