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