2 net.c -- most of the network code
3 Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24 #include "connection.h"
27 #include "meshlink_internal.h"
37 static inline int min(int a, int b) {
42 static const int default_timeout = 5;
43 static const int default_interval = 60;
46 Terminate a connection:
48 - Remove the edge representing this connection
50 - Check if we need to retry making an outgoing connection
52 void terminate_connection(meshlink_handle_t *mesh, connection_t *c, bool report) {
53 logger(mesh, MESHLINK_INFO, "Closing connection with %s", c->name);
55 c->status.active = false;
57 if(c->node && c->node->connection == c) {
58 c->node->connection = NULL;
63 send_del_edge(mesh, mesh->everyone, c->edge, 0);
66 edge_del(mesh, c->edge);
69 /* Run MST and SSSP algorithms */
73 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
75 if(report && c->node && !c->node->status.reachable) {
77 e = lookup_edge(c->node, mesh->self);
80 send_del_edge(mesh, mesh->everyone, e, 0);
86 outgoing_t *outgoing = c->outgoing;
87 connection_del(mesh, c);
89 /* Check if this was our outgoing connection */
92 do_outgoing_connection(mesh, outgoing);
96 /* Clean up dead proxy processes */
98 while(waitpid(-1, NULL, WNOHANG) > 0);
104 Check if the other end is active.
105 If we have sent packets, but didn't receive any,
106 then possibly the other end is dead. We send a
107 PING request over the meta connection. If the other
108 end does not reply in time, we consider them dead
109 and close the connection.
111 static void timeout_handler(event_loop_t *loop, void *data) {
114 meshlink_handle_t *mesh = loop->data;
115 logger(mesh, MESHLINK_DEBUG, "timeout_handler()");
117 for list_each(connection_t, c, mesh->connections) {
118 int pingtimeout = c->node ? mesh->dev_class_traits[c->node->devclass].pingtimeout : default_timeout;
119 int pinginterval = c->node ? mesh->dev_class_traits[c->node->devclass].pinginterval : default_interval;
121 // Also make sure that if outstanding key requests for the UDP counterpart of a connection has timed out, we restart it.
123 if(c->node->status.waitingforkey && c->node->last_req_key + pingtimeout <= mesh->loop.now.tv_sec) {
124 send_req_key(mesh, c->node);
128 if(c->last_ping_time + pingtimeout <= mesh->loop.now.tv_sec) {
129 if(c->status.active) {
130 if(c->status.pinged) {
131 logger(mesh, MESHLINK_INFO, "%s didn't respond to PING in %ld seconds", c->name, (long)mesh->loop.now.tv_sec - c->last_ping_time);
132 } else if(c->last_ping_time + pinginterval <= mesh->loop.now.tv_sec) {
139 if(c->status.connecting) {
140 logger(mesh, MESHLINK_WARNING, "Timeout while connecting to %s", c->name);
142 logger(mesh, MESHLINK_WARNING, "Timeout from %s during authentication", c->name);
146 terminate_connection(mesh, c, c->status.active);
150 timeout_set(&mesh->loop, data, &(struct timeval) {
151 default_timeout, prng(mesh, TIMER_FUDGE)
155 // devclass asc, last_successfull_connection desc
156 static int node_compare_devclass_asc_lsc_desc(const void *a, const void *b) {
157 const node_t *na = a, *nb = b;
159 if(na->devclass < nb->devclass) {
163 if(na->devclass > nb->devclass) {
167 if(na->last_successfull_connection == nb->last_successfull_connection) {
171 if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection) {
175 if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection) {
190 // last_successfull_connection desc
191 static int node_compare_lsc_desc(const void *a, const void *b) {
192 const node_t *na = a, *nb = b;
194 if(na->last_successfull_connection == nb->last_successfull_connection) {
198 if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection) {
202 if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection) {
218 static int node_compare_devclass_desc(const void *a, const void *b) {
219 const node_t *na = a, *nb = b;
221 if(na->devclass < nb->devclass) {
225 if(na->devclass > nb->devclass) {
247 // find the best one for initial connect
252 where dclass <= my.dclass and !connection and (timestamp - last_retry) > retry_timeout
253 order by dclass asc, last_connection desc
259 // 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
263 for i = BACKBONE to my.dclass
264 j += count(from connections where node.dclass = i)
268 where dclass = i and !connection and (timestamp - last_retry) > retry_timeout
269 order by last_connection desc
281 where dclass <= my.dclass and !reachable and (timestamp - last_retry) > retry_timeout
282 order by dclass asc, last_connection desc
294 // 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]
298 for i = BACKBONE to my.dclass
299 j += count(from connections where node.dclass = i)
303 where dclass >= i and outgoing_connection
311 // disconnect connections in case we have more than enough connections
316 where outgoing_connection
328 next (timeout, autoconnect)
335 static void periodic_handler(event_loop_t *loop, void *data) {
336 meshlink_handle_t *mesh = loop->data;
338 /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
339 This usually only happens when another node has the same Name as this node.
340 If so, sleep for a short while to prevent a storm of contradicting messages.
343 if(mesh->contradicting_del_edge > 100 && mesh->contradicting_add_edge > 100) {
344 logger(mesh, MESHLINK_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", mesh->sleeptime);
345 usleep(mesh->sleeptime * 1000000LL);
346 mesh->sleeptime *= 2;
348 if(mesh->sleeptime < 0) {
349 mesh->sleeptime = 3600;
352 mesh->sleeptime /= 2;
354 if(mesh->sleeptime < 10) {
355 mesh->sleeptime = 10;
359 mesh->contradicting_add_edge = 0;
360 mesh->contradicting_del_edge = 0;
362 int timeout = default_timeout;
364 /* Check if we need to make or break connections. */
366 if(mesh->nodes->count > 1) {
368 logger(mesh, MESHLINK_DEBUG, "--- autoconnect begin ---");
370 int retry_timeout = min(mesh->nodes->count * default_timeout, 60);
372 logger(mesh, MESHLINK_DEBUG, "* devclass = %d", mesh->devclass);
373 logger(mesh, MESHLINK_DEBUG, "* nodes = %d", mesh->nodes->count);
374 logger(mesh, MESHLINK_DEBUG, "* retry_timeout = %d", retry_timeout);
377 // connect disconnect nodes
379 node_t *connect_to = NULL;
380 node_t *disconnect_from = NULL;
385 unsigned int cur_connects = 0;
387 for list_each(connection_t, c, mesh->connections) {
388 if(c->status.active) {
393 logger(mesh, MESHLINK_DEBUG, "* cur_connects = %d", cur_connects);
394 logger(mesh, MESHLINK_DEBUG, "* outgoings = %d", mesh->outgoings->count);
396 // get min_connects and max_connects
398 unsigned int min_connects = mesh->dev_class_traits[mesh->devclass].min_connects;
399 unsigned int max_connects = mesh->dev_class_traits[mesh->devclass].max_connects;
401 logger(mesh, MESHLINK_DEBUG, "* min_connects = %d", min_connects);
402 logger(mesh, MESHLINK_DEBUG, "* max_connects = %d", max_connects);
404 // find the best one for initial connect
406 if(cur_connects < min_connects) {
407 splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
409 for splay_each(node_t, n, mesh->nodes) {
410 logger(mesh, MESHLINK_DEBUG, "* %s->devclass = %d", n->name, n->devclass);
412 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)) {
413 splay_insert(nodes, n);
419 connect_to = (node_t *)nodes->head->data;
421 logger(mesh, MESHLINK_DEBUG, "* found best one for initial connect: %s", connect_to->name);
423 logger(mesh, MESHLINK_DEBUG, "* could not find node for initial connect");
426 splay_delete_tree(nodes);
430 // find better nodes to connect to
432 if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
433 unsigned int connects = 0;
435 for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
436 for list_each(connection_t, c, mesh->connections) {
437 if(c->status.active && c->node && c->node->devclass == devclass) {
442 if(connects < min_connects) {
443 splay_tree_t *nodes = splay_alloc_tree(node_compare_lsc_desc, NULL);
445 for splay_each(node_t, n, mesh->nodes) {
446 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)) {
447 splay_insert(nodes, n);
452 logger(mesh, MESHLINK_DEBUG, "* found better node");
453 connect_to = (node_t *)nodes->head->data;
455 splay_delete_tree(nodes);
459 splay_delete_tree(nodes);
466 logger(mesh, MESHLINK_DEBUG, "* could not find better nodes");
473 if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
474 splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
476 for splay_each(node_t, n, mesh->nodes) {
477 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)) {
478 splay_insert(nodes, n);
483 logger(mesh, MESHLINK_DEBUG, "* try to heal partition");
484 connect_to = (node_t *)nodes->head->data;
486 logger(mesh, MESHLINK_DEBUG, "* could not find nodes for partition healing");
489 splay_delete_tree(nodes);
495 if(connect_to && !connect_to->connection) {
496 connect_to->last_connect_try = mesh->loop.now.tv_sec;
497 logger(mesh, MESHLINK_DEBUG, "Autoconnect trying to connect to %s", connect_to->name);
499 /* check if there is already a connection attempt to this node */
502 for list_each(outgoing_t, outgoing, mesh->outgoings) {
503 if(outgoing->node == connect_to) {
504 logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since it is an outgoing connection already");
510 if(!connect_to->status.reachable && !node_read_public_key(mesh, connect_to)) {
511 logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since we don't know this node's public key");
516 logger(mesh, MESHLINK_DEBUG, "Autoconnecting to %s", connect_to->name);
517 outgoing_t *outgoing = xzalloc(sizeof(outgoing_t));
518 outgoing->node = connect_to;
519 list_insert_tail(mesh->outgoings, outgoing);
520 setup_outgoing_connection(mesh, outgoing);
525 // disconnect suboptimal outgoing connections
527 if(min_connects < cur_connects /*&& cur_connects <= max_connects*/) {
528 unsigned int connects = 0;
530 for(dev_class_t devclass = 0; devclass <= mesh->devclass; ++devclass) {
531 for list_each(connection_t, c, mesh->connections) {
532 if(c->status.active && c->node && c->node->devclass == devclass) {
537 if(min_connects < connects) {
538 splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
540 for list_each(connection_t, c, mesh->connections) {
541 if(c->outgoing && c->node && c->node->devclass >= devclass) {
542 splay_insert(nodes, c->node);
547 logger(mesh, MESHLINK_DEBUG, "* disconnect suboptimal outgoing connection");
548 disconnect_from = (node_t *)nodes->head->data;
551 splay_delete_tree(nodes);
556 if(!disconnect_from) {
557 logger(mesh, MESHLINK_DEBUG, "* no suboptimal outgoing connections");
562 // disconnect connections (too many connections)
564 if(!disconnect_from && max_connects < cur_connects) {
565 splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
567 for list_each(connection_t, c, mesh->connections) {
568 if(c->status.active && c->node) {
569 splay_insert(nodes, c->node);
574 logger(mesh, MESHLINK_DEBUG, "* disconnect connection (too many connections)");
577 disconnect_from = (node_t *)nodes->head->data;
579 logger(mesh, MESHLINK_DEBUG, "* no node we want to disconnect, even though we have too many connections");
582 splay_delete_tree(nodes);
586 // perform disconnect
588 if(disconnect_from && disconnect_from->connection) {
589 logger(mesh, MESHLINK_DEBUG, "Autodisconnecting from %s", disconnect_from->connection->name);
590 list_delete(mesh->outgoings, disconnect_from->connection->outgoing);
591 disconnect_from->connection->outgoing = NULL;
592 terminate_connection(mesh, disconnect_from->connection, disconnect_from->connection->status.active);
595 // reduce timeout if we don't have enough connections + outgoings
596 if(cur_connects + mesh->outgoings->count < 3) {
602 logger(mesh, MESHLINK_DEBUG, "--- autoconnect end ---");
605 for splay_each(node_t, n, mesh->nodes) {
606 if(n->status.dirty) {
607 node_write_config(mesh, n);
608 n->status.dirty = false;
612 timeout_set(&mesh->loop, data, &(struct timeval) {
613 timeout, prng(mesh, TIMER_FUDGE)
617 void handle_meta_connection_data(meshlink_handle_t *mesh, connection_t *c) {
618 if(!receive_meta(mesh, c)) {
619 terminate_connection(mesh, c, c->status.active);
624 void retry(meshlink_handle_t *mesh) {
625 /* Reset the reconnection timers for all outgoing connections */
626 for list_each(outgoing_t, outgoing, mesh->outgoings) {
627 outgoing->timeout = 0;
630 timeout_set(&mesh->loop, &outgoing->ev, &(struct timeval) {
635 #ifdef HAVE_IFADDRS_H
636 struct ifaddrs *ifa = NULL;
640 /* For active connections, check if their addresses are still valid.
641 * If yes, reset their ping timers, otherwise terminate them. */
642 for list_each(connection_t, c, mesh->connections) {
643 if(!c->status.active) {
647 if(!c->status.pinged) {
648 c->last_ping_time = 0;
651 #ifdef HAVE_IFADDRS_H
658 socklen_t salen = sizeof(sa);
660 if(getsockname(c->socket, &sa.sa, &salen)) {
666 for(struct ifaddrs *ifap = ifa; ifap; ifap = ifap->ifa_next) {
667 if(ifap->ifa_addr && !sockaddrcmp_noport(&sa, (sockaddr_t *)ifap->ifa_addr)) {
675 logger(mesh, MESHLINK_DEBUG, "Local address for connection to %s no longer valid, terminating", c->name);
676 terminate_connection(mesh, c, c->status.active);
682 #ifdef HAVE_IFADDRS_H
690 /* Kick the ping timeout handler */
691 timeout_set(&mesh->loop, &mesh->pingtimer, &(struct timeval) {
697 this is where it all happens...
699 int main_loop(meshlink_handle_t *mesh) {
700 timeout_add(&mesh->loop, &mesh->pingtimer, timeout_handler, &mesh->pingtimer, &(struct timeval) {
701 default_timeout, prng(mesh, TIMER_FUDGE)
703 timeout_add(&mesh->loop, &mesh->periodictimer, periodic_handler, &mesh->periodictimer, &(struct timeval) {
708 mesh->datafromapp.signum = 0;
709 signal_add(&mesh->loop, &mesh->datafromapp, meshlink_send_from_queue, mesh, mesh->datafromapp.signum);
711 if(!event_loop_run(&mesh->loop, &mesh->mesh_mutex)) {
712 logger(mesh, MESHLINK_ERROR, "Error while waiting for input: %s", strerror(errno));
714 signal_del(&mesh->loop, &mesh->datafromapp);
715 timeout_del(&mesh->loop, &mesh->periodictimer);
716 timeout_del(&mesh->loop, &mesh->pingtimer);
721 signal_del(&mesh->loop, &mesh->datafromapp);
722 timeout_del(&mesh->loop, &mesh->periodictimer);
723 timeout_del(&mesh->loop, &mesh->pingtimer);