1 /* Copyright (c) 2012, 2014-2016. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #include "simgrid/msg.h"
13 #include "xbt/asserts.h"
14 /** @addtogroup MSG_examples
15 * <b>kademlia/kademlia.c: Kademlia protocol</b>
16 * Implements the Kademlia protocol, using 32 bits identifiers.
18 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_kademlia, "Messages specific for this msg example");
20 extern long unsigned int smx_total_comms;
22 /* Main loop for the process */
23 static void main_loop(node_t node, double deadline)
25 double next_lookup_time = MSG_get_clock() + random_lookup_interval;
26 XBT_VERB("Main loop start");
27 while (MSG_get_clock() < deadline) {
29 if (node->receive_comm == NULL) {
30 node->task_received = NULL;
31 node->receive_comm = MSG_task_irecv(&node->task_received, node->mailbox);
33 if (node->receive_comm) {
34 if (!MSG_comm_test(node->receive_comm)) {
35 /* We search for a pseudo random node */
36 if (MSG_get_clock() >= next_lookup_time) {
38 next_lookup_time += random_lookup_interval;
40 //Didn't get a task: sleep for a while...
44 //There has been a transfer, we need to handle it !
45 msg_error_t status = MSG_comm_get_status(node->receive_comm);
46 MSG_comm_destroy(node->receive_comm);
47 node->receive_comm = NULL;
49 if (status == MSG_OK) {
50 xbt_assert((node->task_received != NULL), "We received an incorrect task");
51 handle_task(node, node->task_received);
53 xbt_assert((MSG_comm_get_task(node->receive_comm) == NULL), "Comm failed but received a task.");
54 XBT_DEBUG("Nevermind, the communication has failed.");
58 //Didn't get a comm: sleep.
62 //Cleanup the receiving communication.
63 if (node->receive_comm != NULL) {
64 if (MSG_comm_test(node->receive_comm) && MSG_comm_get_status(node->receive_comm) == MSG_OK) {
65 task_free(MSG_comm_get_task(node->receive_comm));
67 MSG_comm_destroy(node->receive_comm);
71 /** @brief Node function
73 * @param the ID of the person I know in the system (or not)
74 * @param Time before I leave the system because I'm bored
76 static int node(int argc, char *argv[])
78 unsigned int join_sucess = 1;
80 xbt_assert(argc == 3 || argc == 4, "Wrong number of arguments");
81 /* Node initialization */
82 unsigned int id = strtoul(argv[1], NULL, 0);
83 node_t node = node_init(id);
86 XBT_INFO("Hi, I'm going to join the network with id %s", node->mailbox);
87 unsigned int id_known = strtoul(argv[2], NULL, 0);
88 join_sucess = join(node, id_known);
89 deadline = strtod(argv[3], NULL);
91 deadline = strtod(argv[2], NULL);
92 XBT_INFO("Hi, I'm going to create the network with id %s", node->mailbox);
93 node_routing_table_update(node, node->id);
96 XBT_VERB("Ok, I'm joining the network with id %s", node->mailbox);
97 //We start the main loop
98 main_loop(node, deadline);
100 XBT_INFO("I couldn't join the network :(");
102 XBT_DEBUG("I'm leaving the network");
103 XBT_INFO("%d/%d FIND_NODE have succeeded", node->find_node_success, node->find_node_success + node->find_node_failed);
110 * @brief Tries to join the network
111 * @param node node data
112 * @param id_known id of the node I know in the network.
114 unsigned int join(node_t node, unsigned int id_known)
118 unsigned int trial = 0;
119 unsigned int i, answer_got = 0;
121 /* Add the guy we know to our routing table and ourselves. */
122 node_routing_table_update(node, node->id);
123 node_routing_table_update(node, id_known);
125 /* First step: Send a "FIND_NODE" request to the node we know */
126 send_find_node(node, id_known, node->id);
128 if (node->receive_comm == NULL) {
129 node->task_received = NULL;
130 node->receive_comm = MSG_task_irecv(&node->task_received, node->mailbox);
132 if (node->receive_comm) {
133 if (MSG_comm_test(node->receive_comm)) {
134 status = MSG_comm_get_status(node->receive_comm);
135 MSG_comm_destroy(node->receive_comm);
136 node->receive_comm = NULL;
137 if (status == MSG_OK) {
138 XBT_DEBUG("Received an answer from the node I know.");
140 //retrieve the node list and ping them.
141 task_data_t data = MSG_task_get_data(node->task_received);
142 xbt_assert((data != NULL), "Null data received");
143 if (data->type == TASK_FIND_NODE_ANSWER) {
144 node_contact_t contact;
145 node_list = data->answer;
146 xbt_dynar_foreach(node_list->nodes, i, contact) {
147 node_routing_table_update(node, contact->id);
149 task_free(node->task_received);
151 handle_task(node, node->task_received);
157 MSG_process_sleep(1);
160 MSG_process_sleep(1);
162 } while (answer_got == 0 && trial < max_join_trials);
163 /* Second step: Send a FIND_NODE to a a random node in buckets */
164 unsigned int bucket_id = routing_table_find_bucket(node->table, id_known)->id;
165 for (i = 0; ((bucket_id - i) > 0 || (bucket_id + i) <= identifier_size) && i < JOIN_BUCKETS_QUERIES; i++) {
166 if (bucket_id - i > 0) {
167 unsigned int id_in_bucket = get_id_in_prefix(node->id, bucket_id - i);
168 find_node(node, id_in_bucket, 0);
170 if (bucket_id + i <= identifier_size) {
171 unsigned int id_in_bucket = get_id_in_prefix(node->id, bucket_id + i);
172 find_node(node, id_in_bucket, 0);
178 /** @brief Send a request to find a node in the node routing table.
179 * @param node our node data
180 * @param id_to_find the id of the node we are trying to find
182 unsigned int find_node(node_t node, unsigned int id_to_find, unsigned int count_in_stats)
185 unsigned int queries, answers;
186 unsigned int destination_found = 0;
187 unsigned int nodes_added = 0;
188 double time_beginreceive;
189 double timeout, global_timeout = MSG_get_clock() + find_node_global_timeout;
190 unsigned int steps = 0;
192 xbt_assert((id_to_find >= 0), "Id supplied incorrect");
194 /* First we build a list of who we already know */
195 answer_t node_list = node_find_closest(node, id_to_find);
196 xbt_assert((node_list != NULL), "node_list incorrect");
198 XBT_DEBUG("Doing a FIND_NODE on %08x", id_to_find);
202 /* Ask the nodes on our list if they have information about the node we are trying to find */
205 queries = send_find_node_to_best(node, node_list);
207 timeout = MSG_get_clock() + find_node_timeout;
209 time_beginreceive = MSG_get_clock();
211 if (node->receive_comm == NULL) {
212 node->task_received = NULL;
213 node->receive_comm = MSG_task_irecv(&node->task_received, node->mailbox);
215 if (node->receive_comm) {
216 if (MSG_comm_test(node->receive_comm)) {
217 status = MSG_comm_get_status(node->receive_comm);
218 MSG_comm_destroy(node->receive_comm);
219 node->receive_comm = NULL;
220 if (status == MSG_OK) {
221 xbt_assert((node->task_received != NULL), "Invalid task received");
222 //Figure out if we received an answer or something else
223 task_data_t data = MSG_task_get_data(node->task_received);
224 xbt_assert((data != NULL), "No data in the task");
226 //Check if what we have received is what we are looking for.
227 if (data->type == TASK_FIND_NODE_ANSWER && data->answer->destination_id == id_to_find) {
229 node_routing_table_update(node, data->sender_id);
230 node_contact_t contact;
231 xbt_dynar_foreach(node_list->nodes, i, contact) {
232 node_routing_table_update(node, contact->id);
236 nodes_added = answer_merge(node_list, data->answer);
237 XBT_DEBUG("Received an answer from %s (%s) with %ld nodes on it",
238 data->answer_to, data->issuer_host_name, xbt_dynar_length(data->answer->nodes));
240 task_free(node->task_received);
242 handle_task(node, node->task_received);
243 //Update the timeout if we didn't have our answer
244 timeout += MSG_get_clock() - time_beginreceive;
245 time_beginreceive = MSG_get_clock();
249 MSG_process_sleep(1);
252 MSG_process_sleep(1);
254 } while (MSG_get_clock() < timeout && answers < queries);
255 destination_found = answer_destination_found(node_list);
256 } while (!destination_found && (nodes_added > 0 || answers == 0) && MSG_get_clock() < global_timeout
257 && steps < MAX_STEPS);
258 if (destination_found) {
260 node->find_node_success++;
262 XBT_VERB("FIND_NODE on %08x success in %d steps", id_to_find, steps);
263 node_routing_table_update(node, id_to_find);
265 if (count_in_stats) {
266 node->find_node_failed++;
267 XBT_VERB("%08x not found in %d steps", id_to_find, steps);
270 answer_free(node_list);
271 return destination_found;
274 /** @brief Pings a node in the system to see if it is online.
275 * @param node Our node data
276 * @param id_to_ping the id of a node we want to see if it is online.
277 * @return if the ping succeded or not.
279 unsigned int ping(node_t node, unsigned int id_to_ping)
281 char mailbox[MAILBOX_NAME_SIZE + 1];
282 sprintf(mailbox, "%0*x", MAILBOX_NAME_SIZE, id_to_ping);
284 unsigned int destination_found = 0;
285 double timeout = MSG_get_clock() + ping_timeout;
287 msg_task_t ping_task = task_new_ping(node->id, node->mailbox, MSG_host_get_name(MSG_host_self()));
288 msg_task_t task_received = NULL;
290 XBT_VERB("PING %08x", id_to_ping);
292 //Check that we aren't trying to ping ourselves
293 if (id_to_ping == node->id) {
297 /* Sending the ping task */
298 MSG_task_dsend(ping_task, mailbox, task_free_v);
300 task_received = NULL;
302 MSG_task_receive_with_timeout(&task_received, node->mailbox, ping_timeout);
303 if (status == MSG_OK) {
304 xbt_assert((task_received != NULL), "Invalid task received");
305 //Checking if it's what we are waiting for or not.
306 task_data_t data = MSG_task_get_data(task_received);
307 xbt_assert((data != NULL), "didn't receive any data...");
308 if (data->type == TASK_PING_ANSWER && id_to_ping == data->sender_id) {
309 XBT_VERB("Ping to %s succeeded", mailbox);
310 node_routing_table_update(node, data->sender_id);
311 destination_found = 1;
312 task_free(task_received);
314 //If it's not our answer, we answer the query anyway.
315 handle_task(node, task_received);
318 } while (destination_found == 0 && MSG_get_clock() < timeout);
320 if (MSG_get_clock() >= timeout) {
321 XBT_DEBUG("Ping to %s has timeout.", mailbox);
324 if (destination_found == -1) {
325 XBT_DEBUG("It seems that %s is offline...", mailbox);
331 /** @brief Does a pseudo-random lookup for someone in the system
332 * @param node caller node data
334 void random_lookup(node_t node)
336 unsigned int id_to_look = RANDOM_LOOKUP_NODE; //Totally random.
337 /* TODO: Use some pseudorandom generator like RngStream. */
338 XBT_DEBUG("I'm doing a random lookup");
339 find_node(node, id_to_look, 1);
342 /** @brief Send a "FIND_NODE" to a node
343 * @param node sender node data
344 * @param id node we are querying
345 * @param destination node we are trying to find.
347 void send_find_node(node_t node, unsigned int id, unsigned int destination)
349 char mailbox[MAILBOX_NAME_SIZE + 1];
350 /* Gets the mailbox to send to */
351 get_node_mailbox(id, mailbox);
353 msg_task_t task = task_new_find_node(node->id, destination, node->mailbox, MSG_host_get_name(MSG_host_self()));
355 xbt_assert((task != NULL), "Trying to send a NULL task.");
356 MSG_task_dsend(task, mailbox, task_free_v);
357 XBT_VERB("Asking %s for its closest nodes", mailbox);
361 * Sends to the best "kademlia_alpha" nodes in the "node_list" array a "FIND_NODE" request, to ask them for their best nodes
363 unsigned int send_find_node_to_best(node_t node, answer_t node_list)
365 unsigned int i = 0, j = 0;
366 unsigned int destination = node_list->destination_id;
367 node_contact_t node_to_query;
368 while (j < kademlia_alpha && i < node_list->size) {
369 /* We need to have at most "kademlia_alpha" requests each time, according to the protocol */
370 /* Gets the node we want to send the query to */
371 node_to_query = xbt_dynar_get_as(node_list->nodes, i, node_contact_t);
372 if (node_to_query->id != node->id) { /* No need to query ourselves */
373 send_find_node(node, node_to_query->id, destination);
381 /** @brief Handles an incoming received task */
382 void handle_task(node_t node, msg_task_t task)
384 task_data_t data = MSG_task_get_data(task);
385 xbt_assert((data != NULL), "Received NULL data");
386 //Adding/updating the guy to our routing table
387 node_routing_table_update(node, data->sender_id);
388 switch (data->type) {
390 handle_find_node(node, data);
392 case TASK_FIND_NODE_ANSWER:
393 XBT_DEBUG("Received a wrong answer for a FIND_NODE");
396 handle_ping(node, data);
404 /** @brief Handles the answer to an incoming "find_node" task */
405 void handle_find_node(node_t node, task_data_t data)
407 XBT_VERB("Received a FIND_NODE from %s (%s), he's trying to find %08x",
408 data->answer_to, data->issuer_host_name, data->destination_id);
409 //Building the answer to the request
410 answer_t answer = node_find_closest(node, data->destination_id);
411 //Building the task to send
412 msg_task_t task = task_new_find_node_answer(node->id, data->destination_id, answer, node->mailbox,
413 MSG_host_get_name(MSG_host_self()));
415 MSG_task_dsend(task, data->answer_to, task_free_v);
418 /** @brief handles the answer to a ping */
419 void handle_ping(node_t node, task_data_t data)
421 XBT_VERB("Received a PING request from %s (%s)", data->answer_to, data->issuer_host_name);
422 //Building the answer to the request
423 msg_task_t task = task_new_ping_answer(node->id, data->answer_to, MSG_host_get_name(MSG_host_self()));
425 MSG_task_dsend(task, data->answer_to, task_free_v);
428 /** @brief Main function */
429 int main(int argc, char *argv[])
431 MSG_init(&argc, argv);
433 /* Check the arguments */
434 xbt_assert(argc > 2, "Usage: %s platform_file deployment_file\n\tExample: %s msg_platform.xml msg_deployment.xml\n",
437 const char *platform_file = argv[1];
438 const char *deployment_file = argv[2];
440 MSG_create_environment(platform_file);
441 MSG_function_register("node", node);
442 MSG_launch_application(deployment_file);
444 msg_error_t res = MSG_main();
446 XBT_CRITICAL("Messages created: %ld", smx_total_comms);
447 XBT_INFO("Simulated time: %g", MSG_get_clock());
449 return res != MSG_OK;