Support lambda's in selector & treatment
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instruction.java b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instruction.java
index 084ffe4..9b578b6 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instruction.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instruction.java
@@ -43,6 +43,11 @@
         GROUP,
 
         /**
+         * Signifies that the traffic should be modified in L0 way.
+         */
+        L0MODIFICATION,
+
+        /**
          * Signifies that the traffic should be modified in L2 way.
          */
         L2MODIFICATION,
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instructions.java b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instructions.java
index 988c52f..b18d7ef 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instructions.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/Instructions.java
@@ -24,6 +24,8 @@
 import java.util.Objects;
 
 import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.flow.instructions.L0ModificationInstruction.L0SubType;
+import org.onlab.onos.net.flow.instructions.L0ModificationInstruction.ModLambdaInstruction;
 import org.onlab.onos.net.flow.instructions.L2ModificationInstruction.L2SubType;
 import org.onlab.onos.net.flow.instructions.L2ModificationInstruction.ModEtherInstruction;
 import org.onlab.onos.net.flow.instructions.L3ModificationInstruction.L3SubType;
@@ -62,6 +64,16 @@
     }
 
     /**
+     * Creates a l0 modification.
+     * @param lambda the lambda to modify to.
+     * @return a l0 modification
+     */
+    public static L0ModificationInstruction modL0Lambda(short lambda) {
+        checkNotNull(lambda, "L0 lambda cannot be null");
+        return new ModLambdaInstruction(L0SubType.LAMBDA, lambda);
+    }
+
+    /**
      * Creates a l2 src modification.
      * @param addr the mac address to modify to.
      * @return a l2 modification
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L0ModificationInstruction.java b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L0ModificationInstruction.java
new file mode 100644
index 0000000..23e5f2a
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/instructions/L0ModificationInstruction.java
@@ -0,0 +1,75 @@
+package org.onlab.onos.net.flow.instructions;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+import java.util.Objects;
+
+public abstract class L0ModificationInstruction implements Instruction {
+
+    /**
+     * Represents the type of traffic treatment.
+     */
+    public enum L0SubType {
+        /**
+         * Lambda modification.
+         */
+        LAMBDA
+
+        //TODO: remaining types
+    }
+
+    public abstract L0SubType subtype();
+
+    @Override
+    public Type type() {
+        return Type.L0MODIFICATION;
+    }
+
+    /**
+     * Represents a L0 lambda modification instruction.
+     */
+    public static final class ModLambdaInstruction extends L0ModificationInstruction {
+
+        private final L0SubType subtype;
+        private final short lambda;
+
+        public ModLambdaInstruction(L0SubType subType, short lambda) {
+            this.subtype = subType;
+            this.lambda = lambda;
+        }
+
+        @Override
+        public L0SubType subtype() {
+            return this.subtype;
+        }
+
+        public short lambda() {
+            return this.lambda;
+        }
+
+        @Override
+        public String toString() {
+            return toStringHelper(subtype().toString())
+                    .add("lambda", lambda).toString();
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(lambda, type(), subtype);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (obj instanceof ModLambdaInstruction) {
+                ModLambdaInstruction that = (ModLambdaInstruction) obj;
+                return  Objects.equals(lambda, that.lambda) &&
+                        Objects.equals(this.type(), that.type()) &&
+                        Objects.equals(subtype, that.subtype);
+            }
+            return false;
+        }
+    }
+}