+++ /dev/null
-/* Copyright (c) 2012-2017. 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. */
-
-#include "peer.h"
-#include "tracker.h"
-#include "connection.h"
-#include "messages.h"
-#include <simgrid/msg.h>
-#include <xbt/RngStream.h>
-#include <limits.h>
-
-XBT_LOG_NEW_DEFAULT_CATEGORY(msg_peers, "Messages specific for the peers");
-
-/*
- * User parameters for transferred file data. For the test, the default values are :
- * File size: 10 pieces * 5 blocks/piece * 16384 bytes/block = 819200 bytes
- */
-#define FILE_PIECES 10UL
-#define PIECES_BLOCKS 5UL
-#define BLOCK_SIZE 16384
-static const unsigned long int FILE_SIZE = FILE_PIECES * PIECES_BLOCKS * BLOCK_SIZE;
-
-/** Number of blocks asked by each request */
-#define BLOCKS_REQUESTED 2
-
-#define ENABLE_END_GAME_MODE 1
-#define SLEEP_DURATION 1
-
-int count_pieces(unsigned int bitfield){
- int count=0;
- unsigned int n = bitfield;
- while (n){
- count += n & 1U;
- n >>= 1U ;
- }
- return count;
-}
-
-int peer_has_not_piece(peer_t peer, unsigned int piece){
- return !(peer->bitfield & 1U<<piece);
-}
-
-/** Check that a piece is not currently being download by the peer. */
-int peer_is_not_downloading_piece(peer_t peer, unsigned int piece){
- return !(peer->current_pieces & 1U<<piece);
-}
-
-void get_status(char **status, unsigned int bitfield){
- for(int i=FILE_PIECES-1; i>=0; i--)
- (*status)[i] = (bitfield & (1U << i)) ? '1' : '0';
- (*status)[FILE_PIECES] = '\0';
-}
-
-/** Peer main function */
-int peer(int argc, char *argv[])
-{
- //Check arguments
- xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
-
- //Build peer object
- peer_t peer = peer_init(xbt_str_parse_int(argv[1],"Invalid ID: %s"), argc==4 ? 1:0);
-
- //Retrieve deadline
- double deadline = xbt_str_parse_double(argv[2],"Invalid deadline: %s");
- xbt_assert(deadline > 0, "Wrong deadline supplied");
-
- char *status = xbt_malloc0(FILE_PIECES+1);
- get_status(&status, peer->bitfield);
- XBT_INFO("Hi, I'm joining the network with id %d", peer->id);
- //Getting peer data from the tracker.
- if (get_peers_data(peer)) {
- XBT_DEBUG("Got %d peers from the tracker. Current status is: %s", xbt_dict_length(peer->peers), status);
- peer->begin_receive_time = MSG_get_clock();
- MSG_mailbox_set_async(peer->mailbox);
- if (has_finished(peer->bitfield)) {
- send_handshake_all(peer);
- } else {
- leech_loop(peer, deadline);
- }
- seed_loop(peer, deadline);
- } else {
- XBT_INFO("Couldn't contact the tracker.");
- }
-
- get_status(&status, peer->bitfield);
- XBT_INFO("Here is my current status: %s", status);
- if (peer->comm_received) {
- MSG_comm_destroy(peer->comm_received);
- }
-
- xbt_free(status);
- peer_free(peer);
- return 0;
-}
-
-/** @brief Peer main loop when it is leeching.
- * @param peer peer data
- * @param deadline time at which the peer has to leave
- */
-void leech_loop(peer_t peer, double deadline)
-{
- double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
- XBT_DEBUG("Start downloading.");
-
- /* Send a "handshake" message to all the peers it got (since it couldn't have gotten more than 50 peers) */
- send_handshake_all(peer);
- XBT_DEBUG("Starting main leech loop");
-
- while (MSG_get_clock() < deadline && count_pieces(peer->bitfield) < FILE_PIECES) {
- if (peer->comm_received == NULL) {
- peer->task_received = NULL;
- peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
- }
- if (MSG_comm_test(peer->comm_received)) {
- msg_error_t status = MSG_comm_get_status(peer->comm_received);
- MSG_comm_destroy(peer->comm_received);
- peer->comm_received = NULL;
- if (status == MSG_OK) {
- handle_message(peer, peer->task_received);
- }
- } else {
- //We don't execute the choke algorithm if we don't already have a piece
- if (MSG_get_clock() >= next_choked_update && count_pieces(peer->bitfield) > 0) {
- update_choked_peers(peer);
- next_choked_update += UPDATE_CHOKED_INTERVAL;
- } else {
- MSG_process_sleep(SLEEP_DURATION);
- }
- }
- }
- if (has_finished(peer->bitfield))
- XBT_DEBUG("%d becomes a seeder", peer->id);
-}
-
-/** @brief Peer main loop when it is seeding
- * @param peer peer data
- * @param deadline time when the peer will leave
- */
-void seed_loop(peer_t peer, double deadline)
-{
- double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
- XBT_DEBUG("Start seeding.");
- //start the main seed loop
- while (MSG_get_clock() < deadline) {
- if (peer->comm_received == NULL) {
- peer->task_received = NULL;
- peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
- }
- if (MSG_comm_test(peer->comm_received)) {
- msg_error_t status = MSG_comm_get_status(peer->comm_received);
- MSG_comm_destroy(peer->comm_received);
- peer->comm_received = NULL;
- if (status == MSG_OK) {
- handle_message(peer, peer->task_received);
- }
- } else {
- if (MSG_get_clock() >= next_choked_update) {
- update_choked_peers(peer);
- //TODO: Change the choked peer algorithm when seeding.
- next_choked_update += UPDATE_CHOKED_INTERVAL;
- } else {
- MSG_process_sleep(SLEEP_DURATION);
- }
- }
- }
-}
-
-/** @brief Retrieves the peer list from the tracker
- * @param peer current peer data
- */
-int get_peers_data(peer_t peer)
-{
- int success = 0;
- double timeout = MSG_get_clock() + GET_PEERS_TIMEOUT;
-
- //Build the task to send to the tracker
- tracker_task_data_t data = tracker_task_data_new(MSG_host_get_name(MSG_host_self()), peer->mailbox_tracker,
- peer->id, 0, 0, FILE_SIZE);
- msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
- while ((success == 0) && MSG_get_clock() < timeout) {
- XBT_DEBUG("Sending a peer request to the tracker.");
- msg_error_t status = MSG_task_send_with_timeout(task_send, TRACKER_MAILBOX, GET_PEERS_TIMEOUT);
- if (status == MSG_OK) {
- success = 1;
- }
- }
-
- success = 0;
- msg_task_t task_received = NULL;
- while ((success == 0) && MSG_get_clock() < timeout) {
- msg_comm_t comm_received = MSG_task_irecv(&task_received, peer->mailbox_tracker);
- msg_error_t status = MSG_comm_wait(comm_received, GET_PEERS_TIMEOUT);
- if (status == MSG_OK) {
- tracker_task_data_t data = MSG_task_get_data(task_received);
- unsigned i;
- int peer_id;
- //Add the peers the tracker gave us to our peer list.
- xbt_dynar_foreach(data->peers, i, peer_id) {
- if (peer_id != peer->id)
- xbt_dict_set_ext(peer->peers, (char *) &peer_id, sizeof(int), connection_new(peer_id), NULL);
- }
- success = 1;
- //free the communication and the task
- MSG_comm_destroy(comm_received);
- tracker_task_data_free(data);
- MSG_task_destroy(task_received);
- }
- }
-
- return success;
-}
-
-/** @brief Initialize the peer data.
- * @param peer peer data
- * @param id id of the peer to take in the network
- * @param seed indicates if the peer is a seed.
- */
-peer_t peer_init(int id, int seed)
-{
- peer_t peer = xbt_new(s_peer_t,1);
- peer->id = id;
- peer->hostname = MSG_host_get_name(MSG_host_self());
-
- snprintf(peer->mailbox,MAILBOX_SIZE-1, "%d", id);
- snprintf(peer->mailbox_tracker,MAILBOX_SIZE-1, "tracker_%d", id);
- peer->peers = xbt_dict_new_homogeneous(NULL);
- peer->active_peers = xbt_dict_new_homogeneous(NULL);
-
- if (seed) {
- peer->bitfield = (1U<<FILE_PIECES)-1U;
- peer->bitfield_blocks = (1ULL<<(FILE_PIECES * PIECES_BLOCKS))-1ULL ;
- } else {
- peer->bitfield = 0;
- peer->bitfield_blocks = 0;
- }
-
- peer->current_pieces = 0;
-
- peer->pieces_count = xbt_new0(short, FILE_PIECES);
-
- peer->stream = (RngStream)MSG_host_get_data(MSG_host_self());
- peer->comm_received = NULL;
-
- peer->round = 0;
-
- return peer;
-}
-
-/** Destroys a poor peer object. */
-void peer_free(peer_t peer)
-{
- char *key;
- connection_t connection;
- xbt_dict_cursor_t cursor;
- xbt_dict_foreach(peer->peers, cursor, key, connection) {
- connection_free(connection);
- }
- xbt_dict_free(&peer->peers);
- xbt_dict_free(&peer->active_peers);
- xbt_free(peer->pieces_count);
- xbt_free(peer);
-}
-
-/** @brief Returns if a peer has finished downloading the file
- * @param bitfield peer bitfield
- */
-int has_finished(unsigned int bitfield)
-{
- return bitfield == (1U<<FILE_PIECES)-1U;
-}
-
-int nb_interested_peers(peer_t peer)
-{
- xbt_dict_cursor_t cursor = NULL;
- char *key;
- connection_t connection;
- int nb = 0;
- xbt_dict_foreach(peer->peers, cursor, key, connection) {
- if (connection->interested)
- nb++;
- }
- return nb;
-}
-
-void update_active_peers_set(peer_t peer, connection_t remote_peer)
-{
- if ((remote_peer->interested != 0) && (remote_peer->choked_upload == 0)) {
- //add in the active peers set
- xbt_dict_set_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int), remote_peer, NULL);
- } else if (xbt_dict_get_or_null_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int))) {
- xbt_dict_remove_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int));
- }
-}
-
-/** @brief Handle a received message sent by another peer
- * @param peer Peer data
- * @param task task received.
- */
-void handle_message(peer_t peer, msg_task_t task)
-{
- const char* type_names[10] =
- {"HANDSHAKE","CHOKE","UNCHOKE","INTERESTED","NOTINTERESTED","HAVE","BITFIELD","REQUEST", "PIECE", "CANCEL" };
- message_t message = MSG_task_get_data(task);
- XBT_DEBUG("Received a %s message from %s (%s)", type_names[message->type], message->mailbox,
- message->issuer_host_name);
-
- connection_t remote_peer;
- remote_peer = xbt_dict_get_or_null_ext(peer->peers, (char *) &message->peer_id, sizeof(int));
-
- switch (message->type) {
- case MESSAGE_HANDSHAKE:
- //Check if the peer is in our connection list.
- if (remote_peer == 0) {
- xbt_dict_set_ext(peer->peers, (char *) &message->peer_id, sizeof(int), connection_new(message->peer_id), NULL);
- send_handshake(peer, message->mailbox);
- }
- //Send our bitfield to the peer
- send_bitfield(peer, message->mailbox);
- break;
- case MESSAGE_BITFIELD:
- //Update the pieces list
- update_pieces_count_from_bitfield(peer, message->bitfield);
- //Store the bitfield
- remote_peer->bitfield = message->bitfield;
- xbt_assert(!remote_peer->am_interested, "Should not be interested at first");
- if (is_interested(peer, remote_peer)) {
- remote_peer->am_interested = 1;
- send_interested(peer, message->mailbox);
- }
- break;
- case MESSAGE_INTERESTED:
- xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
- //Update the interested state of the peer.
- remote_peer->interested = 1;
- update_active_peers_set(peer, remote_peer);
- break;
- case MESSAGE_NOTINTERESTED:
- xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
- remote_peer->interested = 0;
- update_active_peers_set(peer, remote_peer);
- break;
- case MESSAGE_UNCHOKE:
- xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
- xbt_assert(remote_peer->choked_download);
- remote_peer->choked_download = 0;
- //Send requests to the peer, since it has unchoked us
- if (remote_peer->am_interested)
- request_new_piece_to_peer(peer, remote_peer);
- break;
- case MESSAGE_CHOKE:
- xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
- xbt_assert(!remote_peer->choked_download);
- remote_peer->choked_download = 1;
- if (remote_peer->current_piece != -1)
- remove_current_piece(peer, remote_peer, remote_peer->current_piece);
- break;
- case MESSAGE_HAVE:
- XBT_DEBUG("\t for piece %d", message->index);
- xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
- remote_peer->bitfield = remote_peer->bitfield | (1U<<message->index);
- peer->pieces_count[message->index]++;
- //If the piece is in our pieces, we tell the peer that we are interested.
- if ((remote_peer->am_interested == 0) && peer_has_not_piece(peer,message->index)) {
- remote_peer->am_interested = 1;
- send_interested(peer, message->mailbox);
- if (remote_peer->choked_download == 0)
- request_new_piece_to_peer(peer, remote_peer);
- }
- break;
- case MESSAGE_REQUEST:
- xbt_assert(remote_peer->interested);
- xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
- if (remote_peer->choked_upload == 0) {
- XBT_DEBUG("\t for piece %d (%d,%d)", message->index, message->block_index,
- message->block_index + message->block_length);
- if (!peer_has_not_piece(peer, message->index)) {
- send_piece(peer, message->mailbox, message->index, message->block_index, message->block_length);
- }
- } else {
- XBT_DEBUG("\t for piece %d but he is choked.", message->peer_id);
- }
- break;
- case MESSAGE_PIECE:
- XBT_DEBUG(" \t for piece %d (%d,%d)", message->index, message->block_index,
- message->block_index + message->block_length);
- xbt_assert(!remote_peer->choked_download);
- xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
- "Can't received a piece if I'm not interested wihtout end-game mode!"
- "piece (%d) bitfield(%u) remote bitfield(%u)", message->index, peer->bitfield, remote_peer->bitfield);
- xbt_assert(remote_peer->choked_download != 1, "Can't received a piece if I'm choked !");
- xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
- //TODO: Execute à computation.
- if (peer_has_not_piece(peer,message->index)) {
- update_bitfield_blocks(peer, message->index, message->block_index, message->block_length);
- if (piece_complete(peer, message->index)) {
- //Removing the piece from our piece list
- remove_current_piece(peer, remote_peer, message->index);
- //Setting the fact that we have the piece
- peer->bitfield = peer->bitfield | (1U<<message->index);
- char* status = xbt_malloc0(FILE_PIECES+1);
- get_status(&status, peer->bitfield);
- XBT_DEBUG("My status is now %s", status);
- xbt_free(status);
- //Sending the information to all the peers we are connected to
- send_have(peer, message->index);
- //sending UNINTERESTED to peers that do not have what we want.
- update_interested_after_receive(peer);
- } else { // piece not completed
- send_request_to_peer(peer, remote_peer, message->index); // ask for the next block
- }
- } else {
- XBT_DEBUG("However, we already have it");
- xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
- request_new_piece_to_peer(peer, remote_peer);
- }
- break;
- case MESSAGE_CANCEL:
- break;
- default:
- THROW_IMPOSSIBLE;
- }
- //Update the peer speed.
- if (remote_peer) {
- connection_add_speed_value(remote_peer, 1.0 / (MSG_get_clock() - peer->begin_receive_time));
- }
- peer->begin_receive_time = MSG_get_clock();
-
- task_message_free(task);
-}
-
-/** Selects the appropriate piece to download and requests it to the remote_peer */
-void request_new_piece_to_peer(peer_t peer, connection_t remote_peer)
-{
- int piece = select_piece_to_download(peer, remote_peer);
- if (piece != -1) {
- peer->current_pieces|= (1U << (unsigned int) piece);
- send_request_to_peer(peer, remote_peer, piece);
- }
-}
-
-/** remove current_piece from the list of currently downloaded pieces. */
-void remove_current_piece(peer_t peer, connection_t remote_peer, unsigned int current_piece)
-{
- peer->current_pieces &= ~(1U << current_piece);
- remote_peer->current_piece = -1;
-}
-
-/** @brief Updates the list of who has a piece from a bitfield
- * @param peer peer we want to update the list
- * @param bitfield bitfield
- */
-void update_pieces_count_from_bitfield(peer_t peer, unsigned int bitfield)
-{
- for (int i = 0; i < FILE_PIECES; i++) {
- if (bitfield & (1U << i)) {
- peer->pieces_count[i]++;
- }
- }
-}
-
-/** @brief Return the piece to be downloaded
- * There are two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
- * If a piece is partially downloaded, this piece will be selected prioritarily
- * If the peer has strictly less than 4 pieces, he chooses a piece at random.
- * If the peer has more than pieces, he downloads the pieces that are the less replicated (rarest policy).
- * If all pieces have been downloaded or requested, we select a random requested piece (endgame mode).
- * @param peer: local peer
- * @param remote_peer: information about the connection
- * @return the piece to download if possible. -1 otherwise
- */
-int select_piece_to_download(peer_t peer, connection_t remote_peer)
-{
- int piece = partially_downloaded_piece(peer, remote_peer);
- // strict priority policy
- if (piece != -1)
- return piece;
-
- // end game mode
- if (count_pieces(peer->current_pieces) >= (FILE_PIECES - count_pieces(peer->bitfield)) &&
- (is_interested(peer, remote_peer) != 0)) {
-#if ENABLE_END_GAME_MODE == 0
- return -1;
-#endif
- int nb_interesting_pieces = 0;
- // compute the number of interesting pieces
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer,i) && connection_has_piece(remote_peer,i)) {
- nb_interesting_pieces++;
- }
- }
- xbt_assert(nb_interesting_pieces != 0);
- // get a random interesting piece
- int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
- int current_index = 0;
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer,i) && connection_has_piece(remote_peer,i)) {
- if (random_piece_index == current_index) {
- piece = i;
- break;
- }
- current_index++;
- }
- }
- xbt_assert(piece != -1);
- return piece;
- }
- // Random first policy
- if (count_pieces(peer->bitfield) < 4 && (is_interested_and_free(peer, remote_peer) != 0)) {
- int nb_interesting_pieces = 0;
- // compute the number of interesting pieces
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) && peer_is_not_downloading_piece(peer, i)) {
- nb_interesting_pieces++;
- }
- }
- xbt_assert(nb_interesting_pieces != 0);
- // get a random interesting piece
- int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
- int current_index = 0;
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) && peer_is_not_downloading_piece(peer, i)) {
- if (random_piece_index == current_index) {
- piece = i;
- break;
- }
- current_index++;
- }
- }
- xbt_assert(piece != -1);
- return piece;
- } else { // Rarest first policy
- short min = SHRT_MAX;
- int nb_min_pieces = 0;
- int current_index = 0;
- // compute the smallest number of copies of available pieces
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer->pieces_count[i] < min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) &&
- peer_is_not_downloading_piece(peer, i))
- min = peer->pieces_count[i];
- }
- xbt_assert(min != SHRT_MAX || (is_interested_and_free(peer, remote_peer) ==0));
- // compute the number of rarest pieces
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer->pieces_count[i] == min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) &&
- peer_is_not_downloading_piece(peer, i))
- nb_min_pieces++;
- }
- xbt_assert(nb_min_pieces != 0 || (is_interested_and_free(peer, remote_peer)==0));
- // get a random rarest piece
- int random_rarest_index = RngStream_RandInt(peer->stream, 0, nb_min_pieces - 1);
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer->pieces_count[i] == min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) &&
- peer_is_not_downloading_piece(peer, i)) {
- if (random_rarest_index == current_index) {
- piece = i;
- break;
- }
- current_index++;
- }
- }
- xbt_assert(piece != -1 || (is_interested_and_free(peer, remote_peer) == 0));
- return piece;
- }
-}
-
-/** @brief Update the list of current choked and unchoked peers, using the choke algorithm
- * @param peer the current peer
- */
-void update_choked_peers(peer_t peer)
-{
- if (nb_interested_peers(peer) == 0)
- return;
- XBT_DEBUG("(%d) update_choked peers %u active peers", peer->id, xbt_dict_size(peer->active_peers));
- //update the current round
- peer->round = (peer->round + 1) % 3;
- char *key;
- char *key_choked=NULL;
- connection_t peer_choosed = NULL;
- connection_t peer_choked = NULL;
- //remove a peer from the list
- xbt_dict_cursor_t cursor = NULL;
- xbt_dict_cursor_first(peer->active_peers, &cursor);
- if (xbt_dict_length(peer->active_peers) > 0) {
- key_choked = xbt_dict_cursor_get_key(cursor);
- peer_choked = xbt_dict_cursor_get_data(cursor);
- }
- xbt_dict_cursor_free(&cursor);
-
- /**If we are currently seeding, we unchoke the peer which has been unchoked the last time.*/
- if (has_finished(peer->bitfield)) {
- connection_t connection;
- double unchoke_time = MSG_get_clock() + 1;
-
- xbt_dict_foreach(peer->peers, cursor, key, connection) {
- if (connection->last_unchoke < unchoke_time &&
- (connection->interested != 0) && (connection->choked_upload != 0)) {
- unchoke_time = connection->last_unchoke;
- peer_choosed = connection;
- }
- }
- } else {
- //Random optimistic unchoking
- if (peer->round == 0) {
- int j = 0;
- do {
- //We choose a random peer to unchoke.
- int id_chosen = RngStream_RandInt(peer->stream, 0, xbt_dict_length(peer->peers) - 1);
- int i = 0;
- connection_t connection;
- xbt_dict_foreach(peer->peers, cursor, key, connection) {
- if (i == id_chosen) {
- peer_choosed = connection;
- break;
- }
- i++;
- }
- xbt_dict_cursor_free(&cursor);
- if (peer_choosed == NULL)
- THROWF(unknown_error, 0, "A peer should have be selected at this point");
- else if ((peer_choosed->interested == 0) || (peer_choosed->choked_upload == 0))
- peer_choosed = NULL;
- else
- XBT_DEBUG("Nothing to do, keep going");
- j++;
- } while (peer_choosed == NULL && j < MAXIMUM_PEERS);
- } else {
- //Use the "fastest download" policy.
- connection_t connection;
- double fastest_speed = 0.0;
- xbt_dict_foreach(peer->peers, cursor, key, connection) {
- if (connection->peer_speed > fastest_speed &&
- (connection->choked_upload != 0) && (connection->interested != 0)) {
- peer_choosed = connection;
- fastest_speed = connection->peer_speed;
- }
- }
- }
- }
-
- if (peer_choosed != NULL)
- XBT_DEBUG("(%d) update_choked peers unchoked (%d) ; int (%d) ; choked (%d) ",
- peer->id, peer_choosed->id, peer_choosed->interested, peer_choosed->choked_upload);
-
- if (peer_choked != peer_choosed) {
- if (peer_choked != NULL) {
- xbt_assert((!peer_choked->choked_upload), "Tries to choked a choked peer");
- peer_choked->choked_upload = 1;
- xbt_assert((*((int *) key_choked) == peer_choked->id));
- update_active_peers_set(peer, peer_choked);
- XBT_DEBUG("(%d) Sending a CHOKE to %d", peer->id, peer_choked->id);
- send_choked(peer, peer_choked->mailbox);
- }
- if (peer_choosed != NULL) {
- xbt_assert((peer_choosed->choked_upload), "Tries to unchoked an unchoked peer");
- peer_choosed->choked_upload = 0;
- xbt_dict_set_ext(peer->active_peers, (char *) &peer_choosed->id, sizeof(int), peer_choosed, NULL);
- peer_choosed->last_unchoke = MSG_get_clock();
- XBT_DEBUG("(%d) Sending a UNCHOKE to %d", peer->id, peer_choosed->id);
- update_active_peers_set(peer, peer_choosed);
- send_unchoked(peer, peer_choosed->mailbox);
- }
- }
-}
-
-/** @brief Update "interested" state of peers: send "not interested" to peers that don't have any more pieces we want.
- * @param peer our peer data
- */
-void update_interested_after_receive(peer_t peer)
-{
- char *key;
- xbt_dict_cursor_t cursor;
- connection_t connection;
- xbt_dict_foreach(peer->peers, cursor, key, connection) {
- if (connection->am_interested != 0) {
- int interested = 0;
- //Check if the peer still has a piece we want.
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer, i) && connection_has_piece(connection,i)) {
- interested = 1;
- break;
- }
- }
- if (!interested) { //no more piece to download from connection
- connection->am_interested = 0;
- send_notinterested(peer, connection->mailbox);
- }
- }
- }
-}
-
-void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length)
-{
- xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
- xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.", block_index);
- for (int i = block_index; i < (block_index + block_length); i++) {
- peer->bitfield_blocks |= (1ULL<<(unsigned int)(index * PIECES_BLOCKS + i));
- }
-}
-
-/** Returns if a peer has completed the download of a piece */
-int piece_complete(peer_t peer, int index)
-{
- for (int i = 0; i < PIECES_BLOCKS; i++) {
- if (!(peer->bitfield_blocks & 1ULL<<(index * PIECES_BLOCKS + i))) {
- return 0;
- }
- }
- return 1;
-}
-
-/** Returns the first block that a peer doesn't have in a piece. If the peer has all blocks of the piece, returns -1. */
-int get_first_block(peer_t peer, int piece)
-{
- for (int i = 0; i < PIECES_BLOCKS; i++) {
- if (!(peer->bitfield_blocks & 1ULL<<(piece * PIECES_BLOCKS + i))) {
- return i;
- }
- }
- return -1;
-}
-
-/** Indicates if the remote peer has a piece not stored by the local peer */
-int is_interested(peer_t peer, connection_t remote_peer)
-{
- return remote_peer->bitfield & (peer->bitfield^((1<<FILE_PIECES)-1));
-}
-
-/** Indicates if the remote peer has a piece not stored by the local peer nor requested by the local peer */
-int is_interested_and_free(peer_t peer, connection_t remote_peer)
-{
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) && peer_is_not_downloading_piece(peer, i)) {
- return 1;
- }
- }
- return 0;
-}
-
-/** Returns a piece that is partially downloaded and stored by the remote peer if any -1 otherwise. */
-int partially_downloaded_piece(peer_t peer, connection_t remote_peer)
-{
- for (int i = 0; i < FILE_PIECES; i++) {
- if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) && peer_is_not_downloading_piece(peer, i) &&
- get_first_block(peer, i) > 0)
- return i;
- }
- return -1;
-}
-
-/** @brief Send request messages to a peer that have unchoked us
- * @param peer peer
- * @param remote_peer peer data to the peer we want to send the request
- */
-void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece)
-{
- remote_peer->current_piece = piece;
- xbt_assert(connection_has_piece(remote_peer,piece));
- int block_index = get_first_block(peer, piece);
- if (block_index != -1) {
- int block_length = MIN(BLOCKS_REQUESTED, PIECES_BLOCKS - block_index);
- send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
- }
-}
-
-/***********************************************************
- *
- * Low level message functions
- *
- ***********************************************************/
-
-/** @brief Send a "interested" message to a peer
- * @param peer peer data
- * @param mailbox destination mailbox
- */
-void send_interested(peer_t peer, const char *mailbox)
-{
- msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id,
- task_message_size(MESSAGE_INTERESTED));
- MSG_task_dsend(task, mailbox, task_message_free);
- XBT_DEBUG("Sending INTERESTED to %s", mailbox);
-}
-
-/** @brief Send a "not interested" message to a peer
- * @param peer peer data
- * @param mailbox destination mailbox
- */
-void send_notinterested(peer_t peer, const char *mailbox)
-{
- msg_task_t task = task_message_new(MESSAGE_NOTINTERESTED, peer->hostname, peer->mailbox, peer->id,
- task_message_size(MESSAGE_NOTINTERESTED));
- MSG_task_dsend(task, mailbox, task_message_free);
- XBT_DEBUG("Sending NOTINTERESTED to %s", mailbox);
-}
-
-/** @brief Send a handshake message to all the peers the peer has.
- * @param peer peer data
- */
-void send_handshake_all(peer_t peer)
-{
- connection_t remote_peer;
- xbt_dict_cursor_t cursor = NULL;
- char *key;
- xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
- msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
- task_message_size(MESSAGE_HANDSHAKE));
- MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
- XBT_DEBUG("Sending a HANDSHAKE to %s", remote_peer->mailbox);
- }
-}
-
-/** @brief Send a "handshake" message to an user
- * @param peer peer data
- * @param mailbox mailbox where to we send the message
- */
-void send_handshake(peer_t peer, const char *mailbox)
-{
- XBT_DEBUG("Sending a HANDSHAKE to %s", mailbox);
- msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
- task_message_size(MESSAGE_HANDSHAKE));
- MSG_task_dsend(task, mailbox, task_message_free);
-}
-
-/** Send a "choked" message to a peer. */
-void send_choked(peer_t peer, const char *mailbox)
-{
- XBT_DEBUG("Sending a CHOKE to %s", mailbox);
- msg_task_t task = task_message_new(MESSAGE_CHOKE, peer->hostname, peer->mailbox, peer->id,
- task_message_size(MESSAGE_CHOKE));
- MSG_task_dsend(task, mailbox, task_message_free);
-}
-
-/** Send a "unchoked" message to a peer */
-void send_unchoked(peer_t peer, const char *mailbox)
-{
- XBT_DEBUG("Sending a UNCHOKE to %s", mailbox);
- msg_task_t task = task_message_new(MESSAGE_UNCHOKE, peer->hostname, peer->mailbox, peer->id,
- task_message_size(MESSAGE_UNCHOKE));
- MSG_task_dsend(task, mailbox, task_message_free);
-}
-
-/** Send a "HAVE" message to all peers we are connected to */
-void send_have(peer_t peer, int piece)
-{
- XBT_DEBUG("Sending HAVE message to all my peers");
- connection_t remote_peer;
- xbt_dict_cursor_t cursor = NULL;
- char *key;
- xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
- msg_task_t task = task_message_index_new(MESSAGE_HAVE, peer->hostname, peer->mailbox, peer->id, piece,
- task_message_size(MESSAGE_HAVE));
- MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
- }
-}
-
-/** @brief Send a bitfield message to all the peers the peer has.
- * @param peer peer data
- */
-void send_bitfield(peer_t peer, const char *mailbox)
-{
- XBT_DEBUG("Sending a BITFIELD to %s", mailbox);
- msg_task_t task = task_message_bitfield_new(peer->hostname, peer->mailbox, peer->id, peer->bitfield, FILE_PIECES);
- MSG_task_dsend(task, mailbox, task_message_free);
-}
-
-/** Send a "request" message to a pair, containing a request for a piece */
-void send_request(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
-{
- XBT_DEBUG("Sending a REQUEST to %s for piece %d (%d,%d)", mailbox, piece, block_index, block_length);
- msg_task_t task = task_message_request_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length);
- MSG_task_dsend(task, mailbox, task_message_free);
-}
-
-/** Send a "piece" message to a pair, containing a piece of the file */
-void send_piece(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
-{
- XBT_DEBUG("Sending the PIECE %d (%d,%d) to %s", piece, block_index, block_length, mailbox);
- xbt_assert(piece >= 0, "Tried to send a piece that doesn't exist.");
- xbt_assert(!peer_has_not_piece(peer,piece), "Tried to send a piece that we doesn't have.");
- msg_task_t task = task_message_piece_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length,
- BLOCK_SIZE);
- MSG_task_dsend(task, mailbox, task_message_free);
-}
