![Phil Sutter](/assets/img/avatar_default.png)
Drop nft_set_type's ability to act as a container of multiple backend
implementations it chooses from. Instead consolidate the whole selection
logic in nft_select_set_ops() and the actual backend provided estimate()
callback.
This turns nf_tables_set_types into a list containing all available
backends which is traversed when selecting one matching userspace
requested criteria.
Also, this change allows to embed nft_set_ops structure into
nft_set_type and pull flags field into the latter as it's only used
during selection phase.
A crucial part of this change is to make sure the new layout respects
hash backend constraints formerly enforced by nft_hash_select_ops()
function: This is achieved by introduction of a specific estimate()
callback for nft_hash_fast_ops which returns false for key lengths != 4.
In turn, nft_hash_estimate() is changed to return false for key lengths
== 4 so it won't be chosen by accident. Also, both callbacks must return
false for unbounded sets as their size estimate depends on a known
maximum element count.
Note that this patch partially reverts commit 4f2921ca21
("netfilter:
nf_tables: meter: pick a set backend that supports updates") by making
nft_set_ops_candidate() not explicitly look for an update callback but
make NFT_SET_EVAL a regular backend feature flag which is checked along
with the others. This way all feature requirements are checked in one
go.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
432 lines
11 KiB
C
432 lines
11 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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rwlock_t lock;
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seqcount_t count;
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};
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struct nft_rbtree_elem {
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struct rb_node node;
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struct nft_set_ext ext;
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};
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static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe)
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{
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return nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) &&
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(*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
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}
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static bool nft_rbtree_equal(const struct nft_set *set, const void *this,
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const struct nft_rbtree_elem *interval)
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{
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return memcmp(this, nft_set_ext_key(&interval->ext), set->klen) == 0;
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}
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static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
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const u32 *key, const struct nft_set_ext **ext,
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unsigned int seq)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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const struct nft_rbtree_elem *rbe, *interval = NULL;
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u8 genmask = nft_genmask_cur(net);
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const struct rb_node *parent;
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const void *this;
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int d;
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parent = rcu_dereference_raw(priv->root.rb_node);
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while (parent != NULL) {
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if (read_seqcount_retry(&priv->count, seq))
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return false;
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rbe = rb_entry(parent, struct nft_rbtree_elem, node);
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this = nft_set_ext_key(&rbe->ext);
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d = memcmp(this, key, set->klen);
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if (d < 0) {
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parent = rcu_dereference_raw(parent->rb_left);
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if (interval &&
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nft_rbtree_equal(set, this, interval) &&
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nft_rbtree_interval_end(this) &&
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!nft_rbtree_interval_end(interval))
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continue;
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interval = rbe;
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} else if (d > 0)
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parent = rcu_dereference_raw(parent->rb_right);
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else {
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if (!nft_set_elem_active(&rbe->ext, genmask)) {
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parent = rcu_dereference_raw(parent->rb_left);
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continue;
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}
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if (nft_rbtree_interval_end(rbe))
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goto out;
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*ext = &rbe->ext;
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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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nft_set_elem_active(&interval->ext, genmask) &&
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!nft_rbtree_interval_end(interval)) {
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*ext = &interval->ext;
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return true;
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}
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out:
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return false;
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}
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static bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
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const u32 *key, const struct nft_set_ext **ext)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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unsigned int seq = read_seqcount_begin(&priv->count);
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bool ret;
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ret = __nft_rbtree_lookup(net, set, key, ext, seq);
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if (ret || !read_seqcount_retry(&priv->count, seq))
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return ret;
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read_lock_bh(&priv->lock);
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seq = read_seqcount_begin(&priv->count);
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ret = __nft_rbtree_lookup(net, set, key, ext, seq);
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read_unlock_bh(&priv->lock);
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return ret;
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}
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static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
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const u32 *key, struct nft_rbtree_elem **elem,
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unsigned int seq, unsigned int flags, u8 genmask)
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{
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struct nft_rbtree_elem *rbe, *interval = NULL;
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struct nft_rbtree *priv = nft_set_priv(set);
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const struct rb_node *parent;
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const void *this;
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int d;
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parent = rcu_dereference_raw(priv->root.rb_node);
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while (parent != NULL) {
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if (read_seqcount_retry(&priv->count, seq))
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return false;
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rbe = rb_entry(parent, struct nft_rbtree_elem, node);
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this = nft_set_ext_key(&rbe->ext);
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d = memcmp(this, key, set->klen);
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if (d < 0) {
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parent = rcu_dereference_raw(parent->rb_left);
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interval = rbe;
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} else if (d > 0) {
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parent = rcu_dereference_raw(parent->rb_right);
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} else {
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if (!nft_set_elem_active(&rbe->ext, genmask))
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parent = rcu_dereference_raw(parent->rb_left);
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if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
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(*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
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(flags & NFT_SET_ELEM_INTERVAL_END)) {
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*elem = rbe;
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return true;
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}
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return false;
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}
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}
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if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
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nft_set_elem_active(&interval->ext, genmask) &&
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!nft_rbtree_interval_end(interval)) {
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*elem = interval;
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return true;
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}
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return false;
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}
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static void *nft_rbtree_get(const struct net *net, const struct nft_set *set,
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const struct nft_set_elem *elem, unsigned int flags)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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unsigned int seq = read_seqcount_begin(&priv->count);
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struct nft_rbtree_elem *rbe = ERR_PTR(-ENOENT);
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const u32 *key = (const u32 *)&elem->key.val;
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u8 genmask = nft_genmask_cur(net);
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bool ret;
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ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
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if (ret || !read_seqcount_retry(&priv->count, seq))
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return rbe;
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read_lock_bh(&priv->lock);
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seq = read_seqcount_begin(&priv->count);
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ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
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if (!ret)
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rbe = ERR_PTR(-ENOENT);
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read_unlock_bh(&priv->lock);
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return rbe;
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}
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static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
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struct nft_rbtree_elem *new,
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struct nft_set_ext **ext)
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{
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struct nft_rbtree *priv = nft_set_priv(set);
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u8 genmask = nft_genmask_next(net);
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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 = memcmp(nft_set_ext_key(&rbe->ext),
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nft_set_ext_key(&new->ext),
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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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if (nft_rbtree_interval_end(rbe) &&
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!nft_rbtree_interval_end(new)) {
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p = &parent->rb_left;
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} else if (!nft_rbtree_interval_end(rbe) &&
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nft_rbtree_interval_end(new)) {
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p = &parent->rb_right;
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} else if (nft_set_elem_active(&rbe->ext, genmask)) {
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*ext = &rbe->ext;
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return -EEXIST;
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} else {
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p = &parent->rb_left;
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}
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}
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}
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rb_link_node_rcu(&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 net *net, const struct nft_set *set,
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const struct nft_set_elem *elem,
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struct nft_set_ext **ext)
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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->priv;
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int err;
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write_lock_bh(&priv->lock);
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write_seqcount_begin(&priv->count);
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err = __nft_rbtree_insert(net, set, rbe, ext);
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write_seqcount_end(&priv->count);
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write_unlock_bh(&priv->lock);
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return err;
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}
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static void nft_rbtree_remove(const struct net *net,
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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->priv;
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write_lock_bh(&priv->lock);
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write_seqcount_begin(&priv->count);
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rb_erase(&rbe->node, &priv->root);
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write_seqcount_end(&priv->count);
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write_unlock_bh(&priv->lock);
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}
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static void nft_rbtree_activate(const struct net *net,
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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 = elem->priv;
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nft_set_elem_change_active(net, set, &rbe->ext);
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}
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static bool nft_rbtree_flush(const struct net *net,
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const struct nft_set *set, void *priv)
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{
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struct nft_rbtree_elem *rbe = priv;
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nft_set_elem_change_active(net, set, &rbe->ext);
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return true;
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}
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static void *nft_rbtree_deactivate(const struct net *net,
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const struct nft_set *set,
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const 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, *this = elem->priv;
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u8 genmask = nft_genmask_next(net);
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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 = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
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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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if (!nft_set_elem_active(&rbe->ext, genmask)) {
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parent = parent->rb_left;
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continue;
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}
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if (nft_rbtree_interval_end(rbe) &&
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!nft_rbtree_interval_end(this)) {
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parent = parent->rb_left;
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continue;
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} else if (!nft_rbtree_interval_end(rbe) &&
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nft_rbtree_interval_end(this)) {
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parent = parent->rb_right;
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continue;
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}
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nft_rbtree_flush(net, set, rbe);
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return rbe;
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}
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}
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return NULL;
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}
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static void nft_rbtree_walk(const struct nft_ctx *ctx,
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struct nft_set *set,
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struct nft_set_iter *iter)
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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 nft_set_elem elem;
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struct rb_node *node;
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read_lock_bh(&priv->lock);
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for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
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rbe = rb_entry(node, struct nft_rbtree_elem, node);
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if (iter->count < iter->skip)
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goto cont;
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if (!nft_set_elem_active(&rbe->ext, iter->genmask))
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goto cont;
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elem.priv = rbe;
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iter->err = iter->fn(ctx, set, iter, &elem);
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if (iter->err < 0) {
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read_unlock_bh(&priv->lock);
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return;
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}
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cont:
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iter->count++;
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}
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read_unlock_bh(&priv->lock);
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}
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static unsigned int nft_rbtree_privsize(const struct nlattr * const nla[],
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const struct nft_set_desc *desc)
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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 nft_set_desc *desc,
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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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rwlock_init(&priv->lock);
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seqcount_init(&priv->count);
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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_set_elem_destroy(set, rbe, true);
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}
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}
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static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
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struct nft_set_estimate *est)
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{
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if (desc->size)
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est->size = sizeof(struct nft_rbtree) +
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desc->size * sizeof(struct nft_rbtree_elem);
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else
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est->size = ~0;
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est->lookup = NFT_SET_CLASS_O_LOG_N;
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est->space = NFT_SET_CLASS_O_N;
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return true;
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}
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static struct nft_set_type nft_rbtree_type __read_mostly = {
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.owner = THIS_MODULE,
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.features = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT,
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.ops = {
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.privsize = nft_rbtree_privsize,
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.elemsize = offsetof(struct nft_rbtree_elem, ext),
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.estimate = nft_rbtree_estimate,
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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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.deactivate = nft_rbtree_deactivate,
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.flush = nft_rbtree_flush,
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.activate = nft_rbtree_activate,
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.lookup = nft_rbtree_lookup,
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.walk = nft_rbtree_walk,
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.get = nft_rbtree_get,
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},
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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_type);
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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_type);
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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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