For the SSSP algorithm Dijkstra's seems to be a nice choice. Currently a
simple breadth-first search is presented here.
- The SSSP algorithm will also be used to determine whether nodes are directly,
- indirectly or not reachable from the source. It will also set the correct
- destination address and port of a node if possible.
+ The SSSP algorithm will also be used to determine whether nodes are
+ reachable from the source. It will also set the correct destination address
+ and port of a node if possible.
*/
#include "system.h"
#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)
*/
for splay_each(node_t, n, mesh->nodes) {
n->status.visited = false;
- n->status.indirect = true;
n->distance = -1;
}
/* Begin with mesh->self */
- mesh->self->status.visited = true;
- mesh->self->status.indirect = false;
+ mesh->self->status.visited = mesh->threadstarted;
mesh->self->nexthop = mesh->self;
mesh->self->prevedge = NULL;
- mesh->self->via = mesh->self;
mesh->self->distance = 0;
list_insert_head(todo_list, mesh->self);
of nodes behind it.
*/
- bool indirect = n->status.indirect || e->options & OPTION_INDIRECT;
-
if(e->to->status.visited
- && (!e->to->status.indirect || indirect)
&& (e->to->distance != n->distance + 1 || e->weight >= e->to->prevedge->weight)) {
continue;
}
e->to->status.visited = true;
- e->to->status.indirect = indirect;
e->to->nexthop = (n->nexthop == mesh->self) ? e->to : n->nexthop;
e->to->prevedge = e;
- e->to->via = indirect ? n->via : e->to;
- e->to->options = e->options;
e->to->distance = n->distance + 1;
if(!e->to->status.reachable || (e->to->address.sa.sa_family == AF_UNSPEC && e->address.sa.sa_family != AF_UNKNOWN)) {
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;
-
- 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);
+ n->status.dirty = true;
+
+ 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? */
timeout_del(&mesh->loop, &n->mtutimeout);
- update_node_status(mesh, n);
+ if(!n->status.blacklisted) {
+ update_node_status(mesh, n);
+ }
if(!n->status.reachable) {
update_node_udp(mesh, n, NULL);
n->status.broadcast = false;
- n->options = 0;
} else if(n->connection) {
- if(n->connection->outgoing) {
+ if(n->connection->status.initiator) {
send_req_key(mesh, n);
}
}
+
+ if(n->utcp) {
+ utcp_offline(n->utcp, !n->status.reachable);
+ }
}
}
+
+ 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);
}
projects / meshlink / blobdiff