Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6] / net / netfilter / nf_conntrack_ecache.c
1 /* Event cache for netfilter. */
2
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>
6  *
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.
10  */
11
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/notifier.h>
20 #include <linux/kernel.h>
21 #include <linux/netdevice.h>
22
23 #include <net/netfilter/nf_conntrack.h>
24 #include <net/netfilter/nf_conntrack_core.h>
25
26 ATOMIC_NOTIFIER_HEAD(nf_conntrack_chain);
27 EXPORT_SYMBOL_GPL(nf_conntrack_chain);
28
29 ATOMIC_NOTIFIER_HEAD(nf_ct_expect_chain);
30 EXPORT_SYMBOL_GPL(nf_ct_expect_chain);
31
32 /* deliver cached events and clear cache entry - must be called with locally
33  * disabled softirqs */
34 static inline void
35 __nf_ct_deliver_cached_events(struct nf_conntrack_ecache *ecache)
36 {
37         if (nf_ct_is_confirmed(ecache->ct) && !nf_ct_is_dying(ecache->ct)
38             && ecache->events) {
39                 struct nf_ct_event item = {
40                         .ct     = ecache->ct,
41                         .pid    = 0,
42                         .report = 0
43                 };
44
45                 atomic_notifier_call_chain(&nf_conntrack_chain,
46                                            ecache->events,
47                                            &item);
48         }
49
50         ecache->events = 0;
51         nf_ct_put(ecache->ct);
52         ecache->ct = NULL;
53 }
54
55 /* Deliver all cached events for a particular conntrack. This is called
56  * by code prior to async packet handling for freeing the skb */
57 void nf_ct_deliver_cached_events(const struct nf_conn *ct)
58 {
59         struct net *net = nf_ct_net(ct);
60         struct nf_conntrack_ecache *ecache;
61
62         local_bh_disable();
63         ecache = per_cpu_ptr(net->ct.ecache, raw_smp_processor_id());
64         if (ecache->ct == ct)
65                 __nf_ct_deliver_cached_events(ecache);
66         local_bh_enable();
67 }
68 EXPORT_SYMBOL_GPL(nf_ct_deliver_cached_events);
69
70 /* Deliver cached events for old pending events, if current conntrack != old */
71 void __nf_ct_event_cache_init(struct nf_conn *ct)
72 {
73         struct net *net = nf_ct_net(ct);
74         struct nf_conntrack_ecache *ecache;
75
76         /* take care of delivering potentially old events */
77         ecache = per_cpu_ptr(net->ct.ecache, raw_smp_processor_id());
78         BUG_ON(ecache->ct == ct);
79         if (ecache->ct)
80                 __nf_ct_deliver_cached_events(ecache);
81         /* initialize for this conntrack/packet */
82         ecache->ct = ct;
83         nf_conntrack_get(&ct->ct_general);
84 }
85 EXPORT_SYMBOL_GPL(__nf_ct_event_cache_init);
86
87 /* flush the event cache - touches other CPU's data and must not be called
88  * while packets are still passing through the code */
89 void nf_ct_event_cache_flush(struct net *net)
90 {
91         struct nf_conntrack_ecache *ecache;
92         int cpu;
93
94         for_each_possible_cpu(cpu) {
95                 ecache = per_cpu_ptr(net->ct.ecache, cpu);
96                 if (ecache->ct)
97                         nf_ct_put(ecache->ct);
98         }
99 }
100
101 int nf_conntrack_ecache_init(struct net *net)
102 {
103         net->ct.ecache = alloc_percpu(struct nf_conntrack_ecache);
104         if (!net->ct.ecache)
105                 return -ENOMEM;
106         return 0;
107 }
108
109 void nf_conntrack_ecache_fini(struct net *net)
110 {
111         free_percpu(net->ct.ecache);
112 }
113
114 int nf_conntrack_register_notifier(struct notifier_block *nb)
115 {
116         return atomic_notifier_chain_register(&nf_conntrack_chain, nb);
117 }
118 EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier);
119
120 int nf_conntrack_unregister_notifier(struct notifier_block *nb)
121 {
122         return atomic_notifier_chain_unregister(&nf_conntrack_chain, nb);
123 }
124 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier);
125
126 int nf_ct_expect_register_notifier(struct notifier_block *nb)
127 {
128         return atomic_notifier_chain_register(&nf_ct_expect_chain, nb);
129 }
130 EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier);
131
132 int nf_ct_expect_unregister_notifier(struct notifier_block *nb)
133 {
134         return atomic_notifier_chain_unregister(&nf_ct_expect_chain, nb);
135 }
136 EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier);