+++ /dev/null
-/* Copyright (c) 2006-2019. 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 app.bittorrent;
-
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.Map.Entry;
-
-import org.simgrid.msg.Msg;
-import org.simgrid.msg.Comm;
-import org.simgrid.msg.Host;
-import org.simgrid.msg.Task;
-import org.simgrid.msg.Process;
-import org.simgrid.msg.RngStream;
-import org.simgrid.msg.MsgException;
-
-public class Peer extends Process {
- protected int round = 0;
- protected double beginReceiveTime;
- protected double deadline;
- protected static RngStream stream = new RngStream();
- protected int id;
- protected String mailbox;
- protected String mailboxTracker;
- protected String hostname;
- protected int pieces = 0;
- protected char[] bitfield = new char[Common.FILE_PIECES];
- protected char[][] bitfieldBlocks = new char[Common.FILE_PIECES][Common.PIECES_BLOCKS];
- protected short[] piecesCount = new short[Common.FILE_PIECES];
- protected int piecesRequested = 0;
- protected ArrayList<Integer> currentPieces = new ArrayList<>();
- protected int currentPiece = -1;
- protected HashMap<Integer, Connection> activePeers = new HashMap<>();
- protected HashMap<Integer, Connection> peers = new HashMap<>();
- protected Comm commReceived = null;
-
- public Peer(Host host, String name, String[]args) {
- super(host,name,args);
- }
-
- @Override
- public void main(String[] args) throws MsgException {
- //Check arguments
- if (args.length != 3 && args.length != 2) {
- Msg.info("Wrong number of arguments");
- }
- if (args.length == 3) {
- init(Integer.parseInt(args[0]),true);
- } else {
- init(Integer.parseInt(args[0]),false);
- }
- //Retrieve the deadline
- deadline = Double.parseDouble(args[1]);
- if (deadline < 0) {
- Msg.info("Wrong deadline supplied");
- return;
- }
- Msg.info("Hi, I'm joining the network with id " + id);
- //Getting peer data from the tracker
- if (getPeersData()) {
- Msg.debug("Got " + peers.size() + " peers from the tracker");
- Msg.debug("Here is my current status: " + getStatus());
- beginReceiveTime = Msg.getClock();
- if (hasFinished()) {
- pieces = Common.FILE_PIECES;
- sendHandshakeAll();
- seedLoop();
- } else {
- leechLoop();
- seedLoop();
- }
- } else {
- Msg.info("Couldn't contact the tracker.");
- }
- Msg.info("Here is my current status: " + getStatus());
- }
-
- private void leechLoop() {
- double nextChokedUpdate = Msg.getClock() + Common.UPDATE_CHOKED_INTERVAL;
- Msg.debug("Start downloading.");
- // Send a "handshake" message to all the peers it got(it couldn't have gotten more than 50 peers anyway)
- sendHandshakeAll();
- //Wait for at least one "bitfield" message.
- waitForPieces();
- Msg.debug("Starting main leech loop");
- while (Msg.getClock() < deadline && pieces < Common.FILE_PIECES) {
- if (commReceived == null) {
- commReceived = Task.irecv(mailbox);
- }
- try {
- if (commReceived.test()) {
- handleMessage(commReceived.getTask());
- commReceived = null;
- } else {
- //If the user has a pending interesting
- if (currentPiece != -1) {
- sendInterestedToPeers();
- } else {
- if (currentPieces.size() < Common.MAX_PIECES) {
- updateCurrentPiece();
- }
- }
- //We don't execute the choke algorithm if we don't already have a piece
- if (Msg.getClock() >= nextChokedUpdate && pieces > 0) {
- updateChokedPeers();
- nextChokedUpdate += Common.UPDATE_CHOKED_INTERVAL;
- } else {
- waitFor(1);
- }
- }
- }
- catch (MsgException e) {
- e.printStackTrace();
- commReceived = null;
- }
- }
- }
-
- private void seedLoop() {
- double nextChokedUpdate = Msg.getClock() + Common.UPDATE_CHOKED_INTERVAL;
- Msg.debug("Start seeding.");
- //start the main seed loop
- while (Msg.getClock() < deadline) {
- if (commReceived == null) {
- commReceived = Task.irecv(mailbox);
- }
- try {
- if (commReceived.test()) {
- handleMessage(commReceived.getTask());
- commReceived = null;
- } else {
- if (Msg.getClock() >= nextChokedUpdate) {
- updateChokedPeers();
- //TODO: Change the choked peer algorithm when seeding
- nextChokedUpdate += Common.UPDATE_CHOKED_INTERVAL;
- } else {
- waitFor(1);
- }
- }
- }
- catch (MsgException e) {
- commReceived = null;
- }
- }
- }
-
- /**
- * @brief Initialize the various peer data
- * @param id id of the peer to take in the network
- * @param seed indicates if the peer is a seed
- */
- private void init(int id, boolean seed) {
- this.id = id;
- this.mailbox = Integer.toString(id);
- this.mailboxTracker = "tracker_" + Integer.toString(id);
- if (seed) {
- for (int i = 0; i < bitfield.length; i++) {
- bitfield[i] = '1';
- for (int j = 0; j < bitfieldBlocks[i].length; j++) {
- bitfieldBlocks[i][j] = '1';
- }
- }
- } else {
- for (int i = 0; i < bitfield.length; i++) {
- bitfield[i] = '0';
- for (int j = 0; j < bitfieldBlocks[i].length; j++) {
- bitfieldBlocks[i][j] = '0' ;
- }
- }
- }
- this.hostname = getHost().getName();
- }
-
- private boolean getPeersData() {
- boolean success = false;
- double timeout = Msg.getClock() + Common.GET_PEERS_TIMEOUT;
- //Build the task to send to the tracker
- TrackerTask taskSend = new TrackerTask(hostname, mailboxTracker, id);
-
- while (Msg.getClock() < timeout) {
- try {
- Msg.debug("Sending a peer request to the tracker.");
- taskSend.send(Common.TRACKER_MAILBOX,Common.GET_PEERS_TIMEOUT);
- break;
- }
- catch (MsgException e) {
- e.printStackTrace();
- }
- }
- while (!success && Msg.getClock() < timeout) {
- commReceived = Task.irecv(this.mailboxTracker);
- try {
- commReceived.waitCompletion(Common.GET_PEERS_TIMEOUT);
- if (commReceived.getTask() instanceof TrackerTask) {
- TrackerTask task = (TrackerTask)commReceived.getTask();
- for (Integer peerId: task.peers) {
- if (peerId != this.id) {
- peers.put(peerId, new Connection(peerId));
- }
- }
- success = true;
- }
- }
- catch (MsgException e) {
- e.printStackTrace();
- }
- commReceived = null;
- }
- return success;
- }
-
- private void handleMessage(Task task) {
- MessageTask message = (MessageTask)task;
- Connection remotePeer = peers.get(message.peerId);
- switch (message.type) {
- case HANDSHAKE:
- Msg.debug("Received a HANDSHAKE message from " + message.mailbox);
- //Check if the peer is in our connection list
- if (remotePeer == null) {
- peers.put(message.peerId, new Connection(message.peerId));
- sendHandshake(message.mailbox);
- }
- //Send our bitfield to the pair
- sendBitfield(message.mailbox);
- break;
- case BITFIELD:
- Msg.debug("Received a BITFIELD message from " + message.peerId + " (" + message.issuerHostname + ")");
- //update the pieces list
- updatePiecesCountFromBitfield(message.bitfield);
- //Update the current piece
- if (currentPiece == -1 && pieces < Common.FILE_PIECES && currentPieces.size() < Common.MAX_PIECES) {
- updateCurrentPiece();
- }
- remotePeer.bitfield = message.bitfield.clone();
- break;
- case INTERESTED:
- Msg.debug("Received an INTERESTED message from " + message.peerId + " (" + message.issuerHostname + ")");
- assert remotePeer != null;
- remotePeer.interested = true;
- break;
- case NOTINTERESTED:
- Msg.debug("Received a NOTINTERESTED message from " + message.peerId + " (" + message.issuerHostname + ")");
- assert remotePeer != null;
- remotePeer.interested = false;
- break;
- case UNCHOKE:
- Msg.debug("Received an UNCHOKE message from " + message.peerId + "(" + message.issuerHostname + ")");
- assert remotePeer != null;
- remotePeer.chokedDownload = false;
- activePeers.put(remotePeer.id,remotePeer);
- sendRequestsToPeer(remotePeer);
- break;
- case CHOKE:
- Msg.debug("Received a CHOKE message from " + message.peerId + " (" + message.issuerHostname + ")");
- assert remotePeer != null;
- remotePeer.chokedDownload = true;
- activePeers.remove(remotePeer.id);
- break;
- case HAVE:
- if (remotePeer.bitfield == null) {
- return;
- }
- Msg.debug("Received a HAVE message from " + message.peerId + " (" + message.issuerHostname + ")");
- assert message.index >= 0 && message.index < Common.FILE_PIECES;
- assert remotePeer.bitfield != null;
- remotePeer.bitfield[message.index] = '1';
- piecesCount[message.index]++;
- //Send interested message to the peer if he has what we want
- if (!remotePeer.amInterested && currentPieces.contains(message.index) ) {
- remotePeer.amInterested = true;
- sendInterested(remotePeer.mailbox);
- }
-
- if (currentPieces.contains(message.index)) {
- int blockIndex = getFirstBlock(message.index);
- int blockLength = Common.PIECES_BLOCKS - blockIndex ;
- blockLength = blockLength > Common.BLOCKS_REQUESTED ? Common.BLOCKS_REQUESTED : blockLength;
- sendRequest(message.mailbox,message.index,blockIndex,blockLength);
- }
- break;
- case REQUEST:
- assert message.index >= 0 && message.index < Common.FILE_PIECES;
- if (!remotePeer.chokedUpload) {
- Msg.debug("Received a REQUEST from " + message.peerId + "(" + message.issuerHostname + ") for "
- + message.peerId);
- if (bitfield[message.index] == '1') {
- sendPiece(message.mailbox,message.index,false,message.blockIndex,message.blockLength);
- } else {
- Msg.debug("Received a REQUEST from " + message.peerId + " (" + message.issuerHostname
- + ") but he is choked" );
- }
- }
- break;
- case PIECE:
- if (message.stalled) {
- Msg.debug("The received piece " + message.index + " from " + message.peerId + " (" + message.issuerHostname
- + ") is stalled");
- } else {
- Msg.debug("Received piece " + message.index + " from " + message.peerId + " ("
- + message.issuerHostname + ")");
- if (bitfield[message.index] == '0') {
- updateBitfieldBlocks(message.index,message.blockIndex,message.blockLength);
- if (pieceComplete(message.index)) {
- piecesRequested--;
- //Removing the piece from our piece list.
- currentPieces.remove((Object)Integer.valueOf(message.index));
- //Setting the fact that we have the piece
- bitfield[message.index] = '1';
- pieces++;
- Msg.debug("My status is now " + getStatus());
- //Sending the information to all the peers we are connected to
- sendHave(message.index);
- //sending UNINTERESTED to peers that doesn't have what we want.
- updateInterestedAfterReceive();
- }
- } else {
- Msg.debug("However, we already have it.");
- }
- }
- break;
- default:
- Msg.error("Unexpected message type: " + message.type);
- break;
- }
- if (remotePeer != null) {
- remotePeer.addSpeedValue(1 / (Msg.getClock() - beginReceiveTime));
- }
- beginReceiveTime = Msg.getClock();
- }
-
- private void waitForPieces() {
- boolean finished = false;
- while (Msg.getClock() < deadline && !finished) {
- if (commReceived == null) {
- commReceived = Task.irecv(mailbox);
- }
- try {
- commReceived.waitCompletion(Common.TIMEOUT_MESSAGE);
- handleMessage(commReceived.getTask());
- if (currentPiece != -1) {
- finished = true;
- }
- commReceived = null;
- }
- catch (MsgException e) {
- commReceived = null;
- }
- }
- }
-
- private boolean hasFinished() {
- for (int i = 0; i < bitfield.length; i++) {
- if (bitfield[i] == '1') {
- return true;
- }
- }
- return false;
- }
-
- /**
- * @brief Updates the list of who has a piece from a bitfield
- * @param bitfield bitfield
- */
- private void updatePiecesCountFromBitfield(char[] bitfield) {
- for (int i = 0; i < Common.FILE_PIECES; i++) {
- if (bitfield[i] == '1') {
- piecesCount[i]++;
- }
- }
- }
-
- /**
- * Update the piece the peer is currently interested in.
- * There is two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
- * If the peer has less than 3 pieces, he chooses a piece at random.
- * If the peer has more than pieces, he downloads the pieces that are the less
- * replicated
- */
- private void updateCurrentPiece() {
- if (currentPieces.size() >= (Common.FILE_PIECES - pieces)) {
- return;
- }
-
- //TODO: trivial min algorithm when pieces >= 3
- do {
- currentPiece = stream.randInt(0,Common.FILE_PIECES - 1);
- } while (!(bitfield[currentPiece] == '0' && !currentPieces.contains(currentPiece)));
-
- currentPieces.add(currentPiece);
- Msg.debug("New interested piece: " + currentPiece);
- assert currentPiece >= 0 && currentPiece < Common.FILE_PIECES;
- }
-
- // Update the list of current choked and unchoked peers, using the choke algorithm
- private void updateChokedPeers() {
- round = (round + 1) % 3;
- if (peers.size() == 0) {
- return;
- }
- //remove a peer from the list
- Iterator<Entry<Integer, Connection>> it = activePeers.entrySet().iterator();
- if (it.hasNext()) {
- Entry<Integer,Connection> e = it.next();
- Connection peerChoked = e.getValue();
- peerChoked.chokedUpload = true;
- sendChoked(peerChoked.mailbox);
- activePeers.remove(e.getKey());
- }
- Connection peerChoosed = null;
- //Separate the case from when the peer is seeding.
- if (pieces == Common.FILE_PIECES) {
- //Find the last unchoked peer.
- double unchokeTime = deadline + 1;
- for (Connection connection : peers.values()) {
- if (connection.lastUnchoke < unchokeTime && connection.interested) {
- peerChoosed = connection;
- unchokeTime = connection.lastUnchoke;
- }
- }
- } else {
- //Random optimistic unchoking
- if (round == 0) {
- int j = 0;
- do {
- int i = 0;
- int idChosen = stream.randInt(0,peers.size() - 1);
- for (Connection connection : peers.values()) {
- if (i == idChosen) {
- peerChoosed = connection;
- break;
- }
- i++;
- } //TODO: Not really the best way ever
- if (peerChoosed != null && !peerChoosed.interested) {
- peerChoosed = null;
- }
- j++;
- } while (peerChoosed == null && j < Common.MAXIMUM_PEERS);
- } else {
- Connection fastest = null;
- double fastestSpeed = 0;
- for (Connection c : peers.values()) {
- if (c.peerSpeed > fastestSpeed && c.interested && c.chokedUpload) {
- fastest = c;
- fastestSpeed = c.peerSpeed;
- }
- }
- peerChoosed = fastest;
- }
- }
- if (peerChoosed != null) {
- activePeers.put(peerChoosed.id,peerChoosed);
- peerChoosed.chokedUpload = false;
- peerChoosed.lastUnchoke = Msg.getClock();
- sendUnchoked(peerChoosed.mailbox);
- }
- }
-
- // Updates our "interested" state about peers: send "not interested" to peers that don't have any more pieces we want.
- private void updateInterestedAfterReceive() {
- boolean interested;
- for (Connection connection : peers.values()) {
- interested = false;
- if (connection.amInterested) {
- for (Integer piece : currentPieces) {
- if (connection.bitfield[piece] == '1') {
- interested = true;
- break;
- }
- }
- if (!interested) {
- connection.amInterested = false;
- sendNotInterested(connection.mailbox);
- }
- }
- }
- }
-
- private void updateBitfieldBlocks(int index, int blockIndex, int blockLength) {
- for (int i = blockIndex; i < (blockIndex + blockLength); i++) {
- bitfieldBlocks[index][i] = '1';
- }
- }
-
- // Returns if a piece is complete in the peer's bitfield.
- private boolean pieceComplete(int index) {
- for (int i = 0; i < bitfieldBlocks[index].length; i++) {
- if (bitfieldBlocks[index][i] == '0') {
- return false;
- }
- }
- return true;
- }
-
- // Returns the first block of a piece that we don't have.
- private int getFirstBlock(int piece) {
- int blockIndex = -1;
- for (int i = 0; i < Common.PIECES_BLOCKS; i++) {
- if (bitfieldBlocks[piece][i] == '0') {
- blockIndex = i;
- break;
- }
- }
- return blockIndex;
- }
-
- /**
- * @brief Send request messages to a peer that have unchoked us
- * @param remotePeer peer data to the peer we want to send the request
- */
- private void sendRequestsToPeer(Connection remotePeer) {
- if (remotePeer.bitfield == null) {
- return;
- }
- for (Integer piece : currentPieces) {
- //Getting the block to send.
- int blockIndex = getFirstBlock(piece);
- int blockLength = Common.PIECES_BLOCKS - blockIndex ;
- blockLength = blockLength > Common.BLOCKS_REQUESTED ? Common.BLOCKS_REQUESTED : blockLength;
- if (remotePeer.bitfield[piece] == '1') {
- sendRequest(remotePeer.mailbox, piece, blockIndex, blockLength);
- }
- }
- }
-
- // Find the peers that have the current interested piece and send them the "interested" message
- private void sendInterestedToPeers() {
- if (currentPiece == -1) {
- return;
- }
- for (Connection connection : peers.values()) {
- if (connection.bitfield != null && connection.bitfield[currentPiece] == '1' && !connection.amInterested) {
- connection.amInterested = true;
- MessageTask task = new MessageTask(MessageTask.Type.INTERESTED, hostname, this.mailbox, this.id);
- task.dsend(connection.mailbox);
- }
- }
- currentPiece = -1;
- piecesRequested++;
- }
-
- // Send a "interested" message to a peer.
- private void sendInterested(String mailbox) {
- MessageTask task = new MessageTask(MessageTask.Type.INTERESTED, hostname, this.mailbox, this.id);
- task.dsend(mailbox);
- }
-
- /**
- * @brief Send a "not interested" message to a peer
- * @param mailbox mailbox destination mailbox
- */
- private void sendNotInterested(String mailbox) {
- MessageTask task = new MessageTask(MessageTask.Type.NOTINTERESTED, hostname, this.mailbox, this.id);
- task.dsend(mailbox);
- }
-
- // Send a handshake message to all the peers the peer has.
- private void sendHandshakeAll() {
- for (Connection remotePeer : peers.values()) {
- MessageTask task = new MessageTask(MessageTask.Type.HANDSHAKE, hostname, mailbox, id);
- task.dsend(remotePeer.mailbox);
- }
- }
-
- /**
- * @brief Send a "handshake" message to an user
- * @param mailbox mailbox where to we send the message
- */
- private void sendHandshake(String mailbox) {
- Msg.debug("Sending a HANDSHAKE to " + mailbox);
- MessageTask task = new MessageTask(MessageTask.Type.HANDSHAKE, hostname, this.mailbox, this.id);
- task.dsend(mailbox);
- }
-
- // Send a "choked" message to a peer
- private void sendChoked(String mailbox) {
- Msg.debug("Sending a CHOKE to " + mailbox);
- MessageTask task = new MessageTask(MessageTask.Type.CHOKE, hostname, this.mailbox, this.id);
- task.dsend(mailbox);
- }
-
- // Send a "unchoked" message to a peer
- private void sendUnchoked(String mailbox) {
- Msg.debug("Sending a UNCHOKE to " + mailbox);
- MessageTask task = new MessageTask(MessageTask.Type.UNCHOKE, hostname, this.mailbox, this.id);
- task.dsend(mailbox);
- }
-
- // Send a "HAVE" message to all peers we are connected to
- private void sendHave(int piece) {
- Msg.debug("Sending HAVE message to all my peers");
- for (Connection remotePeer : peers.values()) {
- MessageTask task = new MessageTask(MessageTask.Type.HAVE, hostname, this.mailbox, this.id, piece);
- task.dsend(remotePeer.mailbox);
- }
- }
- // Send a bitfield message to all the peers the peer has.
- private void sendBitfield(String mailbox) {
- Msg.debug("Sending a BITFIELD to " + mailbox);
- MessageTask task = new MessageTask(MessageTask.Type.BITFIELD, hostname, this.mailbox, this.id, this.bitfield);
- task.dsend(mailbox);
- }
- // Send a "request" message to a peer, containing a request for a piece
- private void sendRequest(String mailbox, int piece, int blockIndex, int blockLength) {
- Msg.debug("Sending a REQUEST to " + mailbox + " for piece " + piece + " and blocks " + blockIndex + ","
- + (blockIndex + blockLength));
- MessageTask task = new MessageTask(MessageTask.Type.REQUEST, hostname, this.mailbox, this.id, piece, blockIndex,
- blockLength);
- task.dsend(mailbox);
- }
-
- // Send a "piece" message to a peer, containing a piece of the file
- private void sendPiece(String mailbox, int piece, boolean stalled, int blockIndex, int blockLength) {
- Msg.debug("Sending the PIECE " + piece + " to " + mailbox);
- MessageTask task = new MessageTask(MessageTask.Type.PIECE, hostname, this.mailbox, this.id, piece, stalled,
- blockIndex, blockLength);
- task.dsend(mailbox);
- }
-
- private String getStatus() {
- StringBuilder s = new StringBuilder("");
- for (int i = 0; i < Common.FILE_PIECES; i++)
- s.append(bitfield[i]);
- return s.toString();
- }
-}
