2 /* Copyright (c) 2010. The SimGrid Team.
3 * All rights reserved. */
5 /* This program is free software; you can redistribute it and/or modify it
6 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #include "xbt/asserts.h"
12 #include "simgrid/modelchecker.h"
15 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
16 "Messages specific for this msg example");
20 #define MAILBOX_NAME_SIZE 10
22 static int nb_bits = 24;
23 static int nb_keys = 0;
24 static int timeout = 1;
25 static int max_simulation_time = 100;
26 static int periodic_stabilize_delay = 5;
27 static int periodic_fix_fingers_delay = 12;
28 static int periodic_check_predecessor_delay = 12;
29 static int periodic_lookup_delay = 5;
34 typedef struct finger {
36 char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id
37 } s_finger_t, *finger_t;
44 char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id)
45 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
46 int pred_id; // predecessor id
47 char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name
48 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
49 msg_comm_t comm_receive; // current communication to receive
50 xbt_dynar_t comms; // current communications being sent
51 double last_change_date; // last time I changed a finger or my predecessor
55 * Types of tasks exchanged between nodes.
59 TASK_FIND_SUCCESSOR_ANSWER,
61 TASK_GET_PREDECESSOR_ANSWER,
63 TASK_SUCCESSOR_LEAVING,
64 TASK_PREDECESSOR_LEAVING
68 * Data attached with the tasks sent and received
70 typedef struct task_data {
71 e_task_type_t type; // type of task
72 int request_id; // id paramater (used by some types of tasks)
73 int request_finger; // finger parameter (used by some types of tasks)
74 int answer_id; // answer (used by some types of tasks)
75 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
76 const char* issuer_host_name; // used for logging
77 } s_task_data_t, *task_data_t;
82 static void chord_initialize(void);
83 static int normalize(int id);
84 static int is_in_interval(int id, int start, int end);
85 static void get_mailbox(int host_id, char* mailbox);
86 static void task_data_destroy(task_data_t task_data);
87 static void print_finger_table(node_t node);
88 static void set_finger(node_t node, int finger_index, int id);
89 static void set_predecessor(node_t node, int predecessor_id);
92 static int node(int argc, char *argv[]);
93 static void handle_task(node_t node, msg_task_t task);
96 static void create(node_t node);
97 static int join(node_t node, int known_id);
98 static void leave(node_t node);
99 static int find_successor(node_t node, int id);
100 static int remote_find_successor(node_t node, int ask_to_id, int id);
101 static int remote_get_predecessor(node_t node, int ask_to_id);
102 static int closest_preceding_node(node_t node, int id);
103 static void stabilize(node_t node);
104 static void notify(node_t node, int predecessor_candidate_id);
105 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
106 static void fix_fingers(node_t node);
107 static void check_predecessor(node_t node);
108 static void random_lookup(node_t);
109 static void quit_notify(node_t node, int to);
112 static int predJoin(void);
116 * \brief Global initialization of the Chord simulation.
118 static void chord_initialize(void)
120 // compute the powers of 2 once for all
121 powers2 = xbt_new(int, nb_bits);
124 for (i = 0; i < nb_bits; i++) {
129 XBT_DEBUG("Sets nb_keys to %d", nb_keys);
133 * \brief Turns an id into an equivalent id in [0, nb_keys).
135 * \return the corresponding normalized id
137 static int normalize(int id)
139 // like id % nb_keys, but works with negatives numbers (and faster)
140 return id & (nb_keys - 1);
144 * \brief Returns whether a id belongs to the interval [start, end].
146 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
147 * 1 belongs to [62, 3]
148 * 1 does not belong to [3, 62]
149 * 63 belongs to [62, 3]
150 * 63 does not belong to [3, 62]
151 * 24 belongs to [21, 29]
152 * 24 does not belong to [29, 21]
154 * \param id id to check
155 * \param start lower bound
156 * \param end upper bound
157 * \return a non-zero value if id in in [start, end]
159 static int is_in_interval(int id, int start, int end)
162 start = normalize(start);
163 end = normalize(end);
165 // make sure end >= start and id >= start
178 * \brief Gets the mailbox name of a host given its chord id.
179 * \param node_id id of a node
180 * \param mailbox pointer to where the mailbox name should be written
181 * (there must be enough space)
183 static void get_mailbox(int node_id, char* mailbox)
185 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
189 * \brief Frees the memory used by some task data.
190 * \param task_data the task data to destroy
192 static void task_data_destroy(task_data_t task_data)
198 * \brief Displays the finger table of a node.
201 static void print_finger_table(node_t node)
203 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
205 XBT_VERB("My finger table:");
206 XBT_VERB("Start | Succ ");
207 for (i = 0; i < nb_bits; i++) {
208 XBT_VERB(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
210 XBT_VERB("Predecessor: %d", node->pred_id);
215 * \brief Sets a finger of the current node.
216 * \param node the current node
217 * \param finger_index index of the finger to set (0 to nb_bits - 1)
218 * \param id the id to set for this finger
220 static void set_finger(node_t node, int finger_index, int id)
222 if (id != node->fingers[finger_index].id) {
223 node->fingers[finger_index].id = id;
224 get_mailbox(id, node->fingers[finger_index].mailbox);
225 node->last_change_date = MSG_get_clock();
226 XBT_DEBUG("My new finger #%d is %d", finger_index, id);
231 * \brief Sets the predecessor of the current node.
232 * \param node the current node
233 * \param id the id to predecessor, or -1 to unset the predecessor
235 static void set_predecessor(node_t node, int predecessor_id)
237 if (predecessor_id != node->pred_id) {
238 node->pred_id = predecessor_id;
240 if (predecessor_id != -1) {
241 get_mailbox(predecessor_id, node->pred_mailbox);
243 node->last_change_date = MSG_get_clock();
245 XBT_DEBUG("My new predecessor is %d", predecessor_id);
250 * \brief Node Function
253 * - the id of a guy I know in the system (except for the first node)
254 * - the time to sleep before I join (except for the first node)
256 int node(int argc, char *argv[])
258 /* Reduce the run size for the MC */
260 periodic_stabilize_delay = 8;
261 periodic_fix_fingers_delay = 8;
262 periodic_check_predecessor_delay = 8;
265 double init_time = MSG_get_clock();
266 msg_task_t task_received = NULL;
267 msg_comm_t comm_send = NULL;
270 int join_success = 0;
272 double next_stabilize_date = init_time + periodic_stabilize_delay;
273 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
274 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
275 double next_lookup_date = init_time + periodic_lookup_delay;
277 xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node");
279 // initialize my node
281 node.id = atoi(argv[1]);
282 get_mailbox(node.id, node.mailbox);
283 node.next_finger_to_fix = 0;
284 node.comms = xbt_dynar_new(sizeof(msg_comm_t), NULL);
285 node.fingers = xbt_new0(s_finger_t, nb_bits);
286 node.last_change_date = init_time;
288 for (i = 0; i < nb_bits; i++) {
289 node.fingers[i].id = -1;
290 set_finger(&node, i, node.id);
293 if (argc == 3) { // first ring
294 deadline = atof(argv[2]);
299 int known_id = atoi(argv[2]);
300 //double sleep_time = atof(argv[3]);
301 deadline = atof(argv[4]);
304 // sleep before starting
305 XBT_DEBUG("Let's sleep during %f", sleep_time);
306 MSG_process_sleep(sleep_time);
308 XBT_INFO("Hey! Let's join the system.");
310 join_success = join(&node, known_id);
319 XBT_INFO("Node %d joined the ring", node.id);
322 while (MSG_get_clock() < init_time + deadline
323 // && MSG_get_clock() < node.last_change_date + 1000
324 && MSG_get_clock() < max_simulation_time) {
326 if (node.comm_receive == NULL) {
327 task_received = NULL;
328 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
329 // FIXME: do not make MSG_task_irecv() calls from several functions
332 if (!MSG_comm_test(node.comm_receive)) {
334 // no task was received: make some periodic calls
335 if (MSG_get_clock() >= next_stabilize_date) {
337 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
339 else if (MSG_get_clock() >= next_fix_fingers_date) {
341 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
343 else if (MSG_get_clock() >= next_check_predecessor_date) {
344 check_predecessor(&node);
345 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
347 else if (MSG_get_clock() >= next_lookup_date) {
348 random_lookup(&node);
349 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
352 // nothing to do: sleep for a while
353 MSG_process_sleep(5);
357 // a transfer has occured
359 msg_error_t status = MSG_comm_get_status(node.comm_receive);
361 if (status != MSG_OK) {
362 XBT_DEBUG("Failed to receive a task. Nevermind.");
363 node.comm_receive = NULL;
366 // the task was successfully received
367 MSG_comm_destroy(node.comm_receive);
368 node.comm_receive = NULL;
369 handle_task(&node, task_received);
374 // see if some communications are finished
375 while ((index = MSG_comm_testany(node.comms)) != -1) {
376 comm_send = xbt_dynar_get_as(node.comms, index, msg_comm_t);
377 msg_error_t status = MSG_comm_get_status(comm_send);
378 xbt_dynar_remove_at(node.comms, index, &comm_send);
379 XBT_DEBUG("Communication %p is finished with status %d, dynar size is now %lu",
380 comm_send, status, xbt_dynar_length(node.comms));
381 msg_task_t task = MSG_comm_get_task(comm_send);
382 MSG_comm_destroy(comm_send);
383 if (status != MSG_OK) {
384 task_data_destroy(MSG_task_get_data(task));
385 MSG_task_destroy(task);
390 // clean unfinished comms sent
391 /* unsigned int cursor;
392 xbt_dynar_foreach(node.comms, cursor, comm_send) {
393 msg_task_t task = MSG_comm_get_task(comm_send);
394 MSG_task_cancel(task);
395 task_data_destroy(MSG_task_get_data(task));
396 MSG_task_destroy(task);
397 MSG_comm_destroy(comm_send);
398 // FIXME: the task is actually not destroyed because MSG thinks that the other side (whose process is dead) is still using it
405 // stop the simulation
406 xbt_dynar_free(&node.comms);
407 xbt_free(node.fingers);
412 * \brief This function is called when the current node receives a task.
413 * \param node the current node
414 * \param task the task to handle (don't touch it then:
415 * it will be destroyed, reused or forwarded)
417 static void handle_task(node_t node, msg_task_t task) {
419 XBT_DEBUG("Handling task %p", task);
420 msg_comm_t comm = NULL;
421 char mailbox[MAILBOX_NAME_SIZE];
422 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
423 e_task_type_t type = task_data->type;
427 case TASK_FIND_SUCCESSOR:
428 XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d",
429 task_data->issuer_host_name, task_data->request_id);
430 // is my successor the successor?
431 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
432 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
433 task_data->answer_id = node->fingers[0].id;
434 XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
435 task_data->issuer_host_name,
436 task_data->answer_to,
437 task_data->request_id, task_data->answer_id);
438 comm = MSG_task_isend(task, task_data->answer_to);
439 xbt_dynar_push(node->comms, &comm);
442 // otherwise, forward the request to the closest preceding finger in my table
443 int closest = closest_preceding_node(node, task_data->request_id);
444 XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
445 task_data->request_id, closest);
446 get_mailbox(closest, mailbox);
447 comm = MSG_task_isend(task, mailbox);
448 xbt_dynar_push(node->comms, &comm);
452 case TASK_GET_PREDECESSOR:
453 XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
454 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
455 task_data->answer_id = node->pred_id;
456 XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
457 task_data->issuer_host_name,
458 task_data->answer_to, task_data->answer_id);
459 comm = MSG_task_isend(task, task_data->answer_to);
460 xbt_dynar_push(node->comms, &comm);
464 // someone is telling me that he may be my new predecessor
465 XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
466 notify(node, task_data->request_id);
467 task_data_destroy(task_data);
468 MSG_task_destroy(task);
471 case TASK_PREDECESSOR_LEAVING:
472 // my predecessor is about to quit
473 XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
474 // modify my predecessor
475 set_predecessor(node, task_data->request_id);
476 task_data_destroy(task_data);
477 MSG_task_destroy(task);
479 >> notify my new predecessor
480 >> send a notify_predecessors !!
484 case TASK_SUCCESSOR_LEAVING:
485 // my successor is about to quit
486 XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
487 // modify my successor FIXME : this should be implicit ?
488 set_finger(node, 0, task_data->request_id);
489 task_data_destroy(task_data);
490 MSG_task_destroy(task);
492 >> notify my new successor
493 >> update my table & predecessors table */
496 case TASK_FIND_SUCCESSOR_ANSWER:
497 case TASK_GET_PREDECESSOR_ANSWER:
498 XBT_DEBUG("Ignoring unexpected task of type %d (%p)", type, task);
499 task_data_destroy(task_data);
500 MSG_task_destroy(task);
506 * \brief Initializes the current node as the first one of the system.
507 * \param node the current node
509 static void create(node_t node)
511 XBT_DEBUG("Create a new Chord ring...");
512 set_predecessor(node, -1); // -1 means that I have no predecessor
513 print_finger_table(node);
517 * \brief Makes the current node join the ring, knowing the id of a node
518 * already in the ring
519 * \param node the current node
520 * \param known_id id of a node already in the ring
521 * \return 1 if the join operation succeeded, 0 otherwise
523 static int join(node_t node, int known_id)
525 XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id);
526 set_predecessor(node, -1); // no predecessor (yet)
528 int successor_id = remote_find_successor(node, known_id, node->id);
529 if (successor_id == -1) {
530 XBT_INFO("Node %d cannot join the ring.", node->id);
533 set_finger(node, 0, successor_id);
534 print_finger_table(node);
537 return successor_id != -1;
541 * \brief Makes the current node quit the system
542 * \param node the current node
544 static void leave(node_t node)
546 XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)");
547 quit_notify(node, 1); // notify to my successor ( >>> 1 );
548 quit_notify(node, -1); // notify my predecessor ( >>> -1);
553 * \brief Notifies the successor or the predecessor of the current node
555 * \param node the current node
556 * \param to 1 to notify the successor, -1 to notify the predecessor
557 * FIXME: notify both nodes with only one call
559 static void quit_notify(node_t node, int to)
562 task_data_t req_data = xbt_new0(s_task_data_t, 1);
563 req_data->request_id = node->id;
564 req_data->successor_id = node->fingers[0].id;
565 req_data->pred_id = node->pred_id;
566 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
567 req_data->answer_to = NULL;
568 const char* task_name = NULL;
569 const char* to_mailbox = NULL;
570 if (to == 1) { // notify my successor
571 to_mailbox = node->fingers[0].mailbox;
572 INFO2("Telling my Successor %d about my departure via mailbox %s",
573 node->fingers[0].id, to_mailbox);
574 req_data->type = TASK_PREDECESSOR_LEAVING;
576 else if (to == -1) { // notify my predecessor
578 if (node->pred_id == -1) {
582 to_mailbox = node->pred_mailbox;
583 INFO2("Telling my Predecessor %d about my departure via mailbox %s",
584 node->pred_id, to_mailbox);
585 req_data->type = TASK_SUCCESSOR_LEAVING;
587 msg_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
588 //char* mailbox = get_mailbox(to_mailbox);
589 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
590 xbt_dynar_push(node->comms, &comm);
595 * \brief Makes the current node find the successor node of an id.
596 * \param node the current node
597 * \param id the id to find
598 * \return the id of the successor node, or -1 if the request failed
600 static int find_successor(node_t node, int id)
602 // is my successor the successor?
603 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
604 return node->fingers[0].id;
607 // otherwise, ask the closest preceding finger in my table
608 int closest = closest_preceding_node(node, id);
609 return remote_find_successor(node, closest, id);
613 * \brief Asks another node the successor node of an id.
614 * \param node the current node
615 * \param ask_to the node to ask to
616 * \param id the id to find
617 * \return the id of the successor node, or -1 if the request failed
619 static int remote_find_successor(node_t node, int ask_to, int id)
623 char mailbox[MAILBOX_NAME_SIZE];
624 get_mailbox(ask_to, mailbox);
625 task_data_t req_data = xbt_new0(s_task_data_t, 1);
626 req_data->type = TASK_FIND_SUCCESSOR;
627 req_data->request_id = id;
628 get_mailbox(node->id, req_data->answer_to);
629 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
631 // send a "Find Successor" request to ask_to_id
632 msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
633 XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
634 msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
637 XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
638 task_sent, ask_to, id);
639 MSG_task_destroy(task_sent);
640 task_data_destroy(req_data);
644 // receive the answer
645 XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
646 task_sent, ask_to, id);
649 if (node->comm_receive == NULL) {
650 msg_task_t task_received = NULL;
651 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
654 res = MSG_comm_wait(node->comm_receive, timeout);
657 XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
660 MSG_comm_destroy(node->comm_receive);
661 node->comm_receive = NULL;
664 msg_task_t task_received = MSG_comm_get_task(node->comm_receive);
665 XBT_DEBUG("Received a task (%p)", task_received);
666 task_data_t ans_data = MSG_task_get_data(task_received);
668 if (MC_is_active()) {
669 MC_assert(task_received == task_sent);
672 if (task_received != task_sent) {
673 // this is not the expected answer
674 MSG_comm_destroy(node->comm_receive);
675 node->comm_receive = NULL;
676 handle_task(node, task_received);
679 // this is our answer
680 XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
681 ans_data->request_id, task_received, id, ans_data->answer_id);
682 successor = ans_data->answer_id;
684 MSG_comm_destroy(node->comm_receive);
685 node->comm_receive = NULL;
686 MSG_task_destroy(task_received);
687 task_data_destroy(req_data);
697 * \brief Asks another node its predecessor.
698 * \param node the current node
699 * \param ask_to the node to ask to
700 * \return the id of its predecessor node, or -1 if the request failed
701 * (or if the node does not know its predecessor)
703 static int remote_get_predecessor(node_t node, int ask_to)
705 int predecessor_id = -1;
707 char mailbox[MAILBOX_NAME_SIZE];
708 get_mailbox(ask_to, mailbox);
709 task_data_t req_data = xbt_new0(s_task_data_t, 1);
710 req_data->type = TASK_GET_PREDECESSOR;
711 get_mailbox(node->id, req_data->answer_to);
712 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
714 // send a "Get Predecessor" request to ask_to_id
715 XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
716 msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
717 msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
720 XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d",
722 MSG_task_destroy(task_sent);
723 task_data_destroy(req_data);
727 // receive the answer
728 XBT_DEBUG("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
729 task_sent, ask_to, req_data->answer_to);
732 if (node->comm_receive == NULL) { // FIXME simplify this
733 msg_task_t task_received = NULL;
734 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
737 res = MSG_comm_wait(node->comm_receive, timeout);
740 XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
743 MSG_comm_destroy(node->comm_receive);
744 node->comm_receive = NULL;
747 msg_task_t task_received = MSG_comm_get_task(node->comm_receive);
748 task_data_t ans_data = MSG_task_get_data(task_received);
750 if (MC_is_active()) {
751 MC_assert(task_received == task_sent);
754 if (task_received != task_sent) {
755 MSG_comm_destroy(node->comm_receive);
756 node->comm_receive = NULL;
757 handle_task(node, task_received);
760 XBT_DEBUG("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
761 task_received, ask_to, ans_data->answer_id);
762 predecessor_id = ans_data->answer_id;
764 MSG_comm_destroy(node->comm_receive);
765 node->comm_receive = NULL;
766 MSG_task_destroy(task_received);
767 task_data_destroy(req_data);
773 return predecessor_id;
777 * \brief Returns the closest preceding finger of an id
778 * with respect to the finger table of the current node.
779 * \param node the current node
780 * \param id the id to find
781 * \return the closest preceding finger of that id
783 int closest_preceding_node(node_t node, int id)
786 for (i = nb_bits - 1; i >= 0; i--) {
787 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
788 return node->fingers[i].id;
795 * \brief This function is called periodically. It checks the immediate
796 * successor of the current node.
797 * \param node the current node
799 static void stabilize(node_t node)
801 XBT_DEBUG("Stabilizing node");
803 // get the predecessor of my immediate successor
805 int successor_id = node->fingers[0].id;
806 if (successor_id != node->id) {
807 candidate_id = remote_get_predecessor(node, successor_id);
810 candidate_id = node->pred_id;
813 // this node is a candidate to become my new successor
814 if (candidate_id != -1
815 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
816 set_finger(node, 0, candidate_id);
818 if (successor_id != node->id) {
819 remote_notify(node, successor_id, node->id);
824 * \brief Notifies the current node that its predecessor may have changed.
825 * \param node the current node
826 * \param candidate_id the possible new predecessor
828 static void notify(node_t node, int predecessor_candidate_id) {
830 if (node->pred_id == -1
831 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
833 set_predecessor(node, predecessor_candidate_id);
834 print_finger_table(node);
837 XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
842 * \brief Notifies a remote node that its predecessor may have changed.
843 * \param node the current node
844 * \param notify_id id of the node to notify
845 * \param candidate_id the possible new predecessor
847 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
849 task_data_t req_data = xbt_new0(s_task_data_t, 1);
850 req_data->type = TASK_NOTIFY;
851 req_data->request_id = predecessor_candidate_id;
852 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
854 // send a "Notify" request to notify_id
855 msg_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
856 XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id);
857 char mailbox[MAILBOX_NAME_SIZE];
858 get_mailbox(notify_id, mailbox);
859 msg_comm_t comm = MSG_task_isend(task, mailbox);
860 xbt_dynar_push(node->comms, &comm);
864 * \brief This function is called periodically.
865 * It refreshes the finger table of the current node.
866 * \param node the current node
868 static void fix_fingers(node_t node) {
870 XBT_DEBUG("Fixing fingers");
871 int i = node->next_finger_to_fix;
872 int id = find_successor(node, node->id + powers2[i]);
875 if (id != node->fingers[i].id) {
876 set_finger(node, i, id);
877 print_finger_table(node);
879 node->next_finger_to_fix = (i + 1) % nb_bits;
884 * \brief This function is called periodically.
885 * It checks whether the predecessor has failed
886 * \param node the current node
888 static void check_predecessor(node_t node)
890 XBT_DEBUG("Checking whether my predecessor is alive");
895 * \brief Performs a find successor request to a random id.
896 * \param node the current node
898 static void random_lookup(node_t node)
900 int id = 1337; // TODO pick a pseudorandom id
901 XBT_DEBUG("Making a lookup request for id %d", id);
902 find_successor(node, id);
905 static int predJoin(void){
910 * \brief Main function.
912 int main(int argc, char *argv[])
915 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
916 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
920 MSG_init(&argc, argv);
922 char **options = &argv[0];
923 while (!strncmp(options[0], "-", 1)) {
925 int length = strlen("-nb_bits=");
926 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
927 nb_bits = atoi(options[0] + length);
928 XBT_DEBUG("Set nb_bits to %d", nb_bits);
932 length = strlen("-timeout=");
933 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
934 timeout = atoi(options[0] + length);
935 XBT_DEBUG("Set timeout to %d", timeout);
938 xbt_assert(0, "Invalid chord option '%s'", options[0]);
944 //const char* platform_file = options[0];
945 //const char* application_file = options[1];
949 MSG_config("model-check/property","promela_chord_liveness");
950 MC_automaton_new_propositional_symbol("join", &predJoin);
952 MSG_create_environment("../msg_platform.xml");
954 MSG_function_register("node", node);
955 MSG_launch_application("deploy_chord_before_dsend_liveness.xml");
957 msg_error_t res = MSG_main();
958 XBT_INFO("Simulation time: %g", MSG_get_clock());