net/bridge/netfilter/ebtable_nat.c

   1 /*
   2  *  ebtable_nat
   3  *
   4  *      Authors:
   5  *      Bart De Schuymer <bdschuym@pandora.be>
   6  *
   7  *  April, 2002
   8  *
   9  */
  10
  11 #include <linux/netfilter_bridge/ebtables.h>
  12 #include <linux/module.h>
  13
  14 #define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
  15                          (1 << NF_BR_POST_ROUTING))
  16
  17 static struct ebt_entries initial_chains[] = {
  18         {
  19                 .name   = "PREROUTING",
  20                 .policy = EBT_ACCEPT,
  21         },
  22         {
  23                 .name   = "OUTPUT",
  24                 .policy = EBT_ACCEPT,
  25         },
  26         {
  27                 .name   = "POSTROUTING",
  28                 .policy = EBT_ACCEPT,
  29         }
  30 };
  31
  32 static struct ebt_replace_kernel initial_table = {
  33         .name           = "nat",
  34         .valid_hooks    = NAT_VALID_HOOKS,
  35         .entries_size   = 3 * sizeof(struct ebt_entries),
  36         .hook_entry     = {
  37                 [NF_BR_PRE_ROUTING]     = &initial_chains[0],
  38                 [NF_BR_LOCAL_OUT]       = &initial_chains[1],
  39                 [NF_BR_POST_ROUTING]    = &initial_chains[2],
  40         },
  41         .entries        = (char *)initial_chains,
  42 };
  43
  44 static const struct ebt_table frame_nat = {
  45         .name           = "nat",
  46         .table          = &initial_table,
  47         .valid_hooks    = NAT_VALID_HOOKS,
  48         .me             = THIS_MODULE,
  49 };
  50
  51 static unsigned int
  52 ebt_nat_in(void *priv, struct sk_buff *skb,
  53            const struct nf_hook_state *state)
  54 {
  55         return ebt_do_table(skb, state, state->net->xt.frame_nat);
  56 }
  57
  58 static unsigned int
  59 ebt_nat_out(void *priv, struct sk_buff *skb,
  60             const struct nf_hook_state *state)
  61 {
  62         return ebt_do_table(skb, state, state->net->xt.frame_nat);
  63 }
  64
  65 static const struct nf_hook_ops ebt_ops_nat[] = {
  66         {
  67                 .hook           = ebt_nat_out,
  68                 .pf             = NFPROTO_BRIDGE,
  69                 .hooknum        = NF_BR_LOCAL_OUT,
  70                 .priority       = NF_BR_PRI_NAT_DST_OTHER,
  71         },
  72         {
  73                 .hook           = ebt_nat_out,
  74                 .pf             = NFPROTO_BRIDGE,
  75                 .hooknum        = NF_BR_POST_ROUTING,
  76                 .priority       = NF_BR_PRI_NAT_SRC,
  77         },
  78         {
  79                 .hook           = ebt_nat_in,
  80                 .pf             = NFPROTO_BRIDGE,
  81                 .hooknum        = NF_BR_PRE_ROUTING,
  82                 .priority       = NF_BR_PRI_NAT_DST_BRIDGED,
  83         },
  84 };
  85
  86 static int __net_init frame_nat_net_init(struct net *net)
  87 {
  88         return ebt_register_table(net, &frame_nat, ebt_ops_nat,
  89                                   &net->xt.frame_nat);
  90 }
  91
  92 static void __net_exit frame_nat_net_exit(struct net *net)
  93 {
  94         ebt_unregister_table(net, net->xt.frame_nat, ebt_ops_nat);
  95 }
  96
  97 static struct pernet_operations frame_nat_net_ops = {
  98         .init = frame_nat_net_init,
  99         .exit = frame_nat_net_exit,
 100 };
 101
 102 static int __init ebtable_nat_init(void)
 103 {
 104         return register_pernet_subsys(&frame_nat_net_ops);
 105 }
 106
 107 static void __exit ebtable_nat_fini(void)
 108 {
 109         unregister_pernet_subsys(&frame_nat_net_ops);
 110 }
 111
 112 module_init(ebtable_nat_init);
 113 module_exit(ebtable_nat_fini);
 114 MODULE_LICENSE("GPL");