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