Getting router interface config into the corsa dataplane pipeline

Change-Id: I67d5bf7a20190b07a7bf55c7b60f771877ca8dbb
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
index 926d267..e0a5ca6 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
@@ -255,6 +255,19 @@
         return new PushHeaderInstructions(L2SubType.MPLS_POP, etherType);
     }
 
+    /**
+     * Creates a vlan header instruction.
+     * @return a L2 modification.
+     */
+    public static Instruction popVlan() {
+        return new PopVlanInstruction(L2SubType.VLAN_POP);
+    }
+
+    /**
+     * Sends the packet to the table described in 'type'.
+     * @param type
+     * @return
+     */
     public static Instruction transition(FlowRule.Type type) {
         checkNotNull(type, "Table type cannot be null");
         return new TableTypeTransition(type);