net/netfilter/nft_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_lookup(const struct nft_set *set, const u32 *key,
  39                               const struct nft_set_ext **ext)
  40 {
  41         const struct nft_rbtree *priv = nft_set_priv(set);
  42         const struct nft_rbtree_elem *rbe, *interval = NULL;
  43         const struct rb_node *parent;
  44         u8 genmask = nft_genmask_cur(read_pnet(&set->pnet));
  45         int d;
  46
  47         spin_lock_bh(&nft_rbtree_lock);
  48         parent = priv->root.rb_node;
  49         while (parent != NULL) {
  50                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
  51
  52                 d = memcmp(nft_set_ext_key(&rbe->ext), key, set->klen);
  53                 if (d < 0) {
  54                         parent = parent->rb_left;
  55                         interval = rbe;
  56                 } else if (d > 0)
  57                         parent = parent->rb_right;
  58                 else {
  59 found:
  60                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
  61                                 parent = parent->rb_left;
  62                                 continue;
  63                         }
  64                         if (nft_rbtree_interval_end(rbe))
  65                                 goto out;
  66                         spin_unlock_bh(&nft_rbtree_lock);
  67
  68                         *ext = &rbe->ext;
  69                         return true;
  70                 }
  71         }
  72
  73         if (set->flags & NFT_SET_INTERVAL && interval != NULL) {
  74                 rbe = interval;
  75                 goto found;
  76         }
  77 out:
  78         spin_unlock_bh(&nft_rbtree_lock);
  79         return false;
  80 }
  81
  82 static int __nft_rbtree_insert(const struct nft_set *set,
  83                                struct nft_rbtree_elem *new)
  84 {
  85         struct nft_rbtree *priv = nft_set_priv(set);
  86         struct nft_rbtree_elem *rbe;
  87         struct rb_node *parent, **p;
  88         u8 genmask = nft_genmask_next(read_pnet(&set->pnet));
  89         int d;
  90
  91         parent = NULL;
  92         p = &priv->root.rb_node;
  93         while (*p != NULL) {
  94                 parent = *p;
  95                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
  96                 d = memcmp(nft_set_ext_key(&rbe->ext),
  97                            nft_set_ext_key(&new->ext),
  98                            set->klen);
  99                 if (d < 0)
 100                         p = &parent->rb_left;
 101                 else if (d > 0)
 102                         p = &parent->rb_right;
 103                 else {
 104                         if (nft_set_elem_active(&rbe->ext, genmask))
 105                                 return -EEXIST;
 106                         p = &parent->rb_left;
 107                 }
 108         }
 109         rb_link_node(&new->node, parent, p);
 110         rb_insert_color(&new->node, &priv->root);
 111         return 0;
 112 }
 113
 114 static int nft_rbtree_insert(const struct nft_set *set,
 115                              const struct nft_set_elem *elem)
 116 {
 117         struct nft_rbtree_elem *rbe = elem->priv;
 118         int err;
 119
 120         spin_lock_bh(&nft_rbtree_lock);
 121         err = __nft_rbtree_insert(set, rbe);
 122         spin_unlock_bh(&nft_rbtree_lock);
 123
 124         return err;
 125 }
 126
 127 static void nft_rbtree_remove(const struct nft_set *set,
 128                               const struct nft_set_elem *elem)
 129 {
 130         struct nft_rbtree *priv = nft_set_priv(set);
 131         struct nft_rbtree_elem *rbe = elem->priv;
 132
 133         spin_lock_bh(&nft_rbtree_lock);
 134         rb_erase(&rbe->node, &priv->root);
 135         spin_unlock_bh(&nft_rbtree_lock);
 136 }
 137
 138 static void nft_rbtree_activate(const struct nft_set *set,
 139                                 const struct nft_set_elem *elem)
 140 {
 141         struct nft_rbtree_elem *rbe = elem->priv;
 142
 143         nft_set_elem_change_active(set, &rbe->ext);
 144 }
 145
 146 static void *nft_rbtree_deactivate(const struct nft_set *set,
 147                                    const struct nft_set_elem *elem)
 148 {
 149         const struct nft_rbtree *priv = nft_set_priv(set);
 150         const struct rb_node *parent = priv->root.rb_node;
 151         struct nft_rbtree_elem *rbe;
 152         u8 genmask = nft_genmask_cur(read_pnet(&set->pnet));
 153         int d;
 154
 155         while (parent != NULL) {
 156                 rbe = rb_entry(parent, struct nft_rbtree_elem, node);
 157
 158                 d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
 159                                            set->klen);
 160                 if (d < 0)
 161                         parent = parent->rb_left;
 162                 else if (d > 0)
 163                         parent = parent->rb_right;
 164                 else {
 165                         if (!nft_set_elem_active(&rbe->ext, genmask)) {
 166                                 parent = parent->rb_left;
 167                                 continue;
 168                         }
 169                         nft_set_elem_change_active(set, &rbe->ext);
 170                         return rbe;
 171                 }
 172         }
 173         return NULL;
 174 }
 175
 176 static void nft_rbtree_walk(const struct nft_ctx *ctx,
 177                             const struct nft_set *set,
 178                             struct nft_set_iter *iter)
 179 {
 180         const struct nft_rbtree *priv = nft_set_priv(set);
 181         struct nft_rbtree_elem *rbe;
 182         struct nft_set_elem elem;
 183         struct rb_node *node;
 184         u8 genmask = nft_genmask_cur(read_pnet(&set->pnet));
 185
 186         spin_lock_bh(&nft_rbtree_lock);
 187         for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
 188                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 189
 190                 if (iter->count < iter->skip)
 191                         goto cont;
 192                 if (!nft_set_elem_active(&rbe->ext, genmask))
 193                         goto cont;
 194
 195                 elem.priv = rbe;
 196
 197                 iter->err = iter->fn(ctx, set, iter, &elem);
 198                 if (iter->err < 0) {
 199                         spin_unlock_bh(&nft_rbtree_lock);
 200                         return;
 201                 }
 202 cont:
 203                 iter->count++;
 204         }
 205         spin_unlock_bh(&nft_rbtree_lock);
 206 }
 207
 208 static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[])
 209 {
 210         return sizeof(struct nft_rbtree);
 211 }
 212
 213 static int nft_rbtree_init(const struct nft_set *set,
 214                            const struct nft_set_desc *desc,
 215                            const struct nlattr * const nla[])
 216 {
 217         struct nft_rbtree *priv = nft_set_priv(set);
 218
 219         priv->root = RB_ROOT;
 220         return 0;
 221 }
 222
 223 static void nft_rbtree_destroy(const struct nft_set *set)
 224 {
 225         struct nft_rbtree *priv = nft_set_priv(set);
 226         struct nft_rbtree_elem *rbe;
 227         struct rb_node *node;
 228
 229         while ((node = priv->root.rb_node) != NULL) {
 230                 rb_erase(node, &priv->root);
 231                 rbe = rb_entry(node, struct nft_rbtree_elem, node);
 232                 nft_set_elem_destroy(set, rbe);
 233         }
 234 }
 235
 236 static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
 237                                 struct nft_set_estimate *est)
 238 {
 239         unsigned int nsize;
 240
 241         nsize = sizeof(struct nft_rbtree_elem);
 242         if (desc->size)
 243                 est->size = sizeof(struct nft_rbtree) + desc->size * nsize;
 244         else
 245                 est->size = nsize;
 246
 247         est->class = NFT_SET_CLASS_O_LOG_N;
 248
 249         return true;
 250 }
 251
 252 static struct nft_set_ops nft_rbtree_ops __read_mostly = {
 253         .privsize       = nft_rbtree_privsize,
 254         .elemsize       = offsetof(struct nft_rbtree_elem, ext),
 255         .estimate       = nft_rbtree_estimate,
 256         .init           = nft_rbtree_init,
 257         .destroy        = nft_rbtree_destroy,
 258         .insert         = nft_rbtree_insert,
 259         .remove         = nft_rbtree_remove,
 260         .deactivate     = nft_rbtree_deactivate,
 261         .activate       = nft_rbtree_activate,
 262         .lookup         = nft_rbtree_lookup,
 263         .walk           = nft_rbtree_walk,
 264         .features       = NFT_SET_INTERVAL | NFT_SET_MAP,
 265         .owner          = THIS_MODULE,
 266 };
 267
 268 static int __init nft_rbtree_module_init(void)
 269 {
 270         return nft_register_set(&nft_rbtree_ops);
 271 }
 272
 273 static void __exit nft_rbtree_module_exit(void)
 274 {
 275         nft_unregister_set(&nft_rbtree_ops);
 276 }
 277
 278 module_init(nft_rbtree_module_init);
 279 module_exit(nft_rbtree_module_exit);
 280
 281 MODULE_LICENSE("GPL");
 282 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 283 MODULE_ALIAS_NFT_SET();