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[NETFILTER]: nf_conntrack: use RCU for conntrack helpers

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Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McHardy 2008-01-31 04:36:54 -08:00 committed by David S. Miller
parent 47d9504543
commit 58a3c9bb0c
3 changed files with 21 additions and 50 deletions
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4
include/net/netfilter/nf_conntrack_helper.h
View File

@ -42,13 +42,9 @@ struct nf_conntrack_helper
extern struct nf_conntrack_helper * extern struct nf_conntrack_helper *
__nf_ct_helper_find(const struct nf_conntrack_tuple *tuple); __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 * extern struct nf_conntrack_helper *
__nf_conntrack_helper_find_byname(const char *name); __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 int nf_conntrack_helper_register(struct nf_conntrack_helper *);
extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *); extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);

58
net/netfilter/nf_conntrack_helper.c
View File

@ -28,6 +28,7 @@
#include <net/netfilter/nf_conntrack_core.h> #include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_extend.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 struct hlist_head *nf_ct_helper_hash __read_mostly;
static unsigned int nf_ct_helper_hsize __read_mostly; static unsigned int nf_ct_helper_hsize __read_mostly;
static unsigned int nf_ct_helper_count __read_mostly; static unsigned int nf_ct_helper_count __read_mostly;
@ -54,42 +55,13 @@ __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
return NULL; return NULL;
h = helper_hash(tuple); 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)) if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
return helper; return helper;
} }
return NULL; return NULL;
} }
EXPORT_SYMBOL_GPL(__nf_ct_helper_find);
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);
struct nf_conntrack_helper * struct nf_conntrack_helper *
__nf_conntrack_helper_find_byname(const char *name) __nf_conntrack_helper_find_byname(const char *name)
@ -99,7 +71,7 @@ __nf_conntrack_helper_find_byname(const char *name)
unsigned int i; unsigned int i;
for (i = 0; i < nf_ct_helper_hsize; 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)) if (!strcmp(h->name, name))
return h; return h;
} }
@ -140,10 +112,10 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
BUG_ON(me->timeout == 0); BUG_ON(me->timeout == 0);
write_lock_bh(&nf_conntrack_lock); mutex_lock(&nf_ct_helper_mutex);
hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]); hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]);
nf_ct_helper_count++; nf_ct_helper_count++;
write_unlock_bh(&nf_conntrack_lock); mutex_unlock(&nf_ct_helper_mutex);
return 0; return 0;
} }
@ -156,10 +128,17 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
struct hlist_node *n, *next; struct hlist_node *n, *next;
unsigned int i; unsigned int i;
/* Need write lock here, to delete helper. */ mutex_lock(&nf_ct_helper_mutex);
write_lock_bh(&nf_conntrack_lock); hlist_del_rcu(&me->hnode);
hlist_del(&me->hnode);
nf_ct_helper_count--; 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 */ /* Get rid of expectations */
for (i = 0; i < nf_ct_expect_hsize; i++) { for (i = 0; i < nf_ct_expect_hsize; i++) {
@ -182,9 +161,6 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
unhelp(h, me); unhelp(h, me);
} }
write_unlock_bh(&nf_conntrack_lock); 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); EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);

9
net/netfilter/nf_conntrack_netlink.c
View File

@ -1167,11 +1167,12 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
ct->mark = ntohl(nla_get_be32(cda[CTA_MARK])); ct->mark = ntohl(nla_get_be32(cda[CTA_MARK]));
#endif #endif
helper = nf_ct_helper_find_get(rtuple); rcu_read_lock();
helper = __nf_ct_helper_find(rtuple);
if (helper) { if (helper) {
help = nf_ct_helper_ext_add(ct, GFP_KERNEL); help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
if (help == NULL) { if (help == NULL) {
nf_ct_helper_put(helper); rcu_read_unlock();
err = -ENOMEM; err = -ENOMEM;
goto err; goto err;
} }
@ -1187,9 +1188,7 @@ ctnetlink_create_conntrack(struct nlattr *cda[],
add_timer(&ct->timeout); add_timer(&ct->timeout);
nf_conntrack_hash_insert(ct); nf_conntrack_hash_insert(ct);
rcu_read_unlock();
if (helper)
nf_ct_helper_put(helper);
return 0; return 0;