--- /dev/null
+/* Copyright (c) 2012-2014, 2016. The SimGrid Team.
+ * All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+package dht.kademlia;
+
+import org.simgrid.msg.Host;
+
+import org.simgrid.msg.Msg;
+import org.simgrid.msg.Comm;
+import org.simgrid.msg.Task;
+import org.simgrid.msg.Process;
+import org.simgrid.msg.MsgException;
+
+public class Node extends Process {
+ protected int id;
+ protected RoutingTable table;
+ protected int deadline;
+ protected int findNodeSuccedded = 0;
+ protected int findNodeFailed = 0;
+ protected Comm comm;
+
+ public Node(Host host, String name, String[]args) {
+ super(host,name,args);
+ }
+
+ @Override
+ public void main(String[] args) throws MsgException {
+ //Check the number of arguments.
+ if (args.length != 2 && args.length != 3) {
+ Msg.info("Wrong argument count.");
+ return;
+ }
+ this.id = Integer.valueOf(args[0]);
+ this.table = new RoutingTable(this.id);
+
+ if (args.length == 3) {
+ this.deadline = Integer.valueOf(args[2]).intValue();
+ Msg.info("Hi, I'm going to join the network with the id " + id + "!");
+ if (joinNetwork(Integer.valueOf(args[1]))) {
+ this.mainLoop();
+ }
+ else {
+ Msg.info("I couldn't join the network :(");
+ }
+ }
+ else {
+ this.deadline = Integer.valueOf(args[1]).intValue();
+ Msg.info("Hi, I'm going to create the network with the id " + id + "!");
+ table.update(this.id);
+ this.mainLoop();
+ }
+ Msg.debug("I'm leaving the network");
+ Msg.debug("Here is my routing table:" + table);
+ }
+
+ public void mainLoop() {
+ double next_lookup_time = Msg.getClock() + Common.RANDOM_LOOKUP_INTERVAL;
+ while (Msg.getClock() < this.deadline) {
+ try {
+ if (comm == null) {
+ comm = Task.irecv(Integer.toString(id));
+ }
+ if (!comm.test()) {
+ if (Msg.getClock() >= next_lookup_time) {
+ randomLookup();
+ next_lookup_time += Common.RANDOM_LOOKUP_INTERVAL;
+ } else {
+ waitFor(1);
+ }
+ } else {
+ Task task = comm.getTask();
+ handleTask(task);
+ comm = null;
+ }
+ }
+ catch (Exception e) {
+ }
+ }
+ Msg.info(findNodeSuccedded + "/" + (findNodeSuccedded + findNodeFailed) + " FIND_NODE have succedded.");
+ }
+
+ /**
+ * @brief Try to make the node join the network
+ * @param idKnown Id of someone we know in the system
+ */
+ public boolean joinNetwork(int idKnown) {
+ boolean answerGot = false;
+ double timeBegin = Msg.getClock();
+ Msg.debug("Joining the network knowing " + idKnown);
+ //Add ourselves and the node we know to our routing table
+ table.update(this.id);
+ table.update(idKnown);
+ //Send a "FIND_NODE" to the node we know.
+ sendFindNode(idKnown,this.id);
+ //Wait for the answer.
+ int trials = 0;
+
+ do {
+ try {
+ if (comm == null) {
+ comm = Task.irecv(Integer.toString(id));
+ }
+ if (comm != null) {
+ if (!comm.test()) {
+ waitFor(1);
+ } else {
+ Task task = comm.getTask();
+ if (task instanceof FindNodeAnswerTask) {
+ answerGot = true;
+ //Retrieve the node list and ping them
+ FindNodeAnswerTask answerTask = (FindNodeAnswerTask)task;
+ Answer answer = answerTask.getAnswer();
+ answerGot = true;
+ //answersGotten++;
+ if (answer.getDestinationId() == this.id) {
+ //Ping everyone in the list
+ for (Contact c : answer.getNodes()) {
+ table.update(c.getId());
+ }
+ }
+ } else {
+ handleTask(task);
+ }
+ comm = null;
+ }
+ }
+ }
+ catch (Exception ex) {
+ trials++;
+ Msg.info("FIND_NODE failed");
+ }
+ } while (!answerGot && trials < Common.MAX_JOIN_TRIALS);
+ /* Second step: Send a FIND_NODE in a node in each bucket */
+ int bucketId = table.findBucket(idKnown).getId();
+ for (int i = 0; ((bucketId - i) > 0 ||
+ (bucketId + i) <= Common.IDENTIFIER_SIZE) &&
+ i < Common.JOIN_BUCKETS_QUERIES; i++) {
+ if (bucketId - i > 0) {
+ int idInBucket = table.getIdInPrefix(this.id,bucketId - i);
+ this.findNode(idInBucket,false);
+ }
+ if (bucketId + i <= Common.IDENTIFIER_SIZE) {
+ int idInBucket = table.getIdInPrefix(this.id,bucketId + i);
+ findNode(idInBucket,false);
+ }
+ }
+ Msg.debug("Time spent:" + (Msg.getClock() - timeBegin));
+ return answerGot;
+ }
+
+ /* Send a request to find a node in the node's routing table. */
+ public boolean findNode(int destination, boolean counts) {
+ int queries, answers;
+ int nodesAdded = 0;
+ boolean destinationFound = false;
+ int steps = 0;
+ double timeBeginReceive;
+ double timeout, globalTimeout = Msg.getClock() + Common.FIND_NODE_GLOBAL_TIMEOUT;
+ //Build a list of the closest nodes we already know.
+ Answer nodeList = table.findClosest(destination);
+ Msg.verb("Doing a FIND_NODE on " + destination);
+ do {
+ timeBeginReceive = Msg.getClock();
+ answers = 0;
+ queries = this.sendFindNodeToBest(nodeList);
+ nodesAdded = 0;
+ timeout = Msg.getClock() + Common.FIND_NODE_TIMEOUT;
+ steps++;
+ do {
+ try {
+ if (comm == null) {
+ comm = Task.irecv(Integer.toString(id));
+ }
+ if (!comm.test()) {
+ waitFor(1);
+ } else {
+ Task task = comm.getTask();
+ if (task instanceof FindNodeAnswerTask) {
+ FindNodeAnswerTask answerTask = (FindNodeAnswerTask)task;
+ //Check if we received what we are looking for.
+ if (answerTask.getDestinationId() == destination) {
+ table.update(answerTask.getSenderId());
+ //Add the answer to our routing table
+ for (Contact c: answerTask.getAnswer().getNodes()) {
+ table.update(c.getId());
+ }
+ answers++;
+
+ nodesAdded = nodeList.merge(answerTask.getAnswer());
+ } else {
+ /* If it's not our answer, we answer to the node that has queried us anyway */
+ handleTask(task);
+ //Update the timeout if it's not our answer.
+ timeout += Msg.getClock() - timeBeginReceive;
+ timeBeginReceive = Msg.getClock();
+ }
+ } else {
+ handleTask(task);
+ timeout += Msg.getClock() - timeBeginReceive;
+ timeBeginReceive = Msg.getClock();
+ }
+ comm = null;
+ }
+ }
+ catch (Exception e) {
+ comm = null;
+ }
+ } while (answers < queries && Msg.getClock() < timeout);
+ destinationFound = nodeList.destinationFound();
+ } while (!destinationFound && (nodesAdded > 0 || answers == 0) && Msg.getClock() < globalTimeout
+ && steps < Common.MAX_STEPS);
+
+ if (destinationFound) {
+ if (counts) {
+ findNodeSuccedded++;
+ }
+ Msg.debug("Find node on " + destination + " succedded");
+ } else {
+ Msg.debug("Find node on " + destination + " failed");
+ Msg.debug("Queried " + queries + " nodes to find " + destination);
+ Msg.debug(nodeList.toString());
+ if (counts) {
+ findNodeFailed++;
+ }
+ }
+ return destinationFound;
+ }
+
+ /**
+ * @brief Sends a "PING" request to a node
+ * @param destination Ping destination id.
+ */
+ public void ping(int destination) {
+ boolean destinationFound = false;
+ double timeout = Msg.getClock() + Common.PING_TIMEOUT;
+ PingTask pingTask = new PingTask(this.id);
+ /* Sending the ping task */
+ pingTask.dsend(Integer.toString(destination));
+ do {
+ try {
+ Task task = Task.receive(Integer.toString(this.id),Common.PING_TIMEOUT);
+ if (task instanceof PingAnswerTask) {
+ PingAnswerTask answerTask = (PingAnswerTask)task;
+ if (answerTask.getSenderId() == destination) {
+ this.table.update(destination);
+ destinationFound = true;
+ } else {
+ handleTask(task);
+ }
+ } else {
+ handleTask(task);
+ }
+ waitFor(1);
+ }
+ catch (Exception ex) {
+ }
+ } while (Msg.getClock() < timeout && !destinationFound);
+ }
+
+ /**
+ * @brief Sends a "FIND_NODE" request (task) to a node we know.
+ * @param id Id of the node we are querying
+ * @param destination id of the node we are trying to find.
+ */
+ public void sendFindNode(int id, int destination) {
+ Msg.debug("Sending a FIND_NODE to " + Integer.toString(id) + " to find " + destination );
+ FindNodeTask task = new FindNodeTask(this.id,destination);
+ task.dsend(Integer.toString(id));
+ }
+
+ /** Sends a "FIND_NODE" request to the best "alpha" nodes in a node list */
+ public int sendFindNodeToBest(Answer nodeList) {
+ int destination = nodeList.getDestinationId();
+ int i;
+ for (i = 0; i < Common.alpha && i < nodeList.size(); i++) {
+ Contact node = nodeList.getNodes().get(i);
+ if (node.getId() != this.id) {
+ this.sendFindNode(node.getId(),destination);
+ }
+ }
+ return i;
+ }
+
+ public void randomLookup() {
+ findNode(0,true);
+ }
+
+ /**
+ * @brief Handles an incomming task
+ * @param task The task we need to handle
+ */
+ public void handleTask(Task task) {
+ if (task instanceof KademliaTask) {
+ table.update(((KademliaTask) task).getSenderId());
+ if (task instanceof FindNodeTask) {
+ handleFindNode((FindNodeTask)task);
+ }
+ else if (task instanceof PingTask) {
+ handlePing((PingTask)task);
+ }
+ }
+ }
+
+ public void handleFindNode(FindNodeTask task) {
+ Msg.debug("Received a FIND_NODE from " + task.getSenderId());
+ Answer answer = table.findClosest(task.getDestination());
+ FindNodeAnswerTask taskToSend = new FindNodeAnswerTask(this.id,task.getDestination(),answer);
+ taskToSend.dsend(Integer.toString(task.getSenderId()));
+ }
+
+ public void handlePing(PingTask task) {
+ Msg.debug("Received a PING from " + task.getSenderId());
+ PingAnswerTask taskToSend = new PingAnswerTask(this.id);
+ taskToSend.dsend(Integer.toString(task.getSenderId()));
+ }
+}
