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/* Event cache for netfilter. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/types.h>
#include <linux/netfilter.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/stddef.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
static DEFINE_MUTEX(nf_ct_ecache_mutex);
struct nf_ct_event_notifier *nf_conntrack_event_cb __read_mostly;
EXPORT_SYMBOL_GPL(nf_conntrack_event_cb);
struct nf_exp_event_notifier *nf_expect_event_cb __read_mostly;
EXPORT_SYMBOL_GPL(nf_expect_event_cb);
/* deliver cached events and clear cache entry - must be called with locally
* disabled softirqs */
static inline void
__nf_ct_deliver_cached_events(struct nf_conntrack_ecache *ecache)
{
struct nf_ct_event_notifier *notify;
rcu_read_lock();
notify = rcu_dereference(nf_conntrack_event_cb);
if (notify == NULL)
goto out_unlock;
if (nf_ct_is_confirmed(ecache->ct) && !nf_ct_is_dying(ecache->ct)
&& ecache->events) {
struct nf_ct_event item = {
.ct = ecache->ct,
.pid = 0,
.report = 0
};
notify->fcn(ecache->events, &item);
}
ecache->events = 0;
nf_ct_put(ecache->ct);
ecache->ct = NULL;
out_unlock:
rcu_read_unlock();
}
/* Deliver all cached events for a particular conntrack. This is called
* by code prior to async packet handling for freeing the skb */
void nf_ct_deliver_cached_events(const struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
struct nf_conntrack_ecache *ecache;
local_bh_disable();
ecache = per_cpu_ptr(net->ct.ecache, raw_smp_processor_id());
if (ecache->ct == ct)
__nf_ct_deliver_cached_events(ecache);
local_bh_enable();
}
EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
/* Deliver cached events for old pending events, if current conntrack != old */
void __nf_ct_event_cache_init(struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
struct nf_conntrack_ecache *ecache;
/* take care of delivering potentially old events */
ecache = per_cpu_ptr(net->ct.ecache, raw_smp_processor_id());
BUG_ON(ecache->ct == ct);
if (ecache->ct)
__nf_ct_deliver_cached_events(ecache);
/* initialize for this conntrack/packet */
ecache->ct = ct;
nf_conntrack_get(&ct->ct_general);
}
EXPORT_SYMBOL_GPL(__nf_ct_event_cache_init);
/* flush the event cache - touches other CPU's data and must not be called
* while packets are still passing through the code */
void nf_ct_event_cache_flush(struct net *net)
{
struct nf_conntrack_ecache *ecache;
int cpu;
for_each_possible_cpu(cpu) {
ecache = per_cpu_ptr(net->ct.ecache, cpu);
if (ecache->ct)
nf_ct_put(ecache->ct);
}
}
int nf_conntrack_ecache_init(struct net *net)
{
net->ct.ecache = alloc_percpu(struct nf_conntrack_ecache);
if (!net->ct.ecache)
return -ENOMEM;
return 0;
}
void nf_conntrack_ecache_fini(struct net *net)
{
free_percpu(net->ct.ecache);
}
int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new)
{
int ret = 0;
struct nf_ct_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
notify = rcu_dereference(nf_conntrack_event_cb);
if (notify != NULL) {
ret = -EBUSY;
goto out_unlock;
}
rcu_assign_pointer(nf_conntrack_event_cb, new);
mutex_unlock(&nf_ct_ecache_mutex);
return ret;
out_unlock:
mutex_unlock(&nf_ct_ecache_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new)
{
struct nf_ct_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
notify = rcu_dereference(nf_conntrack_event_cb);
BUG_ON(notify != new);
rcu_assign_pointer(nf_conntrack_event_cb, NULL);
mutex_unlock(&nf_ct_ecache_mutex);
}
EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new)
{
int ret = 0;
struct nf_exp_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
notify = rcu_dereference(nf_expect_event_cb);
if (notify != NULL) {
ret = -EBUSY;
goto out_unlock;
}
rcu_assign_pointer(nf_expect_event_cb, new);
mutex_unlock(&nf_ct_ecache_mutex);
return ret;
out_unlock:
mutex_unlock(&nf_ct_ecache_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new)
{
struct nf_exp_event_notifier *notify;
mutex_lock(&nf_ct_ecache_mutex);
notify = rcu_dereference(nf_expect_event_cb);
BUG_ON(notify != new);
rcu_assign_pointer(nf_expect_event_cb, NULL);
mutex_unlock(&nf_ct_ecache_mutex);
}
EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);
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