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 const struct xt_table nf_nat_ipv6_table = {
  24         .name           = "nat",
  25         .valid_hooks    = (1 << NF_INET_PRE_ROUTING) |
  26                           (1 << NF_INET_POST_ROUTING) |
  27                           (1 << NF_INET_LOCAL_OUT) |
  28                           (1 << NF_INET_LOCAL_IN),
  29         .me             = THIS_MODULE,
  30         .af             = NFPROTO_IPV6,
  31 };
  32
  33 static unsigned int ip6table_nat_do_chain(void *priv,
  34                                           struct sk_buff *skb,
  35                                           const struct nf_hook_state *state,
  36                                           struct nf_conn *ct)
  37 {
  38         return ip6t_do_table(skb, state, state->net->ipv6.ip6table_nat);
  39 }
  40
  41 static unsigned int ip6table_nat_fn(void *priv,
  42                                     struct sk_buff *skb,
  43                                     const struct nf_hook_state *state)
  44 {
  45         return nf_nat_ipv6_fn(priv, skb, state, ip6table_nat_do_chain);
  46 }
  47
  48 static unsigned int ip6table_nat_in(void *priv,
  49                                     struct sk_buff *skb,
  50                                     const struct nf_hook_state *state)
  51 {
  52         return nf_nat_ipv6_in(priv, skb, state, ip6table_nat_do_chain);
  53 }
  54
  55 static unsigned int ip6table_nat_out(void *priv,
  56                                      struct sk_buff *skb,
  57                                      const struct nf_hook_state *state)
  58 {
  59         return nf_nat_ipv6_out(priv, skb, state, ip6table_nat_do_chain);
  60 }
  61
  62 static unsigned int ip6table_nat_local_fn(void *priv,
  63                                           struct sk_buff *skb,
  64                                           const struct nf_hook_state *state)
  65 {
  66         return nf_nat_ipv6_local_fn(priv, skb, state, ip6table_nat_do_chain);
  67 }
  68
  69 static struct nf_hook_ops nf_nat_ipv6_ops[] __read_mostly = {
  70         /* Before packet filtering, change destination */
  71         {
  72                 .hook           = ip6table_nat_in,
  73                 .pf             = NFPROTO_IPV6,
  74                 .hooknum        = NF_INET_PRE_ROUTING,
  75                 .priority       = NF_IP6_PRI_NAT_DST,
  76         },
  77         /* After packet filtering, change source */
  78         {
  79                 .hook           = ip6table_nat_out,
  80                 .pf             = NFPROTO_IPV6,
  81                 .hooknum        = NF_INET_POST_ROUTING,
  82                 .priority       = NF_IP6_PRI_NAT_SRC,
  83         },
  84         /* Before packet filtering, change destination */
  85         {
  86                 .hook           = ip6table_nat_local_fn,
  87                 .pf             = NFPROTO_IPV6,
  88                 .hooknum        = NF_INET_LOCAL_OUT,
  89                 .priority       = NF_IP6_PRI_NAT_DST,
  90         },
  91         /* After packet filtering, change source */
  92         {
  93                 .hook           = ip6table_nat_fn,
  94                 .pf             = NFPROTO_IPV6,
  95                 .hooknum        = NF_INET_LOCAL_IN,
  96                 .priority       = NF_IP6_PRI_NAT_SRC,
  97         },
  98 };
  99
 100 static int __net_init ip6table_nat_net_init(struct net *net)
 101 {
 102         struct ip6t_replace *repl;
 103
 104         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 105         if (repl == NULL)
 106                 return -ENOMEM;
 107         net->ipv6.ip6table_nat = ip6t_register_table(net, &nf_nat_ipv6_table, repl);
 108         kfree(repl);
 109         return PTR_ERR_OR_ZERO(net->ipv6.ip6table_nat);
 110 }
 111
 112 static void __net_exit ip6table_nat_net_exit(struct net *net)
 113 {
 114         ip6t_unregister_table(net, net->ipv6.ip6table_nat);
 115 }
 116
 117 static struct pernet_operations ip6table_nat_net_ops = {
 118         .init   = ip6table_nat_net_init,
 119         .exit   = ip6table_nat_net_exit,
 120 };
 121
 122 static int __init ip6table_nat_init(void)
 123 {
 124         int err;
 125
 126         err = register_pernet_subsys(&ip6table_nat_net_ops);
 127         if (err < 0)
 128                 goto err1;
 129
 130         err = nf_register_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 131         if (err < 0)
 132                 goto err2;
 133         return 0;
 134
 135 err2:
 136         unregister_pernet_subsys(&ip6table_nat_net_ops);
 137 err1:
 138         return err;
 139 }
 140
 141 static void __exit ip6table_nat_exit(void)
 142 {
 143         nf_unregister_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 144         unregister_pernet_subsys(&ip6table_nat_net_ops);
 145 }
 146
 147 module_init(ip6table_nat_init);
 148 module_exit(ip6table_nat_exit);
 149
 150 MODULE_LICENSE("GPL");