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(const struct nf_hook_ops *ops,
  34                                           struct sk_buff *skb,
  35                                           const struct nf_hook_state *state,
  36                                           struct nf_conn *ct)
  37 {
  38         return ip6t_do_table(skb, ops->hooknum, state,
  39                              state->net->ipv6.ip6table_nat);
  40 }
  41
  42 static unsigned int ip6table_nat_fn(const struct nf_hook_ops *ops,
  43                                     struct sk_buff *skb,
  44                                     const struct nf_hook_state *state)
  45 {
  46         return nf_nat_ipv6_fn(ops, skb, state, ip6table_nat_do_chain);
  47 }
  48
  49 static unsigned int ip6table_nat_in(const struct nf_hook_ops *ops,
  50                                     struct sk_buff *skb,
  51                                     const struct nf_hook_state *state)
  52 {
  53         return nf_nat_ipv6_in(ops, skb, state, ip6table_nat_do_chain);
  54 }
  55
  56 static unsigned int ip6table_nat_out(const struct nf_hook_ops *ops,
  57                                      struct sk_buff *skb,
  58                                      const struct nf_hook_state *state)
  59 {
  60         return nf_nat_ipv6_out(ops, skb, state, ip6table_nat_do_chain);
  61 }
  62
  63 static unsigned int ip6table_nat_local_fn(const struct nf_hook_ops *ops,
  64                                           struct sk_buff *skb,
  65                                           const struct nf_hook_state *state)
  66 {
  67         return nf_nat_ipv6_local_fn(ops, skb, state, ip6table_nat_do_chain);
  68 }
  69
  70 static struct nf_hook_ops nf_nat_ipv6_ops[] __read_mostly = {
  71         /* Before packet filtering, change destination */
  72         {
  73                 .hook           = ip6table_nat_in,
  74                 .owner          = THIS_MODULE,
  75                 .pf             = NFPROTO_IPV6,
  76                 .hooknum        = NF_INET_PRE_ROUTING,
  77                 .priority       = NF_IP6_PRI_NAT_DST,
  78         },
  79         /* After packet filtering, change source */
  80         {
  81                 .hook           = ip6table_nat_out,
  82                 .owner          = THIS_MODULE,
  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                 .owner          = THIS_MODULE,
  91                 .pf             = NFPROTO_IPV6,
  92                 .hooknum        = NF_INET_LOCAL_OUT,
  93                 .priority       = NF_IP6_PRI_NAT_DST,
  94         },
  95         /* After packet filtering, change source */
  96         {
  97                 .hook           = ip6table_nat_fn,
  98                 .owner          = THIS_MODULE,
  99                 .pf             = NFPROTO_IPV6,
 100                 .hooknum        = NF_INET_LOCAL_IN,
 101                 .priority       = NF_IP6_PRI_NAT_SRC,
 102         },
 103 };
 104
 105 static int __net_init ip6table_nat_net_init(struct net *net)
 106 {
 107         struct ip6t_replace *repl;
 108
 109         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 110         if (repl == NULL)
 111                 return -ENOMEM;
 112         net->ipv6.ip6table_nat = ip6t_register_table(net, &nf_nat_ipv6_table, repl);
 113         kfree(repl);
 114         return PTR_ERR_OR_ZERO(net->ipv6.ip6table_nat);
 115 }
 116
 117 static void __net_exit ip6table_nat_net_exit(struct net *net)
 118 {
 119         ip6t_unregister_table(net, net->ipv6.ip6table_nat);
 120 }
 121
 122 static struct pernet_operations ip6table_nat_net_ops = {
 123         .init   = ip6table_nat_net_init,
 124         .exit   = ip6table_nat_net_exit,
 125 };
 126
 127 static int __init ip6table_nat_init(void)
 128 {
 129         int err;
 130
 131         err = register_pernet_subsys(&ip6table_nat_net_ops);
 132         if (err < 0)
 133                 goto err1;
 134
 135         err = nf_register_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 136         if (err < 0)
 137                 goto err2;
 138         return 0;
 139
 140 err2:
 141         unregister_pernet_subsys(&ip6table_nat_net_ops);
 142 err1:
 143         return err;
 144 }
 145
 146 static void __exit ip6table_nat_exit(void)
 147 {
 148         nf_unregister_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 149         unregister_pernet_subsys(&ip6table_nat_net_ops);
 150 }
 151
 152 module_init(ip6table_nat_init);
 153 module_exit(ip6table_nat_exit);
 154
 155 MODULE_LICENSE("GPL");