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 int count_pieces(unsigned int bitfield){
34 count += bitfield & 1;
40 int peer_has_not_piece(peer_t peer, unsigned int piece){
41 return !(peer->bitfield & 1<<piece);
44 /** Check that a piece is not currently being download by the peer. */
45 int peer_is_not_downloading_piece(peer_t peer, unsigned int piece){
46 return !(peer->current_pieces & 1<<piece);
49 void get_status(char **status, unsigned int bitfield){
50 for(int i=FILE_PIECES-1; i>=0; i--)
51 (*status)[i] = (bitfield&(1u<<i))? '1': '0';
52 (*status)[FILE_PIECES] = '\0';
55 /** Peer main function */
56 int peer(int argc, char *argv[])
59 xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
62 peer_t peer = peer_init(xbt_str_parse_int(argv[1],"Invalid ID: %s"), argc==4 ? 1:0);
65 double deadline = xbt_str_parse_double(argv[2],"Invalid deadline: %s");
66 xbt_assert(deadline > 0, "Wrong deadline supplied");
68 char *status = xbt_malloc0(FILE_PIECES+1);
69 get_status(&status, peer->bitfield);
70 XBT_INFO("Hi, I'm joining the network with id %d", peer->id);
71 //Getting peer data from the tracker.
72 if (get_peers_data(peer)) {
73 XBT_DEBUG("Got %d peers from the tracker. Current status is: %s", xbt_dict_length(peer->peers), status);
74 peer->begin_receive_time = MSG_get_clock();
75 MSG_mailbox_set_async(peer->mailbox);
76 if (has_finished(peer->bitfield)) {
77 send_handshake_all(peer);
79 leech_loop(peer, deadline);
81 seed_loop(peer, deadline);
83 XBT_INFO("Couldn't contact the tracker.");
86 get_status(&status, peer->bitfield);
87 XBT_INFO("Here is my current status: %s", status);
88 if (peer->comm_received) {
89 MSG_comm_destroy(peer->comm_received);
97 /** @brief Peer main loop when it is leeching.
98 * @param peer peer data
99 * @param deadline time at which the peer has to leave
101 void leech_loop(peer_t peer, double deadline)
103 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
104 XBT_DEBUG("Start downloading.");
106 /* Send a "handshake" message to all the peers it got (since it couldn't have gotten more than 50 peers) */
107 send_handshake_all(peer);
108 XBT_DEBUG("Starting main leech loop");
110 while (MSG_get_clock() < deadline && count_pieces(peer->bitfield) < FILE_PIECES) {
111 if (peer->comm_received == NULL) {
112 peer->task_received = NULL;
113 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
115 if (MSG_comm_test(peer->comm_received)) {
116 msg_error_t status = MSG_comm_get_status(peer->comm_received);
117 MSG_comm_destroy(peer->comm_received);
118 peer->comm_received = NULL;
119 if (status == MSG_OK) {
120 handle_message(peer, peer->task_received);
123 //We don't execute the choke algorithm if we don't already have a piece
124 if (MSG_get_clock() >= next_choked_update && count_pieces(peer->bitfield) > 0) {
125 update_choked_peers(peer);
126 next_choked_update += UPDATE_CHOKED_INTERVAL;
128 MSG_process_sleep(SLEEP_DURATION);
132 if (has_finished(peer->bitfield))
133 XBT_DEBUG("%d becomes a seeder", peer->id);
136 /** @brief Peer main loop when it is seeding
137 * @param peer peer data
138 * @param deadline time when the peer will leave
140 void seed_loop(peer_t peer, double deadline)
142 double next_choked_update = MSG_get_clock() + UPDATE_CHOKED_INTERVAL;
143 XBT_DEBUG("Start seeding.");
144 //start the main seed loop
145 while (MSG_get_clock() < deadline) {
146 if (peer->comm_received == NULL) {
147 peer->task_received = NULL;
148 peer->comm_received = MSG_task_irecv(&peer->task_received, peer->mailbox);
150 if (MSG_comm_test(peer->comm_received)) {
151 msg_error_t status = MSG_comm_get_status(peer->comm_received);
152 MSG_comm_destroy(peer->comm_received);
153 peer->comm_received = NULL;
154 if (status == MSG_OK) {
155 handle_message(peer, peer->task_received);
158 if (MSG_get_clock() >= next_choked_update) {
159 update_choked_peers(peer);
160 //TODO: Change the choked peer algorithm when seeding.
161 next_choked_update += UPDATE_CHOKED_INTERVAL;
163 MSG_process_sleep(SLEEP_DURATION);
169 /** @brief Retrieves the peer list from the tracker
170 * @param peer current peer data
172 int get_peers_data(peer_t peer)
175 double timeout = MSG_get_clock() + GET_PEERS_TIMEOUT;
177 //Build the task to send to the tracker
178 tracker_task_data_t data = tracker_task_data_new(MSG_host_get_name(MSG_host_self()), peer->mailbox_tracker,
179 peer->id, 0, 0, FILE_SIZE);
180 msg_task_t task_send = MSG_task_create(NULL, 0, TRACKER_COMM_SIZE, data);
181 while ((success == 0) && MSG_get_clock() < timeout) {
182 XBT_DEBUG("Sending a peer request to the tracker.");
183 msg_error_t status = MSG_task_send_with_timeout(task_send, TRACKER_MAILBOX, GET_PEERS_TIMEOUT);
184 if (status == MSG_OK) {
190 msg_task_t task_received = NULL;
191 while ((success == 0) && MSG_get_clock() < timeout) {
192 msg_comm_t comm_received = MSG_task_irecv(&task_received, peer->mailbox_tracker);
193 msg_error_t status = MSG_comm_wait(comm_received, GET_PEERS_TIMEOUT);
194 if (status == MSG_OK) {
195 tracker_task_data_t data = MSG_task_get_data(task_received);
198 //Add the peers the tracker gave us to our peer list.
199 xbt_dynar_foreach(data->peers, i, peer_id) {
200 if (peer_id != peer->id)
201 xbt_dict_set_ext(peer->peers, (char *) &peer_id, sizeof(int), connection_new(peer_id), NULL);
204 //free the communication and the task
205 MSG_comm_destroy(comm_received);
206 tracker_task_data_free(data);
207 MSG_task_destroy(task_received);
214 /** @brief Initialize the peer data.
215 * @param peer peer data
216 * @param id id of the peer to take in the network
217 * @param seed indicates if the peer is a seed.
219 peer_t peer_init(int id, int seed)
221 peer_t peer = xbt_new(s_peer_t,1);
223 peer->hostname = MSG_host_get_name(MSG_host_self());
225 snprintf(peer->mailbox,MAILBOX_SIZE-1, "%d", id);
226 snprintf(peer->mailbox_tracker,MAILBOX_SIZE-1, "tracker_%d", id);
227 peer->peers = xbt_dict_new_homogeneous(NULL);
228 peer->active_peers = xbt_dict_new_homogeneous(NULL);
231 peer->bitfield = (1<<FILE_PIECES)-1;
232 peer->bitfield_blocks = (1L<<(FILE_PIECES * PIECES_BLOCKS))-1;
235 peer->bitfield_blocks = 0;
238 peer->current_pieces = 0;
240 peer->pieces_count = xbt_new0(short, FILE_PIECES);
242 peer->stream = (RngStream)MSG_host_get_data(MSG_host_self());
243 peer->comm_received = NULL;
250 /** Destroys a poor peer object. */
251 void peer_free(peer_t peer)
254 connection_t connection;
255 xbt_dict_cursor_t cursor;
256 xbt_dict_foreach(peer->peers, cursor, key, connection) {
257 connection_free(connection);
259 xbt_dict_free(&peer->peers);
260 xbt_dict_free(&peer->active_peers);
261 xbt_free(peer->pieces_count);
265 /** @brief Returns if a peer has finished downloading the file
266 * @param bitfield peer bitfield
268 int has_finished(unsigned int bitfield)
270 return bitfield == (1<<FILE_PIECES)-1;
273 int nb_interested_peers(peer_t peer)
275 xbt_dict_cursor_t cursor = NULL;
277 connection_t connection;
279 xbt_dict_foreach(peer->peers, cursor, key, connection) {
280 if (connection->interested)
286 void update_active_peers_set(peer_t peer, connection_t remote_peer)
288 if ((remote_peer->interested != 0) && (remote_peer->choked_upload == 0)) {
289 //add in the active peers set
290 xbt_dict_set_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int), remote_peer, NULL);
291 } else if (xbt_dict_get_or_null_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int))) {
292 xbt_dict_remove_ext(peer->active_peers, (char *) &remote_peer->id, sizeof(int));
296 /** @brief Handle a received message sent by another peer
297 * @param peer Peer data
298 * @param task task received.
300 void handle_message(peer_t peer, msg_task_t task)
302 const char* type_names[10] =
303 {"HANDSHAKE","CHOKE","UNCHOKE","INTERESTED","NOTINTERESTED","HAVE","BITFIELD","REQUEST", "PIECE", "CANCEL" };
304 message_t message = MSG_task_get_data(task);
305 XBT_DEBUG("Received a %s message from %s (%s)", type_names[message->type], message->mailbox,
306 message->issuer_host_name);
308 connection_t remote_peer;
309 remote_peer = xbt_dict_get_or_null_ext(peer->peers, (char *) &message->peer_id, sizeof(int));
311 switch (message->type) {
312 case MESSAGE_HANDSHAKE:
313 //Check if the peer is in our connection list.
314 if (remote_peer == 0) {
315 xbt_dict_set_ext(peer->peers, (char *) &message->peer_id, sizeof(int), connection_new(message->peer_id), NULL);
316 send_handshake(peer, message->mailbox);
318 //Send our bitfield to the peer
319 send_bitfield(peer, message->mailbox);
321 case MESSAGE_BITFIELD:
322 //Update the pieces list
323 update_pieces_count_from_bitfield(peer, message->bitfield);
325 remote_peer->bitfield = message->bitfield;
326 xbt_assert(!remote_peer->am_interested, "Should not be interested at first");
327 if (is_interested(peer, remote_peer)) {
328 remote_peer->am_interested = 1;
329 send_interested(peer, message->mailbox);
332 case MESSAGE_INTERESTED:
333 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
334 //Update the interested state of the peer.
335 remote_peer->interested = 1;
336 update_active_peers_set(peer, remote_peer);
338 case MESSAGE_NOTINTERESTED:
339 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
340 remote_peer->interested = 0;
341 update_active_peers_set(peer, remote_peer);
343 case MESSAGE_UNCHOKE:
344 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
345 xbt_assert(remote_peer->choked_download);
346 remote_peer->choked_download = 0;
347 //Send requests to the peer, since it has unchoked us
348 if (remote_peer->am_interested)
349 request_new_piece_to_peer(peer, remote_peer);
352 xbt_assert((remote_peer != NULL), "A non-in-our-list peer has sent us a message. WTH ?");
353 xbt_assert(!remote_peer->choked_download);
354 remote_peer->choked_download = 1;
355 remove_current_piece(peer, remote_peer, remote_peer->current_piece);
358 XBT_DEBUG("\t for piece %d", message->index);
359 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong HAVE message received");
360 remote_peer->bitfield = remote_peer->bitfield | (1<<message->index);
361 peer->pieces_count[message->index]++;
362 //If the piece is in our pieces, we tell the peer that we are interested.
363 if ((remote_peer->am_interested == 0) && peer_has_not_piece(peer,message->index)) {
364 remote_peer->am_interested = 1;
365 send_interested(peer, message->mailbox);
366 if (remote_peer->choked_download == 0)
367 request_new_piece_to_peer(peer, remote_peer);
370 case MESSAGE_REQUEST:
371 xbt_assert(remote_peer->interested);
372 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong request received");
373 if (remote_peer->choked_upload == 0) {
374 XBT_DEBUG("\t for piece %d (%d,%d)", message->index, message->block_index,
375 message->block_index + message->block_length);
376 if (!peer_has_not_piece(peer, message->index)) {
377 send_piece(peer, message->mailbox, message->index, message->block_index, message->block_length);
380 XBT_DEBUG("\t for piece %d but he is choked.", message->peer_id);
384 XBT_DEBUG(" \t for piece %d (%d,%d)", message->index, message->block_index,
385 message->block_index + message->block_length);
386 xbt_assert(!remote_peer->choked_download);
387 xbt_assert(remote_peer->am_interested || ENABLE_END_GAME_MODE,
388 "Can't received a piece if I'm not interested wihtout end-game mode!"
389 "piece (%d) bitfield(%u) remote bitfield(%u)", message->index, peer->bitfield, remote_peer->bitfield);
390 xbt_assert(remote_peer->choked_download != 1, "Can't received a piece if I'm choked !");
391 xbt_assert((message->index >= 0 && message->index < FILE_PIECES), "Wrong piece received");
392 //TODO: Execute à computation.
393 if (peer_has_not_piece(peer,message->index)) {
394 update_bitfield_blocks(peer, message->index, message->block_index, message->block_length);
395 if (piece_complete(peer, message->index)) {
396 //Removing the piece from our piece list
397 remove_current_piece(peer, remote_peer, message->index);
398 //Setting the fact that we have the piece
399 peer->bitfield = peer->bitfield | (1<<message->index);
400 char* status = xbt_malloc0(FILE_PIECES+1);
401 get_status(&status, peer->bitfield);
402 XBT_DEBUG("My status is now %s", status);
404 //Sending the information to all the peers we are connected to
405 send_have(peer, message->index);
406 //sending UNINTERESTED to peers that do not have what we want.
407 update_interested_after_receive(peer);
408 } else { // piece not completed
409 send_request_to_peer(peer, remote_peer, message->index); // ask for the next block
412 XBT_DEBUG("However, we already have it");
413 xbt_assert(ENABLE_END_GAME_MODE, "Should not happen because we don't use end game mode !");
414 request_new_piece_to_peer(peer, remote_peer);
422 //Update the peer speed.
424 connection_add_speed_value(remote_peer, 1.0 / (MSG_get_clock() - peer->begin_receive_time));
426 peer->begin_receive_time = MSG_get_clock();
428 task_message_free(task);
431 /** Selects the appropriate piece to download and requests it to the remote_peer */
432 void request_new_piece_to_peer(peer_t peer, connection_t remote_peer)
434 int piece = select_piece_to_download(peer, remote_peer);
436 peer->current_pieces|= (1 << (unsigned int) piece);
437 send_request_to_peer(peer, remote_peer, piece);
441 /** remove current_piece from the list of currently downloaded pieces. */
442 void remove_current_piece(peer_t peer, connection_t remote_peer, int current_piece)
444 peer->current_pieces &= ~(1 << (unsigned int) current_piece);
445 remote_peer->current_piece = -1;
448 /** @brief Updates the list of who has a piece from a bitfield
449 * @param peer peer we want to update the list
450 * @param bitfield bitfield
452 void update_pieces_count_from_bitfield(peer_t peer, unsigned int bitfield)
454 for (int i = 0; i < FILE_PIECES; i++) {
455 if ((bitfield&(1u<<i))) {
456 peer->pieces_count[i]++;
461 /** @brief Return the piece to be downloaded
462 * There are two cases (as described in "Bittorrent Architecture Protocol", Ryan Toole :
463 * If a piece is partially downloaded, this piece will be selected prioritarily
464 * If the peer has strictly less than 4 pieces, he chooses a piece at random.
465 * If the peer has more than pieces, he downloads the pieces that are the less replicated (rarest policy).
466 * If all pieces have been downloaded or requested, we select a random requested piece (endgame mode).
467 * @param peer: local peer
468 * @param remote_peer: information about the connection
469 * @return the piece to download if possible. -1 otherwise
471 int select_piece_to_download(peer_t peer, connection_t remote_peer)
473 int piece = partially_downloaded_piece(peer, remote_peer);
474 // strict priority policy
479 if (count_pieces(peer->current_pieces) >= (FILE_PIECES - count_pieces(peer->bitfield)) &&
480 (is_interested(peer, remote_peer) != 0)) {
481 #if ENABLE_END_GAME_MODE == 0
484 int nb_interesting_pieces = 0;
485 // compute the number of interesting pieces
486 for (int i = 0; i < FILE_PIECES; i++) {
487 if (peer_has_not_piece(peer,i) && connection_has_piece(remote_peer,i)) {
488 nb_interesting_pieces++;
491 xbt_assert(nb_interesting_pieces != 0);
492 // get a random interesting piece
493 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
494 int current_index = 0;
495 for (int i = 0; i < FILE_PIECES; i++) {
496 if (peer_has_not_piece(peer,i) && connection_has_piece(remote_peer,i)) {
497 if (random_piece_index == current_index) {
504 xbt_assert(piece != -1);
507 // Random first policy
508 if (count_pieces(peer->bitfield) < 4 && (is_interested_and_free(peer, remote_peer) != 0)) {
509 int nb_interesting_pieces = 0;
510 // compute the number of interesting pieces
511 for (int i = 0; i < FILE_PIECES; i++) {
512 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) && peer_is_not_downloading_piece(peer, i)) {
513 nb_interesting_pieces++;
516 xbt_assert(nb_interesting_pieces != 0);
517 // get a random interesting piece
518 int random_piece_index = RngStream_RandInt(peer->stream, 0, nb_interesting_pieces - 1);
519 int current_index = 0;
520 for (int i = 0; i < FILE_PIECES; i++) {
521 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) && peer_is_not_downloading_piece(peer, i)) {
522 if (random_piece_index == current_index) {
529 xbt_assert(piece != -1);
531 } else { // Rarest first policy
532 short min = SHRT_MAX;
533 int nb_min_pieces = 0;
534 int current_index = 0;
535 // compute the smallest number of copies of available pieces
536 for (int i = 0; i < FILE_PIECES; i++) {
537 if (peer->pieces_count[i] < min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) &&
538 peer_is_not_downloading_piece(peer, i))
539 min = peer->pieces_count[i];
541 xbt_assert(min != SHRT_MAX || (is_interested_and_free(peer, remote_peer) ==0));
542 // compute the number of rarest pieces
543 for (int i = 0; i < FILE_PIECES; i++) {
544 if (peer->pieces_count[i] == min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) &&
545 peer_is_not_downloading_piece(peer, i))
548 xbt_assert(nb_min_pieces != 0 || (is_interested_and_free(peer, remote_peer)==0));
549 // get a random rarest piece
550 int random_rarest_index = RngStream_RandInt(peer->stream, 0, nb_min_pieces - 1);
551 for (int i = 0; i < FILE_PIECES; i++) {
552 if (peer->pieces_count[i] == min && peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) &&
553 peer_is_not_downloading_piece(peer, i)) {
554 if (random_rarest_index == current_index) {
561 xbt_assert(piece != -1 || (is_interested_and_free(peer, remote_peer) == 0));
566 /** @brief Update the list of current choked and unchoked peers, using the choke algorithm
567 * @param peer the current peer
569 void update_choked_peers(peer_t peer)
571 if (nb_interested_peers(peer) == 0)
573 XBT_DEBUG("(%d) update_choked peers %d active peers", peer->id, xbt_dict_size(peer->active_peers));
574 //update the current round
575 peer->round = (peer->round + 1) % 3;
577 char *key_choked=NULL;
578 connection_t peer_choosed = NULL;
579 connection_t peer_choked = NULL;
580 //remove a peer from the list
581 xbt_dict_cursor_t cursor = NULL;
582 xbt_dict_cursor_first(peer->active_peers, &cursor);
583 if (xbt_dict_length(peer->active_peers) > 0) {
584 key_choked = xbt_dict_cursor_get_key(cursor);
585 peer_choked = xbt_dict_cursor_get_data(cursor);
587 xbt_dict_cursor_free(&cursor);
589 /**If we are currently seeding, we unchoke the peer which has been unchoked the last time.*/
590 if (has_finished(peer->bitfield)) {
591 connection_t connection;
592 double unchoke_time = MSG_get_clock() + 1;
594 xbt_dict_foreach(peer->peers, cursor, key, connection) {
595 if (connection->last_unchoke < unchoke_time &&
596 (connection->interested != 0) && (connection->choked_upload != 0)) {
597 unchoke_time = connection->last_unchoke;
598 peer_choosed = connection;
602 //Random optimistic unchoking
603 if (peer->round == 0) {
606 //We choose a random peer to unchoke.
607 int id_chosen = RngStream_RandInt(peer->stream, 0, xbt_dict_length(peer->peers) - 1);
609 connection_t connection;
610 xbt_dict_foreach(peer->peers, cursor, key, connection) {
611 if (i == id_chosen) {
612 peer_choosed = connection;
617 xbt_dict_cursor_free(&cursor);
618 if (peer_choosed == NULL)
619 THROWF(unknown_error, 0, "A peer should have be selected at this point");
620 else if ((peer_choosed->interested == 0) || (peer_choosed->choked_upload == 0))
623 XBT_DEBUG("Nothing to do, keep going");
625 } while (peer_choosed == NULL && j < MAXIMUM_PAIRS);
627 //Use the "fastest download" policy.
628 connection_t connection;
629 double fastest_speed = 0.0;
630 xbt_dict_foreach(peer->peers, cursor, key, connection) {
631 if (connection->peer_speed > fastest_speed &&
632 (connection->choked_upload != 0) && (connection->interested != 0)) {
633 peer_choosed = connection;
634 fastest_speed = connection->peer_speed;
640 if (peer_choosed != NULL)
641 XBT_DEBUG("(%d) update_choked peers unchoked (%d) ; int (%d) ; choked (%d) ",
642 peer->id, peer_choosed->id, peer_choosed->interested, peer_choosed->choked_upload);
644 if (peer_choked != peer_choosed) {
645 if (peer_choked != NULL) {
646 xbt_assert((!peer_choked->choked_upload), "Tries to choked a choked peer");
647 peer_choked->choked_upload = 1;
648 xbt_assert((*((int *) key_choked) == peer_choked->id));
649 update_active_peers_set(peer, peer_choked);
650 XBT_DEBUG("(%d) Sending a CHOKE to %d", peer->id, peer_choked->id);
651 send_choked(peer, peer_choked->mailbox);
653 if (peer_choosed != NULL) {
654 xbt_assert((peer_choosed->choked_upload), "Tries to unchoked an unchoked peer");
655 peer_choosed->choked_upload = 0;
656 xbt_dict_set_ext(peer->active_peers, (char *) &peer_choosed->id, sizeof(int), peer_choosed, NULL);
657 peer_choosed->last_unchoke = MSG_get_clock();
658 XBT_DEBUG("(%d) Sending a UNCHOKE to %d", peer->id, peer_choosed->id);
659 update_active_peers_set(peer, peer_choosed);
660 send_unchoked(peer, peer_choosed->mailbox);
665 /** @brief Update "interested" state of peers: send "not interested" to peers that don't have any more pieces we want.
666 * @param peer our peer data
668 void update_interested_after_receive(peer_t peer)
671 xbt_dict_cursor_t cursor;
672 connection_t connection;
674 xbt_dict_foreach(peer->peers, cursor, key, connection) {
676 if (connection->am_interested != 0) {
677 //Check if the peer still has a piece we want.
678 for (int i = 0; i < FILE_PIECES; i++) {
679 if (peer_has_not_piece(peer, i) && connection_has_piece(connection,i)) {
684 if (!interested) { //no more piece to download from connection
685 connection->am_interested = 0;
686 send_notinterested(peer, connection->mailbox);
692 void update_bitfield_blocks(peer_t peer, int index, int block_index, int block_length)
694 xbt_assert((index >= 0 && index <= FILE_PIECES), "Wrong piece.");
695 xbt_assert((block_index >= 0 && block_index <= PIECES_BLOCKS), "Wrong block : %d.", block_index);
696 for (int i = block_index; i < (block_index + block_length); i++) {
697 peer->bitfield_blocks |= (1L<<(index * PIECES_BLOCKS + i));
701 /** Returns if a peer has completed the download of a piece */
702 int piece_complete(peer_t peer, int index)
704 for (int i = 0; i < PIECES_BLOCKS; i++) {
705 if (!(peer->bitfield_blocks & 1L<<(index * PIECES_BLOCKS + i))) {
712 /** Returns the first block that a peer doesn't have in a piece. If the peer has all blocks of the piece, returns -1. */
713 int get_first_block(peer_t peer, int piece)
715 for (int i = 0; i < PIECES_BLOCKS; i++) {
716 if (!(peer->bitfield_blocks & 1L<<(piece * PIECES_BLOCKS + i))) {
723 /** Indicates if the remote peer has a piece not stored by the local peer */
724 int is_interested(peer_t peer, connection_t remote_peer)
726 return !!(remote_peer->bitfield & (peer->bitfield^((1<<FILE_PIECES)-1)));
729 /** Indicates if the remote peer has a piece not stored by the local peer nor requested by the local peer */
730 int is_interested_and_free(peer_t peer, connection_t remote_peer)
732 for (int i = 0; i < FILE_PIECES; i++) {
733 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i) && peer_is_not_downloading_piece(peer, i)) {
740 /** Returns a piece that is partially downloaded and stored by the remote peer if any -1 otherwise. */
741 int partially_downloaded_piece(peer_t peer, connection_t remote_peer)
743 for (int i = 0; i < FILE_PIECES; i++) {
744 if (peer_has_not_piece(peer, i) && connection_has_piece(remote_peer,i)&& peer_is_not_downloading_piece(peer, i)) {
745 if (get_first_block(peer, i) > 0)
752 /** @brief Send request messages to a peer that have unchoked us
754 * @param remote_peer peer data to the peer we want to send the request
756 void send_request_to_peer(peer_t peer, connection_t remote_peer, int piece)
758 remote_peer->current_piece = piece;
759 xbt_assert(connection_has_piece(remote_peer,piece));
760 int block_index = get_first_block(peer, piece);
761 if (block_index != -1) {
762 int block_length = MIN(BLOCKS_REQUESTED, PIECES_BLOCKS - block_index);
763 send_request(peer, remote_peer->mailbox, piece, block_index, block_length);
767 /***********************************************************
769 * Low level message functions
771 ***********************************************************/
773 /** @brief Send a "interested" message to a peer
774 * @param peer peer data
775 * @param mailbox destination mailbox
777 void send_interested(peer_t peer, const char *mailbox)
779 msg_task_t task = task_message_new(MESSAGE_INTERESTED, peer->hostname, peer->mailbox, peer->id,
780 task_message_size(MESSAGE_INTERESTED));
781 MSG_task_dsend(task, mailbox, task_message_free);
782 XBT_DEBUG("Sending INTERESTED to %s", mailbox);
785 /** @brief Send a "not interested" message to a peer
786 * @param peer peer data
787 * @param mailbox destination mailbox
789 void send_notinterested(peer_t peer, const char *mailbox)
791 msg_task_t task = task_message_new(MESSAGE_NOTINTERESTED, peer->hostname, peer->mailbox, peer->id,
792 task_message_size(MESSAGE_NOTINTERESTED));
793 MSG_task_dsend(task, mailbox, task_message_free);
794 XBT_DEBUG("Sending NOTINTERESTED to %s", mailbox);
797 /** @brief Send a handshake message to all the peers the peer has.
798 * @param peer peer data
800 void send_handshake_all(peer_t peer)
802 connection_t remote_peer;
803 xbt_dict_cursor_t cursor = NULL;
805 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
806 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
807 task_message_size(MESSAGE_HANDSHAKE));
808 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
809 XBT_DEBUG("Sending a HANDSHAKE to %s", remote_peer->mailbox);
813 /** @brief Send a "handshake" message to an user
814 * @param peer peer data
815 * @param mailbox mailbox where to we send the message
817 void send_handshake(peer_t peer, const char *mailbox)
819 XBT_DEBUG("Sending a HANDSHAKE to %s", mailbox);
820 msg_task_t task = task_message_new(MESSAGE_HANDSHAKE, peer->hostname, peer->mailbox, peer->id,
821 task_message_size(MESSAGE_HANDSHAKE));
822 MSG_task_dsend(task, mailbox, task_message_free);
825 /** Send a "choked" message to a peer. */
826 void send_choked(peer_t peer, const char *mailbox)
828 XBT_DEBUG("Sending a CHOKE to %s", mailbox);
829 msg_task_t task = task_message_new(MESSAGE_CHOKE, peer->hostname, peer->mailbox, peer->id,
830 task_message_size(MESSAGE_CHOKE));
831 MSG_task_dsend(task, mailbox, task_message_free);
834 /** Send a "unchoked" message to a peer */
835 void send_unchoked(peer_t peer, const char *mailbox)
837 XBT_DEBUG("Sending a UNCHOKE to %s", mailbox);
838 msg_task_t task = task_message_new(MESSAGE_UNCHOKE, peer->hostname, peer->mailbox, peer->id,
839 task_message_size(MESSAGE_UNCHOKE));
840 MSG_task_dsend(task, mailbox, task_message_free);
843 /** Send a "HAVE" message to all peers we are connected to */
844 void send_have(peer_t peer, int piece)
846 XBT_DEBUG("Sending HAVE message to all my peers");
847 connection_t remote_peer;
848 xbt_dict_cursor_t cursor = NULL;
850 xbt_dict_foreach(peer->peers, cursor, key, remote_peer) {
851 msg_task_t task = task_message_index_new(MESSAGE_HAVE, peer->hostname, peer->mailbox, peer->id, piece,
852 task_message_size(MESSAGE_HAVE));
853 MSG_task_dsend(task, remote_peer->mailbox, task_message_free);
857 /** @brief Send a bitfield message to all the peers the peer has.
858 * @param peer peer data
860 void send_bitfield(peer_t peer, const char *mailbox)
862 XBT_DEBUG("Sending a BITFIELD to %s", mailbox);
863 msg_task_t task = task_message_bitfield_new(peer->hostname, peer->mailbox, peer->id, peer->bitfield, FILE_PIECES);
864 MSG_task_dsend(task, mailbox, task_message_free);
867 /** Send a "request" message to a pair, containing a request for a piece */
868 void send_request(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
870 XBT_DEBUG("Sending a REQUEST to %s for piece %d (%d,%d)", mailbox, piece, block_index, block_length);
871 msg_task_t task = task_message_request_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length);
872 MSG_task_dsend(task, mailbox, task_message_free);
875 /** Send a "piece" message to a pair, containing a piece of the file */
876 void send_piece(peer_t peer, const char *mailbox, int piece, int block_index, int block_length)
878 XBT_DEBUG("Sending the PIECE %d (%d,%d) to %s", piece, block_index, block_length, mailbox);
879 xbt_assert(piece >= 0, "Tried to send a piece that doesn't exist.");
880 xbt_assert(!peer_has_not_piece(peer,piece), "Tried to send a piece that we doesn't have.");
881 msg_task_t task = task_message_piece_new(peer->hostname, peer->mailbox, peer->id, piece, block_index, block_length,
883 MSG_task_dsend(task, mailbox, task_message_free);