1 /* Copyright (c) 2012-2017. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
8 #include "connection.h"
10 #include <simgrid/msg.h>
11 #include <xbt/RngStream.h>
14 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_peers, "Messages specific for the peers");
17 * User parameters for transferred file data. For the test, the default values are :
18 * File size: 10 pieces * 5 blocks/piece * 16384 bytes/block = 819200 bytes
20 #define FILE_PIECES 10
21 #define PIECES_BLOCKS 5
22 #define BLOCK_SIZE 16384
23 static const unsigned long int FILE_SIZE = FILE_PIECES * PIECES_BLOCKS * BLOCK_SIZE;
25 /** Number of blocks asked by each request */
26 #define BLOCKS_REQUESTED 2
28 #define ENABLE_END_GAME_MODE 1
29 #define SLEEP_DURATION 1
31 /** Peer main function */
32 int peer(int argc, char *argv[])
36 xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
39 peer_init(&peer, xbt_str_parse_int(argv[1],"Invalid ID: %s"), 1);
41 peer_init(&peer, xbt_str_parse_int(argv[1],"Invalid ID: %s"), 0);
44 double deadline = xbt_str_parse_double(argv[2],"Invalid deadline: %s");
45 xbt_assert(deadline > 0, "Wrong deadline supplied");
47 XBT_INFO("Hi, I'm joining the network with id %d", peer.id);
48 //Getting peer data from the tracker.
49 if (get_peers_data(&peer)) {
50 XBT_DEBUG("Got %d peers from the tracker. Current status is: %s", xbt_dict_length(peer.peers), peer.bitfield);
51 peer.begin_receive_time = MSG_get_clock();
52 MSG_mailbox_set_async(peer.mailbox);
53 if (has_finished(peer.bitfield)) {
54 peer.pieces = FILE_PIECES;
55 send_handshake_all(&peer);
56 seed_loop(&peer, deadline);
58 leech_loop(&peer, deadline);
59 seed_loop(&peer, deadline);
62 XBT_INFO("Couldn't contact the tracker.");
65 XBT_INFO("Here is my current status: %s", peer.bitfield);
66 if (peer.comm_received) {
67 MSG_comm_destroy(peer.comm_received);
74 /** @brief Peer main loop when it is leeching.
75 * @param peer peer data
76 * @param deadline time at which the peer has to leave
78 void leech_loop(peer_t peer, double deadline)
80 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
81 XBT_DEBUG("Start downloading.");
83 /* Send a "handshake" message to all the peers it got (since it couldn't have gotten more than 50 peers) */
84 send_handshake_all(peer);
85 XBT_DEBUG("Starting main leech loop");
87 while (MSG_get_clock() < deadline && peer->pieces < FILE_PIECES) {
88 if (peer->comm_received == NULL) {
89 peer->task_received = NULL;
90 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
92 if (MSG_comm_test(peer->comm_received)) {
93 msg_error_t status = MSG_comm_get_status(peer->comm_received);
94 MSG_comm_destroy(peer->comm_received);
95 peer->comm_received = NULL;
96 if (status == MSG_OK) {
97 handle_message(peer, peer->task_received);
100 //We don't execute the choke algorithm if we don't already have a piece
101 if (MSG_get_clock() >= next_choked_update && peer->pieces > 0) {
102 update_choked_peers(peer);
103 next_choked_update += UPDATE_CHOKED_INTERVAL;
105 MSG_process_sleep(SLEEP_DURATION);
109 if (peer->pieces == FILE_PIECES)
110 XBT_DEBUG("%d becomes a seeder", peer->id);
113 /** @brief Peer main loop when it is seeding
114 * @param peer peer data
115 * @param deadline time when the peer will leave
117 void seed_loop(peer_t peer, double deadline)
119 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
120 XBT_DEBUG("Start seeding.");
121 //start the main seed loop
122 while (MSG_get_clock() < deadline) {
123 if (peer->comm_received == NULL) {
124 peer->task_received = NULL;
125 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
127 if (MSG_comm_test(peer->comm_received)) {
128 msg_error_t status = MSG_comm_get_status(peer->comm_received);
129 MSG_comm_destroy(peer->comm_received);
130 peer->comm_received = NULL;
131 if (status == MSG_OK) {
132 handle_message(peer, peer->task_received);
135 if (MSG_get_clock() >= next_choked_update) {
136 update_choked_peers(peer);
137 //TODO: Change the choked peer algorithm when seeding.
138 next_choked_update += UPDATE_CHOKED_INTERVAL;
140 MSG_process_sleep(SLEEP_DURATION);
146 /** @brief Retrieves the peer list from the tracker
147 * @param peer current peer data
149 int get_peers_data(peer_t peer)
152 double timeout = MSG_get_clock() + GET_PEERS_TIMEOUT;
154 //Build the task to send to the tracker
155 tracker_task_data_t data = tracker_task_data_new(MSG_host_get_name(MSG_host_self()), peer->mailbox_tracker,
156 peer->id, 0, 0, FILE_SIZE);
157 msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
158 while ((success == 0) && MSG_get_clock() < timeout) {
159 XBT_DEBUG("Sending a peer request to the tracker.");
160 msg_error_t status = MSG_task_send_with_timeout(task_send, TRACKER_MAILBOX, GET_PEERS_TIMEOUT);
161 if (status == MSG_OK) {
167 msg_task_t task_received = NULL;
168 while ((success == 0) && MSG_get_clock() < timeout) {
169 msg_comm_t comm_received = MSG_task_irecv(&task_received, peer->mailbox_tracker);
170 msg_error_t status = MSG_comm_wait(comm_received, GET_PEERS_TIMEOUT);
171 if (status == MSG_OK) {
172 tracker_task_data_t data = MSG_task_get_data(task_received);
175 //Add the peers the tracker gave us to our peer list.
176 xbt_dynar_foreach(data->peers, i, peer_id) {
177 if (peer_id != peer->id)
178 xbt_dict_set_ext(peer->peers, (char *) &peer_id, sizeof(int), connection_new(peer_id), NULL);
181 //free the communication and the task
182 MSG_comm_destroy(comm_received);
183 tracker_task_data_free(data);
184 MSG_task_destroy(task_received);
191 /** @brief Initialize the peer data.
192 * @param peer peer data
193 * @param id id of the peer to take in the network
194 * @param seed indicates if the peer is a seed.
196 void peer_init(peer_t peer, int id, int seed)
199 snprintf(peer->mailbox,MAILBOX_SIZE-1, "%d", id);
200 snprintf(peer->mailbox_tracker,MAILBOX_SIZE-1, "tracker_%d", id);
201 peer->peers = xbt_dict_new_homogeneous(NULL);
202 peer->active_peers = xbt_dict_new_homogeneous(NULL);
203 peer->hostname = MSG_host_get_name(MSG_host_self());
205 peer->bitfield = xbt_new(char, FILE_PIECES + 1);
206 peer->bitfield_blocks = xbt_new(char, (FILE_PIECES) * (PIECES_BLOCKS) + 1);
208 memset(peer->bitfield, '1', sizeof(char) * (FILE_PIECES + 1));
209 memset(peer->bitfield_blocks, '1', sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
211 memset(peer->bitfield, '0', sizeof(char) * (FILE_PIECES + 1));
212 memset(peer->bitfield_blocks, '0', sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
215 peer->bitfield[FILE_PIECES] = '\0';
218 peer->pieces_count = xbt_new0(short, FILE_PIECES);
220 peer->current_pieces = xbt_dynar_new(sizeof(int), NULL);
222 peer->stream = (RngStream)MSG_host_get_data(MSG_host_self());
223 peer->comm_received = NULL;
228 /** Destroys a poor peer object. */
229 void peer_free(peer_t peer)
232 connection_t connection;
233 xbt_dict_cursor_t cursor;
234 xbt_dict_foreach(peer->peers, cursor, key, connection) {
235 connection_free(connection);
237 xbt_dict_free(&peer->peers);
238 xbt_dict_free(&peer->active_peers);
239 xbt_dynar_free(&peer->current_pieces);
240 xbt_free(peer->pieces_count);
241 xbt_free(peer->bitfield);
242 xbt_free(peer->bitfield_blocks);
245 /** @brief Returns if a peer has finished downloading the file
246 * @param bitfield peer bitfield
248 int has_finished(char *bitfield)
250 return ((memchr(bitfield, '0', sizeof(char) * FILE_PIECES) == NULL) ? 1 : 0);
253 int nb_interested_peers(peer_t peer)
255 xbt_dict_cursor_t cursor = NULL;
257 connection_t connection;
259 xbt_dict_foreach(peer->peers, cursor, key, connection) {
260 if (connection->interested)
266 void update_active_peers_set(peer_t peer, connection_t remote_peer)
268 if ((remote_peer->interested != 0) && (remote_peer->choked_upload == 0)) {
269 //add in the active peers set
270 xbt_dict_set_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int), remote_peer, NULL);
271 } else if (xbt_dict_get_or_null_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int))) {
272 xbt_dict_remove_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int));
276 /** @brief Handle a received message sent by another peer
277 * @param peer Peer data
278 * @param task task received.
280 void handle_message(peer_t peer, msg_task_t task)
282 const char* type_names[10] =
283 {"HANDSHAKE","CHOKE","UNCHOKE","INTERESTED","NOTINTERESTED","HAVE","BITFIELD","REQUEST", "PIECE", "CANCEL" };
284 message_t message = MSG_task_get_data(task);
285 XBT_DEBUG("Received a %s message from %s (%s)", type_names[message->type], message->mailbox,
286 message->issuer_host_name);
288 connection_t remote_peer;
289 remote_peer = xbt_dict_get_or_null_ext(peer->peers, (char *) &message->peer_id, sizeof(int));
291 switch (message->type) {
292 case MESSAGE_HANDSHAKE:
293 //Check if the peer is in our connection list.
294 if (remote_peer == 0) {
295 xbt_dict_set_ext(peer->peers, (char *) &message->peer_id, sizeof(int), connection_new(message->peer_id), NULL);
296 send_handshake(peer, message->mailbox);
298 //Send our bitfield to the peer
299 send_bitfield(peer, message->mailbox);
301 case MESSAGE_BITFIELD:
302 //Update the pieces list
303 update_pieces_count_from_bitfield(peer, message->bitfield);
305 remote_peer->bitfield = xbt_strdup(message->bitfield);
306 xbt_assert(!remote_peer->am_interested, "Should not be interested at first");
307 if (is_interested(peer, remote_peer)) {
308 remote_peer->am_interested = 1;
309 send_interested(peer, message->mailbox);
312 case MESSAGE_INTERESTED:
313 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
314 //Update the interested state of the peer.
315 remote_peer->interested = 1;
316 update_active_peers_set(peer, remote_peer);
318 case MESSAGE_NOTINTERESTED:
319 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
320 remote_peer->interested = 0;
321 update_active_peers_set(peer, remote_peer);
323 case MESSAGE_UNCHOKE:
324 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
325 xbt_assert(remote_peer->choked_download);
326 remote_peer->choked_download = 0;
327 //Send requests to the peer, since it has unchoked us
328 if (remote_peer->am_interested)
329 request_new_piece_to_peer(peer, remote_peer);
332 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
333 xbt_assert(!remote_peer->choked_download);
334 remote_peer->choked_download = 1;
335 remove_current_piece(peer, remote_peer, remote_peer->current_piece);
338 XBT_DEBUG("\t for piece %d", message->index);
339 xbt_assert(remote_peer->bitfield, "bitfield not received");
340 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
341 remote_peer->bitfield[message->index] = '1';
342 peer->pieces_count[message->index]++;
343 //If the piece is in our pieces, we tell the peer that we are interested.
344 if ((remote_peer->am_interested == 0) && peer->bitfield[message->index] == '0') {
345 remote_peer->am_interested = 1;
346 send_interested(peer, message->mailbox);
347 if (remote_peer->choked_download == 0)
348 request_new_piece_to_peer(peer, remote_peer);
351 case MESSAGE_REQUEST:
352 xbt_assert(remote_peer->interested);
353 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
354 if (remote_peer->choked_upload == 0) {
355 XBT_DEBUG("\t for piece %d (%d,%d)", message->index, message->block_index,
356 message->block_index + message->block_length);
357 if (peer->bitfield[message->index] == '1') {
358 send_piece(peer, message->mailbox, message->index, message->block_index, message->block_length);
361 XBT_DEBUG("\t for piece %d but he is choked.", message->peer_id);
365 XBT_DEBUG(" \for piece %d (%d,%d)", message->index, message->block_index,
366 message->block_index + message->block_length);
367 xbt_assert(!remote_peer->choked_download);
368 xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
369 "Can't received a piece if I'm not interested wihtout end-game mode!"
370 "piece (%d) bitfield(%s) remote bitfield(%s)", message->index, peer->bitfield, remote_peer->bitfield);
371 xbt_assert(remote_peer->choked_download != 1, "Can't received a piece if I'm choked !");
372 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
373 //TODO: Execute à computation.
374 if (peer->bitfield[message->index] == '0') {
375 update_bitfield_blocks(peer, message->index, message->block_index, message->block_length);
376 if (piece_complete(peer, message->index)) {
377 //Removing the piece from our piece list
378 remove_current_piece(peer, remote_peer, message->index);
379 //Setting the fact that we have the piece
380 peer->bitfield[message->index] = '1';
382 XBT_DEBUG("My status is now %s", peer->bitfield);
383 //Sending the information to all the peers we are connected to
384 send_have(peer, message->index);
385 //sending UNINTERESTED to peers that do not have what we want.
386 update_interested_after_receive(peer);
387 } else { // piece not completed
388 send_request_to_peer(peer, remote_peer, message->index); // ask for the next block
391 XBT_DEBUG("However, we already have it");
392 xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
393 request_new_piece_to_peer(peer, remote_peer);
401 //Update the peer speed.
403 connection_add_speed_value(remote_peer, 1.0 / (MSG_get_clock() - peer->begin_receive_time));
405 peer->begin_receive_time = MSG_get_clock();
407 task_message_free(task);
410 /** Selects the appropriate piece to download and requests it to the remote_peer */
411 void request_new_piece_to_peer(peer_t peer, connection_t remote_peer)
413 int piece = select_piece_to_download(peer, remote_peer);
415 xbt_dynar_push_as(peer->current_pieces, int, piece);
416 send_request_to_peer(peer, remote_peer, piece);
420 /** remove current_piece from the list of currently downloaded pieces. */
421 void remove_current_piece(peer_t peer, connection_t remote_peer, int current_piece)
423 int piece_index = xbt_dynar_search_or_negative(peer->current_pieces, ¤t_piece);
424 if (piece_index != -1)
425 xbt_dynar_remove_at(peer->current_pieces, piece_index, NULL);
426 remote_peer->current_piece = -1;
429 /** @brief Updates the list of who has a piece from a bitfield
430 * @param peer peer we want to update the list
431 * @param bitfield bitfield
433 void update_pieces_count_from_bitfield(peer_t peer, char *bitfield)
435 for (int i = 0; i < FILE_PIECES; i++) {
436 if (bitfield[i] == '1') {
437 peer->pieces_count[i]++;
442 /** @brief Return the piece to be downloaded
443 * There are two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
444 * If a piece is partially downloaded, this piece will be selected prioritarily
445 * If the peer has strictly less than 4 pieces, he chooses a piece at random.
446 * If the peer has more than pieces, he downloads the pieces that are the less replicated (rarest policy).
447 * If all pieces have been downloaded or requested, we select a random requested piece (endgame mode).
448 * @param peer: local peer
449 * @param remote_peer: information about the connection
450 * @return the piece to download if possible. -1 otherwise
452 int select_piece_to_download(peer_t peer, connection_t remote_peer)
454 int piece = partially_downloaded_piece(peer, remote_peer);
455 // strict priority policy
460 if (xbt_dynar_length(peer->current_pieces) >= (FILE_PIECES - peer->pieces) &&
461 (is_interested(peer, remote_peer) != 0)) {
462 #if ENABLE_END_GAME_MODE == 0
465 int nb_interesting_pieces = 0;
466 // compute the number of interesting pieces
467 for (int i = 0; i < FILE_PIECES; i++) {
468 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1') {
469 nb_interesting_pieces++;
472 xbt_assert(nb_interesting_pieces != 0);
473 // get a random interesting piece
474 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
475 int current_index = 0;
476 for (int i = 0; i < FILE_PIECES; i++) {
477 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1') {
478 if (random_piece_index == current_index) {
485 xbt_assert(piece != -1);
488 // Random first policy
489 if (peer->pieces < 4 && (is_interested_and_free(peer, remote_peer) != 0)) {
490 int nb_interesting_pieces = 0;
491 // compute the number of interesting pieces
492 for (int i = 0; i < FILE_PIECES; i++) {
493 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1' &&
494 (in_current_pieces(peer, i) == 0)) {
495 nb_interesting_pieces++;
498 xbt_assert(nb_interesting_pieces != 0);
499 // get a random interesting piece
500 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
501 int current_index = 0;
502 for (int i = 0; i < FILE_PIECES; i++) {
503 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1' &&
504 (in_current_pieces(peer, i) == 0)) {
505 if (random_piece_index == current_index) {
512 xbt_assert(piece != -1);
514 } else { // Rarest first policy
515 short min = SHRT_MAX;
516 int nb_min_pieces = 0;
517 int current_index = 0;
518 // compute the smallest number of copies of available pieces
519 for (int i = 0; i < FILE_PIECES; i++) {
520 if (peer->pieces_count[i] < min && peer->bitfield[i] == '0' &&
521 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i) == 0))
522 min = peer->pieces_count[i];
524 xbt_assert(min != SHRT_MAX || (is_interested_and_free(peer, remote_peer) ==0));
525 // compute the number of rarest pieces
526 for (int i = 0; i < FILE_PIECES; i++) {
527 if (peer->pieces_count[i] == min && peer->bitfield[i] == '0' &&
528 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i) ==0))
531 xbt_assert(nb_min_pieces != 0 || (is_interested_and_free(peer, remote_peer)==0));
532 // get a random rarest piece
533 int random_rarest_index = RngStream_RandInt(peer->stream, 0, nb_min_pieces - 1);
534 for (int i = 0; i < FILE_PIECES; i++) {
535 if (peer->pieces_count[i] == min && peer->bitfield[i] == '0' &&
536 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i)==0)) {
537 if (random_rarest_index == current_index) {
544 xbt_assert(piece != -1 || (is_interested_and_free(peer, remote_peer) == 0));
549 /** @brief Update the list of current choked and unchoked peers, using the choke algorithm
550 * @param peer the current peer
552 void update_choked_peers(peer_t peer)
554 if (nb_interested_peers(peer) == 0)
556 XBT_DEBUG("(%d) update_choked peers %d active peers", peer->id, xbt_dict_size(peer->active_peers));
557 //update the current round
558 peer->round = (peer->round + 1) % 3;
560 char *key_choked=NULL;
561 connection_t peer_choosed = NULL;
562 connection_t peer_choked = NULL;
563 //remove a peer from the list
564 xbt_dict_cursor_t cursor = NULL;
565 xbt_dict_cursor_first(peer->active_peers, &cursor);
566 if (xbt_dict_length(peer->active_peers) > 0) {
567 key_choked = xbt_dict_cursor_get_key(cursor);
568 peer_choked = xbt_dict_cursor_get_data(cursor);
570 xbt_dict_cursor_free(&cursor);
572 /**If we are currently seeding, we unchoke the peer which has been unchoked the last time.*/
573 if (peer->pieces == FILE_PIECES) {
574 connection_t connection;
575 double unchoke_time = MSG_get_clock() + 1;
577 xbt_dict_foreach(peer->peers, cursor, key, connection) {
578 if (connection->last_unchoke < unchoke_time &&
579 (connection->interested != 0) && (connection->choked_upload != 0)) {
580 unchoke_time = connection->last_unchoke;
581 peer_choosed = connection;
585 //Random optimistic unchoking
586 if (peer->round == 0) {
589 //We choose a random peer to unchoke.
590 int id_chosen = RngStream_RandInt(peer->stream, 0, xbt_dict_length(peer->peers) - 1);
592 connection_t connection;
593 xbt_dict_foreach(peer->peers, cursor, key, connection) {
594 if (i == id_chosen) {
595 peer_choosed = connection;
600 xbt_dict_cursor_free(&cursor);
601 if (peer_choosed == NULL)
602 THROWF(unknown_error, 0, "A peer should have be selected at this point");
603 else if ((peer_choosed->interested == 0) || (peer_choosed->choked_upload == 0))
606 XBT_DEBUG("Nothing to do, keep going");
608 } while (peer_choosed == NULL && j < MAXIMUM_PAIRS);
610 //Use the "fastest download" policy.
611 connection_t connection;
612 double fastest_speed = 0.0;
613 xbt_dict_foreach(peer->peers, cursor, key, connection) {
614 if (connection->peer_speed > fastest_speed &&
615 (connection->choked_upload != 0) && (connection->interested != 0)) {
616 peer_choosed = connection;
617 fastest_speed = connection->peer_speed;
623 if (peer_choosed != NULL)
624 XBT_DEBUG("(%d) update_choked peers unchoked (%d) ; int (%d) ; choked (%d) ",
625 peer->id, peer_choosed->id, peer_choosed->interested, peer_choosed->choked_upload);
627 if (peer_choked != peer_choosed) {
628 if (peer_choked != NULL) {
629 xbt_assert((!peer_choked->choked_upload), "Tries to choked a choked peer");
630 peer_choked->choked_upload = 1;
631 xbt_assert((*((int *) key_choked) == peer_choked->id));
632 update_active_peers_set(peer, peer_choked);
633 XBT_DEBUG("(%d) Sending a CHOKE to %d", peer->id, peer_choked->id);
634 send_choked(peer, peer_choked->mailbox);
636 if (peer_choosed != NULL) {
637 xbt_assert((peer_choosed->choked_upload), "Tries to unchoked an unchoked peer");
638 peer_choosed->choked_upload = 0;
639 xbt_dict_set_ext(peer->active_peers, (char *) &peer_choosed->id, sizeof(int), peer_choosed, NULL);
640 peer_choosed->last_unchoke = MSG_get_clock();
641 XBT_DEBUG("(%d) Sending a UNCHOKE to %d", peer->id, peer_choosed->id);
642 update_active_peers_set(peer, peer_choosed);
643 send_unchoked(peer, peer_choosed->mailbox);
648 /** @brief Update "interested" state of peers: send "not interested" to peers that don't have any more pieces we want.
649 * @param peer our peer data
651 void update_interested_after_receive(peer_t peer)
654 xbt_dict_cursor_t cursor;
655 connection_t connection;
657 xbt_dict_foreach(peer->peers, cursor, key, connection) {
659 if (connection->am_interested != 0) {
660 xbt_assert(connection->bitfield, "Bitfield not received");
661 //Check if the peer still has a piece we want.
662 for (int i = 0; i < FILE_PIECES; i++) {
663 if (connection->bitfield[i] == '1' && peer->bitfield[i] == '0') {
668 if (!interested) { //no more piece to download from connection
669 connection->am_interested = 0;
670 send_notinterested(peer, connection->mailbox);
676 void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length)
678 xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
679 xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.", block_index);
680 for (int i = block_index; i < (block_index + block_length); i++) {
681 peer->bitfield_blocks[index * PIECES_BLOCKS + i] = '1';
685 /** Returns if a peer has completed the download of a piece */
686 int piece_complete(peer_t peer, int index)
688 for (int i = 0; i < PIECES_BLOCKS; i++) {
689 if (peer->bitfield_blocks[index * PIECES_BLOCKS + i] == '0') {
696 /** Returns the first block that a peer doesn't have in a piece. If the peer has all blocks of the piece, returns -1. */
697 int get_first_block(peer_t peer, int piece)
699 for (int i = 0; i < PIECES_BLOCKS; i++) {
700 if (peer->bitfield_blocks[piece * PIECES_BLOCKS + i] == '0') {
707 /** Indicates if the remote peer has a piece not stored by the local peer */
708 int is_interested(peer_t peer, connection_t remote_peer)
710 xbt_assert(remote_peer->bitfield, "Bitfield not received");
711 for (int i = 0; i < FILE_PIECES; i++) {
712 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0') {
719 /** Indicates if the remote peer has a piece not stored by the local peer nor requested by the local peer */
720 int is_interested_and_free(peer_t peer, connection_t remote_peer)
722 xbt_assert(remote_peer->bitfield, "Bitfield not received");
723 for (int i = 0; i < FILE_PIECES; i++) {
724 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0' &&
725 (in_current_pieces(peer, i) == 0)) {
732 /** Returns a piece that is partially downloaded and stored by the remote peer if any -1 otherwise. */
733 int partially_downloaded_piece(peer_t peer, connection_t remote_peer)
735 xbt_assert(remote_peer->bitfield, "Bitfield not received");
736 for (int i = 0; i < FILE_PIECES; i++) {
737 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0' &&
738 (in_current_pieces(peer, i) == 0)) {
739 if (get_first_block(peer, i) > 0)
746 /** @brief Send request messages to a peer that have unchoked us
748 * @param remote_peer peer data to the peer we want to send the request
750 void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece)
752 remote_peer->current_piece = piece;
753 xbt_assert(remote_peer->bitfield, "bitfield not received");
754 xbt_assert(remote_peer->bitfield[piece] == '1');
755 int block_index = get_first_block(peer, piece);
756 if (block_index != -1) {
757 int block_length = MIN(BLOCKS_REQUESTED, PIECES_BLOCKS - block_index);
758 send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
762 /** Indicates if a piece is currently being downloaded by the peer. */
763 int in_current_pieces(peer_t peer, int piece)
765 return xbt_dynar_member(peer->current_pieces, &piece);
768 /***********************************************************
770 * Low level message functions
772 ***********************************************************/
774 /** @brief Send a "interested" message to a peer
775 * @param peer peer data
776 * @param mailbox destination mailbox
778 void send_interested(peer_t peer, const char *mailbox)
780 msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id,
781 task_message_size(MESSAGE_INTERESTED));
782 MSG_task_dsend(task, mailbox, task_message_free);
783 XBT_DEBUG("Sending INTERESTED to %s", mailbox);
786 /** @brief Send a "not interested" message to a peer
787 * @param peer peer data
788 * @param mailbox destination mailbox
790 void send_notinterested(peer_t peer, const char *mailbox)
792 msg_task_t task = task_message_new(MESSAGE_NOTINTERESTED, peer->hostname, peer->mailbox, peer->id,
793 task_message_size(MESSAGE_NOTINTERESTED));
794 MSG_task_dsend(task, mailbox, task_message_free);
795 XBT_DEBUG("Sending NOTINTERESTED to %s", mailbox);
798 /** @brief Send a handshake message to all the peers the peer has.
799 * @param peer peer data
801 void send_handshake_all(peer_t peer)
803 connection_t remote_peer;
804 xbt_dict_cursor_t cursor = NULL;
806 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
807 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
808 task_message_size(MESSAGE_HANDSHAKE));
809 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
810 XBT_DEBUG("Sending a HANDSHAKE to %s", remote_peer->mailbox);
814 /** @brief Send a "handshake" message to an user
815 * @param peer peer data
816 * @param mailbox mailbox where to we send the message
818 void send_handshake(peer_t peer, const char *mailbox)
820 XBT_DEBUG("Sending a HANDSHAKE to %s", mailbox);
821 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
822 task_message_size(MESSAGE_HANDSHAKE));
823 MSG_task_dsend(task, mailbox, task_message_free);
826 /** Send a "choked" message to a peer. */
827 void send_choked(peer_t peer, const char *mailbox)
829 XBT_DEBUG("Sending a CHOKE to %s", mailbox);
830 msg_task_t task = task_message_new(MESSAGE_CHOKE, peer->hostname, peer->mailbox, peer->id,
831 task_message_size(MESSAGE_CHOKE));
832 MSG_task_dsend(task, mailbox, task_message_free);
835 /** Send a "unchoked" message to a peer */
836 void send_unchoked(peer_t peer, const char *mailbox)
838 XBT_DEBUG("Sending a UNCHOKE to %s", mailbox);
839 msg_task_t task = task_message_new(MESSAGE_UNCHOKE, peer->hostname, peer->mailbox, peer->id,
840 task_message_size(MESSAGE_UNCHOKE));
841 MSG_task_dsend(task, mailbox, task_message_free);
844 /** Send a "HAVE" message to all peers we are connected to */
845 void send_have(peer_t peer, int piece)
847 XBT_DEBUG("Sending HAVE message to all my peers");
848 connection_t remote_peer;
849 xbt_dict_cursor_t cursor = NULL;
851 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
852 msg_task_t task = task_message_index_new(MESSAGE_HAVE, peer->hostname, peer->mailbox, peer->id, piece,
853 task_message_size(MESSAGE_HAVE));
854 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
858 /** @brief Send a bitfield message to all the peers the peer has.
859 * @param peer peer data
861 void send_bitfield(peer_t peer, const char *mailbox)
863 XBT_DEBUG("Sending a BITFIELD to %s", mailbox);
864 msg_task_t task = task_message_bitfield_new(peer->hostname, peer->mailbox, peer->id, peer->bitfield, FILE_PIECES);
865 MSG_task_dsend(task, mailbox, task_message_free);
868 /** Send a "request" message to a pair, containing a request for a piece */
869 void send_request(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
871 XBT_DEBUG("Sending a REQUEST to %s for piece %d (%d,%d)", mailbox, piece, block_index, block_length);
872 msg_task_t task = task_message_request_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length);
873 MSG_task_dsend(task, mailbox, task_message_free);
876 /** Send a "piece" message to a pair, containing a piece of the file */
877 void send_piece(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
879 XBT_DEBUG("Sending the PIECE %d (%d,%d) to %s", piece, block_index, block_length, mailbox);
880 xbt_assert(piece >= 0, "Tried to send a piece that doesn't exist.");
881 xbt_assert((peer->bitfield[piece] == '1'), "Tried to send a piece that we doesn't have.");
882 msg_task_t task = task_message_piece_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length,
884 MSG_task_dsend(task, mailbox, task_message_free);