/*
graph.c -- graph algorithms
- Copyright (C) 2001-2002 Guus Sliepen <guus@sliepen.warande.net>,
- 2001-2002 Ivo Timmermans <itimmermans@bigfoot.com>
+ Copyright (C) 2001-2009 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 "splay_tree.h"
+#include "config.h"
+#include "connection.h"
+#include "device.h"
+#include "edge.h"
+#include "logger.h"
#include "netutl.h"
#include "node.h"
-#include "edge.h"
-#include "connection.h"
-
-#include "system.h"
+#include "process.h"
+#include "subnet.h"
+#include "utils.h"
+#include "xalloc.h"
-/* Kruskal's minimum spanning tree algorithm.
+/* Implementation of Kruskal's algorithm.
Running time: O(E)
- Edges are already sorted on weight.
+ 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;
+void mst_kruskal(void) {
+ splay_node_t *node, *next;
+ edge_t *e;
+ node_t *n;
+ connection_t *c;
+
+ /* Clear MST status on connections */
+
+ for(node = connection_tree->head; node; node = node->next) {
+ c = node->data;
+ c->status.mst = false;
+ }
+
+ ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Running Kruskal's algorithm:");
+
+ /* Clear visited status on nodes */
+
+ for(node = node_tree->head; node; node = node->next) {
+ n = node->data;
+ n->status.visited = false;
+ }
+
+ /* Add safe edges */
+
+ for(node = edge_weight_tree->head; node; node = next) {
+ next = node->next;
+ e = node->data;
+
+ if(!e->reverse || (e->from->status.visited && e->to->status.visited))
+ 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;
+
+ ifdebug(SCARY_THINGS) logger(LOG_DEBUG, " Adding edge %s - %s weight %d", e->from->name,
+ e->to->name, e->weight);
+ }
+}
+
+/* Implementation of Dijkstra's algorithm.
+ Running time: O(N^2)
+*/
+
+void sssp_dijkstra(void) {
+ splay_node_t *node, *to;
+ edge_t *e;
+ node_t *n, *m;
+ list_t *todo_list;
+ list_node_t *lnode, *nnode;
+ bool indirect;
+
+ todo_list = list_alloc(NULL);
+
+ ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Running Dijkstra's algorithm:");
+
+ /* 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;
+ n->distance = -1;
+ }
+
+ /* Begin with myself */
+
+ myself->status.indirect = false;
+ myself->nexthop = myself;
+ myself->via = myself;
+ myself->distance = 0;
+ list_insert_head(todo_list, myself);
+
+ /* Loop while todo_list is filled */
+
+ while(todo_list->head) {
+ n = NULL;
+ nnode = NULL;
+
+ /* Select node from todo_list with smallest distance */
+
+ for(lnode = todo_list->head; lnode; lnode = lnode->next) {
+ m = lnode->data;
+ if(!n || m->status.indirect < n->status.indirect || m->distance < n->distance) {
+ n = m;
+ nnode = lnode;
+ }
+ }
+
+ /* Mark this node as visited and remove it from the todo_list */
+
+ n->status.visited = true;
+ list_unlink_node(todo_list, nnode);
+
+ /* Update distance of neighbours and add them to the todo_list */
+
+ for(to = n->edge_tree->head; to; to = to->next) { /* "to" is the edge connected to "from" */
+ e = to->data;
+
+ if(e->to->status.visited || !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:
- /* Clear MST status on connections */
+ - If e->reverse->address != n->address, then e->to is probably
+ not reachable for the nodes left of n. We do as if the indirectdata
+ flag is set on edge e.
+ - If edge e provides for better reachability of e->to, update e->to.
+ */
- for(node = connection_tree->head; node; node = node->next)
- {
- c = (connection_t *)node->data;
- c->status.mst = 0;
- }
+ if(e->to->distance < 0)
+ list_insert_tail(todo_list, e->to);
- /* Do we have something to do at all? */
-
- if(!edge_weight_tree->head)
- return;
+ indirect = n->status.indirect || e->options & OPTION_INDIRECT || ((n != myself) && sockaddrcmp(&n->address, &e->reverse->address));
- /* Clear visited status on nodes */
+ if(e->to->distance >= 0 && (!e->to->status.indirect || indirect) && e->to->distance <= n->distance + e->weight)
+ continue;
- for(node = node_tree->head; node; node = node->next)
- {
- n = (node_t *)node->data;
- n->status.visited = 0;
- }
+ e->to->distance = n->distance + e->weight;
+ e->to->status.indirect = indirect;
+ e->to->nexthop = (n->nexthop == myself) ? e->to : n->nexthop;
+ e->to->via = indirect ? n->via : e->to;
+ e->to->options = e->options;
- /* Starting point */
-
- ((edge_t *)edge_weight_tree->head->data)->from.node->status.visited = 1;
+ if(sockaddrcmp(&e->to->address, &e->address)) {
+ node = splay_unlink(node_udp_tree, e->to);
+ sockaddrfree(&e->to->address);
+ sockaddrcpy(&e->to->address, &e->address);
- /* Add safe edges */
+ if(e->to->hostname)
+ free(e->to->hostname);
- for(node = edge_weight_tree->head; node; node = node->next)
- {
- e = (edge_t *)node->data;
+ e->to->hostname = sockaddr2hostname(&e->to->address);
- if(e->from.node->status.visited && e->to.node->status.visited)
- continue;
+ if(node)
+ splay_insert_node(node_udp_tree, node);
- e->from.node->status.visited = 1;
- e->to.node->status.visited = 1;
- if(e->connection)
- e->connection->status.mst = 1;
- }
+ if(e->to->options & OPTION_PMTU_DISCOVERY) {
+ e->to->mtuprobes = 0;
+ e->to->minmtu = 0;
+ e->to->maxmtu = MTU;
+ if(e->to->status.validkey)
+ send_mtu_probe(e->to);
+ }
+ }
+
+ ifdebug(SCARY_THINGS) logger(LOG_DEBUG, " Updating edge %s - %s weight %d distance %d", e->from->name,
+ e->to->name, e->weight, e->to->distance);
+ }
+ }
+
+ list_free(todo_list);
}
/* 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;
+void sssp_bfs(void) {
+ splay_node_t *node, *to;
+ edge_t *e;
+ node_t *n;
+ list_t *todo_list;
+ list_node_t *from, *todonext;
+ bool indirect;
+
+ 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;
}
- }
- 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;
+
+ /* Begin with myself */
+
+ myself->status.visited = true;
+ myself->status.indirect = false;
+ myself->nexthop = myself;
+ 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 e->reverse->address != n->address, then e->to is probably
+ not reachable for the nodes left of n. We do as if the indirectdata
+ flag is set on edge e.
+ - 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
+ || ((n != myself) && sockaddrcmp(&n->address, &e->reverse->address));
+
+ 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->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);
}
- }
- }
+
+ list_free(todo_list);
+}
+
+void check_reachability() {
+ splay_node_t *node, *next;
+ node_t *n;
+ char *name;
+ char *address, *port;
+ char *envp[7];
+ int i;
+
+ /* 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->status.waitingforkey = false;
+
+ n->maxmtu = MTU;
+ n->minmtu = 0;
+ n->mtuprobes = 0;
+
+ event_del(&n->mtuevent);
+
+ 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);
+ }
+ }
+}
+
+/* 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
+*/
+
+int dump_graph(struct evbuffer *out) {
+ splay_node_t *node;
+ node_t *n;
+ edge_t *e;
+
+ if(evbuffer_add_printf(out, "digraph {\n") == -1)
+ return errno;
+
+ /* dump all nodes first */
+ for(node = node_tree->head; node; node = node->next) {
+ n = node->data;
+ if(evbuffer_add_printf(out, " %s [label = \"%s\"];\n",
+ n->name, n->name) == -1)
+ return errno;
+ }
+
+ /* now dump all edges */
+ for(node = edge_weight_tree->head; node; node = node->next) {
+ e = node->data;
+ if(evbuffer_add_printf(out, " %s -> %s;\n",
+ e->from->name, e->to->name) == -1)
+ return errno;
+ }
+
+ if(evbuffer_add_printf(out, "}\n") == -1)
+ return errno;
+
+ return 0;
}
-void graph(void)
-{
- mst_kruskal();
- sssp_bfs();
+void graph(void) {
+ subnet_cache_flush();
+ sssp_dijkstra();
+ check_reachability();
+ mst_kruskal();
}
projects / tinc / blobdiff