[PATCH net-next 6/6] mpls: Add MPLS entropy label in flow_keys

[Tom Herbert <tom@herbertland.com>]

In flow dissector if an MPLS header contains an entropy label this is
saved in the new extra entropy field of flow_keys. The entropy label is
then represented in the flow hash function input.

Signed-off-by: Tom Herbert <tom@herbertland.com>
---
 include/uapi/linux/in.h   |  2 ++
 include/uapi/linux/mpls.h |  3 +++
 net/core/flow_dissector.c | 27 +++++++++++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
index 589ced0..c86f6ab 100644
--- a/include/uapi/linux/in.h
+++ b/include/uapi/linux/in.h
@@ -69,6 +69,8 @@ enum {
 #define IPPROTO_SCTP		IPPROTO_SCTP
   IPPROTO_UDPLITE = 136,	/* UDP-Lite (RFC 3828)			*/
 #define IPPROTO_UDPLITE		IPPROTO_UDPLITE
+  IPPROTO_MPLS = 137,		/* MPLS in IP (RFC 4023)		*/
+#define IPPROTO_MPLS		IPPROTO_SCTP
   IPPROTO_RAW = 255,		/* Raw IP packets			*/
 #define IPPROTO_RAW		IPPROTO_RAW
   IPPROTO_MAX
diff --git a/include/uapi/linux/mpls.h b/include/uapi/linux/mpls.h
index bc9abfe..3be9eb7 100644
--- a/include/uapi/linux/mpls.h
+++ b/include/uapi/linux/mpls.h
@@ -31,4 +31,7 @@ struct mpls_label {
 #define MPLS_LS_TTL_MASK        0x000000FF
 #define MPLS_LS_TTL_SHIFT       0
 
+/* Reserved labels */
+#define MPLS_LS_ENTROPY_IS_NEXT	7
+
 #endif /* _UAPI_MPLS_H */
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 025b91f..95c9a07 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -7,6 +7,7 @@
 #include <net/ipv6.h>
 #include <linux/igmp.h>
 #include <linux/icmp.h>
+#include <linux/mpls.h>
 #include <linux/sctp.h>
 #include <linux/dccp.h>
 #include <linux/if_tunnel.h>
@@ -169,6 +170,29 @@ ipv6:
 		flow->thoff = (u16)nhoff;
 		return true;
 	}
+	case htons(ETH_P_MPLS_UC):
+	case htons(ETH_P_MPLS_MC): {
+		struct mpls_label *hdr, _hdr[2];
+mpls:
+		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
+					   hlen, &_hdr);
+		if (!hdr)
+			return false;
+
+		if ((ntohl(hdr[0].entry) & MPLS_LS_LABEL_MASK) ==
+		    MPLS_LS_ENTROPY_IS_NEXT) {
+			flow->n_proto = proto;
+			flow->ip_proto = ip_proto;
+			flow->extra_entropy = ntohl(hdr[1].entry) &
+					      MPLS_LS_LABEL_MASK;
+			flow->thoff = (u16)nhoff;
+
+			return true;
+		} else {
+			return false;
+		}
+	}
+
 	case htons(ETH_P_FCOE):
 		flow->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
 		/* fall through */
@@ -234,6 +258,9 @@ ipv6:
 	case IPPROTO_IPV6:
 		proto = htons(ETH_P_IPV6);
 		goto ipv6;
+	case IPPROTO_MPLS:
+		proto = htons(ETH_P_MPLS_UC);
+		goto mpls;
 	default:
 		break;
 	}
-- 
1.8.1