#include <linux/jhash.h>
#include <linux/slab.h>
#include <linux/list.h>
+#include <linux/rbtree.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_tuple.h>
#include <net/netfilter/nf_conntrack_zones.h>
+#define CONNLIMIT_SLOTS 256U
+
+#ifdef CONFIG_LOCKDEP
+#define CONNLIMIT_LOCK_SLOTS 8U
+#else
+#define CONNLIMIT_LOCK_SLOTS 256U
+#endif
+
+#define CONNLIMIT_GC_MAX_NODES 8
+
/* we will save the tuples of all connections we care about */
struct xt_connlimit_conn {
struct hlist_node node;
union nf_inet_addr addr;
};
+struct xt_connlimit_rb {
+ struct rb_node node;
+ struct hlist_head hhead; /* connections/hosts in same subnet */
+ union nf_inet_addr addr; /* search key */
+};
+
+static spinlock_t xt_connlimit_locks[CONNLIMIT_LOCK_SLOTS] __cacheline_aligned_in_smp;
+
struct xt_connlimit_data {
- struct hlist_head iphash[256];
- spinlock_t lock;
+ struct rb_root climit_root4[CONNLIMIT_SLOTS];
+ struct rb_root climit_root6[CONNLIMIT_SLOTS];
};
static u_int32_t connlimit_rnd __read_mostly;
+static struct kmem_cache *connlimit_rb_cachep __read_mostly;
+static struct kmem_cache *connlimit_conn_cachep __read_mostly;
static inline unsigned int connlimit_iphash(__be32 addr)
{
- return jhash_1word((__force __u32)addr, connlimit_rnd) & 0xFF;
+ return jhash_1word((__force __u32)addr,
+ connlimit_rnd) % CONNLIMIT_SLOTS;
}
static inline unsigned int
for (i = 0; i < ARRAY_SIZE(addr->ip6); ++i)
res.ip6[i] = addr->ip6[i] & mask->ip6[i];
- return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6), connlimit_rnd) & 0xFF;
+ return jhash2((u32 *)res.ip6, ARRAY_SIZE(res.ip6),
+ connlimit_rnd) % CONNLIMIT_SLOTS;
}
static inline bool already_closed(const struct nf_conn *conn)
return 0;
}
-static inline unsigned int
+static int
same_source_net(const union nf_inet_addr *addr,
const union nf_inet_addr *mask,
const union nf_inet_addr *u3, u_int8_t family)
{
if (family == NFPROTO_IPV4) {
- return (addr->ip & mask->ip) == (u3->ip & mask->ip);
+ return ntohl(addr->ip & mask->ip) -
+ ntohl(u3->ip & mask->ip);
} else {
union nf_inet_addr lh, rh;
unsigned int i;
rh.ip6[i] = u3->ip6[i] & mask->ip6[i];
}
- return memcmp(&lh.ip6, &rh.ip6, sizeof(lh.ip6)) == 0;
+ return memcmp(&lh.ip6, &rh.ip6, sizeof(lh.ip6));
}
}
-static int count_them(struct net *net,
- struct xt_connlimit_data *data,
+static bool add_hlist(struct hlist_head *head,
const struct nf_conntrack_tuple *tuple,
- const union nf_inet_addr *addr,
- const union nf_inet_addr *mask,
- u_int8_t family)
+ const union nf_inet_addr *addr)
+{
+ struct xt_connlimit_conn *conn;
+
+ conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC);
+ if (conn == NULL)
+ return false;
+ conn->tuple = *tuple;
+ conn->addr = *addr;
+ hlist_add_head(&conn->node, head);
+ return true;
+}
+
+static unsigned int check_hlist(struct net *net,
+ struct hlist_head *head,
+ const struct nf_conntrack_tuple *tuple,
+ bool *addit)
{
const struct nf_conntrack_tuple_hash *found;
struct xt_connlimit_conn *conn;
struct hlist_node *n;
struct nf_conn *found_ct;
- struct hlist_head *hash;
- bool addit = true;
- int matches = 0;
-
- if (family == NFPROTO_IPV6)
- hash = &data->iphash[connlimit_iphash6(addr, mask)];
- else
- hash = &data->iphash[connlimit_iphash(addr->ip & mask->ip)];
+ unsigned int length = 0;
+ *addit = true;
rcu_read_lock();
/* check the saved connections */
- hlist_for_each_entry_safe(conn, n, hash, node) {
+ hlist_for_each_entry_safe(conn, n, head, node) {
found = nf_conntrack_find_get(net, NF_CT_DEFAULT_ZONE,
&conn->tuple);
- found_ct = NULL;
+ if (found == NULL) {
+ hlist_del(&conn->node);
+ kmem_cache_free(connlimit_conn_cachep, conn);
+ continue;
+ }
- if (found != NULL)
- found_ct = nf_ct_tuplehash_to_ctrack(found);
+ found_ct = nf_ct_tuplehash_to_ctrack(found);
- if (found_ct != NULL &&
- nf_ct_tuple_equal(&conn->tuple, tuple) &&
- !already_closed(found_ct))
+ if (nf_ct_tuple_equal(&conn->tuple, tuple)) {
/*
* Just to be sure we have it only once in the list.
* We should not see tuples twice unless someone hooks
* this into a table without "-p tcp --syn".
*/
- addit = false;
-
- if (found == NULL) {
- /* this one is gone */
- hlist_del(&conn->node);
- kfree(conn);
- continue;
- }
-
- if (already_closed(found_ct)) {
+ *addit = false;
+ } else if (already_closed(found_ct)) {
/*
* we do not care about connections which are
* closed already -> ditch it
*/
nf_ct_put(found_ct);
hlist_del(&conn->node);
- kfree(conn);
+ kmem_cache_free(connlimit_conn_cachep, conn);
continue;
}
- if (same_source_net(addr, mask, &conn->addr, family))
- /* same source network -> be counted! */
- ++matches;
nf_ct_put(found_ct);
+ length++;
}
rcu_read_unlock();
- if (addit) {
- /* save the new connection in our list */
- conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
- if (conn == NULL)
- return -ENOMEM;
- conn->tuple = *tuple;
- conn->addr = *addr;
- hlist_add_head(&conn->node, hash);
- ++matches;
+ return length;
+}
+
+static void tree_nodes_free(struct rb_root *root,
+ struct xt_connlimit_rb *gc_nodes[],
+ unsigned int gc_count)
+{
+ struct xt_connlimit_rb *rbconn;
+
+ while (gc_count) {
+ rbconn = gc_nodes[--gc_count];
+ rb_erase(&rbconn->node, root);
+ kmem_cache_free(connlimit_rb_cachep, rbconn);
+ }
+}
+
+static unsigned int
+count_tree(struct net *net, struct rb_root *root,
+ const struct nf_conntrack_tuple *tuple,
+ const union nf_inet_addr *addr, const union nf_inet_addr *mask,
+ u8 family)
+{
+ struct xt_connlimit_rb *gc_nodes[CONNLIMIT_GC_MAX_NODES];
+ struct rb_node **rbnode, *parent;
+ struct xt_connlimit_rb *rbconn;
+ struct xt_connlimit_conn *conn;
+ unsigned int gc_count;
+ bool no_gc = false;
+
+ restart:
+ gc_count = 0;
+ parent = NULL;
+ rbnode = &(root->rb_node);
+ while (*rbnode) {
+ int diff;
+ bool addit;
+
+ rbconn = container_of(*rbnode, struct xt_connlimit_rb, node);
+
+ parent = *rbnode;
+ diff = same_source_net(addr, mask, &rbconn->addr, family);
+ if (diff < 0) {
+ rbnode = &((*rbnode)->rb_left);
+ } else if (diff > 0) {
+ rbnode = &((*rbnode)->rb_right);
+ } else {
+ /* same source network -> be counted! */
+ unsigned int count;
+ count = check_hlist(net, &rbconn->hhead, tuple, &addit);
+
+ tree_nodes_free(root, gc_nodes, gc_count);
+ if (!addit)
+ return count;
+
+ if (!add_hlist(&rbconn->hhead, tuple, addr))
+ return 0; /* hotdrop */
+
+ return count + 1;
+ }
+
+ if (no_gc || gc_count >= ARRAY_SIZE(gc_nodes))
+ continue;
+
+ /* only used for GC on hhead, retval and 'addit' ignored */
+ check_hlist(net, &rbconn->hhead, tuple, &addit);
+ if (hlist_empty(&rbconn->hhead))
+ gc_nodes[gc_count++] = rbconn;
+ }
+
+ 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;
+ }
+
+ /* no match, need to insert new node */
+ rbconn = kmem_cache_alloc(connlimit_rb_cachep, GFP_ATOMIC);
+ if (rbconn == NULL)
+ return 0;
+
+ conn = kmem_cache_alloc(connlimit_conn_cachep, GFP_ATOMIC);
+ if (conn == NULL) {
+ kmem_cache_free(connlimit_rb_cachep, rbconn);
+ return 0;
+ }
+
+ conn->tuple = *tuple;
+ conn->addr = *addr;
+ rbconn->addr = *addr;
+
+ INIT_HLIST_HEAD(&rbconn->hhead);
+ hlist_add_head(&conn->node, &rbconn->hhead);
+
+ rb_link_node(&rbconn->node, parent, rbnode);
+ rb_insert_color(&rbconn->node, root);
+ return 1;
+}
+
+static int count_them(struct net *net,
+ struct xt_connlimit_data *data,
+ const struct nf_conntrack_tuple *tuple,
+ const union nf_inet_addr *addr,
+ const union nf_inet_addr *mask,
+ u_int8_t family)
+{
+ struct rb_root *root;
+ int count;
+ u32 hash;
+
+ if (family == NFPROTO_IPV6) {
+ hash = connlimit_iphash6(addr, mask);
+ root = &data->climit_root6[hash];
+ } else {
+ hash = connlimit_iphash(addr->ip & mask->ip);
+ root = &data->climit_root4[hash];
}
- return matches;
+ spin_lock_bh(&xt_connlimit_locks[hash % CONNLIMIT_LOCK_SLOTS]);
+
+ count = count_tree(net, root, tuple, addr, mask, family);
+
+ spin_unlock_bh(&xt_connlimit_locks[hash % CONNLIMIT_LOCK_SLOTS]);
+
+ return count;
}
static bool
const struct nf_conntrack_tuple *tuple_ptr = &tuple;
enum ip_conntrack_info ctinfo;
const struct nf_conn *ct;
- int connections;
+ unsigned int connections;
ct = nf_ct_get(skb, &ctinfo);
if (ct != NULL)
iph->daddr : iph->saddr;
}
- spin_lock_bh(&info->data->lock);
connections = count_them(net, info->data, tuple_ptr, &addr,
&info->mask, par->family);
- spin_unlock_bh(&info->data->lock);
-
- if (connections < 0)
+ if (connections == 0)
/* kmalloc failed, drop it entirely */
goto hotdrop;
u_int32_t rand;
do {
- rand = prandom_u32();
+ get_random_bytes(&rand, sizeof(rand));
} while (!rand);
cmpxchg(&connlimit_rnd, 0, rand);
}
return -ENOMEM;
}
- spin_lock_init(&info->data->lock);
- for (i = 0; i < ARRAY_SIZE(info->data->iphash); ++i)
- INIT_HLIST_HEAD(&info->data->iphash[i]);
+ for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i)
+ info->data->climit_root4[i] = RB_ROOT;
+ for (i = 0; i < ARRAY_SIZE(info->data->climit_root6); ++i)
+ info->data->climit_root6[i] = RB_ROOT;
return 0;
}
-static void connlimit_mt_destroy(const struct xt_mtdtor_param *par)
+static void destroy_tree(struct rb_root *r)
{
- const struct xt_connlimit_info *info = par->matchinfo;
struct xt_connlimit_conn *conn;
+ struct xt_connlimit_rb *rbconn;
struct hlist_node *n;
- struct hlist_head *hash = info->data->iphash;
+ struct rb_node *node;
+
+ while ((node = rb_first(r)) != NULL) {
+ rbconn = container_of(node, struct xt_connlimit_rb, node);
+
+ rb_erase(node, r);
+
+ hlist_for_each_entry_safe(conn, n, &rbconn->hhead, node)
+ kmem_cache_free(connlimit_conn_cachep, conn);
+
+ kmem_cache_free(connlimit_rb_cachep, rbconn);
+ }
+}
+
+static void connlimit_mt_destroy(const struct xt_mtdtor_param *par)
+{
+ const struct xt_connlimit_info *info = par->matchinfo;
unsigned int i;
nf_ct_l3proto_module_put(par->family);
- for (i = 0; i < ARRAY_SIZE(info->data->iphash); ++i) {
- hlist_for_each_entry_safe(conn, n, &hash[i], node) {
- hlist_del(&conn->node);
- kfree(conn);
- }
- }
+ for (i = 0; i < ARRAY_SIZE(info->data->climit_root4); ++i)
+ destroy_tree(&info->data->climit_root4[i]);
+ for (i = 0; i < ARRAY_SIZE(info->data->climit_root6); ++i)
+ destroy_tree(&info->data->climit_root6[i]);
kfree(info->data);
}
static int __init connlimit_mt_init(void)
{
- return xt_register_match(&connlimit_mt_reg);
+ int ret, i;
+
+ BUILD_BUG_ON(CONNLIMIT_LOCK_SLOTS > CONNLIMIT_SLOTS);
+ BUILD_BUG_ON((CONNLIMIT_SLOTS % CONNLIMIT_LOCK_SLOTS) != 0);
+
+ for (i = 0; i < CONNLIMIT_LOCK_SLOTS; ++i)
+ spin_lock_init(&xt_connlimit_locks[i]);
+
+ connlimit_conn_cachep = kmem_cache_create("xt_connlimit_conn",
+ sizeof(struct xt_connlimit_conn),
+ 0, 0, NULL);
+ if (!connlimit_conn_cachep)
+ return -ENOMEM;
+
+ connlimit_rb_cachep = kmem_cache_create("xt_connlimit_rb",
+ sizeof(struct xt_connlimit_rb),
+ 0, 0, NULL);
+ if (!connlimit_rb_cachep) {
+ kmem_cache_destroy(connlimit_conn_cachep);
+ return -ENOMEM;
+ }
+ ret = xt_register_match(&connlimit_mt_reg);
+ if (ret != 0) {
+ kmem_cache_destroy(connlimit_conn_cachep);
+ kmem_cache_destroy(connlimit_rb_cachep);
+ }
+ return ret;
}
static void __exit connlimit_mt_exit(void)
{
xt_unregister_match(&connlimit_mt_reg);
+ kmem_cache_destroy(connlimit_conn_cachep);
+ kmem_cache_destroy(connlimit_rb_cachep);
}
module_init(connlimit_mt_init);
projects / karo-tx-linux.git / blobdiff