[NETFILTER]: nf_conntrack: use RCU for conntrack helpers
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index 2f3af00..4ca125e 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -43,12 +43,8 @@
__nf_ct_helper_find(const struct nf_conntrack_tuple *tuple);
extern struct nf_conntrack_helper *
-nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
-
-extern struct nf_conntrack_helper *
__nf_conntrack_helper_find_byname(const char *name);
-extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 96aa637..42f781f 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -28,6 +28,7 @@
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_extend.h>
+static DEFINE_MUTEX(nf_ct_helper_mutex);
static struct hlist_head *nf_ct_helper_hash __read_mostly;
static unsigned int nf_ct_helper_hsize __read_mostly;
static unsigned int nf_ct_helper_count __read_mostly;
@@ -54,42 +55,13 @@
return NULL;
h = helper_hash(tuple);
- hlist_for_each_entry(helper, n, &nf_ct_helper_hash[h], hnode) {
+ hlist_for_each_entry_rcu(helper, n, &nf_ct_helper_hash[h], hnode) {
if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
return helper;
}
return NULL;
}
-
-struct nf_conntrack_helper *
-nf_ct_helper_find_get(const struct nf_conntrack_tuple *tuple)
-{
- struct nf_conntrack_helper *helper;
-
- /* need nf_conntrack_lock to assure that helper exists until
- * try_module_get() is called */
- read_lock_bh(&nf_conntrack_lock);
-
- helper = __nf_ct_helper_find(tuple);
- if (helper) {
- /* need to increase module usage count to assure helper will
- * not go away while the caller is e.g. busy putting a
- * conntrack in the hash that uses the helper */
- if (!try_module_get(helper->me))
- helper = NULL;
- }
-
- read_unlock_bh(&nf_conntrack_lock);
-
- return helper;
-}
-EXPORT_SYMBOL_GPL(nf_ct_helper_find_get);
-
-void nf_ct_helper_put(struct nf_conntrack_helper *helper)
-{
- module_put(helper->me);
-}
-EXPORT_SYMBOL_GPL(nf_ct_helper_put);
+EXPORT_SYMBOL_GPL(__nf_ct_helper_find);
struct nf_conntrack_helper *
__nf_conntrack_helper_find_byname(const char *name)
@@ -99,7 +71,7 @@
unsigned int i;
for (i = 0; i < nf_ct_helper_hsize; i++) {
- hlist_for_each_entry(h, n, &nf_ct_helper_hash[i], hnode) {
+ hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) {
if (!strcmp(h->name, name))
return h;
}
@@ -140,10 +112,10 @@
BUG_ON(me->timeout == 0);
- write_lock_bh(&nf_conntrack_lock);
- hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]);
+ mutex_lock(&nf_ct_helper_mutex);
+ hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]);
nf_ct_helper_count++;
- write_unlock_bh(&nf_conntrack_lock);
+ mutex_unlock(&nf_ct_helper_mutex);
return 0;
}
@@ -156,10 +128,17 @@
struct hlist_node *n, *next;
unsigned int i;
- /* Need write lock here, to delete helper. */
- write_lock_bh(&nf_conntrack_lock);
- hlist_del(&me->hnode);
+ mutex_lock(&nf_ct_helper_mutex);
+ hlist_del_rcu(&me->hnode);
nf_ct_helper_count--;
+ mutex_unlock(&nf_ct_helper_mutex);
+
+ /* Make sure every nothing is still using the helper unless its a
+ * connection in the hash.
+ */
+ synchronize_rcu();
+
+ write_lock_bh(&nf_conntrack_lock);
/* Get rid of expectations */
for (i = 0; i < nf_ct_expect_hsize; i++) {
@@ -182,9 +161,6 @@
unhelp(h, me);
}
write_unlock_bh(&nf_conntrack_lock);
-
- /* Someone could be still looking at the helper in a bh. */
- synchronize_net();
}
EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index bdae292..b6c0935 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1167,11 +1167,12 @@
ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
#endif
- helper = nf_ct_helper_find_get(rtuple);
+ rcu_read_lock();
+ helper = __nf_ct_helper_find(rtuple);
if (helper) {
help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
if (help == NULL) {
- nf_ct_helper_put(helper);
+ rcu_read_unlock();
err = -ENOMEM;
goto err;
}
@@ -1187,9 +1188,7 @@
add_timer(&ct->timeout);
nf_conntrack_hash_insert(ct);
-
- if (helper)
- nf_ct_helper_put(helper);
+ rcu_read_unlock();
return 0;