net/ipv6/netfilter/ip6table_nat.c

   1 /*
   2  * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Based on Rusty Russell's IPv4 NAT code. Development of IPv6 NAT
   9  * funded by Astaro.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/netfilter.h>
  14 #include <linux/netfilter_ipv6.h>
  15 #include <linux/netfilter_ipv6/ip6_tables.h>
  16 #include <linux/ipv6.h>
  17 #include <net/ipv6.h>
  18
  19 #include <net/netfilter/nf_nat.h>
  20 #include <net/netfilter/nf_nat_core.h>
  21 #include <net/netfilter/nf_nat_l3proto.h>
  22
  23 static int __net_init ip6table_nat_table_init(struct net *net);
  24
  25 static const struct xt_table nf_nat_ipv6_table = {
  26         .name           = "nat",
  27         .valid_hooks    = (1 << NF_INET_PRE_ROUTING) |
  28                           (1 << NF_INET_POST_ROUTING) |
  29                           (1 << NF_INET_LOCAL_OUT) |
  30                           (1 << NF_INET_LOCAL_IN),
  31         .me             = THIS_MODULE,
  32         .af             = NFPROTO_IPV6,
  33         .table_init     = ip6table_nat_table_init,
  34 };
  35
  36 static unsigned int ip6table_nat_do_chain(void *priv,
  37                                           struct sk_buff *skb,
  38                                           const struct nf_hook_state *state)
  39 {
  40         return ip6t_do_table(skb, state, state->net->ipv6.ip6table_nat);
  41 }
  42
  43 static const struct nf_hook_ops nf_nat_ipv6_ops[] = {
  44         {
  45                 .hook           = ip6table_nat_do_chain,
  46                 .pf             = NFPROTO_IPV6,
  47                 .hooknum        = NF_INET_PRE_ROUTING,
  48                 .priority       = NF_IP6_PRI_NAT_DST,
  49         },
  50         {
  51                 .hook           = ip6table_nat_do_chain,
  52                 .pf             = NFPROTO_IPV6,
  53                 .hooknum        = NF_INET_POST_ROUTING,
  54                 .priority       = NF_IP6_PRI_NAT_SRC,
  55         },
  56         {
  57                 .hook           = ip6table_nat_do_chain,
  58                 .pf             = NFPROTO_IPV6,
  59                 .hooknum        = NF_INET_LOCAL_OUT,
  60                 .priority       = NF_IP6_PRI_NAT_DST,
  61         },
  62         {
  63                 .hook           = ip6table_nat_do_chain,
  64                 .pf             = NFPROTO_IPV6,
  65                 .hooknum        = NF_INET_LOCAL_IN,
  66                 .priority       = NF_IP6_PRI_NAT_SRC,
  67         },
  68 };
  69
  70 static int ip6t_nat_register_lookups(struct net *net)
  71 {
  72         int i, ret;
  73
  74         for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) {
  75                 ret = nf_nat_l3proto_ipv6_register_fn(net, &nf_nat_ipv6_ops[i]);
  76                 if (ret) {
  77                         while (i)
  78                                 nf_nat_l3proto_ipv6_unregister_fn(net, &nf_nat_ipv6_ops[--i]);
  79
  80                         return ret;
  81                 }
  82         }
  83
  84         return 0;
  85 }
  86
  87 static void ip6t_nat_unregister_lookups(struct net *net)
  88 {
  89         int i;
  90
  91         for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++)
  92                 nf_nat_l3proto_ipv6_unregister_fn(net, &nf_nat_ipv6_ops[i]);
  93 }
  94
  95 static int __net_init ip6table_nat_table_init(struct net *net)
  96 {
  97         struct ip6t_replace *repl;
  98         int ret;
  99
 100         if (net->ipv6.ip6table_nat)
 101                 return 0;
 102
 103         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 104         if (repl == NULL)
 105                 return -ENOMEM;
 106         ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl,
 107                                   NULL, &net->ipv6.ip6table_nat);
 108         if (ret < 0) {
 109                 kfree(repl);
 110                 return ret;
 111         }
 112
 113         ret = ip6t_nat_register_lookups(net);
 114         if (ret < 0) {
 115                 ip6t_unregister_table(net, net->ipv6.ip6table_nat, NULL);
 116                 net->ipv6.ip6table_nat = NULL;
 117         }
 118         kfree(repl);
 119         return ret;
 120 }
 121
 122 static void __net_exit ip6table_nat_net_exit(struct net *net)
 123 {
 124         if (!net->ipv6.ip6table_nat)
 125                 return;
 126         ip6t_nat_unregister_lookups(net);
 127         ip6t_unregister_table(net, net->ipv6.ip6table_nat, NULL);
 128         net->ipv6.ip6table_nat = NULL;
 129 }
 130
 131 static struct pernet_operations ip6table_nat_net_ops = {
 132         .exit   = ip6table_nat_net_exit,
 133 };
 134
 135 static int __init ip6table_nat_init(void)
 136 {
 137         int ret = register_pernet_subsys(&ip6table_nat_net_ops);
 138
 139         if (ret)
 140                 return ret;
 141
 142         ret = ip6table_nat_table_init(&init_net);
 143         if (ret)
 144                 unregister_pernet_subsys(&ip6table_nat_net_ops);
 145         return ret;
 146 }
 147
 148 static void __exit ip6table_nat_exit(void)
 149 {
 150         unregister_pernet_subsys(&ip6table_nat_net_ops);
 151 }
 152
 153 module_init(ip6table_nat_init);
 154 module_exit(ip6table_nat_exit);
 155
 156 MODULE_LICENSE("GPL");