1 /* 2 * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * Development of this code funded by Astaro AG (http://www.astaro.com/) 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/list.h> 15 #include <linux/log2.h> 16 #include <linux/jhash.h> 17 #include <linux/netlink.h> 18 #include <linux/workqueue.h> 19 #include <linux/rhashtable.h> 20 #include <linux/netfilter.h> 21 #include <linux/netfilter/nf_tables.h> 22 #include <net/netfilter/nf_tables.h> 23 24 /* We target a hash table size of 4, element hint is 75% of final size */ 25 #define NFT_RHASH_ELEMENT_HINT 3 26 27 struct nft_rhash { 28 struct rhashtable ht; 29 struct delayed_work gc_work; 30 }; 31 32 struct nft_rhash_elem { 33 struct rhash_head node; 34 struct nft_set_ext ext; 35 }; 36 37 struct nft_rhash_cmp_arg { 38 const struct nft_set *set; 39 const u32 *key; 40 u8 genmask; 41 }; 42 43 static inline u32 nft_rhash_key(const void *data, u32 len, u32 seed) 44 { 45 const struct nft_rhash_cmp_arg *arg = data; 46 47 return jhash(arg->key, len, seed); 48 } 49 50 static inline u32 nft_rhash_obj(const void *data, u32 len, u32 seed) 51 { 52 const struct nft_rhash_elem *he = data; 53 54 return jhash(nft_set_ext_key(&he->ext), len, seed); 55 } 56 57 static inline int nft_rhash_cmp(struct rhashtable_compare_arg *arg, 58 const void *ptr) 59 { 60 const struct nft_rhash_cmp_arg *x = arg->key; 61 const struct nft_rhash_elem *he = ptr; 62 63 if (memcmp(nft_set_ext_key(&he->ext), x->key, x->set->klen)) 64 return 1; 65 if (nft_set_elem_expired(&he->ext)) 66 return 1; 67 if (!nft_set_elem_active(&he->ext, x->genmask)) 68 return 1; 69 return 0; 70 } 71 72 static const struct rhashtable_params nft_rhash_params = { 73 .head_offset = offsetof(struct nft_rhash_elem, node), 74 .hashfn = nft_rhash_key, 75 .obj_hashfn = nft_rhash_obj, 76 .obj_cmpfn = nft_rhash_cmp, 77 .automatic_shrinking = true, 78 }; 79 80 static bool nft_rhash_lookup(const struct net *net, const struct nft_set *set, 81 const u32 *key, const struct nft_set_ext **ext) 82 { 83 struct nft_rhash *priv = nft_set_priv(set); 84 const struct nft_rhash_elem *he; 85 struct nft_rhash_cmp_arg arg = { 86 .genmask = nft_genmask_cur(net), 87 .set = set, 88 .key = key, 89 }; 90 91 he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params); 92 if (he != NULL) 93 *ext = &he->ext; 94 95 return !!he; 96 } 97 98 static bool nft_rhash_update(struct nft_set *set, const u32 *key, 99 void *(*new)(struct nft_set *, 100 const struct nft_expr *, 101 struct nft_regs *regs), 102 const struct nft_expr *expr, 103 struct nft_regs *regs, 104 const struct nft_set_ext **ext) 105 { 106 struct nft_rhash *priv = nft_set_priv(set); 107 struct nft_rhash_elem *he, *prev; 108 struct nft_rhash_cmp_arg arg = { 109 .genmask = NFT_GENMASK_ANY, 110 .set = set, 111 .key = key, 112 }; 113 114 he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params); 115 if (he != NULL) 116 goto out; 117 118 he = new(set, expr, regs); 119 if (he == NULL) 120 goto err1; 121 122 prev = rhashtable_lookup_get_insert_key(&priv->ht, &arg, &he->node, 123 nft_rhash_params); 124 if (IS_ERR(prev)) 125 goto err2; 126 127 /* Another cpu may race to insert the element with the same key */ 128 if (prev) { 129 nft_set_elem_destroy(set, he, true); 130 he = prev; 131 } 132 133 out: 134 *ext = &he->ext; 135 return true; 136 137 err2: 138 nft_set_elem_destroy(set, he, true); 139 err1: 140 return false; 141 } 142 143 static int nft_rhash_insert(const struct net *net, const struct nft_set *set, 144 const struct nft_set_elem *elem, 145 struct nft_set_ext **ext) 146 { 147 struct nft_rhash *priv = nft_set_priv(set); 148 struct nft_rhash_elem *he = elem->priv; 149 struct nft_rhash_cmp_arg arg = { 150 .genmask = nft_genmask_next(net), 151 .set = set, 152 .key = elem->key.val.data, 153 }; 154 struct nft_rhash_elem *prev; 155 156 prev = rhashtable_lookup_get_insert_key(&priv->ht, &arg, &he->node, 157 nft_rhash_params); 158 if (IS_ERR(prev)) 159 return PTR_ERR(prev); 160 if (prev) { 161 *ext = &prev->ext; 162 return -EEXIST; 163 } 164 return 0; 165 } 166 167 static void nft_rhash_activate(const struct net *net, const struct nft_set *set, 168 const struct nft_set_elem *elem) 169 { 170 struct nft_rhash_elem *he = elem->priv; 171 172 nft_set_elem_change_active(net, set, &he->ext); 173 nft_set_elem_clear_busy(&he->ext); 174 } 175 176 static bool nft_rhash_flush(const struct net *net, 177 const struct nft_set *set, void *priv) 178 { 179 struct nft_rhash_elem *he = priv; 180 181 if (!nft_set_elem_mark_busy(&he->ext) || 182 !nft_is_active(net, &he->ext)) { 183 nft_set_elem_change_active(net, set, &he->ext); 184 return true; 185 } 186 return false; 187 } 188 189 static void *nft_rhash_deactivate(const struct net *net, 190 const struct nft_set *set, 191 const struct nft_set_elem *elem) 192 { 193 struct nft_rhash *priv = nft_set_priv(set); 194 struct nft_rhash_elem *he; 195 struct nft_rhash_cmp_arg arg = { 196 .genmask = nft_genmask_next(net), 197 .set = set, 198 .key = elem->key.val.data, 199 }; 200 201 rcu_read_lock(); 202 he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params); 203 if (he != NULL && 204 !nft_rhash_flush(net, set, he)) 205 he = NULL; 206 207 rcu_read_unlock(); 208 209 return he; 210 } 211 212 static void nft_rhash_remove(const struct net *net, 213 const struct nft_set *set, 214 const struct nft_set_elem *elem) 215 { 216 struct nft_rhash *priv = nft_set_priv(set); 217 struct nft_rhash_elem *he = elem->priv; 218 219 rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params); 220 } 221 222 static void nft_rhash_walk(const struct nft_ctx *ctx, struct nft_set *set, 223 struct nft_set_iter *iter) 224 { 225 struct nft_rhash *priv = nft_set_priv(set); 226 struct nft_rhash_elem *he; 227 struct rhashtable_iter hti; 228 struct nft_set_elem elem; 229 int err; 230 231 err = rhashtable_walk_init(&priv->ht, &hti, GFP_ATOMIC); 232 iter->err = err; 233 if (err) 234 return; 235 236 err = rhashtable_walk_start(&hti); 237 if (err && err != -EAGAIN) { 238 iter->err = err; 239 goto out; 240 } 241 242 while ((he = rhashtable_walk_next(&hti))) { 243 if (IS_ERR(he)) { 244 err = PTR_ERR(he); 245 if (err != -EAGAIN) { 246 iter->err = err; 247 goto out; 248 } 249 250 continue; 251 } 252 253 if (iter->count < iter->skip) 254 goto cont; 255 if (nft_set_elem_expired(&he->ext)) 256 goto cont; 257 if (!nft_set_elem_active(&he->ext, iter->genmask)) 258 goto cont; 259 260 elem.priv = he; 261 262 iter->err = iter->fn(ctx, set, iter, &elem); 263 if (iter->err < 0) 264 goto out; 265 266 cont: 267 iter->count++; 268 } 269 270 out: 271 rhashtable_walk_stop(&hti); 272 rhashtable_walk_exit(&hti); 273 } 274 275 static void nft_rhash_gc(struct work_struct *work) 276 { 277 struct nft_set *set; 278 struct nft_rhash_elem *he; 279 struct nft_rhash *priv; 280 struct nft_set_gc_batch *gcb = NULL; 281 struct rhashtable_iter hti; 282 int err; 283 284 priv = container_of(work, struct nft_rhash, gc_work.work); 285 set = nft_set_container_of(priv); 286 287 err = rhashtable_walk_init(&priv->ht, &hti, GFP_KERNEL); 288 if (err) 289 goto schedule; 290 291 err = rhashtable_walk_start(&hti); 292 if (err && err != -EAGAIN) 293 goto out; 294 295 while ((he = rhashtable_walk_next(&hti))) { 296 if (IS_ERR(he)) { 297 if (PTR_ERR(he) != -EAGAIN) 298 goto out; 299 continue; 300 } 301 302 if (!nft_set_elem_expired(&he->ext)) 303 continue; 304 if (nft_set_elem_mark_busy(&he->ext)) 305 continue; 306 307 gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC); 308 if (gcb == NULL) 309 goto out; 310 rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params); 311 atomic_dec(&set->nelems); 312 nft_set_gc_batch_add(gcb, he); 313 } 314 out: 315 rhashtable_walk_stop(&hti); 316 rhashtable_walk_exit(&hti); 317 318 nft_set_gc_batch_complete(gcb); 319 schedule: 320 queue_delayed_work(system_power_efficient_wq, &priv->gc_work, 321 nft_set_gc_interval(set)); 322 } 323 324 static unsigned int nft_rhash_privsize(const struct nlattr * const nla[], 325 const struct nft_set_desc *desc) 326 { 327 return sizeof(struct nft_rhash); 328 } 329 330 static int nft_rhash_init(const struct nft_set *set, 331 const struct nft_set_desc *desc, 332 const struct nlattr * const tb[]) 333 { 334 struct nft_rhash *priv = nft_set_priv(set); 335 struct rhashtable_params params = nft_rhash_params; 336 int err; 337 338 params.nelem_hint = desc->size ?: NFT_RHASH_ELEMENT_HINT; 339 params.key_len = set->klen; 340 341 err = rhashtable_init(&priv->ht, ¶ms); 342 if (err < 0) 343 return err; 344 345 INIT_DEFERRABLE_WORK(&priv->gc_work, nft_rhash_gc); 346 if (set->flags & NFT_SET_TIMEOUT) 347 queue_delayed_work(system_power_efficient_wq, &priv->gc_work, 348 nft_set_gc_interval(set)); 349 return 0; 350 } 351 352 static void nft_rhash_elem_destroy(void *ptr, void *arg) 353 { 354 nft_set_elem_destroy(arg, ptr, true); 355 } 356 357 static void nft_rhash_destroy(const struct nft_set *set) 358 { 359 struct nft_rhash *priv = nft_set_priv(set); 360 361 cancel_delayed_work_sync(&priv->gc_work); 362 rhashtable_free_and_destroy(&priv->ht, nft_rhash_elem_destroy, 363 (void *)set); 364 } 365 366 static u32 nft_hash_buckets(u32 size) 367 { 368 return roundup_pow_of_two(size * 4 / 3); 369 } 370 371 static bool nft_rhash_estimate(const struct nft_set_desc *desc, u32 features, 372 struct nft_set_estimate *est) 373 { 374 est->size = ~0; 375 est->lookup = NFT_SET_CLASS_O_1; 376 est->space = NFT_SET_CLASS_O_N; 377 378 return true; 379 } 380 381 struct nft_hash { 382 u32 seed; 383 u32 buckets; 384 struct hlist_head table[]; 385 }; 386 387 struct nft_hash_elem { 388 struct hlist_node node; 389 struct nft_set_ext ext; 390 }; 391 392 static bool nft_hash_lookup(const struct net *net, const struct nft_set *set, 393 const u32 *key, const struct nft_set_ext **ext) 394 { 395 struct nft_hash *priv = nft_set_priv(set); 396 u8 genmask = nft_genmask_cur(net); 397 const struct nft_hash_elem *he; 398 u32 hash; 399 400 hash = jhash(key, set->klen, priv->seed); 401 hash = reciprocal_scale(hash, priv->buckets); 402 hlist_for_each_entry_rcu(he, &priv->table[hash], node) { 403 if (!memcmp(nft_set_ext_key(&he->ext), key, set->klen) && 404 nft_set_elem_active(&he->ext, genmask)) { 405 *ext = &he->ext; 406 return true; 407 } 408 } 409 return false; 410 } 411 412 /* nft_hash_select_ops() makes sure key size can be either 2 or 4 bytes . */ 413 static inline u32 nft_hash_key(const u32 *key, u32 klen) 414 { 415 if (klen == 4) 416 return *key; 417 418 return *(u16 *)key; 419 } 420 421 static bool nft_hash_lookup_fast(const struct net *net, 422 const struct nft_set *set, 423 const u32 *key, const struct nft_set_ext **ext) 424 { 425 struct nft_hash *priv = nft_set_priv(set); 426 u8 genmask = nft_genmask_cur(net); 427 const struct nft_hash_elem *he; 428 u32 hash, k1, k2; 429 430 k1 = nft_hash_key(key, set->klen); 431 hash = jhash_1word(k1, priv->seed); 432 hash = reciprocal_scale(hash, priv->buckets); 433 hlist_for_each_entry_rcu(he, &priv->table[hash], node) { 434 k2 = nft_hash_key(nft_set_ext_key(&he->ext)->data, set->klen); 435 if (k1 == k2 && 436 nft_set_elem_active(&he->ext, genmask)) { 437 *ext = &he->ext; 438 return true; 439 } 440 } 441 return false; 442 } 443 444 static int nft_hash_insert(const struct net *net, const struct nft_set *set, 445 const struct nft_set_elem *elem, 446 struct nft_set_ext **ext) 447 { 448 struct nft_hash_elem *this = elem->priv, *he; 449 struct nft_hash *priv = nft_set_priv(set); 450 u8 genmask = nft_genmask_next(net); 451 u32 hash; 452 453 hash = jhash(nft_set_ext_key(&this->ext), set->klen, priv->seed); 454 hash = reciprocal_scale(hash, priv->buckets); 455 hlist_for_each_entry(he, &priv->table[hash], node) { 456 if (!memcmp(nft_set_ext_key(&this->ext), 457 nft_set_ext_key(&he->ext), set->klen) && 458 nft_set_elem_active(&he->ext, genmask)) { 459 *ext = &he->ext; 460 return -EEXIST; 461 } 462 } 463 hlist_add_head_rcu(&this->node, &priv->table[hash]); 464 return 0; 465 } 466 467 static void nft_hash_activate(const struct net *net, const struct nft_set *set, 468 const struct nft_set_elem *elem) 469 { 470 struct nft_hash_elem *he = elem->priv; 471 472 nft_set_elem_change_active(net, set, &he->ext); 473 } 474 475 static bool nft_hash_flush(const struct net *net, 476 const struct nft_set *set, void *priv) 477 { 478 struct nft_hash_elem *he = priv; 479 480 nft_set_elem_change_active(net, set, &he->ext); 481 return true; 482 } 483 484 static void *nft_hash_deactivate(const struct net *net, 485 const struct nft_set *set, 486 const struct nft_set_elem *elem) 487 { 488 struct nft_hash *priv = nft_set_priv(set); 489 struct nft_hash_elem *this = elem->priv, *he; 490 u8 genmask = nft_genmask_next(net); 491 u32 hash; 492 493 hash = jhash(nft_set_ext_key(&this->ext), set->klen, priv->seed); 494 hash = reciprocal_scale(hash, priv->buckets); 495 hlist_for_each_entry(he, &priv->table[hash], node) { 496 if (!memcmp(nft_set_ext_key(&this->ext), &elem->key.val, 497 set->klen) || 498 nft_set_elem_active(&he->ext, genmask)) { 499 nft_set_elem_change_active(net, set, &he->ext); 500 return he; 501 } 502 } 503 return NULL; 504 } 505 506 static void nft_hash_remove(const struct net *net, 507 const struct nft_set *set, 508 const struct nft_set_elem *elem) 509 { 510 struct nft_hash_elem *he = elem->priv; 511 512 hlist_del_rcu(&he->node); 513 } 514 515 static void nft_hash_walk(const struct nft_ctx *ctx, struct nft_set *set, 516 struct nft_set_iter *iter) 517 { 518 struct nft_hash *priv = nft_set_priv(set); 519 struct nft_hash_elem *he; 520 struct nft_set_elem elem; 521 int i; 522 523 for (i = 0; i < priv->buckets; i++) { 524 hlist_for_each_entry_rcu(he, &priv->table[i], node) { 525 if (iter->count < iter->skip) 526 goto cont; 527 if (!nft_set_elem_active(&he->ext, iter->genmask)) 528 goto cont; 529 530 elem.priv = he; 531 532 iter->err = iter->fn(ctx, set, iter, &elem); 533 if (iter->err < 0) 534 return; 535 cont: 536 iter->count++; 537 } 538 } 539 } 540 541 static unsigned int nft_hash_privsize(const struct nlattr * const nla[], 542 const struct nft_set_desc *desc) 543 { 544 return sizeof(struct nft_hash) + 545 nft_hash_buckets(desc->size) * sizeof(struct hlist_head); 546 } 547 548 static int nft_hash_init(const struct nft_set *set, 549 const struct nft_set_desc *desc, 550 const struct nlattr * const tb[]) 551 { 552 struct nft_hash *priv = nft_set_priv(set); 553 554 priv->buckets = nft_hash_buckets(desc->size); 555 get_random_bytes(&priv->seed, sizeof(priv->seed)); 556 557 return 0; 558 } 559 560 static void nft_hash_destroy(const struct nft_set *set) 561 { 562 struct nft_hash *priv = nft_set_priv(set); 563 struct nft_hash_elem *he; 564 struct hlist_node *next; 565 int i; 566 567 for (i = 0; i < priv->buckets; i++) { 568 hlist_for_each_entry_safe(he, next, &priv->table[i], node) { 569 hlist_del_rcu(&he->node); 570 nft_set_elem_destroy(set, he, true); 571 } 572 } 573 } 574 575 static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features, 576 struct nft_set_estimate *est) 577 { 578 est->size = sizeof(struct nft_hash) + 579 nft_hash_buckets(desc->size) * sizeof(struct hlist_head) + 580 desc->size * sizeof(struct nft_hash_elem); 581 est->lookup = NFT_SET_CLASS_O_1; 582 est->space = NFT_SET_CLASS_O_N; 583 584 return true; 585 } 586 587 static struct nft_set_type nft_hash_type; 588 static struct nft_set_ops nft_rhash_ops __read_mostly = { 589 .type = &nft_hash_type, 590 .privsize = nft_rhash_privsize, 591 .elemsize = offsetof(struct nft_rhash_elem, ext), 592 .estimate = nft_rhash_estimate, 593 .init = nft_rhash_init, 594 .destroy = nft_rhash_destroy, 595 .insert = nft_rhash_insert, 596 .activate = nft_rhash_activate, 597 .deactivate = nft_rhash_deactivate, 598 .flush = nft_rhash_flush, 599 .remove = nft_rhash_remove, 600 .lookup = nft_rhash_lookup, 601 .update = nft_rhash_update, 602 .walk = nft_rhash_walk, 603 .features = NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT, 604 }; 605 606 static struct nft_set_ops nft_hash_ops __read_mostly = { 607 .type = &nft_hash_type, 608 .privsize = nft_hash_privsize, 609 .elemsize = offsetof(struct nft_hash_elem, ext), 610 .estimate = nft_hash_estimate, 611 .init = nft_hash_init, 612 .destroy = nft_hash_destroy, 613 .insert = nft_hash_insert, 614 .activate = nft_hash_activate, 615 .deactivate = nft_hash_deactivate, 616 .flush = nft_hash_flush, 617 .remove = nft_hash_remove, 618 .lookup = nft_hash_lookup, 619 .walk = nft_hash_walk, 620 .features = NFT_SET_MAP | NFT_SET_OBJECT, 621 }; 622 623 static struct nft_set_ops nft_hash_fast_ops __read_mostly = { 624 .type = &nft_hash_type, 625 .privsize = nft_hash_privsize, 626 .elemsize = offsetof(struct nft_hash_elem, ext), 627 .estimate = nft_hash_estimate, 628 .init = nft_hash_init, 629 .destroy = nft_hash_destroy, 630 .insert = nft_hash_insert, 631 .activate = nft_hash_activate, 632 .deactivate = nft_hash_deactivate, 633 .flush = nft_hash_flush, 634 .remove = nft_hash_remove, 635 .lookup = nft_hash_lookup_fast, 636 .walk = nft_hash_walk, 637 .features = NFT_SET_MAP | NFT_SET_OBJECT, 638 }; 639 640 static const struct nft_set_ops * 641 nft_hash_select_ops(const struct nft_ctx *ctx, const struct nft_set_desc *desc, 642 u32 flags) 643 { 644 if (desc->size) { 645 switch (desc->klen) { 646 case 4: 647 return &nft_hash_fast_ops; 648 default: 649 return &nft_hash_ops; 650 } 651 } 652 653 return &nft_rhash_ops; 654 } 655 656 static struct nft_set_type nft_hash_type __read_mostly = { 657 .select_ops = nft_hash_select_ops, 658 .owner = THIS_MODULE, 659 }; 660 661 static int __init nft_hash_module_init(void) 662 { 663 return nft_register_set(&nft_hash_type); 664 } 665 666 static void __exit nft_hash_module_exit(void) 667 { 668 nft_unregister_set(&nft_hash_type); 669 } 670 671 module_init(nft_hash_module_init); 672 module_exit(nft_hash_module_exit); 673 674 MODULE_LICENSE("GPL"); 675 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 676 MODULE_ALIAS_NFT_SET(); 677
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