ipcpd: Restructure policy code

The policies were all in a single folder pol/, and have been moved to
a folder per component/mechanism to keep things a bit more orderly.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 849 insertions, 0 deletions

diff --git a/src/ipcpd/unicast/routing/graph.c b/src/ipcpd/unicast/routing/graph.c
new file mode 100644
index 00000000..6ea5c507
--- /dev/null
+++ b/src/ipcpd/unicast/routing/graph.c
@@ -0,0 +1,849 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2021
+ *
+ * Undirected graph structure
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *    Nick Aerts        <nick.aerts@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/.
+ */
+
+#if defined(__linux__) || defined(__CYGWIN__)
+#define _DEFAULT_SOURCE
+#else
+#define _POSIX_C_SOURCE 200112L
+#endif
+
+#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>
+#include <string.h>
+
+struct vertex {
+        struct list_head next;
+        uint64_t         addr;
+        struct list_head edges;
+        int              index;
+};
+
+struct edge {
+        struct list_head next;
+        struct vertex *  nb;
+        qosspec_t        qs;
+        int              announced;
+};
+
+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;
+
+        assert(vertex);
+
+        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;
+
+        assert(graph);
+
+        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;
+
+        assert(vertex);
+        assert(nb);
+
+        edge = malloc(sizeof(*edge));
+        if (edge == NULL)
+                return NULL;
+
+        edge->nb = nb;
+        edge->announced = 0;
+
+        list_add(&edge->next, &vertex->edges);
+
+        return edge;
+}
+
+static void del_edge(struct edge * edge)
+{
+        assert(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;
+        int                i = 0;
+
+        assert(graph);
+
+        vertex = malloc(sizeof(*vertex));
+        if (vertex == NULL)
+                return NULL;
+
+        list_head_init(&vertex->edges);
+        vertex->addr = addr;
+
+        /* Keep them ordered on address. */
+        list_for_each(p, &graph->vertices) {
+                struct vertex * v = list_entry(p, struct vertex, next);
+                if (v->addr > addr)
+                        break;
+                i++;
+        }
+
+        vertex->index = i;
+
+        list_add_tail(&vertex->next, p);
+
+        /* Increase the index of the vertices to the right. */
+        list_for_each(p, &graph->vertices) {
+                struct vertex * v = list_entry(p, struct vertex, next);
+                if (v->addr > addr)
+                        v->index++;
+        }
+
+        graph->nr_vertices++;
+
+        return vertex;
+}
+
+static void del_vertex(struct graph *  graph,
+                       struct vertex * vertex)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        assert(graph);
+        assert(vertex);
+
+        list_del(&vertex->next);
+
+        /* Decrease the index of the vertices to the right. */
+        list_for_each(p, &graph->vertices) {
+                struct vertex * v = list_entry(p, struct vertex, next);
+                if (v->addr > vertex->addr)
+                        v->index--;
+        }
+
+        list_for_each_safe(p, h, &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->announced++;
+        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) {
+                        if (--e->announced == 0)
+                                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->announced++;
+        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 source vertex.");
+                return -1;
+        }
+
+        nb = find_vertex_by_addr(graph, d_addr);
+        if (nb == NULL) {
+                pthread_mutex_unlock(&graph->lock);
+                log_err("No such destination vertex.");
+                return -1;
+        }
+
+        e = find_edge_by_addr(v, d_addr);
+        if (e == NULL) {
+                pthread_mutex_unlock(&graph->lock);
+                log_err("No such source 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 destination edge.");
+                return -1;
+        }
+
+        if (--e->announced == 0)
+                del_edge(e);
+        if (--nb_e->announced == 0)
+                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 graph *   graph,
+                          int *            dist,
+                          bool *           used,
+                          struct vertex ** v)
+{
+        int                min = INT_MAX;
+        int                index = -1;
+        int                i = 0;
+        struct list_head * p;
+
+        assert(v);
+        assert(graph);
+        assert(dist);
+        assert(used);
+
+        *v = NULL;
+
+        list_for_each(p, &graph->vertices) {
+                if (!used[i] && dist[i] < min) {
+                        min = dist[i];
+                        index = i;
+                        *v = list_entry(p, struct vertex, next);
+                }
+
+                i++;
+        }
+
+        if (index != -1)
+                used[index] = true;
+
+        return index;
+}
+
+static int dijkstra(struct graph *    graph,
+                    uint64_t          src,
+                    struct vertex *** nhops,
+                    int **            dist)
+{
+        bool *             used;
+        struct list_head * p = NULL;
+        int                i = 0;
+        struct vertex *    v = NULL;
+        struct edge *      e = NULL;
+        int                alt;
+
+        assert(graph);
+        assert(nhops);
+        assert(dist);
+
+        *nhops = malloc(sizeof(**nhops) * graph->nr_vertices);
+        if (*nhops == NULL)
+                goto fail_pnhops;
+
+        *dist = malloc(sizeof(**dist) * graph->nr_vertices);
+        if (*dist == NULL)
+                goto fail_pdist;
+
+        used = malloc(sizeof(*used) * graph->nr_vertices);
+        if (used == NULL)
+                goto fail_used;
+
+        /* Init the data structures */
+        memset(used, 0, sizeof(*used) * graph->nr_vertices);
+        memset(*nhops, 0, sizeof(**nhops) * graph->nr_vertices);
+        memset(*dist, 0, sizeof(**dist) * graph->nr_vertices);
+
+        list_for_each(p, &graph->vertices) {
+                v = list_entry(p, struct vertex, next);
+                (*dist)[i++]  = (v->addr == src) ? 0 : INT_MAX;
+        }
+
+        /* Perform actual Dijkstra */
+        i = get_min_vertex(graph, *dist, used, &v);
+        while (v != NULL) {
+                list_for_each(p, &v->edges) {
+                        e = list_entry(p, struct edge, next);
+
+                        /* Only include it if both sides announced it. */
+                        if (e->announced != 2)
+                                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)[e->nb->index]) {
+                                (*dist)[e->nb->index] = alt;
+                                if (v->addr == src)
+                                        (*nhops)[e->nb->index] = e->nb;
+                                else
+                                        (*nhops)[e->nb->index] = (*nhops)[i];
+                        }
+                }
+                i = get_min_vertex(graph, *dist, used, &v);
+        }
+
+        free(used);
+
+        return 0;
+
+ fail_used:
+        free(*dist);
+ fail_pdist:
+        free(*nhops);
+ fail_pnhops:
+        return -1;
+
+}
+
+static void free_routing_table(struct list_head * table)
+{
+        struct list_head * h;
+        struct list_head * p;
+        struct list_head * q;
+        struct list_head * i;
+
+        assert(table);
+
+        list_for_each_safe(p, h, table) {
+                struct routing_table * t =
+                        list_entry(p, struct routing_table, next);
+                list_for_each_safe(q, i, &t->nhops) {
+                        struct nhop * n =
+                                list_entry(q, struct nhop, next);
+                        list_del(&n->next);
+                        free(n);
+                }
+                list_del(&t->next);
+                free(t);
+        }
+}
+
+void graph_free_routing_table(struct graph *     graph,
+                              struct list_head * table)
+{
+        assert(table);
+
+        pthread_mutex_lock(&graph->lock);
+
+        free_routing_table(table);
+
+        pthread_mutex_unlock(&graph->lock);
+}
+
+static int graph_routing_table_simple(struct graph *     graph,
+                                      uint64_t           s_addr,
+                                      struct list_head * table,
+                                      int **             dist)
+{
+        struct vertex **       nhops;
+        struct list_head *     p;
+        int                    i = 0;
+        struct vertex *        v;
+        struct routing_table * t;
+        struct nhop *          n;
+
+        assert(graph);
+        assert(table);
+        assert(dist);
+
+        /* We need at least 2 vertices for a table */
+        if (graph->nr_vertices < 2)
+                goto fail_vertices;
+
+        if (dijkstra(graph, s_addr, &nhops, dist))
+                goto fail_vertices;
+
+        list_head_init(table);
+
+        /* Now construct the routing table from the nhops. */
+        list_for_each(p, &graph->vertices) {
+                v = list_entry(p, struct vertex, next);
+
+                /* This is the src */
+                if (nhops[i] == NULL) {
+                        i++;
+                        continue;
+                }
+
+                t = malloc(sizeof(*t));
+                if (t == NULL)
+                        goto fail_t;
+
+                list_head_init(&t->nhops);
+
+                n = malloc(sizeof(*n));
+                if (n == NULL)
+                        goto fail_n;
+
+                t->dst = v->addr;
+                n->nhop = nhops[i]->addr;
+
+                list_add(&n->next, &t->nhops);
+                list_add(&t->next, table);
+
+                i++;
+        }
+
+        free(nhops);
+
+        return 0;
+
+ fail_n:
+        free(t);
+ fail_t:
+        free_routing_table(table);
+        free(nhops);
+        free(*dist);
+ fail_vertices:
+        *dist = NULL;
+        return -1;
+}
+
+static int add_lfa_to_table(struct list_head * table,
+                            uint64_t           addr,
+                            uint64_t           lfa)
+{
+        struct list_head * p;
+        struct nhop *      n;
+
+        assert(table);
+
+        n = malloc(sizeof(*n));
+        if (n == NULL)
+                return -1;
+
+        n->nhop = lfa;
+
+        list_for_each(p, table) {
+                struct routing_table * t =
+                        list_entry(p, struct routing_table, next);
+                if (t->dst == addr) {
+                        list_add_tail(&n->next, &t->nhops);
+                        return 0;
+                }
+        }
+
+        free(n);
+
+        return -1;
+}
+
+static int graph_routing_table_lfa(struct graph *     graph,
+                                   uint64_t           s_addr,
+                                   struct list_head * table,
+                                   int **             dist)
+{
+        int *              n_dist[PROG_MAX_FLOWS];
+        uint64_t           addrs[PROG_MAX_FLOWS];
+        int                n_index[PROG_MAX_FLOWS];
+        struct list_head * p;
+        struct list_head * q;
+        struct vertex *    v;
+        struct edge *      e;
+        struct vertex **   nhops;
+        int                i = 0;
+        int                j;
+        int                k;
+
+        if (graph_routing_table_simple(graph, s_addr, table, dist))
+                goto fail_table;
+
+        for (j = 0; j < PROG_MAX_FLOWS; j++) {
+                n_dist[j] = NULL;
+                n_index[j] = -1;
+                addrs[j] = -1;
+        }
+
+        list_for_each(p, &graph->vertices) {
+                v = list_entry(p, struct vertex, next);
+
+                if (v->addr != s_addr)
+                        continue;
+
+                /*
+                 * Get the distances for every neighbor
+                 * of the source.
+                 */
+                list_for_each(q, &v->edges) {
+                        e = list_entry(q, struct edge, next);
+
+                        addrs[i] = e->nb->addr;
+                        n_index[i] = e->nb->index;
+                        if (dijkstra(graph, e->nb->addr,
+                                     &nhops, &(n_dist[i++])))
+                                goto fail_dijkstra;
+
+                        free(nhops);
+                }
+
+                break;
+        }
+
+        /* Loop though all nodes to see if we have a LFA for them. */
+        list_for_each(p, &graph->vertices) {
+                v = list_entry(p, struct vertex, next);
+
+                if (v->addr == s_addr)
+                        continue;
+
+                /*
+                 * Check for every neighbor if
+                 * dist(neighbor, destination) <
+                 * dist(neighbor, source) + dist(source, destination).
+                 */
+                for (j = 0; j < i; j++) {
+                        /* Exclude ourselves. */
+                        if (addrs[j] == v->addr)
+                                continue;
+
+                        if (n_dist[j][v->index] <
+                            (*dist)[n_index[j]] + (*dist)[v->index])
+                                if (add_lfa_to_table(table, v->addr,
+                                                     addrs[j]))
+                                        goto fail_add_lfa;
+                }
+        }
+
+        for (j = 0; j < i; j++)
+                free(n_dist[j]);
+
+        return 0;
+
+ fail_add_lfa:
+        for (k = j; k < i; k++)
+                free(n_dist[k]);
+ fail_dijkstra:
+        free_routing_table(table);
+ fail_table:
+        return -1;
+}
+
+static int graph_routing_table_ecmp(struct graph *     graph,
+                                    uint64_t           s_addr,
+                                    struct list_head * table,
+                                    int **             dist)
+{
+        struct vertex **       nhops;
+        struct list_head *     p;
+        struct list_head *     h;
+        size_t                 i;
+        struct vertex *        v;
+        struct vertex *        src_v;
+        struct edge *          e;
+        struct routing_table * t;
+        struct nhop *          n;
+        struct list_head *     forwarding;
+
+        assert(graph);
+        assert(dist);
+
+        if (graph-> nr_vertices < 2)
+                goto fail_vertices;
+
+        forwarding = malloc(sizeof(*forwarding) * graph->nr_vertices);
+        if (forwarding == NULL)
+                goto fail_vertices;
+
+        for (i = 0; i < graph->nr_vertices; ++i)
+                list_head_init(&forwarding[i]);
+
+        if (dijkstra(graph, s_addr, &nhops, dist))
+                goto fail_dijkstra;
+
+        free(nhops);
+
+        src_v = find_vertex_by_addr(graph, s_addr);
+        if (src_v == NULL)
+                goto fail_src_v;
+
+        list_for_each(p, &src_v->edges) {
+                int * tmp_dist;
+
+                e = list_entry(p, struct edge, next);
+                if (dijkstra(graph, e->nb->addr, &nhops, &tmp_dist))
+                        goto fail_src_v;
+
+                free(nhops);
+
+                list_for_each(h, &graph->vertices) {
+                        v = list_entry(h, struct vertex, next);
+                        if (tmp_dist[v->index] + 1 == (*dist)[v->index]) {
+                                n = malloc(sizeof(*n));
+                                if (n == NULL) {
+                                        free(tmp_dist);
+                                        goto fail_src_v;
+                                }
+                                n->nhop = e->nb->addr;
+                                list_add_tail(&n->next, &forwarding[v->index]);
+                        }
+                }
+
+                free(tmp_dist);
+        }
+
+        list_head_init(table);
+        i = 0;
+        list_for_each(p, &graph->vertices) {
+                v = list_entry(p, struct vertex, next);
+                if (v->addr == s_addr) {
+                        ++i;
+                        continue;
+                }
+
+                t = malloc(sizeof(*t));
+                if (t == NULL)
+                        goto fail_t;
+
+                t->dst = v->addr;
+
+                list_head_init(&t->nhops);
+                if (&forwarding[i] != forwarding[i].nxt) {
+                        t->nhops.nxt = forwarding[i].nxt;
+                        t->nhops.prv = forwarding[i].prv;
+                        forwarding[i].prv->nxt = &t->nhops;
+                        forwarding[i].nxt->prv = &t->nhops;
+                }
+
+                list_add(&t->next, table);
+                ++i;
+        }
+
+        free(*dist);
+        *dist = NULL;
+        free(forwarding);
+
+        return 0;
+
+ fail_t:
+        free_routing_table(table);
+ fail_src_v:
+        free(*dist);
+ fail_dijkstra:
+        free(forwarding);
+ fail_vertices:
+        *dist = NULL;
+        return -1;
+}
+
+int graph_routing_table(struct graph *     graph,
+                        enum routing_algo  algo,
+                        uint64_t           s_addr,
+                        struct list_head * table)
+{
+        int * s_dist;
+
+        assert(graph);
+        assert(table);
+
+        pthread_mutex_lock(&graph->lock);
+
+        switch (algo) {
+        case ROUTING_SIMPLE:
+                /* LFA uses the s_dist this returns. */
+                if (graph_routing_table_simple(graph, s_addr, table, &s_dist))
+                        goto fail_table;
+                break;
+        case ROUTING_LFA:
+                if (graph_routing_table_lfa(graph, s_addr, table, &s_dist))
+                        goto fail_table;
+                break;
+
+        case ROUTING_ECMP:
+                if (graph_routing_table_ecmp(graph, s_addr, table, &s_dist))
+                        goto fail_table;
+                break;
+        default:
+                log_err("Unsupported algorithm.");
+                goto fail_table;
+        }
+
+        pthread_mutex_unlock(&graph->lock);
+
+        free(s_dist);
+
+        return 0;
+
+ fail_table:
+        pthread_mutex_unlock(&graph->lock);
+        return -1;
+}