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Enforce spaces around operators.
[meshlink] / src / net.c
1 /*
2     net.c -- most of the network code
3     Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
4
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.
9
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.
14
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.
18 */
19
20 #include "system.h"
21
22 #include "utils.h"
23 #include "conf.h"
24 #include "connection.h"
25 #include "graph.h"
26 #include "logger.h"
27 #include "meshlink_internal.h"
28 #include "meta.h"
29 #include "net.h"
30 #include "netutl.h"
31 #include "protocol.h"
32 #include "xalloc.h"
33
34 #include <assert.h>
35
36 #if !defined(min)
37 static const int min(int a, int b) {
38         return a < b ? a : b;
39 }
40 #endif
41
42 /*
43   Terminate a connection:
44   - Mark it as inactive
45   - Remove the edge representing this connection
46   - Kill it with fire
47   - Check if we need to retry making an outgoing connection
48 */
49 void terminate_connection(meshlink_handle_t *mesh, connection_t *c, bool report) {
50         logger(mesh, MESHLINK_INFO, "Closing connection with %s (%s)", c->name, c->hostname);
51
52         c->status.active = false;
53
54         if(c->node && c->node->connection == c)
55                 c->node->connection = NULL;
56
57         if(c->edge) {
58                 if(report)
59                         send_del_edge(mesh, mesh->everyone, c->edge);
60
61                 edge_del(mesh, c->edge);
62                 c->edge = NULL;
63
64                 /* Run MST and SSSP algorithms */
65
66                 graph(mesh);
67
68                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
69
70                 if(report && !c->node->status.reachable) {
71                         edge_t *e;
72                         e = lookup_edge(c->node, mesh->self);
73                         if(e) {
74                                 send_del_edge(mesh, mesh->everyone, e);
75                                 edge_del(mesh, e);
76                         }
77                 }
78         }
79
80         outgoing_t *outgoing = c->outgoing;
81         connection_del(mesh, c);
82
83         /* Check if this was our outgoing connection */
84
85         if(outgoing)
86                 do_outgoing_connection(mesh, outgoing);
87
88 #ifndef HAVE_MINGW
89         /* Clean up dead proxy processes */
90
91         while(waitpid(-1, NULL, WNOHANG) > 0);
92 #endif
93 }
94
95 /*
96   Check if the other end is active.
97   If we have sent packets, but didn't receive any,
98   then possibly the other end is dead. We send a
99   PING request over the meta connection. If the other
100   end does not reply in time, we consider them dead
101   and close the connection.
102 */
103 static void timeout_handler(event_loop_t *loop, void *data) {
104         meshlink_handle_t *mesh = loop->data;
105         logger(mesh, MESHLINK_DEBUG, "timeout_handler()");
106
107         for list_each(connection_t, c, mesh->connections) {
108                 // Also make sure that if outstanding key requests for the UDP counterpart of a connection has timed out, we restart it.
109                 if(c->node) {
110                         if(c->node->status.waitingforkey && c->node->last_req_key + mesh->pingtimeout <= mesh->loop.now.tv_sec)
111                                 send_req_key(mesh, c->node);
112                 }
113                 if(c->last_ping_time + mesh->pingtimeout <= mesh->loop.now.tv_sec) {
114                         if(c->status.active) {
115                                 if(c->status.pinged)
116                                         logger(mesh, MESHLINK_INFO, "%s (%s) didn't respond to PING in %ld seconds", c->name, c->hostname, (long)mesh->loop.now.tv_sec - c->last_ping_time);
117                                 else if(c->last_ping_time + mesh->pinginterval <= mesh->loop.now.tv_sec) {
118                                         send_ping(mesh, c);
119                                         continue;
120                                 } else
121                                         continue;
122                         } else {
123                                 if(c->status.connecting)
124                                         logger(mesh, MESHLINK_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
125                                 else
126                                         logger(mesh, MESHLINK_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
127                         }
128                         terminate_connection(mesh, c, c->status.active);
129                 }
130         }
131
132         timeout_set(&mesh->loop, data, &(struct timeval) {
133                 mesh->pingtimeout, rand() % 100000
134         });
135 }
136
137 // devclass asc, last_successfull_connection desc
138 static int node_compare_devclass_asc_lsc_desc(const void *a, const void *b) {
139         const node_t *na = a, *nb = b;
140
141         if(na->devclass < nb->devclass)
142                 return -1;
143
144         if(na->devclass > nb->devclass)
145                 return 1;
146
147         if(na->last_successfull_connection == nb->last_successfull_connection)
148                 return 0;
149
150         if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection)
151                 return -1;
152
153         if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection)
154                 return 1;
155
156         if(na < nb)
157                 return -1;
158
159         if(na > nb)
160                 return 1;
161
162         return 0;
163 }
164
165 // last_successfull_connection desc
166 static int node_compare_lsc_desc(const void *a, const void *b) {
167         const node_t *na = a, *nb = b;
168
169         if(na->last_successfull_connection == nb->last_successfull_connection)
170                 return 0;
171
172         if(na->last_successfull_connection == 0 || na->last_successfull_connection > nb->last_successfull_connection)
173                 return -1;
174
175         if(nb->last_successfull_connection == 0 || na->last_successfull_connection < nb->last_successfull_connection)
176                 return 1;
177
178         if(na < nb)
179                 return -1;
180
181         if(na > nb)
182                 return 1;
183
184         return 0;
185 }
186
187 // devclass desc
188 static int node_compare_devclass_desc(const void *a, const void *b) {
189         const node_t *na = a, *nb = b;
190
191         if(na->devclass < nb->devclass)
192                 return -1;
193
194         if(na->devclass > nb->devclass)
195                 return 1;
196
197         if(na < nb)
198                 return -1;
199
200         if(na > nb)
201                 return 1;
202
203         return 0;
204 }
205
206
207 /*
208
209 autoconnect()
210 {
211         timeout = 5
212
213         // find the best one for initial connect
214
215         if cur < min
216                 newcon =
217                         first from nodes
218                                 where dclass <= my.dclass and !connection and (timestamp - last_retry) > retry_timeout
219                                 order by dclass asc, last_connection desc
220                 if newcon
221                         timeout = 0
222                         goto connect
223
224
225         // 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
226
227         if min <= cur < max
228                 j = 0
229                 for i = BACKBONE to my.dclass
230                         j += count(from connections where node.dclass = i)
231                         if j < min
232                                 newcon =
233                                         first from nodes
234                                                 where dclass = i and !connection and (timestamp - last_retry) > retry_timeout
235                                                 order by last_connection desc
236                                 if newcon
237                                         goto connect
238                         else
239                                 break
240
241
242         // heal partitions
243
244         if min <= cur < max
245                 newcon =
246                         first from nodes
247                                 where dclass <= my.dclass and !reachable and (timestamp - last_retry) > retry_timeout
248                                 order by dclass asc, last_connection desc
249                 if newcon
250                         goto connect
251
252
253         // connect
254
255 connect:
256         if newcon
257                 connect newcon
258
259
260         // 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]
261
262         if min < cur <= max
263                 j = 0
264                 for i = BACKBONE to my.dclass
265                         j += count(from connections where node.dclass = i)
266                         if min < j
267                                 delcon =
268                                         first from nodes
269                                                 where dclass >= i and outgoing_connection
270                                                 order by dclass desc
271                                 if disconnect
272                                         goto disconnect
273                                 else
274                                         break
275
276
277         // disconnect connections in case we have more than enough connections
278
279         if max < cur
280                 delcon =
281                         first from nodes
282                                 where outgoing_connection
283                                 order by dclass desc
284                 goto disconnect
285
286         // disconnect
287
288 disconnect
289         if delcon
290                 disconnect delcon
291
292
293         // next iteration
294         next (timeout, autoconnect)
295
296 }
297
298 */
299
300
301 static void periodic_handler(event_loop_t *loop, void *data) {
302         meshlink_handle_t *mesh = loop->data;
303
304         /* Check if there are too many contradicting ADD_EDGE and DEL_EDGE messages.
305            This usually only happens when another node has the same Name as this node.
306            If so, sleep for a short while to prevent a storm of contradicting messages.
307         */
308
309         if(mesh->contradicting_del_edge > 100 && mesh->contradicting_add_edge > 100) {
310                 logger(mesh, MESHLINK_WARNING, "Possible node with same Name as us! Sleeping %d seconds.", mesh->sleeptime);
311                 usleep(mesh->sleeptime * 1000000LL);
312                 mesh->sleeptime *= 2;
313                 if(mesh->sleeptime < 0)
314                         mesh->sleeptime = 3600;
315         } else {
316                 mesh->sleeptime /= 2;
317                 if(mesh->sleeptime < 10)
318                         mesh->sleeptime = 10;
319         }
320
321         mesh->contradicting_add_edge = 0;
322         mesh->contradicting_del_edge = 0;
323
324         int timeout = 5;
325
326         /* Check if we need to make or break connections. */
327
328         if(mesh->nodes->count > 1) {
329
330                 logger(mesh, MESHLINK_DEBUG, "--- autoconnect begin ---");
331
332                 int retry_timeout = min(mesh->nodes->count * 5, 60);
333
334                 logger(mesh, MESHLINK_DEBUG, "* devclass = %d", mesh->devclass);
335                 logger(mesh, MESHLINK_DEBUG, "* nodes = %d", mesh->nodes->count);
336                 logger(mesh, MESHLINK_DEBUG, "* retry_timeout = %d", retry_timeout);
337
338
339                 // connect disconnect nodes
340
341                 node_t *connect_to = NULL;
342                 node_t *disconnect_from = NULL;
343
344
345                 // get cur_connects
346
347                 int cur_connects = 0;
348
349                 for list_each(connection_t, c, mesh->connections) {
350                         if(c->status.active)
351                                 cur_connects += 1;
352                 }
353
354                 logger(mesh, MESHLINK_DEBUG, "* cur_connects = %d", cur_connects);
355                 logger(mesh, MESHLINK_DEBUG, "* outgoings = %d", mesh->outgoings->count);
356
357                 // get min_connects and max_connects
358
359                 assert(mesh->devclass >= 0 && mesh->devclass <= _DEV_CLASS_MAX);
360
361                 int min_connects = dev_class_traits[mesh->devclass].min_connects;
362                 int max_connects = dev_class_traits[mesh->devclass].max_connects;
363
364                 logger(mesh, MESHLINK_DEBUG, "* min_connects = %d", min_connects);
365                 logger(mesh, MESHLINK_DEBUG, "* max_connects = %d", max_connects);
366
367
368                 // find the best one for initial connect
369
370                 if(cur_connects < min_connects) {
371                         splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
372
373                         for splay_each(node_t, n, mesh->nodes) {
374                                 logger(mesh, MESHLINK_DEBUG, "* n->devclass = %d", n->devclass);
375                                 if(n != mesh->self && n->devclass <= mesh->devclass && !n->connection && (n->last_connect_try == 0 || (time(NULL) - n->last_connect_try) > retry_timeout))
376                                         splay_insert(nodes, n);
377                         }
378
379                         if(nodes->head) {
380                                 logger(mesh, MESHLINK_DEBUG, "* found best one for initial connect");
381
382                                 //timeout = 0;
383                                 connect_to = (node_t *)nodes->head->data;
384                         } else
385                                 logger(mesh, MESHLINK_DEBUG, "* could not find node for initial connect");
386
387                         splay_free_tree(nodes);
388                 }
389
390
391                 // find better nodes to connect to
392
393                 if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
394                         unsigned int connects = 0;
395
396                         for(int devclass = 0; devclass <= mesh->devclass; ++devclass) {
397                                 for list_each(connection_t, c, mesh->connections) {
398                                         if(c->status.active && c->node && c->node->devclass == devclass)
399                                                 connects += 1;
400                                 }
401
402                                 if(connects < min_connects) {
403                                         splay_tree_t *nodes = splay_alloc_tree(node_compare_lsc_desc, NULL);
404
405                                         for splay_each(node_t, n, mesh->nodes) {
406                                                 if(n != mesh->self && n->devclass == devclass && !n->connection && (n->last_connect_try == 0 || (time(NULL) - n->last_connect_try) > retry_timeout))
407                                                         splay_insert(nodes, n);
408                                         }
409
410                                         if(nodes->head) {
411                                                 logger(mesh, MESHLINK_DEBUG, "* found better node");
412                                                 connect_to = (node_t *)nodes->head->data;
413
414                                                 splay_free_tree(nodes);
415                                                 break;
416                                         }
417
418                                         splay_free_tree(nodes);
419                                 } else
420                                         break;
421                         }
422
423                         if(!connect_to)
424                                 logger(mesh, MESHLINK_DEBUG, "* could not find better nodes");
425                 }
426
427
428                 // heal partitions
429
430                 if(!connect_to && min_connects <= cur_connects && cur_connects < max_connects) {
431                         splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_asc_lsc_desc, NULL);
432
433                         for splay_each(node_t, n, mesh->nodes) {
434                                 if(n != mesh->self && n->devclass <= mesh->devclass && !n->status.reachable && (n->last_connect_try == 0 || (time(NULL) - n->last_connect_try) > retry_timeout))
435                                         splay_insert(nodes, n);
436                         }
437
438                         if(nodes->head) {
439                                 logger(mesh, MESHLINK_DEBUG, "* try to heal partition");
440                                 connect_to = (node_t *)nodes->head->data;
441                         } else
442                                 logger(mesh, MESHLINK_DEBUG, "* could not find nodes for partition healing");
443
444                         splay_free_tree(nodes);
445                 }
446
447
448                 // perform connect
449
450                 if(connect_to && !connect_to->connection) {
451                         connect_to->last_connect_try = time(NULL);
452
453                         /* check if there is already a connection attempt to this node */
454                         bool found = false;
455                         for list_each(outgoing_t, outgoing, mesh->outgoings) {
456                                 if(!strcmp(outgoing->name, connect_to->name)) {
457                                         found = true;
458                                         break;
459                                 }
460                         }
461
462                         if(!found) {
463                                 logger(mesh, MESHLINK_DEBUG, "Autoconnecting to %s", connect_to->name);
464                                 outgoing_t *outgoing = xzalloc(sizeof(outgoing_t));
465                                 outgoing->mesh = mesh;
466                                 outgoing->name = xstrdup(connect_to->name);
467                                 list_insert_tail(mesh->outgoings, outgoing);
468                                 setup_outgoing_connection(mesh, outgoing);
469                         } else
470                                 logger(mesh, MESHLINK_DEBUG, "* skip autoconnect since it is an outgoing connection already");
471                 }
472
473
474                 // disconnect suboptimal outgoing connections
475
476                 if(min_connects < cur_connects /*&& cur_connects <= max_connects*/) {
477                         unsigned int connects = 0;
478
479                         for(int devclass = 0; devclass <= mesh->devclass; ++devclass) {
480                                 for list_each(connection_t, c, mesh->connections) {
481                                         if(c->status.active && c->node && c->node->devclass == devclass)
482                                                 connects += 1;
483                                 }
484
485                                 if(min_connects < connects) {
486                                         splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
487
488                                         for list_each(connection_t, c, mesh->connections) {
489                                                 if(c->outgoing && c->node && c->node->devclass >= devclass)
490                                                         splay_insert(nodes, c->node);
491                                         }
492
493                                         if(nodes->head) {
494                                                 logger(mesh, MESHLINK_DEBUG, "* disconnect suboptimal outgoing connection");
495                                                 disconnect_from = (node_t *)nodes->head->data;
496                                         }
497
498                                         splay_free_tree(nodes);
499                                         break;
500                                 }
501                         }
502
503                         if(!disconnect_from)
504                                 logger(mesh, MESHLINK_DEBUG, "* no suboptimal outgoing connections");
505                 }
506
507
508                 // disconnect connections (too many connections)
509
510                 if(!disconnect_from && max_connects < cur_connects) {
511                         splay_tree_t *nodes = splay_alloc_tree(node_compare_devclass_desc, NULL);
512
513                         for list_each(connection_t, c, mesh->connections) {
514                                 if(c->status.active && c->node)
515                                         splay_insert(nodes, c->node);
516                         }
517
518                         if(nodes->head) {
519                                 logger(mesh, MESHLINK_DEBUG, "* disconnect connection (too many connections)");
520
521                                 //timeout = 0;
522                                 disconnect_from = (node_t *)nodes->head->data;
523                         } else
524                                 logger(mesh, MESHLINK_DEBUG, "* no node we want to disconnect, even though we have too many connections");
525
526                         splay_free_tree(nodes);
527                 }
528
529
530                 // perform disconnect
531
532                 if(disconnect_from && disconnect_from->connection) {
533                         logger(mesh, MESHLINK_DEBUG, "Autodisconnecting from %s", disconnect_from->connection->name);
534                         list_delete(mesh->outgoings, disconnect_from->connection->outgoing);
535                         disconnect_from->connection->outgoing = NULL;
536                         terminate_connection(mesh, disconnect_from->connection, disconnect_from->connection->status.active);
537                 }
538
539
540                 // done!
541
542                 logger(mesh, MESHLINK_DEBUG, "--- autoconnect end ---");
543         }
544
545         timeout_set(&mesh->loop, data, &(struct timeval) {
546                 timeout, rand() % 100000
547         });
548 }
549
550 void handle_meta_connection_data(meshlink_handle_t *mesh, connection_t *c) {
551         if(!receive_meta(mesh, c)) {
552                 terminate_connection(mesh, c, c->status.active);
553                 return;
554         }
555 }
556
557 void retry(meshlink_handle_t *mesh) {
558         /* Reset the reconnection timers for all outgoing connections */
559         for list_each(outgoing_t, outgoing, mesh->outgoings) {
560                 outgoing->timeout = 0;
561                 if(outgoing->ev.cb)
562                         timeout_set(&mesh->loop, &outgoing->ev, &(struct timeval) {
563                         0, 0
564                 });
565         }
566
567         /* Check for outgoing connections that are in progress, and reset their ping timers */
568         for list_each(connection_t, c, mesh->connections) {
569                 if(c->outgoing && !c->node)
570                         c->last_ping_time = 0;
571         }
572
573         /* Kick the ping timeout handler */
574         timeout_set(&mesh->loop, &mesh->pingtimer, &(struct timeval) {
575                 0, 0
576         });
577 }
578
579 /*
580   this is where it all happens...
581 */
582 int main_loop(meshlink_handle_t *mesh) {
583         timeout_add(&mesh->loop, &mesh->pingtimer, timeout_handler, &mesh->pingtimer, &(struct timeval) {
584                 mesh->pingtimeout, rand() % 100000
585         });
586         timeout_add(&mesh->loop, &mesh->periodictimer, periodic_handler, &mesh->periodictimer, &(struct timeval) {
587                 0, 0
588         });
589
590         //Add signal handler
591         mesh->datafromapp.signum = 0;
592         signal_add(&(mesh->loop), &(mesh->datafromapp), (signal_cb_t)meshlink_send_from_queue, mesh, mesh->datafromapp.signum);
593
594         if(!event_loop_run(&(mesh->loop), &(mesh->mesh_mutex))) {
595                 logger(mesh, MESHLINK_ERROR, "Error while waiting for input: %s", strerror(errno));
596                 return 1;
597         }
598
599         timeout_del(&mesh->loop, &mesh->periodictimer);
600         timeout_del(&mesh->loop, &mesh->pingtimer);
601
602         return 0;
603 }