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 unsigned int ip6table_nat_fn(void *priv,
  44                                     struct sk_buff *skb,
  45                                     const struct nf_hook_state *state)
  46 {
  47         return nf_nat_ipv6_fn(priv, skb, state, ip6table_nat_do_chain);
  48 }
  49
  50 static unsigned int ip6table_nat_in(void *priv,
  51                                     struct sk_buff *skb,
  52                                     const struct nf_hook_state *state)
  53 {
  54         return nf_nat_ipv6_in(priv, skb, state, ip6table_nat_do_chain);
  55 }
  56
  57 static unsigned int ip6table_nat_out(void *priv,
  58                                      struct sk_buff *skb,
  59                                      const struct nf_hook_state *state)
  60 {
  61         return nf_nat_ipv6_out(priv, skb, state, ip6table_nat_do_chain);
  62 }
  63
  64 static unsigned int ip6table_nat_local_fn(void *priv,
  65                                           struct sk_buff *skb,
  66                                           const struct nf_hook_state *state)
  67 {
  68         return nf_nat_ipv6_local_fn(priv, skb, state, ip6table_nat_do_chain);
  69 }
  70
  71 static const struct nf_hook_ops nf_nat_ipv6_ops[] = {
  72         /* Before packet filtering, change destination */
  73         {
  74                 .hook           = ip6table_nat_in,
  75                 .pf             = NFPROTO_IPV6,
  76                 .nat_hook       = true,
  77                 .hooknum        = NF_INET_PRE_ROUTING,
  78                 .priority       = NF_IP6_PRI_NAT_DST,
  79         },
  80         /* After packet filtering, change source */
  81         {
  82                 .hook           = ip6table_nat_out,
  83                 .pf             = NFPROTO_IPV6,
  84                 .nat_hook       = true,
  85                 .hooknum        = NF_INET_POST_ROUTING,
  86                 .priority       = NF_IP6_PRI_NAT_SRC,
  87         },
  88         /* Before packet filtering, change destination */
  89         {
  90                 .hook           = ip6table_nat_local_fn,
  91                 .pf             = NFPROTO_IPV6,
  92                 .nat_hook       = true,
  93                 .hooknum        = NF_INET_LOCAL_OUT,
  94                 .priority       = NF_IP6_PRI_NAT_DST,
  95         },
  96         /* After packet filtering, change source */
  97         {
  98                 .hook           = ip6table_nat_fn,
  99                 .nat_hook       = true,
 100                 .pf             = NFPROTO_IPV6,
 101                 .hooknum        = NF_INET_LOCAL_IN,
 102                 .priority       = NF_IP6_PRI_NAT_SRC,
 103         },
 104 };
 105
 106 static int __net_init ip6table_nat_table_init(struct net *net)
 107 {
 108         struct ip6t_replace *repl;
 109         int ret;
 110
 111         if (net->ipv6.ip6table_nat)
 112                 return 0;
 113
 114         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 115         if (repl == NULL)
 116                 return -ENOMEM;
 117         ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl,
 118                                   nf_nat_ipv6_ops, &net->ipv6.ip6table_nat);
 119         kfree(repl);
 120         return ret;
 121 }
 122
 123 static void __net_exit ip6table_nat_net_exit(struct net *net)
 124 {
 125         if (!net->ipv6.ip6table_nat)
 126                 return;
 127         ip6t_unregister_table(net, net->ipv6.ip6table_nat, nf_nat_ipv6_ops);
 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");