1 /* Copyright (c) 2010-2018. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
7 #include "routing_table.h"
8 #include "simgrid/msg.h"
10 #include <stdio.h> /* snprintf */
12 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_kademlia_node, "Messages specific for this msg example");
14 /** @brief Initialization of a node
15 * @param node_id the id of the node
16 * @return the node created
18 node_t node_init(unsigned int node_id)
20 node_t node = xbt_new(s_node_t, 1);
23 node->table = routing_table_init(node_id);
24 snprintf(node->mailbox, MAILBOX_NAME_SIZE - 1, "%u", node_id);
25 node->find_node_failed = 0;
26 node->find_node_success = 0;
28 node->task_received = NULL;
29 node->receive_comm = NULL;
34 /* @brief Node destructor */
35 void node_free(node_t node)
37 routing_table_free(node->table);
41 /** @brief Updates/Puts the node id unsigned into our routing table
42 * @param node Our node data
43 * @param id The id of the node we need to add unsigned into our routing table
45 void node_routing_table_update(node_t node, unsigned int id)
47 routing_table_t table = node->table;
48 //retrieval of the bucket in which the should be
49 bucket_t bucket = routing_table_find_bucket(table, id);
51 //check if the id is already in the bucket.
52 unsigned int id_pos = bucket_find_id(bucket, id);
55 /* We check if the bucket is full or not. If it is, we evict old offline elements */
56 if (xbt_dynar_length(bucket->nodes) < bucket_size) {
57 //TODO: this is not really very efficient. Maybe we should use something else than dynars ?
58 xbt_dynar_unshift(bucket->nodes, &id);
59 XBT_VERB("I'm adding to my routing table %08x", id);
61 /* TODO: we need to evict the old elements: that's why this function is in "node" instead of "routing table".
62 * This is not implemented yet. */
65 //We push to the front of the dynar the element.
66 unsigned int element = xbt_dynar_get_as(bucket->nodes, id_pos, unsigned int);
67 xbt_dynar_remove_at(bucket->nodes, id_pos, NULL);
68 xbt_dynar_unshift(bucket->nodes, &element);
69 XBT_VERB("I'm updating %08x", element);
73 /** @brief Finds the closest nodes to the node given.
74 * @param node : our node
75 * @param destination_id : the id of the guy we are trying to find
77 answer_t node_find_closest(node_t node, unsigned int destination_id)
80 answer_t answer = answer_init(destination_id);
81 /* We find the corresponding bucket for the id */
82 bucket_t bucket = routing_table_find_bucket(node->table, destination_id);
83 int bucket_id = bucket->id;
84 xbt_assert((bucket_id <= identifier_size), "Bucket found has a wrong identifier");
85 /* So, we copy the contents of the bucket unsigned into our result dynar */
86 answer_add_bucket(bucket, answer);
88 /* However, if we don't have enough elements in our bucket, we NEED to include at least "bucket_size" elements
89 * (if, of course, we know at least "bucket_size" elements. So we're going to look unsigned into the other buckets.
91 for (i = 1; answer->size < bucket_size && ((bucket_id - i > 0) || (bucket_id + i < identifier_size)); i++) {
92 /* We check the previous buckets */
93 if (bucket_id - i >= 0) {
94 bucket_t bucket_p = &node->table->buckets[bucket_id - i];
95 answer_add_bucket(bucket_p, answer);
97 /* We check the next buckets */
98 if (bucket_id + i <= identifier_size) {
99 bucket_t bucket_n = &node->table->buckets[bucket_id + i];
100 answer_add_bucket(bucket_n, answer);
103 /* We sort the array by XOR distance */
105 /* We trim the array to have only bucket_size or less elements */
111 /**@brief Returns an identifier which is in a specific bucket of a routing table
112 * @param id id of the routing table owner
113 * @param prefix id of the bucket where we want that identifier to be
115 unsigned int get_id_in_prefix(unsigned int id, unsigned int prefix)
120 return (1U << ((unsigned int)(prefix - 1))) ^ id;
124 /** @brief Returns the prefix of an identifier.
125 * The prefix is the id of the bucket in which the remote identifier xor our identifier should be stored.
126 * @param id : big unsigned int id to test
127 * @param nb_bits : key size
129 unsigned int get_node_prefix(unsigned int id, unsigned int nb_bits)
131 unsigned int size = sizeof(unsigned int) * 8;
132 for (unsigned int j = 0; j < size; j++) {
133 if (((id >> (size - 1 - j)) & 0x1) != 0) {
134 return nb_bits - (j);
140 /** @brief Gets the mailbox name of a host given its identifier */
141 void get_node_mailbox(unsigned int id, char *mailbox)
143 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%u", id);
146 /** Constructor, build a new contact information. */
147 node_contact_t node_contact_new(unsigned int id, unsigned int distance)
149 node_contact_t contact = xbt_new(s_node_contact_t, 1);
152 contact->distance = distance;
157 /** Builds a contact information from a contact information */
158 node_contact_t node_contact_copy(node_contact_t node_contact)
160 node_contact_t contact = xbt_new(s_node_contact_t, 1);
162 contact->id = node_contact->id;
163 contact->distance = node_contact->distance;
169 void node_contact_free(node_contact_t contact)