1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
4 *
5 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
6 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
7 */
8
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/netfilter_ipv6/ip6_tables.h>
12 #include <linux/slab.h>
13
14 MODULE_LICENSE("GPL");
15 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
16 MODULE_DESCRIPTION("ip6tables filter table");
17
18 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
19 (1 << NF_INET_FORWARD) | \
20 (1 << NF_INET_LOCAL_OUT))
21
22 static const struct xt_table packet_filter = {
23 .name = "filter",
24 .valid_hooks = FILTER_VALID_HOOKS,
25 .me = THIS_MODULE,
26 .af = NFPROTO_IPV6,
27 .priority = NF_IP6_PRI_FILTER,
28 };
29
30 /* The work comes in here from netfilter.c. */
31 static unsigned int
ip6table_filter_hook(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)32 ip6table_filter_hook(void *priv, struct sk_buff *skb,
33 const struct nf_hook_state *state)
34 {
35 return ip6t_do_table(skb, state, priv);
36 }
37
38 static struct nf_hook_ops *filter_ops __read_mostly;
39
40 /* Default to forward because I got too much mail already. */
41 static bool forward = true;
42 module_param(forward, bool, 0000);
43
ip6table_filter_table_init(struct net * net)44 static int ip6table_filter_table_init(struct net *net)
45 {
46 struct ip6t_replace *repl;
47 int err;
48
49 repl = ip6t_alloc_initial_table(&packet_filter);
50 if (repl == NULL)
51 return -ENOMEM;
52 /* Entry 1 is the FORWARD hook */
53 ((struct ip6t_standard *)repl->entries)[1].target.verdict =
54 forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
55
56 err = ip6t_register_table(net, &packet_filter, repl, filter_ops);
57 kfree(repl);
58 return err;
59 }
60
ip6table_filter_net_init(struct net * net)61 static int __net_init ip6table_filter_net_init(struct net *net)
62 {
63 if (!forward)
64 return ip6table_filter_table_init(net);
65
66 return 0;
67 }
68
ip6table_filter_net_pre_exit(struct net * net)69 static void __net_exit ip6table_filter_net_pre_exit(struct net *net)
70 {
71 ip6t_unregister_table_pre_exit(net, "filter");
72 }
73
ip6table_filter_net_exit(struct net * net)74 static void __net_exit ip6table_filter_net_exit(struct net *net)
75 {
76 ip6t_unregister_table_exit(net, "filter");
77 }
78
79 static struct pernet_operations ip6table_filter_net_ops = {
80 .init = ip6table_filter_net_init,
81 .pre_exit = ip6table_filter_net_pre_exit,
82 .exit = ip6table_filter_net_exit,
83 };
84
ip6table_filter_init(void)85 static int __init ip6table_filter_init(void)
86 {
87 int ret = xt_register_template(&packet_filter,
88 ip6table_filter_table_init);
89
90 if (ret < 0)
91 return ret;
92
93 filter_ops = xt_hook_ops_alloc(&packet_filter, ip6table_filter_hook);
94 if (IS_ERR(filter_ops)) {
95 xt_unregister_template(&packet_filter);
96 return PTR_ERR(filter_ops);
97 }
98
99 ret = register_pernet_subsys(&ip6table_filter_net_ops);
100 if (ret < 0) {
101 xt_unregister_template(&packet_filter);
102 kfree(filter_ops);
103 return ret;
104 }
105
106 return ret;
107 }
108
ip6table_filter_fini(void)109 static void __exit ip6table_filter_fini(void)
110 {
111 unregister_pernet_subsys(&ip6table_filter_net_ops);
112 xt_unregister_template(&packet_filter);
113 kfree(filter_ops);
114 }
115
116 module_init(ip6table_filter_init);
117 module_exit(ip6table_filter_fini);
118