root/net/bridge/netfilter/ebt_dnat.c

DEFINITIONS

1. ebt_dnat_tg
2. ebt_dnat_tg_check
3. ebt_dnat_init
4. ebt_dnat_fini

/*
 *  ebt_dnat
 *
 *      Authors:
 *      Bart De Schuymer <bdschuym@pandora.be>
 *
 *  June, 2002
 *
 */
#include <linux/module.h>
#include <net/sock.h>
#include <linux/netfilter.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_nat.h>

static unsigned int
ebt_dnat_tg(struct sk_buff *skb, const struct xt_target_param *par)
{
        const struct ebt_nat_info *info = par->targinfo;

        if (!skb_make_writable(skb, 0))
                return EBT_DROP;

        memcpy(eth_hdr(skb)->h_dest, info->mac, ETH_ALEN);
        return info->target;
}

static bool ebt_dnat_tg_check(const struct xt_tgchk_param *par)
{
        const struct ebt_nat_info *info = par->targinfo;
        unsigned int hook_mask;

        if (BASE_CHAIN && info->target == EBT_RETURN)
                return false;

        hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
        if ((strcmp(par->table, "nat") != 0 ||
            (hook_mask & ~((1 << NF_BR_PRE_ROUTING) |
            (1 << NF_BR_LOCAL_OUT)))) &&
            (strcmp(par->table, "broute") != 0 ||
            hook_mask & ~(1 << NF_BR_BROUTING)))
                return false;
        if (INVALID_TARGET)
                return false;
        return true;
}

static struct xt_target ebt_dnat_tg_reg __read_mostly = {
        .name           = "dnat",
        .revision       = 0,
        .family         = NFPROTO_BRIDGE,
        .hooks          = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
                          (1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING),
        .target         = ebt_dnat_tg,
        .checkentry     = ebt_dnat_tg_check,
        .targetsize     = XT_ALIGN(sizeof(struct ebt_nat_info)),
        .me             = THIS_MODULE,
};

static int __init ebt_dnat_init(void)
{
        return xt_register_target(&ebt_dnat_tg_reg);
}

static void __exit ebt_dnat_fini(void)
{
        xt_unregister_target(&ebt_dnat_tg_reg);
}

module_init(ebt_dnat_init);
module_exit(ebt_dnat_fini);
MODULE_DESCRIPTION("Ebtables: Destination MAC address translation");
MODULE_LICENSE("GPL");