blob: d600a566da324ae7198635d81757ce78f7205489 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* 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;
struct delayed_work gc_work;
};
struct nft_rbtree_elem {
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 bool nft_rbtree_equal(const struct nft_set *set, const void *this,
const struct nft_rbtree_elem *interval)
{
return memcmp(this, nft_set_ext_key(&interval->ext), set->klen) == 0;
}
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;
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 (interval &&
nft_rbtree_equal(set, this, 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_set_elem_expired(&rbe->ext))
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_set_elem_expired(&interval->ext) &&
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 void *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;
read_lock_bh(&priv->lock);
seq = read_seqcount_begin(&priv->count);
ret = __nft_rbtree_get(net, set, key, &rbe, seq, flags, genmask);
if (!ret)
rbe = ERR_PTR(-ENOENT);
read_unlock_bh(&priv->lock);
return rbe;
}
static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set,
struct nft_rbtree_elem *new,
struct nft_set_ext **ext)
{
bool overlap = false, dup_end_left = false, dup_end_right = false;
struct nft_rbtree *priv = nft_set_priv(set);
u8 genmask = nft_genmask_next(net);
struct nft_rbtree_elem *rbe;
struct rb_node *parent, **p;
int d;
/* Detect overlaps as we descend the tree. Set the flag in these cases:
*
* a1. _ _ __>| ?_ _ __| (insert end before existing end)
* a2. _ _ ___| ?_ _ _>| (insert end after existing end)
* a3. _ _ ___? >|_ _ __| (insert start before existing end)
*
* and clear it later on, as we eventually reach the points indicated by
* '?' above, in the cases described below. We'll always meet these
* later, locally, due to tree ordering, and overlaps for the intervals
* that are the closest together are always evaluated last.
*
* b1. _ _ __>| !_ _ __| (insert end before existing start)
* b2. _ _ ___| !_ _ _>| (insert end after existing start)
* b3. _ _ ___! >|_ _ __| (insert start after existing end, as a leaf)
* '--' no nodes falling in this range
* b4. >|_ _ ! (insert start before existing start)
*
* Case a3. resolves to b3.:
* - if the inserted start element is the leftmost, because the '0'
* element in the tree serves as end element
* - otherwise, if an existing end is found immediately to the left. If
* there are existing nodes in between, we need to further descend the
* tree before we can conclude the new start isn't causing an overlap
*
* or to b4., which, preceded by a3., means we already traversed one or
* more existing intervals entirely, from the right.
*
* For a new, rightmost pair of elements, we'll hit cases b3. and b2.,
* in that order.
*
* The flag is also cleared in two special cases:
*
* b5. |__ _ _!|<_ _ _ (insert start right before existing end)
* b6. |__ _ >|!__ _ _ (insert end right after existing start)
*
* which always happen as last step and imply that no further
* overlapping is possible.
*
* Another special case comes from the fact that start elements matching
* an already existing start element are allowed: insertion is not
* performed but we return -EEXIST in that case, and the error will be
* cleared by the caller if NLM_F_EXCL is not present in the request.
* This way, request for insertion of an exact overlap isn't reported as
* error to userspace if not desired.
*
* However, if the existing start matches a pre-existing start, but the
* end element doesn't match the corresponding pre-existing end element,
* we need to report a partial overlap. This is a local condition that
* can be noticed without need for a tracking flag, by checking for a
* local duplicated end for a corresponding start, from left and right,
* separately.
*/
parent = NULL;
p = &priv->root.rb_node;
while (*p != NULL) {
parent = *p;
rbe = rb_entry(parent, struct nft_rbtree_elem, node);
d = memcmp(nft_set_ext_key(&rbe->ext),
nft_set_ext_key(&new->ext),
set->klen);
if (d < 0) {
p = &parent->rb_left;
if (nft_rbtree_interval_start(new)) {
if (nft_rbtree_interval_end(rbe) &&
nft_set_elem_active(&rbe->ext, genmask) &&
!nft_set_elem_expired(&rbe->ext) && !*p)
overlap = false;
} else {
if (dup_end_left && !*p)
return -ENOTEMPTY;
overlap = nft_rbtree_interval_end(rbe) &&
nft_set_elem_active(&rbe->ext,
genmask) &&
!nft_set_elem_expired(&rbe->ext);
if (overlap) {
dup_end_right = true;
continue;
}
}
} else if (d > 0) {
p = &parent->rb_right;
if (nft_rbtree_interval_end(new)) {
if (dup_end_right && !*p)
return -ENOTEMPTY;
overlap = nft_rbtree_interval_end(rbe) &&
nft_set_elem_active(&rbe->ext,
genmask) &&
!nft_set_elem_expired(&rbe->ext);
if (overlap) {
dup_end_left = true;
continue;
}
} else if (nft_set_elem_active(&rbe->ext, genmask) &&
!nft_set_elem_expired(&rbe->ext)) {
overlap = nft_rbtree_interval_end(rbe);
}
} else {
if (nft_rbtree_interval_end(rbe) &&
nft_rbtree_interval_start(new)) {
p = &parent->rb_left;
if (nft_set_elem_active(&rbe->ext, genmask) &&
!nft_set_elem_expired(&rbe->ext))
overlap = false;
} else if (nft_rbtree_interval_start(rbe) &&
nft_rbtree_interval_end(new)) {
p = &parent->rb_right;
if (nft_set_elem_active(&rbe->ext, genmask) &&
!nft_set_elem_expired(&rbe->ext))
overlap = false;
} else if (nft_set_elem_active(&rbe->ext, genmask) &&
!nft_set_elem_expired(&rbe->ext)) {
*ext = &rbe->ext;
return -EEXIST;
} else {
p = &parent->rb_left;
}
}
dup_end_left = dup_end_right = false;
}
if (overlap)
return -ENOTEMPTY;
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_set_ext **ext)
{
struct nft_rbtree *priv = nft_set_priv(set);
struct nft_rbtree_elem *rbe = elem->priv;
int err;
write_lock_bh(&priv->lock);
write_seqcount_begin(&priv->count);
err = __nft_rbtree_insert(net, set, rbe, ext);
write_seqcount_end(&priv->count);
write_unlock_bh(&priv->lock);
return err;
}
static void nft_rbtree_remove(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_rbtree *priv = nft_set_priv(set);
struct nft_rbtree_elem *rbe = elem->priv;
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_activate(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem)
{
struct nft_rbtree_elem *rbe = elem->priv;
nft_set_elem_change_active(net, set, &rbe->ext);
nft_set_elem_clear_busy(&rbe->ext);
}
static bool nft_rbtree_flush(const struct net *net,
const struct nft_set *set, void *priv)
{
struct nft_rbtree_elem *rbe = priv;
if (!nft_set_elem_mark_busy(&rbe->ext) ||
!nft_is_active(net, &rbe->ext)) {
nft_set_elem_change_active(net, set, &rbe->ext);
return true;
}
return false;
}
static void *nft_rbtree_deactivate(const struct net *net,
const struct nft_set *set,
const struct nft_set_elem *elem)
{
const struct nft_rbtree *priv = nft_set_priv(set);
const struct rb_node *parent = priv->root.rb_node;
struct nft_rbtree_elem *rbe, *this = elem->priv;
u8 genmask = nft_genmask_next(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_active(&rbe->ext, genmask)) {
parent = parent->rb_left;
continue;
}
nft_rbtree_flush(net, set, rbe);
return rbe;
}
}
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 nft_set_elem elem;
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;
if (nft_set_elem_expired(&rbe->ext))
goto cont;
if (!nft_set_elem_active(&rbe->ext, iter->genmask))
goto cont;
elem.priv = rbe;
iter->err = iter->fn(ctx, set, iter, &elem);
if (iter->err < 0) {
read_unlock_bh(&priv->lock);
return;
}
cont:
iter->count++;
}
read_unlock_bh(&priv->lock);
}
static void nft_rbtree_gc(struct work_struct *work)
{
struct nft_rbtree_elem *rbe, *rbe_end = NULL, *rbe_prev = NULL;
struct nft_set_gc_batch *gcb = NULL;
struct nft_rbtree *priv;
struct rb_node *node;
struct nft_set *set;
priv = container_of(work, struct nft_rbtree, gc_work.work);
set = nft_set_container_of(priv);
write_lock_bh(&priv->lock);
write_seqcount_begin(&priv->count);
for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
rbe = rb_entry(node, struct nft_rbtree_elem, node);
if (nft_rbtree_interval_end(rbe)) {
rbe_end = rbe;
continue;
}
if (!nft_set_elem_expired(&rbe->ext))
continue;
if (nft_set_elem_mark_busy(&rbe->ext))
continue;
if (rbe_prev) {
rb_erase(&rbe_prev->node, &priv->root);
rbe_prev = NULL;
}
gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
if (!gcb)
break;
atomic_dec(&set->nelems);
nft_set_gc_batch_add(gcb, rbe);
rbe_prev = rbe;
if (rbe_end) {
atomic_dec(&set->nelems);
nft_set_gc_batch_add(gcb, rbe_end);
rb_erase(&rbe_end->node, &priv->root);
rbe_end = NULL;
}
node = rb_next(node);
if (!node)
break;
}
if (rbe_prev)
rb_erase(&rbe_prev->node, &priv->root);
write_seqcount_end(&priv->count);
write_unlock_bh(&priv->lock);
rbe = nft_set_catchall_gc(set);
if (rbe) {
gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
if (gcb)
nft_set_gc_batch_add(gcb, rbe);
}
nft_set_gc_batch_complete(gcb);
queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
nft_set_gc_interval(set));
}
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);
rwlock_init(&priv->lock);
seqcount_rwlock_init(&priv->count, &priv->lock);
priv->root = RB_ROOT;
INIT_DEFERRABLE_WORK(&priv->gc_work, nft_rbtree_gc);
if (set->flags & NFT_SET_TIMEOUT)
queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
nft_set_gc_interval(set));
return 0;
}
static void nft_rbtree_destroy(const struct nft_set *set)
{
struct nft_rbtree *priv = nft_set_priv(set);
struct nft_rbtree_elem *rbe;
struct rb_node *node;
cancel_delayed_work_sync(&priv->gc_work);
rcu_barrier();
while ((node = priv->root.rb_node) != NULL) {
rb_erase(node, &priv->root);
rbe = rb_entry(node, struct nft_rbtree_elem, node);
nft_set_elem_destroy(set, rbe, true);
}
}
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;
}
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,
.lookup = nft_rbtree_lookup,
.walk = nft_rbtree_walk,
.get = nft_rbtree_get,
},
};