Ported BGP tests from old codebase

@@ -42,6 +42,16 @@
       <artifactId>onlab-thirdparty</artifactId>
     </dependency>
 
+    <dependency>
+      <groupId>org.onlab.onos</groupId>
+      <artifactId>onlab-misc</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>org.easymock</groupId>
+      <artifactId>easymock</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
 </project>

+package org.onlab.onos.sdnip.bgp;
+
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertThat;
+
+import java.util.ArrayList;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for the BgpRouteEntry.AsPath class.
+ */
+public class AsPathTest {
+    /**
+     * Generates an AS Path.
+     *
+     * @return a generated AS Path
+     */
+    private BgpRouteEntry.AsPath generateAsPath() {
+        ArrayList<BgpRouteEntry.PathSegment> pathSegments = new ArrayList<>();
+        byte pathSegmentType1 = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers1 = new ArrayList<>();
+        segmentAsNumbers1.add((long) 1);
+        segmentAsNumbers1.add((long) 2);
+        segmentAsNumbers1.add((long) 3);
+        BgpRouteEntry.PathSegment pathSegment1 =
+            new BgpRouteEntry.PathSegment(pathSegmentType1, segmentAsNumbers1);
+        pathSegments.add(pathSegment1);
+        //
+        byte pathSegmentType2 = (byte) BgpConstants.Update.AsPath.AS_SET;
+        ArrayList<Long> segmentAsNumbers2 = new ArrayList<>();
+        segmentAsNumbers2.add((long) 4);
+        segmentAsNumbers2.add((long) 5);
+        segmentAsNumbers2.add((long) 6);
+        BgpRouteEntry.PathSegment pathSegment2 =
+            new BgpRouteEntry.PathSegment(pathSegmentType2, segmentAsNumbers2);
+        pathSegments.add(pathSegment2);
+        //
+        BgpRouteEntry.AsPath asPath = new BgpRouteEntry.AsPath(pathSegments);
+
+        return asPath;
+    }
+
+    /**
+     * Tests valid class constructor.
+     */
+    @Test
+    public void testConstructor() {
+        BgpRouteEntry.AsPath asPath = generateAsPath();
+
+        String expectedString =
+            "AsPath{pathSegments=" +
+            "[PathSegment{type=2, segmentAsNumbers=[1, 2, 3]}, " +
+            "PathSegment{type=1, segmentAsNumbers=[4, 5, 6]}]}";
+        assertThat(asPath.toString(), is(expectedString));
+    }
+
+    /**
+     * Tests invalid class constructor for null Path Segments.
+     */
+    @Test(expected = NullPointerException.class)
+    public void testInvalidConstructorNullPathSegments() {
+        ArrayList<BgpRouteEntry.PathSegment> pathSegments = null;
+        new BgpRouteEntry.AsPath(pathSegments);
+    }
+
+    /**
+     * Tests getting the fields of an AS Path.
+     */
+    @Test
+    public void testGetFields() {
+        // Create the fields to compare against
+        ArrayList<BgpRouteEntry.PathSegment> pathSegments = new ArrayList<>();
+        byte pathSegmentType1 = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers1 = new ArrayList<>();
+        segmentAsNumbers1.add((long) 1);
+        segmentAsNumbers1.add((long) 2);
+        segmentAsNumbers1.add((long) 3);
+        BgpRouteEntry.PathSegment pathSegment1 =
+            new BgpRouteEntry.PathSegment(pathSegmentType1, segmentAsNumbers1);
+        pathSegments.add(pathSegment1);
+        //
+        byte pathSegmentType2 = (byte) BgpConstants.Update.AsPath.AS_SET;
+        ArrayList<Long> segmentAsNumbers2 = new ArrayList<>();
+        segmentAsNumbers2.add((long) 4);
+        segmentAsNumbers2.add((long) 5);
+        segmentAsNumbers2.add((long) 6);
+        BgpRouteEntry.PathSegment pathSegment2 =
+            new BgpRouteEntry.PathSegment(pathSegmentType2, segmentAsNumbers2);
+        pathSegments.add(pathSegment2);
+
+        // Generate the entry to test
+        BgpRouteEntry.AsPath asPath = generateAsPath();
+
+        assertThat(asPath.getPathSegments(), is(pathSegments));
+    }
+
+    /**
+     * Tests getting the AS Path Length.
+     */
+    @Test
+    public void testGetAsPathLength() {
+        BgpRouteEntry.AsPath asPath = generateAsPath();
+        assertThat(asPath.getAsPathLength(), is(4));
+
+        // Create an empty AS Path
+        ArrayList<BgpRouteEntry.PathSegment> pathSegments = new ArrayList<>();
+        asPath = new BgpRouteEntry.AsPath(pathSegments);
+        assertThat(asPath.getAsPathLength(), is(0));
+    }
+
+    /**
+     * Tests equality of {@link BgpRouteEntry.AsPath}.
+     */
+    @Test
+    public void testEquality() {
+        BgpRouteEntry.AsPath asPath1 = generateAsPath();
+        BgpRouteEntry.AsPath asPath2 = generateAsPath();
+
+        assertThat(asPath1, is(asPath2));
+    }
+
+    /**
+     * Tests non-equality of {@link BgpRouteEntry.AsPath}.
+     */
+    @Test
+    public void testNonEquality() {
+        BgpRouteEntry.AsPath asPath1 = generateAsPath();
+
+        // Setup AS Path 2
+        ArrayList<BgpRouteEntry.PathSegment> pathSegments = new ArrayList<>();
+        byte pathSegmentType1 = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers1 = new ArrayList<>();
+        segmentAsNumbers1.add((long) 1);
+        segmentAsNumbers1.add((long) 2);
+        segmentAsNumbers1.add((long) 3);
+        BgpRouteEntry.PathSegment pathSegment1 =
+            new BgpRouteEntry.PathSegment(pathSegmentType1, segmentAsNumbers1);
+        pathSegments.add(pathSegment1);
+        //
+        byte pathSegmentType2 = (byte) BgpConstants.Update.AsPath.AS_SET;
+        ArrayList<Long> segmentAsNumbers2 = new ArrayList<>();
+        segmentAsNumbers2.add((long) 4);
+        segmentAsNumbers2.add((long) 55);                       // Different
+        segmentAsNumbers2.add((long) 6);
+        BgpRouteEntry.PathSegment pathSegment2 =
+            new BgpRouteEntry.PathSegment(pathSegmentType2, segmentAsNumbers2);
+        pathSegments.add(pathSegment2);
+        //
+        BgpRouteEntry.AsPath asPath2 = new BgpRouteEntry.AsPath(pathSegments);
+
+        assertThat(asPath1, is(not(asPath2)));
+    }
+
+    /**
+     * Tests object string representation.
+     */
+    @Test
+    public void testToString() {
+        BgpRouteEntry.AsPath asPath = generateAsPath();
+
+        String expectedString =
+            "AsPath{pathSegments=" +
+            "[PathSegment{type=2, segmentAsNumbers=[1, 2, 3]}, " +
+            "PathSegment{type=1, segmentAsNumbers=[4, 5, 6]}]}";
+        assertThat(asPath.toString(), is(expectedString));
+    }
+}

+package org.onlab.onos.sdnip.bgp;
+
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.not;
+import static org.junit.Assert.assertThat;
+
+import java.util.ArrayList;
+
+import org.junit.Test;
+
+/**
+ * Unit tests for the BgpRouteEntry.PathSegment class.
+ */
+public class PathSegmentTest {
+    /**
+     * Generates a Path Segment.
+     *
+     * @return a generated PathSegment
+     */
+    private BgpRouteEntry.PathSegment generatePathSegment() {
+        byte pathSegmentType = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers = new ArrayList<>();
+        segmentAsNumbers.add((long) 1);
+        segmentAsNumbers.add((long) 2);
+        segmentAsNumbers.add((long) 3);
+        BgpRouteEntry.PathSegment pathSegment =
+            new BgpRouteEntry.PathSegment(pathSegmentType, segmentAsNumbers);
+
+        return pathSegment;
+    }
+
+    /**
+     * Tests valid class constructor.
+     */
+    @Test
+    public void testConstructor() {
+        BgpRouteEntry.PathSegment pathSegment = generatePathSegment();
+
+        String expectedString =
+            "PathSegment{type=2, segmentAsNumbers=[1, 2, 3]}";
+        assertThat(pathSegment.toString(), is(expectedString));
+    }
+
+    /**
+     * Tests invalid class constructor for null Segment AS Numbers.
+     */
+    @Test(expected = NullPointerException.class)
+    public void testInvalidConstructorNullSegmentAsNumbers() {
+        byte pathSegmentType = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers = null;
+        new BgpRouteEntry.PathSegment(pathSegmentType, segmentAsNumbers);
+    }
+
+    /**
+     * Tests getting the fields of a Path Segment.
+     */
+    @Test
+    public void testGetFields() {
+        // Create the fields to compare against
+        byte pathSegmentType = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers = new ArrayList<>();
+        segmentAsNumbers.add((long) 1);
+        segmentAsNumbers.add((long) 2);
+        segmentAsNumbers.add((long) 3);
+
+        // Generate the entry to test
+        BgpRouteEntry.PathSegment pathSegment = generatePathSegment();
+
+        assertThat(pathSegment.getType(), is(pathSegmentType));
+        assertThat(pathSegment.getSegmentAsNumbers(), is(segmentAsNumbers));
+    }
+
+    /**
+     * Tests equality of {@link BgpRouteEntry.PathSegment}.
+     */
+    @Test
+    public void testEquality() {
+        BgpRouteEntry.PathSegment pathSegment1 = generatePathSegment();
+        BgpRouteEntry.PathSegment pathSegment2 = generatePathSegment();
+
+        assertThat(pathSegment1, is(pathSegment2));
+    }
+
+    /**
+     * Tests non-equality of {@link BgpRouteEntry.PathSegment}.
+     */
+    @Test
+    public void testNonEquality() {
+        BgpRouteEntry.PathSegment pathSegment1 = generatePathSegment();
+
+        // Setup Path Segment 2
+        byte pathSegmentType = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        ArrayList<Long> segmentAsNumbers = new ArrayList<>();
+        segmentAsNumbers.add((long) 1);
+        segmentAsNumbers.add((long) 22);                        // Different
+        segmentAsNumbers.add((long) 3);
+        //
+        BgpRouteEntry.PathSegment pathSegment2 =
+            new BgpRouteEntry.PathSegment(pathSegmentType, segmentAsNumbers);
+
+        assertThat(pathSegment1, is(not(pathSegment2)));
+    }
+
+    /**
+     * Tests object string representation.
+     */
+    @Test
+    public void testToString() {
+        BgpRouteEntry.PathSegment pathSegment = generatePathSegment();
+
+        String expectedString =
+            "PathSegment{type=2, segmentAsNumbers=[1, 2, 3]}";
+        assertThat(pathSegment.toString(), is(expectedString));
+    }
+}

+package org.onlab.onos.sdnip.bgp;
+
+import java.util.Collection;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.ChannelStateEvent;
+import org.jboss.netty.channel.SimpleChannelHandler;
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.IpPrefix;
+
+/**
+ * Class for handling the remote BGP Peer session.
+ */
+class TestBgpPeerChannelHandler extends SimpleChannelHandler {
+    static final long PEER_AS = 65001;
+    static final int PEER_HOLDTIME = 120;       // 120 seconds
+    final IpAddress bgpId;                     // The BGP ID
+    final long localPref;                       // Local preference for routes
+    final long multiExitDisc = 20;              // MED value
+
+    ChannelHandlerContext savedCtx;
+
+    /**
+     * Constructor for given BGP ID.
+     *
+     * @param bgpId the BGP ID to use
+     * @param localPref the local preference for the routes to use
+     */
+    TestBgpPeerChannelHandler(IpAddress bgpId,
+                              long localPref) {
+        this.bgpId = bgpId;
+        this.localPref = localPref;
+    }
+
+    /**
+     * Closes the channel.
+     */
+    void closeChannel() {
+        savedCtx.getChannel().close();
+    }
+
+    @Override
+    public void channelConnected(ChannelHandlerContext ctx,
+                                 ChannelStateEvent channelEvent) {
+        this.savedCtx = ctx;
+        // Prepare and transmit BGP OPEN message
+        ChannelBuffer message = prepareBgpOpen();
+        ctx.getChannel().write(message);
+
+        // Prepare and transmit BGP KEEPALIVE message
+        message = prepareBgpKeepalive();
+        ctx.getChannel().write(message);
+    }
+
+    @Override
+    public void channelDisconnected(ChannelHandlerContext ctx,
+                                    ChannelStateEvent channelEvent) {
+        // Nothing to do
+    }
+
+    /**
+     * Prepares BGP OPEN message.
+     *
+     * @return the message to transmit (BGP header included)
+     */
+    ChannelBuffer prepareBgpOpen() {
+        ChannelBuffer message =
+            ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
+        message.writeByte(BgpConstants.BGP_VERSION);
+        message.writeShort((int) PEER_AS);
+        message.writeShort(PEER_HOLDTIME);
+        message.writeInt(bgpId.toInt());
+        message.writeByte(0);                   // No Optional Parameters
+        return prepareBgpMessage(BgpConstants.BGP_TYPE_OPEN, message);
+    }
+
+    /**
+     * Prepares BGP UPDATE message.
+     *
+     * @param nextHopRouter the next-hop router address for the routes to add
+     * @param addedRoutes the routes to add
+     * @param withdrawnRoutes the routes to withdraw
+     * @return the message to transmit (BGP header included)
+     */
+    ChannelBuffer prepareBgpUpdate(IpAddress nextHopRouter,
+                                   Collection<IpPrefix> addedRoutes,
+                                   Collection<IpPrefix> withdrawnRoutes) {
+        int attrFlags;
+        ChannelBuffer message =
+            ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
+        ChannelBuffer pathAttributes =
+            ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
+
+        // Encode the Withdrawn Routes
+        ChannelBuffer encodedPrefixes = encodePackedPrefixes(withdrawnRoutes);
+        message.writeShort(encodedPrefixes.readableBytes());
+        message.writeBytes(encodedPrefixes);
+
+        // Encode the Path Attributes
+        // ORIGIN: IGP
+        attrFlags = 0x40;                               // Transitive flag
+        pathAttributes.writeByte(attrFlags);
+        pathAttributes.writeByte(BgpConstants.Update.Origin.TYPE);
+        pathAttributes.writeByte(1);                    // Data length
+        pathAttributes.writeByte(BgpConstants.Update.Origin.IGP);
+        // AS_PATH: Two Path Segments of 3 ASes each
+        attrFlags = 0x40;                               // Transitive flag
+        pathAttributes.writeByte(attrFlags);
+        pathAttributes.writeByte(BgpConstants.Update.AsPath.TYPE);
+        pathAttributes.writeByte(16);                   // Data length
+        byte pathSegmentType1 = (byte) BgpConstants.Update.AsPath.AS_SEQUENCE;
+        pathAttributes.writeByte(pathSegmentType1);
+        pathAttributes.writeByte(3);                    // Three ASes
+        pathAttributes.writeShort(65010);               // AS=65010
+        pathAttributes.writeShort(65020);               // AS=65020
+        pathAttributes.writeShort(65030);               // AS=65030
+        byte pathSegmentType2 = (byte) BgpConstants.Update.AsPath.AS_SET;
+        pathAttributes.writeByte(pathSegmentType2);
+        pathAttributes.writeByte(3);                    // Three ASes
+        pathAttributes.writeShort(65041);               // AS=65041
+        pathAttributes.writeShort(65042);               // AS=65042
+        pathAttributes.writeShort(65043);               // AS=65043
+        // NEXT_HOP: nextHopRouter
+        attrFlags = 0x40;                               // Transitive flag
+        pathAttributes.writeByte(attrFlags);
+        pathAttributes.writeByte(BgpConstants.Update.NextHop.TYPE);
+        pathAttributes.writeByte(4);                    // Data length
+        pathAttributes.writeInt(nextHopRouter.toInt()); // Next-hop router
+        // LOCAL_PREF: localPref
+        attrFlags = 0x40;                               // Transitive flag
+        pathAttributes.writeByte(attrFlags);
+        pathAttributes.writeByte(BgpConstants.Update.LocalPref.TYPE);
+        pathAttributes.writeByte(4);                    // Data length
+        pathAttributes.writeInt((int) localPref);       // Preference value
+        // MULTI_EXIT_DISC: multiExitDisc
+        attrFlags = 0x80;                               // Optional
+                                                        // Non-Transitive flag
+        pathAttributes.writeByte(attrFlags);
+        pathAttributes.writeByte(BgpConstants.Update.MultiExitDisc.TYPE);
+        pathAttributes.writeByte(4);                    // Data length
+        pathAttributes.writeInt((int) multiExitDisc);   // Preference value
+        // The NLRI prefixes
+        encodedPrefixes = encodePackedPrefixes(addedRoutes);
+
+        // Write the Path Attributes, beginning with its length
+        message.writeShort(pathAttributes.readableBytes());
+        message.writeBytes(pathAttributes);
+        message.writeBytes(encodedPrefixes);
+
+        return prepareBgpMessage(BgpConstants.BGP_TYPE_UPDATE, message);
+    }
+
+    /**
+     * Encodes a collection of IPv4 network prefixes in a packed format.
+     * <p>
+     * The IPv4 prefixes are encoded in the form:
+     * <Length, Prefix> where Length is the length in bits of the IPv4 prefix,
+     * and Prefix is the IPv4 prefix (padded with trailing bits to the end
+     * of an octet).
+     *
+     * @param prefixes the prefixes to encode
+     * @return the buffer with the encoded prefixes
+     */
+    private ChannelBuffer encodePackedPrefixes(Collection<IpPrefix> prefixes) {
+        ChannelBuffer message =
+            ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
+
+        // Write each of the prefixes
+        for (IpPrefix prefix : prefixes) {
+            int prefixBitlen = prefix.prefixLength();
+            int prefixBytelen = (prefixBitlen + 7) / 8;         // Round-up
+            message.writeByte(prefixBitlen);
+
+            IpAddress address = prefix.toIpAddress();
+            long value = address.toInt() & 0xffffffffL;
+            for (int i = 0; i < IpAddress.INET_LEN; i++) {
+                if (prefixBytelen-- == 0) {
+                    break;
+                }
+                long nextByte =
+                    (value >> ((IpAddress.INET_LEN - i - 1) * 8)) & 0xff;
+                message.writeByte((int) nextByte);
+            }
+        }
+
+        return message;
+    }
+
+    /**
+     * Prepares BGP KEEPALIVE message.
+     *
+     * @return the message to transmit (BGP header included)
+     */
+    ChannelBuffer prepareBgpKeepalive() {
+        ChannelBuffer message =
+            ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
+        return prepareBgpMessage(BgpConstants.BGP_TYPE_KEEPALIVE, message);
+    }
+
+    /**
+     * Prepares BGP NOTIFICATION message.
+     *
+     * @param errorCode the BGP NOTIFICATION Error Code
+     * @param errorSubcode the BGP NOTIFICATION Error Subcode if applicable,
+     * otherwise BgpConstants.Notifications.ERROR_SUBCODE_UNSPECIFIC
+     * @param payload the BGP NOTIFICATION Data if applicable, otherwise null
+     * @return the message to transmit (BGP header included)
+     */
+    ChannelBuffer prepareBgpNotification(int errorCode, int errorSubcode,
+                                         ChannelBuffer data) {
+        ChannelBuffer message =
+            ChannelBuffers.buffer(BgpConstants.BGP_MESSAGE_MAX_LENGTH);
+        // Prepare the NOTIFICATION message payload
+        message.writeByte(errorCode);
+        message.writeByte(errorSubcode);
+        if (data != null) {
+            message.writeBytes(data);
+        }
+        return prepareBgpMessage(BgpConstants.BGP_TYPE_NOTIFICATION, message);
+    }
+
+    /**
+     * Prepares BGP message.
+     *
+     * @param type the BGP message type
+     * @param payload the message payload to transmit (BGP header excluded)
+     * @return the message to transmit (BGP header included)
+     */
+    private ChannelBuffer prepareBgpMessage(int type, ChannelBuffer payload) {
+        ChannelBuffer message =
+            ChannelBuffers.buffer(BgpConstants.BGP_HEADER_LENGTH +
+                                  payload.readableBytes());
+
+        // Write the marker
+        for (int i = 0; i < BgpConstants.BGP_HEADER_MARKER_LENGTH; i++) {
+            message.writeByte(0xff);
+        }
+
+        // Write the rest of the BGP header
+        message.writeShort(BgpConstants.BGP_HEADER_LENGTH +
+                           payload.readableBytes());
+        message.writeByte(type);
+
+        // Write the payload
+        message.writeBytes(payload);
+        return message;
+    }
+}

+package org.onlab.onos.sdnip.bgp;
+
+import java.util.concurrent.CountDownLatch;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.handler.codec.frame.FrameDecoder;
+import org.onlab.packet.IpAddress;
+
+/**
+ * Class for handling the decoding of the BGP messages at the remote
+ * BGP peer session.
+ */
+class TestBgpPeerFrameDecoder extends FrameDecoder {
+    int remoteBgpVersion;               // 1 octet
+    long remoteAs;                      // 2 octets
+    long remoteHoldtime;                // 2 octets
+    IpAddress remoteBgpIdentifier;     // 4 octets -> IPv4 address
+
+    final CountDownLatch receivedOpenMessageLatch = new CountDownLatch(1);
+    final CountDownLatch receivedKeepaliveMessageLatch = new CountDownLatch(1);
+
+    @Override
+    protected Object decode(ChannelHandlerContext ctx,
+                            Channel channel,
+                            ChannelBuffer buf) throws Exception {
+        // Test for minimum length of the BGP message
+        if (buf.readableBytes() < BgpConstants.BGP_HEADER_LENGTH) {
+            // No enough data received
+            return null;
+        }
+
+        //
+        // Mark the current buffer position in case we haven't received
+        // the whole message.
+        //
+        buf.markReaderIndex();
+
+        //
+        // Read and check the BGP message Marker field: it must be all ones
+        //
+        byte[] marker = new byte[BgpConstants.BGP_HEADER_MARKER_LENGTH];
+        buf.readBytes(marker);
+        for (int i = 0; i < marker.length; i++) {
+            if (marker[i] != (byte) 0xff) {
+                // ERROR: Connection Not Synchronized. Close the channel.
+                ctx.getChannel().close();
+                return null;
+            }
+        }
+
+        //
+        // Read and check the BGP message Length field
+        //
+        int length = buf.readUnsignedShort();
+        if ((length < BgpConstants.BGP_HEADER_LENGTH) ||
+            (length > BgpConstants.BGP_MESSAGE_MAX_LENGTH)) {
+            // ERROR: Bad Message Length. Close the channel.
+            ctx.getChannel().close();
+            return null;
+        }
+
+        //
+        // Test whether the rest of the message is received:
+        // So far we have read the Marker (16 octets) and the
+        // Length (2 octets) fields.
+        //
+        int remainingMessageLen =
+            length - BgpConstants.BGP_HEADER_MARKER_LENGTH - 2;
+        if (buf.readableBytes() < remainingMessageLen) {
+            // No enough data received
+            buf.resetReaderIndex();
+            return null;
+        }
+
+        //
+        // Read the BGP message Type field, and process based on that type
+        //
+        int type = buf.readUnsignedByte();
+        remainingMessageLen--;      // Adjust after reading the type
+        ChannelBuffer message = buf.readBytes(remainingMessageLen);
+
+        //
+        // Process the remaining of the message based on the message type
+        //
+        switch (type) {
+        case BgpConstants.BGP_TYPE_OPEN:
+            processBgpOpen(ctx, message);
+            break;
+        case BgpConstants.BGP_TYPE_UPDATE:
+            // NOTE: Not used as part of the test, because ONOS does not
+            // originate UPDATE messages.
+            break;
+        case BgpConstants.BGP_TYPE_NOTIFICATION:
+            // NOTE: Not used as part of the testing (yet)
+            break;
+        case BgpConstants.BGP_TYPE_KEEPALIVE:
+            processBgpKeepalive(ctx, message);
+            break;
+        default:
+            // ERROR: Bad Message Type. Close the channel.
+            ctx.getChannel().close();
+            return null;
+        }
+
+        return null;
+    }
+
+    /**
+     * Processes BGP OPEN message.
+     *
+     * @param ctx the Channel Handler Context.
+     * @param message the message to process.
+     */
+    private void processBgpOpen(ChannelHandlerContext ctx,
+                                ChannelBuffer message) {
+        int minLength =
+            BgpConstants.BGP_OPEN_MIN_LENGTH - BgpConstants.BGP_HEADER_LENGTH;
+        if (message.readableBytes() < minLength) {
+            // ERROR: Bad Message Length. Close the channel.
+            ctx.getChannel().close();
+            return;
+        }
+
+        //
+        // Parse the OPEN message
+        //
+        remoteBgpVersion = message.readUnsignedByte();
+        remoteAs = message.readUnsignedShort();
+        remoteHoldtime = message.readUnsignedShort();
+        remoteBgpIdentifier = IpAddress.valueOf((int) message.readUnsignedInt());
+        // Optional Parameters
+        int optParamLen = message.readUnsignedByte();
+        if (message.readableBytes() < optParamLen) {
+            // ERROR: Bad Message Length. Close the channel.
+            ctx.getChannel().close();
+            return;
+        }
+        message.readBytes(optParamLen);             // NOTE: data ignored
+
+        // BGP OPEN message successfully received
+        receivedOpenMessageLatch.countDown();
+    }
+
+    /**
+     * Processes BGP KEEPALIVE message.
+     *
+     * @param ctx the Channel Handler Context.
+     * @param message the message to process.
+     */
+    private void processBgpKeepalive(ChannelHandlerContext ctx,
+                                     ChannelBuffer message) {
+        if (message.readableBytes() + BgpConstants.BGP_HEADER_LENGTH !=
+            BgpConstants.BGP_KEEPALIVE_EXPECTED_LENGTH) {
+            // ERROR: Bad Message Length. Close the channel.
+            ctx.getChannel().close();
+            return;
+        }
+        // BGP KEEPALIVE message successfully received
+        receivedKeepaliveMessageLatch.countDown();
+    }
+}

+package org.onlab.util;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+
+/**
+ * Utilities for testing.
+ */
+public final class TestUtils {
+
+    /**
+     * Sets the field, bypassing scope restriction.
+     *
+     * @param subject Object where the field belongs
+     * @param fieldName name of the field to set
+     * @param value value to set to the field.
+     * @param <T> subject type
+     * @param <U> value type
+     * @throws TestUtilsException if there are reflection errors while setting
+     * the field
+     */
+    public static <T, U> void setField(T subject, String fieldName, U value)
+            throws TestUtilsException {
+        @SuppressWarnings("unchecked")
+        Class<T> clazz = (Class<T>) subject.getClass();
+        try {
+            Field field = clazz.getDeclaredField(fieldName);
+            field.setAccessible(true);
+            field.set(subject, value);
+        } catch (NoSuchFieldException | SecurityException |
+                 IllegalArgumentException | IllegalAccessException e) {
+            throw new TestUtilsException("setField failed", e);
+        }
+    }
+
+    /**
+     * Gets the field, bypassing scope restriction.
+     *
+     * @param subject Object where the field belongs
+     * @param fieldName name of the field to get
+     * @return value of the field.
+     * @param <T> subject type
+     * @param <U> field value type
+     * @throws TestUtilsException if there are reflection errors while getting
+     * the field
+     */
+    public static <T, U> U getField(T subject, String fieldName)
+            throws TestUtilsException {
+        try {
+            @SuppressWarnings("unchecked")
+            Class<T> clazz = (Class<T>) subject.getClass();
+            Field field = clazz.getDeclaredField(fieldName);
+            field.setAccessible(true);
+
+            @SuppressWarnings("unchecked")
+            U result = (U) field.get(subject);
+            return result;
+        } catch (NoSuchFieldException | SecurityException |
+                 IllegalArgumentException | IllegalAccessException e) {
+            throw new TestUtilsException("getField failed", e);
+        }
+    }
+
+    /**
+     * Calls the method, bypassing scope restriction.
+     *
+     * @param subject Object where the method belongs
+     * @param methodName name of the method to call
+     * @param paramTypes formal parameter type array
+     * @param args arguments
+     * @return return value or null if void
+     * @param <T> subject type
+     * @param <U> return value type
+     * @throws TestUtilsException if there are reflection errors while calling
+     * the method
+     */
+    public static <T, U> U callMethod(T subject, String methodName,
+            Class<?>[] paramTypes, Object...args) throws TestUtilsException {
+
+        try {
+            @SuppressWarnings("unchecked")
+            Class<T> clazz = (Class<T>) subject.getClass();
+            final Method method;
+            if (paramTypes == null || paramTypes.length == 0) {
+                method = clazz.getDeclaredMethod(methodName);
+            } else {
+                method = clazz.getDeclaredMethod(methodName, paramTypes);
+            }
+            method.setAccessible(true);
+
+            @SuppressWarnings("unchecked")
+            U result = (U) method.invoke(subject, args);
+            return result;
+        } catch (NoSuchMethodException | SecurityException |
+                IllegalAccessException | IllegalArgumentException |
+                InvocationTargetException e) {
+            throw new TestUtilsException("callMethod failed", e);
+        }
+    }
+
+    /**
+     * Calls the method, bypassing scope restriction.
+     *
+     * @param subject Object where the method belongs
+     * @param methodName name of the method to call
+     * @param paramType formal parameter type
+     * @param arg argument
+     * @return return value or null if void
+     * @param <T> subject type
+     * @param <U> return value type
+     * @throws TestUtilsException if there are reflection errors while calling
+     * the method
+     */
+    public static <T, U> U callMethod(T subject, String methodName,
+            Class<?> paramType, Object arg) throws TestUtilsException {
+        return callMethod(subject, methodName, new Class<?>[]{paramType}, arg);
+    }
+
+    /**
+     * Triggers an allocation of an object of type <T> and forces a call to
+     * the private constructor.
+     *
+     * @param constructor Constructor to call
+     * @param <T> type of the object to create
+     * @return created object of type <T>
+     * @throws TestUtilsException if there are reflection errors while calling
+     * the constructor
+     */
+    public static <T> T callConstructor(Constructor<T> constructor)
+            throws TestUtilsException {
+        try {
+            constructor.setAccessible(true);
+            return constructor.newInstance();
+        } catch (InstantiationException | IllegalAccessException |
+                InvocationTargetException error) {
+            throw new TestUtilsException("callConstructor failed", error);
+        }
+    }
+
+    /**
+     * Avoid instantiation.
+     */
+    private TestUtils() {}
+
+    /**
+     * Exception that can be thrown if problems are encountered while executing
+     * the utility method. These are usually problems accessing fields/methods
+     * through reflection. The original exception can be found by examining the
+     * cause.
+     */
+    public static class TestUtilsException extends Exception {
+
+        private static final long serialVersionUID = 1L;
+
+        /**
+         * Constructs a new exception with the specified detail message and
+         * cause.
+         *
+         * @param message the detail message
+         * @param cause the original cause of this exception
+         */
+        public TestUtilsException(String message, Throwable cause) {
+            super(message, cause);
+        }
+    }
+}

+package org.onlab.util;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.util.TestUtils.TestUtilsException;
+
+/**
+ * Test and usage examples for TestUtils.
+ */
+public class TestUtilsTest {
+
+    /**
+     * Test data.
+     */
+    private static final class TestClass {
+
+        @SuppressWarnings("unused")
+        private int privateField = 42;
+
+        @SuppressWarnings("unused")
+        protected int protectedField = 2501; // CHECKSTYLE IGNORE THIS LINE
+
+        /**
+         * Protected method with multiple argument.
+         *
+         * @param x simply returns
+         * @param y not used
+         * @return x
+         */
+        @SuppressWarnings("unused")
+        private int privateMethod(Number x, Long y) {
+            return x.intValue();
+        }
+
+        /**
+         * Protected method with no argument.
+         *
+         * @return int
+         */
+        @SuppressWarnings("unused")
+        protected int protectedMethod() {
+            return 42;
+        }
+
+        /**
+         * Method returning array.
+         *
+         * @param ary random array
+         * @return ary
+         */
+        @SuppressWarnings("unused")
+        private int[] arrayReturnMethod(int[] ary) {
+            return ary;
+        }
+
+        /**
+         * Method without return value.
+         *
+         * @param s ignored
+         */
+        @SuppressWarnings("unused")
+        private void voidMethod(String s) {
+            System.out.println(s);
+        }
+    }
+
+    private TestClass test;
+
+    /**
+     * Sets up the test fixture.
+     */
+    @Before
+    public void setUp() {
+        test = new TestClass();
+    }
+
+    /**
+     * Example to access private field.
+     *
+     * @throws TestUtilsException TestUtils error
+     */
+    @Test
+    public void testSetGetPrivateField() throws TestUtilsException {
+
+        assertEquals(42, TestUtils.getField(test, "privateField"));
+        TestUtils.setField(test, "privateField", 0xDEAD);
+        assertEquals(0xDEAD, TestUtils.getField(test, "privateField"));
+    }
+
+    /**
+     * Example to access protected field.
+     *
+     * @throws TestUtilsException TestUtils error
+     */
+    @Test
+    public void testSetGetProtectedField() throws TestUtilsException {
+
+        assertEquals(2501, TestUtils.getField(test, "protectedField"));
+        TestUtils.setField(test, "protectedField", 0xBEEF);
+        assertEquals(0xBEEF, TestUtils.getField(test, "protectedField"));
+    }
+
+    /**
+     * Example to call private method and multiple parameters.
+     * <p/>
+     * It also illustrates that paramTypes must match declared type,
+     * not the runtime types of arguments.
+     *
+     * @throws TestUtilsException TestUtils error
+     */
+    @Test
+    public void testCallPrivateMethod() throws TestUtilsException {
+
+        int result = TestUtils.callMethod(test, "privateMethod",
+                        new Class<?>[] {Number.class, Long.class},
+                        Long.valueOf(42), Long.valueOf(32));
+        assertEquals(42, result);
+    }
+
+    /**
+     * Example to call protected method and no parameters.
+     *
+     * @throws TestUtilsException TestUtils error
+     */
+    @Test
+    public void testCallProtectedMethod() throws TestUtilsException {
+
+        int result = TestUtils.callMethod(test, "protectedMethod",
+                        new Class<?>[] {});
+        assertEquals(42, result);
+    }
+
+    /**
+     * Example to call method returning array.
+     * <p/>
+     * Note: It is not required to receive as Object.
+     * Following is just verifying it is not Boxed arrays.
+     *
+     * @throws TestUtilsException TestUtils error
+     */
+    @Test
+    public void testCallArrayReturnMethod() throws TestUtilsException {
+
+        int[] array = {1, 2, 3};
+        Object aryResult = TestUtils.callMethod(test, "arrayReturnMethod",
+                new Class<?>[] {int[].class}, array);
+        assertEquals(int[].class, aryResult.getClass());
+        assertArrayEquals(array, (int[]) aryResult);
+    }
+
+
+    /**
+     * Example to call void returning method.
+     * <p/>
+     * Note: Return value will be null for void methods.
+     *
+     * @throws TestUtilsException TestUtils error
+     */
+    @Test
+    public void testCallVoidReturnMethod() throws TestUtilsException {
+
+        Object voidResult = TestUtils.callMethod(test, "voidMethod",
+                String.class, "foobar");
+        assertNull(voidResult);
+    }
+}