kernel/net/ipv6/netfilter/ip6table_filter.c

   1 /*
   2  * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
   3  *
   4  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
   5  * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.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/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/netfilter_ipv6/ip6_tables.h>
  15 #include <linux/slab.h>
  16
  17 MODULE_LICENSE("GPL");
  18 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  19 MODULE_DESCRIPTION("ip6tables filter table");
  20
  21 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
  22                             (1 << NF_INET_FORWARD) | \
  23                             (1 << NF_INET_LOCAL_OUT))
  24
  25 static const struct xt_table packet_filter = {
  26         .name           = "filter",
  27         .valid_hooks    = FILTER_VALID_HOOKS,
  28         .me             = THIS_MODULE,
  29         .af             = NFPROTO_IPV6,
  30         .priority       = NF_IP6_PRI_FILTER,
  31 };
  32
  33 /* The work comes in here from netfilter.c. */
  34 static unsigned int
  35 ip6table_filter_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
  36                      const struct nf_hook_state *state)
  37 {
  38         const struct net *net = dev_net(state->in ? state->in : state->out);
  39
  40         return ip6t_do_table(skb, ops->hooknum, state, net->ipv6.ip6table_filter);
  41 }
  42
  43 static struct nf_hook_ops *filter_ops __read_mostly;
  44
  45 /* Default to forward because I got too much mail already. */
  46 static bool forward = true;
  47 module_param(forward, bool, 0000);
  48
  49 static int __net_init ip6table_filter_net_init(struct net *net)
  50 {
  51         struct ip6t_replace *repl;
  52
  53         repl = ip6t_alloc_initial_table(&packet_filter);
  54         if (repl == NULL)
  55                 return -ENOMEM;
  56         /* Entry 1 is the FORWARD hook */
  57         ((struct ip6t_standard *)repl->entries)[1].target.verdict =
  58                 forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
  59
  60         net->ipv6.ip6table_filter =
  61                 ip6t_register_table(net, &packet_filter, repl);
  62         kfree(repl);
  63         return PTR_ERR_OR_ZERO(net->ipv6.ip6table_filter);
  64 }
  65
  66 static void __net_exit ip6table_filter_net_exit(struct net *net)
  67 {
  68         ip6t_unregister_table(net, net->ipv6.ip6table_filter);
  69 }
  70
  71 static struct pernet_operations ip6table_filter_net_ops = {
  72         .init = ip6table_filter_net_init,
  73         .exit = ip6table_filter_net_exit,
  74 };
  75
  76 static int __init ip6table_filter_init(void)
  77 {
  78         int ret;
  79
  80         ret = register_pernet_subsys(&ip6table_filter_net_ops);
  81         if (ret < 0)
  82                 return ret;
  83
  84         /* Register hooks */
  85         filter_ops = xt_hook_link(&packet_filter, ip6table_filter_hook);
  86         if (IS_ERR(filter_ops)) {
  87                 ret = PTR_ERR(filter_ops);
  88                 goto cleanup_table;
  89         }
  90
  91         return ret;
  92
  93  cleanup_table:
  94         unregister_pernet_subsys(&ip6table_filter_net_ops);
  95         return ret;
  96 }
  97
  98 static void __exit ip6table_filter_fini(void)
  99 {
 100         xt_hook_unlink(&packet_filter, filter_ops);
 101         unregister_pernet_subsys(&ip6table_filter_net_ops);
 102 }
 103
 104 module_init(ip6table_filter_init);
 105 module_exit(ip6table_filter_fini);