net: bridge: resolve forwarding path for bridge devices

Add .ndo_fill_forward_path for bridge devices.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -851,6 +851,7 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
 enum net_device_path_type {
 	DEV_PATH_ETHERNET = 0,
 	DEV_PATH_VLAN,
+	DEV_PATH_BRIDGE,
 };
 
 struct net_device_path {

net/bridge/br_device.c

@@ -385,6 +385,32 @@ static int br_del_slave(struct net_device *dev, struct net_device *slave_dev)
 	return br_del_if(br, slave_dev);
 }
 
+static int br_fill_forward_path(struct net_device_path_ctx *ctx,
+				struct net_device_path *path)
+{
+	struct net_bridge_fdb_entry *f;
+	struct net_bridge_port *dst;
+	struct net_bridge *br;
+
+	if (netif_is_bridge_port(ctx->dev))
+		return -1;
+
+	br = netdev_priv(ctx->dev);
+	f = br_fdb_find_rcu(br, ctx->daddr, 0);
+	if (!f || !f->dst)
+		return -1;
+
+	dst = READ_ONCE(f->dst);
+	if (!dst)
+		return -1;
+
+	path->type = DEV_PATH_BRIDGE;
+	path->dev = dst->br->dev;
+	ctx->dev = dst->dev;
+
+	return 0;
+}
+
 static const struct ethtool_ops br_ethtool_ops = {
 	.get_drvinfo		 = br_getinfo,
 	.get_link		 = ethtool_op_get_link,
@@ -419,6 +445,7 @@ static const struct net_device_ops br_netdev_ops = {
 	.ndo_bridge_setlink	 = br_setlink,
 	.ndo_bridge_dellink	 = br_dellink,
 	.ndo_features_check	 = passthru_features_check,
+	.ndo_fill_forward_path	 = br_fill_forward_path,
 };
 
 static struct device_type br_type = {