+
/* Copyright (c) 2010. The SimGrid Team.
* All rights reserved. */
* under the terms of the license (GNU LGPL) which comes with this package. */
#include <stdio.h>
-#include <math.h>
-#include "msg/msg.h" /* Yeah! If you want to use msg, you need to include msg/msg.h */
-#include "xbt/sysdep.h" /* calloc, printf */
-
-/* Create a log channel to have nice outputs. */
+#include "msg/msg.h"
#include "xbt/log.h"
#include "xbt/asserts.h"
-XBT_LOG_NEW_DEFAULT_CATEGORY(msg_test,
+XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
"Messages specific for this msg example");
-#define KEY_BITS 6
-#define CHORD_NB_KEYS 64
-/*
-* Finger Element
-*/
-typedef struct{
- int id;
- const char *host_name;
- const char *mailbox;
-}finger_elem;
-/*
- * Node Data
+#define NB_BITS 6
+#define NB_KEYS 64
+
+/**
+ * Finger element.
*/
-typedef struct{
- int id; // my id
- const char *host_name; //my host name
- const char* mailbox; //my mailbox
- int fingers_nb; // size of finger list
- finger_elem* fingers; // finger list [ fingers[0] >> Successor
- int next; //next finger to fix
- int pred_id; // predecessor id
- const char* pred_host_name; // predecessor host name
- const char* pred_mailbox; // predecessor mailbox
-}data_node;
-
-//global;
-
-int get_node_from_key(int key);
-int node(int argc, char *argv[]);
-int sender(int argc,char *argv[]);
-void find_successor_node(data_node *my_data, m_task_t join_task);
-finger_elem find_finger_elem(data_node* my_data, int id);
-const char* find_closest_preceding(data_node* n_node, int id); //return a mailbox
-int get_successor_id(m_host_t);
-//need by qsort function
-int compare (const void * a, const void * b)
-{
- return ( *(int*)a - *(int*)b );
+typedef struct finger {
+ int id;
+ char* mailbox;
+} s_finger_t, *finger_t;
+
+/**
+ * Node data.
+ */
+typedef struct node {
+ int id; // my id
+ char* mailbox;
+ s_finger_t fingers[NB_BITS]; // finger table (fingers[0] is my successor)
+ int pred_id; // predecessor id
+ char* pred_mailbox;
+ xbt_dynar_t comms; // current communications to finish
+} s_node_t, *node_t;
+
+/**
+ * Task data
+ */
+typedef struct task_data {
+ int request_id;
+ int request_finger;
+ int answer_id;
+ const char* answer_to;
+ const char* issuer_host_name; // used for logging
+ int successor_id; // used when quitting
+ int pred_id; // used when quitting
+} s_task_data_t, *task_data_t;
+
+// utility functions
+static int normalize(int id);
+static int is_in_interval(int id, int start, int end);
+static char* get_mailbox(int host_id);
+static void print_finger_table(node_t node);
+
+// process functions
+static int node(int argc, char *argv[]);
+
+// initialization
+static void initialize_first_node(node_t node);
+static void initialize_finger_table(node_t data, int known_id);
+static void join(node_t node, int known_id);
+static void leave(node_t node);
+
+// Chord core
+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 find_predecessor(node_t node, int id);
+static int remote_find_predecessor(node_t node, int ask_to_id, int id);
+static int closest_preceding_finger(node_t node, int id);
+static int remote_closest_preceding_finger(int ask_to_id, int id);
+static void notify_predecessors(node_t node);
+static void remote_move_keys(node_t node, int take_from_id);
+static void update_finger_table(node_t node, int candidate_id, int finger_index);
+static void remote_update_finger_table(node_t node, int ask_to_id, int candidate_id, int finger_index);
+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 stabilize(node_t node);
+static void quit_notify(node_t node, int to);
+
+/**
+ * \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) {
+
+ // make sure id >= 0
+ while (id < 0) {
+ id += NB_KEYS;
+ }
+ // make sure id < NB_KEYS
+ id = id % NB_KEYS;
+
+ return id;
}
-MSG_error_t test_all(const char *platform_file,
- const char *application_file);
+/**
+ * \brief Returns whether a id belongs to the interval [start, end].
+ *
+ * The parameters are noramlized to make sure they are between 0 and CHORD_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);
-static int is_in_interval(unsigned int id, unsigned int start, unsigned int end) {
+ // make sure end >= start and id >= start
+ if (end < start) {
+ end += NB_KEYS;
+ }
-id = id % CHORD_NB_KEYS;
-start = start % CHORD_NB_KEYS;
-end = end % CHORD_NB_KEYS;
+ if (id < start) {
+ id += NB_KEYS;
+ }
-/* make sure end >= start and id >= start */
-if (end < start) {
-end += CHORD_NB_KEYS;
+ return id <= end;
}
-if (id < start) {
-id += CHORD_NB_KEYS;
-}
+/**
+ * \brief Gets the mailbox name of a host given its chord id.
+ * \param node_id id of a node
+ * \return the name of its mailbox
+ * FIXME: free the memory
+ */
+static char* get_mailbox(int node_id) {
-return id < end;
+ return bprintf("mailbox%d", node_id);
}
-
-/*
- * Node Function
+/**
+ * \brief Displays the finger table of a node.
+ * \param node a node
*/
+static void print_finger_table(node_t node) {
+
+ int i;
+ int pow = 1;
+ INFO0("My finger table:");
+ INFO0("Start | Succ ");
+ for (i = 0; i < NB_BITS; i++) {
+ INFO2(" %3d | %3d ", (node->id + pow) % NB_KEYS, node->fingers[i].id);
+ pow = pow << 1;
+ }
+ INFO1("Predecessor: %d", node->pred_id);
+}
-/*<process host="host_name" function="node">
- <argument value="id"/> <!-- my id -->
- <argument value="mailbox"/> <!-- mailbox -->
- <!-- optional -->
- <argument value="known_host_name" />
- <argument value="knwon_host_mailbox" />
- >argument value="time_to_sleep"/>
- </process>
-*/
-static int cpt = 0;
+/**
+ * \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[])
{
- m_task_t recv_request = NULL;
- int first = 1;
- int joined = 0;
- int res,create = 0;
- if ( argc == 3) // if no known host are declared >>> first node >>> create chord ring
- {
- create = 1;
- }
+ double init_time = MSG_get_clock();
+ msg_comm_t comm = NULL;
+ int i;
+ char* mailbox;
+ double deadline;
- int id = atoi(argv[1]);
- int mailbox = atoi(argv[2]);
- // init data node
- data_node *data = xbt_new(data_node,1);
- data->host_name = MSG_host_get_name(MSG_host_self());
- data->id = atoi(argv[1]);
- data->mailbox = argv[2];
- data->fingers_nb = 1;
- data->fingers = xbt_new(finger_elem,KEY_BITS);
- data->fingers[0].host_name = data->host_name;
- data->fingers[0].id = data->id;
- data->fingers[0].mailbox = data->mailbox;
- data->next = 0;
- data->pred_host_name = NULL;
- data->pred_id = -1;
- data->pred_mailbox = NULL;
+ xbt_assert0(argc == 3 || argc == 5, "Wrong number of arguments for this node");
+
+ // initialize my node
+ s_node_t node = {0};
+ node.id = atoi(argv[1]);
+ node.mailbox = get_mailbox(node.id);
+ node.comms = xbt_dynar_new(sizeof(msg_comm_t), NULL);
+
+
+ if (argc == 3) { // first ring
+ initialize_first_node(&node);
+ deadline = atof(argv[2]);
+ }
+ else {
+ int known_id = atoi(argv[2]);
+ double sleep_time = atof(argv[3]);
+ deadline = atof(argv[4]);
+ // sleep before starting
+ INFO1("Let's sleep >>%f", sleep_time);
+ MSG_process_sleep(sleep_time);
+ INFO0("Hey! Let's join the system.");
+
+ join(&node, known_id);
+ }
+
+ while ((MSG_get_clock( )- init_time) < deadline) {
+
+ unsigned int cursor;
+ comm = NULL;
+ xbt_dynar_foreach(node.comms, cursor, comm) {
+ if (MSG_comm_test(comm)) { // FIXME: try with MSG_comm_testany instead
+ xbt_dynar_cursor_rm(node.comms, &cursor);
+ MSG_comm_destroy(comm);
+ }
+ }
+
+ m_task_t task = NULL;
+ MSG_error_t res = MSG_task_receive_with_timeout(&task, node.mailbox,45); // FIXME >> find the right timeout !!
+
+ if(res == MSG_OK) // else check deadline condition and keep waiting for a task
+ {
+
+ // get data
+ const char* task_name = MSG_task_get_name(task);
+ task_data_t task_data = (task_data_t) MSG_task_get_data(task);
+
+ if (!strcmp(task_name, "Find Successor")) {
+ INFO2("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->answer_id = node.fingers[0].id;
+ MSG_task_set_name(task, "Find Successor Answer");
+ INFO3("Sending back a 'Find Successor' Answer to %s: the successor of %d is %d", task_data->issuer_host_name, task_data->request_id, task_data->answer_id);
+ comm = MSG_task_isend(task, task_data->answer_to);
+ xbt_dynar_push(node.comms, &comm);
+ }
+ else {
+ // otherwise, forward the request to the closest preceding finger in my table
+ int closest = closest_preceding_finger(&node, task_data->request_id);
+ INFO2("Forwarding 'Find Successor' request for id %d to my closest preceding finger %d", task_data->request_id, closest);
+ mailbox = get_mailbox(closest);
+ comm = MSG_task_isend(task, mailbox);
+ xbt_dynar_push(node.comms, &comm);
+ xbt_free(mailbox);
+ }
+ }
+
+ else if (!strcmp(task_name, "Find Predecessor")) {
+ INFO2("Receiving a 'Find Predecessor' Request from %s for id %d", task_data->issuer_host_name, task_data->request_id);
+ // am I the predecessor?
+ if (is_in_interval(task_data->request_id, node.id + 1, node.fingers[0].id)) {
+ task_data->answer_id = node.id;
+ MSG_task_set_name(task, "Find Predecessor Answer");
+ INFO3("Sending back a 'Find Predecessor' Answer to %s: the predecessor of %d is %d", task_data->issuer_host_name, task_data->request_id, task_data->answer_id);
+ comm = MSG_task_isend(task, task_data->answer_to);
+ xbt_dynar_push(node.comms, &comm);
+ }
+ else {
+ // otherwise, forward the request to the closest preceding finger in my table
+ int closest = closest_preceding_finger(&node, task_data->request_id);
+ INFO2("Forwarding 'Find Predecessor' request for id %d to my closest preceding finger %d", task_data->request_id, closest);
+ mailbox = get_mailbox(closest);
+ comm = MSG_task_isend(task, mailbox);
+ xbt_dynar_push(node.comms, &comm);
+ xbt_free(mailbox);
+ }
+ }
+
+ else if (!strcmp(task_name, "Update Finger")) {
+ // someone is telling me that he may be my new finger
+ INFO1("Receiving an 'Update Finger' request from %s", task_data->issuer_host_name);
+ update_finger_table(&node, task_data->request_id, task_data->request_finger);
+ }
+ else if (!strcmp(task_name, "Notify")) {
+ // someone is telling me that he may be my new predecessor
+ INFO1("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
+ notify(&node, task_data->request_id);
+ }
+ else if (!strcmp(task_name, "Predecessor Leaving")) {
+ // my predecessor is about quitting
+ INFO1("Receiving a 'quite notify' from %s", task_data->issuer_host_name);
+ // modify my predecessor
+ node.pred_id = task_data->pred_id;
+ node.pred_mailbox = get_mailbox(node.id);
+ /*TODO :
+ >> notify my new predecessor
+ >> send a notify_predecessors !!
+ */
+
+ }
+ else if (!strcmp(task_name, "Successor Leaving")) {
+ // my successor is about quitting
+ INFO1("Receiving a 'quite notify' from %s", task_data->issuer_host_name);
+ // modify my successor FIXME : this should be implicit ?
+ node.fingers[0].id = task_data->successor_id;
+ node.fingers[0].mailbox = get_mailbox(node.fingers[0].id);
+ /* TODO
+ >> notify my new successor
+ >> update my table & predecessors table */
+ }
+ }
+ }
+ // leave the ring and quit simulation
+ leave(&node);
+ xbt_dynar_free(&node.comms);
+ xbt_free(node.mailbox);
+ xbt_free(node.pred_mailbox);
+ for (i = 0; i < NB_BITS - 1; i++) {
+ xbt_free(node.fingers[i].mailbox);
+ }
+ return 1;
+}
+
+/**
+ * \brief Initializes the current node as the first one of the system.
+ * \param node the current node
+ */
+static void initialize_first_node(node_t node)
+{
+ INFO0("Create a new Chord ring...");
+
+ // I am my own successor and predecessor
+ int i;
+ for (i = 0; i < NB_BITS; i++) {
+ node->fingers[i].id = node->id;
+ node->fingers[i].mailbox = xbt_strdup(node->mailbox);
+ }
+ node->pred_id = node->id;
+ node->pred_mailbox = node->mailbox;
+ print_finger_table(node);
+}
+
+/**
+ * \brief Makes the current node join the system, knowing the id of a node already in the system
+ * \param node the current node
+ * \param known_id id of a node already in the system
+ */
+static void join(node_t node, int known_id)
+{
+ initialize_finger_table(node, known_id); // determine my fingers, asking to known_id
+ remote_notify(node, node->fingers[0].id, node->id); // tell my successor that I'm his new predecessor
+ notify_predecessors(node); // tell others that I may have became their finger
+ remote_move_keys(node, node->fingers[0].id); // take some key-value pairs from my successor
+}
+
+/**
+ * \brief Makes the current node quit the system
+ * \param node the current node
+ */
+static void leave(node_t node)
+{
+ INFO0("Well Guys! I Think it's time for me to quit ;)");
+ quit_notify(node,1); // notify to my successor ( >>> 1 );
+ quit_notify(node,-1); // notify my predecessor ( >>> -1);
+ // TODO ...
+}
/*
- * Ring Point Entry Node
+ * \brief Notify msg to tell my successor||predecessor about my departure
+ * \param node the current node
*/
- if (create) // first ring
+static void quit_notify(node_t node, int to)
+{
+ task_data_t req_data = xbt_new0(s_task_data_t, 1);
+ req_data->request_id = node->id;
+ req_data->successor_id = node->fingers[0].id;
+ req_data->pred_id = node->pred_id;
+ req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
+ const char *task_name = NULL;
+ const char* to_mailbox = NULL;
+ if( to == 1) // notify my successor
{
- INFO0("Create new Chord Ring...");
- joined = 1;
- cpt++;
- //sucessor = n
- data->fingers[0].host_name = data->host_name;
- data->fingers[0].id = data->id;
- data->fingers[0].mailbox = data->mailbox;
- while(cpt < MSG_get_host_number()-1) //make condition!!!
- {
- recv_request = NULL;
- res = MSG_task_receive(&(recv_request),data->mailbox);
- xbt_assert0(res == MSG_OK, "MSG_receiev failed");
- if (!strcmp(MSG_task_get_name(recv_request), "Join Call"))
- {
- if(MSG_task_get_data(recv_request)==NULL)
- {
- WARN0("Receiving an Empty Data");
- }
- data_node *recv_data = (data_node*)MSG_task_get_data(recv_request);
- INFO1("Receiving a Join Call from %s",recv_data->host_name);
- if (first)
- {
- // predecessor(recv_data) >>>> data
- recv_data->pred_host_name = data->host_name;
- recv_data->pred_id = data->id;
- recv_data->pred_mailbox = data->mailbox;
- data->fingers_nb = 1;
- // successor(recv_data) >>> data
- recv_data->fingers[0].id = data->id;
- recv_data->fingers[0].host_name = data->host_name;
- recv_data->fingers[0].mailbox = data->mailbox;
- //successor(data) >>>> recv_data
- data->fingers[data->fingers_nb - 1].host_name = recv_data->host_name;
- data->fingers[data->fingers_nb - 1].id = recv_data->id;
- data->fingers[data->fingers_nb - 1].mailbox = recv_data->mailbox;
- INFO1("Sending back a Join Request to %s",recv_data->host_name);
- MSG_task_set_name(recv_request,"Join Response");
- MSG_task_send(recv_request,recv_data->mailbox);
- first = 0;
- }
- else{
- find_successor_node(data,recv_request);
- }
-
- }
- }
+ to_mailbox = node->fingers[0].mailbox;
+ INFO1("Telling my Successor about my departure via mailbox %s", to_mailbox);
+ task_name = "Predecessor Leaving";
+
}
-/*
- * Joining Node
- */
- else if(!create)
+ else if(to == -1) // notify my predecessor
{
- //Sleep Before Starting
- INFO1("Let's Sleep >>%i",atoi(argv[6]));
- MSG_process_sleep(atoi(argv[5]));
- INFO0("Hey! Let's Send a Join Request");
- //send a join task to the known host via its(known host) mailbox
- const char* known_host_name = argv[3];
- const char* known_mailbox = argv[4];
- int known_id = atoi(argv[5]);
- m_task_t join_request = MSG_task_create("Join Call",10000,2000,data); // define comp size and comm size (#define ...)
- INFO2("Sending a join request to %s via mailbox %s",known_host_name,known_mailbox);
- MSG_task_send(join_request,known_mailbox);
- //wait for answer on my mailbox
- while(cpt < MSG_get_host_number()-1)
- {
- recv_request = NULL;
- int res = MSG_task_receive(&(recv_request),data->mailbox);
- //check if it's the response for my request
- xbt_assert0(res == MSG_OK, "MSG_receiev failed");
- // get data
- data_node *recv_data = (data_node*)MSG_task_get_data(recv_request);
- // Join Call Message
- if(!strcmp(MSG_task_get_name(recv_request), "Join Call"))
- {
-
- INFO1("Receiving Join Call From %s",recv_data->host_name);
- if(!joined)
- {
- INFO1("Sorry %s... I'm not yet joined",recv_data->host_name);
- //No Treatment
- MSG_task_set_name(recv_request,"Join Failed");
- MSG_task_send(recv_request,recv_data->mailbox);
- }
- else
- {
- find_successor_node(data,recv_request);
- }
-
- }
- // Join Response
- else if(!strcmp(MSG_task_get_name(recv_request), "Join Response"))
- {
- INFO0("Receiving Join Response!!!");
- INFO1("My successor is : %s",data->fingers[0].host_name);
- INFO1("My Predecessor is : %s",data->pred_host_name);
- cpt++;
- joined = 1;
- INFO1("My finger table size : %i",data->fingers_nb);
- INFO0("***********************************************************************");
-
- /*
- MSG_task_set_name(recv_request,"Fix Fingers");
-
- MSG_task_send(recv_request,data->pred_mailbox);
- MSG_task_send(recv_request,data->fingers[0].mailbox);
- */
- //init_finger_table(data,known_id);
-
- //treatment
- }
- // Join Failure Message
- else if(!strcmp(MSG_task_get_name(recv_request), "Join Failed"))
- {
- INFO0("My Join call has failed... let's Try Again");
- // send back
- //MSG_task_send(join_request,known_mailbox);
- // !!!!!!!!! YVes Jaques Always...???ยงยงยงยง**************************
-
- }
- else if(!strcmp(MSG_task_get_name(recv_request), "Fix Fingers"))
- {
- int i;
- for(i = KEY_BITS -1 ; i>= 0;i--)
- {
- data->fingers[i] = find_finger_elem(data,(data->id)+pow(2,i-1));
- }
- }
- }
+ to_mailbox = node->pred_mailbox;
+ INFO1("Telling my Predecessor about my departure via mailbox %s",to_mailbox);
+ task_name = "Predecessor Leaving";
}
+ m_task_t task = MSG_task_create(task_name, 1000, 5000, req_data);
+ //char* mailbox = get_mailbox(to_mailbox);
+ msg_comm_t comm = MSG_task_isend(task, to_mailbox);
+ xbt_dynar_push(node->comms, &comm);
}
/*
- *
+ * \brief Initializes my finger table, knowing the id of a node already in the system.
+ * \param node the current node
+ * \param known_id id of a node already in the system
*/
-void find_successor_node(data_node* n_data,m_task_t join_task) //use all data
+static void initialize_finger_table(node_t node, int known_id)
{
- //get recv data
- data_node *recv_data = (data_node*)MSG_task_get_data(join_task);
- INFO3("recv_data->id : %i , n_data->id :%i , successor->id :%i",recv_data->id,n_data->id,n_data->fingers[0].id);
- //if ((recv_data->id >= n_data->id) && (recv_data->id <= n_data->fingers[0].id))
- if (is_in_interval(recv_data->id,n_data->id,n_data->fingers[0].id))
- {
- INFO1("Successor Is %s",n_data->fingers[0].host_name);
- //predecessor(recv_data) >>>> n_data
- recv_data->pred_host_name = n_data->host_name;
- recv_data->pred_id = n_data->id;
- recv_data->pred_mailbox = n_data->pred_mailbox;
- // successor(recv_data) >>>> n_data.finger[0]
- recv_data->fingers_nb = 1;
- recv_data->fingers[0].host_name = n_data->fingers[0].host_name;
- recv_data->fingers[0].id = n_data->fingers[0].id;
- recv_data->fingers[0].mailbox = n_data->fingers[0].mailbox;
- // successor(n_data) >>>> recv_sucessor
- n_data->fingers[0].id = recv_data->id;
- n_data->fingers[0].host_name = recv_data->host_name;
- n_data->fingers[0].mailbox = recv_data->mailbox;
- // Logs
- INFO1("Sending back a Join Request to %s",recv_data->host_name);
- MSG_task_set_name(join_task,"Join Response");
- MSG_task_send(join_task,recv_data->mailbox);
- }
+ int my_id = node->id;
+ int i;
+ int pow = 1; // 2^i
+
+ INFO0("Initializing my finger table...");
+
+ // ask known_id who is my immediate successor
+ node->fingers[0].id = remote_find_successor(node, known_id, my_id + 1);
+ node->fingers[0].mailbox = get_mailbox(node->fingers[0].id);
+
+ // find all other fingers
+ for (i = 0; i < NB_BITS - 1; i++) {
+
+ pow = pow << 1; // equivalent to pow = pow * 2
+ if (is_in_interval(my_id + pow, my_id, node->fingers[i].id - 1)) {
+ // I already have the info for this finger
+ node->fingers[i + 1].id = node->fingers[i].id;
+ }
+ else {
+ // I don't have the info, ask the only guy I know
+ node->fingers[i + 1].id = remote_find_successor(node, known_id, my_id + pow);
+ }
+ node->fingers[i + 1].mailbox = get_mailbox(node->fingers[i + 1].id);
+ }
- else
- {
- const char* closest_preceding_mailbox = find_closest_preceding(n_data,recv_data->id);
- INFO1("Forwarding Join Call to mailbox %s",closest_preceding_mailbox);
- MSG_task_send(join_task,closest_preceding_mailbox);
- }
+ node->pred_id = find_predecessor(node, node->id);
+ node->pred_mailbox = get_mailbox(node->pred_id);
+
+ INFO0("Finger table initialized!");
+ print_finger_table(node);
}
-const char* find_closest_preceding(data_node* n_node,int id)
+/**
+ * \brief Notifies some nodes that the current node may have became their finger.
+ * \param node the current node, which has just joined the system
+ */
+static void notify_predecessors(node_t node)
{
- int i;
- for(i = n_node->fingers_nb-1; i >= 0 ; i--)
- {
- if (n_node->fingers[i].id <= id)
- return n_node->fingers[i].mailbox;
- }
+ int i, pred_id;
+ int pow = 1;
+ for (i = 0; i < NB_BITS; i++) {
+ // find the closest node whose finger #i can be me
+ pred_id = find_predecessor(node, node->id - pow + 1); // note: no "+1" in the article!
+ if (pred_id != node->id) {
+ remote_update_finger_table(node, pred_id, node->id, i);
+ }
+ pow = pow << 1; // pow = pow * 2
+ }
+}
+
+/**
+ * \brief Tells the current node that a node may have became its new finger.
+ * \param node the current node
+ * \param candidate_id id of the node that may be a new finger of the current node
+ * \param finger_index index of the finger to update
+ */
+static void update_finger_table(node_t node, int candidate_id, int finger_index)
+{
+ int pow = 1;
+ int i;
+ for (i = 0; i < finger_index; i++) {
+ pow = pow << 1;
+ }
- return n_node->mailbox; // !!!!!!!!!!!!!!
+ // if (is_in_interval(candidate_id, node->id + pow, node->fingers[finger_index].id - 1)) {
+ if (is_in_interval(candidate_id, node->id, node->fingers[finger_index].id - 1)) {
+// INFO3("Candidate %d is between %d and %d!", candidate_id, node->id + pow, node->fingers[finger_index].id - 1);
+ // candidate_id is my new finger
+ xbt_free(node->fingers[finger_index].mailbox);
+ node->fingers[finger_index].id = candidate_id;
+ node->fingers[finger_index].mailbox = get_mailbox(candidate_id);
+ INFO2("My new finger #%d is %d", finger_index, candidate_id);
+ print_finger_table(node);
+
+ if (node->pred_id != node->id) { // FIXME: is this necessary?
+ // my predecessor may be concerned too
+ remote_update_finger_table(node, node->pred_id, candidate_id, finger_index);
+ }
+ }
}
-/*
- * Fin successor id : used to fix finger list
+
+/**
+ * \brief Tells a remote node that a node may have became its new finger.
+ * \param ask_to_id id of the remote node to update
+ * \param candidate_id id of the node that may be a new finger of the remote node
+ * \param finger_index index of the finger to update
*/
-finger_elem find_finger_elem(data_node* n_data, int id)
+static void remote_update_finger_table(node_t node, int ask_to_id, int candidate_id, int finger_index)
{
- //if(id >= n_data->id && id <= n_data->fingers[0].id)
- if (is_in_interval(id,n_data->id,n_data->fingers[0].id))
- return n_data->fingers[0];
- //else
- //return find_finger_elem(...,id);
+ task_data_t req_data = xbt_new0(s_task_data_t, 1);
+ req_data->request_id = candidate_id;
+ req_data->request_finger = finger_index;
+ req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
+
+ // send a "Update Finger" request to ask_to_id
+ INFO3("Sending an 'Update Finger' request to %d: his finger #%d may be %d now", ask_to_id, finger_index, candidate_id);
+ m_task_t task = MSG_task_create("Update Finger", 1000, 5000, req_data);
+ char* mailbox = get_mailbox(ask_to_id);
+ msg_comm_t comm = MSG_task_isend(task, mailbox);
+ xbt_dynar_push(node->comms, &comm);
+ xbt_free(mailbox);
+}
+/**
+ * \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
+ */
+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_finger(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
+ */
+static int remote_find_successor(node_t node, int ask_to, int id)
+{
+ s_task_data_t req_data;
+ char* mailbox = bprintf("%s Find Successor", node->mailbox);
+ req_data.request_id = id;
+ req_data.answer_to = mailbox;
+ req_data.issuer_host_name = MSG_host_get_name(MSG_host_self());
+
+ // send a "Find Successor" request to ask_to_id
+ INFO2("Sending a 'Find Successor' request to %d for key %d", ask_to, id);
+ m_task_t task = MSG_task_create("Find Successor", 1000, 5000, &req_data);
+ MSG_task_send(task, get_mailbox(ask_to));
+
+ // receive the answer
+ task = NULL;
+ MSG_task_receive(&task, req_data.answer_to);
+ task_data_t ans_data;
+ ans_data = MSG_task_get_data(task);
+ int successor = ans_data->answer_id;
+ xbt_free(mailbox);
+ INFO2("Received the answer to my Find Successor request: the successor of key %d is %d", id, successor);
+
+ return successor;
}
-/** Test function */
-MSG_error_t test_all(const char *platform_file,
- const char *application_file)
+/**
+ * \brief Makes the current node find the predecessor node of an id.
+ * \param node the current node
+ * \param id the id to find
+ * \return the id of the predecessor node
+ */
+static int find_predecessor(node_t node, int id)
{
- MSG_error_t res = MSG_OK;
+ if (node->id == node->fingers[0].id) {
+ // I am the only node in the system
+ return node->id;
+ }
- /* MSG_config("workstation/model","KCCFLN05"); */
- { /* Simulation setting */
- MSG_set_channel_number(0);
- MSG_create_environment(platform_file);
+ if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
+ return node->id;
+ }
+ int ask_to = closest_preceding_finger(node, id);
+ return remote_find_predecessor(node, ask_to, id);
+}
+
+/**
+ * \brief Asks another node the predecessor 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 predecessor node
+ */
+static int remote_find_predecessor(node_t node, int ask_to, int id)
+{
+ s_task_data_t req_data;
+ char* mailbox = bprintf("%s Find Predecessor", node->mailbox);
+ req_data.request_id = id;
+ req_data.answer_to = mailbox;
+ req_data.issuer_host_name = MSG_host_get_name(MSG_host_self());
+
+ // send a "Find Predecessor" request to ask_to
+ INFO2("Sending a 'Find Predecessor' request to %d for key %d", ask_to, id);
+ m_task_t task = MSG_task_create("Find Predecessor", 1000, 5000, &req_data);
+ MSG_task_send(task, get_mailbox(ask_to));
+
+ // receive the answer
+ task = NULL;
+ MSG_task_receive(&task, req_data.answer_to);
+ task_data_t ans_data;
+ ans_data = MSG_task_get_data(task);
+ int predecessor = ans_data->answer_id;
+ xbt_free(mailbox);
+ INFO2("Received the answer to my 'Find Predecessor' request: the predecessor of key %d is %d", id, predecessor);
+
+ return predecessor;
+}
+
+/**
+ * \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_finger(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) {
+
+ int x = find_predecessor(node, node->fingers[0].id);
+ if (is_in_interval(x, node->id + 1, node->fingers[0].id)) {
+ xbt_free(node->fingers[0].mailbox);
+ node->fingers[0].id = x;
+ node->fingers[0].mailbox = get_mailbox(x);
+ }
+ remote_notify(node, node->fingers[0].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) {
+
+ if (node->pred_id == node->id
+ || is_in_interval(predecessor_candidate_id, node->pred_id, node->id)) {
+ node->pred_id = predecessor_candidate_id;
+ node->pred_mailbox = get_mailbox(predecessor_candidate_id);
+
+ INFO1("My new predecessor is %d", predecessor_candidate_id);
+ print_finger_table(node);
}
- { /* Application deployment */
- MSG_function_register("node",node);
- MSG_launch_application(application_file);
+ else {
+ INFO1("I don't have to change my predecessor to %d", predecessor_candidate_id);
}
- res = MSG_main();
- INFO1("Simulation time %g", MSG_get_clock());
+}
- return res;
-} /* end_of_test_all */
+/**
+ * \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->request_id = predecessor_candidate_id;
+ req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
+
+ // send a "Notify" request to notify_id
+ INFO1("Sending a 'Notify' request to %d", notify_id);
+ m_task_t task = MSG_task_create("Notify", 1000, 5000, req_data);
+ char* mailbox = get_mailbox(notify_id);
+ msg_comm_t comm = MSG_task_isend(task, mailbox);
+ xbt_dynar_push(node->comms, &comm);
+ xbt_free(mailbox);
+}
-/** Main function */
+/**
+ * \brief Asks a node to take some of its keys.
+ * \param node the current node, which has just joined the system
+ * \param take_from_id id of a node who may have keys to give to the current node
+ */
+static void remote_move_keys(node_t node, int take_from_id) {
+ // TODO
+}
+
+/**
+ * \brief Main function.
+ */
int main(int argc, char *argv[])
{
- MSG_error_t res = MSG_OK;
-
- MSG_global_init(&argc, argv);
if (argc < 3) {
printf("Usage: %s platform_file deployment_file\n", argv[0]);
- printf("example: %s msg_platform.xml msg_deployment.xml\n", argv[0]);
+ printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
exit(1);
}
- res = test_all(argv[1], argv[2]);
+
+ MSG_global_init(&argc, argv);
+
+ const char* platform_file = argv[1];
+ const char* application_file = argv[2];
+
+ /* MSG_config("workstation/model","KCCFLN05"); */
+ MSG_set_channel_number(0);
+ MSG_create_environment(platform_file);
+
+ MSG_function_register("node", node);
+ MSG_launch_application(application_file);
+
+ MSG_error_t res = MSG_main();
+ INFO1("Simulation time: %g", MSG_get_clock());
+
MSG_clean();
if (res == MSG_OK)
return 0;
else
return 1;
-} /* end_of_main */
+}
