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Commit 58a3c9bb authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: nf_conntrack: use RCU for conntrack helpers 



Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 47d95045

include/net/netfilter/nf_conntrack_helper.h

+0 −4
Original line number Diff line number Diff line
@@ -42,13 +42,9 @@ struct nf_conntrack_helper 
extern struct nf_conntrack_helper *

__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 *);

net/netfilter/nf_conntrack_helper.c

+17 −41
Original line number Diff line number Diff line
@@ -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 @@ __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple) 
		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 @@ __nf_conntrack_helper_find_byname(const char *name) 
	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 @@ int nf_conntrack_helper_register(struct nf_conntrack_helper *me) 


	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 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) 
	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 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) 
			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);

net/netfilter/nf_conntrack_netlink.c

+4 −5
Original line number Diff line number Diff line
@@ -1167,11 +1167,12 @@ ctnetlink_create_conntrack(struct nlattr *cda[], 
		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 @@ ctnetlink_create_conntrack(struct nlattr *cda[], 


	add_timer(&ct->timeout);

	nf_conntrack_hash_insert(ct);



	if (helper)

		nf_ct_helper_put(helper);

	rcu_read_unlock();



	return 0;