ipcpd: Simplify routing algorithm selection

Previously there was a separate function per routing algorithm
selection, when in fact the algorithms all take as input a graph and
output a routing table, making it possible to place them in a single
function.

Signed-off-by: Sander Vrijders <sander.vrijders@ugent.be>
Signed-off-by: Dimitri Staessens <dimitri.staessens@ugent.be>

3 files changed, 85 insertions, 89 deletions

diff --git a/src/ipcpd/normal/pol/graph.c b/src/ipcpd/normal/pol/graph.c
index f3c053ab..544f0403 100644
--- a/src/ipcpd/normal/pol/graph.c
+++ b/src/ipcpd/normal/pol/graph.c
@@ -547,27 +547,6 @@ static int graph_routing_table_simple(struct graph *     graph,
         return -1;
 }
 
-int graph_routing_table(struct graph *     graph,
-                        uint64_t           s_addr,
-                        struct list_head * table)
-{
-        int   ret = 0;
-        int * dist;
-
-        assert(graph);
-        assert(table);
-
-        pthread_mutex_lock(&graph->lock);
-
-        ret = graph_routing_table_simple(graph, s_addr, table, &dist);
-
-        free(dist);
-
-        pthread_mutex_unlock(&graph->lock);
-
-        return ret;
-}
-
 static int add_lfa_to_table(struct list_head * table,
                             uint64_t           addr,
                             uint64_t           lfa)
@@ -595,9 +574,10 @@ static int add_lfa_to_table(struct list_head * table,
         return -1;
 }
 
-int graph_routing_table_lfa(struct graph *     graph,
-                            uint64_t           s_addr,
-                            struct list_head * table)
+int graph_routing_table(struct graph *     graph,
+                        enum routing_algo  algo,
+                        uint64_t           s_addr,
+                        struct list_head * table)
 {
         int *              s_dist;
         int *              n_dist[PROG_MAX_FLOWS];
@@ -617,66 +597,82 @@ int graph_routing_table_lfa(struct graph *     graph,
 
         pthread_mutex_lock(&graph->lock);
 
-        for (j = 0; j < PROG_MAX_FLOWS; j++) {
-                n_dist[j] = NULL;
-                n_index[j] = -1;
-                addrs[j] = -1;
-        }
-
         /* Get the normal next hops routing table. */
         if (graph_routing_table_simple(graph, s_addr, table, &s_dist))
                 goto fail_table_simple;
 
-        list_for_each(p, &graph->vertices) {
-                v = list_entry(p, struct vertex, next);
+        /* Possibly augment the routing table. */
+        switch (algo) {
+        case ROUTING_SIMPLE:
+                break;
+        case ROUTING_LFA:
+                for (j = 0; j < PROG_MAX_FLOWS; j++) {
+                        n_dist[j] = NULL;
+                        n_index[j] = -1;
+                        addrs[j] = -1;
+                }
 
-                if (v->addr != s_addr)
-                        continue;
+                list_for_each(p, &graph->vertices) {
+                        v = list_entry(p, struct vertex, next);
 
-                /* Get the distances for every neighbor of the source. */
-                list_for_each(q, &v->edges) {
-                        e = list_entry(q, struct edge, next);
+                        if (v->addr != s_addr)
+                                continue;
 
-                        addrs[i] = e->nb->addr;
-                        n_index[i] = e->nb->index;
-                        if (dijkstra(graph, e->nb->addr,
-                                     &nhops, &(n_dist[i++])))
-                                goto fail_dijkstra;
+                        /*
+                         * Get the distances for every neighbor
+                         * of the source.
+                         */
+                        list_for_each(q, &v->edges) {
+                                e = list_entry(q, struct edge, next);
 
-                        free(nhops);
-                }
+                                addrs[i] = e->nb->addr;
+                                n_index[i] = e->nb->index;
+                                if (dijkstra(graph, e->nb->addr,
+                                             &nhops, &(n_dist[i++])))
+                                        goto fail_dijkstra;
 
-                break;
-        }
+                                free(nhops);
+                        }
 
-        /* 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);
+                        break;
+                }
 
-                if (v->addr == s_addr)
-                        continue;
+                /* 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);
 
-                /*
-                 * 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)
+                        if (v->addr == s_addr)
                                 continue;
 
-                        if (n_dist[j][v->index] <
-                            s_dist[n_index[j]] + s_dist[v->index])
-                                if (add_lfa_to_table(table, v->addr, addrs[j]))
-                                        goto fail_add_lfa;
+                        /*
+                         * 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] <
+                                    s_dist[n_index[j]] + s_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]);
+
+                break;
+        default:
+                log_err("Unsupported algorithm.");
+                goto fail_algo;
         }
 
         pthread_mutex_unlock(&graph->lock);
 
-        for (j = 0; j < i; j++)
-                free(n_dist[j]);
-
         free(s_dist);
 
         return 0;
@@ -686,6 +682,7 @@ int graph_routing_table_lfa(struct graph *     graph,
                 free(n_dist[k]);
  fail_dijkstra:
         free_routing_table(table);
+ fail_algo:
         free(s_dist);
  fail_table_simple:
         pthread_mutex_unlock(&graph->lock);
diff --git a/src/ipcpd/normal/pol/graph.h b/src/ipcpd/normal/pol/graph.h
index 13657fd0..7cd14ad6 100644
--- a/src/ipcpd/normal/pol/graph.h
+++ b/src/ipcpd/normal/pol/graph.h
@@ -28,6 +28,11 @@
 
 #include <inttypes.h>
 
+enum routing_algo {
+         ROUTING_SIMPLE = 0,
+         ROUTING_LFA
+};
+
 struct nhop {
         struct list_head next;
         uint64_t         nhop;
@@ -53,13 +58,10 @@ int            graph_del_edge(struct graph * graph,
                               uint64_t       d_addr);
 
 int            graph_routing_table(struct graph *     graph,
+                                   enum routing_algo  algo,
                                    uint64_t           s_addr,
                                    struct list_head * table);
 
-int            graph_routing_table_lfa(struct graph *     graph,
-                                       uint64_t           s_addr,
-                                       struct list_head * table);
-
 void           graph_free_routing_table(struct graph *     graph,
                                         struct list_head * table);
 
diff --git a/src/ipcpd/normal/pol/link_state.c b/src/ipcpd/normal/pol/link_state.c
index 1c418ffc..59bae616 100644
--- a/src/ipcpd/normal/pol/link_state.c
+++ b/src/ipcpd/normal/pol/link_state.c
@@ -101,30 +101,26 @@ struct nb {
         enum nb_type     type;
 };
 
-typedef int (* rtable_fn_t)(struct graph *     graph,
-                            uint64_t           s_addr,
-                            struct list_head * table);
-
 struct {
-        struct list_head nbs;
-        size_t           nbs_len;
-        fset_t *         mgmt_set;
+        struct list_head  nbs;
+        size_t            nbs_len;
+        fset_t *          mgmt_set;
 
-        struct list_head db;
-        size_t           db_len;
+        struct list_head  db;
+        size_t            db_len;
 
-        pthread_rwlock_t db_lock;
+        pthread_rwlock_t  db_lock;
 
-        struct graph *   graph;
+        struct graph *    graph;
 
-        pthread_t        lsupdate;
-        pthread_t        lsreader;
-        pthread_t        listener;
+        pthread_t         lsupdate;
+        pthread_t         lsreader;
+        pthread_t         listener;
 
-        struct list_head routing_instances;
-        pthread_mutex_t  routing_i_lock;
+        struct list_head  routing_instances;
+        pthread_mutex_t   routing_i_lock;
 
-        rtable_fn_t      rtable;
+        enum routing_algo routing_algo;
 } ls;
 
 struct pol_routing_ops link_state_ops = {
@@ -500,7 +496,8 @@ static void calculate_pff(struct routing_i * instance)
         struct list_head * q;
         int                fds[PROG_MAX_FLOWS];
 
-        if (ls.rtable(ls.graph, ipcpi.dt_addr, &table))
+        if (graph_routing_table(ls.graph, ls.routing_algo,
+                                ipcpi.dt_addr, &table))
                 return;
 
         pff_lock(instance->pff);
@@ -902,11 +899,11 @@ int link_state_init(enum pol_routing pr)
         switch (pr) {
         case ROUTING_LINK_STATE:
                 log_dbg("Using link state routing policy.");
-                ls.rtable = graph_routing_table;
+                ls.routing_algo = ROUTING_SIMPLE;
                 break;
         case ROUTING_LINK_STATE_LFA:
                 log_dbg("Using Loop-Free Alternates policy.");
-                ls.rtable = graph_routing_table_lfa;
+                ls.routing_algo = ROUTING_LFA;
                 break;
         default:
                 goto fail_graph;