net: add new netdevice feature for offload of RX port for UDP tunnels

This adds a new netdevice feature, so that the offloading of RX port for
UDP tunnels can be disabled by the administrator on some netdevices,
using the "rx-udp_tunnel-port-offload" feature in ethtool.

This feature is set for all devices that provide ndo_udp_tunnel_add.
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdev_features.h

@@ -75,6 +75,7 @@ enum {
 	NETIF_F_HW_TC_BIT,		/* Offload TC infrastructure */
 	NETIF_F_HW_ESP_BIT,		/* Hardware ESP transformation offload */
 	NETIF_F_HW_ESP_TX_CSUM_BIT,	/* ESP with TX checksum offload */
+	NETIF_F_RX_UDP_TUNNEL_PORT_BIT, /* Offload of RX port for UDP tunnels */
 
 	/*
 	 * Add your fresh new feature above and remember to update
@@ -138,6 +139,7 @@ enum {
 #define NETIF_F_HW_TC		__NETIF_F(HW_TC)
 #define NETIF_F_HW_ESP		__NETIF_F(HW_ESP)
 #define NETIF_F_HW_ESP_TX_CSUM	__NETIF_F(HW_ESP_TX_CSUM)
+#define	NETIF_F_RX_UDP_TUNNEL_PORT  __NETIF_F(RX_UDP_TUNNEL_PORT)
 
 #define for_each_netdev_feature(mask_addr, bit)	\
 	for_each_set_bit(bit, (unsigned long *)mask_addr, NETDEV_FEATURE_COUNT)

net/core/dev.c

@@ -7530,6 +7530,12 @@ int register_netdevice(struct net_device *dev)
 	 */
 	dev->hw_features |= NETIF_F_SOFT_FEATURES;
 	dev->features |= NETIF_F_SOFT_FEATURES;
+
+	if (dev->netdev_ops->ndo_udp_tunnel_add) {
+		dev->features |= NETIF_F_RX_UDP_TUNNEL_PORT;
+		dev->hw_features |= NETIF_F_RX_UDP_TUNNEL_PORT;
+	}
+
 	dev->wanted_features = dev->features & dev->hw_features;
 
 	if (!(dev->flags & IFF_LOOPBACK))

net/core/ethtool.c

@@ -105,6 +105,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
 	[NETIF_F_HW_TC_BIT] =		 "hw-tc-offload",
 	[NETIF_F_HW_ESP_BIT] =		 "esp-hw-offload",
 	[NETIF_F_HW_ESP_TX_CSUM_BIT] =	 "esp-tx-csum-hw-offload",
+	[NETIF_F_RX_UDP_TUNNEL_PORT_BIT] =	 "rx-udp_tunnel-port-offload",
 };
 
 static const char