// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <[email protected]>
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
struct nft_rbtree {
struct rb_root root;
rwlock_t lock;
seqcount_rwlock_t count;
unsigned long last_gc;
};
struct nft_rbtree_elem {
struct nft_elem_priv priv;
struct rb_node node;
struct nft_set_ext ext;
};
static bool nft_rbtree_interval_end(const struct nft_rbtree_elem *rbe)
{
return nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) &&
(*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END);
}
static bool nft_rbtree_interval_start(const struct nft_rbtree_elem *rbe)
{
return !nft_rbtree_interval_end(rbe);
}
static int nft_rbtree_cmp(const struct nft_set *set,
const struct nft_rbtree_elem *e1,
const struct nft_rbtree_elem *e2)
{
return memcmp(nft_set_ext_key(&e1->ext), nft_set_ext_key(&e2->ext),
set->klen);
}
static bool nft_rbtree_elem_expired(const struct nft_rbtree_elem *rbe)
{
return nft_set_elem_expired(&rbe->ext);
}
static bool __nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
const u32 *key, const struct nft_set_ext **ext,
unsigned int seq)
{
struct nft_rbtree *priv = nft_set_priv(set);
const struct nft_rbtree_elem *rbe, *interval = NULL;
u8 genmask = nft_genmask_cur(net);
const struct rb_node *parent;
int d;
parent = rcu_dereference_raw(priv->root.rb_node);
while (parent != NULL) {
if (read_seqcount_retry(&priv->count, seq))
return false;
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
d = memcmp(nft_set_ext_key(&rbe->ext), key, set->klen);
if (d < 0) {
parent = rcu_dereference_raw(parent->rb_left);
if (interval &&
!nft_rbtree_cmp(set, rbe, interval) &&
nft_rbtree_interval_end(rbe) &&
nft_rbtree_interval_start(interval))
continue;
interval = rbe;
} else if (d > 0)
parent = rcu_dereference_raw(parent->rb_right);
else {
if (!nft_set_elem_active(&rbe->ext, genmask)) {
parent = rcu_dereference_raw(parent->rb_left);
continue;
}
if (nft_rbtree_elem_expired(rbe))
return false;
if (nft_rbtree_interval_end(rbe)) {
if (nft_set_is_anonymous(set))
return false;
parent = rcu_dereference_raw(parent->rb_left);
interval = NULL;
continue;
}
*ext = &rbe->ext;
return true;
}
}
if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
nft_set_elem_active(&interval->ext, genmask) &&
!nft_rbtree_elem_expired(interval) &&
nft_rbtree_interval_start(interval)) {
*ext = &interval->ext;
return true;
}
return false;
}
INDIRECT_CALLABLE_SCOPE
bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
const u32 *key, const struct nft_set_ext **ext)
{
struct nft_rbtree *priv = nft_set_priv(set);
unsigned int seq = read_seqcount_begin(&priv->count);
bool ret;
ret = __nft_rbtree_lookup(net, set, key, ext, seq);
if (ret || !read_seqcount_retry(&priv->count, seq))
return ret;
read_lock_bh(&priv->lock);
seq = read_seqcount_begin(&priv->count);
ret = __nft_rbtree_lookup(net, set, key, ext, seq);
read_unlock_bh(&priv->lock);
return ret;
}
static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
const u32 *key, struct nft_rbtree_elem **elem,
unsigned int seq, unsigned int flags, u8 genmask)
{
struct nft_rbtree_elem *rbe, *interval = NULL;
struct nft_rbtree *priv = nft_set_priv(set);
const struct rb_node *parent;
const void *this;
int d;
parent = rcu_dereference_raw(priv->root.rb_node);
while (parent != NULL) {
if (read_seqcount_retry(&priv->count, seq))
return false;
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
this = nft_set_ext_key(&rbe->ext);
d = memcmp(this, key, set->klen);
if (d < 0) {
parent = rcu_dereference_raw(parent->rb_left);
if (!(flags & NFT_SET_ELEM_INTERVAL_END))
interval = rbe;
} else if (d > 0) {
parent = rcu_dereference_raw(parent->rb_right);
if (flags & NFT_SET_ELEM_INTERVAL_END)
interval = rbe;
} else {
if (!nft_set_elem_active(&rbe->ext, genmask)) {
parent = rcu_dereference_raw(parent->rb_left);
continue;
}
if (nft_set_elem_expired(&rbe->ext))
return false;
if (!nft_set_ext_exists(&rbe->ext, NFT_SET_EXT_FLAGS) ||
(*nft_set_ext_flags(&rbe->ext) & NFT_SET_ELEM_INTERVAL_END) ==
(flags & NFT_SET_ELEM_INTERVAL_END)) {
*elem = rbe;
return true;
}
if (nft_rbtree_interval_end(rbe))
interval = NULL;
parent = rcu_dereference_raw(parent->rb_left);
}
}
if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
nft_set_elem_active(&interval->ext, genmask) &&
!nft_set_elem_expired(&interval->ext) &&
((!nft_rbtree_interval_end(interval) &&
!(flags & NFT_SET_ELEM_INTERVAL_END)) ||
(nft_rbtree_interval_end(interval) &&
(flags & NFT_SET_ELEM_INTERVAL_END)))) {
*elem = interval;
return true;
}
return false;
}
static struct nft_elem_priv *
nft_rbtree_get(const struct net *net, const struct nft_set *set,
const struct nft_set_elem *elem, unsigned int flags)
{
struct nft_rbtree *priv = nft_set_priv(set);
unsigned int seq = read_seqcount_begin(&priv->count);
struct nft_rbtree_elem *rbe = ERR_PTR(-ENOENT);
const u32 *key = (const u32 *)&elem->key.val;
u8 genmask = nft_genmask_cur(net);
bool ret;
ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
if (ret || !read_seqcount_retry(&priv->count, seq))
return &rbe->priv;
read_lock_bh(&priv->lock);
seq = read_seqcount_begin(&priv->count);
ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
read_unlock_bh(&priv->lock);
if (!ret)
return ERR_PTR(-ENOENT);
return &rbe->priv;
}
static void nft_rbtree_gc_elem_remove(struct net *net, struct nft_set *set,
struct nft_rbtree *priv,
struct nft_rbtree_elem *rbe)
{
lockdep_assert_held_write(&priv->lock);
nft_setelem_data_deactivate(net, set, &rbe->priv);
rb_erase(&rbe->node, &priv->root);
}
static const struct nft_rbtree_elem *
nft_rbtree_gc_elem(const struct nft_set *__set, struct nft_rbtree *priv,
struct nft_rbtree_elem *rbe)
{
struct nft_set *set = (struct nft_set *)__set;
struct rb_node *prev = rb_prev(&rbe->node);
struct net *net = read_pnet(&set->net);
struct nft_rbtree_elem *rbe_prev;
struct nft_trans_gc *gc;
gc = nft_trans_gc_alloc(set, 0, GFP_ATOMIC);
if (!gc)
return ERR_PTR(-ENOMEM);
/* search for end interval coming before this element.
* end intervals don't carry a timeout extension, they
* are coupled with the interval start element.
*/
while (prev) {
rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
if (nft_rbtree_interval_end(rbe_prev) &&
nft_set_elem_active(&rbe_prev->ext, NFT_GENMASK_ANY))
break;
prev = rb_prev(prev);
}
rbe_prev = NULL;
if (prev) {
rbe_prev = rb_entry(prev, struct nft_rbtree_elem, node);
nft_rbtree_gc_elem_remove(net, set, priv, rbe_prev);
/* There is always room in this trans gc for this element,
* memory allocation never actually happens, hence, the warning
* splat in such case. No need to set NFT_SET_ELEM_DEAD_BIT,
* this is synchronous gc which never fails.
*/
gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
if (WARN_ON_ONCE(!gc))
return ERR_PTR(-ENOMEM);
nft_trans_gc_elem_add(gc, rbe_prev);
}
nft_rbtree_gc_elem_remove(net, set, priv, rbe);
gc = nft_trans_gc_queue_sync(gc, GFP_ATOMIC);
if (WARN_ON_ONCE(!gc))
return ERR_PTR(-ENOMEM);
nft_trans_gc_elem_add(gc, rbe);
nft_trans_gc_queue_sync_done(gc);
return rbe_prev;
}
static bool nft_rbtree_update_first(const struct nft_set *set,
struct nft_rbtree_elem *rbe,
struct rb_node *first)
{
struct nft_rbtree_elem *first_elem;
first_elem = rb_entry(first, struct nft_rbtree_elem, node);
/* this element is closest to where the new element is to be inserted:
* update the first element for the node list path.
*/
if (nft_rbtree_cmp(set, rbe, first_elem) < 0)
return true;
return false;
}
static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
struct nft_rbtree_elem *new,
struct nft_elem_priv **elem_priv)
{
struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL;
struct rb_node *node, *next, *parent, **p, *first = NULL;
struct nft_rbtree *priv = nft_set_priv(set);
u8 cur_genmask = nft_genmask_cur(net);
u8 genmask = nft_genmask_next(net);
u64 tstamp = nft_net_tstamp(net);
int d;
/* Descend the tree to search for an existing element greater than the
* key value to insert that is greater than the new element. This is the
* first element to walk the ordered elements to find possible overlap.
*/
parent = NULL;
p = &priv->root.rb_node;
while (*p != NULL) {
parent = *p;
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
d = nft_rbtree_cmp(set, rbe, new);
if (d < 0) {
p = &parent->rb_left;
} else if (d > 0) {
if (!first ||
nft_rbtree_update_first(set, rbe, first))
first = &rbe->node;
p = &parent->rb_right;
} else {
if (nft_rbtree_interval_end(rbe))
p = &parent->rb_left;
else
p = &parent->rb_right;
}
}
if (!first)
first = rb_first(&priv->root);
/* Detect overlap by going through the list of valid tree nodes.
* Values stored in the tree are in reversed order, starting from
* highest to lowest value.
*/
for (node = first; node != NULL; node = next) {
next = rb_next(node);
rbe = rb_entry(node, struct nft_rbtree_elem, node);
if (!nft_set_elem_active(&rbe->ext, genmask))
continue;
/* perform garbage collection to avoid bogus overlap reports
* but skip new elements in this transaction.
*/
if (__nft_set_elem_expired(&rbe->ext, tstamp) &&
nft_set_elem_active(&rbe->ext, cur_genmask)) {
const struct nft_rbtree_elem *removed_end;
removed_end = nft_rbtree_gc_elem(set, priv, rbe);
if (IS_ERR(removed_end))
return PTR_ERR(removed_end);
if (removed_end == rbe_le || removed_end == rbe_ge)
return -EAGAIN;
continue;
}
d = nft_rbtree_cmp(set, rbe, new);
if (d == 0) {
/* Matching end element: no need to look for an
* overlapping greater or equal element.
*/
if (nft_rbtree_interval_end(rbe)) {
rbe_le = rbe;
break;
}
/* first element that is greater or equal to key value. */
if (!rbe_ge) {
rbe_ge = rbe;
continue;
}
/* this is a closer more or equal element, update it. */
if (nft_rbtree_cmp(set, rbe_ge, new) != 0) {
rbe_ge = rbe;
continue;
}
/* element is equal to key value, make sure flags are
* the same, an existing more or equal start element
* must not be replaced by more or equal end element.
*/
if ((nft_rbtree_interval_start(new) &&
nft_rbtree_interval_start(rbe_ge)) ||
(nft_rbtree_interval_end(new) &&
nft_rbtree_interval_end(rbe_ge))) {
rbe_ge = rbe;
continue;
}
} else if (d > 0) {
/* annotate element greater than the new element. */
rbe_ge = rbe;
continue;
} else if (d < 0) {
/* annotate element less than the new element. */
rbe_le = rbe;
break;
}
}
/* - new start element matching existing start element: full overlap
* reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given.
*/
if (rbe_ge && !nft_rbtree_cmp(set, new, rbe_ge) &&
nft_rbtree_interval_start(rbe_ge) == nft_rbtree_interval_start(new)) {
*elem_priv = &rbe_ge->priv;
return -EEXIST;
}
/* - new end element matching existing end element: full overlap
* reported as -EEXIST, cleared by caller if NLM_F_EXCL is not given.
*/
if (rbe_le && !nft_rbtree_cmp(set, new, rbe_le) &&
nft_rbtree_interval_end(rbe_le) == nft_rbtree_interval_end(new)) {
*elem_priv = &rbe_le->priv;
return -EEXIST;
}
/* - new start element with existing closest, less or equal key value
* being a start element: partial overlap, reported as -ENOTEMPTY.
* Anonymous sets allow for two consecutive start element since they
* are constant, skip them to avoid bogus overlap reports.
*/
if (!nft_set_is_anonymous(set) && rbe_le &&
nft_rbtree_interval_start(rbe_le) && nft_rbtree_interval_start(new))
return -ENOTEMPTY;
/* - new end element with existing closest, less or equal key value
* being a end element: partial overlap, reported as -ENOTEMPTY.
*/
if (rbe_le &&
nft_rbtree_interval_end(rbe_le) && nft_rbtree_interval_end(new))
return -ENOTEMPTY;
/* - new end element with existing closest, greater or equal key value
* being an end element: partial overlap, reported as -ENOTEMPTY
*/
if (rbe_ge &&
nft_rbtree_interval_end(rbe_ge) && nft_rbtree_interval_end(new))
return -ENOTEMPTY;
/* Accepted element: pick insertion point depending on key value */
parent = NULL;
p = &priv->root.rb_node;
while (*p != NULL) {
parent = *p;
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
d = nft_rbtree_cmp(set, rbe, new);
if (d < 0)
p = &parent->rb_left;
else if (d > 0)
p = &parent->rb_right;
else if (nft_rbtree_interval_end(rbe))
p = &parent->rb_left;
else
p = &parent->rb_right;
}
rb_link_node_rcu(&new->node, parent, p);
rb_insert_color(&new->node, &priv->root);
return 0;
}
static int nft_rbtree_insert(const struct net *net, const struct nft_set *set,
const struct nft_set_elem *elem,
struct nft_elem_priv **elem_priv)
{
struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem->priv);
struct nft_rbtree *priv = nft_set_priv(set);
int err;
do {
if (fatal_signal_pending(current))
return -EINTR;
cond_resched();
write_lock_bh(&priv->lock);
write_seqcount_begin(&priv->count);
err = __nft_rbtree_insert(net, set, rbe, elem_priv);
write_seqcount_end(&priv->count);
write_unlock_bh(&priv->lock);
} while (err == -EAGAIN);
return err;
}
static void nft_rbtree_erase(struct nft_rbtree *priv, struct nft_rbtree_elem *rbe)
{
write_lock_bh(&priv->lock);
write_seqcount_begin(&priv->count);
rb_erase(&rbe->node, &priv->root);
write_seqcount_end(&priv->count);
write_unlock_bh(&priv->lock);
}
static void nft_rbtree_remove(const struct net *net,
const struct nft_set *set,
struct nft_elem_priv *elem_priv)
{
struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem_priv);
struct nft_rbtree *priv = nft_set_priv(set);
nft_rbtree_erase(priv, rbe);
}
static void nft_rbtree_activate(const struct net *net,
const struct nft_set *set,
struct nft_elem_priv *elem_priv)
{
struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem_priv);
nft_clear(net, &rbe->ext);
}
static void nft_rbtree_flush(const struct net *net,
const struct nft_set *set,
struct nft_elem_priv *elem_priv)
{
struct nft_rbtree_elem *rbe = nft_elem_priv_cast(elem_priv);
nft_set_elem_change_active(net, set, &rbe->ext);
}
static struct nft_elem_priv *
nft_rbtree_deactivate(const struct net *net, const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_rbtree_elem *rbe, *this = nft_elem_priv_cast(elem->priv);
const struct nft_rbtree *priv = nft_set_priv(set);
const struct rb_node *parent = priv->root.rb_node;
u8 genmask = nft_genmask_next(net);
u64 tstamp = nft_net_tstamp(net);
int d;
while (parent != NULL) {
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
d = memcmp(nft_set_ext_key(&rbe->ext), &elem->key.val,
set->klen);
if (d < 0)
parent = parent->rb_left;
else if (d > 0)
parent = parent->rb_right;
else {
if (nft_rbtree_interval_end(rbe) &&
nft_rbtree_interval_start(this)) {
parent = parent->rb_left;
continue;
} else if (nft_rbtree_interval_start(rbe) &&
nft_rbtree_interval_end(this)) {
parent = parent->rb_right;
continue;
} else if (__nft_set_elem_expired(&rbe->ext, tstamp)) {
break;
} else if (!nft_set_elem_active(&rbe->ext, genmask)) {
parent = parent->rb_left;
continue;
}
nft_rbtree_flush(net, set, &rbe->priv);
return &rbe->priv;
}
}
return NULL;
}
static void nft_rbtree_walk(const struct nft_ctx *ctx,
struct nft_set *set,
struct nft_set_iter *iter)
{
struct nft_rbtree *priv = nft_set_priv(set);
struct nft_rbtree_elem *rbe;
struct rb_node *node;
read_lock_bh(&priv->lock);
for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
rbe = rb_entry(node, struct nft_rbtree_elem, node);
if (iter->count < iter->skip)
goto cont;
iter->err = iter->fn(ctx, set, iter, &rbe->priv);
if (iter->err < 0) {
read_unlock_bh(&priv->lock);
return;
}
cont:
iter->count++;
}
read_unlock_bh(&priv->lock);
}
static void nft_rbtree_gc_remove(struct net *net, struct nft_set *set,
struct nft_rbtree *priv,
struct nft_rbtree_elem *rbe)
{
nft_setelem_data_deactivate(net, set, &rbe->priv);
nft_rbtree_erase(priv, rbe);
}
static void nft_rbtree_gc(struct nft_set *set)
{
struct nft_rbtree *priv = nft_set_priv(set);
struct nft_rbtree_elem *rbe, *rbe_end = NULL;
struct net *net = read_pnet(&set->net);
u64 tstamp = nft_net_tstamp(net);
struct rb_node *node, *next;
struct nft_trans_gc *gc;
set = nft_set_container_of(priv);
net = read_pnet(&set->net);
gc = nft_trans_gc_alloc(set, 0, GFP_KERNEL);
if (!gc)
return;
for (node = rb_first(&priv->root); node ; node = next) {
next = rb_next(node);
rbe = rb_entry(node, struct nft_rbtree_elem, node);
/* elements are reversed in the rbtree for historical reasons,
* from highest to lowest value, that is why end element is
* always visited before the start element.
*/
if (nft_rbtree_interval_end(rbe)) {
rbe_end = rbe;
continue;
}
if (!__nft_set_elem_expired(&rbe->ext, tstamp))
continue;
gc = nft_trans_gc_queue_sync(gc, GFP_KERNEL);
if (!gc)
goto try_later;
/* end element needs to be removed first, it has
* no timeout extension.
*/
if (rbe_end) {
nft_rbtree_gc_remove(net, set, priv, rbe_end);
nft_trans_gc_elem_add(gc, rbe_end);
rbe_end = NULL;
}
gc = nft_trans_gc_queue_sync(gc, GFP_KERNEL);
if (!gc)
goto try_later;
nft_rbtree_gc_remove(net, set, priv, rbe);
nft_trans_gc_elem_add(gc, rbe);
}
try_later:
if (gc) {
gc = nft_trans_gc_catchall_sync(gc);
nft_trans_gc_queue_sync_done(gc);
priv->last_gc = jiffies;
}
}
static u64 nft_rbtree_privsize(const struct nlattr * const nla[],
const struct nft_set_desc *desc)
{
return sizeof(struct nft_rbtree);
}
static int nft_rbtree_init(const struct nft_set *set,
const struct nft_set_desc *desc,
const struct nlattr * const nla[])
{
struct nft_rbtree *priv = nft_set_priv(set);
BUILD_BUG_ON(offsetof(struct nft_rbtree_elem, priv) != 0);
rwlock_init(&priv->lock);
seqcount_rwlock_init(&priv->count, &priv->lock);
priv->root = RB_ROOT;
return 0;
}
static void nft_rbtree_destroy(const struct nft_ctx *ctx,
const struct nft_set *set)
{
struct nft_rbtree *priv = nft_set_priv(set);
struct nft_rbtree_elem *rbe;
struct rb_node *node;
while ((node = priv->root.rb_node) != NULL) {
rb_erase(node, &priv->root);
rbe = rb_entry(node, struct nft_rbtree_elem, node);
nf_tables_set_elem_destroy(ctx, set, &rbe->priv);
}
}
static bool nft_rbtree_estimate(const struct nft_set_desc *desc, u32 features,
struct nft_set_estimate *est)
{
if (desc->field_count > 1)
return false;
if (desc->size)
est->size = sizeof(struct nft_rbtree) +
desc->size * sizeof(struct nft_rbtree_elem);
else
est->size = ~0;
est->lookup = NFT_SET_CLASS_O_LOG_N;
est->space = NFT_SET_CLASS_O_N;
return true;
}
static void nft_rbtree_commit(struct nft_set *set)
{
struct nft_rbtree *priv = nft_set_priv(set);
if (time_after_eq(jiffies, priv->last_gc + nft_set_gc_interval(set)))
nft_rbtree_gc(set);
}
static void nft_rbtree_gc_init(const struct nft_set *set)
{
struct nft_rbtree *priv = nft_set_priv(set);
priv->last_gc = jiffies;
}
const struct nft_set_type nft_set_rbtree_type = {
.features = NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT,
.ops = {
.privsize = nft_rbtree_privsize,
.elemsize = offsetof(struct nft_rbtree_elem, ext),
.estimate = nft_rbtree_estimate,
.init = nft_rbtree_init,
.destroy = nft_rbtree_destroy,
.insert = nft_rbtree_insert,
.remove = nft_rbtree_remove,
.deactivate = nft_rbtree_deactivate,
.flush = nft_rbtree_flush,
.activate = nft_rbtree_activate,
.commit = nft_rbtree_commit,
.gc_init = nft_rbtree_gc_init,
.lookup = nft_rbtree_lookup,
.walk = nft_rbtree_walk,
.get = nft_rbtree_get,
},
};
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