Avoid allocating packet buffers unnecessarily.

[meshlink] / src / graph.c

diff --git a/src/graph.c b/src/graph.c
index 60ac3adfc362a50806ac93b3b5e44850813f2ef7..b0e0b77a198a408cd2d88aecb2c4debde09022d3 100644 (file)
--- a/src/graph.c
+++ b/src/graph.c
@@ -56,65 +56,6 @@
 #include "xalloc.h"
 #include "graph.h"
 
-/* Implementation of Kruskal's algorithm.
-   Running time: O(EN)
-   Please note that sorting on weight is already done by add_edge().
-*/
-
-static void mst_kruskal(meshlink_handle_t *mesh) {
-       /* Clear MST status on connections */
-
-       for list_each(connection_t, c, mesh->connections) {
-               c->status.mst = false;
-       }
-
-       logger(mesh, MESHLINK_DEBUG, "Running Kruskal's algorithm:");
-
-       /* Clear visited status on nodes */
-
-       for splay_each(node_t, n, mesh->nodes) {
-               n->status.visited = false;
-       }
-
-       /* Starting point */
-
-       for splay_each(edge_t, e, mesh->edges) {
-               if(e->from->status.reachable) {
-                       e->from->status.visited = true;
-                       break;
-               }
-       }
-
-       /* Add safe edges */
-
-       bool skipped = false;
-
-       for splay_each(edge_t, e, mesh->edges) {
-               if(!e->reverse || (e->from->status.visited == e->to->status.visited)) {
-                       skipped = true;
-                       continue;
-               }
-
-               e->from->status.visited = true;
-               e->to->status.visited = true;
-
-               if(e->connection) {
-                       e->connection->status.mst = true;
-               }
-
-               if(e->reverse->connection) {
-                       e->reverse->connection->status.mst = true;
-               }
-
-               logger(mesh, MESHLINK_DEBUG, " Adding edge %s - %s weight %d", e->from->name, e->to->name, e->weight);
-
-               if(skipped) {
-                       skipped = false;
-                       next = mesh->edges->head;
-               }
-       }
-}
-
 /* Implementation of a simple breadth-first search algorithm.
    Running time: O(E)
 */
@@ -131,7 +72,7 @@ static void sssp_bfs(meshlink_handle_t *mesh) {
 
        /* Begin with mesh->self */
 
-       mesh->self->status.visited = true;
+       mesh->self->status.visited = mesh->threadstarted;
        mesh->self->nexthop = mesh->self;
        mesh->self->prevedge = NULL;
        mesh->self->distance = 0;
@@ -195,15 +136,59 @@ static void sssp_bfs(meshlink_handle_t *mesh) {
 static void check_reachability(meshlink_handle_t *mesh) {
        /* Check reachability status. */
 
+       int reachable = -1; /* Don't count ourself */
+
        for splay_each(node_t, n, mesh->nodes) {
+               if(n->status.visited) {
+                       reachable++;
+               }
+
+               /* Check for nodes that have changed session_id */
+               if(n->status.visited && n->prevedge && n->prevedge->reverse->session_id != n->session_id) {
+                       n->session_id = n->prevedge->reverse->session_id;
+
+                       if(n->utcp) {
+                               utcp_abort_all_connections(n->utcp);
+                       }
+
+                       if(n->status.visited == n->status.reachable) {
+                               /* This session replaces the previous one without changing reachability status.
+                                * We still need to reset the UDP SPTPS state.
+                                */
+                               n->status.validkey = false;
+                               sptps_stop(&n->sptps);
+                               n->status.waitingforkey = false;
+                               n->last_req_key = 0;
+
+                               n->status.udp_confirmed = false;
+                               n->maxmtu = MTU;
+                               n->minmtu = 0;
+                               n->mtuprobes = 0;
+
+                               timeout_del(&mesh->loop, &n->mtutimeout);
+                       }
+               }
+
                if(n->status.visited != n->status.reachable) {
                        n->status.reachable = !n->status.reachable;
-                       n->last_state_change = mesh->loop.now.tv_sec;
+                       n->status.dirty = true;
 
-                       if(n->status.reachable) {
-                               logger(mesh, MESHLINK_DEBUG, "Node %s became reachable", n->name);
-                       } else {
-                               logger(mesh, MESHLINK_DEBUG, "Node %s became unreachable", n->name);
+                       if(!n->status.blacklisted) {
+                               if(n->status.reachable) {
+                                       logger(mesh, MESHLINK_DEBUG, "Node %s became reachable", n->name);
+                                       bool first_time_reachable = !n->last_reachable;
+                                       n->last_reachable = time(NULL);
+
+                                       if(first_time_reachable) {
+                                               if(!node_write_config(mesh, n)) {
+                                                       logger(mesh, MESHLINK_WARNING, "Could not write host config file for node %s!\n", n->name);
+
+                                               }
+                                       }
+                               } else {
+                                       logger(mesh, MESHLINK_DEBUG, "Node %s became unreachable", n->name);
+                                       n->last_unreachable = time(NULL);
+                               }
                        }
 
                        /* TODO: only clear status.validkey if node is unreachable? */
@@ -238,10 +223,23 @@ static void check_reachability(meshlink_handle_t *mesh) {
                        }
                }
        }
+
+       if(mesh->reachable != reachable) {
+               if(!reachable) {
+                       mesh->last_unreachable = mesh->loop.now.tv_sec;
+
+                       if(mesh->threadstarted) {
+                               timeout_set(&mesh->loop, &mesh->periodictimer, &(struct timespec) {
+                                       0, prng(mesh, TIMER_FUDGE)
+                               });
+                       }
+               }
+
+               mesh->reachable = reachable;
+       }
 }
 
 void graph(meshlink_handle_t *mesh) {
        sssp_bfs(mesh);
        check_reachability(mesh);
-       mst_kruskal(mesh);
 }