Improve the resiliency of the packet deserialization code.

Packet deserializers now check for malformed input while reading the byte
stream. Deserializers are re-implemented as functions that take a byte array
and return a packet object. The old IPacket.deserialize(...) methods have been
deprecated with the goal of eventually moving to immutable packet objects.
Unit tests have been implemented for all Deserializer functions.

ONOS-1589

Change-Id: I9073d5e6e7991e15d43830cfd810989256b71c56
diff --git a/utils/misc/src/main/java/org/onlab/packet/ipv6/Fragment.java b/utils/misc/src/main/java/org/onlab/packet/ipv6/Fragment.java
index 5a0d4b4..68015d3 100644
--- a/utils/misc/src/main/java/org/onlab/packet/ipv6/Fragment.java
+++ b/utils/misc/src/main/java/org/onlab/packet/ipv6/Fragment.java
@@ -18,11 +18,15 @@
 
 import org.onlab.packet.BasePacket;
 import org.onlab.packet.Data;
+import org.onlab.packet.DeserializationException;
+import org.onlab.packet.Deserializer;
 import org.onlab.packet.IPacket;
 import org.onlab.packet.IPv6;
 
 import java.nio.ByteBuffer;
 
+import static org.onlab.packet.PacketUtils.checkInput;
+
 /**
  * Implements IPv6 fragment extension header format. (RFC 2460)
  */
@@ -149,22 +153,19 @@
         this.moreFragment = (byte) (sscratch & 0x1);
         this.identification = bb.getInt();
 
-        IPacket payload;
-        if (IPv6.PROTOCOL_CLASS_MAP.containsKey(this.nextHeader)) {
-            final Class<? extends IPacket> clazz = IPv6.PROTOCOL_CLASS_MAP
-                    .get(this.nextHeader);
-            try {
-                payload = clazz.newInstance();
-            } catch (final Exception e) {
-                throw new RuntimeException(
-                        "Error parsing payload for Fragment packet", e);
-            }
+        Deserializer<? extends IPacket> deserializer;
+        if (IPv6.PROTOCOL_DESERIALIZER_MAP.containsKey(this.nextHeader)) {
+            deserializer = IPv6.PROTOCOL_DESERIALIZER_MAP.get(this.nextHeader);
         } else {
-            payload = new Data();
+            deserializer = Data.deserializer();
         }
-        this.payload = payload.deserialize(data, bb.position(),
-                bb.limit() - bb.position());
-        this.payload.setParent(this);
+        try {
+            this.payload = deserializer.deserialize(data, bb.position(),
+                                                    bb.limit() - bb.position());
+            this.payload.setParent(this);
+        } catch (DeserializationException e) {
+            return this;
+        }
 
         return this;
     }
@@ -216,4 +217,37 @@
         }
         return true;
     }
+
+    /**
+     * Deserializer function for fragment headers.
+     *
+     * @return deserializer function
+     */
+    public static Deserializer<Fragment> deserializer() {
+        return (data, offset, length) -> {
+            checkInput(data, offset, length, HEADER_LENGTH);
+
+            Fragment fragment = new Fragment();
+
+            ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
+            fragment.nextHeader = bb.get();
+            bb.get();
+            short sscratch = bb.getShort();
+            fragment.fragmentOffset = (short) (sscratch >> 3 & 0x1fff);
+            fragment.moreFragment = (byte) (sscratch & 0x1);
+            fragment.identification = bb.getInt();
+
+            Deserializer<? extends IPacket> deserializer;
+            if (IPv6.PROTOCOL_DESERIALIZER_MAP.containsKey(fragment.nextHeader)) {
+                deserializer = IPv6.PROTOCOL_DESERIALIZER_MAP.get(fragment.nextHeader);
+            } else {
+                deserializer = Data.deserializer();
+            }
+            fragment.payload = deserializer.deserialize(data, bb.position(),
+                                               bb.limit() - bb.position());
+            fragment.payload.setParent(fragment);
+
+            return fragment;
+        };
+    }
 }