1 /* Copyright (c) 2012-2016. 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");
16 //TODO: Let users change this
18 * File transfered data
19 * For the test, default values are :
20 * File size: 10 pieces * 5 blocks/piece * 16384 bytes/block = 819200 bytes
23 #define FILE_PIECES 10
24 #define PIECES_BLOCKS 5
25 #define BLOCK_SIZE 16384
26 #define ENABLE_END_GAME_MODE 1
28 /** Number of blocks asked by each request */
29 #define BLOCKS_REQUESTED 2
31 static const unsigned long int FILE_SIZE = FILE_PIECES * PIECES_BLOCKS * BLOCK_SIZE;
33 #define SLEEP_DURATION 1
35 /** Peer main function */
36 int peer(int argc, char *argv[])
40 xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
43 peer_init(&peer, xbt_str_parse_int(argv[1],"Invalid ID: %s"), 1);
45 peer_init(&peer, xbt_str_parse_int(argv[1],"Invalid ID: %s"), 0);
48 double deadline = xbt_str_parse_double(argv[2],"Invalid deadline: %s");
49 xbt_assert(deadline > 0, "Wrong deadline supplied");
50 XBT_INFO("Hi, I'm joining the network with id %d", peer.id);
51 //Getting peer data from the tracker.
52 if (get_peers_data(&peer)) {
53 XBT_DEBUG("Got %d peers from the tracker", xbt_dict_length(peer.peers));
54 XBT_DEBUG("Here is my current status: %s", peer.bitfield);
55 peer.begin_receive_time = MSG_get_clock();
56 MSG_mailbox_set_async(peer.mailbox);
57 if (has_finished(peer.bitfield)) {
58 peer.pieces = FILE_PIECES;
59 send_handshake_all(&peer);
60 seed_loop(&peer, deadline);
62 leech_loop(&peer, deadline);
63 seed_loop(&peer, deadline);
66 XBT_INFO("Couldn't contact the tracker.");
69 XBT_INFO("Here is my current status: %s", peer.bitfield);
70 if (peer.comm_received) {
71 MSG_comm_destroy(peer.comm_received);
78 /** @brief Peer main loop when it is leeching.
79 * @param peer peer data
80 * @param deadline time at which the peer has to leave
82 void leech_loop(peer_t peer, double deadline)
84 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
85 XBT_DEBUG("Start downloading.");
87 * Send a "handshake" message to all the peers it got
88 * (since it couldn't have gotten more than 50 peers)
90 send_handshake_all(peer);
91 XBT_DEBUG("Starting main leech loop");
93 while (MSG_get_clock() < deadline && peer->pieces < FILE_PIECES) {
94 if (peer->comm_received == NULL) {
95 peer->task_received = NULL;
96 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
98 if (MSG_comm_test(peer->comm_received)) {
99 msg_error_t status = MSG_comm_get_status(peer->comm_received);
100 MSG_comm_destroy(peer->comm_received);
101 peer->comm_received = NULL;
102 if (status == MSG_OK) {
103 handle_message(peer, peer->task_received);
106 //We don't execute the choke algorithm if we don't already have a piece
107 if (MSG_get_clock() >= next_choked_update && peer->pieces > 0) {
108 update_choked_peers(peer);
109 next_choked_update += UPDATE_CHOKED_INTERVAL;
111 MSG_process_sleep(SLEEP_DURATION);
115 if (peer->pieces == FILE_PIECES)
116 XBT_DEBUG("%d becomes a seeder", peer->id);
120 /** @brief Peer main loop when it is seeding
121 * @param peer peer data
122 * @param deadline time when the peer will leave
124 void seed_loop(peer_t peer, double deadline)
126 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
127 XBT_DEBUG("Start seeding.");
128 //start the main seed loop
129 while (MSG_get_clock() < deadline) {
130 if (peer->comm_received == NULL) {
131 peer->task_received = NULL;
132 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
134 if (MSG_comm_test(peer->comm_received)) {
135 msg_error_t status = MSG_comm_get_status(peer->comm_received);
136 MSG_comm_destroy(peer->comm_received);
137 peer->comm_received = NULL;
138 if (status == MSG_OK) {
139 handle_message(peer, peer->task_received);
142 if (MSG_get_clock() >= next_choked_update) {
143 update_choked_peers(peer);
144 //TODO: Change the choked peer algorithm when seeding.
145 next_choked_update += UPDATE_CHOKED_INTERVAL;
147 MSG_process_sleep(SLEEP_DURATION);
153 /** @brief Retrieves the peer list from the tracker
154 * @param peer current peer data
156 int get_peers_data(peer_t peer)
159 int send_success = 0;
160 double timeout = MSG_get_clock() + GET_PEERS_TIMEOUT;
161 //Build the task to send to the tracker
162 tracker_task_data_t data = tracker_task_data_new(MSG_host_get_name(MSG_host_self()), peer->mailbox_tracker,
163 peer->id, 0, 0, FILE_SIZE);
164 //Build the task to send.
165 msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
166 msg_task_t task_received = NULL;
167 msg_comm_t comm_received;
168 while ((send_success == 0) && MSG_get_clock() < timeout) {
169 XBT_DEBUG("Sending a peer request to the tracker.");
170 msg_error_t status = MSG_task_send_with_timeout(task_send, TRACKER_MAILBOX, GET_PEERS_TIMEOUT);
171 if (status == MSG_OK) {
175 while ((success ==0) && MSG_get_clock() < timeout) {
176 comm_received = MSG_task_irecv(&task_received, peer->mailbox_tracker);
177 msg_error_t status = MSG_comm_wait(comm_received, GET_PEERS_TIMEOUT);
178 if (status == MSG_OK) {
179 tracker_task_data_t data = MSG_task_get_data(task_received);
182 //Add the peers the tracker gave us to our peer list.
183 xbt_dynar_foreach(data->peers, i, peer_id) {
184 if (peer_id != peer->id)
185 xbt_dict_set_ext(peer->peers, (char *) &peer_id, sizeof(int), connection_new(peer_id), NULL);
188 //free the communication and the task
189 MSG_comm_destroy(comm_received);
190 tracker_task_data_free(data);
191 MSG_task_destroy(task_received);
198 /** @brief Initialize the peer data.
199 * @param peer peer data
200 * @param id id of the peer to take in the network
201 * @param seed indicates if the peer is a seed.
203 void peer_init(peer_t peer, int id, int seed)
206 snprintf(peer->mailbox,MAILBOX_SIZE-1, "%d", id);
207 snprintf(peer->mailbox_tracker,MAILBOX_SIZE-1, "tracker_%d", id);
208 peer->peers = xbt_dict_new_homogeneous(NULL);
209 peer->active_peers = xbt_dict_new_homogeneous(NULL);
210 peer->hostname = MSG_host_get_name(MSG_host_self());
212 peer->bitfield = xbt_new(char, FILE_PIECES + 1);
213 peer->bitfield_blocks = xbt_new(char, (FILE_PIECES) * (PIECES_BLOCKS) + 1);
215 memset(peer->bitfield, '1', sizeof(char) * (FILE_PIECES + 1));
216 memset(peer->bitfield_blocks, '1', sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
218 memset(peer->bitfield, '0', sizeof(char) * (FILE_PIECES + 1));
219 memset(peer->bitfield_blocks, '0', sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
222 peer->bitfield[FILE_PIECES] = '\0';
225 peer->pieces_count = xbt_new0(short, FILE_PIECES);
227 peer->current_pieces = xbt_dynar_new(sizeof(int), NULL);
229 peer->stream = (RngStream)MSG_host_get_data(MSG_host_self());
230 peer->comm_received = NULL;
235 /** Destroys a poor peer object. */
236 void peer_free(peer_t peer)
239 connection_t connection;
240 xbt_dict_cursor_t cursor;
241 xbt_dict_foreach(peer->peers, cursor, key, connection) {
242 connection_free(connection);
244 xbt_dict_free(&peer->peers);
245 xbt_dict_free(&peer->active_peers);
246 xbt_dynar_free(&peer->current_pieces);
247 xbt_free(peer->pieces_count);
248 xbt_free(peer->bitfield);
249 xbt_free(peer->bitfield_blocks);
252 /** @brief Returns if a peer has finished downloading the file
253 * @param bitfield peer bitfield
255 int has_finished(char *bitfield)
257 return ((memchr(bitfield, '0', sizeof(char) * FILE_PIECES) == NULL) ? 1 : 0);
260 int nb_interested_peers(peer_t peer)
262 xbt_dict_cursor_t cursor = NULL;
264 connection_t connection;
266 xbt_dict_foreach(peer->peers, cursor, key, connection) {
267 if (connection->interested)
273 void update_active_peers_set(peer_t peer, connection_t remote_peer)
275 if ((remote_peer->interested != 0) && (remote_peer->choked_upload == 0)) {
276 //add in the active peers set
277 xbt_dict_set_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int), remote_peer, NULL);
278 } else if (xbt_dict_get_or_null_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int))) {
279 xbt_dict_remove_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int));
283 /** @brief Handle a received message sent by another peer
284 * @param peer Peer data
285 * @param task task received.
287 void handle_message(peer_t peer, msg_task_t task)
289 message_t message = MSG_task_get_data(task);
290 connection_t remote_peer;
291 remote_peer = xbt_dict_get_or_null_ext(peer->peers, (char *) &message->peer_id, sizeof(int));
292 switch (message->type) {
293 case MESSAGE_HANDSHAKE:
294 XBT_DEBUG("Received a HANDSHAKE from %s (%s)", message->mailbox, message->issuer_host_name);
295 //Check if the peer is in our connection list.
296 if (remote_peer == 0) {
297 xbt_dict_set_ext(peer->peers, (char *) &message->peer_id, sizeof(int), connection_new(message->peer_id), NULL);
298 send_handshake(peer, message->mailbox);
300 //Send our bitfield to the peer
301 send_bitfield(peer, message->mailbox);
303 case MESSAGE_BITFIELD:
304 XBT_DEBUG("Recieved a BITFIELD message from %s (%s)", message->mailbox, message->issuer_host_name);
305 //Update the pieces list
306 update_pieces_count_from_bitfield(peer, message->bitfield);
308 remote_peer->bitfield = xbt_strdup(message->bitfield);
309 xbt_assert(!remote_peer->am_interested, "Should not be interested at first");
310 if (is_interested(peer, remote_peer)) {
311 remote_peer->am_interested = 1;
312 send_interested(peer, message->mailbox);
315 case MESSAGE_INTERESTED:
316 XBT_DEBUG("Recieved an INTERESTED message from %s (%s)", message->mailbox, message->issuer_host_name);
317 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
318 //Update the interested state of the peer.
319 remote_peer->interested = 1;
320 update_active_peers_set(peer, remote_peer);
322 case MESSAGE_NOTINTERESTED:
323 XBT_DEBUG("Received a NOTINTERESTED message from %s (%s)", message->mailbox, message->issuer_host_name);
324 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
325 remote_peer->interested = 0;
326 update_active_peers_set(peer, remote_peer);
328 case MESSAGE_UNCHOKE:
329 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
330 XBT_DEBUG("Received a UNCHOKE message from %s (%s)", message->mailbox, message->issuer_host_name);
331 xbt_assert(remote_peer->choked_download);
332 remote_peer->choked_download = 0;
333 //Send requests to the peer, since it has unchoked us
334 if (remote_peer->am_interested)
335 request_new_piece_to_peer(peer, remote_peer);
338 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
339 XBT_DEBUG("Received a CHOKE message from %s (%s)", message->mailbox, message->issuer_host_name);
340 xbt_assert(!remote_peer->choked_download);
341 remote_peer->choked_download = 1;
342 remove_current_piece(peer, remote_peer, remote_peer->current_piece);
345 XBT_DEBUG("Received a HAVE message from %s (%s) of piece %d", message->mailbox, message->issuer_host_name,
347 xbt_assert(remote_peer->bitfield, "bitfield not received");
348 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
349 remote_peer->bitfield[message->index] = '1';
350 peer->pieces_count[message->index]++;
351 //If the piece is in our pieces, we tell the peer that we are interested.
352 if ((remote_peer->am_interested == 0) &&
353 peer->bitfield[message->index] == '0') {
354 remote_peer->am_interested = 1;
355 send_interested(peer, message->mailbox);
356 if (remote_peer->choked_download == 0)
357 request_new_piece_to_peer(peer, remote_peer);
360 case MESSAGE_REQUEST:
361 xbt_assert(remote_peer->interested);
363 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
364 if (remote_peer->choked_upload == 0) {
365 XBT_DEBUG("Received a REQUEST from %s (%s) for %d (%d,%d)", message->mailbox, message->issuer_host_name,
366 message->index, message->block_index, message->block_index + message->block_length);
367 if (peer->bitfield[message->index] == '1') {
368 send_piece(peer, message->mailbox, message->index, message->block_index, message->block_length);
371 XBT_DEBUG("Received a REQUEST from %s (%s) for %d but he is choked.", message->mailbox,
372 message->issuer_host_name, message->peer_id);
376 XBT_DEBUG("Received piece %d (%d,%d) from %s (%s)", message->index, message->block_index,
377 message->block_index + message->block_length, message->mailbox, message->issuer_host_name);
378 xbt_assert(!remote_peer->choked_download);
379 xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
380 "Can't received a piece if I'm not interested wihtout end-game mode!"
381 "piece (%d) bitfield(%s) remote bitfield(%s)", message->index, peer->bitfield, remote_peer->bitfield);
382 xbt_assert(remote_peer->choked_download != 1, "Can't received a piece if I'm choked !");
383 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
384 //TODO: Execute à computation.
385 if (peer->bitfield[message->index] == '0') {
386 update_bitfield_blocks(peer, message->index, message->block_index, message->block_length);
387 if (piece_complete(peer, message->index)) {
388 //Removing the piece from our piece list
389 remove_current_piece(peer, remote_peer, message->index);
390 //Setting the fact that we have the piece
391 peer->bitfield[message->index] = '1';
393 XBT_DEBUG("My status is now %s", peer->bitfield);
394 //Sending the information to all the peers we are connected to
395 send_have(peer, message->index);
396 //sending UNINTERSTED to peers that doesn't have what we want.
397 update_interested_after_receive(peer);
398 } else { // piece not completed
399 send_request_to_peer(peer, remote_peer, message->index); // ask for the next block
402 XBT_DEBUG("However, we already have it");
403 xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
404 request_new_piece_to_peer(peer, remote_peer);
408 XBT_DEBUG("The received CANCEL from %s (%s)", message->mailbox, message->issuer_host_name);
413 //Update the peer speed.
415 connection_add_speed_value(remote_peer, 1.0 / (MSG_get_clock() - peer->begin_receive_time));
417 peer->begin_receive_time = MSG_get_clock();
419 task_message_free(task);
422 /** Selects the appropriate piece to download and requests it to the remote_peer */
423 void request_new_piece_to_peer(peer_t peer, connection_t remote_peer)
425 int piece = select_piece_to_download(peer, remote_peer);
427 xbt_dynar_push_as(peer->current_pieces, int, piece);
428 send_request_to_peer(peer, remote_peer, piece);
432 /** remove current_piece from the list of currently downloaded pieces. */
433 void remove_current_piece(peer_t peer, connection_t remote_peer, int current_piece)
435 int piece_index = xbt_dynar_search_or_negative(peer->current_pieces, ¤t_piece);
436 if (piece_index != -1)
437 xbt_dynar_remove_at(peer->current_pieces, piece_index, NULL);
438 remote_peer->current_piece = -1;
441 /** @brief Updates the list of who has a piece from a bitfield
442 * @param peer peer we want to update the list
443 * @param bitfield bitfield
445 void update_pieces_count_from_bitfield(peer_t peer, char *bitfield)
448 for (i = 0; i < FILE_PIECES; i++) {
449 if (bitfield[i] == '1') {
450 peer->pieces_count[i]++;
455 /** @brief Return the piece to be downloaded
456 * There are two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
457 * If a piece is partially downloaded, this piece will be selected prioritarily
458 * If the peer has strictly less than 4 pieces, he chooses a piece at random.
459 * If the peer has more than pieces, he downloads the pieces that are the less replicated (rarest policy).
460 * If all pieces have been downloaded or requested, we select a random requested piece (endgame mode).
461 * @param peer: local peer
462 * @param remote_peer: information about the connection
463 * @return the piece to download if possible. -1 otherwise
465 int select_piece_to_download(peer_t peer, connection_t remote_peer)
467 int piece = partially_downloaded_piece(peer, remote_peer);
468 // strict priority policy
473 if (xbt_dynar_length(peer->current_pieces) >= (FILE_PIECES - peer->pieces) &&
474 (is_interested(peer, remote_peer) != 0)) {
475 #if ENABLE_END_GAME_MODE == 0
479 int nb_interesting_pieces = 0;
480 int current_index = 0;
481 // compute the number of interesting pieces
482 for (i = 0; i < FILE_PIECES; i++) {
483 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1') {
484 nb_interesting_pieces++;
487 xbt_assert(nb_interesting_pieces != 0);
488 // get a random interesting piece
489 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
490 for (i = 0; i < FILE_PIECES; i++) {
491 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1') {
492 if (random_piece_index == current_index) {
499 xbt_assert(piece != -1);
502 // Random first policy
503 if (peer->pieces < 4 && (is_interested_and_free(peer, remote_peer) != 0)) {
505 int nb_interesting_pieces = 0;
506 int current_index = 0;
507 // compute the number of interesting pieces
508 for (i = 0; i < FILE_PIECES; i++) {
509 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1' &&
510 (in_current_pieces(peer, i) == 0)) {
511 nb_interesting_pieces++;
514 xbt_assert(nb_interesting_pieces != 0);
515 // get a random interesting piece
516 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
517 for (i = 0; i < FILE_PIECES; i++) {
518 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1' &&
519 (in_current_pieces(peer, i) == 0)) {
520 if (random_piece_index == current_index) {
527 xbt_assert(piece != -1);
529 } else { // Rarest first policy
531 short min = SHRT_MAX;
532 int nb_min_pieces = 0;
533 int current_index = 0;
534 // compute the smallest number of copies of available pieces
535 for (i = 0; i < FILE_PIECES; i++) {
536 if (peer->pieces_count[i] < min && peer->bitfield[i] == '0' &&
537 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i) == 0))
538 min = peer->pieces_count[i];
540 xbt_assert(min != SHRT_MAX ||
541 (is_interested_and_free(peer, remote_peer) ==0));
542 // compute the number of rarest pieces
543 for (i = 0; i < FILE_PIECES; i++) {
544 if (peer->pieces_count[i] == min && peer->bitfield[i] == '0' &&
545 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i) ==0))
548 xbt_assert(nb_min_pieces != 0 ||
549 (is_interested_and_free(peer, remote_peer)==0));
550 // get a random rarest piece
551 int random_rarest_index = RngStream_RandInt(peer->stream, 0, nb_min_pieces - 1);
552 for (i = 0; i < FILE_PIECES; i++) {
553 if (peer->pieces_count[i] == min && peer->bitfield[i] == '0' &&
554 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i)==0)) {
555 if (random_rarest_index == current_index) {
562 xbt_assert(piece != -1 || (is_interested_and_free(peer, remote_peer) == 0));
567 /** @brief Update the list of current choked and unchoked peers, using the choke algorithm
568 * @param peer the current peer
570 void update_choked_peers(peer_t peer)
572 if (nb_interested_peers(peer) == 0)
574 XBT_DEBUG("(%d) update_choked peers %d active peers", peer->id, xbt_dict_size(peer->active_peers));
575 //update the current round
576 peer->round = (peer->round + 1) % 3;
578 char *key_choked=NULL;
579 connection_t peer_choosed = NULL;
580 connection_t peer_choked = NULL;
581 //remove a peer from the list
582 xbt_dict_cursor_t cursor = NULL;
583 xbt_dict_cursor_first(peer->active_peers, &cursor);
584 if (xbt_dict_length(peer->active_peers) > 0) {
585 key_choked = xbt_dict_cursor_get_key(cursor);
586 peer_choked = xbt_dict_cursor_get_data(cursor);
588 xbt_dict_cursor_free(&cursor);
590 /**If we are currently seeding, we unchoke the peer which has been unchoked the last time.*/
591 if (peer->pieces == FILE_PIECES) {
592 connection_t connection;
593 double unchoke_time = MSG_get_clock() + 1;
595 xbt_dict_foreach(peer->peers, cursor, key, connection) {
596 if (connection->last_unchoke < unchoke_time &&
597 (connection->interested != 0) && (connection->choked_upload != 0)) {
598 unchoke_time = connection->last_unchoke;
599 peer_choosed = connection;
603 //Random optimistic unchoking
604 if (peer->round == 0) {
607 //We choose a random peer to unchoke.
608 int id_chosen = RngStream_RandInt(peer->stream, 0, xbt_dict_length(peer->peers) - 1);
610 connection_t connection;
611 xbt_dict_foreach(peer->peers, cursor, key, connection) {
612 if (i == id_chosen) {
613 peer_choosed = connection;
618 xbt_dict_cursor_free(&cursor);
619 if (peer_choosed == NULL)
620 THROWF(unknown_error, 0, "A peer should have be selected at this point");
621 else if ((peer_choosed->interested == 0) || (peer_choosed->choked_upload == 0))
624 XBT_DEBUG("Nothing to do, keep going");
626 } while (peer_choosed == NULL && j < MAXIMUM_PAIRS);
628 //Use the "fastest download" policy.
629 connection_t connection;
630 double fastest_speed = 0.0;
631 xbt_dict_foreach(peer->peers, cursor, key, connection) {
632 if (connection->peer_speed > fastest_speed &&
633 (connection->choked_upload != 0) && (connection->interested != 0)) {
634 peer_choosed = connection;
635 fastest_speed = connection->peer_speed;
641 if (peer_choosed != NULL)
642 XBT_DEBUG("(%d) update_choked peers unchoked (%d) ; int (%d) ; choked (%d) ",
643 peer->id, peer_choosed->id, peer_choosed->interested, peer_choosed->choked_upload);
645 if (peer_choked != peer_choosed) {
646 if (peer_choked != NULL) {
647 xbt_assert((!peer_choked->choked_upload), "Tries to choked a choked peer");
648 peer_choked->choked_upload = 1;
649 xbt_assert((*((int *) key_choked) == peer_choked->id));
650 update_active_peers_set(peer, peer_choked);
651 XBT_DEBUG("(%d) Sending a CHOKE to %d", peer->id, peer_choked->id);
652 send_choked(peer, peer_choked->mailbox);
654 if (peer_choosed != NULL) {
655 xbt_assert((peer_choosed->choked_upload), "Tries to unchoked an unchoked peer");
656 peer_choosed->choked_upload = 0;
657 xbt_dict_set_ext(peer->active_peers, (char *) &peer_choosed->id, sizeof(int), peer_choosed, NULL);
658 peer_choosed->last_unchoke = MSG_get_clock();
659 XBT_DEBUG("(%d) Sending a UNCHOKE to %d", peer->id, peer_choosed->id);
660 update_active_peers_set(peer, peer_choosed);
661 send_unchoked(peer, peer_choosed->mailbox);
666 /** @brief Update "interested" state of peers: send "not interested" to peers that don't have any more pieces we want.
667 * @param peer our peer data
669 void update_interested_after_receive(peer_t peer)
672 xbt_dict_cursor_t cursor;
673 connection_t connection;
675 xbt_dict_foreach(peer->peers, cursor, key, connection) {
677 if (connection->am_interested != 0) {
678 xbt_assert(connection->bitfield, "Bitfield not received");
679 //Check if the peer still has a piece we want.
681 for (i = 0; i < FILE_PIECES; i++) {
682 if (connection->bitfield[i] == '1' && peer->bitfield[i] == '0') {
687 if (!interested) { //no more piece to download from connection
688 connection->am_interested = 0;
689 send_notinterested(peer, connection->mailbox);
695 void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length)
698 xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
699 xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.", block_index);
700 for (i = block_index; i < (block_index + block_length); i++) {
701 peer->bitfield_blocks[index * PIECES_BLOCKS + i] = '1';
705 /** Returns if a peer has completed the download of a piece */
706 int piece_complete(peer_t peer, int index)
709 for (i = 0; i < PIECES_BLOCKS; i++) {
710 if (peer->bitfield_blocks[index * PIECES_BLOCKS + i] == '0') {
717 /** Returns the first block that a peer doesn't have in a piece. If the peer has all blocks of the piece, returns -1. */
718 int get_first_block(peer_t peer, int piece)
721 for (i = 0; i < PIECES_BLOCKS; i++) {
722 if (peer->bitfield_blocks[piece * PIECES_BLOCKS + i] == '0') {
729 /** Indicates if the remote peer has a piece not stored by the local peer */
730 int is_interested(peer_t peer, connection_t remote_peer)
732 xbt_assert(remote_peer->bitfield, "Bitfield not received");
733 for (int i = 0; i < FILE_PIECES; i++) {
734 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0') {
741 /** Indicates if the remote peer has a piece not stored by the local peer nor requested by the local peer */
742 int is_interested_and_free(peer_t peer, connection_t remote_peer)
744 xbt_assert(remote_peer->bitfield, "Bitfield not received");
745 for (int i = 0; i < FILE_PIECES; i++) {
746 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0' &&
747 (in_current_pieces(peer, i) == 0)) {
754 /** Returns a piece that is partially downloaded and stored by the remote peer if any -1 otherwise. */
755 int partially_downloaded_piece(peer_t peer, connection_t remote_peer)
757 xbt_assert(remote_peer->bitfield, "Bitfield not received");
758 for (int i = 0; i < FILE_PIECES; i++) {
759 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0' &&
760 (in_current_pieces(peer, i) == 0)) {
761 if (get_first_block(peer, i) > 0)
768 /** @brief Send request messages to a peer that have unchoked us
770 * @param remote_peer peer data to the peer we want to send the request
772 void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece)
774 remote_peer->current_piece = piece;
775 xbt_assert(remote_peer->bitfield, "bitfield not received");
776 xbt_assert(remote_peer->bitfield[piece] == '1');
777 int block_index = get_first_block(peer, piece);
778 if (block_index != -1) {
779 int block_length = PIECES_BLOCKS - block_index;
780 block_length = MIN(BLOCKS_REQUESTED, block_length);
781 send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
785 /** Indicates if a piece is currently being downloaded by the peer. */
786 int in_current_pieces(peer_t peer, int piece)
788 return xbt_dynar_member(peer->current_pieces, &piece);
791 /***********************************************************
793 * Low level message functions
795 ***********************************************************/
797 /** @brief Send a "interested" message to a peer
798 * @param peer peer data
799 * @param mailbox destination mailbox
801 void send_interested(peer_t peer, const char *mailbox)
803 msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id,
804 task_message_size(MESSAGE_INTERESTED));
805 MSG_task_dsend(task, mailbox, task_message_free);
806 XBT_DEBUG("Sending INTERESTED to %s", mailbox);
809 /** @brief Send a "not interested" message to a peer
810 * @param peer peer data
811 * @param mailbox destination mailbox
813 void send_notinterested(peer_t peer, const char *mailbox)
815 msg_task_t task = task_message_new(MESSAGE_NOTINTERESTED, peer->hostname, peer->mailbox, peer->id,
816 task_message_size(MESSAGE_NOTINTERESTED));
817 MSG_task_dsend(task, mailbox, task_message_free);
818 XBT_DEBUG("Sending NOTINTERESTED to %s", mailbox);
821 /** @brief Send a handshake message to all the peers the peer has.
822 * @param peer peer data
824 void send_handshake_all(peer_t peer)
826 connection_t remote_peer;
827 xbt_dict_cursor_t cursor = NULL;
829 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
830 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
831 task_message_size(MESSAGE_HANDSHAKE));
832 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
833 XBT_DEBUG("Sending a HANDSHAKE to %s", remote_peer->mailbox);
837 /** @brief Send a "handshake" message to an user
838 * @param peer peer data
839 * @param mailbox mailbox where to we send the message
841 void send_handshake(peer_t peer, const char *mailbox)
843 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
844 task_message_size(MESSAGE_HANDSHAKE));
845 MSG_task_dsend(task, mailbox, task_message_free);
846 XBT_DEBUG("Sending a HANDSHAKE to %s", mailbox);
849 /** Send a "choked" message to a peer. */
850 void send_choked(peer_t peer, const char *mailbox)
852 XBT_DEBUG("Sending a CHOKE to %s", mailbox);
853 msg_task_t task = task_message_new(MESSAGE_CHOKE, peer->hostname, peer->mailbox, peer->id,
854 task_message_size(MESSAGE_CHOKE));
855 MSG_task_dsend(task, mailbox, task_message_free);
858 /** Send a "unchoked" message to a peer */
859 void send_unchoked(peer_t peer, const char *mailbox)
861 XBT_DEBUG("Sending a UNCHOKE to %s", mailbox);
862 msg_task_t task = task_message_new(MESSAGE_UNCHOKE, peer->hostname, peer->mailbox, peer->id,
863 task_message_size(MESSAGE_UNCHOKE));
864 MSG_task_dsend(task, mailbox, task_message_free);
867 /** Send a "HAVE" message to all peers we are connected to */
868 void send_have(peer_t peer, int piece)
870 XBT_DEBUG("Sending HAVE message to all my peers");
871 connection_t remote_peer;
872 xbt_dict_cursor_t cursor = NULL;
874 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
875 msg_task_t task = task_message_index_new(MESSAGE_HAVE, peer->hostname, peer->mailbox, peer->id, piece,
876 task_message_size(MESSAGE_HAVE));
877 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
881 /** @brief Send a bitfield message to all the peers the peer has.
882 * @param peer peer data
884 void send_bitfield(peer_t peer, const char *mailbox)
886 XBT_DEBUG("Sending a BITFIELD to %s", mailbox);
887 msg_task_t task = task_message_bitfield_new(peer->hostname, peer->mailbox, peer->id, peer->bitfield, FILE_PIECES);
888 MSG_task_dsend(task, mailbox, task_message_free);
891 /** Send a "request" message to a pair, containing a request for a piece */
892 void send_request(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
894 XBT_DEBUG("Sending a REQUEST to %s for piece %d (%d,%d)", mailbox, piece, block_index, block_length);
895 msg_task_t task = task_message_request_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length);
896 MSG_task_dsend(task, mailbox, task_message_free);
899 /** Send a "piece" message to a pair, containing a piece of the file */
900 void send_piece(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
902 XBT_DEBUG("Sending the PIECE %d (%d,%d) to %s", piece, block_index, block_length, mailbox);
903 xbt_assert(piece >= 0, "Tried to send a piece that doesn't exist.");
904 xbt_assert((peer->bitfield[piece] == '1'), "Tried to send a piece that we doesn't have.");
905 msg_task_t task = task_message_piece_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length,
907 MSG_task_dsend(task, mailbox, task_message_free);