+
/* Copyright (c) 2010. The SimGrid Team.
* All rights reserved. */
*/
typedef struct finger {
int id;
- const char* mailbox;
+ char* mailbox;
} s_finger_t, *finger_t;
/**
*/
typedef struct node {
int id; // my id
- const char* mailbox;
+ char* mailbox;
s_finger_t fingers[NB_BITS]; // finger table (fingers[0] is my successor)
int pred_id; // predecessor id
- const char* pred_mailbox;
+ char* pred_mailbox;
+ xbt_dynar_t comms; // current communications to finish
} s_node_t, *node_t;
/**
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[]);
-static int sender(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_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 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(int ask_to_id, int candidate_id, int finger_index);
-
-//static void find_successor_node(node_t my_data, m_task_t join_task);
+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[
while (id < 0) {
id += NB_KEYS;
}
-
// make sure id < NB_KEYS
id = id % NB_KEYS;
return bprintf("mailbox%d", node_id);
}
+/**
+ * \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);
+}
+
/**
* \brief Node Function
* Arguments:
*/
int node(int argc, char *argv[])
{
- xbt_assert0(argc == 2 || argc == 4, "Wrong number of arguments for this node");
+ double init_time = MSG_get_clock();
+ msg_comm_t comm = NULL;
+ int i;
+ char* mailbox;
+ double deadline;
+
+ 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 == 2) { // first ring
+ 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);
join(&node, known_id);
}
- while (1) {
+ 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(&task, node.mailbox);
+ MSG_error_t res = MSG_task_receive_with_timeout(&task, node.mailbox,45); // FIXME >> find the right timeout !!
- xbt_assert0(res == MSG_OK, "MSG_task_receive failed");
+ 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");
- MSG_task_send(task, task_data->answer_to);
+ 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);
- MSG_task_send(task, get_mailbox(closest));
+ 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 Successor Answer")) {
- }
- */
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");
- MSG_task_send(task, task_data->answer_to);
+ 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);
- MSG_task_send(task, get_mailbox(closest));
+ 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, "Find Predecessor Answer")) {
- }
- */
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, "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));
- }
+ 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);
}
}
int i;
for (i = 0; i < NB_BITS; i++) {
node->fingers[i].id = node->id;
- node->fingers[i].mailbox = node->mailbox;
+ node->fingers[i].mailbox = xbt_strdup(node->mailbox);
}
node->pred_id = node->id;
node->pred_mailbox = node->mailbox;
+ print_finger_table(node);
}
/**
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
+ 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 ...
+}
+/*
+ * \brief Notify msg to tell my successor||predecessor about my departure
+ * \param node the current node
+ */
+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;
+ if( to == 1) // notify my successor
+ {
+ to_mailbox = node->fingers[0].mailbox;
+ INFO1("Telling my Successor about my departure via mailbox %s", to_mailbox);
+ task_name = "Predecessor Leaving";
+
+ }
+ else if(to == -1) // notify my predecessor
+ {
+ 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);
}
/*
*/
static void initialize_finger_table(node_t node, int known_id)
{
- int my_id = node->id;
- int i;
- int pow = 1; // 2^i
+ 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[i + 1].mailbox = get_mailbox(node->fingers[i + 1].id);
}
+
+ node->pred_id = find_predecessor(node, node->id);
+ node->pred_mailbox = get_mailbox(node->pred_id);
+
+ INFO0("Finger table initialized!");
+ print_finger_table(node);
}
/**
* \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(node_t node)
+static void notify_predecessors(node_t node)
{
int i, pred_id;
int pow = 1;
- for (i = 0; i < NB_KEYS; i++) {
+ 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);
- remote_update_finger_table(pred_id, node->id, i);
+ 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
}
}
*/
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)) {
+ int pow = 1;
+ int i;
+ for (i = 0; i < finger_index; i++) {
+ pow = pow << 1;
+ }
+ // 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);
- // my predecessor may be concerned too
- remote_update_finger_table(node->pred_id, candidate_id, finger_index);
+ 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);
+ }
}
}
* \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)
+static void remote_update_finger_table(node_t node, 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;
+ 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
- m_task_t task = MSG_task_create("Update Finger", 1000, 5000, &req_data);
- MSG_task_send(task, get_mailbox(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);
}
-/* 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
- 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))
- {
- 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);
- }
-
- 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);
- }
-}
-*/
-
/**
* \brief Makes the current node find the successor node of an id.
* \param node the current 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 = node->mailbox;
+ 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, node->mailbox); // FIXME: don't receive here other messages than the excepted one
+ 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;
}
+
/**
* \brief Makes the current node find the predecessor node of an id.
* \param node the current 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 = node->mailbox;
+ 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, node->mailbox); // FIXME: don't receive here other messages than the excepted one
+ 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;
}
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);
+ }
+ else {
+ INFO1("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->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);
+}
+
/**
* \brief Asks a node to take some of its keys.
* \param node the current node, which has just joined the system
