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 static DEFINE_SPINLOCK(nft_rbtree_lock);
  22
  23 struct nft_rbtree {
  24         struct rb_root          root;
  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 {
  47         const struct nft_rbtree *priv = nft_set_priv(set);
  48         const struct nft_rbtree_elem *rbe, *interval = NULL;
  49         u8 genmask = nft_genmask_cur(net);
  50         const struct rb_node *parent;
  51         const void *this;
  52         int d;
  53
  54         spin_lock_bh(&nft_rbtree_lock);
  55         parent = priv->root.rb_node;
  56         while (parent != NULL) {
  57                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
  58
  59                 this = nft_set_ext_key(&rbe->ext);
  60                 d = memcmp(this, key, set->klen);
  61                 if (d < 0) {
  62                         parent = parent->rb_left;
  63                         /* In case of adjacent ranges, we always see the high
  64                          * part of the range in first place, before the low one.
  65                          * So don't update interval if the keys are equal.
  66                          */
  67                         if (interval && nft_rbtree_equal(set, this, interval))
  68                                 continue;
  69                         interval = rbe;
  70                 } else if (d > 0)
  71                         parent = parent->rb_right;
  72                 else {
  73                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
  74                                 parent = parent->rb_left;
  75                                 continue;
  76                         }
  77                         if (nft_rbtree_interval_end(rbe))
  78                                 goto out;
  79                         spin_unlock_bh(&nft_rbtree_lock);
  80
  81                         *ext = &rbe->ext;
  82                         return true;
  83                 }
  84         }
  85
  86         if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
  87             nft_set_elem_active(&interval->ext, genmask) &&
  88             !nft_rbtree_interval_end(interval)) {
  89                 spin_unlock_bh(&nft_rbtree_lock);
  90                 *ext = &interval->ext;
  91                 return true;
  92         }
  93 out:
  94         spin_unlock_bh(&nft_rbtree_lock);
  95         return false;
  96 }
  97
  98 static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
  99                                struct nft_rbtree_elem *new,
 100                                struct nft_set_ext **ext)
 101 {
 102         struct nft_rbtree *priv = nft_set_priv(set);
 103         u8 genmask = nft_genmask_next(net);
 104         struct nft_rbtree_elem *rbe;
 105         struct rb_node *parent, **p;
 106         int d;
 107
 108         parent = NULL;
 109         p = &priv->root.rb_node;
 110         while (*p != NULL) {
 111                 parent = *p;
 112                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 113                 d = memcmp(nft_set_ext_key(&rbe->ext),
 114                            nft_set_ext_key(&new->ext),
 115                            set->klen);
 116                 if (d < 0)
 117                         p = &parent->rb_left;
 118                 else if (d > 0)
 119                         p = &parent->rb_right;
 120                 else {
 121                         if (nft_set_elem_active(&rbe->ext, genmask)) {
 122                                 if (nft_rbtree_interval_end(rbe) &&
 123                                     !nft_rbtree_interval_end(new))
 124                                         p = &parent->rb_left;
 125                                 else if (!nft_rbtree_interval_end(rbe) &&
 126                                          nft_rbtree_interval_end(new))
 127                                         p = &parent->rb_right;
 128                                 else {
 129                                         *ext = &rbe->ext;
 130                                         return -EEXIST;
 131                                 }
 132                         }
 133                 }
 134         }
 135         rb_link_node(&new->node, parent, p);
 136         rb_insert_color(&new->node, &priv->root);
 137         return 0;
 138 }
 139
 140 static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
 141                              const struct nft_set_elem *elem,
 142                              struct nft_set_ext **ext)
 143 {
 144         struct nft_rbtree_elem *rbe = elem->priv;
 145         int err;
 146
 147         spin_lock_bh(&nft_rbtree_lock);
 148         err = __nft_rbtree_insert(net, set, rbe, ext);
 149         spin_unlock_bh(&nft_rbtree_lock);
 150
 151         return err;
 152 }
 153
 154 static void nft_rbtree_remove(const struct net *net,
 155                               const struct nft_set *set,
 156                               const struct nft_set_elem *elem)
 157 {
 158         struct nft_rbtree *priv = nft_set_priv(set);
 159         struct nft_rbtree_elem *rbe = elem->priv;
 160
 161         spin_lock_bh(&nft_rbtree_lock);
 162         rb_erase(&rbe->node, &priv->root);
 163         spin_unlock_bh(&nft_rbtree_lock);
 164 }
 165
 166 static void nft_rbtree_activate(const struct net *net,
 167                                 const struct nft_set *set,
 168                                 const struct nft_set_elem *elem)
 169 {
 170         struct nft_rbtree_elem *rbe = elem->priv;
 171
 172         nft_set_elem_change_active(net, set, &rbe->ext);
 173 }
 174
 175 static bool nft_rbtree_deactivate_one(const struct net *net,
 176                                       const struct nft_set *set, void *priv)
 177 {
 178         struct nft_rbtree_elem *rbe = priv;
 179
 180         nft_set_elem_change_active(net, set, &rbe->ext);
 181         return true;
 182 }
 183
 184 static void *nft_rbtree_deactivate(const struct net *net,
 185                                    const struct nft_set *set,
 186                                    const struct nft_set_elem *elem)
 187 {
 188         const struct nft_rbtree *priv = nft_set_priv(set);
 189         const struct rb_node *parent = priv->root.rb_node;
 190         struct nft_rbtree_elem *rbe, *this = elem->priv;
 191         u8 genmask = nft_genmask_next(net);
 192         int d;
 193
 194         while (parent != NULL) {
 195                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 196
 197                 d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
 198                                            set->klen);
 199                 if (d < 0)
 200                         parent = parent->rb_left;
 201                 else if (d > 0)
 202                         parent = parent->rb_right;
 203                 else {
 204                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
 205                                 parent = parent->rb_left;
 206                                 continue;
 207                         }
 208                         if (nft_rbtree_interval_end(rbe) &&
 209                             !nft_rbtree_interval_end(this)) {
 210                                 parent = parent->rb_left;
 211                                 continue;
 212                         } else if (!nft_rbtree_interval_end(rbe) &&
 213                                    nft_rbtree_interval_end(this)) {
 214                                 parent = parent->rb_right;
 215                                 continue;
 216                         }
 217                         nft_rbtree_deactivate_one(net, set, rbe);
 218                         return rbe;
 219                 }
 220         }
 221         return NULL;
 222 }
 223
 224 static void nft_rbtree_walk(const struct nft_ctx *ctx,
 225                             struct nft_set *set,
 226                             struct nft_set_iter *iter)
 227 {
 228         const struct nft_rbtree *priv = nft_set_priv(set);
 229         struct nft_rbtree_elem *rbe;
 230         struct nft_set_elem elem;
 231         struct rb_node *node;
 232
 233         spin_lock_bh(&nft_rbtree_lock);
 234         for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
 235                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 236
 237                 if (iter->count < iter->skip)
 238                         goto cont;
 239                 if (!nft_set_elem_active(&rbe->ext, iter->genmask))
 240                         goto cont;
 241
 242                 elem.priv = rbe;
 243
 244                 iter->err = iter->fn(ctx, set, iter, &elem);
 245                 if (iter->err < 0) {
 246                         spin_unlock_bh(&nft_rbtree_lock);
 247                         return;
 248                 }
 249 cont:
 250                 iter->count++;
 251         }
 252         spin_unlock_bh(&nft_rbtree_lock);
 253 }
 254
 255 static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[])
 256 {
 257         return sizeof(struct nft_rbtree);
 258 }
 259
 260 static int nft_rbtree_init(const struct nft_set *set,
 261                            const struct nft_set_desc *desc,
 262                            const struct nlattr * const nla[])
 263 {
 264         struct nft_rbtree *priv = nft_set_priv(set);
 265
 266         priv->root = RB_ROOT;
 267         return 0;
 268 }
 269
 270 static void nft_rbtree_destroy(const struct nft_set *set)
 271 {
 272         struct nft_rbtree *priv = nft_set_priv(set);
 273         struct nft_rbtree_elem *rbe;
 274         struct rb_node *node;
 275
 276         while ((node = priv->root.rb_node) != NULL) {
 277                 rb_erase(node, &priv->root);
 278                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 279                 nft_set_elem_destroy(set, rbe, true);
 280         }
 281 }
 282
 283 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
 284                                 struct nft_set_estimate *est)
 285 {
 286         unsigned int nsize;
 287
 288         nsize = sizeof(struct nft_rbtree_elem);
 289         if (desc->size)
 290                 est->size = sizeof(struct nft_rbtree) + desc->size * nsize;
 291         else
 292                 est->size = nsize;
 293
 294         est->class = NFT_SET_CLASS_O_LOG_N;
 295
 296         return true;
 297 }
 298
 299 static struct nft_set_ops nft_rbtree_ops __read_mostly = {
 300         .privsize       = nft_rbtree_privsize,
 301         .elemsize       = offsetof(struct nft_rbtree_elem, ext),
 302         .estimate       = nft_rbtree_estimate,
 303         .init           = nft_rbtree_init,
 304         .destroy        = nft_rbtree_destroy,
 305         .insert         = nft_rbtree_insert,
 306         .remove         = nft_rbtree_remove,
 307         .deactivate     = nft_rbtree_deactivate,
 308         .deactivate_one = nft_rbtree_deactivate_one,
 309         .activate       = nft_rbtree_activate,
 310         .lookup         = nft_rbtree_lookup,
 311         .walk           = nft_rbtree_walk,
 312         .features       = NFT_SET_INTERVAL | NFT_SET_MAP,
 313         .owner          = THIS_MODULE,
 314 };
 315
 316 static int __init nft_rbtree_module_init(void)
 317 {
 318         return nft_register_set(&nft_rbtree_ops);
 319 }
 320
 321 static void __exit nft_rbtree_module_exit(void)
 322 {
 323         nft_unregister_set(&nft_rbtree_ops);
 324 }
 325
 326 module_init(nft_rbtree_module_init);
 327 module_exit(nft_rbtree_module_exit);
 328
 329 MODULE_LICENSE("GPL");
 330 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 331 MODULE_ALIAS_NFT_SET();