openvswitch: Enable retrieval of TCP flags from IPv6 traffic.

We currently check that a packet is IPv4 and TCP before fetching the
TCP flags.  This enables fetching from IPv6 packets as well.
Reported-by: Michael Mao <mmao@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

net/openvswitch/flow.c

@@ -182,7 +182,8 @@ void ovs_flow_used(struct sw_flow *flow, struct sk_buff *skb)
 {
 	u8 tcp_flags = 0;
 
-	if (flow->key.eth.type == htons(ETH_P_IP) &&
+	if ((flow->key.eth.type == htons(ETH_P_IP) ||
+	     flow->key.eth.type == htons(ETH_P_IPV6)) &&
 	    flow->key.ip.proto == IPPROTO_TCP &&
 	    likely(skb->len >= skb_transport_offset(skb) + sizeof(struct tcphdr))) {
 		u8 *tcp = (u8 *)tcp_hdr(skb);