ONOS-2739 - OSPF Basic Packet Structures , which includes encoding and decoding

Change-Id: Ic37fcf98dfb6c7a15a124b495aee8517a8df23c9
diff --git a/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/linksubtype/LinkType.java b/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/linksubtype/LinkType.java
new file mode 100644
index 0000000..8a13f83
--- /dev/null
+++ b/protocols/ospf/protocol/src/main/java/org/onosproject/ospf/protocol/lsa/linksubtype/LinkType.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.ospf.protocol.lsa.linksubtype;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.primitives.Bytes;
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.onosproject.ospf.exceptions.OspfErrorType;
+import org.onosproject.ospf.exceptions.OspfParseException;
+import org.onosproject.ospf.protocol.lsa.TlvHeader;
+import org.onosproject.ospf.protocol.util.OspfUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Representation of link type TE value.
+ */
+public class LinkType extends TlvHeader implements LinkSubType {
+    private static final Logger log =
+            LoggerFactory.getLogger(LinkType.class);
+    private int linkType;
+
+    /**
+     * Creates link type instance .
+     */
+    public LinkType() {
+
+    }
+
+    /**
+     * Creates link type instance.
+     *
+     * @param header tlv header instance
+     */
+    public LinkType(TlvHeader header) {
+        this.setTlvType(header.tlvType());
+        this.setTlvLength(header.tlvLength());
+    }
+
+    /**
+     * Sets link type.
+     *
+     * @param linkType value of link type
+     */
+    public void setLinkType(int linkType) {
+        this.linkType = linkType;
+    }
+
+    /**
+     * Reads from channel buffer.
+     *
+     * @param channelBuffer channel buffer instance
+     * @throws Exception might throws exception while parsing buffer
+     */
+    public void readFrom(ChannelBuffer channelBuffer) throws Exception {
+        try {
+            int len = channelBuffer.readableBytes();
+            byte[] tempByteArray = new byte[len];
+            channelBuffer.readBytes(tempByteArray, 0, len);
+            this.setLinkType(OspfUtil.byteToInteger(tempByteArray));
+        } catch (Exception e) {
+            log.debug("Error::LinkType:: {}", e.getMessage());
+            throw new OspfParseException(OspfErrorType.OSPF_MESSAGE_ERROR,
+                                         OspfErrorType.BAD_MESSAGE);
+        }
+    }
+
+    /**
+     * Gets link subtype as byte array.
+     *
+     * @return byte array of link subtype
+     */
+    public byte[] asBytes() {
+        byte[] linkSubType = null;
+
+        byte[] linkSubTlvHeader = getTlvHeaderAsByteArray();
+        byte[] linkSubTlvBody = getLinkSubTypeTlvBodyAsByteArray();
+        linkSubType = Bytes.concat(linkSubTlvHeader, linkSubTlvBody);
+        return linkSubType;
+    }
+
+    /**
+     * Gets link subtype as bytes.
+     *
+     * @return byte array of link subtype
+     */
+    public byte[] getLinkSubTypeTlvBodyAsByteArray() {
+        byte[] linkSubTypeBody = new byte[4];
+        linkSubTypeBody[0] = (byte) this.linkType;
+        linkSubTypeBody[1] = 0;
+        linkSubTypeBody[2] = 0;
+        linkSubTypeBody[3] = 0;
+        return linkSubTypeBody;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("linkType", linkType)
+                .toString();
+    }
+}
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