// SPDX-License-Identifier: GPL-2.0-only
|
/*
|
* count the number of connections matching an arbitrary key.
|
*
|
* (C) 2017 Red Hat GmbH
|
* Author: Florian Westphal <fw@strlen.de>
|
*
|
* split from xt_connlimit.c:
|
* (c) 2000 Gerd Knorr <kraxel@bytesex.org>
|
* Nov 2002: Martin Bene <martin.bene@icomedias.com>:
|
* only ignore TIME_WAIT or gone connections
|
* (C) CC Computer Consultants GmbH, 2007
|
*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/in.h>
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#include <linux/in6.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/jhash.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
|
#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/skbuff.h>
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#include <linux/spinlock.h>
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#include <linux/netfilter/nf_conntrack_tcp.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_count.h>
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#include <net/netfilter/nf_conntrack_core.h>
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#include <net/netfilter/nf_conntrack_tuple.h>
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#include <net/netfilter/nf_conntrack_zones.h>
|
|
#define CONNCOUNT_SLOTS 256U
|
|
#define CONNCOUNT_GC_MAX_NODES 8
|
#define MAX_KEYLEN 5
|
|
/* we will save the tuples of all connections we care about */
|
struct nf_conncount_tuple {
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struct list_head node;
|
struct nf_conntrack_tuple tuple;
|
struct nf_conntrack_zone zone;
|
int cpu;
|
u32 jiffies32;
|
};
|
|
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_SLOTS] __cacheline_aligned_in_smp;
|
|
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;
|
static struct kmem_cache *conncount_rb_cachep __read_mostly;
|
static struct kmem_cache *conncount_conn_cachep __read_mostly;
|
|
static inline bool already_closed(const struct nf_conn *conn)
|
{
|
if (nf_ct_protonum(conn) == IPPROTO_TCP)
|
return conn->proto.tcp.state == TCP_CONNTRACK_TIME_WAIT ||
|
conn->proto.tcp.state == TCP_CONNTRACK_CLOSE;
|
else
|
return false;
|
}
|
|
static int key_diff(const u32 *a, const u32 *b, unsigned int klen)
|
{
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return memcmp(a, b, klen * sizeof(u32));
|
}
|
|
static void conn_free(struct nf_conncount_list *list,
|
struct nf_conncount_tuple *conn)
|
{
|
lockdep_assert_held(&list->list_lock);
|
|
list->count--;
|
list_del(&conn->node);
|
|
kmem_cache_free(conncount_conn_cachep, conn);
|
}
|
|
static const struct nf_conntrack_tuple_hash *
|
find_or_evict(struct net *net, struct nf_conncount_list *list,
|
struct nf_conncount_tuple *conn)
|
{
|
const struct nf_conntrack_tuple_hash *found;
|
unsigned long a, b;
|
int cpu = raw_smp_processor_id();
|
u32 age;
|
|
found = nf_conntrack_find_get(net, &conn->zone, &conn->tuple);
|
if (found)
|
return found;
|
b = conn->jiffies32;
|
a = (u32)jiffies;
|
|
/* conn might have been added just before by another cpu and
|
* might still be unconfirmed. In this case, nf_conntrack_find()
|
* returns no result. Thus only evict if this cpu added the
|
* stale entry or if the entry is older than two jiffies.
|
*/
|
age = a - b;
|
if (conn->cpu == cpu || age >= 2) {
|
conn_free(list, conn);
|
return ERR_PTR(-ENOENT);
|
}
|
|
return ERR_PTR(-EAGAIN);
|
}
|
|
static int __nf_conncount_add(struct net *net,
|
struct nf_conncount_list *list,
|
const struct nf_conntrack_tuple *tuple,
|
const struct nf_conntrack_zone *zone)
|
{
|
const struct nf_conntrack_tuple_hash *found;
|
struct nf_conncount_tuple *conn, *conn_n;
|
struct nf_conn *found_ct;
|
unsigned int collect = 0;
|
|
/* check the saved connections */
|
list_for_each_entry_safe(conn, conn_n, &list->head, node) {
|
if (collect > CONNCOUNT_GC_MAX_NODES)
|
break;
|
|
found = find_or_evict(net, list, conn);
|
if (IS_ERR(found)) {
|
/* Not found, but might be about to be confirmed */
|
if (PTR_ERR(found) == -EAGAIN) {
|
if (nf_ct_tuple_equal(&conn->tuple, tuple) &&
|
nf_ct_zone_id(&conn->zone, conn->zone.dir) ==
|
nf_ct_zone_id(zone, zone->dir))
|
return 0; /* already exists */
|
} else {
|
collect++;
|
}
|
continue;
|
}
|
|
found_ct = nf_ct_tuplehash_to_ctrack(found);
|
|
if (nf_ct_tuple_equal(&conn->tuple, tuple) &&
|
nf_ct_zone_equal(found_ct, zone, zone->dir)) {
|
/*
|
* We should not see tuples twice unless someone hooks
|
* this into a table without "-p tcp --syn".
|
*
|
* Attempt to avoid a re-add in this case.
|
*/
|
nf_ct_put(found_ct);
|
return 0;
|
} else if (already_closed(found_ct)) {
|
/*
|
* we do not care about connections which are
|
* closed already -> ditch it
|
*/
|
nf_ct_put(found_ct);
|
conn_free(list, conn);
|
collect++;
|
continue;
|
}
|
|
nf_ct_put(found_ct);
|
}
|
|
if (WARN_ON_ONCE(list->count > INT_MAX))
|
return -EOVERFLOW;
|
|
conn = kmem_cache_alloc(conncount_conn_cachep, GFP_ATOMIC);
|
if (conn == NULL)
|
return -ENOMEM;
|
|
conn->tuple = *tuple;
|
conn->zone = *zone;
|
conn->cpu = raw_smp_processor_id();
|
conn->jiffies32 = (u32)jiffies;
|
list_add_tail(&conn->node, &list->head);
|
list->count++;
|
return 0;
|
}
|
|
int nf_conncount_add(struct net *net,
|
struct nf_conncount_list *list,
|
const struct nf_conntrack_tuple *tuple,
|
const struct nf_conntrack_zone *zone)
|
{
|
int ret;
|
|
/* check the saved connections */
|
spin_lock_bh(&list->list_lock);
|
ret = __nf_conncount_add(net, list, tuple, zone);
|
spin_unlock_bh(&list->list_lock);
|
|
return ret;
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}
|
EXPORT_SYMBOL_GPL(nf_conncount_add);
|
|
void nf_conncount_list_init(struct nf_conncount_list *list)
|
{
|
spin_lock_init(&list->list_lock);
|
INIT_LIST_HEAD(&list->head);
|
list->count = 0;
|
}
|
EXPORT_SYMBOL_GPL(nf_conncount_list_init);
|
|
/* Return true if the list is empty. Must be called with BH disabled. */
|
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 ret = false;
|
|
/* don't bother if other cpu is already doing GC */
|
if (!spin_trylock(&list->list_lock))
|
return false;
|
|
list_for_each_entry_safe(conn, conn_n, &list->head, node) {
|
found = find_or_evict(net, list, conn);
|
if (IS_ERR(found)) {
|
if (PTR_ERR(found) == -ENOENT)
|
collected++;
|
continue;
|
}
|
|
found_ct = nf_ct_tuplehash_to_ctrack(found);
|
if (already_closed(found_ct)) {
|
/*
|
* we do not care about connections which are
|
* closed already -> ditch it
|
*/
|
nf_ct_put(found_ct);
|
conn_free(list, conn);
|
collected++;
|
continue;
|
}
|
|
nf_ct_put(found_ct);
|
if (collected > CONNCOUNT_GC_MAX_NODES)
|
break;
|
}
|
|
if (!list->count)
|
ret = true;
|
spin_unlock(&list->list_lock);
|
|
return ret;
|
}
|
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);
|
}
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|
/* caller must hold tree nf_conncount_locks[] lock */
|
static void tree_nodes_free(struct rb_root *root,
|
struct nf_conncount_rb *gc_nodes[],
|
unsigned int gc_count)
|
{
|
struct nf_conncount_rb *rbconn;
|
|
while (gc_count) {
|
rbconn = gc_nodes[--gc_count];
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spin_lock(&rbconn->list.list_lock);
|
if (!rbconn->list.count) {
|
rb_erase(&rbconn->node, root);
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call_rcu(&rbconn->rcu_head, __tree_nodes_free);
|
}
|
spin_unlock(&rbconn->list.list_lock);
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}
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}
|
|
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 net *net,
|
struct nf_conncount_data *data,
|
struct rb_root *root,
|
unsigned int hash,
|
const u32 *key,
|
const struct nf_conntrack_tuple *tuple,
|
const struct nf_conntrack_zone *zone)
|
{
|
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, gc_count = 0;
|
u8 keylen = data->keylen;
|
bool do_gc = true;
|
|
spin_lock_bh(&nf_conncount_locks[hash]);
|
restart:
|
parent = NULL;
|
rbnode = &(root->rb_node);
|
while (*rbnode) {
|
int diff;
|
rbconn = rb_entry(*rbnode, struct nf_conncount_rb, node);
|
|
parent = *rbnode;
|
diff = key_diff(key, rbconn->key, keylen);
|
if (diff < 0) {
|
rbnode = &((*rbnode)->rb_left);
|
} else if (diff > 0) {
|
rbnode = &((*rbnode)->rb_right);
|
} else {
|
int ret;
|
|
ret = nf_conncount_add(net, &rbconn->list, tuple, zone);
|
if (ret)
|
count = 0; /* hotdrop */
|
else
|
count = rbconn->list.count;
|
tree_nodes_free(root, gc_nodes, gc_count);
|
goto out_unlock;
|
}
|
|
if (gc_count >= ARRAY_SIZE(gc_nodes))
|
continue;
|
|
if (do_gc && nf_conncount_gc_list(net, &rbconn->list))
|
gc_nodes[gc_count++] = rbconn;
|
}
|
|
if (gc_count) {
|
tree_nodes_free(root, gc_nodes, gc_count);
|
schedule_gc_worker(data, hash);
|
gc_count = 0;
|
do_gc = false;
|
goto restart;
|
}
|
|
/* expected case: match, insert new node */
|
rbconn = kmem_cache_alloc(conncount_rb_cachep, GFP_ATOMIC);
|
if (rbconn == NULL)
|
goto out_unlock;
|
|
conn = kmem_cache_alloc(conncount_conn_cachep, GFP_ATOMIC);
|
if (conn == NULL) {
|
kmem_cache_free(conncount_rb_cachep, rbconn);
|
goto out_unlock;
|
}
|
|
conn->tuple = *tuple;
|
conn->zone = *zone;
|
memcpy(rbconn->key, key, sizeof(u32) * keylen);
|
|
nf_conncount_list_init(&rbconn->list);
|
list_add(&conn->node, &rbconn->list.head);
|
count = 1;
|
rbconn->list.count = count;
|
|
rb_link_node_rcu(&rbconn->node, parent, rbnode);
|
rb_insert_color(&rbconn->node, root);
|
out_unlock:
|
spin_unlock_bh(&nf_conncount_locks[hash]);
|
return count;
|
}
|
|
static unsigned int
|
count_tree(struct net *net,
|
struct nf_conncount_data *data,
|
const u32 *key,
|
const struct nf_conntrack_tuple *tuple,
|
const struct nf_conntrack_zone *zone)
|
{
|
struct rb_root *root;
|
struct rb_node *parent;
|
struct nf_conncount_rb *rbconn;
|
unsigned int hash;
|
u8 keylen = data->keylen;
|
|
hash = jhash2(key, data->keylen, conncount_rnd) % CONNCOUNT_SLOTS;
|
root = &data->root[hash];
|
|
parent = rcu_dereference_raw(root->rb_node);
|
while (parent) {
|
int diff;
|
|
rbconn = rb_entry(parent, struct nf_conncount_rb, node);
|
|
diff = key_diff(key, rbconn->key, keylen);
|
if (diff < 0) {
|
parent = rcu_dereference_raw(parent->rb_left);
|
} else if (diff > 0) {
|
parent = rcu_dereference_raw(parent->rb_right);
|
} else {
|
int ret;
|
|
if (!tuple) {
|
nf_conncount_gc_list(net, &rbconn->list);
|
return rbconn->list.count;
|
}
|
|
spin_lock_bh(&rbconn->list.list_lock);
|
/* Node might be about to be free'd.
|
* We need to defer to insert_tree() in this case.
|
*/
|
if (rbconn->list.count == 0) {
|
spin_unlock_bh(&rbconn->list.list_lock);
|
break;
|
}
|
|
/* same source network -> be counted! */
|
ret = __nf_conncount_add(net, &rbconn->list, tuple, zone);
|
spin_unlock_bh(&rbconn->list.list_lock);
|
if (ret)
|
return 0; /* hotdrop */
|
else
|
return rbconn->list.count;
|
}
|
}
|
|
if (!tuple)
|
return 0;
|
|
return insert_tree(net, data, root, hash, key, tuple, zone);
|
}
|
|
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_SLOTS;
|
root = &data->root[tree];
|
|
local_bh_disable();
|
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_count++;
|
}
|
rcu_read_unlock();
|
local_bh_enable();
|
|
cond_resched();
|
|
spin_lock_bh(&nf_conncount_locks[tree]);
|
if (gc_count < ARRAY_SIZE(gc_nodes))
|
goto next; /* do not bother */
|
|
gc_count = 0;
|
node = rb_first(root);
|
while (node != NULL) {
|
rbconn = rb_entry(node, struct nf_conncount_rb, node);
|
node = rb_next(node);
|
|
if (rbconn->list.count > 0)
|
continue;
|
|
gc_nodes[gc_count++] = rbconn;
|
if (gc_count >= ARRAY_SIZE(gc_nodes)) {
|
tree_nodes_free(root, gc_nodes, gc_count);
|
gc_count = 0;
|
}
|
}
|
|
tree_nodes_free(root, gc_nodes, gc_count);
|
next:
|
clear_bit(tree, data->pending_trees);
|
|
next_tree = (tree + 1) % CONNCOUNT_SLOTS;
|
next_tree = find_next_bit(data->pending_trees, CONNCOUNT_SLOTS, next_tree);
|
|
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,
|
const u32 *key,
|
const struct nf_conntrack_tuple *tuple,
|
const struct nf_conntrack_zone *zone)
|
{
|
return count_tree(net, data, key, tuple, zone);
|
}
|
EXPORT_SYMBOL_GPL(nf_conncount_count);
|
|
struct nf_conncount_data *nf_conncount_init(struct net *net, unsigned int family,
|
unsigned int keylen)
|
{
|
struct nf_conncount_data *data;
|
int ret, i;
|
|
if (keylen % sizeof(u32) ||
|
keylen / sizeof(u32) > MAX_KEYLEN ||
|
keylen == 0)
|
return ERR_PTR(-EINVAL);
|
|
net_get_random_once(&conncount_rnd, sizeof(conncount_rnd));
|
|
data = kmalloc(sizeof(*data), GFP_KERNEL);
|
if (!data)
|
return ERR_PTR(-ENOMEM);
|
|
ret = nf_ct_netns_get(net, family);
|
if (ret < 0) {
|
kfree(data);
|
return ERR_PTR(ret);
|
}
|
|
for (i = 0; i < ARRAY_SIZE(data->root); ++i)
|
data->root[i] = RB_ROOT;
|
|
data->keylen = keylen / sizeof(u32);
|
data->net = net;
|
INIT_WORK(&data->gc_work, tree_gc_worker);
|
|
return data;
|
}
|
EXPORT_SYMBOL_GPL(nf_conncount_init);
|
|
void nf_conncount_cache_free(struct nf_conncount_list *list)
|
{
|
struct nf_conncount_tuple *conn, *conn_n;
|
|
list_for_each_entry_safe(conn, conn_n, &list->head, node)
|
kmem_cache_free(conncount_conn_cachep, conn);
|
}
|
EXPORT_SYMBOL_GPL(nf_conncount_cache_free);
|
|
static void destroy_tree(struct rb_root *r)
|
{
|
struct nf_conncount_rb *rbconn;
|
struct rb_node *node;
|
|
while ((node = rb_first(r)) != NULL) {
|
rbconn = rb_entry(node, struct nf_conncount_rb, node);
|
|
rb_erase(node, r);
|
|
nf_conncount_cache_free(&rbconn->list);
|
|
kmem_cache_free(conncount_rb_cachep, rbconn);
|
}
|
}
|
|
void nf_conncount_destroy(struct net *net, unsigned int family,
|
struct nf_conncount_data *data)
|
{
|
unsigned int i;
|
|
cancel_work_sync(&data->gc_work);
|
nf_ct_netns_put(net, family);
|
|
for (i = 0; i < ARRAY_SIZE(data->root); ++i)
|
destroy_tree(&data->root[i]);
|
|
kfree(data);
|
}
|
EXPORT_SYMBOL_GPL(nf_conncount_destroy);
|
|
static int __init nf_conncount_modinit(void)
|
{
|
int i;
|
|
for (i = 0; i < CONNCOUNT_SLOTS; ++i)
|
spin_lock_init(&nf_conncount_locks[i]);
|
|
conncount_conn_cachep = kmem_cache_create("nf_conncount_tuple",
|
sizeof(struct nf_conncount_tuple),
|
0, 0, NULL);
|
if (!conncount_conn_cachep)
|
return -ENOMEM;
|
|
conncount_rb_cachep = kmem_cache_create("nf_conncount_rb",
|
sizeof(struct nf_conncount_rb),
|
0, 0, NULL);
|
if (!conncount_rb_cachep) {
|
kmem_cache_destroy(conncount_conn_cachep);
|
return -ENOMEM;
|
}
|
|
return 0;
|
}
|
|
static void __exit nf_conncount_modexit(void)
|
{
|
kmem_cache_destroy(conncount_conn_cachep);
|
kmem_cache_destroy(conncount_rb_cachep);
|
}
|
|
module_init(nf_conncount_modinit);
|
module_exit(nf_conncount_modexit);
|
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
|
MODULE_AUTHOR("Florian Westphal <fw@strlen.de>");
|
MODULE_DESCRIPTION("netfilter: count number of connections matching a key");
|
MODULE_LICENSE("GPL");
|
