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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * ebt_dnat
- *
- * Authors:
- * Bart De Schuymer <bdschuym@pandora.be>
- *
- * 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");
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