// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ebt_dnat
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*
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* Authors:
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* Bart De Schuymer <bdschuym@pandora.be>
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*
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* June, 2002
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*
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*/
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#include <linux/module.h>
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#include <net/sock.h>
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#include "../br_private.h"
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#include <linux/netfilter.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/netfilter_bridge/ebt_nat.h>
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static unsigned int
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ebt_dnat_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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const struct ebt_nat_info *info = par->targinfo;
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if (skb_ensure_writable(skb, 0))
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return EBT_DROP;
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ether_addr_copy(eth_hdr(skb)->h_dest, info->mac);
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if (is_multicast_ether_addr(info->mac)) {
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if (is_broadcast_ether_addr(info->mac))
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skb->pkt_type = PACKET_BROADCAST;
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else
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skb->pkt_type = PACKET_MULTICAST;
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} else {
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const struct net_device *dev;
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switch (xt_hooknum(par)) {
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case NF_BR_BROUTING:
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dev = xt_in(par);
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break;
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case NF_BR_PRE_ROUTING:
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dev = br_port_get_rcu(xt_in(par))->br->dev;
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break;
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default:
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dev = NULL;
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break;
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}
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if (!dev) /* NF_BR_LOCAL_OUT */
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return info->target;
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if (ether_addr_equal(info->mac, dev->dev_addr))
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skb->pkt_type = PACKET_HOST;
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else
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skb->pkt_type = PACKET_OTHERHOST;
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}
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return info->target;
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}
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static int ebt_dnat_tg_check(const struct xt_tgchk_param *par)
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{
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const struct ebt_nat_info *info = par->targinfo;
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unsigned int hook_mask;
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if (BASE_CHAIN && info->target == EBT_RETURN)
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return -EINVAL;
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hook_mask = par->hook_mask & ~(1 << NF_BR_NUMHOOKS);
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if ((strcmp(par->table, "nat") != 0 ||
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(hook_mask & ~((1 << NF_BR_PRE_ROUTING) |
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(1 << NF_BR_LOCAL_OUT)))) &&
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(strcmp(par->table, "broute") != 0 ||
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hook_mask & ~(1 << NF_BR_BROUTING)))
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return -EINVAL;
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if (ebt_invalid_target(info->target))
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return -EINVAL;
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return 0;
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}
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static struct xt_target ebt_dnat_tg_reg __read_mostly = {
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.name = "dnat",
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.revision = 0,
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.family = NFPROTO_BRIDGE,
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.hooks = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_PRE_ROUTING) |
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(1 << NF_BR_LOCAL_OUT) | (1 << NF_BR_BROUTING),
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.target = ebt_dnat_tg,
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.checkentry = ebt_dnat_tg_check,
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.targetsize = sizeof(struct ebt_nat_info),
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.me = THIS_MODULE,
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};
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static int __init ebt_dnat_init(void)
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{
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return xt_register_target(&ebt_dnat_tg_reg);
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}
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static void __exit ebt_dnat_fini(void)
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{
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xt_unregister_target(&ebt_dnat_tg_reg);
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}
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module_init(ebt_dnat_init);
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module_exit(ebt_dnat_fini);
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MODULE_DESCRIPTION("Ebtables: Destination MAC address translation");
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MODULE_LICENSE("GPL");
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