1 files changed, 106 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c
new file mode 100644
index 000000000..3fda71a85
--- /dev/null
+++ b/net/bridge/netfilter/ebt_dnat.c
@@ -0,0 +1,106 @@
+// 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");