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(unsigned int hook, struct sk_buff *skb,
  36                      const struct net_device *in, const struct net_device *out,
  37                      int (*okfn)(struct sk_buff *))
  38 {
  39         const struct net *net = dev_net((in != NULL) ? in : out);
  40
  41         return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_filter);
  42 }
  43
  44 static struct nf_hook_ops *filter_ops __read_mostly;
  45
  46 /* Default to forward because I got too much mail already. */
  47 static int forward = NF_ACCEPT;
  48 module_param(forward, bool, 0000);
  49
  50 static int __net_init ip6table_filter_net_init(struct net *net)
  51 {
  52         struct ip6t_replace *repl;
  53
  54         repl = ip6t_alloc_initial_table(&packet_filter);
  55         if (repl == NULL)
  56                 return -ENOMEM;
  57         /* Entry 1 is the FORWARD hook */
  58         ((struct ip6t_standard *)repl->entries)[1].target.verdict =
  59                 -forward - 1;
  60
  61         net->ipv6.ip6table_filter =
  62                 ip6t_register_table(net, &packet_filter, repl);
  63         kfree(repl);
  64         if (IS_ERR(net->ipv6.ip6table_filter))
  65                 return PTR_ERR(net->ipv6.ip6table_filter);
  66         return 0;
  67 }
  68
  69 static void __net_exit ip6table_filter_net_exit(struct net *net)
  70 {
  71         ip6t_unregister_table(net, net->ipv6.ip6table_filter);
  72 }
  73
  74 static struct pernet_operations ip6table_filter_net_ops = {
  75         .init = ip6table_filter_net_init,
  76         .exit = ip6table_filter_net_exit,
  77 };
  78
  79 static int __init ip6table_filter_init(void)
  80 {
  81         int ret;
  82
  83         if (forward < 0 || forward > NF_MAX_VERDICT) {
  84                 pr_err("iptables forward must be 0 or 1\n");
  85                 return -EINVAL;
  86         }
  87
  88         ret = register_pernet_subsys(&ip6table_filter_net_ops);
  89         if (ret < 0)
  90                 return ret;
  91
  92         /* Register hooks */
  93         filter_ops = xt_hook_link(&packet_filter, ip6table_filter_hook);
  94         if (IS_ERR(filter_ops)) {
  95                 ret = PTR_ERR(filter_ops);
  96                 goto cleanup_table;
  97         }
  98
  99         return ret;
 100
 101  cleanup_table:
 102         unregister_pernet_subsys(&ip6table_filter_net_ops);
 103         return ret;
 104 }
 105
 106 static void __exit ip6table_filter_fini(void)
 107 {
 108         xt_hook_unlink(&packet_filter, filter_ops);
 109         unregister_pernet_subsys(&ip6table_filter_net_ops);
 110 }
 111
 112 module_init(ip6table_filter_init);
 113 module_exit(ip6table_filter_fini);