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                                           struct nf_conn *ct)
  40 {
  41         return ip6t_do_table(skb, state, state->net->ipv6.ip6table_nat);
  42 }
  43
  44 static unsigned int ip6table_nat_fn(void *priv,
  45                                     struct sk_buff *skb,
  46                                     const struct nf_hook_state *state)
  47 {
  48         return nf_nat_ipv6_fn(priv, skb, state, ip6table_nat_do_chain);
  49 }
  50
  51 static unsigned int ip6table_nat_in(void *priv,
  52                                     struct sk_buff *skb,
  53                                     const struct nf_hook_state *state)
  54 {
  55         return nf_nat_ipv6_in(priv, skb, state, ip6table_nat_do_chain);
  56 }
  57
  58 static unsigned int ip6table_nat_out(void *priv,
  59                                      struct sk_buff *skb,
  60                                      const struct nf_hook_state *state)
  61 {
  62         return nf_nat_ipv6_out(priv, skb, state, ip6table_nat_do_chain);
  63 }
  64
  65 static unsigned int ip6table_nat_local_fn(void *priv,
  66                                           struct sk_buff *skb,
  67                                           const struct nf_hook_state *state)
  68 {
  69         return nf_nat_ipv6_local_fn(priv, skb, state, ip6table_nat_do_chain);
  70 }
  71
  72 static struct nf_hook_ops nf_nat_ipv6_ops[] __read_mostly = {
  73         /* Before packet filtering, change destination */
  74         {
  75                 .hook           = ip6table_nat_in,
  76                 .pf             = NFPROTO_IPV6,
  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                 .hooknum        = NF_INET_POST_ROUTING,
  85                 .priority       = NF_IP6_PRI_NAT_SRC,
  86         },
  87         /* Before packet filtering, change destination */
  88         {
  89                 .hook           = ip6table_nat_local_fn,
  90                 .pf             = NFPROTO_IPV6,
  91                 .hooknum        = NF_INET_LOCAL_OUT,
  92                 .priority       = NF_IP6_PRI_NAT_DST,
  93         },
  94         /* After packet filtering, change source */
  95         {
  96                 .hook           = ip6table_nat_fn,
  97                 .pf             = NFPROTO_IPV6,
  98                 .hooknum        = NF_INET_LOCAL_IN,
  99                 .priority       = NF_IP6_PRI_NAT_SRC,
 100         },
 101 };
 102
 103 static int __net_init ip6table_nat_table_init(struct net *net)
 104 {
 105         struct ip6t_replace *repl;
 106         int ret;
 107
 108         if (net->ipv6.ip6table_nat)
 109                 return 0;
 110
 111         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 112         if (repl == NULL)
 113                 return -ENOMEM;
 114         ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl,
 115                                   nf_nat_ipv6_ops, &net->ipv6.ip6table_nat);
 116         kfree(repl);
 117         return ret;
 118 }
 119
 120 static void __net_exit ip6table_nat_net_exit(struct net *net)
 121 {
 122         if (!net->ipv6.ip6table_nat)
 123                 return;
 124         ip6t_unregister_table(net, net->ipv6.ip6table_nat, nf_nat_ipv6_ops);
 125         net->ipv6.ip6table_nat = NULL;
 126 }
 127
 128 static struct pernet_operations ip6table_nat_net_ops = {
 129         .exit   = ip6table_nat_net_exit,
 130 };
 131
 132 static int __init ip6table_nat_init(void)
 133 {
 134         int ret = register_pernet_subsys(&ip6table_nat_net_ops);
 135
 136         if (ret)
 137                 return ret;
 138
 139         ret = ip6table_nat_table_init(&init_net);
 140         if (ret)
 141                 unregister_pernet_subsys(&ip6table_nat_net_ops);
 142         return ret;
 143 }
 144
 145 static void __exit ip6table_nat_exit(void)
 146 {
 147         unregister_pernet_subsys(&ip6table_nat_net_ops);
 148 }
 149
 150 module_init(ip6table_nat_init);
 151 module_exit(ip6table_nat_exit);
 152
 153 MODULE_LICENSE("GPL");