+
+ /* Begin with myself */
+
+ myself->status.visited = true;
+ myself->status.indirect = false;
+ myself->nexthop = myself;
+ myself->prevedge = NULL;
+ myself->via = myself;
+ myself->distance = 0;
+ list_insert_head(todo_list, myself);
+
+ /* Loop while todo_list is filled */
+
+ for list_each(node_t, n, todo_list) { /* "n" is the node from which we start */
+ logger(DEBUG_SCARY_THINGS, LOG_DEBUG, " Examining edges from %s", n->name);
+
+ if(n->distance < 0)
+ abort();
+
+ for splay_each(edge_t, e, n->edge_tree) { /* "e" is the edge connected to "from" */
+ if(!e->reverse)
+ continue;
+
+ /* Situation:
+
+ /
+ /
+ ----->(n)---e-->(e->to)
+ \
+ \
+
+ Where e is an edge, (n) and (e->to) are nodes.
+ n->address is set to the e->address of the edge left of n to n.
+ We are currently examining the edge e right of n from n:
+
+ - If edge e provides for better reachability of e->to, update
+ e->to and (re)add it to the todo_list to (re)examine the reachability
+ 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;
+
+ // Only update nexthop if it doesn't increase the path length
+
+ if(!e->to->status.visited || (e->to->distance == n->distance + 1 && e->weight >= e->to->prevedge->weight))
+ e->to->nexthop = (n->nexthop == myself) ? e->to : n->nexthop;
+
+ e->to->status.visited = true;
+ e->to->status.indirect = indirect;
+ 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))
+ update_node_udp(e->to, &e->address);
+
+ list_insert_tail(todo_list, e->to);
+ }
+
+ next = node->next; /* Because the list_insert_tail() above could have added something extra for us! */
+ list_delete_node(todo_list, node);
+ }
+
+ list_free(todo_list);
+}
+
+static void check_reachability(void) {
+ /* Check reachability status. */
+
+ int reachable_count = 0;
+ int became_reachable_count = 0;
+ int became_unreachable_count = 0;
+ for splay_each(node_t, n, node_tree) {
+ if(n->status.visited != n->status.reachable) {
+ n->status.reachable = !n->status.reachable;
+ n->last_state_change = now.tv_sec;
+
+ if(n->status.reachable) {
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "Node %s (%s) became reachable",
+ n->name, n->hostname);
+ if (n != myself)
+ became_reachable_count++;
+ } else {
+ logger(DEBUG_TRAFFIC, LOG_DEBUG, "Node %s (%s) became unreachable",
+ n->name, n->hostname);
+ if (n != myself)
+ became_unreachable_count++;
+ }
+
+ if(experimental && OPTION_VERSION(n->options) >= 2)
+ n->status.sptps = true;
+
+ /* TODO: only clear status.validkey if node is unreachable? */
+
+ n->status.validkey = false;
+ if(n->status.sptps) {
+ sptps_stop(&n->sptps);
+ n->status.waitingforkey = false;
+ }
+ n->last_req_key = 0;
+
+ n->status.udp_confirmed = false;
+ n->maxmtu = MTU;
+ n->maxrecentlen = 0;
+ n->minmtu = 0;
+ n->mtuprobes = 0;
+
+ timeout_del(&n->udp_ping_timeout);
+
+ char *name;
+ char *address;
+ char *port;
+ char *envp[8] = {NULL};
+
+ xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
+ xasprintf(&envp[1], "DEVICE=%s", device ? : "");
+ xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
+ xasprintf(&envp[3], "NODE=%s", n->name);
+ sockaddr2str(&n->address, &address, &port);
+ xasprintf(&envp[4], "REMOTEADDRESS=%s", address);
+ xasprintf(&envp[5], "REMOTEPORT=%s", port);
+ xasprintf(&envp[6], "NAME=%s", myself->name);
+
+ execute_script(n->status.reachable ? "host-up" : "host-down", envp);
+
+ xasprintf(&name, n->status.reachable ? "hosts/%s-up" : "hosts/%s-down", n->name);
+ execute_script(name, envp);
+
+ free(name);
+ free(address);
+ free(port);
+
+ for(int i = 0; i < 7; i++)
+ free(envp[i]);
+
+ subnet_update(n, NULL, n->status.reachable);
+
+ if(!n->status.reachable) {
+ update_node_udp(n, NULL);
+ memset(&n->status, 0, sizeof n->status);
+ n->options = 0;
+ } else if(n->connection) {
+ // Speed up UDP probing by sending our key.
+ if(!n->status.sptps)
+ send_ans_key(n);
+ }
+ }
+
+ if(n->status.reachable && n != myself)
+ reachable_count++;
+ }
+
+ if (device_standby) {
+ if (reachable_count == 0 && became_unreachable_count > 0)
+ device_disable();
+ else if (reachable_count > 0 && reachable_count == became_reachable_count)
+ device_enable();