/*
graph.c -- graph algorithms
- Copyright (C) 2001-2002 Guus Sliepen <guus@sliepen.eu.org>,
- 2001-2002 Ivo Timmermans <ivo@o2w.nl>
+ Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
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 1.1.2.18 2002/09/09 19:39:58 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.
- 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 "config.h"
-
-#include <stdio.h>
-#include <syslog.h>
-#include "config.h"
-#include <string.h>
-#ifdef HAVE_SYS_PARAM_H
- #include <sys/param.h>
-#endif
-#include <netinet/in.h>
-
-#include <avl_tree.h>
-#include <utils.h>
+#include "system.h"
+#include "connection.h"
+#include "edge.h"
+#include "graph.h"
+#include "list.h"
+#include "logger.h"
+#include "meshlink_internal.h"
#include "netutl.h"
#include "node.h"
-#include "edge.h"
-#include "connection.h"
-#include "process.h"
-#include "device.h"
-
-#include "system.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 MST status on connections */
-
- for(node = connection_tree->head; node; node = node->next)
- {
- c = (connection_t *)node->data;
- c->status.mst = 0;
- }
-
- /* Do we have something to do at all? */
-
- if(!edge_weight_tree->head)
- return;
-
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- syslog(LOG_DEBUG, "Running Kruskal's algorithm:");
-
- /* 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;
-
- /* Add safe edges */
-
- for(skipped = 0, node = edge_weight_tree->head; node; node = next)
- {
- next = node->next;
- e = (edge_t *)node->data;
-
- if(!e->reverse || 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;
- if(e->reverse->connection)
- e->reverse->connection->status.mst = 1;
-
- safe_edges++;
-
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- syslog(LOG_DEBUG, " Adding edge %s - %s weight %d", e->from->name, e->to->name, e->weight);
-
- if(skipped)
- {
- skipped = 0;
- next = edge_weight_tree->head;
- continue;
- }
- }
-
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- syslog(LOG_DEBUG, "Done, counted %d nodes and %d safe edges.", nodes, safe_edges);
-}
+#include "protocol.h"
+#include "utils.h"
+#include "xalloc.h"
+#include "graph.h"
/* 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;
- avl_tree_t *todo_tree;
- int indirect;
- char *name;
- char *address, *port;
- char *envp[7];
- int i;
-
- 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;
- n->status.indirect = 1;
- }
-
- /* Begin with myself */
-
- myself->status.visited = 1;
- myself->status.indirect = 0;
- 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->reverse)
- continue;
-
- /* Situation:
-
- /
- /
- ------(n)-----(e->to)
- \
- \
-
- 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_tree 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 = 1;
- 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(sockaddrcmp(&e->to->address, &e->address))
- {
- node = avl_unlink(node_udp_tree, e->to);
- e->to->address = e->address;
- if(e->to->hostname)
- free(e->to->hostname);
- e->to->hostname = sockaddr2hostname(&e->to->address);
- avl_insert_node(node_udp_tree, node);
- }
- node = avl_alloc_node();
- node->data = e->to;
- 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 != n->status.reachable)
- {
- n->status.reachable = !n->status.reachable;
- if(debug_lvl >= DEBUG_TRAFFIC)
- if(n->status.reachable)
- syslog(LOG_DEBUG, _("Node %s (%s) became reachable"), n->name, n->hostname);
- else
- syslog(LOG_DEBUG, _("Node %s (%s) became unreachable"), n->name, n->hostname);
-
- n->status.validkey = 0;
- n->status.waitingforkey = 0;
-
- asprintf(&envp[0], "NETNAME=%s", netname?:"");
- asprintf(&envp[1], "DEVICE=%s", device?:"");
- asprintf(&envp[2], "INTERFACE=%s", interface?:"");
- asprintf(&envp[3], "NODE=%s", n->name);
- sockaddr2str(&n->address, &address, &port);
- asprintf(&envp[4], "REMOTEADDRESS=%s", address);
- asprintf(&envp[5], "REMOTEPORT=%s", port);
- envp[6] = NULL;
-
- asprintf(&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 < 7; i++)
- free(envp[i]);
- }
- }
+static void sssp_bfs(meshlink_handle_t *mesh) {
+ list_t *todo_list = list_alloc(NULL);
+
+ /* Clear visited status on nodes */
+
+ for splay_each(node_t, n, mesh->nodes) {
+ n->status.visited = false;
+ n->distance = -1;
+ }
+
+ /* Begin with mesh->self */
+
+ mesh->self->status.visited = mesh->threadstarted;
+ mesh->self->nexthop = mesh->self;
+ mesh->self->prevedge = NULL;
+ mesh->self->distance = 0;
+ list_insert_head(todo_list, mesh->self);
+
+ /* Loop while todo_list is filled */
+
+ for list_each(node_t, n, todo_list) { /* "n" is the node from which we start */
+ logger(mesh, MESHLINK_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.
+ */
+
+ if(e->to->status.visited
+ && (e->to->distance != n->distance + 1 || e->weight >= e->to->prevedge->weight)) {
+ continue;
+ }
+
+ e->to->status.visited = true;
+ e->to->nexthop = (n->nexthop == mesh->self) ? e->to : n->nexthop;
+ e->to->prevedge = e;
+ 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(mesh, 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(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->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? */
+
+ 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.blacklisted) {
+ update_node_status(mesh, n);
+ }
+
+ if(!n->status.reachable) {
+ update_node_udp(mesh, n, NULL);
+ n->status.broadcast = false;
+ } else if(n->connection) {
+ 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(void)
-{
- mst_kruskal();
- sssp_bfs();
+void graph(meshlink_handle_t *mesh) {
+ sssp_bfs(mesh);
+ check_reachability(mesh);
}
projects / meshlink / blobdiff