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 int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 117                                struct nft_rbtree_elem *new,
 118                                struct nft_set_ext **ext)
 119 {
 120         struct nft_rbtree *priv = nft_set_priv(set);
 121         u8 genmask = nft_genmask_next(net);
 122         struct nft_rbtree_elem *rbe;
 123         struct rb_node *parent, **p;
 124         int d;
 125
 126         parent = NULL;
 127         p = &priv->root.rb_node;
 128         while (*p != NULL) {
 129                 parent = *p;
 130                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 131                 d = memcmp(nft_set_ext_key(&rbe->ext),
 132                            nft_set_ext_key(&new->ext),
 133                            set->klen);
 134                 if (d < 0)
 135                         p = &parent->rb_left;
 136                 else if (d > 0)
 137                         p = &parent->rb_right;
 138                 else {
 139                         if (nft_rbtree_interval_end(rbe) &&
 140                             !nft_rbtree_interval_end(new)) {
 141                                 p = &parent->rb_left;
 142                         } else if (!nft_rbtree_interval_end(rbe) &&
 143                                    nft_rbtree_interval_end(new)) {
 144                                 p = &parent->rb_right;
 145                         } else if (nft_set_elem_active(&rbe->ext, genmask)) {
 146                                 *ext = &rbe->ext;
 147                                 return -EEXIST;
 148                         } else {
 149                                 p = &parent->rb_left;
 150                         }
 151                 }
 152         }
 153         rb_link_node_rcu(&new->node, parent, p);
 154         rb_insert_color(&new->node, &priv->root);
 155         return 0;
 156 }
 157
 158 static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 159                              const struct nft_set_elem *elem,
 160                              struct nft_set_ext **ext)
 161 {
 162         struct nft_rbtree *priv = nft_set_priv(set);
 163         struct nft_rbtree_elem *rbe = elem->priv;
 164         int err;
 165
 166         write_lock_bh(&priv->lock);
 167         write_seqcount_begin(&priv->count);
 168         err = __nft_rbtree_insert(net, set, rbe, ext);
 169         write_seqcount_end(&priv->count);
 170         write_unlock_bh(&priv->lock);
 171
 172         return err;
 173 }
 174
 175 static void nft_rbtree_remove(const struct net *net,
 176                               const struct nft_set *set,
 177                               const struct nft_set_elem *elem)
 178 {
 179         struct nft_rbtree *priv = nft_set_priv(set);
 180         struct nft_rbtree_elem *rbe = elem->priv;
 181
 182         write_lock_bh(&priv->lock);
 183         write_seqcount_begin(&priv->count);
 184         rb_erase(&rbe->node, &priv->root);
 185         write_seqcount_end(&priv->count);
 186         write_unlock_bh(&priv->lock);
 187 }
 188
 189 static void nft_rbtree_activate(const struct net *net,
 190                                 const struct nft_set *set,
 191                                 const struct nft_set_elem *elem)
 192 {
 193         struct nft_rbtree_elem *rbe = elem->priv;
 194
 195         nft_set_elem_change_active(net, set, &rbe->ext);
 196 }
 197
 198 static bool nft_rbtree_flush(const struct net *net,
 199                              const struct nft_set *set, void *priv)
 200 {
 201         struct nft_rbtree_elem *rbe = priv;
 202
 203         nft_set_elem_change_active(net, set, &rbe->ext);
 204         return true;
 205 }
 206
 207 static void *nft_rbtree_deactivate(const struct net *net,
 208                                    const struct nft_set *set,
 209                                    const struct nft_set_elem *elem)
 210 {
 211         const struct nft_rbtree *priv = nft_set_priv(set);
 212         const struct rb_node *parent = priv->root.rb_node;
 213         struct nft_rbtree_elem *rbe, *this = elem->priv;
 214         u8 genmask = nft_genmask_next(net);
 215         int d;
 216
 217         while (parent != NULL) {
 218                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 219
 220                 d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
 221                                            set->klen);
 222                 if (d < 0)
 223                         parent = parent->rb_left;
 224                 else if (d > 0)
 225                         parent = parent->rb_right;
 226                 else {
 227                         if (nft_rbtree_interval_end(rbe) &&
 228                             !nft_rbtree_interval_end(this)) {
 229                                 parent = parent->rb_left;
 230                                 continue;
 231                         } else if (!nft_rbtree_interval_end(rbe) &&
 232                                    nft_rbtree_interval_end(this)) {
 233                                 parent = parent->rb_right;
 234                                 continue;
 235                         } else if (!nft_set_elem_active(&rbe->ext, genmask)) {
 236                                 parent = parent->rb_left;
 237                                 continue;
 238                         }
 239                         nft_rbtree_flush(net, set, rbe);
 240                         return rbe;
 241                 }
 242         }
 243         return NULL;
 244 }
 245
 246 static void nft_rbtree_walk(const struct nft_ctx *ctx,
 247                             struct nft_set *set,
 248                             struct nft_set_iter *iter)
 249 {
 250         struct nft_rbtree *priv = nft_set_priv(set);
 251         struct nft_rbtree_elem *rbe;
 252         struct nft_set_elem elem;
 253         struct rb_node *node;
 254
 255         read_lock_bh(&priv->lock);
 256         for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
 257                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 258
 259                 if (iter->count < iter->skip)
 260                         goto cont;
 261                 if (!nft_set_elem_active(&rbe->ext, iter->genmask))
 262                         goto cont;
 263
 264                 elem.priv = rbe;
 265
 266                 iter->err = iter->fn(ctx, set, iter, &elem);
 267                 if (iter->err < 0) {
 268                         read_unlock_bh(&priv->lock);
 269                         return;
 270                 }
 271 cont:
 272                 iter->count++;
 273         }
 274         read_unlock_bh(&priv->lock);
 275 }
 276
 277 static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[],
 278                                         const struct nft_set_desc *desc)
 279 {
 280         return sizeof(struct nft_rbtree);
 281 }
 282
 283 static int nft_rbtree_init(const struct nft_set *set,
 284                            const struct nft_set_desc *desc,
 285                            const struct nlattr * const nla[])
 286 {
 287         struct nft_rbtree *priv = nft_set_priv(set);
 288
 289         rwlock_init(&priv->lock);
 290         seqcount_init(&priv->count);
 291         priv->root = RB_ROOT;
 292         return 0;
 293 }
 294
 295 static void nft_rbtree_destroy(const struct nft_set *set)
 296 {
 297         struct nft_rbtree *priv = nft_set_priv(set);
 298         struct nft_rbtree_elem *rbe;
 299         struct rb_node *node;
 300
 301         while ((node = priv->root.rb_node) != NULL) {
 302                 rb_erase(node, &priv->root);
 303                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 304                 nft_set_elem_destroy(set, rbe, true);
 305         }
 306 }
 307
 308 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
 309                                 struct nft_set_estimate *est)
 310 {
 311         if (desc->size)
 312                 est->size = sizeof(struct nft_rbtree) +
 313                             desc->size * sizeof(struct nft_rbtree_elem);
 314         else
 315                 est->size = ~0;
 316
 317         est->lookup = NFT_SET_CLASS_O_LOG_N;
 318         est->space  = NFT_SET_CLASS_O_N;
 319
 320         return true;
 321 }
 322
 323 static struct nft_set_type nft_rbtree_type;
 324 static struct nft_set_ops nft_rbtree_ops __read_mostly = {
 325         .type           = &nft_rbtree_type,
 326         .privsize       = nft_rbtree_privsize,
 327         .elemsize       = offsetof(struct nft_rbtree_elem, ext),
 328         .estimate       = nft_rbtree_estimate,
 329         .init           = nft_rbtree_init,
 330         .destroy        = nft_rbtree_destroy,
 331         .insert         = nft_rbtree_insert,
 332         .remove         = nft_rbtree_remove,
 333         .deactivate     = nft_rbtree_deactivate,
 334         .flush          = nft_rbtree_flush,
 335         .activate       = nft_rbtree_activate,
 336         .lookup         = nft_rbtree_lookup,
 337         .walk           = nft_rbtree_walk,
 338         .features       = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT,
 339 };
 340
 341 static struct nft_set_type nft_rbtree_type __read_mostly = {
 342         .ops            = &nft_rbtree_ops,
 343         .owner          = THIS_MODULE,
 344 };
 345
 346 static int __init nft_rbtree_module_init(void)
 347 {
 348         return nft_register_set(&nft_rbtree_type);
 349 }
 350
 351 static void __exit nft_rbtree_module_exit(void)
 352 {
 353         nft_unregister_set(&nft_rbtree_type);
 354 }
 355
 356 module_init(nft_rbtree_module_init);
 357 module_exit(nft_rbtree_module_exit);
 358
 359 MODULE_LICENSE("GPL");
 360 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 361 MODULE_ALIAS_NFT_SET();