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Commit 585426fd authored by Yasuyuki Kozakai's avatar Yasuyuki Kozakai Committed by David S. Miller
Browse files

[NETFILTER]: nf_queue: Use RCU and mutex for queue handlers 



Queue handlers are registered/unregistered in only process context.

Signed-off-by: default avatarYasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ce7663d8

net/netfilter/nf_queue.c

+29 −23
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 
 */

static struct nf_queue_handler *queue_handler[NPROTO];



static DEFINE_RWLOCK(queue_handler_lock);

static DEFINE_MUTEX(queue_handler_mutex);



/* return EBUSY when somebody else is registered, return EEXIST if the

 * same handler is registered, return 0 in case of success. */
@@ -28,16 +28,16 @@ int nf_register_queue_handler(int pf, struct nf_queue_handler *qh) 
	if (pf >= NPROTO)

		return -EINVAL;



	write_lock_bh(&queue_handler_lock);

	mutex_lock(&queue_handler_mutex);

	if (queue_handler[pf] == qh)

		ret = -EEXIST;

	else if (queue_handler[pf])

		ret = -EBUSY;

	else {

		queue_handler[pf] = qh;

		rcu_assign_pointer(queue_handler[pf], qh);

		ret = 0;

	}

	write_unlock_bh(&queue_handler_lock);

	mutex_unlock(&queue_handler_mutex);



	return ret;

}
@@ -49,14 +49,16 @@ int nf_unregister_queue_handler(int pf, struct nf_queue_handler *qh) 
	if (pf >= NPROTO)

		return -EINVAL;



	write_lock_bh(&queue_handler_lock);

	mutex_lock(&queue_handler_mutex);

	if (queue_handler[pf] != qh) {

		write_unlock_bh(&queue_handler_lock);

		mutex_unlock(&queue_handler_mutex);

		return -EINVAL;

	}



	queue_handler[pf] = NULL;

	write_unlock_bh(&queue_handler_lock);

	rcu_assign_pointer(queue_handler[pf], NULL);

	mutex_unlock(&queue_handler_mutex);



	synchronize_rcu();



	return 0;

}
@@ -66,12 +68,14 @@ void nf_unregister_queue_handlers(struct nf_queue_handler *qh) 
{

	int pf;



	write_lock_bh(&queue_handler_lock);

	mutex_lock(&queue_handler_mutex);

	for (pf = 0; pf < NPROTO; pf++)  {

		if (queue_handler[pf] == qh)

			queue_handler[pf] = NULL;

			rcu_assign_pointer(queue_handler[pf], NULL);

	}

	write_unlock_bh(&queue_handler_lock);

	mutex_unlock(&queue_handler_mutex);



	synchronize_rcu();

}

EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers);
@@ -94,18 +98,21 @@ static int __nf_queue(struct sk_buff *skb, 
	struct net_device *physoutdev = NULL;

#endif

	struct nf_afinfo *afinfo;

	struct nf_queue_handler *qh;



	/* QUEUE == DROP if noone is waiting, to be safe. */

	read_lock(&queue_handler_lock);

	if (!queue_handler[pf]) {

		read_unlock(&queue_handler_lock);

	rcu_read_lock();



	qh = rcu_dereference(queue_handler[pf]);

	if (!qh) {

		rcu_read_unlock();

		kfree_skb(skb);

		return 1;

	}



	afinfo = nf_get_afinfo(pf);

	if (!afinfo) {

		read_unlock(&queue_handler_lock);

		rcu_read_unlock();

		kfree_skb(skb);

		return 1;

	}
@@ -115,7 +122,7 @@ static int __nf_queue(struct sk_buff *skb, 
		if (net_ratelimit())

			printk(KERN_ERR "OOM queueing packet %p\n",

			       skb);

		read_unlock(&queue_handler_lock);

		rcu_read_unlock();

		kfree_skb(skb);

		return 1;

	}
@@ -125,7 +132,7 @@ static int __nf_queue(struct sk_buff *skb, 


	/* If it's going away, ignore hook. */

	if (!try_module_get(info->elem->owner)) {

		read_unlock(&queue_handler_lock);

		rcu_read_unlock();

		kfree(info);

		return 0;

	}
@@ -143,10 +150,9 @@ static int __nf_queue(struct sk_buff *skb, 
	}

#endif

	afinfo->saveroute(skb, info);

	status = queue_handler[pf]->outfn(skb, info, queuenum,

					  queue_handler[pf]->data);

	status = qh->outfn(skb, info, queuenum, qh->data);



	read_unlock(&queue_handler_lock);

	rcu_read_unlock();



	if (status < 0) {

		/* James M doesn't say fuck enough. */
@@ -313,13 +319,13 @@ static int seq_show(struct seq_file *s, void *v) 
	loff_t *pos = v;

	struct nf_queue_handler *qh;



	read_lock_bh(&queue_handler_lock);

	qh = queue_handler[*pos];

	rcu_read_lock();

	qh = rcu_dereference(queue_handler[*pos]);

	if (!qh)

		ret = seq_printf(s, "%2lld NONE\n", *pos);

	else

		ret = seq_printf(s, "%2lld %s\n", *pos, qh->name);

	read_unlock_bh(&queue_handler_lock);

	rcu_read_unlock();



	return ret;

}