net: Add full IPv6 addresses to flow_keys

This patch adds full IPv6 addresses into flow_keys and uses them as
input to the flow hash function. The implementation supports either
IPv4 or IPv6 addresses in a union, and selector is used to determine
how may words to input to jhash2.

We also add flow_get_u32_dst and flow_get_u32_src functions which are
used to get a u32 representation of the source and destination
addresses. For IPv6, ipv6_addr_hash is called. These functions retain
getting the legacy values of src and dst in flow_keys.

With this patch, Ethertype and IP protocol are now included in the
flow hash input.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 7d0e239..77e0f0e 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -133,7 +133,7 @@
 	/* parse any remaining L2/L3 headers, check for L4 */
 	if (!skb_flow_dissect_flow_keys_buf(&keys, data, eth->h_proto,
 					    sizeof(*eth), len))
-		return max_t(u32, keys.basic.thoff, sizeof(*eth));
+		return max_t(u32, keys.control.thoff, sizeof(*eth));
 
 	/* parse for any L4 headers */
 	return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);