1 files changed, 87 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c
new file mode 100644
index 00000000..f8f0bd1a
--- /dev/null
+++ b/net/bridge/netfilter/ebt_snat.c
@@ -0,0 +1,87 @@
+/*
+ *  ebt_snat
+ *
+ *	Authors:
+ *	Bart De Schuymer <bdschuym@pandora.be>
+ *
+ *  June, 2002
+ *
+ */
+#include <linux/module.h>
+#include <net/sock.h>
+#include <linux/if_arp.h>
+#include <net/arp.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_snat_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct ebt_nat_info *info = par->targinfo;
+
+	if (!skb_make_writable(skb, 0))
+		return EBT_DROP;
+
+	memcpy(eth_hdr(skb)->h_source, info->mac, ETH_ALEN);
+	if (!(info->target & NAT_ARP_BIT) &&
+	    eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) {
+		const struct arphdr *ap;
+		struct arphdr _ah;
+
+		ap = skb_header_pointer(skb, 0, sizeof(_ah), &_ah);
+		if (ap == NULL)
+			return EBT_DROP;
+		if (ap->ar_hln != ETH_ALEN)
+			goto out;
+		if (skb_store_bits(skb, sizeof(_ah), info->mac,ETH_ALEN))
+			return EBT_DROP;
+	}
+out:
+	return info->target | ~EBT_VERDICT_BITS;
+}
+
+static int ebt_snat_tg_check(const struct xt_tgchk_param *par)
+{
+	const struct ebt_nat_info *info = par->targinfo;
+	int tmp;
+
+	tmp = info->target | ~EBT_VERDICT_BITS;
+	if (BASE_CHAIN && tmp == EBT_RETURN)
+		return -EINVAL;
+
+	if (tmp < -NUM_STANDARD_TARGETS || tmp >= 0)
+		return -EINVAL;
+	tmp = info->target | EBT_VERDICT_BITS;
+	if ((tmp & ~NAT_ARP_BIT) != ~NAT_ARP_BIT)
+		return -EINVAL;
+	return 0;
+}
+
+static struct xt_target ebt_snat_tg_reg __read_mostly = {
+	.name		= "snat",
+	.revision	= 0,
+	.family		= NFPROTO_BRIDGE,
+	.table		= "nat",
+	.hooks		= (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_POST_ROUTING),
+	.target		= ebt_snat_tg,
+	.checkentry	= ebt_snat_tg_check,
+	.targetsize	= sizeof(struct ebt_nat_info),
+	.me		= THIS_MODULE,
+};
+
+static int __init ebt_snat_init(void)
+{
+	return xt_register_target(&ebt_snat_tg_reg);
+}
+
+static void __exit ebt_snat_fini(void)
+{
+	xt_unregister_target(&ebt_snat_tg_reg);
+}
+
+module_init(ebt_snat_init);
+module_exit(ebt_snat_fini);
+MODULE_DESCRIPTION("Ebtables: Source MAC address translation");
+MODULE_LICENSE("GPL");