/* * Ouroboros - Copyright (C) 2016 - 2017 * * Undirected graph structure * * Dimitri Staessens <dimitri.staessens@ugent.be> * Sander Vrijders <sander.vrijders@ugent.be> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., http://www.fsf.org/about/contact/. */ #define _POSIX_C_SOURCE 200112L #define OUROBOROS_PREFIX "graph" #include <ouroboros/logs.h> #include <ouroboros/errno.h> #include <ouroboros/list.h> #include "graph.h" #include "ipcp.h" #include <assert.h> #include <pthread.h> #include <stdlib.h> #include <limits.h> struct edge { struct list_head next; struct vertex * nb; qosspec_t qs; }; struct vertex { struct list_head next; uint64_t addr; struct list_head edges; }; struct graph { size_t nr_vertices; struct list_head vertices; pthread_mutex_t lock; }; static struct edge * find_edge_by_addr(struct vertex * vertex, uint64_t dst_addr) { struct list_head * p = NULL; list_for_each(p, &vertex->edges) { struct edge * e = list_entry(p, struct edge, next); if (e->nb->addr == dst_addr) return e; } return NULL; } static struct vertex * find_vertex_by_addr(struct graph * graph, uint64_t addr) { struct list_head * p = NULL; list_for_each(p, &graph->vertices) { struct vertex * e = list_entry(p, struct vertex, next); if (e->addr == addr) return e; } return NULL; } static struct edge * add_edge(struct vertex * vertex, struct vertex * nb) { struct edge * edge; edge = malloc(sizeof(*edge)); if (edge == NULL) return NULL; list_head_init(&edge->next); edge->nb = nb; list_add(&edge->next, &vertex->edges); return edge; } static void del_edge(struct edge * edge) { list_del(&edge->next); free(edge); } static struct vertex * add_vertex(struct graph * graph, uint64_t addr) { struct vertex * vertex; struct list_head * p; vertex = malloc(sizeof(*vertex)); if (vertex == NULL) return NULL; list_head_init(&vertex->next); list_head_init(&vertex->edges); vertex->addr = addr; list_for_each(p, &graph->vertices) { struct vertex * v = list_entry(p, struct vertex, next); if (v->addr > addr) break; } list_add_tail(&vertex->next, p); graph->nr_vertices++; return vertex; } static void del_vertex(struct graph * graph, struct vertex * vertex) { struct list_head * p = NULL; struct list_head * n = NULL; list_del(&vertex->next); list_for_each_safe(p, n, &vertex->edges) { struct edge * e = list_entry(p, struct edge, next); del_edge(e); } free(vertex); graph->nr_vertices--; } struct graph * graph_create(void) { struct graph * graph; graph = malloc(sizeof(*graph)); if (graph == NULL) return NULL; if (pthread_mutex_init(&graph->lock, NULL)) { free(graph); return NULL; } graph->nr_vertices = 0; list_head_init(&graph->vertices); return graph; } void graph_destroy(struct graph * graph) { struct list_head * p = NULL; struct list_head * n = NULL; assert(graph); pthread_mutex_lock(&graph->lock); list_for_each_safe(p, n, &graph->vertices) { struct vertex * e = list_entry(p, struct vertex, next); del_vertex(graph, e); } pthread_mutex_unlock(&graph->lock); pthread_mutex_destroy(&graph->lock); free(graph); } int graph_update_edge(struct graph * graph, uint64_t s_addr, uint64_t d_addr, qosspec_t qs) { struct vertex * v; struct edge * e; struct vertex * nb; struct edge * nb_e; assert(graph); pthread_mutex_lock(&graph->lock); v = find_vertex_by_addr(graph, s_addr); if (v == NULL) { v = add_vertex(graph, s_addr); if (v == NULL) { pthread_mutex_unlock(&graph->lock); log_err("Failed to add vertex."); return -ENOMEM; } } nb = find_vertex_by_addr(graph, d_addr); if (nb == NULL) { nb = add_vertex(graph, d_addr); if (nb == NULL) { if (list_is_empty(&v->edges)) del_vertex(graph, v); pthread_mutex_unlock(&graph->lock); log_err("Failed to add vertex."); return -ENOMEM; } } e = find_edge_by_addr(v, d_addr); if (e == NULL) { e = add_edge(v, nb); if (e == NULL) { if (list_is_empty(&v->edges)) del_vertex(graph, v); if (list_is_empty(&nb->edges)) del_vertex(graph, nb); pthread_mutex_unlock(&graph->lock); log_err("Failed to add edge."); return -ENOMEM; } } e->qs = qs; nb_e = find_edge_by_addr(nb, s_addr); if (nb_e == NULL) { nb_e = add_edge(nb, v); if (nb_e == NULL) { del_edge(e); if (list_is_empty(&v->edges)) del_vertex(graph, v); if (list_is_empty(&nb->edges)) del_vertex(graph, nb); pthread_mutex_unlock(&graph->lock); log_err("Failed to add edge."); return -ENOMEM; } } nb_e->qs = qs; pthread_mutex_unlock(&graph->lock); return 0; } int graph_del_edge(struct graph * graph, uint64_t s_addr, uint64_t d_addr) { struct vertex * v; struct edge * e; struct vertex * nb; struct edge * nb_e; assert(graph); pthread_mutex_lock(&graph->lock); v = find_vertex_by_addr(graph, s_addr); if (v == NULL) { pthread_mutex_unlock(&graph->lock); log_err("No such vertex."); return -1; } nb = find_vertex_by_addr(graph, d_addr); if (nb == NULL) { pthread_mutex_unlock(&graph->lock); log_err("No such vertex."); return -1; } e = find_edge_by_addr(v, d_addr); if (e == NULL) { pthread_mutex_unlock(&graph->lock); log_err("No such edge."); return -1; } nb_e = find_edge_by_addr(nb, s_addr); if (nb_e == NULL) { pthread_mutex_unlock(&graph->lock); log_err("No such edge."); return -1; } del_edge(e); del_edge(nb_e); /* Removing vertex if it was the last edge */ if (list_is_empty(&v->edges)) del_vertex(graph, v); if (list_is_empty(&nb->edges)) del_vertex(graph, nb); pthread_mutex_unlock(&graph->lock); return 0; } static int get_min_vertex(struct vertex ** vertices, int nr_vertices, int * dist, struct vertex ** v) { int min = INT_MAX; int index = -1; int i; *v = NULL; for (i = 0; i < nr_vertices; i++) { if (vertices[i] == NULL) continue; if (dist[i] < min) { *v = vertices[i]; min = dist[i]; index = i; } } if (index != -1) vertices[index] = NULL; return index; } static int get_vertex_number(struct vertex ** vertices, int nr_vertices, struct vertex * v) { int i; for (i = 0; i < nr_vertices; i++) { if (vertices[i] == v) return i; } return -1; } static int get_vertex_index(struct graph * graph, struct vertex * v) { struct list_head * p = NULL; struct vertex * vertex; int i = 0; list_for_each(p, &graph->vertices) { vertex = list_entry(p, struct vertex, next); if (vertex == v) return i; i++; } return -1; } static struct vertex ** dijkstra(struct graph * graph, uint64_t src) { int dist[graph->nr_vertices]; struct vertex * vertices[graph->nr_vertices]; struct list_head * p = NULL; int i = 0; int j = 0; struct vertex * v = NULL; struct edge * e = NULL; int alt; struct vertex ** prev; prev = malloc(sizeof(*prev) * graph->nr_vertices); if (prev == NULL) return NULL; /* Init the data structures */ list_for_each(p, &graph->vertices) { v = list_entry(p, struct vertex, next); vertices[i] = v; if (v->addr == src) dist[i] = 0; else dist[i] = INT_MAX; prev[i] = NULL; i++; } /* Perform actual Dijkstra */ i = get_min_vertex(vertices, graph->nr_vertices, dist, &v); while (v != NULL) { list_for_each(p, &v->edges) { e = list_entry(p, struct edge, next); j = get_vertex_number(vertices, graph->nr_vertices, e->nb); if (j == -1) continue; /* * NOTE: Current weight is just hop count. * Method could be extended to use a different * weight for a different QoS cube. */ alt = dist[i] + 1; if (alt < dist[j]) { dist[j] = alt; prev[j] = v; } } i = get_min_vertex(vertices, graph->nr_vertices, dist, &v); } return prev; } ssize_t graph_routing_table(struct graph * graph, uint64_t s_addr, struct routing_table *** table) { struct vertex ** prevs; struct list_head * p = NULL; int i = 0; int index = 0; int j = 0; int k = 0; struct vertex * prev; struct vertex * nhop; struct vertex * v; pthread_mutex_lock(&graph->lock); /* We need at least 2 vertices for a table */ if (graph->nr_vertices < 2) { pthread_mutex_unlock(&graph->lock); return -1; } prevs = dijkstra(graph, s_addr); if (prevs == NULL) { pthread_mutex_unlock(&graph->lock); return -1; } *table = malloc(sizeof(**table) * (graph->nr_vertices - 1)); if (*table == NULL) { pthread_mutex_unlock(&graph->lock); free(prevs); return -1; } /* * Now loop through the list of predecessors * to construct the routing table */ list_for_each(p, &graph->vertices) { v = list_entry(p, struct vertex, next); prev = prevs[i]; nhop = v; /* This is the src */ if (prev == NULL) { i++; continue; } index = get_vertex_index(graph, prev); while (prevs[index] != NULL) { nhop = prev; prev = prevs[index]; index = get_vertex_index(graph, prev); } (*table)[j] = malloc(sizeof(***table)); if ((*table)[j] == NULL) { pthread_mutex_unlock(&graph->lock); for (k = 0; k < j; ++k) free((*table)[k]); free(*table); free(prevs); return -1; } (*table)[j]->dst = v->addr; (*table)[j]->nhop = nhop->addr; j++; i++; } pthread_mutex_unlock(&graph->lock); free(prevs); return j; }