1 /* Copyright (c) 2012-2016. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include "connection.h"
11 #include <simgrid/msg.h>
12 #include <xbt/RngStream.h>
15 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_peers, "Messages specific for the peers");
17 //TODO: Let users change this
19 * File transfered data
20 * For the test, default values are :
21 * File size: 10 pieces * 5 blocks/piece * 16384 bytes/block = 819200 bytes
24 #define FILE_PIECES 10
25 #define PIECES_BLOCKS 5
26 #define BLOCK_SIZE 16384
27 #define ENABLE_END_GAME_MODE 1
29 /** Number of blocks asked by each request */
30 #define BLOCKS_REQUESTED 2
32 static const unsigned long int FILE_SIZE = FILE_PIECES * PIECES_BLOCKS * BLOCK_SIZE;
34 #define SLEEP_DURATION 1
36 /** Peer main function */
37 int peer(int argc, char *argv[])
41 xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
44 peer_init(&peer, xbt_str_parse_int(argv[1],"Invalid ID: %s"), 1);
46 peer_init(&peer, xbt_str_parse_int(argv[1],"Invalid ID: %s"), 0);
49 double deadline = xbt_str_parse_double(argv[2],"Invalid deadline: %s");
50 xbt_assert(deadline > 0, "Wrong deadline supplied");
51 XBT_INFO("Hi, I'm joining the network with id %d", peer.id);
52 //Getting peer data from the tracker.
53 if (get_peers_data(&peer)) {
54 XBT_DEBUG("Got %d peers from the tracker", xbt_dict_length(peer.peers));
55 XBT_DEBUG("Here is my current status: %s", peer.bitfield);
56 peer.begin_receive_time = MSG_get_clock();
57 MSG_mailbox_set_async(peer.mailbox);
58 if (has_finished(peer.bitfield)) {
59 peer.pieces = FILE_PIECES;
60 send_handshake_all(&peer);
61 seed_loop(&peer, deadline);
63 leech_loop(&peer, deadline);
64 seed_loop(&peer, deadline);
67 XBT_INFO("Couldn't contact the tracker.");
70 XBT_INFO("Here is my current status: %s", peer.bitfield);
71 if (peer.comm_received) {
72 MSG_comm_destroy(peer.comm_received);
79 /** @brief Peer main loop when it is leeching.
80 * @param peer peer data
81 * @param deadline time at which the peer has to leave
83 void leech_loop(peer_t peer, double deadline)
85 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
86 XBT_DEBUG("Start downloading.");
88 * Send a "handshake" message to all the peers it got
89 * (since it couldn't have gotten more than 50 peers)
91 send_handshake_all(peer);
92 XBT_DEBUG("Starting main leech loop");
94 while (MSG_get_clock() < deadline && peer->pieces < FILE_PIECES) {
95 if (peer->comm_received == NULL) {
96 peer->task_received = NULL;
97 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
99 if (MSG_comm_test(peer->comm_received)) {
100 msg_error_t status = MSG_comm_get_status(peer->comm_received);
101 MSG_comm_destroy(peer->comm_received);
102 peer->comm_received = NULL;
103 if (status == MSG_OK) {
104 handle_message(peer, peer->task_received);
107 //We don't execute the choke algorithm if we don't already have a piece
108 if (MSG_get_clock() >= next_choked_update && peer->pieces > 0) {
109 update_choked_peers(peer);
110 next_choked_update += UPDATE_CHOKED_INTERVAL;
112 MSG_process_sleep(SLEEP_DURATION);
116 if (peer->pieces == FILE_PIECES)
117 XBT_DEBUG("%d becomes a seeder", peer->id);
121 /** @brief Peer main loop when it is seeding
122 * @param peer peer data
123 * @param deadline time when the peer will leave
125 void seed_loop(peer_t peer, double deadline)
127 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
128 XBT_DEBUG("Start seeding.");
129 //start the main seed loop
130 while (MSG_get_clock() < deadline) {
131 if (peer->comm_received == NULL) {
132 peer->task_received = NULL;
133 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
135 if (MSG_comm_test(peer->comm_received)) {
136 msg_error_t status = MSG_comm_get_status(peer->comm_received);
137 MSG_comm_destroy(peer->comm_received);
138 peer->comm_received = NULL;
139 if (status == MSG_OK) {
140 handle_message(peer, peer->task_received);
143 if (MSG_get_clock() >= next_choked_update) {
144 update_choked_peers(peer);
145 //TODO: Change the choked peer algorithm when seeding.
146 next_choked_update += UPDATE_CHOKED_INTERVAL;
148 MSG_process_sleep(SLEEP_DURATION);
154 /** @brief Retrieves the peer list from the tracker
155 * @param peer current peer data
157 int get_peers_data(peer_t peer)
160 int send_success = 0;
161 double timeout = MSG_get_clock() + GET_PEERS_TIMEOUT;
162 //Build the task to send to the tracker
163 tracker_task_data_t data = tracker_task_data_new(MSG_host_get_name(MSG_host_self()), peer->mailbox_tracker,
164 peer->id, 0, 0, FILE_SIZE);
165 //Build the task to send.
166 msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
167 msg_task_t task_received = NULL;
168 msg_comm_t comm_received;
169 while ((send_success == 0) && MSG_get_clock() < timeout) {
170 XBT_DEBUG("Sending a peer request to the tracker.");
171 msg_error_t status = MSG_task_send_with_timeout(task_send, TRACKER_MAILBOX, GET_PEERS_TIMEOUT);
172 if (status == MSG_OK) {
176 while ((success ==0) && MSG_get_clock() < timeout) {
177 comm_received = MSG_task_irecv(&task_received, peer->mailbox_tracker);
178 msg_error_t status = MSG_comm_wait(comm_received, GET_PEERS_TIMEOUT);
179 if (status == MSG_OK) {
180 tracker_task_data_t data = MSG_task_get_data(task_received);
183 //Add the peers the tracker gave us to our peer list.
184 xbt_dynar_foreach(data->peers, i, peer_id) {
185 if (peer_id != peer->id)
186 xbt_dict_set_ext(peer->peers, (char *) &peer_id, sizeof(int), connection_new(peer_id), NULL);
189 //free the communication and the task
190 MSG_comm_destroy(comm_received);
191 tracker_task_data_free(data);
192 MSG_task_destroy(task_received);
193 comm_received = NULL;
200 /** @brief Initialize the peer data.
201 * @param peer peer data
202 * @param id id of the peer to take in the network
203 * @param seed indicates if the peer is a seed.
205 void peer_init(peer_t peer, int id, int seed)
208 snprintf(peer->mailbox,MAILBOX_SIZE-1, "%d", id);
209 snprintf(peer->mailbox_tracker,MAILBOX_SIZE-1, "tracker_%d", id);
210 peer->peers = xbt_dict_new();
211 peer->active_peers = xbt_dict_new();
212 peer->hostname = MSG_host_get_name(MSG_host_self());
214 peer->bitfield = xbt_new(char, FILE_PIECES + 1);
215 peer->bitfield_blocks = xbt_new(char, (FILE_PIECES) * (PIECES_BLOCKS) + 1);
217 memset(peer->bitfield, '1', sizeof(char) * (FILE_PIECES + 1));
218 memset(peer->bitfield_blocks, '1', sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
220 memset(peer->bitfield, '0', sizeof(char) * (FILE_PIECES + 1));
221 memset(peer->bitfield_blocks, '0', sizeof(char) * FILE_PIECES * (PIECES_BLOCKS));
224 peer->bitfield[FILE_PIECES] = '\0';
227 peer->pieces_count = xbt_new0(short, FILE_PIECES);
229 peer->current_pieces = xbt_dynar_new(sizeof(int), NULL);
231 peer->stream = (RngStream)MSG_host_get_property_value(MSG_host_self(), "stream");
232 peer->comm_received = NULL;
237 /** Destroys a poor peer object. */
238 void peer_free(peer_t peer)
241 connection_t connection;
242 xbt_dict_cursor_t cursor;
243 xbt_dict_foreach(peer->peers, cursor, key, connection) {
244 connection_free(connection);
246 xbt_dict_free(&peer->peers);
247 xbt_dict_free(&peer->active_peers);
248 xbt_dynar_free(&peer->current_pieces);
249 xbt_free(peer->pieces_count);
250 xbt_free(peer->bitfield);
251 xbt_free(peer->bitfield_blocks);
254 /** @brief Returns if a peer has finished downloading the file
255 * @param bitfield peer bitfield
257 int has_finished(char *bitfield)
259 return ((memchr(bitfield, '0', sizeof(char) * FILE_PIECES) == NULL) ? 1 : 0);
262 int nb_interested_peers(peer_t peer)
264 xbt_dict_cursor_t cursor = NULL;
266 connection_t connection;
268 xbt_dict_foreach(peer->peers, cursor, key, connection) {
269 if (connection->interested)
275 void update_active_peers_set(peer_t peer, connection_t remote_peer)
277 if ((remote_peer->interested != 0) && (remote_peer->choked_upload == 0)) {
278 //add in the active peers set
279 xbt_dict_set_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int), remote_peer, NULL);
280 } else if (xbt_dict_get_or_null_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int))) {
281 xbt_dict_remove_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int));
285 /** @brief Handle a received message sent by another peer
286 * @param peer Peer data
287 * @param task task received.
289 void handle_message(peer_t peer, msg_task_t task)
291 message_t message = MSG_task_get_data(task);
292 connection_t remote_peer;
293 remote_peer = xbt_dict_get_or_null_ext(peer->peers, (char *) &message->peer_id, sizeof(int));
294 switch (message->type) {
295 case MESSAGE_HANDSHAKE:
296 XBT_DEBUG("Received a HANDSHAKE from %s (%s)", message->mailbox, message->issuer_host_name);
297 //Check if the peer is in our connection list.
298 if (remote_peer == 0) {
299 xbt_dict_set_ext(peer->peers, (char *) &message->peer_id, sizeof(int), connection_new(message->peer_id), NULL);
300 send_handshake(peer, message->mailbox);
302 //Send our bitfield to the peer
303 send_bitfield(peer, message->mailbox);
305 case MESSAGE_BITFIELD:
306 XBT_DEBUG("Recieved a BITFIELD message from %s (%s)", message->mailbox, message->issuer_host_name);
307 //Update the pieces list
308 update_pieces_count_from_bitfield(peer, message->bitfield);
310 remote_peer->bitfield = xbt_strdup(message->bitfield);
311 xbt_assert(!remote_peer->am_interested, "Should not be interested at first");
312 if (is_interested(peer, remote_peer)) {
313 remote_peer->am_interested = 1;
314 send_interested(peer, message->mailbox);
317 case MESSAGE_INTERESTED:
318 XBT_DEBUG("Recieved an INTERESTED message from %s (%s)", message->mailbox, message->issuer_host_name);
319 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
320 //Update the interested state of the peer.
321 remote_peer->interested = 1;
322 update_active_peers_set(peer, remote_peer);
324 case MESSAGE_NOTINTERESTED:
325 XBT_DEBUG("Received a NOTINTERESTED message from %s (%s)", message->mailbox, message->issuer_host_name);
326 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
327 remote_peer->interested = 0;
328 update_active_peers_set(peer, remote_peer);
330 case MESSAGE_UNCHOKE:
331 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
332 XBT_DEBUG("Received a UNCHOKE message from %s (%s)", message->mailbox, message->issuer_host_name);
333 xbt_assert(remote_peer->choked_download, "WTF !!!");
334 remote_peer->choked_download = 0;
335 //Send requests to the peer, since it has unchoked us
336 if (remote_peer->am_interested)
337 request_new_piece_to_peer(peer, remote_peer);
340 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
341 XBT_DEBUG("Received a CHOKE message from %s (%s)", message->mailbox, message->issuer_host_name);
342 xbt_assert(!remote_peer->choked_download, "WTF !!!");
343 remote_peer->choked_download = 1;
344 remove_current_piece(peer, remote_peer, remote_peer->current_piece);
347 XBT_DEBUG("Received a HAVE message from %s (%s) of piece %d", message->mailbox, message->issuer_host_name,
349 xbt_assert(remote_peer->bitfield, "bitfield not received");
350 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
351 remote_peer->bitfield[message->index] = '1';
352 peer->pieces_count[message->index]++;
353 //If the piece is in our pieces, we tell the peer that we are interested.
354 if ((remote_peer->am_interested == 0) &&
355 peer->bitfield[message->index] == '0') {
356 remote_peer->am_interested = 1;
357 send_interested(peer, message->mailbox);
358 if (remote_peer->choked_download == 0)
359 request_new_piece_to_peer(peer, remote_peer);
362 case MESSAGE_REQUEST:
363 xbt_assert(remote_peer->interested, "WTF !!!");
365 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
366 if (remote_peer->choked_upload == 0) {
367 XBT_DEBUG("Received a REQUEST from %s (%s) for %d (%d,%d)", message->mailbox, message->issuer_host_name,
368 message->index, message->block_index, message->block_index + message->block_length);
369 if (peer->bitfield[message->index] == '1') {
370 send_piece(peer, message->mailbox, message->index, message->block_index, message->block_length);
373 XBT_DEBUG("Received a REQUEST from %s (%s) for %d but he is choked.", message->mailbox,
374 message->issuer_host_name, message->peer_id);
378 XBT_DEBUG("Received piece %d (%d,%d) from %s (%s)", message->index, message->block_index,
379 message->block_index + message->block_length, message->mailbox, message->issuer_host_name);
380 xbt_assert(!remote_peer->choked_download, "WTF !!!");
381 xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
382 "Can't received a piece if I'm not interested wihtout end-game mode!"
383 "piece (%d) bitfield(%s) remote bitfield(%s)", message->index, peer->bitfield, remote_peer->bitfield);
384 xbt_assert(remote_peer->choked_download != 1, "Can't received a piece if I'm choked !");
385 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
386 //TODO: Execute à computation.
387 if (peer->bitfield[message->index] == '0') {
388 update_bitfield_blocks(peer, message->index, message->block_index, message->block_length);
389 if (piece_complete(peer, message->index)) {
390 //Removing the piece from our piece list
391 remove_current_piece(peer, remote_peer, message->index);
392 //Setting the fact that we have the piece
393 peer->bitfield[message->index] = '1';
395 XBT_DEBUG("My status is now %s", peer->bitfield);
396 //Sending the information to all the peers we are connected to
397 send_have(peer, message->index);
398 //sending UNINTERSTED to peers that doesn't have what we want.
399 update_interested_after_receive(peer);
400 } else { // piece not completed
401 send_request_to_peer(peer, remote_peer, message->index); // ask for the next block
404 XBT_DEBUG("However, we already have it");
405 xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
406 request_new_piece_to_peer(peer, remote_peer);
410 XBT_DEBUG("The received CANCEL from %s (%s)", message->mailbox, message->issuer_host_name);
415 //Update the peer speed.
417 connection_add_speed_value(remote_peer, 1.0 / (MSG_get_clock() - peer->begin_receive_time));
419 peer->begin_receive_time = MSG_get_clock();
421 task_message_free(task);
424 /** Selects the appropriate piece to download and requests it to the remote_peer */
425 void request_new_piece_to_peer(peer_t peer, connection_t remote_peer)
427 int piece = select_piece_to_download(peer, remote_peer);
429 xbt_dynar_push_as(peer->current_pieces, int, piece);
430 send_request_to_peer(peer, remote_peer, piece);
434 /** remove current_piece from the list of currently downloaded pieces. */
435 void remove_current_piece(peer_t peer, connection_t remote_peer, int current_piece)
437 int piece_index = xbt_dynar_search_or_negative(peer->current_pieces, ¤t_piece);
438 if (piece_index != -1)
439 xbt_dynar_remove_at(peer->current_pieces, piece_index, NULL);
440 remote_peer->current_piece = -1;
443 /** @brief Updates the list of who has a piece from a bitfield
444 * @param peer peer we want to update the list
445 * @param bitfield bitfield
447 void update_pieces_count_from_bitfield(peer_t peer, char *bitfield)
450 for (i = 0; i < FILE_PIECES; i++) {
451 if (bitfield[i] == '1') {
452 peer->pieces_count[i]++;
457 /** @brief Return the piece to be downloaded
458 * There are two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
459 * If a piece is partially downloaded, this piece will be selected prioritarily
460 * If the peer has strictly less than 4 pieces, he chooses a piece at random.
461 * If the peer has more than pieces, he downloads the pieces that are the less replicated (rarest policy).
462 * If all pieces have been downloaded or requested, we select a random requested piece (endgame mode).
463 * @param peer: local peer
464 * @param remote_peer: information about the connection
465 * @return the piece to download if possible. -1 otherwise
467 int select_piece_to_download(peer_t peer, connection_t remote_peer)
471 piece = partially_downloaded_piece(peer, remote_peer);
472 // strict priority policy
477 if (xbt_dynar_length(peer->current_pieces) >= (FILE_PIECES - peer->pieces) &&
478 (is_interested(peer, remote_peer) != 0)) {
479 if(ENABLE_END_GAME_MODE == 0)
482 int nb_interesting_pieces = 0;
483 int current_index = 0;
484 // compute the number of interesting pieces
485 for (i = 0; i < FILE_PIECES; i++) {
486 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1') {
487 nb_interesting_pieces++;
490 xbt_assert(nb_interesting_pieces != 0, "WTF !!!");
491 // get a random interesting piece
492 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
493 for (i = 0; i < FILE_PIECES; i++) {
494 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1') {
495 if (random_piece_index == current_index) {
502 xbt_assert(piece != -1, "WTF !!!");
505 // Random first policy
506 if (peer->pieces < 4 && (is_interested_and_free(peer, remote_peer) != 0)) {
508 int nb_interesting_pieces = 0;
509 int current_index = 0;
510 // compute the number of interesting pieces
511 for (i = 0; i < FILE_PIECES; i++) {
512 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1' &&
513 (in_current_pieces(peer, i) == 0)) {
514 nb_interesting_pieces++;
517 xbt_assert(nb_interesting_pieces != 0, "WTF !!!");
518 // get a random interesting piece
519 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
520 for (i = 0; i < FILE_PIECES; i++) {
521 if (peer->bitfield[i] == '0' && remote_peer->bitfield[i] == '1' &&
522 (in_current_pieces(peer, i) == 0)) {
523 if (random_piece_index == current_index) {
530 xbt_assert(piece != -1, "WTF !!!");
532 } else { // Rarest first policy
534 short min = SHRT_MAX;
535 int nb_min_pieces = 0;
536 int current_index = 0;
537 // compute the smallest number of copies of available pieces
538 for (i = 0; i < FILE_PIECES; i++) {
539 if (peer->pieces_count[i] < min && peer->bitfield[i] == '0' &&
540 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i) == 0))
541 min = peer->pieces_count[i];
543 xbt_assert(min != SHRT_MAX ||
544 (is_interested_and_free(peer, remote_peer) ==0), "WTF !!!");
545 // compute the number of rarest pieces
546 for (i = 0; i < FILE_PIECES; i++) {
547 if (peer->pieces_count[i] == min && peer->bitfield[i] == '0' &&
548 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i) ==0))
551 xbt_assert(nb_min_pieces != 0 ||
552 (is_interested_and_free(peer, remote_peer)==0), "WTF !!!");
553 // get a random rarest piece
554 int random_rarest_index = RngStream_RandInt(peer->stream, 0, nb_min_pieces - 1);
555 for (i = 0; i < FILE_PIECES; i++) {
556 if (peer->pieces_count[i] == min && peer->bitfield[i] == '0' &&
557 remote_peer->bitfield[i] == '1' && (in_current_pieces(peer, i)==0)) {
558 if (random_rarest_index == current_index) {
565 xbt_assert(piece != -1 || (is_interested_and_free(peer, remote_peer) == 0), "WTF !!!");
570 /** @brief Update the list of current choked and unchoked peers, using the choke algorithm
571 * @param peer the current peer
573 void update_choked_peers(peer_t peer)
575 if (nb_interested_peers(peer) == 0)
577 XBT_DEBUG("(%d) update_choked peers %d active peers", peer->id, xbt_dict_size(peer->active_peers));
578 //update the current round
579 peer->round = (peer->round + 1) % 3;
581 char *key_choked=NULL;
582 connection_t peer_choosed = NULL;
583 connection_t peer_choked = NULL;
584 //remove a peer from the list
585 xbt_dict_cursor_t cursor = NULL;
586 xbt_dict_cursor_first(peer->active_peers, &cursor);
587 if (xbt_dict_length(peer->active_peers) > 0) {
588 key_choked = xbt_dict_cursor_get_key(cursor);
589 peer_choked = xbt_dict_cursor_get_data(cursor);
591 xbt_dict_cursor_free(&cursor);
593 /**If we are currently seeding, we unchoke the peer which has been unchoked the last time.*/
594 if (peer->pieces == FILE_PIECES) {
595 connection_t connection;
596 double unchoke_time = MSG_get_clock() + 1;
598 xbt_dict_foreach(peer->peers, cursor, key, connection) {
599 if (connection->last_unchoke < unchoke_time &&
600 (connection->interested != 0) && (connection->choked_upload != 0)) {
601 unchoke_time = connection->last_unchoke;
602 peer_choosed = connection;
606 //Random optimistic unchoking
607 if (peer->round == 0) {
610 //We choose a random peer to unchoke.
611 int id_chosen = RngStream_RandInt(peer->stream, 0, xbt_dict_length(peer->peers) - 1);
613 connection_t connection;
614 xbt_dict_foreach(peer->peers, cursor, key, connection) {
615 if (i == id_chosen) {
616 peer_choosed = connection;
621 xbt_dict_cursor_free(&cursor);
622 if ((peer_choosed->interested == 0) ||
623 (peer_choosed->choked_upload == 0)) {
627 } while (peer_choosed == NULL && j < MAXIMUM_PAIRS);
629 //Use the "fastest download" policy.
630 connection_t connection;
631 double fastest_speed = 0.0;
632 xbt_dict_foreach(peer->peers, cursor, key, connection) {
633 if (connection->peer_speed > fastest_speed &&
634 (connection->choked_upload != 0) && (connection->interested != 0)) {
635 peer_choosed = connection;
636 fastest_speed = connection->peer_speed;
642 if (peer_choosed != NULL)
643 XBT_DEBUG("(%d) update_choked peers unchoked (%d) ; int (%d) ; choked (%d) ",
644 peer->id, peer_choosed->id, peer_choosed->interested, peer_choosed->choked_upload);
646 if (peer_choked != peer_choosed) {
647 if (peer_choked != NULL) {
648 xbt_assert((!peer_choked->choked_upload), "Tries to choked a choked peer");
649 peer_choked->choked_upload = 1;
650 xbt_assert((*((int *) key_choked) == peer_choked->id), "WTF !!!");
651 update_active_peers_set(peer, peer_choked);
652 XBT_DEBUG("(%d) Sending a CHOKE to %d", peer->id, peer_choked->id);
653 send_choked(peer, peer_choked->mailbox);
655 if (peer_choosed != NULL) {
656 xbt_assert((peer_choosed->choked_upload), "Tries to unchoked an unchoked peer");
657 peer_choosed->choked_upload = 0;
658 xbt_dict_set_ext(peer->active_peers, (char *) &peer_choosed->id, sizeof(int), peer_choosed, NULL);
659 peer_choosed->last_unchoke = MSG_get_clock();
660 XBT_DEBUG("(%d) Sending a UNCHOKE to %d", peer->id, peer_choosed->id);
661 update_active_peers_set(peer, peer_choosed);
662 send_unchoked(peer, peer_choosed->mailbox);
667 /** @brief Update "interested" state of peers: send "not interested" to peers that don't have any more pieces we want.
668 * @param peer our peer data
670 void update_interested_after_receive(peer_t peer)
673 xbt_dict_cursor_t cursor;
674 connection_t connection;
676 xbt_dict_foreach(peer->peers, cursor, key, connection) {
678 if (connection->am_interested != 0) {
679 xbt_assert(connection->bitfield, "Bitfield not received");
680 //Check if the peer still has a piece we want.
682 for (i = 0; i < FILE_PIECES; i++) {
683 if (connection->bitfield[i] == '1' && peer->bitfield[i] == '0') {
688 if (!interested) { //no more piece to download from connection
689 connection->am_interested = 0;
690 send_notinterested(peer, connection->mailbox);
696 void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length)
699 xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
700 xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.", block_index);
701 for (i = block_index; i < (block_index + block_length); i++) {
702 peer->bitfield_blocks[index * PIECES_BLOCKS + i] = '1';
706 /** Returns if a peer has completed the download of a piece */
707 int piece_complete(peer_t peer, int index)
710 for (i = 0; i < PIECES_BLOCKS; i++) {
711 if (peer->bitfield_blocks[index * PIECES_BLOCKS + i] == '0') {
718 /** Returns the first block that a peer doesn't have in a piece. If the peer has all blocks of the piece, returns -1. */
719 int get_first_block(peer_t peer, int piece)
722 for (i = 0; i < PIECES_BLOCKS; i++) {
723 if (peer->bitfield_blocks[piece * PIECES_BLOCKS + i] == '0') {
730 /** Indicates if the remote peer has a piece not stored by the local peer */
731 int is_interested(peer_t peer, connection_t remote_peer)
733 xbt_assert(remote_peer->bitfield, "Bitfield not received");
734 for (int i = 0; i < FILE_PIECES; i++) {
735 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0') {
742 /** Indicates if the remote peer has a piece not stored by the local peer nor requested by the local peer */
743 int is_interested_and_free(peer_t peer, connection_t remote_peer)
745 xbt_assert(remote_peer->bitfield, "Bitfield not received");
746 for (int i = 0; i < FILE_PIECES; i++) {
747 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0' &&
748 (in_current_pieces(peer, i) == 0)) {
755 /** Returns a piece that is partially downloaded and stored by the remote peer if any -1 otherwise. */
756 int partially_downloaded_piece(peer_t peer, connection_t remote_peer)
758 xbt_assert(remote_peer->bitfield, "Bitfield not received");
759 for (int i = 0; i < FILE_PIECES; i++) {
760 if (remote_peer->bitfield[i] == '1' && peer->bitfield[i] == '0' &&
761 (in_current_pieces(peer, i) == 0)) {
762 if (get_first_block(peer, i) > 0)
769 /** @brief Send request messages to a peer that have unchoked us
771 * @param remote_peer peer data to the peer we want to send the request
773 void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece)
775 remote_peer->current_piece = piece;
776 xbt_assert(remote_peer->bitfield, "bitfield not received");
777 xbt_assert(remote_peer->bitfield[piece] == '1', "WTF !!!");
778 int block_index = get_first_block(peer, piece);
779 if (block_index != -1) {
780 int block_length = PIECES_BLOCKS - block_index;
781 block_length = MIN(BLOCKS_REQUESTED, block_length);
782 send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
786 /** Indicates if a piece is currently being downloaded by the peer. */
787 int in_current_pieces(peer_t peer, int piece)
789 return xbt_dynar_member(peer->current_pieces, &piece);
792 /***********************************************************
794 * Low level message functions
796 ***********************************************************/
798 /** @brief Send a "interested" message to a peer
799 * @param peer peer data
800 * @param mailbox destination mailbox
802 void send_interested(peer_t peer, const char *mailbox)
804 msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id,
805 task_message_size(MESSAGE_INTERESTED));
806 MSG_task_dsend(task, mailbox, task_message_free);
807 XBT_DEBUG("Sending INTERESTED to %s", mailbox);
810 /** @brief Send a "not interested" message to a peer
811 * @param peer peer data
812 * @param mailbox destination mailbox
814 void send_notinterested(peer_t peer, const char *mailbox)
816 msg_task_t task = task_message_new(MESSAGE_NOTINTERESTED, peer->hostname, peer->mailbox, peer->id,
817 task_message_size(MESSAGE_NOTINTERESTED));
818 MSG_task_dsend(task, mailbox, task_message_free);
819 XBT_DEBUG("Sending NOTINTERESTED to %s", mailbox);
822 /** @brief Send a handshake message to all the peers the peer has.
823 * @param peer peer data
825 void send_handshake_all(peer_t peer)
827 connection_t remote_peer;
828 xbt_dict_cursor_t cursor = NULL;
830 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
831 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
832 task_message_size(MESSAGE_HANDSHAKE));
833 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
834 XBT_DEBUG("Sending a HANDSHAKE to %s", remote_peer->mailbox);
838 /** @brief Send a "handshake" message to an user
839 * @param peer peer data
840 * @param mailbox mailbox where to we send the message
842 void send_handshake(peer_t peer, const char *mailbox)
844 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
845 task_message_size(MESSAGE_HANDSHAKE));
846 MSG_task_dsend(task, mailbox, task_message_free);
847 XBT_DEBUG("Sending a HANDSHAKE to %s", mailbox);
850 /** Send a "choked" message to a peer. */
851 void send_choked(peer_t peer, const char *mailbox)
853 XBT_DEBUG("Sending a CHOKE to %s", mailbox);
854 msg_task_t task = task_message_new(MESSAGE_CHOKE, peer->hostname, peer->mailbox, peer->id,
855 task_message_size(MESSAGE_CHOKE));
856 MSG_task_dsend(task, mailbox, task_message_free);
859 /** Send a "unchoked" message to a peer */
860 void send_unchoked(peer_t peer, const char *mailbox)
862 XBT_DEBUG("Sending a UNCHOKE to %s", mailbox);
863 msg_task_t task = task_message_new(MESSAGE_UNCHOKE, peer->hostname, peer->mailbox, peer->id,
864 task_message_size(MESSAGE_UNCHOKE));
865 MSG_task_dsend(task, mailbox, task_message_free);
868 /** Send a "HAVE" message to all peers we are connected to */
869 void send_have(peer_t peer, int piece)
871 XBT_DEBUG("Sending HAVE message to all my peers");
872 connection_t remote_peer;
873 xbt_dict_cursor_t cursor = NULL;
875 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
876 msg_task_t task = task_message_index_new(MESSAGE_HAVE, peer->hostname, peer->mailbox, peer->id, piece,
877 task_message_size(MESSAGE_HAVE));
878 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
882 /** @brief Send a bitfield message to all the peers the peer has.
883 * @param peer peer data
885 void send_bitfield(peer_t peer, const char *mailbox)
887 XBT_DEBUG("Sending a BITFIELD to %s", mailbox);
888 msg_task_t task = task_message_bitfield_new(peer->hostname, peer->mailbox, peer->id, peer->bitfield, FILE_PIECES);
889 MSG_task_dsend(task, mailbox, task_message_free);
892 /** Send a "request" message to a pair, containing a request for a piece */
893 void send_request(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
895 XBT_DEBUG("Sending a REQUEST to %s for piece %d (%d,%d)", mailbox, piece, block_index, block_length);
896 msg_task_t task = task_message_request_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length);
897 MSG_task_dsend(task, mailbox, task_message_free);
900 /** Send a "piece" message to a pair, containing a piece of the file */
901 void send_piece(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
903 XBT_DEBUG("Sending the PIECE %d (%d,%d) to %s", piece, block_index, block_length, mailbox);
904 xbt_assert(piece >= 0, "Tried to send a piece that doesn't exist.");
905 xbt_assert((peer->bitfield[piece] == '1'), "Tried to send a piece that we doesn't have.");
906 msg_task_t task = task_message_piece_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length,
908 MSG_task_dsend(task, mailbox, task_message_free);