src/main/java/com/intel/jndn/management/NFD.java

/*
 * File name: NFD.java
 * 
 * Purpose: Helper class for interacting with an NDN forwarder daemon;
 * see http://redmine.named-data.net/projects/nfd/wiki/Management for 
 * explanations of the various protocols used.
 * 
 * © Copyright Intel Corporation. All rights reserved.
 * Intel Corporation, 2200 Mission College Boulevard,
 * Santa Clara, CA 95052-8119, USA
 */
package com.intel.jndn.management;

import com.intel.jndn.utils.Client;
import java.io.IOException;
import java.util.List;
import net.named_data.jndn.ControlParameters;
import net.named_data.jndn.Data;
import net.named_data.jndn.Face;
import net.named_data.jndn.ForwardingFlags;
import net.named_data.jndn.Interest;
import net.named_data.jndn.Name;
import net.named_data.jndn.encoding.EncodingException;
import net.named_data.jndn.security.SecurityException;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/**
 * Helper class for interacting with an NDN forwarder daemon; see
 * http://redmine.named-data.net/projects/nfd/wiki/Management for explanations
 * of the various protocols used.
 *
 * @author Andrew Brown <andrew.brown@intel.com>
 */
public class NFD {

	public final static long DEFAULT_TIMEOUT = 2000;
	private static final Logger logger = LogManager.getLogger();

	/**
	 * Ping a forwarder on an existing face to verify that the forwarder is
	 * working and responding to requests; this version sends a discovery packet
	 * to /localhost/nfd which should always respond if the requestor is on the
	 * same machine as the NDN forwarding daemon.
	 *
	 * @param face 
	 * @return true if successful, false otherwise
	 */
	public static boolean pingLocal(Face face) {
		return ping(face, new Name("/localhost/nfd"));
	}

	/**
	 * Request a name on an existing face to verify the forwarder is working and
	 * responding to requests. Note that the name must be served or cached on
	 * the forwarder for this to return true.
	 *
	 * @param face
	 * @param name
	 * @return true if successful, false otherwise
	 */
	public static boolean ping(Face face, Name name) {
		// build interest
		Interest interest = new Interest(name);
		interest.setInterestLifetimeMilliseconds(DEFAULT_TIMEOUT);
		interest.setMustBeFresh(true);

		// send packet
		Data data = Client.getDefault().getSync(face, interest);
		return data != null;
	}

	/**
	 * Retrieve a list of faces and their status from the given forwarder; calls
	 * /localhost/nfd/faces/list which requires a local Face (all non-local
	 * packets are dropped)
	 *
	 * @param forwarder Only a localhost Face
	 * @return
	 * @throws Exception
	 */
	public static List<FaceStatus> getFaceList(Face forwarder) throws Exception {
		// build management Interest packet; see http://redmine.named-data.net/projects/nfd/wiki/StatusDataset
		Interest interest = new Interest(new Name("/localhost/nfd/faces/list"));
		interest.setMustBeFresh(true);
		interest.setChildSelector(Interest.CHILD_SELECTOR_RIGHT);
		interest.setInterestLifetimeMilliseconds(DEFAULT_TIMEOUT);

		// TODO verify that all faces are being returned; right now they don't
		// match up with the results from nfd-status-http-server but no 
		// additional segments are present;  
		// see http://redmine.named-data.net/projects/nfd/wiki/StatusDataset
		// send packet
		Data data = Client.getDefault().getSync(forwarder, interest);
		if (data == null) {
			throw new Exception("Failed to retrieve list of faces from the forwarder.");
		}

		// parse packet
		return FaceStatus.decode(data);
	}

	/**
	 * Helper method to register a new face on the forwarder; as mentioned at
	 * http://named-data.net/doc/NFD/current/manpages/nfdc.html, this is more
	 * for debugging; use 'register' instead
	 *
	 * @param forwarder Only a localhost Face
	 * @param faceId
	 * @param prefix
	 * @return
	 * @throws Exception
	 */
	public static boolean addNextHop(Face forwarder, int faceId, Name prefix) throws Exception {
		// build command name
		Name command = new Name("/localhost/nfd/fib/add-nexthop");
		ControlParameters parameters = new ControlParameters();
		parameters.setName(prefix);
		parameters.setFaceId(faceId);
		command.append(parameters.wireEncode());

		// send the interest
		return sendCommandAndErrorCheck(forwarder, new Interest(command));
	}

	/**
	 * Create a new face on the given forwarder. Ensure the forwarding face is
	 * on the local machine (management requests are to /localhost/...) and that
	 * command signing has been set up (e.g. forwarder.setCommandSigningInfo()).
	 *
	 * @param forwarder Only a localhost Face
	 * @param uri
	 * @return
	 * @throws java.lang.Exception
	 */
	public static int createFace(Face forwarder, String uri) throws Exception {
		Name command = new Name("/localhost/nfd/faces/create");
		ControlParameters parameters = new ControlParameters();
		parameters.setUri(uri);
		command.append(parameters.wireEncode());

		// send the interest
		ControlResponse response = sendCommand(forwarder, new Interest(command));

		// check for body
		if (response.Body.isEmpty()) {
			throw new Exception("Failed to create face: " + uri);
		}

		// return
		return response.Body.get(0).getFaceId();
	}

	/**
	 * Register a route on the forwarder; see
	 * http://named-data.net/doc/NFD/current/manpages/nfdc.html for command-line
	 * usage and http://redmine.named-data.net/projects/nfd/wiki/RibMgmt for
	 * protocol documentation. Ensure the forwarding face is on the local
	 * machine (management requests are to /localhost/...) and that command
	 * signing has been set up (e.g. forwarder.setCommandSigningInfo()).
	 *
	 * @param forwarder Only a localhost Face
	 * @param controlParameters
	 * @return
	 * @throws Exception
	 */
	public static boolean register(Face forwarder, ControlParameters controlParameters) throws Exception {
		// build command name
		Name command = new Name("/localhost/nfd/rib/register");
		command.append(controlParameters.wireEncode());

		// send the interest
		return sendCommandAndErrorCheck(forwarder, new Interest(command));
	}

	/**
	 * Register a route on a forwarder; this will create a new face on the
	 * forwarder to the given URI/route pair. See register(Face,
	 * ControlParameters) for more details documentation.
	 *
	 * @param forwarder Only a localhost Face
	 * @param uri
	 * @param cost
	 * @param route
	 * @return true for successful registration
	 * @throws java.lang.Exception
	 */
	public static boolean register(Face forwarder, String uri, Name route, int cost) throws Exception {
		// create the new face
		int faceId = createFace(forwarder, uri);

		// run base method
		return register(forwarder, faceId, route, cost);
	}

	/**
	 * Register a route on a forwarder; this will not create a new face since it
	 * is provided a faceId. See register(Face, ControlParameters) for full
	 * documentation
	 *
	 * @param forwarder Only a localhost Face
	 * @param faceId
	 * @param route
	 * @param cost
	 * @return true for successful registration
	 * @throws java.lang.Exception
	 */
	public static boolean register(Face forwarder, int faceId, Name route, int cost) throws Exception {
		// build command name
		ControlParameters parameters = new ControlParameters();
		parameters.setName(route);
		parameters.setFaceId(faceId);
		parameters.setCost(cost);
		ForwardingFlags flags = new ForwardingFlags();
		flags.setCapture(true);
		flags.setChildInherit(true);
		parameters.setForwardingFlags(flags);

		// run base method
		return register(forwarder, parameters);
	}

	/**
	 * Set a strategy on the forwarder; see
	 * http://named-data.net/doc/NFD/current/manpages/nfdc.html for command-line
	 * usage and http://redmine.named-data.net/projects/nfd/wiki/StrategyChoice
	 * for protocol documentation. Ensure the forwarding face is on the local
	 * machine (management requests are to /localhost/...) and that command
	 * signing has been set up (e.g. forwarder.setCommandSigningInfo()).
	 *
	 * @param forwarder Only a localhost Face
	 * @param prefix
	 * @param strategy
	 * @return true for successful command
	 * @throws Exception
	 */
	public static boolean setStrategy(Face forwarder, Name prefix, Name strategy) throws Exception {
		// build command name
		Name command = new Name("/localhost/nfd/strategy-choice/set");
		ControlParameters parameters = new ControlParameters();
		parameters.setName(prefix);
		parameters.setStrategy(strategy);
		command.append(parameters.wireEncode());

		// send the interest
		return sendCommandAndErrorCheck(forwarder, new Interest(command));
	}

	/**
	 * Send an interest as a command to the forwarder; this method will convert
	 * the interest to a command interest and block until a response is received
	 * from the forwarder. Ensure the forwarding face is on the local machine
	 * (management requests are to /localhost/...) and that command signing has
	 * been set up (e.g. forwarder.setCommandSigningInfo()).
	 *
	 * @param forwarder Only a localhost Face
	 * @param interest As described at
	 * http://redmine.named-data.net/projects/nfd/wiki/ControlCommand, the
	 * requested interest must have encoded ControlParameters appended to the
	 * interest name
	 * @return
	 * @throws net.named_data.jndn.security.SecurityException
	 * @throws java.io.IOException
	 * @throws net.named_data.jndn.encoding.EncodingException
	 */
	public static ControlResponse sendCommand(Face forwarder, Interest interest) throws SecurityException, IOException, EncodingException {
		forwarder.makeCommandInterest(interest);

		// send command packet
		Data data = Client.getDefault().getSync(forwarder, interest);
		if (data == null) {
			throw new IOException("Failed to receive command response.");
		}

		// return response
		return ControlResponse.decode(data);
	}

	/**
	 * Send an interest as a command to the forwarder; this method will convert
	 * the interest to a command interest and block until a response is received
	 * from the forwarder.
	 *
	 * @param forwarder Only a localhost Face
	 * @param interest As described at
	 * http://redmine.named-data.net/projects/nfd/wiki/ControlCommand, the
	 * requested interest must have encoded ControlParameters appended to the
	 * interest name
	 * @return
	 * @throws net.named_data.jndn.security.SecurityException
	 * @throws java.io.IOException
	 * @throws net.named_data.jndn.encoding.EncodingException
	 */
	public static boolean sendCommandAndErrorCheck(Face forwarder, Interest interest) throws SecurityException, IOException, EncodingException {
		ControlResponse response = sendCommand(forwarder, interest);
		if (response.StatusCode < 400) {
			return true;
		} else {
			logger.warn("Command sent but failed: " + response.StatusCode + " " + response.StatusText);
			return false;
		}
	}
}