net/ipv6/netfilter/ip6table_filter.c

   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 <[email protected]>
   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 <[email protected]>");
  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 static struct nf_hook_ops *filter_ops __read_mostly;
  31
  32 /* Default to forward because I got too much mail already. */
  33 static bool forward = true;
  34 module_param(forward, bool, 0000);
  35
  36 static int ip6table_filter_table_init(struct net *net)
  37 {
  38         struct ip6t_replace *repl;
  39         int err;
  40
  41         repl = ip6t_alloc_initial_table(&packet_filter);
  42         if (repl == NULL)
  43                 return -ENOMEM;
  44         /* Entry 1 is the FORWARD hook */
  45         ((struct ip6t_standard *)repl->entries)[1].target.verdict =
  46                 forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
  47
  48         err = ip6t_register_table(net, &packet_filter, repl, filter_ops);
  49         kfree(repl);
  50         return err;
  51 }
  52
  53 static int __net_init ip6table_filter_net_init(struct net *net)
  54 {
  55         if (!forward)
  56                 return ip6table_filter_table_init(net);
  57
  58         return 0;
  59 }
  60
  61 static void __net_exit ip6table_filter_net_pre_exit(struct net *net)
  62 {
  63         ip6t_unregister_table_pre_exit(net, "filter");
  64 }
  65
  66 static void __net_exit ip6table_filter_net_exit(struct net *net)
  67 {
  68         ip6t_unregister_table_exit(net, "filter");
  69 }
  70
  71 static struct pernet_operations ip6table_filter_net_ops = {
  72         .init = ip6table_filter_net_init,
  73         .pre_exit = ip6table_filter_net_pre_exit,
  74         .exit = ip6table_filter_net_exit,
  75 };
  76
  77 static int __init ip6table_filter_init(void)
  78 {
  79         int ret = xt_register_template(&packet_filter,
  80                                         ip6table_filter_table_init);
  81
  82         if (ret < 0)
  83                 return ret;
  84
  85         filter_ops = xt_hook_ops_alloc(&packet_filter, ip6t_do_table);
  86         if (IS_ERR(filter_ops)) {
  87                 xt_unregister_template(&packet_filter);
  88                 return PTR_ERR(filter_ops);
  89         }
  90
  91         ret = register_pernet_subsys(&ip6table_filter_net_ops);
  92         if (ret < 0) {
  93                 xt_unregister_template(&packet_filter);
  94                 kfree(filter_ops);
  95                 return ret;
  96         }
  97
  98         return ret;
  99 }
 100
 101 static void __exit ip6table_filter_fini(void)
 102 {
 103         unregister_pernet_subsys(&ip6table_filter_net_ops);
 104         xt_unregister_template(&packet_filter);
 105         kfree(filter_ops);
 106 }
 107
 108 module_init(ip6table_filter_init);
 109 module_exit(ip6table_filter_fini);