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. */
7 #include "connection.h"
11 #include <simgrid/msg.h>
12 #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 10UL
21 #define PIECES_BLOCKS 5UL
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 int count_pieces(unsigned int bitfield)
34 unsigned int n = bitfield;
42 int peer_has_not_piece(peer_t peer, unsigned int piece)
44 return !(peer->bitfield & 1U << piece);
47 /** Check that a piece is not currently being download by the peer. */
48 int peer_is_not_downloading_piece(peer_t peer, unsigned int piece)
50 return !(peer->current_pieces & 1U << piece);
53 void get_status(char** status, unsigned int bitfield)
55 for (int i = FILE_PIECES - 1; i >= 0; i--)
56 (*status)[i] = (bitfield & (1U << i)) ? '1' : '0';
57 (*status)[FILE_PIECES] = '\0';
60 /** Peer main function */
61 int peer(int argc, char* argv[])
64 xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
67 peer_t peer = peer_init(xbt_str_parse_int(argv[1], "Invalid ID: %s"), argc == 4 ? 1 : 0);
70 double deadline = xbt_str_parse_double(argv[2], "Invalid deadline: %s");
71 xbt_assert(deadline > 0, "Wrong deadline supplied");
73 char* status = xbt_malloc0(FILE_PIECES + 1);
74 get_status(&status, peer->bitfield);
75 XBT_INFO("Hi, I'm joining the network with id %d", peer->id);
76 // Getting peer data from the tracker.
77 if (get_peers_data(peer)) {
78 XBT_DEBUG("Got %d peers from the tracker. Current status is: %s", xbt_dict_length(peer->peers), status);
79 peer->begin_receive_time = MSG_get_clock();
80 MSG_mailbox_set_async(peer->mailbox);
81 if (has_finished(peer->bitfield)) {
82 send_handshake_all(peer);
84 leech_loop(peer, deadline);
86 seed_loop(peer, deadline);
88 XBT_INFO("Couldn't contact the tracker.");
91 get_status(&status, peer->bitfield);
92 XBT_INFO("Here is my current status: %s", status);
93 if (peer->comm_received) {
94 MSG_comm_destroy(peer->comm_received);
102 /** @brief Peer main loop when it is leeching.
103 * @param peer peer data
104 * @param deadline time at which the peer has to leave
106 void leech_loop(peer_t peer, double deadline)
108 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
109 XBT_DEBUG("Start downloading.");
111 /* Send a "handshake" message to all the peers it got (since it couldn't have gotten more than 50 peers) */
112 send_handshake_all(peer);
113 XBT_DEBUG("Starting main leech loop");
115 while (MSG_get_clock() < deadline && count_pieces(peer->bitfield) < FILE_PIECES) {
116 if (peer->comm_received == NULL) {
117 peer->task_received = NULL;
118 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
120 if (MSG_comm_test(peer->comm_received)) {
121 msg_error_t status = MSG_comm_get_status(peer->comm_received);
122 MSG_comm_destroy(peer->comm_received);
123 peer->comm_received = NULL;
124 if (status == MSG_OK) {
125 handle_message(peer, peer->task_received);
128 // We don't execute the choke algorithm if we don't already have a piece
129 if (MSG_get_clock() >= next_choked_update && count_pieces(peer->bitfield) > 0) {
130 update_choked_peers(peer);
131 next_choked_update += UPDATE_CHOKED_INTERVAL;
133 MSG_process_sleep(SLEEP_DURATION);
137 if (has_finished(peer->bitfield))
138 XBT_DEBUG("%d becomes a seeder", peer->id);
141 /** @brief Peer main loop when it is seeding
142 * @param peer peer data
143 * @param deadline time when the peer will leave
145 void seed_loop(peer_t peer, double deadline)
147 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
148 XBT_DEBUG("Start seeding.");
149 // start the main seed loop
150 while (MSG_get_clock() < deadline) {
151 if (peer->comm_received == NULL) {
152 peer->task_received = NULL;
153 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
155 if (MSG_comm_test(peer->comm_received)) {
156 msg_error_t status = MSG_comm_get_status(peer->comm_received);
157 MSG_comm_destroy(peer->comm_received);
158 peer->comm_received = NULL;
159 if (status == MSG_OK) {
160 handle_message(peer, peer->task_received);
163 if (MSG_get_clock() >= next_choked_update) {
164 update_choked_peers(peer);
165 // TODO: Change the choked peer algorithm when seeding.
166 next_choked_update += UPDATE_CHOKED_INTERVAL;
168 MSG_process_sleep(SLEEP_DURATION);
174 /** @brief Retrieves the peer list from the tracker
175 * @param peer current peer data
177 int get_peers_data(peer_t peer)
180 double timeout = MSG_get_clock() + GET_PEERS_TIMEOUT;
182 // Build the task to send to the tracker
183 tracker_task_data_t data =
184 tracker_task_data_new(MSG_host_get_name(MSG_host_self()), peer->mailbox_tracker, peer->id, 0, 0, FILE_SIZE);
185 msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
186 while ((success == 0) && MSG_get_clock() < timeout) {
187 XBT_DEBUG("Sending a peer request to the tracker.");
188 msg_error_t status = MSG_task_send_with_timeout(task_send, TRACKER_MAILBOX, GET_PEERS_TIMEOUT);
189 if (status == MSG_OK) {
195 msg_task_t task_received = NULL;
196 while ((success == 0) && MSG_get_clock() < timeout) {
197 msg_comm_t comm_received = MSG_task_irecv(&task_received, peer->mailbox_tracker);
198 msg_error_t status = MSG_comm_wait(comm_received, GET_PEERS_TIMEOUT);
199 if (status == MSG_OK) {
200 tracker_task_data_t data = MSG_task_get_data(task_received);
203 // Add the peers the tracker gave us to our peer list.
204 xbt_dynar_foreach (data->peers, i, peer_id) {
205 if (peer_id != peer->id)
206 xbt_dict_set_ext(peer->peers, (char*)&peer_id, sizeof(int), connection_new(peer_id), NULL);
209 // free the communication and the task
210 MSG_comm_destroy(comm_received);
211 tracker_task_data_free(data);
212 MSG_task_destroy(task_received);
219 /** @brief Initialize the peer data.
220 * @param peer peer data
221 * @param id id of the peer to take in the network
222 * @param seed indicates if the peer is a seed.
224 peer_t peer_init(int id, int seed)
226 peer_t peer = xbt_new(s_peer_t, 1);
228 peer->hostname = MSG_host_get_name(MSG_host_self());
230 snprintf(peer->mailbox, MAILBOX_SIZE - 1, "%d", id);
231 snprintf(peer->mailbox_tracker, MAILBOX_SIZE - 1, "tracker_%d", id);
232 peer->peers = xbt_dict_new_homogeneous(NULL);
233 peer->active_peers = xbt_dict_new_homogeneous(NULL);
236 peer->bitfield = (1U << FILE_PIECES) - 1U;
237 peer->bitfield_blocks = (1ULL << (FILE_PIECES * PIECES_BLOCKS)) - 1ULL;
240 peer->bitfield_blocks = 0;
243 peer->current_pieces = 0;
245 peer->pieces_count = xbt_new0(short, FILE_PIECES);
247 peer->stream = (RngStream)MSG_host_get_data(MSG_host_self());
248 peer->comm_received = NULL;
255 /** Destroys a poor peer object. */
256 void peer_free(peer_t peer)
259 connection_t connection;
260 xbt_dict_cursor_t cursor;
261 xbt_dict_foreach (peer->peers, cursor, key, connection) {
262 connection_free(connection);
264 xbt_dict_free(&peer->peers);
265 xbt_dict_free(&peer->active_peers);
266 xbt_free(peer->pieces_count);
270 /** @brief Returns if a peer has finished downloading the file
271 * @param bitfield peer bitfield
273 int has_finished(unsigned int bitfield)
275 return bitfield == (1U << FILE_PIECES) - 1U;
278 int nb_interested_peers(peer_t peer)
280 xbt_dict_cursor_t cursor = NULL;
282 connection_t connection;
284 xbt_dict_foreach (peer->peers, cursor, key, connection) {
285 if (connection->interested)
291 void update_active_peers_set(peer_t peer, connection_t remote_peer)
293 if ((remote_peer->interested != 0) && (remote_peer->choked_upload == 0)) {
294 // add in the active peers set
295 xbt_dict_set_ext(peer->active_peers, (char*)&remote_peer->id, sizeof(int), remote_peer, NULL);
296 } else if (xbt_dict_get_or_null_ext(peer->active_peers, (char*)&remote_peer->id, sizeof(int))) {
297 xbt_dict_remove_ext(peer->active_peers, (char*)&remote_peer->id, sizeof(int));
301 /** @brief Handle a received message sent by another peer
302 * @param peer Peer data
303 * @param task task received.
305 void handle_message(peer_t peer, msg_task_t task)
307 const char* type_names[10] = {"HANDSHAKE", "CHOKE", "UNCHOKE", "INTERESTED", "NOTINTERESTED",
308 "HAVE", "BITFIELD", "REQUEST", "PIECE", "CANCEL"};
309 message_t message = MSG_task_get_data(task);
310 XBT_DEBUG("Received a %s message from %s (%s)", type_names[message->type], message->mailbox,
311 message->issuer_host_name);
313 connection_t remote_peer;
314 remote_peer = xbt_dict_get_or_null_ext(peer->peers, (char*)&message->peer_id, sizeof(int));
316 switch (message->type) {
317 case MESSAGE_HANDSHAKE:
318 // Check if the peer is in our connection list.
319 if (remote_peer == 0) {
320 xbt_dict_set_ext(peer->peers, (char*)&message->peer_id, sizeof(int), connection_new(message->peer_id), NULL);
321 send_handshake(peer, message->mailbox);
323 // Send our bitfield to the peer
324 send_bitfield(peer, message->mailbox);
326 case MESSAGE_BITFIELD:
327 // Update the pieces list
328 update_pieces_count_from_bitfield(peer, message->bitfield);
329 // Store the bitfield
330 remote_peer->bitfield = message->bitfield;
331 xbt_assert(!remote_peer->am_interested, "Should not be interested at first");
332 if (is_interested(peer, remote_peer)) {
333 remote_peer->am_interested = 1;
334 send_interested(peer, message->mailbox);
337 case MESSAGE_INTERESTED:
338 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
339 // Update the interested state of the peer.
340 remote_peer->interested = 1;
341 update_active_peers_set(peer, remote_peer);
343 case MESSAGE_NOTINTERESTED:
344 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
345 remote_peer->interested = 0;
346 update_active_peers_set(peer, remote_peer);
348 case MESSAGE_UNCHOKE:
349 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
350 xbt_assert(remote_peer->choked_download);
351 remote_peer->choked_download = 0;
352 // Send requests to the peer, since it has unchoked us
353 if (remote_peer->am_interested)
354 request_new_piece_to_peer(peer, remote_peer);
357 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
358 xbt_assert(!remote_peer->choked_download);
359 remote_peer->choked_download = 1;
360 if (remote_peer->current_piece != -1)
361 remove_current_piece(peer, remote_peer, remote_peer->current_piece);
364 XBT_DEBUG("\t for piece %d", message->index);
365 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
366 remote_peer->bitfield = remote_peer->bitfield | (1U << message->index);
367 peer->pieces_count[message->index]++;
368 // If the piece is in our pieces, we tell the peer that we are interested.
369 if ((remote_peer->am_interested == 0) && peer_has_not_piece(peer, message->index)) {
370 remote_peer->am_interested = 1;
371 send_interested(peer, message->mailbox);
372 if (remote_peer->choked_download == 0)
373 request_new_piece_to_peer(peer, remote_peer);
376 case MESSAGE_REQUEST:
377 xbt_assert(remote_peer->interested);
378 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
379 if (remote_peer->choked_upload == 0) {
380 XBT_DEBUG("\t for piece %d (%d,%d)", message->index, message->block_index,
381 message->block_index + message->block_length);
382 if (!peer_has_not_piece(peer, message->index)) {
383 send_piece(peer, message->mailbox, message->index, message->block_index, message->block_length);
386 XBT_DEBUG("\t for piece %d but he is choked.", message->peer_id);
390 XBT_DEBUG(" \t for piece %d (%d,%d)", message->index, message->block_index,
391 message->block_index + message->block_length);
392 xbt_assert(!remote_peer->choked_download);
393 xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
394 "Can't received a piece if I'm not interested wihtout end-game mode!"
395 "piece (%d) bitfield(%u) remote bitfield(%u)",
396 message->index, peer->bitfield, remote_peer->bitfield);
397 xbt_assert(remote_peer->choked_download != 1, "Can't received a piece if I'm choked !");
398 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
399 // TODO: Execute à computation.
400 if (peer_has_not_piece(peer, message->index)) {
401 update_bitfield_blocks(peer, message->index, message->block_index, message->block_length);
402 if (piece_complete(peer, message->index)) {
403 // Removing the piece from our piece list
404 remove_current_piece(peer, remote_peer, message->index);
405 // Setting the fact that we have the piece
406 peer->bitfield = peer->bitfield | (1U << message->index);
407 char* status = xbt_malloc0(FILE_PIECES + 1);
408 get_status(&status, peer->bitfield);
409 XBT_DEBUG("My status is now %s", status);
411 // Sending the information to all the peers we are connected to
412 send_have(peer, message->index);
413 // sending UNINTERESTED to peers that do not have what we want.
414 update_interested_after_receive(peer);
415 } else { // piece not completed
416 send_request_to_peer(peer, remote_peer, message->index); // ask for the next block
419 XBT_DEBUG("However, we already have it");
420 xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
421 request_new_piece_to_peer(peer, remote_peer);
429 // Update the peer speed.
431 connection_add_speed_value(remote_peer, 1.0 / (MSG_get_clock() - peer->begin_receive_time));
433 peer->begin_receive_time = MSG_get_clock();
435 task_message_free(task);
438 /** Selects the appropriate piece to download and requests it to the remote_peer */
439 void request_new_piece_to_peer(peer_t peer, connection_t remote_peer)
441 int piece = select_piece_to_download(peer, remote_peer);
443 peer->current_pieces |= (1U << (unsigned int)piece);
444 send_request_to_peer(peer, remote_peer, piece);
448 /** remove current_piece from the list of currently downloaded pieces. */
449 void remove_current_piece(peer_t peer, connection_t remote_peer, unsigned int current_piece)
451 peer->current_pieces &= ~(1U << current_piece);
452 remote_peer->current_piece = -1;
455 /** @brief Updates the list of who has a piece from a bitfield
456 * @param peer peer we want to update the list
457 * @param bitfield bitfield
459 void update_pieces_count_from_bitfield(peer_t peer, unsigned int bitfield)
461 for (int i = 0; i < FILE_PIECES; i++) {
462 if (bitfield & (1U << i)) {
463 peer->pieces_count[i]++;
468 /** @brief Return the piece to be downloaded
469 * There are two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
470 * If a piece is partially downloaded, this piece will be selected prioritarily
471 * If the peer has strictly less than 4 pieces, he chooses a piece at random.
472 * If the peer has more than pieces, he downloads the pieces that are the less replicated (rarest policy).
473 * If all pieces have been downloaded or requested, we select a random requested piece (endgame mode).
474 * @param peer: local peer
475 * @param remote_peer: information about the connection
476 * @return the piece to download if possible. -1 otherwise
478 int select_piece_to_download(peer_t peer, connection_t remote_peer)
480 int piece = partially_downloaded_piece(peer, remote_peer);
481 // strict priority policy
486 if (count_pieces(peer->current_pieces) >= (FILE_PIECES - count_pieces(peer->bitfield)) &&
487 (is_interested(peer, remote_peer) != 0)) {
488 #if ENABLE_END_GAME_MODE == 0
491 int nb_interesting_pieces = 0;
492 // compute the number of interesting pieces
493 for (int i = 0; i < FILE_PIECES; i++) {
494 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i)) {
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_has_not_piece(peer, i) && connection_has_piece(remote_peer, i)) {
504 if (random_piece_index == current_index) {
511 xbt_assert(piece != -1);
514 // Random first policy
515 if (count_pieces(peer->bitfield) < 4 && (is_interested_and_free(peer, remote_peer) != 0)) {
516 int nb_interesting_pieces = 0;
517 // compute the number of interesting pieces
518 for (int i = 0; i < FILE_PIECES; i++) {
519 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) &&
520 peer_is_not_downloading_piece(peer, i)) {
521 nb_interesting_pieces++;
524 xbt_assert(nb_interesting_pieces != 0);
525 // get a random interesting piece
526 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
527 int current_index = 0;
528 for (int i = 0; i < FILE_PIECES; i++) {
529 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) &&
530 peer_is_not_downloading_piece(peer, i)) {
531 if (random_piece_index == current_index) {
538 xbt_assert(piece != -1);
540 } else { // Rarest first policy
541 short min = SHRT_MAX;
542 int nb_min_pieces = 0;
543 int current_index = 0;
544 // compute the smallest number of copies of available pieces
545 for (int i = 0; i < FILE_PIECES; i++) {
546 if (peer->pieces_count[i] < min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) &&
547 peer_is_not_downloading_piece(peer, i))
548 min = peer->pieces_count[i];
550 xbt_assert(min != SHRT_MAX || (is_interested_and_free(peer, remote_peer) == 0));
551 // compute the number of rarest pieces
552 for (int i = 0; i < FILE_PIECES; i++) {
553 if (peer->pieces_count[i] == min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) &&
554 peer_is_not_downloading_piece(peer, i))
557 xbt_assert(nb_min_pieces != 0 || (is_interested_and_free(peer, remote_peer) == 0));
558 // get a random rarest piece
559 int random_rarest_index = RngStream_RandInt(peer->stream, 0, nb_min_pieces - 1);
560 for (int i = 0; i < FILE_PIECES; i++) {
561 if (peer->pieces_count[i] == min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) &&
562 peer_is_not_downloading_piece(peer, i)) {
563 if (random_rarest_index == current_index) {
570 xbt_assert(piece != -1 || (is_interested_and_free(peer, remote_peer) == 0));
575 /** @brief Update the list of current choked and unchoked peers, using the choke algorithm
576 * @param peer the current peer
578 void update_choked_peers(peer_t peer)
580 if (nb_interested_peers(peer) == 0)
582 XBT_DEBUG("(%d) update_choked peers %u active peers", peer->id, xbt_dict_size(peer->active_peers));
583 // update the current round
584 peer->round = (peer->round + 1) % 3;
586 char* key_choked = NULL;
587 connection_t peer_choosed = NULL;
588 connection_t peer_choked = NULL;
589 // remove a peer from the list
590 xbt_dict_cursor_t cursor = NULL;
591 xbt_dict_cursor_first(peer->active_peers, &cursor);
592 if (xbt_dict_length(peer->active_peers) > 0) {
593 key_choked = xbt_dict_cursor_get_key(cursor);
594 peer_choked = xbt_dict_cursor_get_data(cursor);
596 xbt_dict_cursor_free(&cursor);
598 /**If we are currently seeding, we unchoke the peer which has been unchoked the last time.*/
599 if (has_finished(peer->bitfield)) {
600 connection_t connection;
601 double unchoke_time = MSG_get_clock() + 1;
603 xbt_dict_foreach (peer->peers, cursor, key, connection) {
604 if (connection->last_unchoke < unchoke_time && (connection->interested != 0) &&
605 (connection->choked_upload != 0)) {
606 unchoke_time = connection->last_unchoke;
607 peer_choosed = connection;
611 // Random optimistic unchoking
612 if (peer->round == 0) {
615 // We choose a random peer to unchoke.
616 int id_chosen = RngStream_RandInt(peer->stream, 0, xbt_dict_length(peer->peers) - 1);
618 connection_t connection;
619 xbt_dict_foreach (peer->peers, cursor, key, connection) {
620 if (i == id_chosen) {
621 peer_choosed = connection;
626 xbt_dict_cursor_free(&cursor);
627 if (peer_choosed == NULL)
628 THROWF(unknown_error, 0, "A peer should have be selected at this point");
629 else if ((peer_choosed->interested == 0) || (peer_choosed->choked_upload == 0))
632 XBT_DEBUG("Nothing to do, keep going");
634 } while (peer_choosed == NULL && j < MAXIMUM_PEERS);
636 // Use the "fastest download" policy.
637 connection_t connection;
638 double fastest_speed = 0.0;
639 xbt_dict_foreach (peer->peers, cursor, key, connection) {
640 if (connection->peer_speed > fastest_speed && (connection->choked_upload != 0) &&
641 (connection->interested != 0)) {
642 peer_choosed = connection;
643 fastest_speed = connection->peer_speed;
649 if (peer_choosed != NULL)
650 XBT_DEBUG("(%d) update_choked peers unchoked (%d) ; int (%d) ; choked (%d) ", peer->id, peer_choosed->id,
651 peer_choosed->interested, peer_choosed->choked_upload);
653 if (peer_choked != peer_choosed) {
654 if (peer_choked != NULL) {
655 xbt_assert((!peer_choked->choked_upload), "Tries to choked a choked peer");
656 peer_choked->choked_upload = 1;
657 xbt_assert((*((int*)key_choked) == peer_choked->id));
658 update_active_peers_set(peer, peer_choked);
659 XBT_DEBUG("(%d) Sending a CHOKE to %d", peer->id, peer_choked->id);
660 send_choked(peer, peer_choked->mailbox);
662 if (peer_choosed != NULL) {
663 xbt_assert((peer_choosed->choked_upload), "Tries to unchoked an unchoked peer");
664 peer_choosed->choked_upload = 0;
665 xbt_dict_set_ext(peer->active_peers, (char*)&peer_choosed->id, sizeof(int), peer_choosed, NULL);
666 peer_choosed->last_unchoke = MSG_get_clock();
667 XBT_DEBUG("(%d) Sending a UNCHOKE to %d", peer->id, peer_choosed->id);
668 update_active_peers_set(peer, peer_choosed);
669 send_unchoked(peer, peer_choosed->mailbox);
674 /** @brief Update "interested" state of peers: send "not interested" to peers that don't have any more pieces we want.
675 * @param peer our peer data
677 void update_interested_after_receive(peer_t peer)
680 xbt_dict_cursor_t cursor;
681 connection_t connection;
682 xbt_dict_foreach (peer->peers, cursor, key, connection) {
683 if (connection->am_interested != 0) {
685 // Check if the peer still has a piece we want.
686 for (int i = 0; i < FILE_PIECES; i++) {
687 if (peer_has_not_piece(peer, i) && connection_has_piece(connection, i)) {
692 if (!interested) { // no more piece to download from connection
693 connection->am_interested = 0;
694 send_notinterested(peer, connection->mailbox);
700 void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length)
702 xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
703 xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.", block_index);
704 for (int i = block_index; i < (block_index + block_length); i++) {
705 peer->bitfield_blocks |= (1ULL << (unsigned int)(index * PIECES_BLOCKS + i));
709 /** Returns if a peer has completed the download of a piece */
710 int piece_complete(peer_t peer, int index)
712 for (int i = 0; i < PIECES_BLOCKS; i++) {
713 if (!(peer->bitfield_blocks & 1ULL << (index * PIECES_BLOCKS + i))) {
720 /** Returns the first block that a peer doesn't have in a piece. If the peer has all blocks of the piece, returns -1. */
721 int get_first_block(peer_t peer, int piece)
723 for (int i = 0; i < PIECES_BLOCKS; i++) {
724 if (!(peer->bitfield_blocks & 1ULL << (piece * PIECES_BLOCKS + i))) {
731 /** Indicates if the remote peer has a piece not stored by the local peer */
732 int is_interested(peer_t peer, connection_t remote_peer)
734 return remote_peer->bitfield & (peer->bitfield ^ ((1 << FILE_PIECES) - 1));
737 /** Indicates if the remote peer has a piece not stored by the local peer nor requested by the local peer */
738 int is_interested_and_free(peer_t peer, connection_t remote_peer)
740 for (int i = 0; i < FILE_PIECES; i++) {
741 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) && peer_is_not_downloading_piece(peer, i)) {
748 /** Returns a piece that is partially downloaded and stored by the remote peer if any -1 otherwise. */
749 int partially_downloaded_piece(peer_t peer, connection_t remote_peer)
751 for (int i = 0; i < FILE_PIECES; i++) {
752 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer, i) && peer_is_not_downloading_piece(peer, i) &&
753 get_first_block(peer, i) > 0)
759 /** @brief Send request messages to a peer that have unchoked us
761 * @param remote_peer peer data to the peer we want to send the request
763 void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece)
765 remote_peer->current_piece = piece;
766 xbt_assert(connection_has_piece(remote_peer, piece));
767 int block_index = get_first_block(peer, piece);
768 if (block_index != -1) {
769 int block_length = MIN(BLOCKS_REQUESTED, PIECES_BLOCKS - block_index);
770 send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
774 /***********************************************************
776 * Low level message functions
778 ***********************************************************/
780 /** @brief Send a "interested" message to a peer
781 * @param peer peer data
782 * @param mailbox destination mailbox
784 void send_interested(peer_t peer, const char* mailbox)
786 msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id,
787 task_message_size(MESSAGE_INTERESTED));
788 MSG_task_dsend(task, mailbox, task_message_free);
789 XBT_DEBUG("Sending INTERESTED to %s", mailbox);
792 /** @brief Send a "not interested" message to a peer
793 * @param peer peer data
794 * @param mailbox destination mailbox
796 void send_notinterested(peer_t peer, const char* mailbox)
798 msg_task_t task = task_message_new(MESSAGE_NOTINTERESTED, peer->hostname, peer->mailbox, peer->id,
799 task_message_size(MESSAGE_NOTINTERESTED));
800 MSG_task_dsend(task, mailbox, task_message_free);
801 XBT_DEBUG("Sending NOTINTERESTED to %s", mailbox);
804 /** @brief Send a handshake message to all the peers the peer has.
805 * @param peer peer data
807 void send_handshake_all(peer_t peer)
809 connection_t remote_peer;
810 xbt_dict_cursor_t cursor = NULL;
812 xbt_dict_foreach (peer->peers, cursor, key, remote_peer) {
813 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
814 task_message_size(MESSAGE_HANDSHAKE));
815 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
816 XBT_DEBUG("Sending a HANDSHAKE to %s", remote_peer->mailbox);
820 /** @brief Send a "handshake" message to an user
821 * @param peer peer data
822 * @param mailbox mailbox where to we send the message
824 void send_handshake(peer_t peer, const char* mailbox)
826 XBT_DEBUG("Sending a HANDSHAKE to %s", mailbox);
827 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
828 task_message_size(MESSAGE_HANDSHAKE));
829 MSG_task_dsend(task, mailbox, task_message_free);
832 /** Send a "choked" message to a peer. */
833 void send_choked(peer_t peer, const char* mailbox)
835 XBT_DEBUG("Sending a CHOKE to %s", mailbox);
837 task_message_new(MESSAGE_CHOKE, peer->hostname, peer->mailbox, peer->id, task_message_size(MESSAGE_CHOKE));
838 MSG_task_dsend(task, mailbox, task_message_free);
841 /** Send a "unchoked" message to a peer */
842 void send_unchoked(peer_t peer, const char* mailbox)
844 XBT_DEBUG("Sending a UNCHOKE to %s", mailbox);
846 task_message_new(MESSAGE_UNCHOKE, peer->hostname, peer->mailbox, peer->id, task_message_size(MESSAGE_UNCHOKE));
847 MSG_task_dsend(task, mailbox, task_message_free);
850 /** Send a "HAVE" message to all peers we are connected to */
851 void send_have(peer_t peer, int piece)
853 XBT_DEBUG("Sending HAVE message to all my peers");
854 connection_t remote_peer;
855 xbt_dict_cursor_t cursor = NULL;
857 xbt_dict_foreach (peer->peers, cursor, key, remote_peer) {
858 msg_task_t task = task_message_index_new(MESSAGE_HAVE, peer->hostname, peer->mailbox, peer->id, piece,
859 task_message_size(MESSAGE_HAVE));
860 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
864 /** @brief Send a bitfield message to all the peers the peer has.
865 * @param peer peer data
867 void send_bitfield(peer_t peer, const char* mailbox)
869 XBT_DEBUG("Sending a BITFIELD to %s", mailbox);
870 msg_task_t task = task_message_bitfield_new(peer->hostname, peer->mailbox, peer->id, peer->bitfield, FILE_PIECES);
871 MSG_task_dsend(task, mailbox, task_message_free);
874 /** Send a "request" message to a pair, containing a request for a piece */
875 void send_request(peer_t peer, const char* mailbox, int piece, int block_index, int block_length)
877 XBT_DEBUG("Sending a REQUEST to %s for piece %d (%d,%d)", mailbox, piece, block_index, block_length);
878 msg_task_t task = task_message_request_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length);
879 MSG_task_dsend(task, mailbox, task_message_free);
882 /** Send a "piece" message to a pair, containing a piece of the file */
883 void send_piece(peer_t peer, const char* mailbox, int piece, int block_index, int block_length)
885 XBT_DEBUG("Sending the PIECE %d (%d,%d) to %s", piece, block_index, block_length, mailbox);
886 xbt_assert(piece >= 0, "Tried to send a piece that doesn't exist.");
887 xbt_assert(!peer_has_not_piece(peer, piece), "Tried to send a piece that we doesn't have.");
889 task_message_piece_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length, BLOCK_SIZE);
890 MSG_task_dsend(task, mailbox, task_message_free);