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

Queue handlers are registered/unregistered in only process context.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yasuyuki Kozakai 2007-07-07 22:40:26 -07:00 committed by David S. Miller
parent ce7663d84a
commit 585426fdc5
1 changed files with 29 additions and 23 deletions
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52
net/netfilter/nf_queue.c
View File

@ -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;
}