1 files changed, 137 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebtable_broute.c b/net/bridge/netfilter/ebtable_broute.c
new file mode 100644
index 000000000..8f1925302
--- /dev/null
+++ b/net/bridge/netfilter/ebtable_broute.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  ebtable_broute
+ *
+ *	Authors:
+ *	Bart De Schuymer <bdschuym@pandora.be>
+ *
+ *  April, 2002
+ *
+ *  This table lets you choose between routing and bridging for frames
+ *  entering on a bridge enslaved nic. This table is traversed before any
+ *  other ebtables table. See net/bridge/br_input.c.
+ */
+
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/module.h>
+#include <linux/if_bridge.h>
+
+#include "../br_private.h"
+
+/* EBT_ACCEPT means the frame will be bridged
+ * EBT_DROP means the frame will be routed
+ */
+static struct ebt_entries initial_chain = {
+	.name		= "BROUTING",
+	.policy		= EBT_ACCEPT,
+};
+
+static struct ebt_replace_kernel initial_table = {
+	.name		= "broute",
+	.valid_hooks	= 1 << NF_BR_BROUTING,
+	.entries_size	= sizeof(struct ebt_entries),
+	.hook_entry	= {
+		[NF_BR_BROUTING]	= &initial_chain,
+	},
+	.entries	= (char *)&initial_chain,
+};
+
+static const struct ebt_table broute_table = {
+	.name		= "broute",
+	.table		= &initial_table,
+	.valid_hooks	= 1 << NF_BR_BROUTING,
+	.me		= THIS_MODULE,
+};
+
+static unsigned int ebt_broute(void *priv, struct sk_buff *skb,
+			       const struct nf_hook_state *s)
+{
+	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
+	struct nf_hook_state state;
+	unsigned char *dest;
+	int ret;
+
+	if (!p || p->state != BR_STATE_FORWARDING)
+		return NF_ACCEPT;
+
+	nf_hook_state_init(&state, NF_BR_BROUTING,
+			   NFPROTO_BRIDGE, s->in, NULL, NULL,
+			   s->net, NULL);
+
+	ret = ebt_do_table(priv, skb, &state);
+	if (ret != NF_DROP)
+		return ret;
+
+	/* DROP in ebtables -t broute means that the
+	 * skb should be routed, not bridged.
+	 * This is awkward, but can't be changed for compatibility
+	 * reasons.
+	 *
+	 * We map DROP to ACCEPT and set the ->br_netfilter_broute flag.
+	 */
+	BR_INPUT_SKB_CB(skb)->br_netfilter_broute = 1;
+
+	/* undo PACKET_HOST mangling done in br_input in case the dst
+	 * address matches the logical bridge but not the port.
+	 */
+	dest = eth_hdr(skb)->h_dest;
+	if (skb->pkt_type == PACKET_HOST &&
+	    !ether_addr_equal(skb->dev->dev_addr, dest) &&
+	     ether_addr_equal(p->br->dev->dev_addr, dest))
+		skb->pkt_type = PACKET_OTHERHOST;
+
+	return NF_ACCEPT;
+}
+
+static const struct nf_hook_ops ebt_ops_broute = {
+	.hook		= ebt_broute,
+	.pf		= NFPROTO_BRIDGE,
+	.hooknum	= NF_BR_PRE_ROUTING,
+	.priority	= NF_BR_PRI_FIRST,
+};
+
+static int broute_table_init(struct net *net)
+{
+	return ebt_register_table(net, &broute_table, &ebt_ops_broute);
+}
+
+static void __net_exit broute_net_pre_exit(struct net *net)
+{
+	ebt_unregister_table_pre_exit(net, "broute");
+}
+
+static void __net_exit broute_net_exit(struct net *net)
+{
+	ebt_unregister_table(net, "broute");
+}
+
+static struct pernet_operations broute_net_ops = {
+	.exit = broute_net_exit,
+	.pre_exit = broute_net_pre_exit,
+};
+
+static int __init ebtable_broute_init(void)
+{
+	int ret = ebt_register_template(&broute_table, broute_table_init);
+
+	if (ret)
+		return ret;
+
+	ret = register_pernet_subsys(&broute_net_ops);
+	if (ret) {
+		ebt_unregister_template(&broute_table);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit ebtable_broute_fini(void)
+{
+	unregister_pernet_subsys(&broute_net_ops);
+	ebt_unregister_template(&broute_table);
+}
+
+module_init(ebtable_broute_init);
+module_exit(ebtable_broute_fini);
+MODULE_LICENSE("GPL");