[Emu][onos-2603] - Implement LinkState Link attributes-OSPF Forwarding Address

Change-Id: I6001acfb681512c97f048c324ae09e32fa340805

+/*
+ * Copyright 2015 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.bgpio.types.attr;
+
+import java.util.Objects;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.onlab.packet.Ip4Address;
+import org.onlab.packet.Ip6Address;
+import org.onosproject.bgpio.exceptions.BGPParseException;
+import org.onosproject.bgpio.types.BGPErrorType;
+import org.onosproject.bgpio.types.BGPValueType;
+import org.onosproject.bgpio.util.Validation;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.base.MoreObjects;
+
+/**
+ * Implements BGP prefix OSPF Forwarding address attribute.
+ */
+public class BgpPrefixAttrOspfFwdAddr implements BGPValueType {
+
+    protected static final Logger log = LoggerFactory
+            .getLogger(BgpPrefixAttrOspfFwdAddr.class);
+
+    public static final int ATTR_PREFIX_OSPFFWDADDR = 1156;
+    public static final int IPV4_LEN = 4;
+    public static final int IPV6_LEN = 16;
+
+    /* OSPF Forwarding Address */
+    private final short lsAttrLength;
+    private final Ip4Address ip4RouterId;
+    private final Ip6Address ip6RouterId;
+
+    /**
+     * Constructor to initialize the value.
+     *
+     * @param lsAttrLength length of the IP address
+     * @param ip4RouterId Valid IPV4 address if length is 4 else null
+     * @param ip6RouterId Valid IPV6 address if length is 16 else null
+     */
+    public BgpPrefixAttrOspfFwdAddr(short lsAttrLength, Ip4Address ip4RouterId,
+                                    Ip6Address ip6RouterId) {
+        this.lsAttrLength = lsAttrLength;
+        this.ip4RouterId = ip4RouterId;
+        this.ip6RouterId = ip6RouterId;
+    }
+
+    /**
+     * Returns object of this class with specified values.
+     *
+     * @param lsAttrLength length of the IP address
+     * @param ip4RouterId Valid IPV4 address if length is 4 else null
+     * @param ip6RouterId Valid IPV6 address if length is 16 else null
+     * @return object of BgpPrefixAttrOspfFwdAddr
+     */
+    public static BgpPrefixAttrOspfFwdAddr of(final short lsAttrLength,
+                                              final Ip4Address ip4RouterId,
+                                              final Ip6Address ip6RouterId) {
+        return new BgpPrefixAttrOspfFwdAddr(lsAttrLength, ip4RouterId,
+                                            ip6RouterId);
+    }
+
+    /**
+     * Reads the OSPF Forwarding Address.
+     *
+     * @param cb ChannelBuffer
+     * @return object of BgpPrefixAttrOSPFFwdAddr
+     * @throws BGPParseException while parsing BgpPrefixAttrOspfFwdAddr
+     */
+    public static BgpPrefixAttrOspfFwdAddr read(ChannelBuffer cb)
+            throws BGPParseException {
+        short lsAttrLength;
+        byte[] ipBytes;
+        Ip4Address ip4RouterId = null;
+        Ip6Address ip6RouterId = null;
+
+        lsAttrLength = cb.readShort();
+        ipBytes = new byte[lsAttrLength];
+
+        if ((cb.readableBytes() < lsAttrLength)) {
+            Validation.validateLen(BGPErrorType.UPDATE_MESSAGE_ERROR,
+                                   BGPErrorType.ATTRIBUTE_LENGTH_ERROR,
+                                   lsAttrLength);
+        }
+
+        cb.readBytes(ipBytes);
+
+        if (IPV4_LEN == lsAttrLength) {
+            ip4RouterId = Ip4Address.valueOf(ipBytes);
+        } else if (IPV6_LEN == lsAttrLength) {
+            ip6RouterId = Ip6Address.valueOf(ipBytes);
+        }
+
+        return BgpPrefixAttrOspfFwdAddr.of(lsAttrLength, ip4RouterId,
+                                           ip6RouterId);
+    }
+
+    /**
+     * Returns IPV4 Address of OSPF forwarding address.
+     *
+     * @return IPV4 address
+     */
+    public Ip4Address ospfv4FwdAddr() {
+        return ip4RouterId;
+    }
+
+    /**
+     * Returns IPV6 Address of OSPF forwarding address.
+     *
+     * @return IPV6 address
+     */
+    public Ip6Address ospfv6FwdAddr() {
+        return ip6RouterId;
+    }
+
+    /**
+     * Returns OSPF forwarding address length.
+     *
+     * @return length of the ip address
+     */
+    public short ospfFwdAddrLen() {
+        return lsAttrLength;
+    }
+
+    @Override
+    public short getType() {
+        return ATTR_PREFIX_OSPFFWDADDR;
+    }
+
+    @Override
+    public int hashCode() {
+        if (IPV4_LEN == lsAttrLength) {
+            return Objects.hash(ip4RouterId);
+        } else {
+            return Objects.hash(ip6RouterId);
+        }
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (obj instanceof BgpPrefixAttrOspfFwdAddr) {
+            BgpPrefixAttrOspfFwdAddr other = (BgpPrefixAttrOspfFwdAddr) obj;
+            if (IPV4_LEN == lsAttrLength) {
+                return Objects.equals(ip4RouterId, other.ip4RouterId);
+            } else {
+                return Objects.equals(ip6RouterId, other.ip6RouterId);
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public int write(ChannelBuffer cb) {
+        // TODO This will be implemented in the next version
+        return 0;
+    }
+
+    @Override
+    public String toString() {
+        if (IPV4_LEN == lsAttrLength) {
+            return MoreObjects.toStringHelper(getClass()).omitNullValues()
+                    .add("ip4RouterId", ip4RouterId).toString();
+        } else {
+            return MoreObjects.toStringHelper(getClass()).omitNullValues()
+                    .add("ip6RouterId", ip6RouterId).toString();
+        }
+    }
+}