LXR linux/net/bridge/netfilter/ebtable

   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
  17static 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
  32static 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
  44static int check(const struct ebt_table_info *info, unsigned int valid_hooks)
  45{
  46        if (valid_hooks & ~NAT_VALID_HOOKS)
  47                return -EINVAL;
  48        return 0;
  49}
  50
  51static const struct ebt_table frame_nat = {
  52        .name           = "nat",
  53        .table          = &initial_table,
  54        .valid_hooks    = NAT_VALID_HOOKS,
  55        .check          = check,
  56        .me             = THIS_MODULE,
  57};
  58
  59static unsigned int
  60ebt_nat_in(void *priv, struct sk_buff *skb,
  61           const struct nf_hook_state *state)
  62{
  63        return ebt_do_table(skb, state, state->net->xt.frame_nat);
  64}
  65
  66static unsigned int
  67ebt_nat_out(void *priv, struct sk_buff *skb,
  68            const struct nf_hook_state *state)
  69{
  70        return ebt_do_table(skb, state, state->net->xt.frame_nat);
  71}
  72
  73static const struct nf_hook_ops ebt_ops_nat[] = {
  74        {
  75                .hook           = ebt_nat_out,
  76                .pf             = NFPROTO_BRIDGE,
  77                .hooknum        = NF_BR_LOCAL_OUT,
  78                .priority       = NF_BR_PRI_NAT_DST_OTHER,
  79        },
  80        {
  81                .hook           = ebt_nat_out,
  82                .pf             = NFPROTO_BRIDGE,
  83                .hooknum        = NF_BR_POST_ROUTING,
  84                .priority       = NF_BR_PRI_NAT_SRC,
  85        },
  86        {
  87                .hook           = ebt_nat_in,
  88                .pf             = NFPROTO_BRIDGE,
  89                .hooknum        = NF_BR_PRE_ROUTING,
  90                .priority       = NF_BR_PRI_NAT_DST_BRIDGED,
  91        },
  92};
  93
  94static int __net_init frame_nat_net_init(struct net *net)
  95{
  96        return ebt_register_table(net, &frame_nat, ebt_ops_nat,
  97                                  &net->xt.frame_nat);
  98}
  99
 100static void __net_exit frame_nat_net_exit(struct net *net)
 101{
 102        ebt_unregister_table(net, net->xt.frame_nat, ebt_ops_nat);
 103}
 104
 105static struct pernet_operations frame_nat_net_ops = {
 106        .init = frame_nat_net_init,
 107        .exit = frame_nat_net_exit,
 108};
 109
 110static int __init ebtable_nat_init(void)
 111{
 112        return register_pernet_subsys(&frame_nat_net_ops);
 113}
 114
 115static void __exit ebtable_nat_fini(void)
 116{
 117        unregister_pernet_subsys(&frame_nat_net_ops);
 118}
 119
 120module_init(ebtable_nat_init);
 121module_exit(ebtable_nat_fini);
 122MODULE_LICENSE("GPL");
 123