1 /* Event cache for netfilter. */
3 /* (C) 1999-2001 Paul `Rusty' Russell
4 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/types.h>
13 #include <linux/netfilter.h>
14 #include <linux/skbuff.h>
15 #include <linux/vmalloc.h>
16 #include <linux/stddef.h>
17 #include <linux/err.h>
18 #include <linux/percpu.h>
19 #include <linux/kernel.h>
20 #include <linux/netdevice.h>
21 #include <linux/slab.h>
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_core.h>
25 #include <net/netfilter/nf_conntrack_extend.h>
27 static DEFINE_MUTEX(nf_ct_ecache_mutex);
29 struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb __read_mostly;
30 EXPORT_SYMBOL_GPL(nf_conntrack_event_cb);
32 struct nf_exp_event_notifier __rcu *nf_expect_event_cb __read_mostly;
33 EXPORT_SYMBOL_GPL(nf_expect_event_cb);
35 /* deliver cached events and clear cache entry - must be called with locally
36 * disabled softirqs */
37 void nf_ct_deliver_cached_events(struct nf_conn *ct)
40 struct nf_ct_event_notifier *notify;
41 struct nf_conntrack_ecache *e;
44 notify = rcu_dereference(nf_conntrack_event_cb);
48 e = nf_ct_ecache_find(ct);
52 events = xchg(&e->cache, 0);
54 if (nf_ct_is_confirmed(ct) && !nf_ct_is_dying(ct) && events) {
55 struct nf_ct_event item = {
61 /* We make a copy of the missed event cache without taking
62 * the lock, thus we may send missed events twice. However,
63 * this does not harm and it happens very rarely. */
64 unsigned long missed = e->missed;
66 if (!((events | missed) & e->ctmask))
69 ret = notify->fcn(events | missed, &item);
70 if (unlikely(ret < 0 || missed)) {
71 spin_lock_bh(&ct->lock);
76 spin_unlock_bh(&ct->lock);
83 EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
85 int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new)
88 struct nf_ct_event_notifier *notify;
90 mutex_lock(&nf_ct_ecache_mutex);
91 notify = rcu_dereference_protected(nf_conntrack_event_cb,
92 lockdep_is_held(&nf_ct_ecache_mutex));
97 RCU_INIT_POINTER(nf_conntrack_event_cb, new);
98 mutex_unlock(&nf_ct_ecache_mutex);
102 mutex_unlock(&nf_ct_ecache_mutex);
105 EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
107 void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new)
109 struct nf_ct_event_notifier *notify;
111 mutex_lock(&nf_ct_ecache_mutex);
112 notify = rcu_dereference_protected(nf_conntrack_event_cb,
113 lockdep_is_held(&nf_ct_ecache_mutex));
114 BUG_ON(notify != new);
115 RCU_INIT_POINTER(nf_conntrack_event_cb, NULL);
116 mutex_unlock(&nf_ct_ecache_mutex);
118 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
120 int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new)
123 struct nf_exp_event_notifier *notify;
125 mutex_lock(&nf_ct_ecache_mutex);
126 notify = rcu_dereference_protected(nf_expect_event_cb,
127 lockdep_is_held(&nf_ct_ecache_mutex));
128 if (notify != NULL) {
132 RCU_INIT_POINTER(nf_expect_event_cb, new);
133 mutex_unlock(&nf_ct_ecache_mutex);
137 mutex_unlock(&nf_ct_ecache_mutex);
140 EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
142 void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new)
144 struct nf_exp_event_notifier *notify;
146 mutex_lock(&nf_ct_ecache_mutex);
147 notify = rcu_dereference_protected(nf_expect_event_cb,
148 lockdep_is_held(&nf_ct_ecache_mutex));
149 BUG_ON(notify != new);
150 RCU_INIT_POINTER(nf_expect_event_cb, NULL);
151 mutex_unlock(&nf_ct_ecache_mutex);
153 EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);
155 #define NF_CT_EVENTS_DEFAULT 1
156 static int nf_ct_events __read_mostly = NF_CT_EVENTS_DEFAULT;
157 static int nf_ct_events_retry_timeout __read_mostly = 15*HZ;
160 static struct ctl_table event_sysctl_table[] = {
162 .procname = "nf_conntrack_events",
163 .data = &init_net.ct.sysctl_events,
164 .maxlen = sizeof(unsigned int),
166 .proc_handler = proc_dointvec,
169 .procname = "nf_conntrack_events_retry_timeout",
170 .data = &init_net.ct.sysctl_events_retry_timeout,
171 .maxlen = sizeof(unsigned int),
173 .proc_handler = proc_dointvec_jiffies,
177 #endif /* CONFIG_SYSCTL */
179 static struct nf_ct_ext_type event_extend __read_mostly = {
180 .len = sizeof(struct nf_conntrack_ecache),
181 .align = __alignof__(struct nf_conntrack_ecache),
182 .id = NF_CT_EXT_ECACHE,
186 static int nf_conntrack_event_init_sysctl(struct net *net)
188 struct ctl_table *table;
190 table = kmemdup(event_sysctl_table, sizeof(event_sysctl_table),
195 table[0].data = &net->ct.sysctl_events;
196 table[1].data = &net->ct.sysctl_events_retry_timeout;
198 net->ct.event_sysctl_header =
199 register_net_sysctl_table(net,
200 nf_net_netfilter_sysctl_path, table);
201 if (!net->ct.event_sysctl_header) {
202 printk(KERN_ERR "nf_ct_event: can't register to sysctl.\n");
213 static void nf_conntrack_event_fini_sysctl(struct net *net)
215 struct ctl_table *table;
217 table = net->ct.event_sysctl_header->ctl_table_arg;
218 unregister_net_sysctl_table(net->ct.event_sysctl_header);
222 static int nf_conntrack_event_init_sysctl(struct net *net)
227 static void nf_conntrack_event_fini_sysctl(struct net *net)
230 #endif /* CONFIG_SYSCTL */
232 int nf_conntrack_ecache_init(struct net *net)
236 net->ct.sysctl_events = nf_ct_events;
237 net->ct.sysctl_events_retry_timeout = nf_ct_events_retry_timeout;
239 if (net_eq(net, &init_net)) {
240 ret = nf_ct_extend_register(&event_extend);
242 printk(KERN_ERR "nf_ct_event: Unable to register "
243 "event extension.\n");
244 goto out_extend_register;
248 ret = nf_conntrack_event_init_sysctl(net);
255 if (net_eq(net, &init_net))
256 nf_ct_extend_unregister(&event_extend);
261 void nf_conntrack_ecache_fini(struct net *net)
263 nf_conntrack_event_fini_sysctl(net);
264 if (net_eq(net, &init_net))
265 nf_ct_extend_unregister(&event_extend);