Working on Chord

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@9103 48e7efb5-ca39-0410-a469-dd3cf9ba447f

diff --git a/examples/msg/chord/chord.c b/examples/msg/chord/chord.c
index 38728bd..e44aed8 100644 (file)
--- a/examples/msg/chord/chord.c
+++ b/examples/msg/chord/chord.c
@@ -5,269 +5,349 @@
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
 #include <stdio.h>
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
 #include <stdio.h>

-#include <math.h>

 #include "msg/msg.h"
 #include "msg/msg.h"

-#include "xbt/sysdep.h"         /* calloc, printf */
-
-/* Create a log channel to have nice outputs. */

 #include "xbt/log.h"
 #include "xbt/asserts.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");
                              "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;
+#define NB_BITS 6
+#define NB_KEYS 64

 
 

-/*
- * Node Data
+/**
+ * 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;
+typedef struct finger {
+  int id;
+  const char* mailbox;
+} s_finger_t, *finger_t;

 
 

+/**
+ * Node data.
+ */
+typedef struct node {
+  int id;                                 // my id
+  const char* mailbox;
+  s_finger_t fingers[NB_BITS];            // finger table (fingers[0] is my successor)
+  int pred_id;                            // predecessor id
+  const char* pred_mailbox;
+} s_node_t, *node_t;
+
+/**
+ * Task data
+ */
+typedef struct task_data {
+  int request_id;
+  int request_finger;
+  int answer_id;
+  const char* answer_to;
+} 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);
+
+// process functions

 static int node(int argc, char *argv[]);
 static int sender(int argc,char *argv[]);
 static int node(int argc, char *argv[]);
 static int sender(int argc,char *argv[]);

-static void find_successor_node(data_node *my_data, m_task_t join_task);
-static int find_successor(data_node* my_data, int id);
-static const char* find_closest_preceding(data_node* n_node, int id); //return a mailbox
-static int get_successor_id(m_host_t);

 
 

-static MSG_error_t test_all(const char *platform_file,
-                            const char *application_file);
-static void init_finger_table(data_node *data, int known_id);
+// 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);
+
+// 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(node_t);
+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(int ask_to_id, int candidate_id, int finger_index);
+
+//static void find_successor_node(node_t my_data, m_task_t join_task);
+
+/**
+ * \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) {

 
 

-static int is_in_interval(unsigned int id, unsigned int start, unsigned int end) {
+  // make sure id >= 0
+  while (id < 0) {
+    id += NB_KEYS;
+  }
+
+  // make sure id < NB_KEYS
+  id = id % NB_KEYS;

 
 

-  id = id % CHORD_NB_KEYS;
-  start = start % CHORD_NB_KEYS;
-  end = end % CHORD_NB_KEYS;
+  return id;
+}

 
 

-  /* make sure end >= start and id >= start */
+/**
+ * \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);
+
+  // make sure end >= start and id >= start

   if (end < start) {
   if (end < start) {

-    end += CHORD_NB_KEYS;
+    end += NB_KEYS;

   }
 
   if (id < start) {
   }
 
   if (id < start) {

-    id += CHORD_NB_KEYS;
+    id += NB_KEYS;

   }
 
   }
 

-  return id < end;
+  return id <= end;

 }
 
 }
 

-/*
- * Node Function
+/**
+ * \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) {

 
 

-/*<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;
+  return bprintf("mailbox%d", node_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[])
 {
 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;
-       }
+  xbt_assert0(argc == 2 || argc == 4, "Wrong number of arguments for this node");

 
 

-       //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;
+  // initialize my node
+  s_node_t node = {0};
+  node.id = atoi(argv[1]);
+  node.mailbox = get_mailbox(node.id);

 
 

-/*
- * Ring Point Entry Node
+  if (argc == 2) { // first ring
+    initialize_first_node(&node);
+  }
+  else {
+    int known_id = atoi(argv[2]);
+    double sleep_time = atof(argv[3]);
+
+    // 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 (1) {
+
+    m_task_t task = NULL;
+    MSG_error_t res = MSG_task_receive(&task, node.mailbox);
+
+    xbt_assert0(res == MSG_OK, "MSG_task_receive failed");
+
+    // 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")) {
+
+      // 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");
+        MSG_task_send(task, task_data->answer_to);
+      }
+      else {
+       // otherwise, forward the request to the closest preceding finger in my table
+       int closest = closest_preceding_finger(&node, task_data->request_id);
+       MSG_task_send(task, get_mailbox(closest));
+      }
+    }
+    /*
+    else if (!strcmp(task_name, "Find Successor Answer")) {
+
+    }
+    */
+    else if (!strcmp(task_name, "Find Predecessor")) {
+
+      // 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");
+        MSG_task_send(task, task_data->answer_to);
+      }
+      else {
+       // otherwise, forward the request to the closest preceding finger in my table
+       int closest = closest_preceding_finger(&node, task_data->request_id);
+       MSG_task_send(task, get_mailbox(closest));
+      }
+    }
+    /*
+    else if (!strcmp(task_name, "Find Predecessor Answer")) {
+
+    }
+    */
+    else if (!strcmp(task_name, "Update Finger")) {
+      update_finger_table(&node, task_data->request_id, task_data->request_finger);
+    }
+    /*
+    else if (!strcmp(task_name, "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));
+      }
+    }
+    */
+  }
+}
+
+/**
+ * \brief Initializes the current node as the first one of the system.
+ * \param node the current node

  */
  */

-       if (create) // first ring
-       {
-               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);
-                               }
-
-                       }
-               }
-       }
-/*
- * Joining 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 = node->mailbox;
+  }
+  node->pred_id = node->id;
+  node->pred_mailbox = node->mailbox;
+}
+
+/**
+ * \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

  */
  */

-       else if(!create)
-       {
-               //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...???§§§§**************************
-
-                       }
-                       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));
-                               }
-                       }
-               }
-       }
-       return 0;
+static void join(node_t node, int known_id)
+{
+  initialize_finger_table(node, known_id); // determine my fingers, asking to known_id
+  notify(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 sucessor

 }
 
 /*
 }
 
 /*

- * Initializes 
+ * \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 init_finger_table(data_node *node, int known_id) {
+static void initialize_finger_table(node_t node, int known_id)
+{
+ int my_id = node->id;
+ int i;
+ int pow = 1; // 2^i

 
   // ask known_id who is my immediate successor
 
   // ask known_id who is my immediate successor

-//  data->fingers[0].id = remote_find_successor(known_id, data->id + 1);
+  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);
+  }

 }
 
 }
 

-/*
- *
+/**
+ * \brief Notifies some nodes that the current node may have became their finger.
+ * \param node the current node, which has just joined the system

  */
  */

-void find_successor_node(data_node* n_data,m_task_t join_task)  //use all data
+static void notify(node_t node)
+{
+  int i, pred_id;
+  int pow = 1;
+  for (i = 0; i < NB_KEYS; i++) {
+    // find the closest node whose finger #i can be me
+    pred_id = find_predecessor(node, node->id - pow);
+    remote_update_finger_table(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)
+{
+  if (is_in_interval(candidate_id, node->id, node->fingers[finger_index].id - 1)) {
+
+    // candidate_id is my new finger
+    node->fingers[finger_index].id = candidate_id;
+    node->fingers[finger_index].mailbox = get_mailbox(candidate_id);
+
+    // my predecessor may be concerned too
+    remote_update_finger_table(node->pred_id, candidate_id, finger_index);
+  }
+}
+
+/**
+ * \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
+ */
+static void remote_update_finger_table(int ask_to_id, int candidate_id, int finger_index)
+{
+  s_task_data_t req_data;
+  req_data.request_id = candidate_id;
+  req_data.request_finger = finger_index;
+
+  // send a "Update Finger" request to ask_to_id
+  m_task_t task = MSG_task_create("Update Finger", 1000, 5000, &req_data);
+  MSG_task_send(task, get_mailbox(ask_to_id));
+}
+
+/* deprecated version where the remote host modifies the issuer's node data
+static void find_successor_node(node_t n_data,m_task_t join_task)  //use all data

 {
        //get recv data
 {
        //get recv data

-       data_node *recv_data = (data_node*)MSG_task_get_data(join_task);
+       node_t recv_data = (node_t)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))
        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))


@@ -299,69 +379,157 @@ void find_successor_node(data_node* n_data,m_task_t join_task)  //use all data
                MSG_task_send(join_task,closest_preceding_mailbox);
        }
 }
                MSG_task_send(join_task,closest_preceding_mailbox);
        }
 }

+*/

 
 

-const char* find_closest_preceding(data_node* n_node,int id)
+/**
+ * \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)

 {
 {

-       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;
-       }
+  // is my successor the successor?
+  if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
+    return node->fingers[0].id;
+  }

 
 

-       return n_node->mailbox; // !!!!!!!!!!!!!!
+  // otherwise, ask the closest preceding finger in my table
+  int closest = closest_preceding_finger(node, id);
+  return remote_find_successor(node, closest, id);

 }
 }

-/*
- * Fin successor id : used to fix finger list
+
+/**
+ * \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 find_successor(data_node* n_data, int id)
+static int remote_find_successor(node_t node, int ask_to, int id)

 {
 {

-       if (is_in_interval(id,n_data->id,n_data->fingers[0].id))
-               return n_data->fingers[0].id;
-       else
-           return 0;
-
+  s_task_data_t req_data;
+  req_data.request_id = id;
+  req_data.answer_to = node->mailbox;
+
+  // send a "Find Successor" request to 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, node->mailbox); // FIXME: don't receive here other messages than the excepted one
+  task_data_t ans_data;
+  ans_data = MSG_task_get_data(task);
+  int successor = ans_data->answer_id;
+
+  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;
-
-  /* MSG_config("workstation/model","KCCFLN05"); */
-  {                             /*  Simulation setting */
-    MSG_set_channel_number(0);
-    MSG_create_environment(platform_file);
+  if (node->id == node->fingers[0].id) {
+    // I am the only node in the system
+    return node->id;
+  }

 
 

+  if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
+    return node->id;

   }
   }

-  {                             /*   Application deployment */
-       MSG_function_register("node",node);
-    MSG_launch_application(application_file);
+  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;
+  req_data.request_id = id;
+  req_data.answer_to = node->mailbox;
+
+  // send a "Find Predecessor" request to ask_to
+  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, node->mailbox); // FIXME: don't receive here other messages than the excepted one
+  task_data_t ans_data;
+  ans_data = MSG_task_get_data(task);
+  int predecessor = ans_data->answer_id;
+
+  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;
+    }

   }
   }

-  res = MSG_main();
-  INFO1("Simulation time %g", MSG_get_clock());
+  return node->id;
+}

 
 

-  return res;
-}                               /* end_of_test_all */
+/**
+ * \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
+}

 
 

-/** Main function */
+/**
+ * \brief Main function.
+ */

 int main(int argc, char *argv[])
 {
 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]);
   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);
   }
     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;
   MSG_clean();
 
   if (res == MSG_OK)
     return 0;
   else
     return 1;

-}                               /* end_of_main */
+}

diff --git a/examples/msg/chord/chord.xml b/examples/msg/chord/chord.xml
index 5727b6b..18ffb26 100644 (file)
--- a/examples/msg/chord/chord.xml
+++ b/examples/msg/chord/chord.xml
@@ -3,72 +3,50 @@
 <platform version="3">
 
   <process host="Gatien" function="node">
 <platform version="3">
 
   <process host="Gatien" function="node">

-    <argument value="48"/>           <!-- my id -->
-    <argument value="40"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>       <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="48"/>        <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="13"/>         <!--time to sleep before it starts-->
+    <argument value="13"/>        <!-- time to sleep before it starts-->

 
   </process>
 
   <process host="McGee" function="node">
 
   </process>
 
   <process host="McGee" function="node">

-    <argument value="42"/>           <!-- my id -->
-    <argument value="41"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>           <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="42"/>        <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="11"/>         <!--time to sleep before it starts-->
+    <argument value="11"/>        <!-- time to sleep before it starts-->

   </process>
 
   <process host="iRMX" function="node">
   </process>
 
   <process host="iRMX" function="node">

-    <argument value="38"/>       <!-- my id -->
-    <argument value="43"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>           <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="38"/>        <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="9"/>         <!--time to sleep before it starts-->
+    <argument value="9"/>         <!-- time to sleep before it starts-->

   </process>
 
   <process host="Geoff" function="node">
   </process>
 
   <process host="Geoff" function="node">

-    <argument value="32"/>           <!-- my id -->
-    <argument value="44"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>           <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="32"/>        <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="7"/>         <!--time to sleep before it starts-->
+    <argument value="7"/>         <!-- time to sleep before it starts-->

   </process>
 
   <process host="TeX" function="node">
   </process>
 
   <process host="TeX" function="node">

-    <argument value="21"/>           <!-- my id -->
-    <argument value="45"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>    <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="21"/>        <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="5"/>         <!--time to sleep before it starts-->
+    <argument value="5"/>         <!-- time to sleep before it starts-->

   </process>
 
   <process host="Jean_Yves" function="node">
   </process>
 
   <process host="Jean_Yves" function="node">

-    <argument value="14"/>           <!-- my id -->
-    <argument value="46"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>       <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="14"/>        <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="3"/>         <!--time to sleep before it starts-->
+    <argument value="3"/>         <!-- time to sleep before it starts-->

   </process>
 
   <process host="Boivin" function="node">
   </process>
 
   <process host="Boivin" function="node">

-    <argument value="8"/>            <!-- my id -->
-    <argument value="47"/>         <!-- my mailbox -->
-    <argument value="Jacquelin"/>    <!-- known host -->
-    <argument value="48"/>         <!-- known mailbox -->
+    <argument value="8"/>         <!-- my id -->

     <argument value="1"/>         <!-- known id -->
     <argument value="1"/>         <!-- known id -->

-    <argument value="1"/>         <!--time to sleep before it starts-->
+    <argument value="1"/>         <!-- time to sleep before it starts-->

   </process>
 
   <process host="Jacquelin" function="node">
   </process>
 
   <process host="Jacquelin" function="node">

-    <argument value="1"/>            <!-- my id -->
-    <argument value="48"/>         <!-- my mailbox -->
+    <argument value="1"/>         <!-- my id -->

   </process>
 
 </platform>
   </process>
 
 </platform>