/*
graph.c -- graph algorithms
- Copyright (C) 2001-2009 Guus Sliepen <guus@tinc-vpn.org>,
- 2001-2005 Ivo Timmermans
+ 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
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 "system.h"
-#include "splay_tree.h"
-#include "config.h"
#include "connection.h"
-#include "device.h"
#include "edge.h"
+#include "graph.h"
+#include "list.h"
#include "logger.h"
+#include "meshlink_internal.h"
#include "netutl.h"
#include "node.h"
-#include "process.h"
-#include "subnet.h"
+#include "protocol.h"
#include "utils.h"
#include "xalloc.h"
+#include "graph.h"
-/* Implementation of Kruskal's algorithm.
+/* Implementation of a simple breadth-first search algorithm.
Running time: O(E)
- Please note that sorting on weight is already done by add_edge().
-*/
-
-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:");
+static void sssp_bfs(meshlink_handle_t *mesh) {
+ list_t *todo_list = list_alloc(NULL);
/* Clear visited status on nodes */
- for(node = node_tree->head; node; node = node->next) {
- n = node->data;
+ for splay_each(node_t, n, mesh->nodes) {
n->status.visited = false;
- n->status.indirect = true;
n->distance = -1;
}
- /* Begin with myself */
+ /* Begin with mesh->self */
- myself->status.indirect = false;
- myself->nexthop = myself;
- myself->via = myself;
- myself->distance = 0;
- list_insert_head(todo_list, myself);
+ 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 */
- while(todo_list->head) {
- n = NULL;
- nnode = NULL;
-
- /* Select node from todo_list with smallest distance */
+ 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);
- 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;
- }
+ if(n->distance < 0) {
+ abort();
}
- /* 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:
-
- - 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.
- */
-
- if(e->to->distance < 0)
- list_insert_tail(todo_list, e->to);
-
- indirect = n->status.indirect || e->options & OPTION_INDIRECT || ((n != myself) && sockaddrcmp(&n->address, &e->reverse->address));
-
- if(e->to->distance >= 0 && (!e->to->status.indirect || indirect) && e->to->distance <= n->distance + e->weight)
+ for splay_each(edge_t, e, n->edge_tree) { /* "e" is the edge connected to "from" */
+ if(!e->reverse) {
continue;
-
- 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;
-
- 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);
-
- if(e->to->hostname)
- free(e->to->hostname);
-
- e->to->hostname = sockaddr2hostname(&e->to->address);
-
- if(node)
- splay_insert_node(node_udp_tree, node);
-
- 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) {
- 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;
- }
-
- /* 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))
+ && (e->to->distance != n->distance + 1 || e->weight >= e->to->prevedge->weight)) {
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;
+ e->to->nexthop = (n->nexthop == mesh->self) ? e->to : n->nexthop;
+ e->to->prevedge = e;
+ e->to->distance = n->distance + 1;
- if(e->to->address.sa.sa_family == AF_UNSPEC && e->address.sa.sa_family != AF_UNKNOWN)
- update_node_udp(e->to, &e->address);
+ 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);
}
- todonext = from->next;
- list_delete_node(todo_list, from);
+ 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);
}
-void check_reachability() {
- splay_node_t *node, *next;
- node_t *n;
- char *name;
- char *address, *port;
- char *envp[7];
- int i;
-
+static void check_reachability(meshlink_handle_t *mesh) {
/* Check reachability status. */
- for(node = node_tree->head; node; node = next) {
- next = node->next;
- n = node->data;
+ 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;
-
- 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);
+ 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;
- 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;
+ timeout_del(&mesh->loop, &n->mtutimeout);
- 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);
+ if(!n->status.blacklisted) {
+ update_node_status(mesh, n);
+ }
- for(i = 0; i < 6; i++)
- free(envp[i]);
+ 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);
+ }
+ }
- subnet_update(n, NULL, n->status.reachable);
+ if(n->utcp) {
+ utcp_offline(n->utcp, !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
-*/
+ if(mesh->reachable != reachable) {
+ if(!reachable) {
+ mesh->last_unreachable = mesh->loop.now.tv_sec;
-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;
- }
+ if(mesh->threadstarted) {
+ timeout_set(&mesh->loop, &mesh->periodictimer, &(struct timespec) {
+ 0, prng(mesh, TIMER_FUDGE)
+ });
+ }
+ }
- /* 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;
+ mesh->reachable = reachable;
}
-
- if(evbuffer_add_printf(out, "}\n") == -1)
- return errno;
-
- return 0;
}
-void graph(void) {
- subnet_cache_flush();
- sssp_dijkstra();
- check_reachability();
- mst_kruskal();
+void graph(meshlink_handle_t *mesh) {
+ sssp_bfs(mesh);
+ check_reachability(mesh);
}
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