--- /dev/null
+ /* Copyright (c) 2012. 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 <msg/msg.h>
+#include <xbt/RngStream.h>
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(msg_peers,
+ "Messages specific for the peers");
+
+
+
+/**
+ * Peer main function
+ */
+int peer(int argc, char *argv[]) {
+ s_peer_t peer;
+ //Check arguments
+ xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
+ //Build peer object
+ if (argc == 4) {
+ peer_init(&peer, atoi(argv[1]),1);
+ }
+ else {
+ peer_init(&peer, atoi(argv[1]),0);
+ }
+ //Retrieve deadline
+ double deadline = atof(argv[2]);
+ xbt_assert(deadline > 0, "Wrong deadline supplied");
+ 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", xbt_dict_length(peer.peers));
+ XBT_DEBUG("Here is my current status: %s",peer.bitfield);
+ peer.begin_receive_time = MSG_get_clock();
+ if (has_finished(peer.bitfield)) {
+ peer.pieces = FILE_PIECES;
+ send_handshake_all(&peer);
+ seed_loop(&peer,deadline);
+ }
+ else {
+ leech_loop(&peer,deadline);
+ seed_loop(&peer,deadline);
+ }
+ }
+ else {
+ XBT_INFO("Couldn't contact the tracker.");
+ }
+
+ XBT_INFO("Here is my current status: %s", peer.bitfield);
+ if (peer.comm_received) {
+ MSG_comm_destroy(peer.comm_received);
+ }
+
+ peer_free(&peer);
+ return 0;
+}
+/**
+ * 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);
+ //Wait for at least one "bitfield" message.
+ wait_for_pieces(peer,deadline);
+ XBT_DEBUG("Starting main leech loop");
+ while (MSG_get_clock() < deadline && peer->pieces < 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 {
+ if (peer->current_piece != -1) {
+ send_interested_to_peers(peer);
+ }
+ else {
+ //If the current interested pieces is < MAX
+ if (peer->pieces_requested < MAX_PIECES) {
+ update_current_piece(peer);
+ }
+ }
+ //We don't execute the choke algorithm if we don't already have a piece
+ if (MSG_get_clock() >= next_choked_update && peer->pieces > 0) {
+ update_choked_peers(peer);
+ next_choked_update += UPDATE_CHOKED_INTERVAL;
+ }
+ else {
+ MSG_process_sleep(1);
+ }
+ }
+ }
+}
+/**
+ * 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(1);
+ }
+ }
+ }
+}
+/**
+ * Retrieves the peer list from the tracker
+ * @param peer current peer data
+ */
+int get_peers_data(peer_t peer) {
+ int success = 0, send_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);
+ //Build the task to send.
+ msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
+ msg_task_t task_received = NULL;
+ msg_comm_t comm_received;
+ while (!send_success && 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) {
+ send_success = 1;
+ }
+ }
+ while (!success && MSG_get_clock() < timeout) {
+ 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);
+ int i, 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);
+ comm_received = NULL;
+ }
+ }
+
+ return success;
+}
+/**
+ * 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.
+ */
+void peer_init(peer_t peer, int id, int seed) {
+ peer->id = id;
+ sprintf(peer->mailbox,"%d",id);
+ sprintf(peer->mailbox_tracker,"tracker_%d",id);
+ peer->peers = xbt_dict_new();
+ peer->active_peers = xbt_dict_new();
+ peer->hostname = MSG_host_get_name(MSG_host_self());
+
+ peer->bitfield = xbt_new(char,FILE_PIECES + 1);
+ peer->bitfield_blocks = xbt_new(char,(FILE_PIECES) * (PIECES_BLOCKS) + 1);
+ if (seed) {
+ memset(peer->bitfield,'1',sizeof(char) * (FILE_PIECES + 1));
+ memset(peer->bitfield_blocks,'1',sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
+ }
+ else {
+ memset(peer->bitfield,'0',sizeof(char) * (FILE_PIECES + 1));
+ memset(peer->bitfield_blocks,'0',sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
+ }
+
+ peer->bitfield[FILE_PIECES] = '\0';
+ peer->pieces = 0;
+
+ peer->pieces_count = xbt_new0(short,FILE_PIECES);
+ peer->pieces_requested = 0;
+
+ peer->current_pieces = xbt_dynar_new(sizeof(int),NULL);
+ peer->current_piece = -1;
+
+ peer->stream = RngStream_CreateStream("");
+ peer->comm_received = NULL;
+
+ peer->round = 0;
+}
+/**
+ * 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_dynar_free(&peer->current_pieces);
+ xbt_free(peer->pieces_count);
+ xbt_free(peer->bitfield);
+ xbt_free(peer->bitfield_blocks);
+
+ RngStream_DeleteStream(&peer->stream);
+}
+/**
+ * Returns if a peer has finished downloading the file
+ * @param bitfield peer bitfield
+ */
+int has_finished(char *bitfield) {
+ return ((memchr(bitfield,'0',sizeof(char) * FILE_PIECES) == NULL) ? 1 : 0);
+}
+/**
+ * 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) {
+ message_t message = MSG_task_get_data(task);
+ 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:
+ XBT_DEBUG("Received a HANDSHAKE from %s (%s)",message->mailbox, message->issuer_host_name);
+ //Check if the peer is in our connection list.
+ if (!remote_peer) {
+ 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:
+ XBT_DEBUG("Recieved a BITFIELD message from %s (%s)",message->mailbox,message->issuer_host_name);
+ //Update the pieces list
+ update_pieces_count_from_bitfield(peer,message->bitfield);
+ //Store the bitfield
+ remote_peer->bitfield = xbt_strdup(message->bitfield);
+ //Update the current piece
+ if (peer->current_piece == -1 && peer->pieces < FILE_PIECES) {
+ update_current_piece(peer);
+ }
+ break;
+ case MESSAGE_INTERESTED:
+ XBT_DEBUG("Recieved an INTERESTED message from %s (%s)",message->mailbox,message->issuer_host_name);
+ 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;
+ break;
+ case MESSAGE_NOTINTERESTED:
+ XBT_DEBUG("Received a NOTINTERESTED message from %s (%s)", message->mailbox, message->issuer_host_name);
+ xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
+ remote_peer->interested = 0;
+ break;
+ case MESSAGE_UNCHOKE:
+ xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
+ XBT_DEBUG("Received a UNCHOKE message from %s (%s)",message->mailbox,message->issuer_host_name);
+ remote_peer->choked_download = 0;
+ xbt_dict_set_ext(peer->active_peers,(char*)&message->peer_id,sizeof(int),remote_peer,NULL);
+ //Send requests to the peer, since it has unchoked us
+ send_requests_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_DEBUG("Received a CHOKE message from %s (%s)",message->mailbox,message->issuer_host_name);
+ remote_peer->choked_download = 1;
+ xbt_ex_t e;
+ TRY {
+ xbt_dict_remove_ext(peer->active_peers,(char*)&message->peer_id,sizeof(int));
+ }
+ CATCH(e) {
+ xbt_ex_free(e);
+ }
+ break;
+ case MESSAGE_HAVE:
+ XBT_DEBUG("Received a HAVE message from %s (%s) of piece %d",message->mailbox, message->issuer_host_name, message->index);
+ xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
+ if (remote_peer->bitfield == NULL)
+ return;
+ remote_peer->bitfield[message->index] = '1';
+ 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 && in_current_pieces(peer, message->index)) {
+ remote_peer->am_interested = 1;
+ send_interested(peer,remote_peer->mailbox);
+ }
+ break;
+ case MESSAGE_REQUEST:
+ xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
+ if (!remote_peer->choked_upload) {
+ XBT_DEBUG("Received a REQUEST from %s (%s) for %d (%d,%d)",message->mailbox,message->issuer_host_name,message->peer_id, message->block_index,message->block_index + message->block_length);
+ if (peer->bitfield[message->index] == '1') {
+ send_piece(peer, message->mailbox, message->index, 0, message->block_index, message->block_length);
+ }
+ }
+ else {
+ XBT_DEBUG("Received a REQUEST from %s (%s) for %d but he is choked.",message->mailbox,message->issuer_host_name,message->peer_id);
+ }
+ break;
+ case MESSAGE_PIECE:
+ xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
+ //TODO: Execute à computation.
+ if (message->stalled) {
+ XBT_DEBUG("The received piece %d from %s (%s) is STALLED",message->index, message->mailbox, message->issuer_host_name);
+ }
+ else {
+ XBT_DEBUG("Received piece %d (%d,%d) from %s (%s)",message->index, message->block_index, message->block_index + message->block_length, message->mailbox, message->issuer_host_name);
+ if (peer->bitfield[message->index] == '0') {
+ update_bitfield_blocks(peer,message->index,message->block_index,message->block_length);
+ if (piece_complete(peer,message->index)) {
+ peer->pieces_requested--;
+ //Removing the piece from our piece list
+ int piece_index = -1, i, piece;
+ xbt_dynar_foreach(peer->current_pieces, i, piece) {
+ if (piece == message->index) {
+ piece_index = i;
+ break;
+ }
+ }
+ xbt_assert(piece_index != -1, "Received an incorrect piece");
+ xbt_dynar_remove_at(peer->current_pieces,piece_index,NULL);
+ //Setting the fact that we have the piece
+ peer->bitfield[message->index] = '1';
+ peer->pieces++;
+ XBT_DEBUG("My status is now %s",peer->bitfield);
+ //Sending the information to all the peers we are connected to
+ send_have(peer,message->index);
+ //sending UNINTERSTED to peers that doesn't have what we want.
+ update_interested_after_receive(peer);
+ }
+ }
+ else {
+ XBT_DEBUG("However, we already have it");
+ }
+ }
+ break;
+ }
+ //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);
+}
+
+/**
+ * Wait for the node to receive interesting bitfield messages (ie: non empty)
+ * to be received
+ * @param deadline peer deadline
+ * @param peer peer data
+ */
+void wait_for_pieces(peer_t peer, double deadline) {
+ int finished = 0;
+ while (MSG_get_clock() < deadline && !finished) {
+ if (peer->comm_received == NULL) {
+ peer->task_received = NULL;
+ peer->comm_received = MSG_task_irecv(&peer->task_received,peer->mailbox);
+ }
+ msg_error_t status = MSG_comm_wait(peer->comm_received,TIMEOUT_MESSAGE);
+ //free the comm already, we don't need it anymore
+ MSG_comm_destroy(peer->comm_received);
+ peer->comm_received = NULL;
+ if (status == MSG_OK) {
+ message_t message = MSG_task_get_data(peer->task_received);
+ handle_message(peer,peer->task_received);
+ if (peer->current_piece != -1) {
+ finished = 1;
+ }
+ }
+ }
+}
+/**
+ * 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, char *bitfield) {
+ int i;
+ for (i = 0; i < FILE_PIECES; i++) {
+ if (bitfield[i] == '1') {
+ peer->pieces_count[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
+ */
+void update_current_piece(peer_t peer) {
+ if (xbt_dynar_length(peer->current_pieces) >= (FILE_PIECES - peer->pieces)) {
+ return;
+ }
+ if (1 || peer->pieces < 3) {
+ int i = 0 ;
+ do {
+ peer->current_piece = RngStream_RandInt(peer->stream,0,FILE_PIECES - 1);;
+ i++;
+ } while (!(peer->bitfield[peer->current_piece] == '0' && !in_current_pieces(peer,peer->current_piece)));
+ }
+ else {
+ //Trivial min algorithm.
+ int i, min_id = -1;
+ short min = -1;
+ for (i = 0; i < FILE_PIECES; i++) {
+ if (peer->bitfield[i] == '0') {
+ min = peer->pieces_count[i];
+ min_id = i;
+ break;
+ }
+ }
+ xbt_assert((min > -1), "Couldn't find a minimum");
+ for (i = 1; i < FILE_PIECES; i++) {
+ if (peer->pieces_count[i] < min && peer->bitfield[i] == '0') {
+ min = peer->pieces_count[i];
+ min_id = i;
+ }
+ }
+ peer->current_piece = min_id;
+ }
+ xbt_dynar_push_as(peer->current_pieces, int, peer->current_piece);
+ XBT_DEBUG("New interested piece: %d",peer->current_piece);
+ xbt_assert((peer->current_piece >= 0 && peer->current_piece < FILE_PIECES, "Peer want to retrieve a piece that doesn't exist."));
+}
+/**
+ * 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) {
+ //update the current round
+ peer->round = (peer->round + 1) % 3;
+ int i;
+ char *key;
+ connection_t peer_choosed = 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 = xbt_dict_cursor_get_key(cursor);
+ connection_t peer_choked = xbt_dict_cursor_get_data(cursor);
+ if (peer_choked) {
+ send_choked(peer,peer_choked->mailbox);
+ peer_choked->choked_upload = 1;
+ }
+ xbt_dict_remove_ext(peer->active_peers,key,sizeof(int));
+ }
+ xbt_dict_cursor_free(&cursor);
+
+ /**
+ * If we are currently seeding, we unchoke the peer which has
+ * been unchoke the least time.
+ */
+ if (peer->pieces == FILE_PIECES) {
+ 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) {
+ 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->interested == 0) {
+ peer_choosed = NULL;
+ }
+ j++;
+ } while (peer_choosed == NULL && j < MAXIMUM_PAIRS);
+ }
+ 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 && connection->interested) {
+ peer_choosed = connection;
+ fastest_speed = connection->peer_speed;
+ }
+ }
+ }
+
+ }
+ if (peer_choosed != NULL) {
+ 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();
+ send_unchoked(peer,peer_choosed->mailbox);
+ }
+
+}
+/**
+ * Updates our "interested" state about 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;
+ int interested, cpt, piece;
+ xbt_dict_foreach(peer->peers, cursor, key, connection) {
+ interested = 0;
+ if (connection->am_interested) {
+ //Check if the peer still has a piece we want.
+ xbt_dynar_foreach(peer->current_pieces, cpt, piece) {
+ xbt_assert((piece >= 0), "Wrong piece.");
+ if (connection->bitfield && connection->bitfield[piece] == '1') {
+ interested = 1;
+ break;
+ }
+ }
+ if (!interested) {
+ connection->am_interested = 0;
+ send_notinterested(peer,connection->mailbox);
+ }
+ }
+ }
+}
+void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length) {
+ int i;
+ xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
+ xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.",block_index);
+ for (i = block_index; i < (block_index + block_length); i++) {
+ peer->bitfield_blocks[index * PIECES_BLOCKS + i] = '1';
+ }
+}
+/**
+ * Returns if a peer has completed the download of a piece
+ */
+int piece_complete(peer_t peer, int index) {
+ int i;
+ for (i = 0; i < PIECES_BLOCKS; i++) {
+ if (peer->bitfield_blocks[index * PIECES_BLOCKS + i] == '0') {
+ return 0;
+ }
+ }
+ return 1;
+}
+/**
+ * Returns the first block that a peer doesn't have in a piece
+ */
+int get_first_block(peer_t peer, int piece) {
+ int i;
+ for (i = 0; i < PIECES_BLOCKS; i++) {
+ if (peer->bitfield_blocks[piece * PIECES_BLOCKS + i] == '0') {
+ return i;
+ }
+ }
+ return -1;
+}
+/**
+ * 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_requests_to_peer(peer_t peer, connection_t remote_peer) {
+ int i, piece, block_index, block_length;
+ xbt_dynar_foreach(peer->current_pieces, i, piece) {
+ if (remote_peer->bitfield && remote_peer->bitfield[piece] == '1') {
+ block_index = get_first_block(peer,piece);
+ if (block_index != -1) {
+ block_length = PIECES_BLOCKS - block_index;
+ block_length = min(BLOCKS_REQUESTED,block_length);
+ send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
+ break;
+ }
+ }
+ }
+}
+/**
+ * Find the peers that have the current interested piece and send them
+ * the "interested" message
+ */
+void send_interested_to_peers(peer_t peer) {
+ char *key;
+ xbt_dict_cursor_t cursor=NULL;
+ connection_t connection;
+ xbt_assert((peer->current_piece != -1), "Tried to send a interested message wheras the current_piece is -1");
+ xbt_dict_foreach(peer->peers, cursor, key, connection) {
+ if (connection->bitfield && connection->bitfield[peer->current_piece] == '1') {
+ connection->am_interested = 1;
+ msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id);
+ MSG_task_dsend(task,connection->mailbox,task_message_free);
+ XBT_DEBUG("Send INTERESTED to %s",connection->mailbox);
+ }
+ }
+ peer->current_piece = -1;
+ peer->pieces_requested++;
+}
+/**
+ * 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);
+ MSG_task_dsend(task,mailbox,task_message_free);
+ XBT_DEBUG("Sending INTERESTED to %s",mailbox);
+
+}
+/**
+ * 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);
+ MSG_task_dsend(task,mailbox,task_message_free);
+ XBT_DEBUG("Sending NOTINTERESTED to %s",mailbox);
+
+}
+/**
+ * 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);
+ MSG_task_dsend(task,remote_peer->mailbox,task_message_free);
+ XBT_DEBUG("Sending a HANDSHAKE to %s",remote_peer->mailbox);
+ }
+}
+/**
+ * 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) {
+ msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox,peer->id);
+ MSG_task_dsend(task,mailbox,task_message_free);
+ XBT_DEBUG("Sending a HANDSHAKE to %s",mailbox);
+}
+/**
+ * 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);
+ 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);
+ 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);
+ MSG_task_dsend(task,remote_peer->mailbox,task_message_free);
+ }
+}
+/**
+ * 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);
+ 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 stalled, 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->bitfield[piece] == '1'), "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, stalled, block_index, block_length);
+ MSG_task_dsend(task,mailbox,task_message_free);
+}
+
+int in_current_pieces(peer_t peer, int piece) {
+ int is_in = 0, i, peer_piece;
+ xbt_dynar_foreach(peer->current_pieces,i, peer_piece) {
+ if (peer_piece == piece) {
+ is_in = 1;
+ break;
+ }
+ }
+ return is_in;
+}
