@@ -5,9 +5,17 @@
struct nf_conncount_data;
+enum nf_conncount_list_add {
+ NF_CONNCOUNT_ADDED, /* list add was ok */
+ NF_CONNCOUNT_ERR, /* -ENOMEM, must drop skb */
+ NF_CONNCOUNT_SKIP, /* list is already reclaimed by gc */
+};
+
struct nf_conncount_list {
+ spinlock_t list_lock;
struct list_head head; /* connections with the same filtering key */
unsigned int count; /* length of list */
+ bool dead;
};
struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int family,
@@ -28,11 +36,12 @@ void nf_conncount_lookup(struct net *net, struct nf_conncount_list *list,
void nf_conncount_list_init(struct nf_conncount_list *list);
-bool nf_conncount_add(struct nf_conncount_list *list,
- const struct nf_conntrack_tuple *tuple,
- const struct nf_conntrack_zone *zone);
+enum nf_conncount_list_add
+nf_conncount_add(struct nf_conncount_list *list,
+ const struct nf_conntrack_tuple *tuple,
+ const struct nf_conntrack_zone *zone);
-void nf_conncount_gc_list(struct net *net,
+bool nf_conncount_gc_list(struct net *net,
struct nf_conncount_list *list);
void nf_conncount_cache_free(struct nf_conncount_list *list);
@@ -49,12 +49,14 @@ struct nf_conncount_tuple {
struct nf_conntrack_zone zone;
int cpu;
u32 jiffies32;
+ struct rcu_head rcu_head;
};
struct nf_conncount_rb {
struct rb_node node;
struct nf_conncount_list list;
u32 key[MAX_KEYLEN];
+ struct rcu_head rcu_head;
};
static spinlock_t nf_conncount_locks[CONNCOUNT_LOCK_SLOTS] __cacheline_aligned_in_smp;
@@ -62,6 +64,10 @@ static spinlock_t nf_conncount_locks[CONNCOUNT_LOCK_SLOTS] __cacheline_aligned_i
struct nf_conncount_data {
unsigned int keylen;
struct rb_root root[CONNCOUNT_SLOTS];
+ struct net *net;
+ struct work_struct gc_work;
+ unsigned long pending_trees[BITS_TO_LONGS(CONNCOUNT_SLOTS)];
+ unsigned int gc_tree;
};
static u_int32_t conncount_rnd __read_mostly;
@@ -82,42 +88,70 @@ static int key_diff(const u32 *a, const u32 *b, unsigned int klen)
return memcmp(a, b, klen * sizeof(u32));
}
-bool nf_conncount_add(struct nf_conncount_list *list,
- const struct nf_conntrack_tuple *tuple,
- const struct nf_conntrack_zone *zone)
+enum nf_conncount_list_add
+nf_conncount_add(struct nf_conncount_list *list,
+ const struct nf_conntrack_tuple *tuple,
+ const struct nf_conntrack_zone *zone)
{
struct nf_conncount_tuple *conn;
if (WARN_ON_ONCE(list->count > INT_MAX))
- return false;
+ return NF_CONNCOUNT_ERR;
conn = kmem_cache_alloc(conncount_conn_cachep, GFP_ATOMIC);
if (conn == NULL)
- return false;
+ return NF_CONNCOUNT_ERR;
+
conn->tuple = *tuple;
conn->zone = *zone;
conn->cpu = raw_smp_processor_id();
conn->jiffies32 = (u32)jiffies;
+ spin_lock(&list->list_lock);
+ if (list->dead == true) {
+ kmem_cache_free(conncount_conn_cachep, conn);
+ spin_unlock(&list->list_lock);
+ return NF_CONNCOUNT_SKIP;
+ }
list_add_tail(&conn->node, &list->head);
list->count++;
- return true;
+ spin_unlock(&list->list_lock);
+ return NF_CONNCOUNT_ADDED;
}
EXPORT_SYMBOL_GPL(nf_conncount_add);
-static void conn_free(struct nf_conncount_list *list,
+static void __conn_free(struct rcu_head *h)
+{
+ struct nf_conncount_tuple *conn;
+
+ conn = container_of(h, struct nf_conncount_tuple, rcu_head);
+ kmem_cache_free(conncount_conn_cachep, conn);
+}
+
+static bool conn_free(struct nf_conncount_list *list,
struct nf_conncount_tuple *conn)
{
- if (WARN_ON_ONCE(list->count == 0))
- return;
+ bool free_entry = false;
+
+ spin_lock(&list->list_lock);
+
+ if (list->count == 0) {
+ spin_unlock(&list->list_lock);
+ return free_entry;
+ }
list->count--;
- list_del(&conn->node);
- kmem_cache_free(conncount_conn_cachep, conn);
+ list_del_rcu(&conn->node);
+ if (list->count == 0)
+ free_entry = true;
+
+ spin_unlock(&list->list_lock);
+ call_rcu(&conn->rcu_head, __conn_free);
+ return free_entry;
}
static const struct nf_conntrack_tuple_hash *
find_or_evict(struct net *net, struct nf_conncount_list *list,
- struct nf_conncount_tuple *conn)
+ struct nf_conncount_tuple *conn, bool *free_entry)
{
const struct nf_conntrack_tuple_hash *found;
unsigned long a, b;
@@ -137,7 +171,7 @@ find_or_evict(struct net *net, struct nf_conncount_list *list,
*/
age = a - b;
if (conn->cpu == cpu || age >= 2) {
- conn_free(list, conn);
+ *free_entry = conn_free(list, conn);
return ERR_PTR(-ENOENT);
}
@@ -154,6 +188,7 @@ void nf_conncount_lookup(struct net *net,
struct nf_conncount_tuple *conn, *conn_n;
struct nf_conn *found_ct;
unsigned int collect = 0;
+ bool free_entry = false;
/* best effort only */
*addit = tuple ? true : false;
@@ -163,7 +198,7 @@ void nf_conncount_lookup(struct net *net,
if (collect > CONNCOUNT_GC_MAX_NODES)
break;
- found = find_or_evict(net, list, conn);
+ found = find_or_evict(net, list, conn, &free_entry);
if (IS_ERR(found)) {
/* Not found, but might be about to be confirmed */
if (PTR_ERR(found) == -EAGAIN) {
@@ -208,24 +243,31 @@ EXPORT_SYMBOL_GPL(nf_conncount_lookup);
void nf_conncount_list_init(struct nf_conncount_list *list)
{
+ spin_lock_init(&list->list_lock);
INIT_LIST_HEAD(&list->head);
list->count = 1;
+ list->dead = false;
}
EXPORT_SYMBOL_GPL(nf_conncount_list_init);
-void nf_conncount_gc_list(struct net *net,
+/* Return true if the list is empty */
+bool nf_conncount_gc_list(struct net *net,
struct nf_conncount_list *list)
{
const struct nf_conntrack_tuple_hash *found;
struct nf_conncount_tuple *conn, *conn_n;
struct nf_conn *found_ct;
unsigned int collected = 0;
+ bool free_entry = false;
list_for_each_entry_safe(conn, conn_n, &list->head, node) {
- found = find_or_evict(net, list, conn);
+ found = find_or_evict(net, list, conn, &free_entry);
if (IS_ERR(found)) {
- if (PTR_ERR(found) == -ENOENT)
+ if (PTR_ERR(found) == -ENOENT) {
+ if (free_entry)
+ return true;
collected++;
+ }
continue;
}
@@ -236,18 +278,28 @@ void nf_conncount_gc_list(struct net *net,
* closed already -> ditch it
*/
nf_ct_put(found_ct);
- conn_free(list, conn);
+ if (conn_free(list, conn))
+ return true;
collected++;
continue;
}
nf_ct_put(found_ct);
if (collected > CONNCOUNT_GC_MAX_NODES)
- return;
+ return false;
}
+ return false;
}
EXPORT_SYMBOL_GPL(nf_conncount_gc_list);
+static void __tree_nodes_free(struct rcu_head *h)
+{
+ struct nf_conncount_rb *rbconn;
+
+ rbconn = container_of(h, struct nf_conncount_rb, rcu_head);
+ kmem_cache_free(conncount_rb_cachep, rbconn);
+}
+
static void tree_nodes_free(struct rb_root *root,
struct nf_conncount_rb *gc_nodes[],
unsigned int gc_count)
@@ -256,23 +308,39 @@ static void tree_nodes_free(struct rb_root *root,
while (gc_count) {
rbconn = gc_nodes[--gc_count];
- rb_erase(&rbconn->node, root);
- kmem_cache_free(conncount_rb_cachep, rbconn);
+ spin_lock(&rbconn->list.list_lock);
+ if (rbconn->list.count == 0 && rbconn->list.dead == false) {
+ rbconn->list.dead = true;
+ rb_erase(&rbconn->node, root);
+ call_rcu(&rbconn->rcu_head, __tree_nodes_free);
+ }
+ spin_unlock(&rbconn->list.list_lock);
}
}
+static void schedule_gc_worker(struct nf_conncount_data *data, int tree)
+{
+ set_bit(tree, data->pending_trees);
+ schedule_work(&data->gc_work);
+}
+
static unsigned int
-insert_tree(struct rb_root *root,
+insert_tree(struct net *net,
+ struct nf_conncount_data *data,
+ struct rb_root *root,
unsigned int hash,
const u32 *key,
u8 keylen,
const struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_zone *zone)
{
+ enum nf_conncount_list_add ret;
+ struct nf_conncount_rb *gc_nodes[CONNCOUNT_GC_MAX_NODES];
struct rb_node **rbnode, *parent;
struct nf_conncount_rb *rbconn;
struct nf_conncount_tuple *conn;
- unsigned int count = 0;
+ unsigned int count = 0, gc_count = 0;
+ bool node_found = false;
spin_lock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
@@ -290,16 +358,44 @@ insert_tree(struct rb_root *root,
rbnode = &((*rbnode)->rb_right);
} else {
/* unlikely: other cpu added node already */
- if (!nf_conncount_add(&rbconn->list, tuple, zone)) {
+ node_found = true;
+ ret = nf_conncount_add(&rbconn->list, tuple, zone);
+ if (ret == NF_CONNCOUNT_ERR) {
count = 0; /* hotdrop */
- goto out_unlock;
+ } else if (ret == NF_CONNCOUNT_ADDED) {
+ count = rbconn->list.count;
+ } else {
+ /* NF_CONNCOUNT_SKIP, rbconn is already
+ * reclaimed by gc, insert a new tree node
+ */
+ node_found = false;
}
-
- count = rbconn->list.count;
- goto out_unlock;
+ break;
}
+
+ if (gc_count >= ARRAY_SIZE(gc_nodes))
+ continue;
+
+ if (nf_conncount_gc_list(net, &rbconn->list))
+ gc_nodes[gc_count++] = rbconn;
+ }
+
+ if (gc_count) {
+ tree_nodes_free(root, gc_nodes, gc_count);
+ /* tree_node_free before new allocation permits
+ * allocator to re-use newly free'd object.
+ *
+ * This is a rare event; in most cases we will find
+ * existing node to re-use. (or gc_count is 0).
+ */
+
+ if (gc_count >= ARRAY_SIZE(gc_nodes))
+ schedule_gc_worker(data, hash);
}
+ if (node_found)
+ goto out_unlock;
+
/* expected case: match, insert new node */
rbconn = kmem_cache_alloc(conncount_rb_cachep, GFP_ATOMIC);
if (rbconn == NULL)
@@ -333,87 +429,97 @@ count_tree(struct net *net,
const struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_zone *zone)
{
- struct nf_conncount_rb *gc_nodes[CONNCOUNT_GC_MAX_NODES];
+ enum nf_conncount_list_add ret;
struct rb_root *root;
- struct rb_node **rbnode, *parent;
+ struct rb_node *parent;
struct nf_conncount_rb *rbconn;
- unsigned int gc_count, hash;
- bool no_gc = false;
- unsigned int count = 0;
+ unsigned int hash;
u8 keylen = data->keylen;
hash = jhash2(key, data->keylen, conncount_rnd) % CONNCOUNT_SLOTS;
root = &data->root[hash];
- spin_lock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
- restart:
- gc_count = 0;
- parent = NULL;
- rbnode = &(root->rb_node);
- while (*rbnode) {
+ parent = rcu_dereference_raw(root->rb_node);
+ while (parent) {
int diff;
bool addit;
- rbconn = rb_entry(*rbnode, struct nf_conncount_rb, node);
+ rbconn = rb_entry(parent, struct nf_conncount_rb, node);
- parent = *rbnode;
diff = key_diff(key, rbconn->key, keylen);
if (diff < 0) {
- rbnode = &((*rbnode)->rb_left);
+ parent = rcu_dereference_raw(parent->rb_left);
} else if (diff > 0) {
- rbnode = &((*rbnode)->rb_right);
+ parent = rcu_dereference_raw(parent->rb_right);
} else {
/* same source network -> be counted! */
nf_conncount_lookup(net, &rbconn->list, tuple, zone,
&addit);
- count = rbconn->list.count;
- tree_nodes_free(root, gc_nodes, gc_count);
if (!addit)
- goto out_unlock;
+ return rbconn->list.count;
+
+ ret = nf_conncount_add(&rbconn->list, tuple, zone);
+ if (ret == NF_CONNCOUNT_ERR) {
+ return 0; /* hotdrop */
+ } else if (ret == NF_CONNCOUNT_ADDED) {
+ return rbconn->list.count;
+ } else {
+ /* NF_CONNCOUNT_SKIP, rbconn is already
+ * reclaimed by gc, insert a new tree node
+ */
+ break;
+ }
+ }
+ }
- if (!nf_conncount_add(&rbconn->list, tuple, zone))
- count = 0; /* hotdrop */
- goto out_unlock;
+ if (!tuple)
+ return 0;
- count++;
- goto out_unlock;
- }
+ return insert_tree(net, data, root, hash, key, keylen, tuple, zone);
+}
- if (no_gc || gc_count >= ARRAY_SIZE(gc_nodes))
- continue;
+static void tree_gc_worker(struct work_struct *work)
+{
+ struct nf_conncount_data *data = container_of(work, struct nf_conncount_data, gc_work);
+ struct nf_conncount_rb *gc_nodes[CONNCOUNT_GC_MAX_NODES], *rbconn;
+ struct rb_root *root;
+ struct rb_node *node;
+ unsigned int tree, next_tree, gc_count = 0;
+
+ tree = data->gc_tree % CONNCOUNT_LOCK_SLOTS;
+ root = &data->root[tree];
- nf_conncount_gc_list(net, &rbconn->list);
- if (list_empty(&rbconn->list.head))
+ rcu_read_lock();
+ for (node = rb_first(root); node != NULL; node = rb_next(node)) {
+ rbconn = rb_entry(node, struct nf_conncount_rb, node);
+ if (nf_conncount_gc_list(data->net, &rbconn->list))
gc_nodes[gc_count++] = rbconn;
}
+ rcu_read_unlock();
+
+ spin_lock_bh(&nf_conncount_locks[tree]);
if (gc_count) {
- no_gc = true;
tree_nodes_free(root, gc_nodes, gc_count);
- /* tree_node_free before new allocation permits
- * allocator to re-use newly free'd object.
- *
- * This is a rare event; in most cases we will find
- * existing node to re-use. (or gc_count is 0).
- */
- goto restart;
}
- count = 0;
- if (!tuple)
- goto out_unlock;
+ clear_bit(tree, data->pending_trees);
- spin_unlock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
- return insert_tree(root, hash, key, keylen, tuple, zone);
+ next_tree = (tree + 1) % CONNCOUNT_SLOTS;
+ next_tree = find_next_bit(data->pending_trees, next_tree, CONNCOUNT_SLOTS);
-out_unlock:
- spin_unlock_bh(&nf_conncount_locks[hash % CONNCOUNT_LOCK_SLOTS]);
- return count;
+ if (next_tree < CONNCOUNT_SLOTS) {
+ data->gc_tree = next_tree;
+ schedule_work(work);
+ }
+
+ spin_unlock_bh(&nf_conncount_locks[tree]);
}
/* Count and return number of conntrack entries in 'net' with particular 'key'.
* If 'tuple' is not null, insert it into the accounting data structure.
+ * Call with RCU read lock.
*/
unsigned int nf_conncount_count(struct net *net,
struct nf_conncount_data *data,
@@ -452,6 +558,8 @@ struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int family
data->root[i] = RB_ROOT;
data->keylen = keylen / sizeof(u32);
+ data->net = net;
+ INIT_WORK(&data->gc_work, tree_gc_worker);
return data;
}
@@ -487,6 +595,7 @@ void nf_conncount_destroy(struct net *net, unsigned int family,
{
unsigned int i;
+ cancel_work_sync(&data->gc_work);
nf_ct_netns_put(net, family);
for (i = 0; i < ARRAY_SIZE(data->root); ++i)
@@ -14,7 +14,6 @@
#include <net/netfilter/nf_conntrack_zones.h>
struct nft_connlimit {
- spinlock_t lock;
struct nf_conncount_list list;
u32 limit;
bool invert;
@@ -45,7 +44,6 @@ static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
return;
}
- spin_lock_bh(&priv->lock);
nf_conncount_lookup(nft_net(pkt), &priv->list, tuple_ptr, zone,
&addit);
count = priv->list.count;
@@ -53,14 +51,12 @@ static inline void nft_connlimit_do_eval(struct nft_connlimit *priv,
if (!addit)
goto out;
- if (!nf_conncount_add(&priv->list, tuple_ptr, zone)) {
+ if (nf_conncount_add(&priv->list, tuple_ptr, zone) == NF_CONNCOUNT_ERR) {
regs->verdict.code = NF_DROP;
- spin_unlock_bh(&priv->lock);
return;
}
count++;
out:
- spin_unlock_bh(&priv->lock);
if ((count > priv->limit) ^ priv->invert) {
regs->verdict.code = NFT_BREAK;
@@ -88,7 +84,6 @@ static int nft_connlimit_do_init(const struct nft_ctx *ctx,
invert = true;
}
- spin_lock_init(&priv->lock);
nf_conncount_list_init(&priv->list);
priv->limit = limit;
priv->invert = invert;
@@ -213,7 +208,6 @@ static int nft_connlimit_clone(struct nft_expr *dst, const struct nft_expr *src)
struct nft_connlimit *priv_dst = nft_expr_priv(dst);
struct nft_connlimit *priv_src = nft_expr_priv(src);
- spin_lock_init(&priv_dst->lock);
nf_conncount_list_init(&priv_dst->list);
priv_dst->limit = priv_src->limit;
priv_dst->invert = priv_src->invert;
@@ -232,15 +226,8 @@ static void nft_connlimit_destroy_clone(const struct nft_ctx *ctx,
static bool nft_connlimit_gc(struct net *net, const struct nft_expr *expr)
{
struct nft_connlimit *priv = nft_expr_priv(expr);
- bool ret;
- spin_lock_bh(&priv->lock);
- nf_conncount_gc_list(net, &priv->list);
-
- ret = list_empty(&priv->list.head);
- spin_unlock_bh(&priv->lock);
-
- return ret;
+ return nf_conncount_gc_list(net, &priv->list);
}
static struct nft_expr_type nft_connlimit_type;