/*
graph.c -- graph algorithms
- Copyright (C) 2001 Guus Sliepen <guus@sliepen.warande.net>,
- 2001 Ivo Timmermans <itimmermans@bigfoot.com>
+ Copyright (C) 2001-2013 Guus Sliepen <guus@tinc-vpn.org>,
+ 2001-2005 Ivo Timmermans
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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., 675 Mass Ave, Cambridge, MA 02139, USA.
-
- $Id: graph.c,v 1.1.2.5 2001/10/31 12:50:24 guus Exp $
+ 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.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/* We need to generate two trees from the graph:
For the SSSP algorithm Dijkstra's seems to be a nice choice. Currently a
simple breadth-first search is presented here.
-*/
-#include <syslog.h>
-#include "config.h"
-#include <string.h>
+ 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.
+*/
-#include <avl_tree.h>
+#include "system.h"
-#include "node.h"
-#include "edge.h"
#include "connection.h"
-
-#include "system.h"
+#include "device.h"
+#include "edge.h"
+#include "graph.h"
+#include "list.h"
+#include "logger.h"
+#include "names.h"
+#include "netutl.h"
+#include "node.h"
+#include "protocol.h"
+#include "script.h"
+#include "subnet.h"
+#include "utils.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().
*/
-void mst_kruskal(void)
-{
- avl_node_t *node, *next;
- edge_t *e;
- node_t *n;
- connection_t *c;
- int nodes = 0;
- int safe_edges = 0;
- int skipped;
-
- /* Clear visited status on nodes */
-
- for(node = node_tree->head; node; node = node->next)
- {
- n = (node_t *)node->data;
- n->status.visited = 0;
- nodes++;
- }
-
- /* Starting point */
-
- ((edge_t *)edge_weight_tree->head->data)->from->status.visited = 1;
-
- /* Clear MST status on connections */
-
- for(node = connection_tree->head; node; node = node->next)
- {
- c = (connection_t *)node->data;
- c->status.mst = 0;
- }
-
- /* Add safe edges */
-
- for(skipped = 0, node = edge_weight_tree->head; node; node = next)
- {
- next = node->next;
- e = (edge_t *)node->data;
-
- if(e->from->status.visited == e->to->status.visited)
- {
- skipped = 1;
- continue;
- }
-
- e->from->status.visited = 1;
- e->to->status.visited = 1;
- if(e->connection)
- e->connection->status.mst = 1;
-
- safe_edges++;
-
- if(skipped)
- {
- next = edge_weight_tree->head;
- continue;
- }
- }
+static void mst_kruskal(void) {
+ /* Clear MST status on connections */
+
+ for list_each(connection_t, c, connection_list)
+ c->status.mst = false;
+
+ logger(DEBUG_SCARY_THINGS, LOG_DEBUG, "Running Kruskal's algorithm:");
+
+ /* Clear visited status on nodes */
+
+ for splay_each(node_t, n, node_tree)
+ n->status.visited = false;
+
+ /* Starting point */
+
+ for splay_each(edge_t, e, edge_weight_tree) {
+ if(e->from->status.reachable) {
+ e->from->status.visited = true;
+ break;
+ }
+ }
+
+ /* Add safe edges */
+
+ bool skipped = false;
+
+ for splay_each(edge_t, e, edge_weight_tree) {
+ 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(DEBUG_SCARY_THINGS, LOG_DEBUG, " Adding edge %s - %s weight %d", e->from->name, e->to->name, e->weight);
+
+ if(skipped) {
+ skipped = false;
+ next = edge_weight_tree->head;
+ }
+ }
}
/* Implementation of a simple breadth-first search algorithm.
Running time: O(E)
*/
-void sssp_bfs(int prune)
-{
- avl_node_t *node, *from, *next, *to;
- edge_t *e;
- node_t *n, *check;
- avl_tree_t *todo_tree;
-
- todo_tree = avl_alloc_tree(NULL, NULL);
-
- /* Clear visited status on nodes */
-
- for(node = node_tree->head; node; node = node->next)
- {
- n = (node_t *)node->data;
- n->status.visited = 0;
- }
-
- /* Begin with myself */
-
- myself->status.visited = 1;
- myself->nexthop = myself;
- myself->via = myself;
- node = avl_alloc_node();
- node->data = myself;
- avl_insert_top(todo_tree, node);
-
- /* Loop while todo_tree is filled */
-
- while(todo_tree->head)
- {
- for(from = todo_tree->head; from; from = next)
- {
- next = from->next;
- n = (node_t *)from->data;
-
- for(to = n->edge_tree->head; to; to = to->next)
- {
- e = (edge_t *)to->data;
-
- if(e->from == n)
- check = e->to;
- else
- check = e->from;
-
- if(!check->status.visited)
- {
- check->status.visited = 1;
- check->nexthop = (n->nexthop == myself) ? check : n->nexthop;
- check->via = (e->options & OPTION_INDIRECT || n->via != n) ? n->via : check;
- node = avl_alloc_node();
- node->data = check;
- avl_insert_before(todo_tree, from, node);
- }
- }
-
- avl_delete_node(todo_tree, from);
- }
- }
-
- avl_free_tree(todo_tree);
-
- /* Nodes we haven't visited are unreachable, prune them. */
-
- if(prune)
- for(node = node_tree->head; node; node = next)
- {
- next = node->next;
- n = (node_t *)node->data;
-
- if(n->status.visited == 0)
- node_del(n);
- }
+static void sssp_bfs(void) {
+ list_t *todo_list = list_alloc(NULL);
+
+ /* Clear visited status on nodes */
+
+ for splay_each(node_t, n, node_tree) {
+ n->status.visited = false;
+ n->status.indirect = true;
+ n->distance = -1;
+ }
+
+ /* 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 || e->to == myself)
+ 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();
+ }
+}
+
+void graph(void) {
+ subnet_cache_flush();
+ sssp_bfs();
+ check_reachability();
+ mst_kruskal();
}