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 nft_set *set,
 155                               const struct nft_set_elem *elem)
 156 {
 157         struct nft_rbtree *priv = nft_set_priv(set);
 158         struct nft_rbtree_elem *rbe = elem->priv;
 159
 160         spin_lock_bh(&nft_rbtree_lock);
 161         rb_erase(&rbe->node, &priv->root);
 162         spin_unlock_bh(&nft_rbtree_lock);
 163 }
 164
 165 static void nft_rbtree_activate(const struct net *net,
 166                                 const struct nft_set *set,
 167                                 const struct nft_set_elem *elem)
 168 {
 169         struct nft_rbtree_elem *rbe = elem->priv;
 170
 171         nft_set_elem_change_active(net, set, &rbe->ext);
 172 }
 173
 174 static void *nft_rbtree_deactivate(const struct net *net,
 175                                    const struct nft_set *set,
 176                                    const struct nft_set_elem *elem)
 177 {
 178         const struct nft_rbtree *priv = nft_set_priv(set);
 179         const struct rb_node *parent = priv->root.rb_node;
 180         struct nft_rbtree_elem *rbe, *this = elem->priv;
 181         u8 genmask = nft_genmask_next(net);
 182         int d;
 183
 184         while (parent != NULL) {
 185                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 186
 187                 d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
 188                                            set->klen);
 189                 if (d < 0)
 190                         parent = parent->rb_left;
 191                 else if (d > 0)
 192                         parent = parent->rb_right;
 193                 else {
 194                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
 195                                 parent = parent->rb_left;
 196                                 continue;
 197                         }
 198                         if (nft_rbtree_interval_end(rbe) &&
 199                             !nft_rbtree_interval_end(this)) {
 200                                 parent = parent->rb_left;
 201                                 continue;
 202                         } else if (!nft_rbtree_interval_end(rbe) &&
 203                                    nft_rbtree_interval_end(this)) {
 204                                 parent = parent->rb_right;
 205                                 continue;
 206                         }
 207                         nft_set_elem_change_active(net, set, &rbe->ext);
 208                         return rbe;
 209                 }
 210         }
 211         return NULL;
 212 }
 213
 214 static void nft_rbtree_walk(const struct nft_ctx *ctx,
 215                             const struct nft_set *set,
 216                             struct nft_set_iter *iter)
 217 {
 218         const struct nft_rbtree *priv = nft_set_priv(set);
 219         struct nft_rbtree_elem *rbe;
 220         struct nft_set_elem elem;
 221         struct rb_node *node;
 222
 223         spin_lock_bh(&nft_rbtree_lock);
 224         for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
 225                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 226
 227                 if (iter->count < iter->skip)
 228                         goto cont;
 229                 if (!nft_set_elem_active(&rbe->ext, iter->genmask))
 230                         goto cont;
 231
 232                 elem.priv = rbe;
 233
 234                 iter->err = iter->fn(ctx, set, iter, &elem);
 235                 if (iter->err < 0) {
 236                         spin_unlock_bh(&nft_rbtree_lock);
 237                         return;
 238                 }
 239 cont:
 240                 iter->count++;
 241         }
 242         spin_unlock_bh(&nft_rbtree_lock);
 243 }
 244
 245 static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[])
 246 {
 247         return sizeof(struct nft_rbtree);
 248 }
 249
 250 static int nft_rbtree_init(const struct nft_set *set,
 251                            const struct nft_set_desc *desc,
 252                            const struct nlattr * const nla[])
 253 {
 254         struct nft_rbtree *priv = nft_set_priv(set);
 255
 256         priv->root = RB_ROOT;
 257         return 0;
 258 }
 259
 260 static void nft_rbtree_destroy(const struct nft_set *set)
 261 {
 262         struct nft_rbtree *priv = nft_set_priv(set);
 263         struct nft_rbtree_elem *rbe;
 264         struct rb_node *node;
 265
 266         while ((node = priv->root.rb_node) != NULL) {
 267                 rb_erase(node, &priv->root);
 268                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 269                 nft_set_elem_destroy(set, rbe);
 270         }
 271 }
 272
 273 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
 274                                 struct nft_set_estimate *est)
 275 {
 276         unsigned int nsize;
 277
 278         nsize = sizeof(struct nft_rbtree_elem);
 279         if (desc->size)
 280                 est->size = sizeof(struct nft_rbtree) + desc->size * nsize;
 281         else
 282                 est->size = nsize;
 283
 284         est->class = NFT_SET_CLASS_O_LOG_N;
 285
 286         return true;
 287 }
 288
 289 static struct nft_set_ops nft_rbtree_ops __read_mostly = {
 290         .privsize       = nft_rbtree_privsize,
 291         .elemsize       = offsetof(struct nft_rbtree_elem, ext),
 292         .estimate       = nft_rbtree_estimate,
 293         .init           = nft_rbtree_init,
 294         .destroy        = nft_rbtree_destroy,
 295         .insert         = nft_rbtree_insert,
 296         .remove         = nft_rbtree_remove,
 297         .deactivate     = nft_rbtree_deactivate,
 298         .activate       = nft_rbtree_activate,
 299         .lookup         = nft_rbtree_lookup,
 300         .walk           = nft_rbtree_walk,
 301         .features       = NFT_SET_INTERVAL | NFT_SET_MAP,
 302         .owner          = THIS_MODULE,
 303 };
 304
 305 static int __init nft_rbtree_module_init(void)
 306 {
 307         return nft_register_set(&nft_rbtree_ops);
 308 }
 309
 310 static void __exit nft_rbtree_module_exit(void)
 311 {
 312         nft_unregister_set(&nft_rbtree_ops);
 313 }
 314
 315 module_init(nft_rbtree_module_init);
 316 module_exit(nft_rbtree_module_exit);
 317
 318 MODULE_LICENSE("GPL");
 319 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 320 MODULE_ALIAS_NFT_SET();