LXR linux/net/bridge/netfilter/ebt

   1/*
   2 *  ebt_dnat
   3 *
   4 *      Authors:
   5 *      Bart De Schuymer <bdschuym@pandora.be>
   6 *
   7 *  June, 2002
   8 *
   9 */
  10#include <linux/module.h>
  11#include <net/sock.h>
  12#include <linux/netfilter.h>
  13#include <linux/netfilter/x_tables.h>
  14#include <linux/netfilter_bridge/ebtables.h>
  15#include <linux/netfilter_bridge/ebt_nat.h>
  16
  17static unsigned int
  18ebt_dnat_tg(struct sk_buff *skb, const struct xt_target_param *par)
  19{
  20        const struct ebt_nat_info *info = par->targinfo;
  21
  22        if (!skb_make_writable(skb, 0))
  23                return EBT_DROP;
  24
  25        memcpy(eth_hdr(skb)->h_dest, info->mac, ETH_ALEN);
  26        return info->target;
  27}
  28
  29static bool ebt_dnat_tg_check(const struct xt_tgchk_param *par)
  30{
  31        const struct ebt_nat_info *info = par->targinfo;
  32        unsigned int hook_mask;
  33
  34        if (BASE_CHAIN && info->target == EBT_RETURN)
  35                return false;
  36
  37        hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
  38        if ((strcmp(par->table, "nat") != 0 ||
  39            (hook_mask & ~((1 << NF_BR_PRE_ROUTING) |
  40            (1 << NF_BR_LOCAL_OUT)))) &&
  41            (strcmp(par->table, "broute") != 0 ||
  42            hook_mask & ~(1 << NF_BR_BROUTING)))
  43                return false;
  44        if (INVALID_TARGET)
  45                return false;
  46        return true;
  47}
  48
  49static struct xt_target ebt_dnat_tg_reg __read_mostly = {
  50        .name           = "dnat",
  51        .revision       = 0,
  52        .family         = NFPROTO_BRIDGE,
  53        .hooks          = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
  54                          (1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING),
  55        .target         = ebt_dnat_tg,
  56        .checkentry     = ebt_dnat_tg_check,
  57        .targetsize     = XT_ALIGN(sizeof(struct ebt_nat_info)),
  58        .me             = THIS_MODULE,
  59};
  60
  61static int __init ebt_dnat_init(void)
  62{
  63        return xt_register_target(&ebt_dnat_tg_reg);
  64}
  65
  66static void __exit ebt_dnat_fini(void)
  67{
  68        xt_unregister_target(&ebt_dnat_tg_reg);
  69}
  70
  71module_init(ebt_dnat_init);
  72module_exit(ebt_dnat_fini);
  73MODULE_DESCRIPTION("Ebtables: Destination MAC address translation");
  74MODULE_LICENSE("GPL");
  75