2fb91ddbf8
This patch fixes several things which related to the handling of end interval elements: * Chain use underflow with intervals and map: If you add a rule using intervals+map that introduces a loop, the error path of the rbtree set decrements the chain refcount for each side of the interval, leading to a chain use counter underflow. * Don't copy the data part of the end interval element since, this area is uninitialized and this confuses the loop detection code. * Don't allocate room for the data part of end interval elements since this is unused. So, after this patch the idea is that end interval elements don't have a data part. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: Patrick McHardy <kaber@trash.net>
254 lines
6.0 KiB
C
254 lines
6.0 KiB
C
/*
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* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Development of this code funded by Astaro AG (http://www.astaro.com/)
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_tables.h>
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struct nft_rbtree {
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struct rb_root root;
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};
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struct nft_rbtree_elem {
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struct rb_node node;
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u16 flags;
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struct nft_data key;
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struct nft_data data[];
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};
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static bool nft_rbtree_lookup(const struct nft_set *set,
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const struct nft_data *key,
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struct nft_data *data)
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{
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const struct nft_rbtree *priv = nft_set_priv(set);
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const struct nft_rbtree_elem *rbe, *interval = NULL;
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const struct rb_node *parent = priv->root.rb_node;
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int d;
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while (parent != NULL) {
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rbe = rb_entry(parent, struct nft_rbtree_elem, node);
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d = nft_data_cmp(&rbe->key, key, set->klen);
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if (d < 0) {
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parent = parent->rb_left;
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interval = rbe;
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} else if (d > 0)
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parent = parent->rb_right;
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else {
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found:
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if (rbe->flags & NFT_SET_ELEM_INTERVAL_END)
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goto out;
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if (set->flags & NFT_SET_MAP)
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nft_data_copy(data, rbe->data);
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return true;
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}
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}
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if (set->flags & NFT_SET_INTERVAL && interval != NULL) {
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rbe = interval;
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goto found;
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}
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out:
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return false;
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}
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static void nft_rbtree_elem_destroy(const struct nft_set *set,
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struct nft_rbtree_elem *rbe)
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{
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nft_data_uninit(&rbe->key, NFT_DATA_VALUE);
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if (set->flags & NFT_SET_MAP &&
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!(rbe->flags & NFT_SET_ELEM_INTERVAL_END))
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nft_data_uninit(rbe->data, set->dtype);
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kfree(rbe);
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}
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static int __nft_rbtree_insert(const struct nft_set *set,
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struct nft_rbtree_elem *new)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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struct nft_rbtree_elem *rbe;
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struct rb_node *parent, **p;
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int d;
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parent = NULL;
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p = &priv->root.rb_node;
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while (*p != NULL) {
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parent = *p;
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rbe = rb_entry(parent, struct nft_rbtree_elem, node);
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d = nft_data_cmp(&rbe->key, &new->key, set->klen);
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if (d < 0)
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p = &parent->rb_left;
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else if (d > 0)
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p = &parent->rb_right;
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else
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return -EEXIST;
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}
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rb_link_node(&new->node, parent, p);
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rb_insert_color(&new->node, &priv->root);
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return 0;
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}
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static int nft_rbtree_insert(const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_rbtree_elem *rbe;
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unsigned int size;
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int err;
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size = sizeof(*rbe);
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if (set->flags & NFT_SET_MAP &&
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!(elem->flags & NFT_SET_ELEM_INTERVAL_END))
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size += sizeof(rbe->data[0]);
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rbe = kzalloc(size, GFP_KERNEL);
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if (rbe == NULL)
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return -ENOMEM;
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rbe->flags = elem->flags;
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nft_data_copy(&rbe->key, &elem->key);
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if (set->flags & NFT_SET_MAP &&
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!(rbe->flags & NFT_SET_ELEM_INTERVAL_END))
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nft_data_copy(rbe->data, &elem->data);
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err = __nft_rbtree_insert(set, rbe);
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if (err < 0)
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kfree(rbe);
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return err;
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}
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static void nft_rbtree_remove(const struct nft_set *set,
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const struct nft_set_elem *elem)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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struct nft_rbtree_elem *rbe = elem->cookie;
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rb_erase(&rbe->node, &priv->root);
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kfree(rbe);
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}
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static int nft_rbtree_get(const struct nft_set *set, struct nft_set_elem *elem)
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{
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const struct nft_rbtree *priv = nft_set_priv(set);
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const struct rb_node *parent = priv->root.rb_node;
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struct nft_rbtree_elem *rbe;
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int d;
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while (parent != NULL) {
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rbe = rb_entry(parent, struct nft_rbtree_elem, node);
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d = nft_data_cmp(&rbe->key, &elem->key, set->klen);
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if (d < 0)
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parent = parent->rb_left;
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else if (d > 0)
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parent = parent->rb_right;
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else {
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elem->cookie = rbe;
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if (set->flags & NFT_SET_MAP &&
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!(rbe->flags & NFT_SET_ELEM_INTERVAL_END))
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nft_data_copy(&elem->data, rbe->data);
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elem->flags = rbe->flags;
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return 0;
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}
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}
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return -ENOENT;
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}
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static void nft_rbtree_walk(const struct nft_ctx *ctx,
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const struct nft_set *set,
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struct nft_set_iter *iter)
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{
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const struct nft_rbtree *priv = nft_set_priv(set);
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const struct nft_rbtree_elem *rbe;
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struct nft_set_elem elem;
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struct rb_node *node;
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for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
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if (iter->count < iter->skip)
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goto cont;
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rbe = rb_entry(node, struct nft_rbtree_elem, node);
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nft_data_copy(&elem.key, &rbe->key);
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if (set->flags & NFT_SET_MAP &&
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!(rbe->flags & NFT_SET_ELEM_INTERVAL_END))
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nft_data_copy(&elem.data, rbe->data);
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elem.flags = rbe->flags;
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iter->err = iter->fn(ctx, set, iter, &elem);
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if (iter->err < 0)
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return;
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cont:
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iter->count++;
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}
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}
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static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[])
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{
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return sizeof(struct nft_rbtree);
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}
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static int nft_rbtree_init(const struct nft_set *set,
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const struct nlattr * const nla[])
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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priv->root = RB_ROOT;
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return 0;
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}
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static void nft_rbtree_destroy(const struct nft_set *set)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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struct nft_rbtree_elem *rbe;
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struct rb_node *node;
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while ((node = priv->root.rb_node) != NULL) {
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rb_erase(node, &priv->root);
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rbe = rb_entry(node, struct nft_rbtree_elem, node);
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nft_rbtree_elem_destroy(set, rbe);
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}
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}
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static struct nft_set_ops nft_rbtree_ops __read_mostly = {
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.privsize = nft_rbtree_privsize,
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.init = nft_rbtree_init,
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.destroy = nft_rbtree_destroy,
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.insert = nft_rbtree_insert,
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.remove = nft_rbtree_remove,
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.get = nft_rbtree_get,
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.lookup = nft_rbtree_lookup,
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.walk = nft_rbtree_walk,
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.features = NFT_SET_INTERVAL | NFT_SET_MAP,
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.owner = THIS_MODULE,
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};
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static int __init nft_rbtree_module_init(void)
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{
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return nft_register_set(&nft_rbtree_ops);
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}
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static void __exit nft_rbtree_module_exit(void)
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{
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nft_unregister_set(&nft_rbtree_ops);
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}
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module_init(nft_rbtree_module_init);
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module_exit(nft_rbtree_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_ALIAS_NFT_SET();
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