[PATCH v4 net-next 11/11] 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 keyid 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/net/flow_dissector.h |  1 +
 net/core/flow_dissector.c    | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index f9a3084..65db4eb 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -118,6 +118,7 @@ enum flow_dissector_key_id {
 	FLOW_DISSECTOR_KEY_VLANID, /* struct flow_dissector_key_flow_tags */
 	FLOW_DISSECTOR_KEY_FLOW_LABEL, /* struct flow_dissector_key_flow_label */
 	FLOW_DISSECTOR_KEY_GRE_KEYID, /* struct flow_dissector_key_keyid */
+	FLOW_DISSECTOR_KEY_MPLS_ENTROPY, /* struct flow_dissector_key_keyid */
 
 	FLOW_DISSECTOR_KEY_MAX,
 };
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 20ce55d..da4e895 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -15,6 +15,7 @@
 #include <linux/ppp_defs.h>
 #include <linux/stddef.h>
 #include <linux/if_ether.h>
+#include <linux/mpls.h>
 #include <net/flow_dissector.h>
 #include <scsi/fc/fc_fcoe.h>
 
@@ -286,6 +287,39 @@ ipv6:
 		}
 		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_LABEL_ENTROPY) {
+			if (skb_flow_dissector_uses_key(
+					flow_dissector,
+					FLOW_DISSECTOR_KEY_MPLS_ENTROPY)) {
+				key_keyid = skb_flow_dissector_target(
+					flow_dissector,
+					FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
+					target_container);
+				key_keyid->keyid = ntohl(hdr[1].entry) &
+					MPLS_LS_LABEL_MASK;
+			}
+
+			key_basic->n_proto = proto;
+			key_basic->ip_proto = ip_proto;
+			key_control->thoff = (u16)nhoff;
+
+			return true;
+		}
+
+		return true;
+	}
+
 	case htons(ETH_P_FCOE):
 		key_control->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
 		/* fall through */
@@ -356,6 +390,9 @@ 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