--- /dev/null
+/*
+ autoconnect.c -- automatic connection establishment
+ Copyright (C) 2019 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
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ 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.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "system.h"
+
+#include "connection.h"
+#include "list.h"
+#include "logger.h"
+#include "net.h"
+#include "node.h"
+#include "xalloc.h"
+
+/* Make an outgoing connection if possible */
+static bool make_outgoing(meshlink_handle_t *mesh, node_t *n) {
+ if(!n || n->connection) {
+ return false;
+ }
+
+ n->last_connect_try = mesh->loop.now.tv_sec;
+ logger(mesh, MESHLINK_DEBUG, "Autoconnect trying to connect to %s", n->name);
+
+ /* check if there is already a connection attempt to this node */
+ for list_each(outgoing_t, outgoing, mesh->outgoings) {
+ if(outgoing->node == n) {
+ logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since it is an outgoing connection already");
+ return false;
+ }
+ }
+
+ if(!n->status.reachable && !node_read_public_key(mesh, n)) {
+ logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since we don't know this node's public key");
+ return false;
+ }
+
+ logger(mesh, MESHLINK_DEBUG, "Autoconnecting to %s", n->name);
+ outgoing_t *outgoing = xzalloc(sizeof(outgoing_t));
+ outgoing->node = n;
+ list_insert_tail(mesh->outgoings, outgoing);
+ setup_outgoing_connection(mesh, outgoing);
+ return true;
+}
+
+/* Determine if node n is a better candidate for making an early connection to than node m. */
+static bool compare_candidates(node_t *n, node_t *m) {
+ /* Check if the last connection attempt was successful */
+ bool n_successful = n->last_successful_connection > n->last_connect_try;
+ bool m_successful = n->last_successful_connection > n->last_connect_try;
+
+ if(n_successful != m_successful) {
+ return n_successful;
+ } else {
+ if(n_successful) {
+ /* If both were successfully connected to, prefer the most recent one */
+ return n->last_successful_connection > m->last_successful_connection;
+ } else {
+ /* If the last connections were not successful, prefer the one we least recently tried to connect to. */
+ return n->last_connect_try < m->last_connect_try;
+ }
+ }
+}
+
+/* Try to connect to any candidate in the same or better device class. Prefer recently connected-to nodes first. */
+static bool make_eager_connection(meshlink_handle_t *mesh) {
+ node_t *candidate = NULL;
+
+ for splay_each(node_t, n, mesh->nodes) {
+ if(n == mesh->self || n->devclass > mesh->devclass || n->connection || n->status.blacklisted) {
+ continue;
+ }
+
+ if(!candidate) {
+ candidate = n;
+ continue;
+ }
+
+ if(compare_candidates(n, candidate)) {
+ candidate = n;
+ }
+ }
+
+ return make_outgoing(mesh, candidate);
+}
+
+/* Try to connect to balance connections to different device classes. Prefer recently connected-to nodes first. */
+static bool make_better_connection(meshlink_handle_t *mesh) {
+ const unsigned int min_connects = mesh->dev_class_traits[mesh->devclass].min_connects;
+
+ for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
+ unsigned int connects = 0;
+
+ for list_each(connection_t, c, mesh->connections) {
+ if(c->status.active && c->node && c->node->devclass == devclass) {
+ connects += 1;
+
+ if(connects >= min_connects) {
+ break;
+ }
+ }
+ }
+
+ if(connects >= min_connects) {
+ continue;
+ }
+
+ node_t *candidate = NULL;
+
+ for splay_each(node_t, n, mesh->nodes) {
+ if(n == mesh->self || n->devclass != devclass || n->connection || n->status.blacklisted) {
+ continue;
+ }
+
+ if(!candidate) {
+ candidate = n;
+ continue;
+ }
+
+ if(compare_candidates(n, candidate)) {
+ candidate = n;
+ }
+ }
+
+ if(make_outgoing(mesh, candidate)) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
+/* Disconnect from a random node that doesn't weaken the graph, and cancel redundant outgoings */
+static void disconnect_redundant(meshlink_handle_t *mesh) {
+ int count = 0;
+
+ for list_each(connection_t, c, mesh->connections) {
+ if(!c->status.active || !c->outgoing || !c->node) {
+ continue;
+ }
+
+ if(c->node->edge_tree->count < 2) {
+ continue;
+ }
+
+ count++;
+ }
+
+ if(!count) {
+ return;
+ }
+
+ int r = rand() % count;
+
+ for list_each(connection_t, c, mesh->connections) {
+ if(!c->status.active || !c->outgoing || !c->node) {
+ continue;
+ }
+
+ if(c->node->edge_tree->count < 2) {
+ continue;
+ }
+
+ if(r--) {
+ continue;
+ }
+
+ logger(mesh, MESHLINK_DEBUG, "Autodisconnecting from %s", c->name);
+ list_delete(mesh->outgoings, c->outgoing);
+ c->outgoing = NULL;
+ terminate_connection(mesh, c, c->status.active);
+ break;
+ }
+
+ for list_each(outgoing_t, o, mesh->outgoings) {
+ if(!o->node->connection) {
+ list_delete_node(mesh->outgoings, node);
+ }
+ }
+}
+
+static void heal_partitions(meshlink_handle_t *mesh) {
+ /* Select a random known node. The rationale is that if there are many
+ * reachable nodes, and only a few unreachable nodes, we don't want all
+ * reachable nodes to try to connect to the unreachable ones at the
+ * same time. This way, we back off automatically. Conversely, if there
+ * are only a few reachable nodes, and many unreachable ones, we're
+ * going to try harder to connect to them. */
+
+ int r = rand() % mesh->nodes->count;
+
+ for splay_each(node_t, n, mesh->nodes) {
+ if(r--) {
+ continue;
+ }
+
+ if(n == mesh->self || n->connection || n->status.reachable || n->status.blacklisted) {
+ return;
+ }
+
+ /* Are we already trying to make an outgoing connection to it? If so, return. */
+ for list_each(outgoing_t, outgoing, mesh->outgoings) {
+ if(outgoing->node == n) {
+ return;
+ }
+ }
+
+ make_outgoing(mesh, n);
+ return;
+ }
+
+}
+
+unsigned int do_autoconnect(meshlink_handle_t *mesh) {
+ /* Count the number of active connections. */
+
+ unsigned int cur_connects = 0;
+
+ for list_each(connection_t, c, mesh->connections) {
+ if(c->status.active) {
+ cur_connects += 1;
+ }
+ }
+
+ /* We don't have the minimum number of connections? Eagerly try to make a new one. */
+
+ const unsigned int max_connects = mesh->dev_class_traits[mesh->devclass].max_connects;
+ const unsigned int min_connects = mesh->dev_class_traits[mesh->devclass].min_connects;
+
+ logger(mesh, MESHLINK_DEBUG, "do_autoconnect() %d %d %d\n", cur_connects, min_connects, max_connects);
+
+ if(cur_connects < min_connects) {
+ make_eager_connection(mesh);
+ } else if(cur_connects < max_connects) {
+ /* Otherwise, try to improve. */
+ make_better_connection(mesh);
+ }
+
+ if (cur_connects >= max_connects) {
+ disconnect_redundant(mesh);
+ }
+
+ heal_partitions(mesh);
+
+ return cur_connects;
+}
#include "system.h"
-#include "utils.h"
+#include "autoconnect.h"
#include "conf.h"
#include "connection.h"
#include "graph.h"
#include "net.h"
#include "netutl.h"
#include "protocol.h"
+#include "utils.h"
#include "xalloc.h"
#include <assert.h>
});
}
-// devclass asc, last_successfull_connection desc
-static int node_compare_devclass_asc_lsc_desc(const void *a, const void *b) {
- const node_t *na = a, *nb = b;
-
- if(na->devclass < nb->devclass) {
- return -1;
- }
-
- if(na->devclass > nb->devclass) {
- return 1;
- }
-
- if(na->last_successfull_connection == nb->last_successfull_connection) {
- return 0;
- }
-
- if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection) {
- return -1;
- }
-
- if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection) {
- return 1;
- }
-
- if(na < nb) {
- return -1;
- }
-
- if(na > nb) {
- return 1;
- }
-
- return 0;
-}
-
-// last_successfull_connection desc
-static int node_compare_lsc_desc(const void *a, const void *b) {
- const node_t *na = a, *nb = b;
-
- if(na->last_successfull_connection == nb->last_successfull_connection) {
- return 0;
- }
-
- if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection) {
- return -1;
- }
-
- if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection) {
- return 1;
- }
-
- if(na < nb) {
- return -1;
- }
-
- if(na > nb) {
- return 1;
- }
-
- return 0;
-}
-
-// devclass desc
-static int node_compare_devclass_desc(const void *a, const void *b) {
- const node_t *na = a, *nb = b;
-
- if(na->devclass < nb->devclass) {
- return -1;
- }
-
- if(na->devclass > nb->devclass) {
- return 1;
- }
-
- if(na < nb) {
- return -1;
- }
-
- if(na > nb) {
- return 1;
- }
-
- return 0;
-}
-
-
-/*
-
-autoconnect()
-{
- timeout = 5
-
- // find the best one for initial connect
-
- if cur < min
- newcon =
- first from nodes
- where dclass <= my.dclass and !connection and (timestamp - last_retry) > retry_timeout
- order by dclass asc, last_connection desc
- if newcon
- timeout = 0
- goto connect
-
-
- // find better nodes to connect to: in case we have less than min connections within [BACKBONE, i] and there are nodes which we are not connected to within the range
-
- if min <= cur < max
- j = 0
- for i = BACKBONE to my.dclass
- j += count(from connections where node.dclass = i)
- if j < min
- newcon =
- first from nodes
- where dclass = i and !connection and (timestamp - last_retry) > retry_timeout
- order by last_connection desc
- if newcon
- goto connect
- else
- break
-
-
- // heal partitions
-
- if min <= cur < max
- newcon =
- first from nodes
- where dclass <= my.dclass and !reachable and (timestamp - last_retry) > retry_timeout
- order by dclass asc, last_connection desc
- if newcon
- goto connect
-
-
- // connect
-
-connect:
- if newcon
- connect newcon
-
-
- // disconnect outgoing connections in case we have more than min connections within [BACKBONE, i] and there are nodes which we are connected to within the range [i, PORTABLE]
-
- if min < cur <= max
- j = 0
- for i = BACKBONE to my.dclass
- j += count(from connections where node.dclass = i)
- if min < j
- delcon =
- first from nodes
- where dclass >= i and outgoing_connection
- order by dclass desc
- if disconnect
- goto disconnect
- else
- break
-
-
- // disconnect connections in case we have more than enough connections
-
- if max < cur
- delcon =
- first from nodes
- where outgoing_connection
- order by dclass desc
- goto disconnect
-
- // disconnect
-
-disconnect
- if delcon
- disconnect delcon
-
-
- // next iteration
- next (timeout, autoconnect)
-
-}
-
-*/
-
-
static void periodic_handler(event_loop_t *loop, void *data) {
meshlink_handle_t *mesh = loop->data;
/* Check if we need to make or break connections. */
if(mesh->nodes->count > 1) {
-
- logger(mesh, MESHLINK_DEBUG, "--- autoconnect begin ---");
-
- int retry_timeout = min(mesh->nodes->count * default_timeout, 60);
-
- logger(mesh, MESHLINK_DEBUG, "* devclass = %d", mesh->devclass);
- logger(mesh, MESHLINK_DEBUG, "* nodes = %d", mesh->nodes->count);
- logger(mesh, MESHLINK_DEBUG, "* retry_timeout = %d", retry_timeout);
-
-
- // connect disconnect nodes
-
- node_t *connect_to = NULL;
- node_t *disconnect_from = NULL;
-
-
- // get cur_connects
-
- unsigned int cur_connects = 0;
-
- for list_each(connection_t, c, mesh->connections) {
- if(c->status.active) {
- cur_connects += 1;
- }
- }
-
- logger(mesh, MESHLINK_DEBUG, "* cur_connects = %d", cur_connects);
- logger(mesh, MESHLINK_DEBUG, "* outgoings = %d", mesh->outgoings->count);
-
- // get min_connects and max_connects
-
- unsigned int min_connects = mesh->dev_class_traits[mesh->devclass].min_connects;
- unsigned int max_connects = mesh->dev_class_traits[mesh->devclass].max_connects;
-
- logger(mesh, MESHLINK_DEBUG, "* min_connects = %d", min_connects);
- logger(mesh, MESHLINK_DEBUG, "* max_connects = %d", max_connects);
-
- // find the best one for initial connect
-
- if(cur_connects < min_connects) {
- splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
-
- for splay_each(node_t, n, mesh->nodes) {
- logger(mesh, MESHLINK_DEBUG, "* %s->devclass = %d", n->name, n->devclass);
-
- if(n != mesh->self && n->devclass <= mesh->devclass && !n->connection && !n->status.blacklisted && (n->last_connect_try == 0 || (mesh->loop.now.tv_sec - n->last_connect_try) > retry_timeout)) {
- splay_insert(nodes, n);
- }
- }
-
- if(nodes->head) {
- //timeout = 0;
- connect_to = (node_t *)nodes->head->data;
-
- logger(mesh, MESHLINK_DEBUG, "* found best one for initial connect: %s", connect_to->name);
- } else {
- logger(mesh, MESHLINK_DEBUG, "* could not find node for initial connect");
- }
-
- splay_free_tree(nodes);
- }
-
-
- // find better nodes to connect to
-
- if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
- unsigned int connects = 0;
-
- for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
- for list_each(connection_t, c, mesh->connections) {
- if(c->status.active && c->node && c->node->devclass == devclass) {
- connects += 1;
- }
- }
-
- if(connects < min_connects) {
- splay_tree_t *nodes = splay_alloc_tree(node_compare_lsc_desc, NULL);
-
- for splay_each(node_t, n, mesh->nodes) {
- if(n != mesh->self && n->devclass == devclass && !n->connection && !n->status.blacklisted && (n->last_connect_try == 0 || (mesh->loop.now.tv_sec - n->last_connect_try) > retry_timeout)) {
- splay_insert(nodes, n);
- }
- }
-
- if(nodes->head) {
- logger(mesh, MESHLINK_DEBUG, "* found better node");
- connect_to = (node_t *)nodes->head->data;
-
- splay_free_tree(nodes);
- break;
- }
-
- splay_free_tree(nodes);
- } else {
- break;
- }
- }
-
- if(!connect_to) {
- logger(mesh, MESHLINK_DEBUG, "* could not find better nodes");
- }
- }
-
-
- // heal partitions
-
- if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
- splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
-
- for splay_each(node_t, n, mesh->nodes) {
- if(n != mesh->self && n->devclass <= mesh->devclass && !n->status.reachable && !n->status.blacklisted && (n->last_connect_try == 0 || (mesh->loop.now.tv_sec - n->last_connect_try) > retry_timeout)) {
- splay_insert(nodes, n);
- }
- }
-
- if(nodes->head) {
- logger(mesh, MESHLINK_DEBUG, "* try to heal partition");
- connect_to = (node_t *)nodes->head->data;
- } else {
- logger(mesh, MESHLINK_DEBUG, "* could not find nodes for partition healing");
- }
-
- splay_free_tree(nodes);
- }
-
-
- // perform connect
-
- if(connect_to && !connect_to->connection) {
- connect_to->last_connect_try = mesh->loop.now.tv_sec;
- logger(mesh, MESHLINK_DEBUG, "Autoconnect trying to connect to %s", connect_to->name);
-
- /* check if there is already a connection attempt to this node */
- bool skip = false;
-
- for list_each(outgoing_t, outgoing, mesh->outgoings) {
- if(outgoing->node == connect_to) {
- logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since it is an outgoing connection already");
- skip = true;
- break;
- }
- }
-
- if(!connect_to->status.reachable && !node_read_public_key(mesh, connect_to)) {
- logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since we don't know this node's public key");
- skip = true;
- }
-
- if(!skip) {
- logger(mesh, MESHLINK_DEBUG, "Autoconnecting to %s", connect_to->name);
- outgoing_t *outgoing = xzalloc(sizeof(outgoing_t));
- outgoing->node = connect_to;
- list_insert_tail(mesh->outgoings, outgoing);
- setup_outgoing_connection(mesh, outgoing);
- }
- }
-
-
- // disconnect suboptimal outgoing connections
-
- if(min_connects < cur_connects /*&& cur_connects <= max_connects*/) {
- unsigned int connects = 0;
-
- for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
- for list_each(connection_t, c, mesh->connections) {
- if(c->status.active && c->node && c->node->devclass == devclass) {
- connects += 1;
- }
- }
-
- if(min_connects < connects) {
- splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
-
- for list_each(connection_t, c, mesh->connections) {
- if(c->outgoing && c->node && c->node->devclass >= devclass) {
- splay_insert(nodes, c->node);
- }
- }
-
- if(nodes->head) {
- logger(mesh, MESHLINK_DEBUG, "* disconnect suboptimal outgoing connection");
- disconnect_from = (node_t *)nodes->head->data;
- }
-
- splay_free_tree(nodes);
- break;
- }
- }
-
- if(!disconnect_from) {
- logger(mesh, MESHLINK_DEBUG, "* no suboptimal outgoing connections");
- }
- }
-
-
- // disconnect connections (too many connections)
-
- if(!disconnect_from && max_connects < cur_connects) {
- splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
-
- for list_each(connection_t, c, mesh->connections) {
- if(c->status.active && c->node) {
- splay_insert(nodes, c->node);
- }
- }
-
- if(nodes->head) {
- logger(mesh, MESHLINK_DEBUG, "* disconnect connection (too many connections)");
-
- //timeout = 0;
- disconnect_from = (node_t *)nodes->head->data;
- } else {
- logger(mesh, MESHLINK_DEBUG, "* no node we want to disconnect, even though we have too many connections");
- }
-
- splay_free_tree(nodes);
- }
-
-
- // perform disconnect
-
- if(disconnect_from && disconnect_from->connection) {
- logger(mesh, MESHLINK_DEBUG, "Autodisconnecting from %s", disconnect_from->connection->name);
- list_delete(mesh->outgoings, disconnect_from->connection->outgoing);
- disconnect_from->connection->outgoing = NULL;
- terminate_connection(mesh, disconnect_from->connection, disconnect_from->connection->status.active);
- }
+ unsigned int cur_connects = do_autoconnect(mesh);
// reduce timeout if we don't have enough connections + outgoings
- if(cur_connects + mesh->outgoings->count < 3) {
+ if (cur_connects + mesh->outgoings->count < 3) {
timeout = 1;
}
-
- // done!
-
- logger(mesh, MESHLINK_DEBUG, "--- autoconnect end ---");
}
+ /* Write dirty config files out to disk */
+
for splay_each(node_t, n, mesh->nodes) {
if(n->status.dirty) {
node_write_config(mesh, n);
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