netfilter: flowtable: add dsa support

Replace the master ethernet device by the dsa slave port. Packets coming
in from the software ingress path use the dsa slave port as input
device.

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

net/netfilter/nft_flow_offload.c

@@ -89,6 +89,7 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 		path = &stack->path[i];
 		switch (path->type) {
 		case DEV_PATH_ETHERNET:
+		case DEV_PATH_DSA:
 		case DEV_PATH_VLAN:
 		case DEV_PATH_PPPOE:
 			info->indev = path->dev;
@@ -97,6 +98,10 @@ static void nft_dev_path_info(const struct net_device_path_stack *stack,
 
 			if (path->type == DEV_PATH_ETHERNET)
 				break;
+			if (path->type == DEV_PATH_DSA) {
+				i = stack->num_paths;
+				break;
+			}
 
 			/* DEV_PATH_VLAN and DEV_PATH_PPPOE */
 			if (info->num_encaps >= NF_FLOW_TABLE_ENCAP_MAX) {