+/* Copyright (c) 2012. 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 "kademlia.h"
+#include "node.h"
+#include "task.h"
+
+#include "msg/msg.h"
+#include "xbt/log.h"
+#include "xbt/asserts.h"
+/** @addtogroup MSG_examples
+ * <b>kademlia/kademlia.c: Kademlia protocol</b>
+ * Implements the Kademlia protocol, using 32 bits identifiers.
+ */
+ XBT_LOG_NEW_DEFAULT_CATEGORY(msg_kademlia,
+ "Messages specific for this msg example");
+
+extern long unsigned int smx_total_comms;
+
+/**
+ * \brief Node function
+ * Arguments :
+ * - my node ID
+ * - the ID of the person I know in the system (or not)
+ * - Time before I leave the system because I'm bored
+ */
+int node(int argc, char *argv[]) {
+ unsigned int join_sucess = 1, deadline;
+ xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
+ /* Node initialization */
+ unsigned int id = atoi(argv[1]);;
+ node_t node = node_init(id);
+
+ if (argc == 4) {
+ XBT_INFO("Hi, I'm going to join the network !");
+ unsigned int id_known = (unsigned int)atoi(argv[2]);
+ join_sucess = join(node,id_known);
+ deadline = atoi(argv[3]);
+ }
+ else {
+ deadline = atoi(argv[2]);
+ XBT_INFO("Hi, I'm going to create the network with id %s !",node->mailbox);
+ node_routing_table_update(node,node->id);
+ }
+ if (join_sucess) {
+ XBT_VERB("Ok, I'm joining the network with id %s",node->mailbox);
+ //We start the main loop
+ main_loop(node,deadline);
+ }
+ else {
+ XBT_INFO("I couldn't join the network :(");
+ }
+ XBT_DEBUG("I'm leaving the network");
+ XBT_INFO("%d/%d FIND_NODE have succeeded",node->find_node_success,node->find_node_success + node->find_node_failed);
+ node_free(node);
+
+ return 0;
+}
+/**
+ * Main loop for the process
+ */
+void main_loop(node_t node, unsigned int deadline) {
+ double next_lookup_time = MSG_get_clock() + random_lookup_interval;
+ XBT_VERB("Main loop start");
+ while (MSG_get_clock() < deadline) {
+
+ if (node->receive_comm == NULL) {
+ node->task_received = NULL;
+ node->receive_comm = MSG_task_irecv(&node->task_received,node->mailbox);
+ }
+ if (node->receive_comm) {
+ if (!MSG_comm_test(node->receive_comm)) {
+ /* We search for a pseudo random node */
+ if (MSG_get_clock() >= next_lookup_time) {
+ random_lookup(node);
+ next_lookup_time += random_lookup_interval;
+ }
+ else {
+ //Didn't get a task: sleep for a while...
+ MSG_process_sleep(1);
+ }
+ }
+ else {
+ //There has been a transfer, we need to handle it !
+ msg_error_t status = MSG_comm_get_status(node->receive_comm);
+ MSG_comm_destroy(node->receive_comm);
+ node->receive_comm = NULL;
+
+ if (status == MSG_OK) {
+ xbt_assert( (node->task_received != NULL), "We received an incorrect task");
+ handle_task(node,node->task_received);
+ }
+ else {
+ xbt_assert((MSG_comm_get_task(node->receive_comm) == NULL),"Comm failed but received a task.");
+ XBT_DEBUG("Nevermind, the communication has failed.");
+ }
+ }
+ }
+ else {
+ //Didn't get a comm: sleep.
+ MSG_process_sleep(1);
+ }
+ }
+ //Cleanup the receiving communication.
+ if (node->receive_comm != NULL ) {
+ if (MSG_comm_test(node->receive_comm) && MSG_comm_get_status(node->receive_comm) == MSG_OK) {
+ task_free(MSG_comm_get_task(node->receive_comm));
+ }
+ MSG_comm_destroy(node->receive_comm);
+ }
+}
+/**
+ * Tries to join the network
+ * @param node node data
+ * @param id_known id of the node I know in the network.
+ */
+unsigned int join(node_t node, unsigned int id_known) {
+ answer_t node_list;
+ msg_error_t status;
+ unsigned int trial = 0;
+ unsigned int i, answer_got = 0;
+
+ /* Add the guy we know to our routing table and ourselves. */
+ node_routing_table_update(node,node->id);
+ node_routing_table_update(node,id_known);
+
+ /* First step: Send a "FIND_NODE" request to the node we know */
+ send_find_node(node,id_known,node->id);
+ do {
+ if (node->receive_comm == NULL) {
+ node->task_received = NULL;
+ node->receive_comm = MSG_task_irecv(&node->task_received,node->mailbox);
+ }
+ if (node->receive_comm) {
+ if (MSG_comm_test(node->receive_comm)) {
+ status = MSG_comm_get_status(node->receive_comm);
+ MSG_comm_destroy(node->receive_comm);
+ node->receive_comm = NULL;
+ if (status == MSG_OK) {
+ XBT_DEBUG("Received an answer from the node I know.");
+ answer_got = 1;
+ //retrieve the node list and ping them.
+ task_data_t data = MSG_task_get_data(node->task_received);
+ xbt_assert( (data != NULL), "Null data received");
+ if (data->type == TASK_FIND_NODE_ANSWER) {
+ node_contact_t contact;
+ node_list = data->answer;
+ xbt_dynar_foreach(node_list->nodes,i, contact) {
+ node_routing_table_update(node,contact->id);
+ //ping(node,contact->id);
+ }
+ task_free(node->task_received);
+ }
+ else {
+ handle_task(node,node->task_received);
+ }
+ }
+ else {
+ trial++;
+ }
+ }
+ else {
+ MSG_process_sleep(1);
+ }
+ }
+ else {
+ MSG_process_sleep(1);
+ }
+ } while (answer_got == 0 && trial < max_join_trials);
+ /* Second step: Send a FIND_NODE to a a random node in buckets */
+ unsigned int bucket_id = routing_table_find_bucket(node->table,id_known)->id;
+ for (i = 0; ((bucket_id -i) > 0 || (bucket_id + i) <= identifier_size) && i < JOIN_BUCKETS_QUERIES; i++) {
+ if (bucket_id - i > 0) {
+ unsigned int id_in_bucket = get_id_in_prefix(node->id,bucket_id - i);
+ find_node(node,id_in_bucket,0);
+ }
+ if (bucket_id + i <= identifier_size) {
+ unsigned int id_in_bucket = get_id_in_prefix(node->id,bucket_id + i);
+ find_node(node,id_in_bucket,0);
+ }
+ }
+ return answer_got;
+}
+/**
+ * Send a request to find a node in the node routing table.
+ * @brief node our node data
+ * @brief id_to_find the id of the node we are trying to find
+ */
+unsigned int find_node(node_t node, unsigned int id_to_find, unsigned int count_in_stats) {
+
+ unsigned int i = 0;
+ unsigned int queries, answers;
+ unsigned int destination_found = 0;
+ unsigned int nodes_added = 0;
+ double time_beginreceive;
+ double timeout, global_timeout = MSG_get_clock() + find_node_global_timeout;
+ unsigned int steps = 0;
+
+ xbt_assert( (id_to_find >= 0), "Id supplied incorrect");
+
+ /* First we build a list of who we already know */
+ answer_t node_list = node_find_closest(node,id_to_find);
+ xbt_assert((node_list != NULL),"node_list incorrect");
+
+ XBT_DEBUG("Doing a FIND_NODE on %d", id_to_find);
+
+ msg_error_t status;
+
+ /* Ask the nodes on our list if they have information about
+ * the node we are trying to find */
+
+ do {
+ answers = 0;
+ queries = send_find_node_to_best(node,node_list);
+ nodes_added = 0;
+ timeout = MSG_get_clock() + find_node_timeout;
+ steps++;
+ time_beginreceive = MSG_get_clock();
+ do {
+ if (node->receive_comm == NULL) {
+ node->task_received = NULL;
+ node->receive_comm = MSG_task_irecv(&node->task_received,node->mailbox);
+ }
+ if (node->receive_comm) {
+ if (MSG_comm_test(node->receive_comm)) {
+ status = MSG_comm_get_status(node->receive_comm);
+ MSG_comm_destroy(node->receive_comm);
+ node->receive_comm = NULL;
+ if (status == MSG_OK) {
+ xbt_assert( (node->task_received != NULL), "Invalid task received");
+ //Figure out if we received an answer or something else
+ task_data_t data = MSG_task_get_data(node->task_received);
+ xbt_assert( (data != NULL), "No data in the task");
+
+ //Check if what we have received is what we are looking for.
+ if (data->type == TASK_FIND_NODE_ANSWER && data->answer->destination_id == id_to_find) {
+ //Handle the answer
+ node_routing_table_update(node,data->sender_id);
+ node_contact_t contact;
+ xbt_dynar_foreach(node_list->nodes,i, contact) {
+ node_routing_table_update(node,contact->id);
+ }
+ answers++;
+
+ nodes_added = answer_merge(node_list,data->answer);
+ XBT_DEBUG("Received an answer from %s (%s) with %ld nodes on it",data->answer_to,data->issuer_host_name,xbt_dynar_length(data->answer->nodes));
+
+ task_free(node->task_received);
+ }
+ else {
+ handle_task(node,node->task_received);
+ //Update the timeout if we didn't have our answer
+ timeout += MSG_get_clock() - time_beginreceive;
+ time_beginreceive = MSG_get_clock();
+ }
+ }
+ }
+ else {
+ MSG_process_sleep(1);
+ }
+ }
+ else {
+ MSG_process_sleep(1);
+ }
+ } while (MSG_get_clock() < timeout && answers < queries) ;
+ destination_found = answer_destination_found(node_list);
+ } while (!destination_found && (nodes_added > 0 || answers == 0) && MSG_get_clock() < global_timeout && steps < MAX_STEPS);
+ if (destination_found) {
+ if (count_in_stats)
+ node->find_node_success++;
+ if (queries > 4)
+ XBT_VERB("FIND_NODE on %d success in %d steps",id_to_find,steps);
+ node_routing_table_update(node,id_to_find);
+ }
+ else {
+ if (count_in_stats) {
+ node->find_node_failed++;
+ XBT_VERB("%d not found in %d steps",id_to_find,steps);
+ }
+ }
+ answer_free(node_list);
+ return destination_found;
+}
+/**
+ * Pings a node in the system to see if it is online.
+ * @param node Our node data
+ * @param id_to_ping the id of a node we want to see if it is online.
+ * @return if the ping succeded or not.
+ */
+unsigned int ping(node_t node, unsigned int id_to_ping) {
+ char mailbox[MAILBOX_NAME_SIZE];
+ sprintf(mailbox,"%d",id_to_ping);
+
+ unsigned int destination_found = 0;
+ unsigned int timeout = MSG_get_clock() + ping_timeout;
+
+ msg_task_t ping_task = task_new_ping(node->id,node->mailbox,MSG_host_get_name(MSG_host_self()));
+ msg_task_t task_received = NULL;
+
+ XBT_VERB("PING %d",id_to_ping);
+
+ //Check that we aren't trying to ping ourselves
+ if (id_to_ping == node->id) {
+ return 1;
+ }
+
+ /* Sending the ping task */
+ MSG_task_dsend(ping_task,mailbox,task_free_v);
+ do
+ {
+ task_received = NULL;
+ msg_error_t status = MSG_task_receive_with_timeout(&task_received,node->mailbox,ping_timeout);
+ if (status == MSG_OK) {
+ xbt_assert( (task_received != NULL), "Invalid task received");
+ //Checking if it's what we are waiting for or not.
+ task_data_t data = MSG_task_get_data(task_received);
+ xbt_assert( (data != NULL) ,"didn't receive any data...");
+ if (data->type == TASK_PING_ANSWER && id_to_ping == data->sender_id) {
+ XBT_VERB("Ping to %s succeeded",mailbox);
+ node_routing_table_update(node,data->sender_id);
+ destination_found = 1;
+ task_free(task_received);
+ }
+ else {
+ //If it's not our answer, we answer the query anyway.
+ handle_task(node,task_received);
+ }
+ }
+ } while (destination_found == 0 && MSG_get_clock() < timeout);
+
+ if (MSG_get_clock() >= timeout) {
+ XBT_DEBUG("Ping to %s has timeout.",mailbox);
+ return 0;
+ }
+ if (destination_found == -1) {
+ XBT_DEBUG("It seems that %s is offline...",mailbox);
+ return 0;
+ }
+ return 1;
+}
+/**
+ * Does a pseudo-random lookup for someone in the system
+ * @param node caller node data
+ */
+void random_lookup(node_t node) {
+ unsigned int id_to_look = RANDOM_LOOKUP_NODE; //Totally random.
+ /* TODO: Use some pseudorandom generator like RngStream. */
+ XBT_DEBUG("I'm doing a random lookup");
+ find_node(node,id_to_look,1);
+}
+/**
+ * @brief Send a "FIND_NODE" to a node
+ * @param node sender node data
+ * @param id node we are querying
+ * @param destination node we are trying to find.
+ */
+void send_find_node(node_t node, unsigned int id, unsigned int destination) {
+ char mailbox[MAILBOX_NAME_SIZE];
+ /* Gets the mailbox to send to */
+ get_node_mailbox(id,mailbox);
+ /* Build the task */
+ msg_task_t task = task_new_find_node(node->id,destination,node->mailbox,MSG_host_get_name(MSG_host_self()));
+ /* Send the task */
+ xbt_assert( (task != NULL), "Trying to send a NULL task.");
+ MSG_task_dsend(task,mailbox,task_free_v);
+ XBT_VERB("Asking %s for its closest nodes",mailbox);
+}
+/**
+ * Sends to the best "kademlia_alpha" nodes in the "node_list" array a "FIND_NODE" request, to ask them for their best nodes
+ */
+unsigned int send_find_node_to_best(node_t node, answer_t node_list) {
+ unsigned int i = 0, j = 0;
+ unsigned int destination = node_list->destination_id;
+ node_contact_t node_to_query;
+ while (j < kademlia_alpha && i < node_list->size) { /* We need to have at most "kademlia_alpha" requets each time, according to the protocol */
+ /* Gets the node we want to send the query to */
+ node_to_query = xbt_dynar_get_as(node_list->nodes,i,node_contact_t);
+ if (node_to_query->id != node->id) { /* No need to query ourselves */
+ send_find_node(node,node_to_query->id,destination);
+ j++;
+ }
+ i++;
+ }
+ return i;
+}
+/**
+ * \brief Handles an incomming received task
+ */
+void handle_task(node_t node, msg_task_t task) {
+ task_data_t data = MSG_task_get_data(task);
+ xbt_assert( (data != NULL), "Received NULL data");
+ //Adding/updating the guy to our routing table
+ node_routing_table_update(node,data->sender_id);
+ switch (data->type) {
+ case TASK_FIND_NODE:
+ handle_find_node(node,data);
+ break;
+ case TASK_FIND_NODE_ANSWER:
+ XBT_DEBUG("Received a wrong answer for a FIND_NODE");
+ break;
+ case TASK_PING:
+ handle_ping(node,data);
+ break;
+ default:
+
+ break;
+ }
+ task_free(task);
+}
+/**
+ * \brief Handles the answer to an incomming "find_node" task
+ */
+void handle_find_node(node_t node, task_data_t data) {
+ XBT_VERB("Received a FIND_NODE from %s (%s), he's trying to find %d",data->answer_to,data->issuer_host_name,data->destination_id);
+ //Building the answer to the request
+ answer_t answer = node_find_closest(node,data->destination_id);
+ //Building the task to send
+ msg_task_t task = task_new_find_node_answer(node->id,data->destination_id,answer,node->mailbox,MSG_host_get_name(MSG_host_self()));
+ //Sending the task
+ MSG_task_dsend(task,data->answer_to,task_free_v);
+}
+/**
+ * \brief handles the answer to a ping
+ */
+void handle_ping(node_t node, task_data_t data) {
+ XBT_VERB("Received a PING request from %s (%s)",data->answer_to,data->issuer_host_name);
+ //Building the answer to the request
+ msg_task_t task = task_new_ping_answer(node->id,data->answer_to,MSG_host_get_name(MSG_host_self()));
+
+ MSG_task_dsend(task,data->answer_to,task_free_v);
+}
+/**
+ * \brief Main function
+ */
+int main(int argc, char *argv[]) {
+
+ MSG_init(&argc, argv);
+
+ /* Check the arguments */
+ if (argc < 3) {
+ printf("Usage: %s platform_file deployment_file \n",argv[0]);
+ return -1;
+ }
+
+ const char *platform_file = argv[1];
+ const char *deployment_file = argv[2];
+
+ MSG_create_environment(platform_file);
+
+ MSG_function_register("node",node);
+ MSG_launch_application(deployment_file);
+
+ msg_error_t res = MSG_main();
+
+ XBT_CRITICAL("Messages created: %ld", smx_total_comms);
+ XBT_INFO("Simulated time: %g", MSG_get_clock());
+ MSG_clean();
+
+ if ( res == MSG_OK)
+ return 0;
+ else
+ return 1;
+}
