X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/e106f396c86e8656041281680d63735549985879..2bcbbaa9848de60e6d3efc806bd25f20ec2f7790:/examples/msg/mc/chord/chord.c diff --git a/examples/msg/mc/chord/chord.c b/examples/msg/mc/chord/chord.c deleted file mode 100644 index 9d9feae5c1..0000000000 --- a/examples/msg/mc/chord/chord.c +++ /dev/null @@ -1,1013 +0,0 @@ - -/* Copyright (c) 2010. The SimGrid Team. - * All rights reserved. */ - -/* This program is free software; you can redistribute it and/or modify it - * under the terms of the license (GNU LGPL) which comes with this package. */ - -#include -#include "msg/msg.h" -#include "xbt/log.h" -#include "xbt/asserts.h" -#include "simgrid/modelchecker.h" -#include "mc/mc.h" - -/** @addtogroup MSG_examples - * - * - chord/chord.c: Classical Chord P2P protocol - * This example implements the well known Chord P2P protocol. Its - * main advantage is that it constitute a fully working non-trivial - * example. In addition, its implementation is rather efficient, as - * demonstrated in http://hal.inria.fr/inria-00602216/ - */ - - -XBT_LOG_NEW_DEFAULT_CATEGORY(mc_chord, - "Messages specific for this example"); - -#define COMM_SIZE 10 -#define COMP_SIZE 0 -#define MAILBOX_NAME_SIZE 10 - -static int nb_bits = 24; -static int nb_keys = 0; -static int timeout = 50; -//static int max_simulation_time = 1000; -static int periodic_stabilize_delay = 20; -static int periodic_fix_fingers_delay = 120; -static int periodic_check_predecessor_delay = 120; -static int periodic_lookup_delay = 10; - -// Liveness properties verification -static int j = 0; - -static int predJ(){ - return j; -} - -//extern long int smx_total_comms; - -/* - * Finger element. - */ -typedef struct s_finger { - int id; - char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id -} s_finger_t, *finger_t; - -/* - * Node data. - */ -typedef struct s_node { - int id; // my id - char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id) - s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor) - int pred_id; // predecessor id - char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name - int next_finger_to_fix; // index of the next finger to fix in fix_fingers() - msg_comm_t comm_receive; // current communication to receive - double last_change_date; // last time I changed a finger or my predecessor -} s_node_t, *node_t; - -/** - * Types of tasks exchanged between nodes. - */ -typedef enum { - TASK_FIND_SUCCESSOR, - TASK_FIND_SUCCESSOR_ANSWER, - TASK_GET_PREDECESSOR, - TASK_GET_PREDECESSOR_ANSWER, - TASK_NOTIFY, - TASK_SUCCESSOR_LEAVING, - TASK_PREDECESSOR_LEAVING -} e_task_type_t; - -/* - * Data attached with the tasks sent and received - */ -typedef struct s_task_data { - e_task_type_t type; // type of task - int request_id; // id paramater (used by some types of tasks) - int request_finger; // finger parameter (used by some types of tasks) - int answer_id; // answer (used by some types of tasks) - char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any) - const char* issuer_host_name; // used for logging -} s_task_data_t, *task_data_t; - -static int *powers2; - -// utility functions -static void chord_initialize(void); -static void chord_exit(void); -static int normalize(int id); -static int is_in_interval(int id, int start, int end); -static void get_mailbox(int host_id, char* mailbox); -static void task_free(void* task); -static void print_finger_table(node_t node); -static void set_finger(node_t node, int finger_index, int id); -static void set_predecessor(node_t node, int predecessor_id); - -// process functions -static int node(int argc, char *argv[]); -static void handle_task(node_t node, msg_task_t task); - -// Chord core -static void create(node_t node); -static int join(node_t node, int known_id); -static void leave(node_t node); -static int find_successor(node_t node, int id); -static int remote_find_successor(node_t node, int ask_to_id, int id); -static int remote_get_predecessor(node_t node, int ask_to_id); -static int closest_preceding_node(node_t node, int id); -static void stabilize(node_t node); -static void notify(node_t node, int predecessor_candidate_id); -static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id); -static void fix_fingers(node_t node); -static void check_predecessor(node_t node); -static void random_lookup(node_t); -static void quit_notify(node_t node); - - -/** - * \brief Global initialization of the Chord simulation. - */ -static void chord_initialize(void) -{ - // compute the powers of 2 once for all - powers2 = xbt_new(int, nb_bits); - int pow = 1; - int i; - for (i = 0; i < nb_bits; i++) { - powers2[i] = pow; - pow = pow << 1; - } - nb_keys = pow; - XBT_DEBUG("Sets nb_keys to %d", nb_keys); -} - -static void chord_exit(void) -{ - xbt_free(powers2); -} - -/** - * \brief Turns an id into an equivalent id in [0, nb_keys). - * \param id an id - * \return the corresponding normalized id - */ -static int normalize(int id) -{ - // like id % nb_keys, but works with negatives numbers (and faster) - return id & (nb_keys - 1); -} - -/** - * \brief Returns whether an id belongs to the interval [start, end]. - * - * The parameters are noramlized to make sure they are between 0 and nb_keys - 1). - * 1 belongs to [62, 3] - * 1 does not belong to [3, 62] - * 63 belongs to [62, 3] - * 63 does not belong to [3, 62] - * 24 belongs to [21, 29] - * 24 does not belong to [29, 21] - * - * \param id id to check - * \param start lower bound - * \param end upper bound - * \return a non-zero value if id in in [start, end] - */ -static int is_in_interval(int id, int start, int end) -{ - id = normalize(id); - start = normalize(start); - end = normalize(end); - - // make sure end >= start and id >= start - if (end < start) { - end += nb_keys; - } - - if (id < start) { - id += nb_keys; - } - - return id <= end; -} - -/** - * \brief Gets the mailbox name of a host given its chord id. - * \param node_id id of a node - * \param mailbox pointer to where the mailbox name should be written - * (there must be enough space) - */ -static void get_mailbox(int node_id, char* mailbox) -{ - snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id); -} - -/** - * \brief Frees the memory used by a task. - * \param task the MSG task to destroy - */ -static void task_free(void* task) -{ - // TODO add a parameter data_free_function to MSG_task_create? - if(task != NULL){ - xbt_free(MSG_task_get_data(task)); - MSG_task_destroy(task); - task = NULL; - } -} - -/** - * \brief Displays the finger table of a node. - * \param node a node - */ -static void print_finger_table(node_t node) -{ - if (XBT_LOG_ISENABLED(mc_chord, xbt_log_priority_verbose)) { - int i; - XBT_VERB("My finger table:"); - XBT_VERB("Start | Succ "); - for (i = 0; i < nb_bits; i++) { - XBT_VERB(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id); - } - XBT_VERB("Predecessor: %d", node->pred_id); - } -} - -/** - * \brief Sets a finger of the current node. - * \param node the current node - * \param finger_index index of the finger to set (0 to nb_bits - 1) - * \param id the id to set for this finger - */ -static void set_finger(node_t node, int finger_index, int id) -{ - if (id != node->fingers[finger_index].id) { - node->fingers[finger_index].id = id; - get_mailbox(id, node->fingers[finger_index].mailbox); - node->last_change_date = MSG_get_clock(); - XBT_DEBUG("My new finger #%d is %d", finger_index, id); - } -} - -/** - * \brief Sets the predecessor of the current node. - * \param node the current node - * \param id the id to predecessor, or -1 to unset the predecessor - */ -static void set_predecessor(node_t node, int predecessor_id) -{ - if (predecessor_id != node->pred_id) { - node->pred_id = predecessor_id; - - if (predecessor_id != -1) { - get_mailbox(predecessor_id, node->pred_mailbox); - } - node->last_change_date = MSG_get_clock(); - - XBT_DEBUG("My new predecessor is %d", predecessor_id); - } -} - -/** - * \brief Node Function - * Arguments: - * - my id - * - the id of a guy I know in the system (except for the first node) - * - the time to sleep before I join (except for the first node) - */ -int node(int argc, char *argv[]) -{ - /* Reduce the run size for the MC */ - if(MC_is_active()){ - periodic_stabilize_delay = 8; - periodic_fix_fingers_delay = 8; - periodic_check_predecessor_delay = 8; - } - - double init_time = MSG_get_clock(); - msg_task_t task_received = NULL; - int i; - int join_success = 0; - //double deadline; - double next_stabilize_date = init_time + periodic_stabilize_delay; - double next_fix_fingers_date = init_time + periodic_fix_fingers_delay; - double next_check_predecessor_date = init_time + periodic_check_predecessor_delay; - double next_lookup_date = init_time + periodic_lookup_delay; - - //int stab = 0, fix = 0, check = 0, rand_look = 0; - int end = 0; - - xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node"); - - // initialize my node - s_node_t node = {0}; - node.id = atoi(argv[1]); - get_mailbox(node.id, node.mailbox); - node.next_finger_to_fix = 0; - node.fingers = xbt_new0(s_finger_t, nb_bits); - node.last_change_date = init_time; - - for (i = 0; i < nb_bits; i++) { - node.fingers[i].id = -1; - set_finger(&node, i, node.id); - } - - if (argc == 3) { // first ring - //deadline = atof(argv[2]); - create(&node); - join_success = 1; - } - else { - int known_id = atoi(argv[2]); - //double sleep_time = atof(argv[3]); - //deadline = atof(argv[4]); - - /* - // sleep before starting - XBT_DEBUG("Let's sleep during %f", sleep_time); - MSG_process_sleep(sleep_time); - */ - XBT_DEBUG("Hey! Let's join the system."); - - join_success = join(&node, known_id); - - if(join_success) - j = 1; - - //MC_assert(!join_success); - - } - - if (join_success) { - - XBT_INFO("Node %d joined the ring", node.id); - - //while (MSG_get_clock() < init_time + deadline - // && MSG_get_clock() < node.last_change_date + 1000 - //&& MSG_get_clock() < max_simulation_time) { - - //while (!(stab == 1 || fix == 1 || check == 1 || rand_look == 1)) { - - while(1){ - - if (node.comm_receive == NULL) { - task_received = NULL; - node.comm_receive = MSG_task_irecv(&task_received, node.mailbox); - // FIXME: do not make MSG_task_irecv() calls from several functions - } - - if (!MSG_comm_test(node.comm_receive)) { - - #ifdef HAVE_MC - if(MC_is_active()){ - if(end == 0 && MC_random()){ - stabilize(&node); - end = 1; - }else if(end == 0 && MC_random()){ - fix_fingers(&node); - end = 1; - }else if(end == 0 && MC_random()){ - check_predecessor(&node); - end = 1; - }else if(end == 0 && MC_random()){ - random_lookup(&node); - end = 1; - }else{ - MSG_process_sleep(5); - } - }else{ - if (MSG_get_clock() >= next_stabilize_date) { - stabilize(&node); - next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay; - } - else if (MSG_get_clock() >= next_fix_fingers_date) { - fix_fingers(&node); - next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay; - } - else if (MSG_get_clock() >= next_check_predecessor_date) { - check_predecessor(&node); - next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay; - } - else if (MSG_get_clock() >= next_lookup_date) { - random_lookup(&node); - next_lookup_date = MSG_get_clock() + periodic_lookup_delay; - } - else { - // nothing to do: sleep for a while - MSG_process_sleep(5); - } - } - #else - if (MSG_get_clock() >= next_stabilize_date) { - stabilize(&node); - next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay; - } - else if (MSG_get_clock() >= next_fix_fingers_date) { - fix_fingers(&node); - next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay; - } - else if (MSG_get_clock() >= next_check_predecessor_date) { - check_predecessor(&node); - next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay; - } - else if (MSG_get_clock() >= next_lookup_date) { - random_lookup(&node); - next_lookup_date = MSG_get_clock() + periodic_lookup_delay; - } - else { - // nothing to do: sleep for a while - MSG_process_sleep(5); - } - #endif - - }else{ - - if (node.comm_receive) { - - XBT_INFO("A transfer has occured"); - - // a transfer has occured - - msg_error_t status = MSG_comm_get_status(node.comm_receive); - - if (status != MSG_OK) { - XBT_INFO("Failed to receive a task. Nevermind."); - MSG_comm_destroy(node.comm_receive); - node.comm_receive = NULL; - } - else { - // the task was successfully received - XBT_INFO("The task was successfully received by node %d", node.id); - MSG_comm_destroy(node.comm_receive); - node.comm_receive = NULL; - handle_task(&node, task_received); - } - } - } - } - - if (node.comm_receive) { - MSG_comm_destroy(node.comm_receive); - node.comm_receive = NULL; - } - - // leave the ring - leave(&node); - - XBT_INFO("Node %d leave the ring", node.id); - //sleep(15); - } - - // stop the simulation - xbt_free(node.fingers); - return 0; -} - -/** - * \brief This function is called when the current node receives a task. - * \param node the current node - * \param task the task to handle (don't touch it then: - * it will be destroyed, reused or forwarded) - */ -static void handle_task(node_t node, msg_task_t task) { - - XBT_DEBUG("Handling task %p", task); - char mailbox[MAILBOX_NAME_SIZE]; - task_data_t task_data = (task_data_t) MSG_task_get_data(task); - e_task_type_t type = task_data->type; - - switch (type) { - - case TASK_FIND_SUCCESSOR: - XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d", - task_data->issuer_host_name, task_data->request_id); - // is my successor the successor? - if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) { - task_data->type = TASK_FIND_SUCCESSOR_ANSWER; - task_data->answer_id = node->fingers[0].id; - XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d", - task_data->issuer_host_name, - task_data->answer_to, - task_data->request_id, task_data->answer_id); - MSG_task_dsend(task, task_data->answer_to, task_free); - } - else { - // otherwise, forward the request to the closest preceding finger in my table - int closest = closest_preceding_node(node, task_data->request_id); - XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d", - task_data->request_id, closest); - get_mailbox(closest, mailbox); - MSG_task_dsend(task, mailbox, task_free); - } - break; - - case TASK_GET_PREDECESSOR: - XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name); - task_data->type = TASK_GET_PREDECESSOR_ANSWER; - task_data->answer_id = node->pred_id; - XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d", - task_data->issuer_host_name, - task_data->answer_to, task_data->answer_id); - MSG_task_dsend(task, task_data->answer_to, task_free); - break; - - case TASK_NOTIFY: - // someone is telling me that he may be my new predecessor - XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name); - notify(node, task_data->request_id); - task_free(task); - break; - - case TASK_PREDECESSOR_LEAVING: - // my predecessor is about to quit - XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name); - // modify my predecessor - set_predecessor(node, task_data->request_id); - task_free(task); - /*TODO : - >> notify my new predecessor - >> send a notify_predecessors !! - */ - break; - - case TASK_SUCCESSOR_LEAVING: - // my successor is about to quit - XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name); - // modify my successor FIXME : this should be implicit ? - set_finger(node, 0, task_data->request_id); - task_free(task); - /* TODO - >> notify my new successor - >> update my table & predecessors table */ - break; - - case TASK_FIND_SUCCESSOR_ANSWER: - case TASK_GET_PREDECESSOR_ANSWER: - XBT_DEBUG("Ignoring unexpected task of type %d (%p)", (int)type, task); - task_free(task); - break; - } -} - -/** - * \brief Initializes the current node as the first one of the system. - * \param node the current node - */ -static void create(node_t node) -{ - XBT_DEBUG("Create a new Chord ring..."); - set_predecessor(node, -1); // -1 means that I have no predecessor - print_finger_table(node); -} - -/** - * \brief Makes the current node join the ring, knowing the id of a node - * already in the ring - * \param node the current node - * \param known_id id of a node already in the ring - * \return 1 if the join operation succeeded, 0 otherwise - */ -static int join(node_t node, int known_id) -{ - XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id); - set_predecessor(node, -1); // no predecessor (yet) - - /* - int i; - for (i = 0; i < nb_bits; i++) { - set_finger(node, i, known_id); - } - */ - - int successor_id = remote_find_successor(node, known_id, node->id); - if (successor_id == -1) { - XBT_INFO("Cannot join the ring."); - } - else { - set_finger(node, 0, successor_id); - print_finger_table(node); - } - - return successor_id != -1; -} - -/** - * \brief Makes the current node quit the system - * \param node the current node - */ -static void leave(node_t node) -{ - XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)"); - quit_notify(node); -} - -/* - * \brief Notifies the successor and the predecessor of the current node - * of the departure - * \param node the current node - */ -static void quit_notify(node_t node) -{ - char mailbox[MAILBOX_NAME_SIZE]; - //send the PREDECESSOR_LEAVING to our successor - task_data_t req_data = xbt_new0(s_task_data_t,1); - req_data->type = TASK_PREDECESSOR_LEAVING; - req_data->request_id = node->pred_id; - get_mailbox(node->id, req_data->answer_to); - req_data->issuer_host_name = MSG_host_get_name(MSG_host_self()); - - msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data); - XBT_DEBUG("Sending a 'PREDECESSOR_LEAVING' to my successor %d",node->fingers[0].id); - MSG_task_send_with_timeout(task_sent, node->fingers[0].mailbox, timeout); - - //send the SUCCESSOR_LEAVING to our predecessor - get_mailbox(node->pred_id, mailbox); - task_data_t req_data_s = xbt_new0(s_task_data_t,1); - req_data_s->type = TASK_SUCCESSOR_LEAVING; - req_data_s->request_id = node->fingers[0].id; - req_data_s->request_id = node->pred_id; - get_mailbox(node->id, req_data_s->answer_to); - req_data_s->issuer_host_name = MSG_host_get_name(MSG_host_self()); - - msg_task_t task_sent_s = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data_s); - XBT_DEBUG("Sending a 'SUCCESSOR_LEAVING' to my predecessor %d",node->pred_id); - MSG_task_send_with_timeout(task_sent_s, mailbox, timeout); - -} - -/** - * \brief Makes the current node find the successor node of an id. - * \param node the current node - * \param id the id to find - * \return the id of the successor node, or -1 if the request failed - */ -static int find_successor(node_t node, int id) -{ - // is my successor the successor? - if (is_in_interval(id, node->id + 1, node->fingers[0].id)) { - return node->fingers[0].id; - } - - // otherwise, ask the closest preceding finger in my table - int closest = closest_preceding_node(node, id); - return remote_find_successor(node, closest, id); -} - -/** - * \brief Asks another node the successor node of an id. - * \param node the current node - * \param ask_to the node to ask to - * \param id the id to find - * \return the id of the successor node, or -1 if the request failed - */ -static int remote_find_successor(node_t node, int ask_to, int id) -{ - int successor = -1; - int stop = 0; - char mailbox[MAILBOX_NAME_SIZE]; - get_mailbox(ask_to, mailbox); - task_data_t req_data = xbt_new0(s_task_data_t, 1); - req_data->type = TASK_FIND_SUCCESSOR; - req_data->request_id = id; - get_mailbox(node->id, req_data->answer_to); - req_data->issuer_host_name = MSG_host_get_name(MSG_host_self()); - - // send a "Find Successor" request to ask_to_id - msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data); - XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id); - msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout); - - if (res != MSG_OK) { - XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d", - task_sent, ask_to, id); - task_free(task_sent); - } - else { - - // receive the answer - XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer", - task_sent, ask_to, id); - - do { - if (node->comm_receive == NULL) { - msg_task_t task_received = NULL; - node->comm_receive = MSG_task_irecv(&task_received, node->mailbox); - } - - res = MSG_comm_wait(node->comm_receive, timeout); - - if (res != MSG_OK) { - XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d", - task_sent, (int)res); - stop = 1; - MSG_comm_destroy(node->comm_receive); - node->comm_receive = NULL; - } - else { - msg_task_t task_received = MSG_comm_get_task(node->comm_receive); - XBT_DEBUG("Received a task (%p)", task_received); - task_data_t ans_data = MSG_task_get_data(task_received); - - if (MC_is_active()) { - // the model-checker is expected to find a counter-example here. - // - // As you can see in the test right below, task_received is not always equal to task_sent - // (as messages from differing round can interleave). But the previous version of this code - // wrongly assumed that, leading to problems. But this only occured on large platforms, - // leading to hardly usable traces. So we used the model-checker to track down the issue, - // and we came down to this test, that explained the bug in a snap. - //MC_assert(task_received == task_sent); - } - - if (task_received != task_sent) { - // this is not the expected answer - MSG_comm_destroy(node->comm_receive); - node->comm_receive = NULL; - handle_task(node, task_received); - } - else { - // this is our answer - XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d", - ans_data->request_id, task_received, id, ans_data->answer_id); - successor = ans_data->answer_id; - stop = 1; - MSG_comm_destroy(node->comm_receive); - node->comm_receive = NULL; - task_free(task_received); - } - } - } while (!stop); - } - - return successor; -} - -/** - * \brief Asks another node its predecessor. - * \param node the current node - * \param ask_to the node to ask to - * \return the id of its predecessor node, or -1 if the request failed - * (or if the node does not know its predecessor) - */ -static int remote_get_predecessor(node_t node, int ask_to) -{ - int predecessor_id = -1; - int stop = 0; - char mailbox[MAILBOX_NAME_SIZE]; - get_mailbox(ask_to, mailbox); - task_data_t req_data = xbt_new0(s_task_data_t, 1); - req_data->type = TASK_GET_PREDECESSOR; - get_mailbox(node->id, req_data->answer_to); - req_data->issuer_host_name = MSG_host_get_name(MSG_host_self()); - - // send a "Get Predecessor" request to ask_to_id - XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to); - msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data); - msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout); - - if (res != MSG_OK) { - XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d", - task_sent, ask_to); - task_free(task_sent); - } - else { - - // receive the answer - XBT_DEBUG("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'", - task_sent, ask_to, req_data->answer_to); - - do { - if (node->comm_receive == NULL) { // FIXME simplify this - msg_task_t task_received = NULL; - node->comm_receive = MSG_task_irecv(&task_received, node->mailbox); - } - - res = MSG_comm_wait(node->comm_receive, timeout); - - if (res != MSG_OK) { - XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d", - task_sent, (int)res); - stop = 1; - MSG_comm_destroy(node->comm_receive); - node->comm_receive = NULL; - } - else { - msg_task_t task_received = MSG_comm_get_task(node->comm_receive); - task_data_t ans_data = MSG_task_get_data(task_received); - - /*if (MC_is_active()) { - MC_assert(task_received == task_sent); - }*/ - - if (task_received != task_sent) { - MSG_comm_destroy(node->comm_receive); - node->comm_receive = NULL; - handle_task(node, task_received); - } - else { - XBT_DEBUG("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d", - task_received, ask_to, ans_data->answer_id); - predecessor_id = ans_data->answer_id; - stop = 1; - MSG_comm_destroy(node->comm_receive); - node->comm_receive = NULL; - task_free(task_received); - } - } - } while (!stop); - } - - return predecessor_id; -} - -/** - * \brief Returns the closest preceding finger of an id - * with respect to the finger table of the current node. - * \param node the current node - * \param id the id to find - * \return the closest preceding finger of that id - */ -int closest_preceding_node(node_t node, int id) -{ - int i; - for (i = nb_bits - 1; i >= 0; i--) { - if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) { - return node->fingers[i].id; - } - } - return node->id; -} - -/** - * \brief This function is called periodically. It checks the immediate - * successor of the current node. - * \param node the current node - */ -static void stabilize(node_t node) -{ - XBT_DEBUG("Stabilizing node %d", node->id); - - // get the predecessor of my immediate successor - int candidate_id; - int successor_id = node->fingers[0].id; - if (successor_id != node->id) { - candidate_id = remote_get_predecessor(node, successor_id); - } - else { - candidate_id = node->pred_id; - } - - // this node is a candidate to become my new successor - if (candidate_id != -1 - && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) { - set_finger(node, 0, candidate_id); - } - if (successor_id != node->id) { - remote_notify(node, successor_id, node->id); - } -} - -/** - * \brief Notifies the current node that its predecessor may have changed. - * \param node the current node - * \param candidate_id the possible new predecessor - */ -static void notify(node_t node, int predecessor_candidate_id) { - - XBT_DEBUG("Notifying node %d", node->id); - - if (node->pred_id == -1 - || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) { - - set_predecessor(node, predecessor_candidate_id); - print_finger_table(node); - } - else { - XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id); - } -} - -/** - * \brief Notifies a remote node that its predecessor may have changed. - * \param node the current node - * \param notify_id id of the node to notify - * \param candidate_id the possible new predecessor - */ -static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) { - - task_data_t req_data = xbt_new0(s_task_data_t, 1); - req_data->type = TASK_NOTIFY; - req_data->request_id = predecessor_candidate_id; - req_data->issuer_host_name = MSG_host_get_name(MSG_host_self()); - - // send a "Notify" request to notify_id - msg_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data); - XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id); - char mailbox[MAILBOX_NAME_SIZE]; - get_mailbox(notify_id, mailbox); - MSG_task_dsend(task, mailbox, task_free); - } - -/** - * \brief This function is called periodically. - * It refreshes the finger table of the current node. - * \param node the current node - */ -static void fix_fingers(node_t node) { - - XBT_DEBUG("Fixing fingers"); - int i = node->next_finger_to_fix; - int id = find_successor(node, node->id + powers2[i]); - if (id != -1) { - - if (id != node->fingers[i].id) { - set_finger(node, i, id); - print_finger_table(node); - } - node->next_finger_to_fix = (i + 1) % nb_bits; - } -} - -/** - * \brief This function is called periodically. - * It checks whether the predecessor has failed - * \param node the current node - */ -static void check_predecessor(node_t node) -{ - XBT_DEBUG("Checking whether my predecessor is alive"); - // TODO -} - -/** - * \brief Performs a find successor request to a random id. - * \param node the current node - */ -static void random_lookup(node_t node) -{ - int id = 1337; // TODO pick a pseudorandom id - XBT_DEBUG("Making a lookup request for id %d", id); - find_successor(node, id); -} - -/** - * \brief Main function. - */ -int main(int argc, char *argv[]) -{ - MSG_init(&argc, argv); - if (argc < 3) { - printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]); - printf("example: %s ../../msg_platform.xml deploy_chord1.xml\n", argv[0]); - exit(1); - } - - char **options = &argv[1]; - while (!strncmp(options[0], "-", 1)) { - - int length = strlen("-nb_bits="); - if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) { - nb_bits = atoi(options[0] + length); - XBT_DEBUG("Set nb_bits to %d", nb_bits); - } - else { - - length = strlen("-timeout="); - if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) { - timeout = atoi(options[0] + length); - XBT_DEBUG("Set timeout to %d", timeout); - } - else { - xbt_die("Invalid chord option '%s'", options[0]); - } - } - options++; - } - - const char* platform_file = options[0]; - const char* application_file = options[1]; - - chord_initialize(); - - //MSG_config("model-check/property","promela_join"); - MC_automaton_new_propositional_symbol("j", &predJ); - - MSG_create_environment(platform_file); - - MSG_function_register("node", node); - MSG_launch_application(application_file); - - msg_error_t res = MSG_main(); - XBT_INFO("Simulated time: %g", MSG_get_clock()); - - chord_exit(); - - if (res == MSG_OK) - return 0; - else - return 1; -}