kernel/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         struct net *net = nf_ct_net(ct);
  39
  40         return ip6t_do_table(skb, ops->hooknum, state, net->ipv6.ip6table_nat);
  41 }
  42
  43 static unsigned int ip6table_nat_fn(const struct nf_hook_ops *ops,
  44                                     struct sk_buff *skb,
  45                                     const struct nf_hook_state *state)
  46 {
  47         return nf_nat_ipv6_fn(ops, skb, state, ip6table_nat_do_chain);
  48 }
  49
  50 static unsigned int ip6table_nat_in(const struct nf_hook_ops *ops,
  51                                     struct sk_buff *skb,
  52                                     const struct nf_hook_state *state)
  53 {
  54         return nf_nat_ipv6_in(ops, skb, state, ip6table_nat_do_chain);
  55 }
  56
  57 static unsigned int ip6table_nat_out(const struct nf_hook_ops *ops,
  58                                      struct sk_buff *skb,
  59                                      const struct nf_hook_state *state)
  60 {
  61         return nf_nat_ipv6_out(ops, skb, state, ip6table_nat_do_chain);
  62 }
  63
  64 static unsigned int ip6table_nat_local_fn(const struct nf_hook_ops *ops,
  65                                           struct sk_buff *skb,
  66                                           const struct nf_hook_state *state)
  67 {
  68         return nf_nat_ipv6_local_fn(ops, skb, state, ip6table_nat_do_chain);
  69 }
  70
  71 static struct nf_hook_ops nf_nat_ipv6_ops[] __read_mostly = {
  72         /* Before packet filtering, change destination */
  73         {
  74                 .hook           = ip6table_nat_in,
  75                 .owner          = THIS_MODULE,
  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                 .owner          = THIS_MODULE,
  84                 .pf             = NFPROTO_IPV6,
  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                 .owner          = THIS_MODULE,
  92                 .pf             = NFPROTO_IPV6,
  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                 .owner          = THIS_MODULE,
 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_net_init(struct net *net)
 107 {
 108         struct ip6t_replace *repl;
 109
 110         repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
 111         if (repl == NULL)
 112                 return -ENOMEM;
 113         net->ipv6.ip6table_nat = ip6t_register_table(net, &nf_nat_ipv6_table, repl);
 114         kfree(repl);
 115         return PTR_ERR_OR_ZERO(net->ipv6.ip6table_nat);
 116 }
 117
 118 static void __net_exit ip6table_nat_net_exit(struct net *net)
 119 {
 120         ip6t_unregister_table(net, net->ipv6.ip6table_nat);
 121 }
 122
 123 static struct pernet_operations ip6table_nat_net_ops = {
 124         .init   = ip6table_nat_net_init,
 125         .exit   = ip6table_nat_net_exit,
 126 };
 127
 128 static int __init ip6table_nat_init(void)
 129 {
 130         int err;
 131
 132         err = register_pernet_subsys(&ip6table_nat_net_ops);
 133         if (err < 0)
 134                 goto err1;
 135
 136         err = nf_register_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 137         if (err < 0)
 138                 goto err2;
 139         return 0;
 140
 141 err2:
 142         unregister_pernet_subsys(&ip6table_nat_net_ops);
 143 err1:
 144         return err;
 145 }
 146
 147 static void __exit ip6table_nat_exit(void)
 148 {
 149         nf_unregister_hooks(nf_nat_ipv6_ops, ARRAY_SIZE(nf_nat_ipv6_ops));
 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");