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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>
#include <net/netfilter/nf_conntrack_extend.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 */
void nf_ct_deliver_cached_events(struct nf_conn *ct)
{
unsigned long events;
struct nf_ct_event_notifier *notify;
struct nf_conntrack_ecache *e;
rcu_read_lock();
notify = rcu_dereference(nf_conntrack_event_cb);
if (notify == NULL)
goto out_unlock;
e = nf_ct_ecache_find(ct);
if (e == NULL)
goto out_unlock;
events = xchg(&e->cache, 0);
if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct) && events) {
struct nf_ct_event item = {
.ct = ct,
.pid = 0,
.report = 0
};
notify->fcn(events, &item);
}
out_unlock:
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
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);
#define NF_CT_EVENTS_DEFAULT 1
static int nf_ct_events __read_mostly = NF_CT_EVENTS_DEFAULT;
#ifdef CONFIG_SYSCTL
static struct ctl_table event_sysctl_table[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_events",
.data = &init_net.ct.sysctl_events,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{}
};
#endif /* CONFIG_SYSCTL */
static struct nf_ct_ext_type event_extend __read_mostly = {
.len = sizeof(struct nf_conntrack_ecache),
.align = __alignof__(struct nf_conntrack_ecache),
.id = NF_CT_EXT_ECACHE,
};
#ifdef CONFIG_SYSCTL
static int nf_conntrack_event_init_sysctl(struct net *net)
{
struct ctl_table *table;
table = kmemdup(event_sysctl_table, sizeof(event_sysctl_table),
GFP_KERNEL);
if (!table)
goto out;
table[0].data = &net->ct.sysctl_events;
net->ct.event_sysctl_header =
register_net_sysctl_table(net,
nf_net_netfilter_sysctl_path, table);
if (!net->ct.event_sysctl_header) {
printk(KERN_ERR "nf_ct_event: can't register to sysctl.\n");
goto out_register;
}
return 0;
out_register:
kfree(table);
out:
return -ENOMEM;
}
static void nf_conntrack_event_fini_sysctl(struct net *net)
{
struct ctl_table *table;
table = net->ct.event_sysctl_header->ctl_table_arg;
unregister_net_sysctl_table(net->ct.event_sysctl_header);
kfree(table);
}
#else
static int nf_conntrack_event_init_sysctl(struct net *net)
{
return 0;
}
static void nf_conntrack_event_fini_sysctl(struct net *net)
{
}
#endif /* CONFIG_SYSCTL */
int nf_conntrack_ecache_init(struct net *net)
{
int ret;
net->ct.sysctl_events = nf_ct_events;
if (net_eq(net, &init_net)) {
ret = nf_ct_extend_register(&event_extend);
if (ret < 0) {
printk(KERN_ERR "nf_ct_event: Unable to register "
"event extension.\n");
goto out_extend_register;
}
}
ret = nf_conntrack_event_init_sysctl(net);
if (ret < 0)
goto out_sysctl;
return 0;
out_sysctl:
if (net_eq(net, &init_net))
nf_ct_extend_unregister(&event_extend);
out_extend_register:
return ret;
}
void nf_conntrack_ecache_fini(struct net *net)
{
nf_conntrack_event_fini_sysctl(net);
if (net_eq(net, &init_net))
nf_ct_extend_unregister(&event_extend);
}
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