[PATCH v2 net-next 4/5] net: Add IPv6 flow label to flow_keys

[Tom Herbert <tom@herbertland.com>]

In flow_dissector set the flow label in flow_keys for IPv6. This also
removes the shortcircuiting of flow dissection when a non-zero label
is present, the flow label can be considered to provide additional
entropy for a hash.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 include/net/flow_keys.h   |  3 ++-
 net/core/flow_dissector.c | 15 +--------------
 2 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
index 14298e2..906d47a 100644
--- a/include/net/flow_keys.h
+++ b/include/net/flow_keys.h
@@ -26,7 +26,8 @@ struct flow_keys {
 	__be16	n_proto;
 	u8	ip_proto;
 	u8	padding;
-	u32	vlan_id:12;
+	u32	vlan_id:12,
+		flow_label:20;
 
 	union {
 		__be32 ports;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 148b989..de71e42 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -102,7 +102,6 @@ ip:
 	case htons(ETH_P_IPV6): {
 		const struct ipv6hdr *iph;
 		struct ipv6hdr _iph;
-		__be32 flow_label;
 
 ipv6:
 		iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
@@ -118,19 +117,7 @@ ipv6:
 
 		iph_to_flow_copy_v6addrs(flow, iph);
 
-		flow_label = ip6_flowlabel(iph);
-		if (flow_label) {
-			/* Awesome, IPv6 packet has a flow label so we can
-			 * use that to represent the ports without any
-			 * further dissection.
-			 */
-			flow->n_proto = proto;
-			flow->ip_proto = ip_proto;
-			flow->ports = flow_label;
-			flow->thoff = (u16)nhoff;
-
-			return true;
-		}
+		flow->flow_label = ntohl(ip6_flowlabel(iph));
 
 		break;
 	}
-- 
1.8.1