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
  16 MODULE_LICENSE("GPL");
  17 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  18 MODULE_DESCRIPTION("ip6tables filter table");
  19
  20 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
  21                             (1 << NF_INET_FORWARD) | \
  22                             (1 << NF_INET_LOCAL_OUT))
  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 };
  31
  32 /* The work comes in here from netfilter.c. */
  33 static unsigned int
  34 ip6table_filter_hook(unsigned int hook, struct sk_buff *skb,
  35                      const struct net_device *in, const struct net_device *out,
  36                      int (*okfn)(struct sk_buff *))
  37 {
  38         const struct net *net = dev_net((in != NULL) ? in : out);
  39
  40         return ip6t_do_table(skb, hook, in, out, 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 int forward = NF_ACCEPT;
  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 - 1;
  59
  60         net->ipv6.ip6table_filter =
  61                 ip6t_register_table(net, &packet_filter, repl);
  62         kfree(repl);
  63         if (IS_ERR(net->ipv6.ip6table_filter))
  64                 return PTR_ERR(net->ipv6.ip6table_filter);
  65         return 0;
  66 }
  67
  68 static void __net_exit ip6table_filter_net_exit(struct net *net)
  69 {
  70         ip6t_unregister_table(net, net->ipv6.ip6table_filter);
  71 }
  72
  73 static struct pernet_operations ip6table_filter_net_ops = {
  74         .init = ip6table_filter_net_init,
  75         .exit = ip6table_filter_net_exit,
  76 };
  77
  78 static int __init ip6table_filter_init(void)
  79 {
  80         int ret;
  81
  82         if (forward < 0 || forward > NF_MAX_VERDICT) {
  83                 printk("iptables forward must be 0 or 1\n");
  84                 return -EINVAL;
  85         }
  86
  87         ret = register_pernet_subsys(&ip6table_filter_net_ops);
  88         if (ret < 0)
  89                 return ret;
  90
  91         /* Register hooks */
  92         filter_ops = xt_hook_link(&packet_filter, ip6table_filter_hook);
  93         if (IS_ERR(filter_ops)) {
  94                 ret = PTR_ERR(filter_ops);
  95                 goto cleanup_table;
  96         }
  97
  98         return ret;
  99
 100  cleanup_table:
 101         unregister_pernet_subsys(&ip6table_filter_net_ops);
 102         return ret;
 103 }
 104
 105 static void __exit ip6table_filter_fini(void)
 106 {
 107         xt_hook_unlink(&packet_filter, filter_ops);
 108         unregister_pernet_subsys(&ip6table_filter_net_ops);
 109 }
 110
 111 module_init(ip6table_filter_init);
 112 module_exit(ip6table_filter_fini);