ONOS-2581 Add codec for tunnel id

Change-Id: I6ff456b0419b427945cc53fb74fd0a91cdfa758e
diff --git a/core/common/src/main/java/org/onosproject/codec/impl/DecodeInstructionCodecHelper.java b/core/common/src/main/java/org/onosproject/codec/impl/DecodeInstructionCodecHelper.java
index 21968c2..568fa76 100644
--- a/core/common/src/main/java/org/onosproject/codec/impl/DecodeInstructionCodecHelper.java
+++ b/core/common/src/main/java/org/onosproject/codec/impl/DecodeInstructionCodecHelper.java
@@ -88,6 +88,10 @@
             return Instructions.popVlan();
         } else if (subType.equals(L2ModificationInstruction.L2SubType.VLAN_PUSH.name())) {
             return Instructions.pushVlan();
+        } else if (subType.equals(L2ModificationInstruction.L2SubType.TUNNEL_ID.name())) {
+            long tunnelId = nullIsIllegal(json.get(InstructionCodec.TUNNEL_ID),
+                    InstructionCodec.TUNNEL_ID + InstructionCodec.MISSING_MEMBER_MESSAGE).asLong();
+            return Instructions.modTunnelId(tunnelId);
         }
         throw new IllegalArgumentException("L2 Instruction subtype "
                 + subType + " is not supported");