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 int __net_init ip6table_filter_table_init(struct net *net);
23
24 static const struct xt_table packet_filter = {
25 .name = "filter",
26 .valid_hooks = FILTER_VALID_HOOKS,
27 .me = THIS_MODULE,
28 .af = NFPROTO_IPV6,
29 .priority = NF_IP6_PRI_FILTER,
30 .table_init = ip6table_filter_table_init,
31 };
32
33 /* The work comes in here from netfilter.c. */
34 static unsigned int
ip6table_filter_hook(void * priv,struct sk_buff * skb,const struct nf_hook_state * state)35 ip6table_filter_hook(void *priv, struct sk_buff *skb,
36 const struct nf_hook_state *state)
37 {
38 return ip6t_do_table(skb, state, state->net->ipv6.ip6table_filter);
39 }
40
41 static struct nf_hook_ops *filter_ops __read_mostly;
42
43 /* Default to forward because I got too much mail already. */
44 static bool forward = true;
45 module_param(forward, bool, 0000);
46
ip6table_filter_table_init(struct net * net)47 static int __net_init ip6table_filter_table_init(struct net *net)
48 {
49 struct ip6t_replace *repl;
50 int err;
51
52 if (net->ipv6.ip6table_filter)
53 return 0;
54
55 repl = ip6t_alloc_initial_table(&packet_filter);
56 if (repl == NULL)
57 return -ENOMEM;
58 /* Entry 1 is the FORWARD hook */
59 ((struct ip6t_standard *)repl->entries)[1].target.verdict =
60 forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
61
62 err = ip6t_register_table(net, &packet_filter, repl, filter_ops,
63 &net->ipv6.ip6table_filter);
64 kfree(repl);
65 return err;
66 }
67
ip6table_filter_net_init(struct net * net)68 static int __net_init ip6table_filter_net_init(struct net *net)
69 {
70 if (net == &init_net || !forward)
71 return ip6table_filter_table_init(net);
72
73 return 0;
74 }
75
ip6table_filter_net_exit(struct net * net)76 static void __net_exit ip6table_filter_net_exit(struct net *net)
77 {
78 if (!net->ipv6.ip6table_filter)
79 return;
80 ip6t_unregister_table(net, net->ipv6.ip6table_filter, filter_ops);
81 net->ipv6.ip6table_filter = NULL;
82 }
83
84 static struct pernet_operations ip6table_filter_net_ops = {
85 .init = ip6table_filter_net_init,
86 .exit = ip6table_filter_net_exit,
87 };
88
ip6table_filter_init(void)89 static int __init ip6table_filter_init(void)
90 {
91 int ret;
92
93 filter_ops = xt_hook_ops_alloc(&packet_filter, ip6table_filter_hook);
94 if (IS_ERR(filter_ops))
95 return PTR_ERR(filter_ops);
96
97 ret = register_pernet_subsys(&ip6table_filter_net_ops);
98 if (ret < 0)
99 kfree(filter_ops);
100
101 return ret;
102 }
103
ip6table_filter_fini(void)104 static void __exit ip6table_filter_fini(void)
105 {
106 unregister_pernet_subsys(&ip6table_filter_net_ops);
107 kfree(filter_ops);
108 }
109
110 module_init(ip6table_filter_init);
111 module_exit(ip6table_filter_fini);
112