[NETFILTER]: arp_tables: per-netns arp_tables FILTER
[linux-2.6.git] / net / ipv4 / netfilter / arptable_filter.c
1 /*
2  * Filtering ARP tables module.
3  *
4  * Copyright (C) 2002 David S. Miller (davem@redhat.com)
5  *
6  */
7
8 #include <linux/module.h>
9 #include <linux/netfilter_arp/arp_tables.h>
10
11 MODULE_LICENSE("GPL");
12 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
13 MODULE_DESCRIPTION("arptables filter table");
14
15 #define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
16                            (1 << NF_ARP_FORWARD))
17
18 static struct
19 {
20         struct arpt_replace repl;
21         struct arpt_standard entries[3];
22         struct arpt_error term;
23 } initial_table __net_initdata = {
24         .repl = {
25                 .name = "filter",
26                 .valid_hooks = FILTER_VALID_HOOKS,
27                 .num_entries = 4,
28                 .size = sizeof(struct arpt_standard) * 3 + sizeof(struct arpt_error),
29                 .hook_entry = {
30                         [NF_ARP_IN] = 0,
31                         [NF_ARP_OUT] = sizeof(struct arpt_standard),
32                         [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
33                 },
34                 .underflow = {
35                         [NF_ARP_IN] = 0,
36                         [NF_ARP_OUT] = sizeof(struct arpt_standard),
37                         [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
38                 },
39         },
40         .entries = {
41                 ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_IN */
42                 ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_OUT */
43                 ARPT_STANDARD_INIT(NF_ACCEPT),  /* ARP_FORWARD */
44         },
45         .term = ARPT_ERROR_INIT,
46 };
47
48 static struct arpt_table packet_filter = {
49         .name           = "filter",
50         .valid_hooks    = FILTER_VALID_HOOKS,
51         .lock           = RW_LOCK_UNLOCKED,
52         .private        = NULL,
53         .me             = THIS_MODULE,
54         .af             = NF_ARP,
55 };
56
57 /* The work comes in here from netfilter.c */
58 static unsigned int arpt_hook(unsigned int hook,
59                               struct sk_buff *skb,
60                               const struct net_device *in,
61                               const struct net_device *out,
62                               int (*okfn)(struct sk_buff *))
63 {
64         return arpt_do_table(skb, hook, in, out, init_net.ipv4.arptable_filter);
65 }
66
67 static struct nf_hook_ops arpt_ops[] __read_mostly = {
68         {
69                 .hook           = arpt_hook,
70                 .owner          = THIS_MODULE,
71                 .pf             = NF_ARP,
72                 .hooknum        = NF_ARP_IN,
73         },
74         {
75                 .hook           = arpt_hook,
76                 .owner          = THIS_MODULE,
77                 .pf             = NF_ARP,
78                 .hooknum        = NF_ARP_OUT,
79         },
80         {
81                 .hook           = arpt_hook,
82                 .owner          = THIS_MODULE,
83                 .pf             = NF_ARP,
84                 .hooknum        = NF_ARP_FORWARD,
85         },
86 };
87
88 static int __net_init arptable_filter_net_init(struct net *net)
89 {
90         /* Register table */
91         net->ipv4.arptable_filter =
92                 arpt_register_table(net, &packet_filter, &initial_table.repl);
93         if (IS_ERR(net->ipv4.arptable_filter))
94                 return PTR_ERR(net->ipv4.arptable_filter);
95         return 0;
96 }
97
98 static void __net_exit arptable_filter_net_exit(struct net *net)
99 {
100         arpt_unregister_table(net->ipv4.arptable_filter);
101 }
102
103 static struct pernet_operations arptable_filter_net_ops = {
104         .init = arptable_filter_net_init,
105         .exit = arptable_filter_net_exit,
106 };
107
108 static int __init arptable_filter_init(void)
109 {
110         int ret;
111
112         ret = register_pernet_subsys(&arptable_filter_net_ops);
113         if (ret < 0)
114                 return ret;
115
116         ret = nf_register_hooks(arpt_ops, ARRAY_SIZE(arpt_ops));
117         if (ret < 0)
118                 goto cleanup_table;
119         return ret;
120
121 cleanup_table:
122         unregister_pernet_subsys(&arptable_filter_net_ops);
123         return ret;
124 }
125
126 static void __exit arptable_filter_fini(void)
127 {
128         nf_unregister_hooks(arpt_ops, ARRAY_SIZE(arpt_ops));
129         unregister_pernet_subsys(&arptable_filter_net_ops);
130 }
131
132 module_init(arptable_filter_init);
133 module_exit(arptable_filter_fini);