ONOS-1993 Implement API-level permission checking + security util code location replacement

Change-Id: I7bf20eda9c12ed2a44334504333b093057764cd2
diff --git a/core/api/src/main/java/org/onosproject/net/packet/DefaultPacketContext.java b/core/api/src/main/java/org/onosproject/net/packet/DefaultPacketContext.java
index ffea2d8..b227b92 100644
--- a/core/api/src/main/java/org/onosproject/net/packet/DefaultPacketContext.java
+++ b/core/api/src/main/java/org/onosproject/net/packet/DefaultPacketContext.java
@@ -15,12 +15,16 @@
  */
 package org.onosproject.net.packet;
 
+import org.onosproject.core.Permission;
 import org.onosproject.net.flow.DefaultTrafficTreatment;
 import org.onosproject.net.flow.TrafficTreatment;
 import org.onosproject.net.flow.TrafficTreatment.Builder;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import static org.onosproject.security.AppGuard.checkPermission;
+
+
 /**
  * Default implementation of a packet context.
  */
@@ -53,21 +57,29 @@
 
     @Override
     public long time() {
+        checkPermission(Permission.PACKET_READ);
+
         return time;
     }
 
     @Override
     public InboundPacket inPacket() {
+        checkPermission(Permission.PACKET_READ);
+
         return inPkt;
     }
 
     @Override
     public OutboundPacket outPacket() {
+        checkPermission(Permission.PACKET_READ);
+
         return outPkt;
     }
 
     @Override
     public Builder treatmentBuilder() {
+        checkPermission(Permission.PACKET_READ);
+
         return builder;
     }
 
@@ -76,11 +88,15 @@
 
     @Override
     public boolean block() {
+        checkPermission(Permission.PACKET_WRITE);
+
         return this.block.getAndSet(true);
     }
 
     @Override
     public boolean isHandled() {
+        checkPermission(Permission.PACKET_READ);
+
         return this.block.get();
     }
-}
+}
\ No newline at end of file