// SPDX-License-Identifier: GPL-2.0-only
/*
* ebt_dnat
*
* Authors:
* Bart De Schuymer <[email protected]>
*
* June, 2002
*
*/
#include <linux/module.h>
#include <net/sock.h>
#include "../br_private.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_action_param *par)
{
const struct ebt_nat_info *info = par->targinfo;
if (skb_ensure_writable(skb, 0))
return EBT_DROP;
ether_addr_copy(eth_hdr(skb)->h_dest, info->mac);
if (is_multicast_ether_addr(info->mac)) {
if (is_broadcast_ether_addr(info->mac))
skb->pkt_type = PACKET_BROADCAST;
else
skb->pkt_type = PACKET_MULTICAST;
} else {
const struct net_device *dev;
switch (xt_hooknum(par)) {
case NF_BR_BROUTING:
dev = xt_in(par);
break;
case NF_BR_PRE_ROUTING:
dev = br_port_get_rcu(xt_in(par))->br->dev;
break;
default:
dev = NULL;
break;
}
if (!dev) /* NF_BR_LOCAL_OUT */
return info->target;
if (ether_addr_equal(info->mac, dev->dev_addr))
skb->pkt_type = PACKET_HOST;
else
skb->pkt_type = PACKET_OTHERHOST;
}
return info->target;
}
static int 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 -EINVAL;
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 -EINVAL;
if (ebt_invalid_target(info->target))
return -EINVAL;
return 0;
}
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 = 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");