[NET]: IPV6 checksum offloading in network devices

The existing model for checksum offload does not correctly handle
devices that can offload IPV4 and IPV6 only. The NETIF_F_HW_CSUM flag
implies device can do any arbitrary protocol.

This patch:
 * adds NETIF_F_IPV6_CSUM for those devices
 * fixes bnx2 and tg3 devices that need it
 * add NETIF_F_IPV6_CSUM to ipv6 output (incl GSO)
 * fixes assumptions about NETIF_F_ALL_CSUM in nat
 * adjusts bridge union of checksumming computation

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e7913ee..7a8f22f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -314,9 +314,10 @@
 	/* Net device features */
 	unsigned long		features;
 #define NETIF_F_SG		1	/* Scatter/gather IO. */
-#define NETIF_F_IP_CSUM		2	/* Can checksum only TCP/UDP over IPv4. */
+#define NETIF_F_IP_CSUM		2	/* Can checksum TCP/UDP over IPv4. */
 #define NETIF_F_NO_CSUM		4	/* Does not require checksum. F.e. loopack. */
 #define NETIF_F_HW_CSUM		8	/* Can checksum all the packets. */
+#define NETIF_F_IPV6_CSUM	16	/* Can checksum TCP/UDP over IPV6 */
 #define NETIF_F_HIGHDMA		32	/* Can DMA to high memory. */
 #define NETIF_F_FRAGLIST	64	/* Scatter/gather IO. */
 #define NETIF_F_HW_VLAN_TX	128	/* Transmit VLAN hw acceleration */
@@ -338,8 +339,11 @@
 	/* List of features with software fallbacks. */
 #define NETIF_F_GSO_SOFTWARE	(NETIF_F_TSO | NETIF_F_TSO_ECN | NETIF_F_TSO6)
 
+
 #define NETIF_F_GEN_CSUM	(NETIF_F_NO_CSUM | NETIF_F_HW_CSUM)
-#define NETIF_F_ALL_CSUM	(NETIF_F_IP_CSUM | NETIF_F_GEN_CSUM)
+#define NETIF_F_V4_CSUM		(NETIF_F_GEN_CSUM | NETIF_F_IP_CSUM)
+#define NETIF_F_V6_CSUM		(NETIF_F_GEN_CSUM | NETIF_F_IPV6_CSUM)
+#define NETIF_F_ALL_CSUM	(NETIF_F_V4_CSUM | NETIF_F_V6_CSUM)
 
 	struct net_device	*next_sched;