/*
graph.c -- graph algorithms
- Copyright (C) 2001-2002 Guus Sliepen <guus@sliepen.warande.net>,
- 2001-2002 Ivo Timmermans <itimmermans@bigfoot.com>
+ Copyright (C) 2001-2012 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 1.1.2.8 2002/03/12 13:42:23 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:
favour Kruskal's, because we make an extra AVL tree of edges sorted on
weights (metric). That tree only has to be updated when an edge is added or
removed, and during the MST algorithm we just have go linearly through that
- tree.
+ tree, adding safe edges until #edges = #nodes - 1. The implementation here
+ however is not so fast, because I tried to avoid having to make a forest and
+ merge trees.
For the SSSP algorithm Dijkstra's seems to be a nice choice. Currently a
simple breadth-first search is presented here.
destination address and port of a node if possible.
*/
-#include <syslog.h>
-#include "config.h"
-#include <string.h>
-#if defined(HAVE_FREEBSD) || defined(HAVE_OPENBSD)
- #include <sys/param.h>
-#endif
-#include <netinet/in.h>
-
-#include <avl_tree.h>
-#include <utils.h>
+#include "system.h"
+#include "avl_tree.h"
+#include "config.h"
+#include "connection.h"
+#include "device.h"
+#include "edge.h"
+#include "graph.h"
+#include "logger.h"
#include "netutl.h"
#include "node.h"
-#include "edge.h"
-#include "connection.h"
+#include "process.h"
+#include "protocol.h"
+#include "subnet.h"
+#include "utils.h"
+#include "xalloc.h"
-#include "system.h"
+static bool graph_changed = true;
-/* Kruskal's minimum spanning tree algorithm.
- Running time: O(E)
- Edges are already sorted on weight.
+/* 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;
- edge_t *e;
- node_t *n;
- connection_t *c;
+static 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;
+ bool skipped;
+
+ /* Clear MST status on connections */
+
+ for(node = connection_tree->head; node; node = node->next) {
+ c = node->data;
+ c->status.mst = false;
+ }
- /* Clear MST status on connections */
+ /* Do we have something to do at all? */
- for(node = connection_tree->head; node; node = node->next)
- {
- c = (connection_t *)node->data;
- c->status.mst = 0;
- }
+ if(!edge_weight_tree->head)
+ return;
- /* Do we have something to do at all? */
-
- if(!edge_weight_tree->head)
- return;
+ ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Running Kruskal's algorithm:");
- /* Clear visited status on nodes */
+ /* Clear visited status on nodes */
- for(node = node_tree->head; node; node = node->next)
- {
- n = (node_t *)node->data;
- n->status.visited = 0;
- }
+ for(node = node_tree->head; node; node = node->next) {
+ n = node->data;
+ n->status.visited = false;
+ nodes++;
+ }
+
+ /* Starting point */
+
+ for(node = edge_weight_tree->head; node; node = node->next) {
+ e = node->data;
+ if(e->from->status.reachable) {
+ e->from->status.visited = true;
+ break;
+ }
+ }
- /* Starting point */
-
- ((edge_t *)edge_weight_tree->head->data)->from.node->status.visited = 1;
+ /* Add safe edges */
- /* Add safe edges */
+ for(skipped = false, node = edge_weight_tree->head; node; node = next) {
+ next = node->next;
+ e = node->data;
- for(node = edge_weight_tree->head; node; node = node->next)
- {
- e = (edge_t *)node->data;
+ if(!e->reverse || e->from->status.visited == e->to->status.visited) {
+ skipped = true;
+ continue;
+ }
- if(e->from.node->status.visited && e->to.node->status.visited)
- continue;
+ e->from->status.visited = true;
+ e->to->status.visited = true;
- e->from.node->status.visited = 1;
- e->to.node->status.visited = 1;
- if(e->connection)
- e->connection->status.mst = 1;
- }
+ if(e->connection)
+ e->connection->status.mst = true;
+
+ if(e->reverse->connection)
+ e->reverse->connection->status.mst = true;
+
+ safe_edges++;
+
+ ifdebug(SCARY_THINGS) logger(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;
+ continue;
+ }
+ }
+
+ ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Done, counted %d nodes and %d safe edges.", nodes,
+ safe_edges);
}
/* Implementation of a simple breadth-first search algorithm.
Running time: O(E)
*/
-void sssp_bfs(void)
-{
- avl_node_t *node, *from, *next, *to;
- edge_t *e;
- node_t *n;
- halfconnection_t to_hc, from_hc;
- 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) /* "from" is the node from which we start */
- {
- next = from->next;
- n = (node_t *)from->data;
-
- for(to = n->edge_tree->head; to; to = to->next) /* "to" is the edge connected to "from" */
- {
- e = (edge_t *)to->data;
-
- if(e->from.node == n) /* "from_hc" is the halfconnection with .node == from */
- to_hc = e->to, from_hc = e->from;
- else
- to_hc = e->from, from_hc = e->to;
-
- if(!to_hc.node->status.visited)
- {
- to_hc.node->status.visited = 1;
- to_hc.node->nexthop = (n->nexthop == myself) ? to_hc.node : n->nexthop;
- to_hc.node->via = (e->options & OPTION_INDIRECT || n->via != n) ? n->via : to_hc.node;
- to_hc.node->options = e->options;
- if(sockaddrcmp(&to_hc.node->address, &to_hc.udpaddress))
- {
- node = avl_unlink(node_udp_tree, to_hc.node);
- to_hc.node->address = to_hc.udpaddress;
- if(to_hc.node->hostname)
- free(to_hc.node->hostname);
- to_hc.node->hostname = sockaddr2hostname(&to_hc.udpaddress);
- avl_insert_node(node_udp_tree, node);
- }
- node = avl_alloc_node();
- node->data = to_hc.node;
- avl_insert_before(todo_tree, from, node);
- }
- }
-
- avl_delete_node(todo_tree, from);
- }
- }
-
- avl_free_tree(todo_tree);
-
- /* Check reachability status. */
-
- for(node = node_tree->head; node; node = next)
- {
- next = node->next;
- n = (node_t *)node->data;
-
- if(n->status.visited)
- {
- if(!n->status.reachable)
- {
- if(debug_lvl >= DEBUG_TRAFFIC)
- syslog(LOG_DEBUG, _("Node %s (%s) became reachable"), n->name, n->hostname);
- n->status.reachable = 1;
+static void sssp_bfs(void) {
+ avl_node_t *node, *next, *to;
+ edge_t *e;
+ node_t *n;
+ list_t *todo_list;
+ list_node_t *from, *todonext;
+ bool indirect;
+ char *name;
+ char *address, *port;
+ char *envp[7];
+ int i;
+
+ todo_list = list_alloc(NULL);
+
+ /* Clear visited status on nodes */
+
+ for(node = node_tree->head; node; node = node->next) {
+ n = node->data;
+ n->status.visited = false;
+ n->status.indirect = true;
+ }
+
+ /* Begin with myself */
+
+ myself->status.visited = true;
+ myself->status.indirect = false;
+ myself->nexthop = myself;
+ myself->prevedge = NULL;
+ myself->via = myself;
+ list_insert_head(todo_list, myself);
+
+ /* Loop while todo_list is filled */
+
+ for(from = todo_list->head; from; from = todonext) { /* "from" is the node from which we start */
+ n = from->data;
+
+ for(to = n->edge_tree->head; to; to = to->next) { /* "to" is the edge connected to "from" */
+ e = to->data;
+
+ 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.
+ */
+
+ indirect = n->status.indirect || e->options & OPTION_INDIRECT;
+
+ if(e->to->status.visited
+ && (!e->to->status.indirect || indirect))
+ continue;
+
+ e->to->status.visited = true;
+ e->to->status.indirect = indirect;
+ e->to->nexthop = (n->nexthop == myself) ? e->to : n->nexthop;
+ e->to->prevedge = e;
+ e->to->via = indirect ? n->via : e->to;
+ e->to->options = e->options;
+
+ if(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);
+ }
+
+ todonext = from->next;
+ list_delete_node(todo_list, from);
}
- }
- else
- {
- if(n->status.reachable)
- {
- if(debug_lvl >= DEBUG_TRAFFIC)
- syslog(LOG_DEBUG, _("Node %s (%s) became unreachable"), n->name, n->hostname);
- n->status.reachable = 0;
- n->status.validkey = 0;
- n->status.waitingforkey = 0;
- n->sent_seqno = 0;
+
+ list_free(todo_list);
+
+ /* Check reachability status. */
+
+ for(node = node_tree->head; node; node = next) {
+ next = node->next;
+ n = node->data;
+
+ if(n->status.visited != n->status.reachable) {
+ n->status.reachable = !n->status.reachable;
+
+ if(n->status.reachable) {
+ ifdebug(TRAFFIC) logger(LOG_DEBUG, "Node %s (%s) became reachable",
+ n->name, n->hostname);
+ } else {
+ ifdebug(TRAFFIC) logger(LOG_DEBUG, "Node %s (%s) became unreachable",
+ n->name, n->hostname);
+ }
+
+ /* TODO: only clear status.validkey if node is unreachable? */
+
+ n->status.validkey = false;
+ n->last_req_key = 0;
+
+ n->maxmtu = MTU;
+ n->minmtu = 0;
+ n->mtuprobes = 0;
+
+ if(n->mtuevent) {
+ event_del(n->mtuevent);
+ n->mtuevent = 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);
+ envp[6] = NULL;
+
+ 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(i = 0; i < 6; 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) {
+ send_ans_key(n);
+ }
+ }
}
- }
- }
}
-void graph(void)
-{
- mst_kruskal();
- sssp_bfs();
+void graph(void) {
+ subnet_cache_flush();
+ sssp_bfs();
+ mst_kruskal();
+ graph_changed = true;
+}
+
+
+
+/* Dump nodes and edges to a graphviz file.
+
+ The file can be converted to an image with
+ dot -Tpng graph_filename -o image_filename.png -Gconcentrate=true
+*/
+
+void dump_graph(void) {
+ avl_node_t *node;
+ node_t *n;
+ edge_t *e;
+ char *filename = NULL, *tmpname = NULL;
+ FILE *file, *pipe;
+
+ if(!graph_changed || !get_config_string(lookup_config(config_tree, "GraphDumpFile"), &filename))
+ return;
+
+ graph_changed = false;
+
+ ifdebug(PROTOCOL) logger(LOG_NOTICE, "Dumping graph");
+
+ if(filename[0] == '|') {
+ file = pipe = popen(filename + 1, "w");
+ } else {
+ xasprintf(&tmpname, "%s.new", filename);
+ file = fopen(tmpname, "w");
+ }
+
+ if(!file) {
+ logger(LOG_ERR, "Unable to open graph dump file %s: %s", filename, strerror(errno));
+ free(tmpname);
+ return;
+ }
+
+ fprintf(file, "digraph {\n");
+
+ /* dump all nodes first */
+ for(node = node_tree->head; node; node = node->next) {
+ n = node->data;
+ fprintf(file, " %s [label = \"%s\"];\n", n->name, n->name);
+ }
+
+ /* now dump all edges */
+ for(node = edge_weight_tree->head; node; node = node->next) {
+ e = node->data;
+ fprintf(file, " %s -> %s;\n", e->from->name, e->to->name);
+ }
+
+ fprintf(file, "}\n");
+
+ if(filename[0] == '|') {
+ pclose(pipe);
+ } else {
+ fclose(file);
+#ifdef HAVE_MINGW
+ unlink(filename);
+#endif
+ rename(tmpname, filename);
+ free(tmpname);
+ }
}
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