net/netfilter/nft_set_rbtree.c

   1 /*
   2  * Copyright (c) 2008-2009 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/rbtree.h>
  16 #include <linux/netlink.h>
  17 #include <linux/netfilter.h>
  18 #include <linux/netfilter/nf_tables.h>
  19 #include <net/netfilter/nf_tables.h>
  20
  21 struct nft_rbtree {
  22         struct rb_root          root;
  23         rwlock_t                lock;
  24         seqcount_t              count;
  25 };
  26
  27 struct nft_rbtree_elem {
  28         struct rb_node          node;
  29         struct nft_set_ext      ext;
  30 };
  31
  32 static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe)
  33 {
  34         return nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) &&
  35                (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
  36 }
  37
  38 static bool nft_rbtree_equal(const struct nft_set *set, const void *this,
  39                              const struct nft_rbtree_elem *interval)
  40 {
  41         return memcmp(this, nft_set_ext_key(&interval->ext), set->klen) == 0;
  42 }
  43
  44 static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
  45                                 const u32 *key, const struct nft_set_ext **ext,
  46                                 unsigned int seq)
  47 {
  48         struct nft_rbtree *priv = nft_set_priv(set);
  49         const struct nft_rbtree_elem *rbe, *interval = NULL;
  50         u8 genmask = nft_genmask_cur(net);
  51         const struct rb_node *parent;
  52         const void *this;
  53         int d;
  54
  55         parent = rcu_dereference_raw(priv->root.rb_node);
  56         while (parent != NULL) {
  57                 if (read_seqcount_retry(&priv->count, seq))
  58                         return false;
  59
  60                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
  61
  62                 this = nft_set_ext_key(&rbe->ext);
  63                 d = memcmp(this, key, set->klen);
  64                 if (d < 0) {
  65                         parent = rcu_dereference_raw(parent->rb_left);
  66                         if (interval &&
  67                             nft_rbtree_equal(set, this, interval) &&
  68                             nft_rbtree_interval_end(this) &&
  69                             !nft_rbtree_interval_end(interval))
  70                                 continue;
  71                         interval = rbe;
  72                 } else if (d > 0)
  73                         parent = rcu_dereference_raw(parent->rb_right);
  74                 else {
  75                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
  76                                 parent = rcu_dereference_raw(parent->rb_left);
  77                                 continue;
  78                         }
  79                         if (nft_rbtree_interval_end(rbe))
  80                                 goto out;
  81
  82                         *ext = &rbe->ext;
  83                         return true;
  84                 }
  85         }
  86
  87         if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
  88             nft_set_elem_active(&interval->ext, genmask) &&
  89             !nft_rbtree_interval_end(interval)) {
  90                 *ext = &interval->ext;
  91                 return true;
  92         }
  93 out:
  94         return false;
  95 }
  96
  97 static bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
  98                               const u32 *key, const struct nft_set_ext **ext)
  99 {
 100         struct nft_rbtree *priv = nft_set_priv(set);
 101         unsigned int seq = read_seqcount_begin(&priv->count);
 102         bool ret;
 103
 104         ret = __nft_rbtree_lookup(net, set, key, ext, seq);
 105         if (ret || !read_seqcount_retry(&priv->count, seq))
 106                 return ret;
 107
 108         read_lock_bh(&priv->lock);
 109         seq = read_seqcount_begin(&priv->count);
 110         ret = __nft_rbtree_lookup(net, set, key, ext, seq);
 111         read_unlock_bh(&priv->lock);
 112
 113         return ret;
 114 }
 115
 116 static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
 117                              const u32 *key, struct nft_rbtree_elem **elem,
 118                              unsigned int seq, unsigned int flags, u8 genmask)
 119 {
 120         struct nft_rbtree_elem *rbe, *interval = NULL;
 121         struct nft_rbtree *priv = nft_set_priv(set);
 122         const struct rb_node *parent;
 123         const void *this;
 124         int d;
 125
 126         parent = rcu_dereference_raw(priv->root.rb_node);
 127         while (parent != NULL) {
 128                 if (read_seqcount_retry(&priv->count, seq))
 129                         return false;
 130
 131                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 132
 133                 this = nft_set_ext_key(&rbe->ext);
 134                 d = memcmp(this, key, set->klen);
 135                 if (d < 0) {
 136                         parent = rcu_dereference_raw(parent->rb_left);
 137                         interval = rbe;
 138                 } else if (d > 0) {
 139                         parent = rcu_dereference_raw(parent->rb_right);
 140                 } else {
 141                         if (!nft_set_elem_active(&rbe->ext, genmask))
 142                                 parent = rcu_dereference_raw(parent->rb_left);
 143
 144                         if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
 145                             (*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
 146                             (flags & NFT_SET_ELEM_INTERVAL_END)) {
 147                                 *elem = rbe;
 148                                 return true;
 149                         }
 150                         return false;
 151                 }
 152         }
 153
 154         if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 155             nft_set_elem_active(&interval->ext, genmask) &&
 156             !nft_rbtree_interval_end(interval)) {
 157                 *elem = interval;
 158                 return true;
 159         }
 160
 161         return false;
 162 }
 163
 164 static void *nft_rbtree_get(const struct net *net, const struct nft_set *set,
 165                             const struct nft_set_elem *elem, unsigned int flags)
 166 {
 167         struct nft_rbtree *priv = nft_set_priv(set);
 168         unsigned int seq = read_seqcount_begin(&priv->count);
 169         struct nft_rbtree_elem *rbe = ERR_PTR(-ENOENT);
 170         const u32 *key = (const u32 *)&elem->key.val;
 171         u8 genmask = nft_genmask_cur(net);
 172         bool ret;
 173
 174         ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
 175         if (ret || !read_seqcount_retry(&priv->count, seq))
 176                 return rbe;
 177
 178         read_lock_bh(&priv->lock);
 179         seq = read_seqcount_begin(&priv->count);
 180         ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
 181         if (!ret)
 182                 rbe = ERR_PTR(-ENOENT);
 183         read_unlock_bh(&priv->lock);
 184
 185         return rbe;
 186 }
 187
 188 static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 189                                struct nft_rbtree_elem *new,
 190                                struct nft_set_ext **ext)
 191 {
 192         struct nft_rbtree *priv = nft_set_priv(set);
 193         u8 genmask = nft_genmask_next(net);
 194         struct nft_rbtree_elem *rbe;
 195         struct rb_node *parent, **p;
 196         int d;
 197
 198         parent = NULL;
 199         p = &priv->root.rb_node;
 200         while (*p != NULL) {
 201                 parent = *p;
 202                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 203                 d = memcmp(nft_set_ext_key(&rbe->ext),
 204                            nft_set_ext_key(&new->ext),
 205                            set->klen);
 206                 if (d < 0)
 207                         p = &parent->rb_left;
 208                 else if (d > 0)
 209                         p = &parent->rb_right;
 210                 else {
 211                         if (nft_rbtree_interval_end(rbe) &&
 212                             !nft_rbtree_interval_end(new)) {
 213                                 p = &parent->rb_left;
 214                         } else if (!nft_rbtree_interval_end(rbe) &&
 215                                    nft_rbtree_interval_end(new)) {
 216                                 p = &parent->rb_right;
 217                         } else if (nft_set_elem_active(&rbe->ext, genmask)) {
 218                                 *ext = &rbe->ext;
 219                                 return -EEXIST;
 220                         } else {
 221                                 p = &parent->rb_left;
 222                         }
 223                 }
 224         }
 225         rb_link_node_rcu(&new->node, parent, p);
 226         rb_insert_color(&new->node, &priv->root);
 227         return 0;
 228 }
 229
 230 static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 231                              const struct nft_set_elem *elem,
 232                              struct nft_set_ext **ext)
 233 {
 234         struct nft_rbtree *priv = nft_set_priv(set);
 235         struct nft_rbtree_elem *rbe = elem->priv;
 236         int err;
 237
 238         write_lock_bh(&priv->lock);
 239         write_seqcount_begin(&priv->count);
 240         err = __nft_rbtree_insert(net, set, rbe, ext);
 241         write_seqcount_end(&priv->count);
 242         write_unlock_bh(&priv->lock);
 243
 244         return err;
 245 }
 246
 247 static void nft_rbtree_remove(const struct net *net,
 248                               const struct nft_set *set,
 249                               const struct nft_set_elem *elem)
 250 {
 251         struct nft_rbtree *priv = nft_set_priv(set);
 252         struct nft_rbtree_elem *rbe = elem->priv;
 253
 254         write_lock_bh(&priv->lock);
 255         write_seqcount_begin(&priv->count);
 256         rb_erase(&rbe->node, &priv->root);
 257         write_seqcount_end(&priv->count);
 258         write_unlock_bh(&priv->lock);
 259 }
 260
 261 static void nft_rbtree_activate(const struct net *net,
 262                                 const struct nft_set *set,
 263                                 const struct nft_set_elem *elem)
 264 {
 265         struct nft_rbtree_elem *rbe = elem->priv;
 266
 267         nft_set_elem_change_active(net, set, &rbe->ext);
 268 }
 269
 270 static bool nft_rbtree_flush(const struct net *net,
 271                              const struct nft_set *set, void *priv)
 272 {
 273         struct nft_rbtree_elem *rbe = priv;
 274
 275         nft_set_elem_change_active(net, set, &rbe->ext);
 276         return true;
 277 }
 278
 279 static void *nft_rbtree_deactivate(const struct net *net,
 280                                    const struct nft_set *set,
 281                                    const struct nft_set_elem *elem)
 282 {
 283         const struct nft_rbtree *priv = nft_set_priv(set);
 284         const struct rb_node *parent = priv->root.rb_node;
 285         struct nft_rbtree_elem *rbe, *this = elem->priv;
 286         u8 genmask = nft_genmask_next(net);
 287         int d;
 288
 289         while (parent != NULL) {
 290                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 291
 292                 d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
 293                                            set->klen);
 294                 if (d < 0)
 295                         parent = parent->rb_left;
 296                 else if (d > 0)
 297                         parent = parent->rb_right;
 298                 else {
 299                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
 300                                 parent = parent->rb_left;
 301                                 continue;
 302                         }
 303                         if (nft_rbtree_interval_end(rbe) &&
 304                             !nft_rbtree_interval_end(this)) {
 305                                 parent = parent->rb_left;
 306                                 continue;
 307                         } else if (!nft_rbtree_interval_end(rbe) &&
 308                                    nft_rbtree_interval_end(this)) {
 309                                 parent = parent->rb_right;
 310                                 continue;
 311                         }
 312                         nft_rbtree_flush(net, set, rbe);
 313                         return rbe;
 314                 }
 315         }
 316         return NULL;
 317 }
 318
 319 static void nft_rbtree_walk(const struct nft_ctx *ctx,
 320                             struct nft_set *set,
 321                             struct nft_set_iter *iter)
 322 {
 323         struct nft_rbtree *priv = nft_set_priv(set);
 324         struct nft_rbtree_elem *rbe;
 325         struct nft_set_elem elem;
 326         struct rb_node *node;
 327
 328         read_lock_bh(&priv->lock);
 329         for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
 330                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 331
 332                 if (iter->count < iter->skip)
 333                         goto cont;
 334                 if (!nft_set_elem_active(&rbe->ext, iter->genmask))
 335                         goto cont;
 336
 337                 elem.priv = rbe;
 338
 339                 iter->err = iter->fn(ctx, set, iter, &elem);
 340                 if (iter->err < 0) {
 341                         read_unlock_bh(&priv->lock);
 342                         return;
 343                 }
 344 cont:
 345                 iter->count++;
 346         }
 347         read_unlock_bh(&priv->lock);
 348 }
 349
 350 static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[],
 351                                         const struct nft_set_desc *desc)
 352 {
 353         return sizeof(struct nft_rbtree);
 354 }
 355
 356 static int nft_rbtree_init(const struct nft_set *set,
 357                            const struct nft_set_desc *desc,
 358                            const struct nlattr * const nla[])
 359 {
 360         struct nft_rbtree *priv = nft_set_priv(set);
 361
 362         rwlock_init(&priv->lock);
 363         seqcount_init(&priv->count);
 364         priv->root = RB_ROOT;
 365         return 0;
 366 }
 367
 368 static void nft_rbtree_destroy(const struct nft_set *set)
 369 {
 370         struct nft_rbtree *priv = nft_set_priv(set);
 371         struct nft_rbtree_elem *rbe;
 372         struct rb_node *node;
 373
 374         while ((node = priv->root.rb_node) != NULL) {
 375                 rb_erase(node, &priv->root);
 376                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 377                 nft_set_elem_destroy(set, rbe, true);
 378         }
 379 }
 380
 381 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
 382                                 struct nft_set_estimate *est)
 383 {
 384         if (desc->size)
 385                 est->size = sizeof(struct nft_rbtree) +
 386                             desc->size * sizeof(struct nft_rbtree_elem);
 387         else
 388                 est->size = ~0;
 389
 390         est->lookup = NFT_SET_CLASS_O_LOG_N;
 391         est->space  = NFT_SET_CLASS_O_N;
 392
 393         return true;
 394 }
 395
 396 static struct nft_set_type nft_rbtree_type;
 397 static struct nft_set_ops nft_rbtree_ops __read_mostly = {
 398         .type           = &nft_rbtree_type,
 399         .privsize       = nft_rbtree_privsize,
 400         .elemsize       = offsetof(struct nft_rbtree_elem, ext),
 401         .estimate       = nft_rbtree_estimate,
 402         .init           = nft_rbtree_init,
 403         .destroy        = nft_rbtree_destroy,
 404         .insert         = nft_rbtree_insert,
 405         .remove         = nft_rbtree_remove,
 406         .deactivate     = nft_rbtree_deactivate,
 407         .flush          = nft_rbtree_flush,
 408         .activate       = nft_rbtree_activate,
 409         .lookup         = nft_rbtree_lookup,
 410         .walk           = nft_rbtree_walk,
 411         .get            = nft_rbtree_get,
 412         .features       = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT,
 413 };
 414
 415 static struct nft_set_type nft_rbtree_type __read_mostly = {
 416         .ops            = &nft_rbtree_ops,
 417         .owner          = THIS_MODULE,
 418 };
 419
 420 static int __init nft_rbtree_module_init(void)
 421 {
 422         return nft_register_set(&nft_rbtree_type);
 423 }
 424
 425 static void __exit nft_rbtree_module_exit(void)
 426 {
 427         nft_unregister_set(&nft_rbtree_type);
 428 }
 429
 430 module_init(nft_rbtree_module_init);
 431 module_exit(nft_rbtree_module_exit);
 432
 433 MODULE_LICENSE("GPL");
 434 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 435 MODULE_ALIAS_NFT_SET();