net/netfilter/nft_set_rbtree.c

   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/list.h>
  12 #include <linux/rbtree.h>
  13 #include <linux/netlink.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/netfilter/nf_tables.h>
  16 #include <net/netfilter/nf_tables_core.h>
  17
  18 struct nft_rbtree {
  19         struct rb_root          root;
  20         rwlock_t                lock;
  21         seqcount_rwlock_t       count;
  22         unsigned long           last_gc;
  23 };
  24
  25 struct nft_rbtree_elem {
  26         struct nft_elem_priv    priv;
  27         struct rb_node          node;
  28         struct nft_set_ext      ext;
  29 };
  30
  31 static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe)
  32 {
  33         return nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) &&
  34                (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
  35 }
  36
  37 static bool nft_rbtree_interval_start(const struct nft_rbtree_elem *rbe)
  38 {
  39         return !nft_rbtree_interval_end(rbe);
  40 }
  41
  42 static int nft_rbtree_cmp(const struct nft_set *set,
  43                           const struct nft_rbtree_elem *e1,
  44                           const struct nft_rbtree_elem *e2)
  45 {
  46         return memcmp(nft_set_ext_key(&e1->ext), nft_set_ext_key(&e2->ext),
  47                       set->klen);
  48 }
  49
  50 static bool nft_rbtree_elem_expired(const struct nft_rbtree_elem *rbe)
  51 {
  52         return nft_set_elem_expired(&rbe->ext);
  53 }
  54
  55 static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
  56                                 const u32 *key, const struct nft_set_ext **ext,
  57                                 unsigned int seq)
  58 {
  59         struct nft_rbtree *priv = nft_set_priv(set);
  60         const struct nft_rbtree_elem *rbe, *interval = NULL;
  61         u8 genmask = nft_genmask_cur(net);
  62         const struct rb_node *parent;
  63         int d;
  64
  65         parent = rcu_dereference_raw(priv->root.rb_node);
  66         while (parent != NULL) {
  67                 if (read_seqcount_retry(&priv->count, seq))
  68                         return false;
  69
  70                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
  71
  72                 d = memcmp(nft_set_ext_key(&rbe->ext), key, set->klen);
  73                 if (d < 0) {
  74                         parent = rcu_dereference_raw(parent->rb_left);
  75                         if (interval &&
  76                             !nft_rbtree_cmp(set, rbe, interval) &&
  77                             nft_rbtree_interval_end(rbe) &&
  78                             nft_rbtree_interval_start(interval))
  79                                 continue;
  80                         interval = rbe;
  81                 } else if (d > 0)
  82                         parent = rcu_dereference_raw(parent->rb_right);
  83                 else {
  84                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
  85                                 parent = rcu_dereference_raw(parent->rb_left);
  86                                 continue;
  87                         }
  88
  89                         if (nft_rbtree_elem_expired(rbe))
  90                                 return false;
  91
  92                         if (nft_rbtree_interval_end(rbe)) {
  93                                 if (nft_set_is_anonymous(set))
  94                                         return false;
  95                                 parent = rcu_dereference_raw(parent->rb_left);
  96                                 interval = NULL;
  97                                 continue;
  98                         }
  99
 100                         *ext = &rbe->ext;
 101                         return true;
 102                 }
 103         }
 104
 105         if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 106             nft_set_elem_active(&interval->ext, genmask) &&
 107             !nft_rbtree_elem_expired(interval) &&
 108             nft_rbtree_interval_start(interval)) {
 109                 *ext = &interval->ext;
 110                 return true;
 111         }
 112
 113         return false;
 114 }
 115
 116 INDIRECT_CALLABLE_SCOPE
 117 bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
 118                        const u32 *key, const struct nft_set_ext **ext)
 119 {
 120         struct nft_rbtree *priv = nft_set_priv(set);
 121         unsigned int seq = read_seqcount_begin(&priv->count);
 122         bool ret;
 123
 124         ret = __nft_rbtree_lookup(net, set, key, ext, seq);
 125         if (ret || !read_seqcount_retry(&priv->count, seq))
 126                 return ret;
 127
 128         read_lock_bh(&priv->lock);
 129         seq = read_seqcount_begin(&priv->count);
 130         ret = __nft_rbtree_lookup(net, set, key, ext, seq);
 131         read_unlock_bh(&priv->lock);
 132
 133         return ret;
 134 }
 135
 136 static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
 137                              const u32 *key, struct nft_rbtree_elem **elem,
 138                              unsigned int seq, unsigned int flags, u8 genmask)
 139 {
 140         struct nft_rbtree_elem *rbe, *interval = NULL;
 141         struct nft_rbtree *priv = nft_set_priv(set);
 142         const struct rb_node *parent;
 143         const void *this;
 144         int d;
 145
 146         parent = rcu_dereference_raw(priv->root.rb_node);
 147         while (parent != NULL) {
 148                 if (read_seqcount_retry(&priv->count, seq))
 149                         return false;
 150
 151                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 152
 153                 this = nft_set_ext_key(&rbe->ext);
 154                 d = memcmp(this, key, set->klen);
 155                 if (d < 0) {
 156                         parent = rcu_dereference_raw(parent->rb_left);
 157                         if (!(flags & NFT_SET_ELEM_INTERVAL_END))
 158                                 interval = rbe;
 159                 } else if (d > 0) {
 160                         parent = rcu_dereference_raw(parent->rb_right);
 161                         if (flags & NFT_SET_ELEM_INTERVAL_END)
 162                                 interval = rbe;
 163                 } else {
 164                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
 165                                 parent = rcu_dereference_raw(parent->rb_left);
 166                                 continue;
 167                         }
 168
 169                         if (nft_set_elem_expired(&rbe->ext))
 170                                 return false;
 171
 172                         if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
 173                             (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
 174                             (flags & NFT_SET_ELEM_INTERVAL_END)) {
 175                                 *elem = rbe;
 176                                 return true;
 177                         }
 178
 179                         if (nft_rbtree_interval_end(rbe))
 180                                 interval = NULL;
 181
 182                         parent = rcu_dereference_raw(parent->rb_left);
 183                 }
 184         }
 185
 186         if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 187             nft_set_elem_active(&interval->ext, genmask) &&
 188             !nft_set_elem_expired(&interval->ext) &&
 189             ((!nft_rbtree_interval_end(interval) &&
 190               !(flags & NFT_SET_ELEM_INTERVAL_END)) ||
 191              (nft_rbtree_interval_end(interval) &&
 192               (flags & NFT_SET_ELEM_INTERVAL_END)))) {
 193                 *elem = interval;
 194                 return true;
 195         }
 196
 197         return false;
 198 }
 199
 200 static struct nft_elem_priv *
 201 nft_rbtree_get(const struct net *net, const struct nft_set *set,
 202                const struct nft_set_elem *elem, unsigned int flags)
 203 {
 204         struct nft_rbtree *priv = nft_set_priv(set);
 205         unsigned int seq = read_seqcount_begin(&priv->count);
 206         struct nft_rbtree_elem *rbe = ERR_PTR(-ENOENT);
 207         const u32 *key = (const u32 *)&elem->key.val;
 208         u8 genmask = nft_genmask_cur(net);
 209         bool ret;
 210
 211         ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
 212         if (ret || !read_seqcount_retry(&priv->count, seq))
 213                 return &rbe->priv;
 214
 215         read_lock_bh(&priv->lock);
 216         seq = read_seqcount_begin(&priv->count);
 217         ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
 218         read_unlock_bh(&priv->lock);
 219
 220         if (!ret)
 221                 return ERR_PTR(-ENOENT);
 222
 223         return &rbe->priv;
 224 }
 225
 226 static void nft_rbtree_gc_elem_remove(struct net *net, struct nft_set *set,
 227                                       struct nft_rbtree *priv,
 228                                       struct nft_rbtree_elem *rbe)
 229 {
 230         lockdep_assert_held_write(&priv->lock);
 231         nft_setelem_data_deactivate(net, set, &rbe->priv);
 232         rb_erase(&rbe->node, &priv->root);
 233 }
 234
 235 static const struct nft_rbtree_elem *
 236 nft_rbtree_gc_elem(const struct nft_set *__set, struct nft_rbtree *priv,
 237                    struct nft_rbtree_elem *rbe)
 238 {
 239         struct nft_set *set = (struct nft_set *)__set;
 240         struct rb_node *prev = rb_prev(&rbe->node);
 241         struct net *net = read_pnet(&set->net);
 242         struct nft_rbtree_elem *rbe_prev;
 243         struct nft_trans_gc *gc;
 244
 245         gc = nft_trans_gc_alloc(set, 0, GFP_ATOMIC);
 246         if (!gc)
 247                 return ERR_PTR(-ENOMEM);
 248
 249         /* search for end interval coming before this element.
 250          * end intervals don't carry a timeout extension, they
 251          * are coupled with the interval start element.
 252          */
 253         while (prev) {
 254                 rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
 255                 if (nft_rbtree_interval_end(rbe_prev) &&
 256                     nft_set_elem_active(&rbe_prev->ext, NFT_GENMASK_ANY))
 257                         break;
 258
 259                 prev = rb_prev(prev);
 260         }
 261
 262         rbe_prev = NULL;
 263         if (prev) {
 264                 rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
 265                 nft_rbtree_gc_elem_remove(net, set, priv, rbe_prev);
 266
 267                 /* There is always room in this trans gc for this element,
 268                  * memory allocation never actually happens, hence, the warning
 269                  * splat in such case. No need to set NFT_SET_ELEM_DEAD_BIT,
 270                  * this is synchronous gc which never fails.
 271                  */
 272                 gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
 273                 if (WARN_ON_ONCE(!gc))
 274                         return ERR_PTR(-ENOMEM);
 275
 276                 nft_trans_gc_elem_add(gc, rbe_prev);
 277         }
 278
 279         nft_rbtree_gc_elem_remove(net, set, priv, rbe);
 280         gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
 281         if (WARN_ON_ONCE(!gc))
 282                 return ERR_PTR(-ENOMEM);
 283
 284         nft_trans_gc_elem_add(gc, rbe);
 285
 286         nft_trans_gc_queue_sync_done(gc);
 287
 288         return rbe_prev;
 289 }
 290
 291 static bool nft_rbtree_update_first(const struct nft_set *set,
 292                                     struct nft_rbtree_elem *rbe,
 293                                     struct rb_node *first)
 294 {
 295         struct nft_rbtree_elem *first_elem;
 296
 297         first_elem = rb_entry(first, struct nft_rbtree_elem, node);
 298         /* this element is closest to where the new element is to be inserted:
 299          * update the first element for the node list path.
 300          */
 301         if (nft_rbtree_cmp(set, rbe, first_elem) < 0)
 302                 return true;
 303
 304         return false;
 305 }
 306
 307 static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 308                                struct nft_rbtree_elem *new,
 309                                struct nft_elem_priv **elem_priv)
 310 {
 311         struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL;
 312         struct rb_node *node, *next, *parent, **p, *first = NULL;
 313         struct nft_rbtree *priv = nft_set_priv(set);
 314         u8 cur_genmask = nft_genmask_cur(net);
 315         u8 genmask = nft_genmask_next(net);
 316         u64 tstamp = nft_net_tstamp(net);
 317         int d;
 318
 319         /* Descend the tree to search for an existing element greater than the
 320          * key value to insert that is greater than the new element. This is the
 321          * first element to walk the ordered elements to find possible overlap.
 322          */
 323         parent = NULL;
 324         p = &priv->root.rb_node;
 325         while (*p != NULL) {
 326                 parent = *p;
 327                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 328                 d = nft_rbtree_cmp(set, rbe, new);
 329
 330                 if (d < 0) {
 331                         p = &parent->rb_left;
 332                 } else if (d > 0) {
 333                         if (!first ||
 334                             nft_rbtree_update_first(set, rbe, first))
 335                                 first = &rbe->node;
 336
 337                         p = &parent->rb_right;
 338                 } else {
 339                         if (nft_rbtree_interval_end(rbe))
 340                                 p = &parent->rb_left;
 341                         else
 342                                 p = &parent->rb_right;
 343                 }
 344         }
 345
 346         if (!first)
 347                 first = rb_first(&priv->root);
 348
 349         /* Detect overlap by going through the list of valid tree nodes.
 350          * Values stored in the tree are in reversed order, starting from
 351          * highest to lowest value.
 352          */
 353         for (node = first; node != NULL; node = next) {
 354                 next = rb_next(node);
 355
 356                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 357
 358                 if (!nft_set_elem_active(&rbe->ext, genmask))
 359                         continue;
 360
 361                 /* perform garbage collection to avoid bogus overlap reports
 362                  * but skip new elements in this transaction.
 363                  */
 364                 if (__nft_set_elem_expired(&rbe->ext, tstamp) &&
 365                     nft_set_elem_active(&rbe->ext, cur_genmask)) {
 366                         const struct nft_rbtree_elem *removed_end;
 367
 368                         removed_end = nft_rbtree_gc_elem(set, priv, rbe);
 369                         if (IS_ERR(removed_end))
 370                                 return PTR_ERR(removed_end);
 371
 372                         if (removed_end == rbe_le || removed_end == rbe_ge)
 373                                 return -EAGAIN;
 374
 375                         continue;
 376                 }
 377
 378                 d = nft_rbtree_cmp(set, rbe, new);
 379                 if (d == 0) {
 380                         /* Matching end element: no need to look for an
 381                          * overlapping greater or equal element.
 382                          */
 383                         if (nft_rbtree_interval_end(rbe)) {
 384                                 rbe_le = rbe;
 385                                 break;
 386                         }
 387
 388                         /* first element that is greater or equal to key value. */
 389                         if (!rbe_ge) {
 390                                 rbe_ge = rbe;
 391                                 continue;
 392                         }
 393
 394                         /* this is a closer more or equal element, update it. */
 395                         if (nft_rbtree_cmp(set, rbe_ge, new) != 0) {
 396                                 rbe_ge = rbe;
 397                                 continue;
 398                         }
 399
 400                         /* element is equal to key value, make sure flags are
 401                          * the same, an existing more or equal start element
 402                          * must not be replaced by more or equal end element.
 403                          */
 404                         if ((nft_rbtree_interval_start(new) &&
 405                              nft_rbtree_interval_start(rbe_ge)) ||
 406                             (nft_rbtree_interval_end(new) &&
 407                              nft_rbtree_interval_end(rbe_ge))) {
 408                                 rbe_ge = rbe;
 409                                 continue;
 410                         }
 411                 } else if (d > 0) {
 412                         /* annotate element greater than the new element. */
 413                         rbe_ge = rbe;
 414                         continue;
 415                 } else if (d < 0) {
 416                         /* annotate element less than the new element. */
 417                         rbe_le = rbe;
 418                         break;
 419                 }
 420         }
 421
 422         /* - new start element matching existing start element: full overlap
 423          *   reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given.
 424          */
 425         if (rbe_ge && !nft_rbtree_cmp(set, new, rbe_ge) &&
 426             nft_rbtree_interval_start(rbe_ge) == nft_rbtree_interval_start(new)) {
 427                 *elem_priv = &rbe_ge->priv;
 428                 return -EEXIST;
 429         }
 430
 431         /* - new end element matching existing end element: full overlap
 432          *   reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given.
 433          */
 434         if (rbe_le && !nft_rbtree_cmp(set, new, rbe_le) &&
 435             nft_rbtree_interval_end(rbe_le) == nft_rbtree_interval_end(new)) {
 436                 *elem_priv = &rbe_le->priv;
 437                 return -EEXIST;
 438         }
 439
 440         /* - new start element with existing closest, less or equal key value
 441          *   being a start element: partial overlap, reported as -ENOTEMPTY.
 442          *   Anonymous sets allow for two consecutive start element since they
 443          *   are constant, skip them to avoid bogus overlap reports.
 444          */
 445         if (!nft_set_is_anonymous(set) && rbe_le &&
 446             nft_rbtree_interval_start(rbe_le) && nft_rbtree_interval_start(new))
 447                 return -ENOTEMPTY;
 448
 449         /* - new end element with existing closest, less or equal key value
 450          *   being a end element: partial overlap, reported as -ENOTEMPTY.
 451          */
 452         if (rbe_le &&
 453             nft_rbtree_interval_end(rbe_le) && nft_rbtree_interval_end(new))
 454                 return -ENOTEMPTY;
 455
 456         /* - new end element with existing closest, greater or equal key value
 457          *   being an end element: partial overlap, reported as -ENOTEMPTY
 458          */
 459         if (rbe_ge &&
 460             nft_rbtree_interval_end(rbe_ge) && nft_rbtree_interval_end(new))
 461                 return -ENOTEMPTY;
 462
 463         /* Accepted element: pick insertion point depending on key value */
 464         parent = NULL;
 465         p = &priv->root.rb_node;
 466         while (*p != NULL) {
 467                 parent = *p;
 468                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 469                 d = nft_rbtree_cmp(set, rbe, new);
 470
 471                 if (d < 0)
 472                         p = &parent->rb_left;
 473                 else if (d > 0)
 474                         p = &parent->rb_right;
 475                 else if (nft_rbtree_interval_end(rbe))
 476                         p = &parent->rb_left;
 477                 else
 478                         p = &parent->rb_right;
 479         }
 480
 481         rb_link_node_rcu(&new->node, parent, p);
 482         rb_insert_color(&new->node, &priv->root);
 483         return 0;
 484 }
 485
 486 static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 487                              const struct nft_set_elem *elem,
 488                              struct nft_elem_priv **elem_priv)
 489 {
 490         struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem->priv);
 491         struct nft_rbtree *priv = nft_set_priv(set);
 492         int err;
 493
 494         do {
 495                 if (fatal_signal_pending(current))
 496                         return -EINTR;
 497
 498                 cond_resched();
 499
 500                 write_lock_bh(&priv->lock);
 501                 write_seqcount_begin(&priv->count);
 502                 err = __nft_rbtree_insert(net, set, rbe, elem_priv);
 503                 write_seqcount_end(&priv->count);
 504                 write_unlock_bh(&priv->lock);
 505         } while (err == -EAGAIN);
 506
 507         return err;
 508 }
 509
 510 static void nft_rbtree_erase(struct nft_rbtree *priv, struct nft_rbtree_elem *rbe)
 511 {
 512         write_lock_bh(&priv->lock);
 513         write_seqcount_begin(&priv->count);
 514         rb_erase(&rbe->node, &priv->root);
 515         write_seqcount_end(&priv->count);
 516         write_unlock_bh(&priv->lock);
 517 }
 518
 519 static void nft_rbtree_remove(const struct net *net,
 520                               const struct nft_set *set,
 521                               struct nft_elem_priv *elem_priv)
 522 {
 523         struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem_priv);
 524         struct nft_rbtree *priv = nft_set_priv(set);
 525
 526         nft_rbtree_erase(priv, rbe);
 527 }
 528
 529 static void nft_rbtree_activate(const struct net *net,
 530                                 const struct nft_set *set,
 531                                 struct nft_elem_priv *elem_priv)
 532 {
 533         struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem_priv);
 534
 535         nft_set_elem_change_active(net, set, &rbe->ext);
 536 }
 537
 538 static void nft_rbtree_flush(const struct net *net,
 539                              const struct nft_set *set,
 540                              struct nft_elem_priv *elem_priv)
 541 {
 542         struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem_priv);
 543
 544         nft_set_elem_change_active(net, set, &rbe->ext);
 545 }
 546
 547 static struct nft_elem_priv *
 548 nft_rbtree_deactivate(const struct net *net, const struct nft_set *set,
 549                       const struct nft_set_elem *elem)
 550 {
 551         struct nft_rbtree_elem *rbe, *this = nft_elem_priv_cast(elem->priv);
 552         const struct nft_rbtree *priv = nft_set_priv(set);
 553         const struct rb_node *parent = priv->root.rb_node;
 554         u8 genmask = nft_genmask_next(net);
 555         u64 tstamp = nft_net_tstamp(net);
 556         int d;
 557
 558         while (parent != NULL) {
 559                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 560
 561                 d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
 562                                            set->klen);
 563                 if (d < 0)
 564                         parent = parent->rb_left;
 565                 else if (d > 0)
 566                         parent = parent->rb_right;
 567                 else {
 568                         if (nft_rbtree_interval_end(rbe) &&
 569                             nft_rbtree_interval_start(this)) {
 570                                 parent = parent->rb_left;
 571                                 continue;
 572                         } else if (nft_rbtree_interval_start(rbe) &&
 573                                    nft_rbtree_interval_end(this)) {
 574                                 parent = parent->rb_right;
 575                                 continue;
 576                         } else if (__nft_set_elem_expired(&rbe->ext, tstamp)) {
 577                                 break;
 578                         } else if (!nft_set_elem_active(&rbe->ext, genmask)) {
 579                                 parent = parent->rb_left;
 580                                 continue;
 581                         }
 582                         nft_rbtree_flush(net, set, &rbe->priv);
 583                         return &rbe->priv;
 584                 }
 585         }
 586         return NULL;
 587 }
 588
 589 static void nft_rbtree_walk(const struct nft_ctx *ctx,
 590                             struct nft_set *set,
 591                             struct nft_set_iter *iter)
 592 {
 593         struct nft_rbtree *priv = nft_set_priv(set);
 594         struct nft_rbtree_elem *rbe;
 595         struct rb_node *node;
 596
 597         read_lock_bh(&priv->lock);
 598         for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
 599                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 600
 601                 if (iter->count < iter->skip)
 602                         goto cont;
 603                 if (!nft_set_elem_active(&rbe->ext, iter->genmask))
 604                         goto cont;
 605
 606                 iter->err = iter->fn(ctx, set, iter, &rbe->priv);
 607                 if (iter->err < 0) {
 608                         read_unlock_bh(&priv->lock);
 609                         return;
 610                 }
 611 cont:
 612                 iter->count++;
 613         }
 614         read_unlock_bh(&priv->lock);
 615 }
 616
 617 static void nft_rbtree_gc_remove(struct net *net, struct nft_set *set,
 618                                  struct nft_rbtree *priv,
 619                                  struct nft_rbtree_elem *rbe)
 620 {
 621         nft_setelem_data_deactivate(net, set, &rbe->priv);
 622         nft_rbtree_erase(priv, rbe);
 623 }
 624
 625 static void nft_rbtree_gc(struct nft_set *set)
 626 {
 627         struct nft_rbtree *priv = nft_set_priv(set);
 628         struct nft_rbtree_elem *rbe, *rbe_end = NULL;
 629         struct net *net = read_pnet(&set->net);
 630         u64 tstamp = nft_net_tstamp(net);
 631         struct rb_node *node, *next;
 632         struct nft_trans_gc *gc;
 633
 634         set  = nft_set_container_of(priv);
 635         net  = read_pnet(&set->net);
 636
 637         gc = nft_trans_gc_alloc(set, 0, GFP_KERNEL);
 638         if (!gc)
 639                 return;
 640
 641         for (node = rb_first(&priv->root); node ; node = next) {
 642                 next = rb_next(node);
 643
 644                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 645
 646                 /* elements are reversed in the rbtree for historical reasons,
 647                  * from highest to lowest value, that is why end element is
 648                  * always visited before the start element.
 649                  */
 650                 if (nft_rbtree_interval_end(rbe)) {
 651                         rbe_end = rbe;
 652                         continue;
 653                 }
 654                 if (!__nft_set_elem_expired(&rbe->ext, tstamp))
 655                         continue;
 656
 657                 gc = nft_trans_gc_queue_sync(gc, GFP_KERNEL);
 658                 if (!gc)
 659                         goto try_later;
 660
 661                 /* end element needs to be removed first, it has
 662                  * no timeout extension.
 663                  */
 664                 if (rbe_end) {
 665                         nft_rbtree_gc_remove(net, set, priv, rbe_end);
 666                         nft_trans_gc_elem_add(gc, rbe_end);
 667                         rbe_end = NULL;
 668                 }
 669
 670                 gc = nft_trans_gc_queue_sync(gc, GFP_KERNEL);
 671                 if (!gc)
 672                         goto try_later;
 673
 674                 nft_rbtree_gc_remove(net, set, priv, rbe);
 675                 nft_trans_gc_elem_add(gc, rbe);
 676         }
 677
 678 try_later:
 679
 680         if (gc) {
 681                 gc = nft_trans_gc_catchall_sync(gc);
 682                 nft_trans_gc_queue_sync_done(gc);
 683                 priv->last_gc = jiffies;
 684         }
 685 }
 686
 687 static u64 nft_rbtree_privsize(const struct nlattr * const nla[],
 688                                const struct nft_set_desc *desc)
 689 {
 690         return sizeof(struct nft_rbtree);
 691 }
 692
 693 static int nft_rbtree_init(const struct nft_set *set,
 694                            const struct nft_set_desc *desc,
 695                            const struct nlattr * const nla[])
 696 {
 697         struct nft_rbtree *priv = nft_set_priv(set);
 698
 699         BUILD_BUG_ON(offsetof(struct nft_rbtree_elem, priv) != 0);
 700
 701         rwlock_init(&priv->lock);
 702         seqcount_rwlock_init(&priv->count, &priv->lock);
 703         priv->root = RB_ROOT;
 704
 705         return 0;
 706 }
 707
 708 static void nft_rbtree_destroy(const struct nft_ctx *ctx,
 709                                const struct nft_set *set)
 710 {
 711         struct nft_rbtree *priv = nft_set_priv(set);
 712         struct nft_rbtree_elem *rbe;
 713         struct rb_node *node;
 714
 715         while ((node = priv->root.rb_node) != NULL) {
 716                 rb_erase(node, &priv->root);
 717                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 718                 nf_tables_set_elem_destroy(ctx, set, &rbe->priv);
 719         }
 720 }
 721
 722 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
 723                                 struct nft_set_estimate *est)
 724 {
 725         if (desc->field_count > 1)
 726                 return false;
 727
 728         if (desc->size)
 729                 est->size = sizeof(struct nft_rbtree) +
 730                             desc->size * sizeof(struct nft_rbtree_elem);
 731         else
 732                 est->size = ~0;
 733
 734         est->lookup = NFT_SET_CLASS_O_LOG_N;
 735         est->space  = NFT_SET_CLASS_O_N;
 736
 737         return true;
 738 }
 739
 740 static void nft_rbtree_commit(struct nft_set *set)
 741 {
 742         struct nft_rbtree *priv = nft_set_priv(set);
 743
 744         if (time_after_eq(jiffies, priv->last_gc + nft_set_gc_interval(set)))
 745                 nft_rbtree_gc(set);
 746 }
 747
 748 static void nft_rbtree_gc_init(const struct nft_set *set)
 749 {
 750         struct nft_rbtree *priv = nft_set_priv(set);
 751
 752         priv->last_gc = jiffies;
 753 }
 754
 755 const struct nft_set_type nft_set_rbtree_type = {
 756         .features       = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT,
 757         .ops            = {
 758                 .privsize       = nft_rbtree_privsize,
 759                 .elemsize       = offsetof(struct nft_rbtree_elem, ext),
 760                 .estimate       = nft_rbtree_estimate,
 761                 .init           = nft_rbtree_init,
 762                 .destroy        = nft_rbtree_destroy,
 763                 .insert         = nft_rbtree_insert,
 764                 .remove         = nft_rbtree_remove,
 765                 .deactivate     = nft_rbtree_deactivate,
 766                 .flush          = nft_rbtree_flush,
 767                 .activate       = nft_rbtree_activate,
 768                 .commit         = nft_rbtree_commit,
 769                 .gc_init        = nft_rbtree_gc_init,
 770                 .lookup         = nft_rbtree_lookup,
 771                 .walk           = nft_rbtree_walk,
 772                 .get            = nft_rbtree_get,
 773         },
 774 };