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 net_device *in,
  36                                           const struct net_device *out,
  37                                           struct nf_conn *ct)
  38 {
  39         struct net *net = nf_ct_net(ct);
  40
  41         return ip6t_do_table(skb, ops->hooknum, in, out, net->ipv6.ip6table_nat);
  42 }
  43
  44 static unsigned int ip6table_nat_fn(const struct nf_hook_ops *ops,
  45                                     struct sk_buff *skb,
  46                                     const struct net_device *in,
  47                                     const struct net_device *out,
  48                                     int (*okfn)(struct sk_buff *))
  49 {
  50         return nf_nat_ipv6_fn(ops, skb, in, out, ip6table_nat_do_chain);
  51 }
  52
  53 static unsigned int ip6table_nat_in(const struct nf_hook_ops *ops,
  54                                     struct sk_buff *skb,
  55                                     const struct net_device *in,
  56                                     const struct net_device *out,
  57                                     int (*okfn)(struct sk_buff *))
  58 {
  59         return nf_nat_ipv6_in(ops, skb, in, out, ip6table_nat_do_chain);
  60 }
  61
  62 static unsigned int ip6table_nat_out(const struct nf_hook_ops *ops,
  63                                      struct sk_buff *skb,
  64                                      const struct net_device *in,
  65                                      const struct net_device *out,
  66                                      int (*okfn)(struct sk_buff *))
  67 {
  68         return nf_nat_ipv6_out(ops, skb, in, out, ip6table_nat_do_chain);
  69 }
  70
  71 static unsigned int ip6table_nat_local_fn(const struct nf_hook_ops *ops,
  72                                           struct sk_buff *skb,
  73                                           const struct net_device *in,
  74                                           const struct net_device *out,
  75                                           int (*okfn)(struct sk_buff *))
  76 {
  77         return nf_nat_ipv6_local_fn(ops, skb, in, out, ip6table_nat_do_chain);
  78 }
  79
  80 static struct nf_hook_ops nf_nat_ipv6_ops[] __read_mostly = {
  81         /* Before packet filtering, change destination */
  82         {
  83                 .hook           = ip6table_nat_in,
  84                 .owner          = THIS_MODULE,
  85                 .pf             = NFPROTO_IPV6,
  86                 .hooknum        = NF_INET_PRE_ROUTING,
  87                 .priority       = NF_IP6_PRI_NAT_DST,
  88         },
  89         /* After packet filtering, change source */
  90         {
  91                 .hook           = ip6table_nat_out,
  92                 .owner          = THIS_MODULE,
  93                 .pf             = NFPROTO_IPV6,
  94                 .hooknum        = NF_INET_POST_ROUTING,
  95                 .priority       = NF_IP6_PRI_NAT_SRC,
  96         },
  97         /* Before packet filtering, change destination */
  98         {
  99                 .hook           = ip6table_nat_local_fn,
 100                 .owner          = THIS_MODULE,
 101                 .pf             = NFPROTO_IPV6,
 102                 .hooknum        = NF_INET_LOCAL_OUT,
 103                 .priority       = NF_IP6_PRI_NAT_DST,
 104         },
 105         /* After packet filtering, change source */
 106         {
 107                 .hook           = ip6table_nat_fn,
 108                 .owner          = THIS_MODULE,
 109                 .pf             = NFPROTO_IPV6,
 110                 .hooknum        = NF_INET_LOCAL_IN,
 111                 .priority       = NF_IP6_PRI_NAT_SRC,
 112         },
 113 };
 114
 115 static int __net_init ip6table_nat_net_init(struct net *net)
 116 {
 117         struct ip6t_replace *repl;
 118
 119         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 120         if (repl == NULL)
 121                 return -ENOMEM;
 122         net->ipv6.ip6table_nat = ip6t_register_table(net, &nf_nat_ipv6_table, repl);
 123         kfree(repl);
 124         return PTR_ERR_OR_ZERO(net->ipv6.ip6table_nat);
 125 }
 126
 127 static void __net_exit ip6table_nat_net_exit(struct net *net)
 128 {
 129         ip6t_unregister_table(net, net->ipv6.ip6table_nat);
 130 }
 131
 132 static struct pernet_operations ip6table_nat_net_ops = {
 133         .init   = ip6table_nat_net_init,
 134         .exit   = ip6table_nat_net_exit,
 135 };
 136
 137 static int __init ip6table_nat_init(void)
 138 {
 139         int err;
 140
 141         err = register_pernet_subsys(&ip6table_nat_net_ops);
 142         if (err < 0)
 143                 goto err1;
 144
 145         err = nf_register_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 146         if (err < 0)
 147                 goto err2;
 148         return 0;
 149
 150 err2:
 151         unregister_pernet_subsys(&ip6table_nat_net_ops);
 152 err1:
 153         return err;
 154 }
 155
 156 static void __exit ip6table_nat_exit(void)
 157 {
 158         nf_unregister_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 159         unregister_pernet_subsys(&ip6table_nat_net_ops);
 160 }
 161
 162 module_init(ip6table_nat_init);
 163 module_exit(ip6table_nat_exit);
 164
 165 MODULE_LICENSE("GPL");