]> git.meshlink.io Git - meshlink/blob - src/net.c
Merge branch 'master' into 1.1
[meshlink] / src / net.c
1 /*
2     net.c -- most of the network code
3     Copyright (C) 1998-2005 Ivo Timmermans,
4                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
5                   2006      Scott Lamb <slamb@slamb.org>
6
7     This program is free software; you can redistribute it and/or modify
8     it under the terms of the GNU General Public License as published by
9     the Free Software Foundation; either version 2 of the License, or
10     (at your option) any later version.
11
12     This program is distributed in the hope that it will be useful,
13     but WITHOUT ANY WARRANTY; without even the implied warranty of
14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15     GNU General Public License for more details.
16
17     You should have received a copy of the GNU General Public License along
18     with this program; if not, write to the Free Software Foundation, Inc.,
19     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20 */
21
22 #include "system.h"
23
24 #include "utils.h"
25 #include "splay_tree.h"
26 #include "conf.h"
27 #include "connection.h"
28 #include "device.h"
29 #include "graph.h"
30 #include "logger.h"
31 #include "meta.h"
32 #include "net.h"
33 #include "netutl.h"
34 #include "process.h"
35 #include "protocol.h"
36 #include "subnet.h"
37 #include "xalloc.h"
38
39 int contradicting_add_edge = 0;
40 int contradicting_del_edge = 0;
41
42 /* Purge edges and subnets of unreachable nodes. Use carefully. */
43
44 void purge(void) {
45         splay_node_t *nnode, *nnext, *enode, *enext, *snode, *snext;
46         node_t *n;
47         edge_t *e;
48         subnet_t *s;
49
50         ifdebug(PROTOCOL) logger(LOG_DEBUG, "Purging unreachable nodes");
51
52         /* Remove all edges and subnets owned by unreachable nodes. */
53
54         for(nnode = node_tree->head; nnode; nnode = nnext) {
55                 nnext = nnode->next;
56                 n = nnode->data;
57
58                 if(!n->status.reachable) {
59                         ifdebug(SCARY_THINGS) logger(LOG_DEBUG, "Purging node %s (%s)", n->name,
60                                            n->hostname);
61
62                         for(snode = n->subnet_tree->head; snode; snode = snext) {
63                                 snext = snode->next;
64                                 s = snode->data;
65                                 send_del_subnet(broadcast, s);
66                                 if(!strictsubnets)
67                                         subnet_del(n, s);
68                         }
69
70                         for(enode = n->edge_tree->head; enode; enode = enext) {
71                                 enext = enode->next;
72                                 e = enode->data;
73                                 if(!tunnelserver)
74                                         send_del_edge(broadcast, e);
75                                 edge_del(e);
76                         }
77                 }
78         }
79
80         /* Check if anyone else claims to have an edge to an unreachable node. If not, delete node. */
81
82         for(nnode = node_tree->head; nnode; nnode = nnext) {
83                 nnext = nnode->next;
84                 n = nnode->data;
85
86                 if(!n->status.reachable) {
87                         for(enode = edge_weight_tree->head; enode; enode = enext) {
88                                 enext = enode->next;
89                                 e = enode->data;
90
91                                 if(e->to == n)
92                                         break;
93                         }
94
95                         if(!enode && (!strictsubnets || !n->subnet_tree->head))
96                                 /* in strictsubnets mode do not delete nodes with subnets */
97                                 node_del(n);
98                 }
99         }
100 }
101
102 /*
103   Terminate a connection:
104   - Close the socket
105   - Remove associated edge and tell other connections about it if report = true
106   - Check if we need to retry making an outgoing connection
107   - Deactivate the host
108 */
109 void terminate_connection(connection_t *c, bool report) {
110         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Closing connection with %s (%s)",
111                            c->name, c->hostname);
112
113         c->status.active = false;
114
115         if(c->node)
116                 c->node->connection = NULL;
117
118         if(c->socket)
119                 closesocket(c->socket);
120
121         if(c->edge) {
122                 if(report && !tunnelserver)
123                         send_del_edge(broadcast, c->edge);
124
125                 edge_del(c->edge);
126
127                 /* Run MST and SSSP algorithms */
128
129                 graph();
130
131                 /* If the node is not reachable anymore but we remember it had an edge to us, clean it up */
132
133                 if(report && !c->node->status.reachable) {
134                         edge_t *e;
135                         e = lookup_edge(c->node, myself);
136                         if(e) {
137                                 if(!tunnelserver)
138                                         send_del_edge(broadcast, e);
139                                 edge_del(e);
140                         }
141                 }
142         }
143
144         /* Check if this was our outgoing connection */
145
146         if(c->outgoing)
147                 retry_outgoing(c->outgoing);
148
149         connection_del(c);
150 }
151
152 /*
153   Check if the other end is active.
154   If we have sent packets, but didn't receive any,
155   then possibly the other end is dead. We send a
156   PING request over the meta connection. If the other
157   end does not reply in time, we consider them dead
158   and close the connection.
159 */
160 static void timeout_handler(int fd, short events, void *event) {
161         splay_node_t *node, *next;
162         connection_t *c;
163         time_t now = time(NULL);
164
165         for(node = connection_tree->head; node; node = next) {
166                 next = node->next;
167                 c = node->data;
168
169                 if(c->last_ping_time + pingtimeout < now) {
170                         if(c->status.active) {
171                                 if(c->status.pinged) {
172                                         ifdebug(CONNECTIONS) logger(LOG_INFO, "%s (%s) didn't respond to PING in %ld seconds",
173                                                            c->name, c->hostname, now - c->last_ping_time);
174                                         terminate_connection(c, true);
175                                         continue;
176                                 } else if(c->last_ping_time + pinginterval < now) {
177                                         send_ping(c);
178                                 }
179                         } else {
180                                 if(c->status.connecting) {
181                                         ifdebug(CONNECTIONS)
182                                                 logger(LOG_WARNING, "Timeout while connecting to %s (%s)", c->name, c->hostname);
183                                         c->status.connecting = false;
184                                         closesocket(c->socket);
185                                         do_outgoing_connection(c);
186                                 } else {
187                                         ifdebug(CONNECTIONS) logger(LOG_WARNING, "Timeout from %s (%s) during authentication", c->name, c->hostname);
188                                         terminate_connection(c, false);
189                                         continue;
190                                 }
191                         }
192                 }
193         }
194
195         if(contradicting_del_edge && contradicting_add_edge) {
196                 logger(LOG_WARNING, "Possible node with same Name as us!");
197
198                 if(rand() % 3 == 0) {
199                         logger(LOG_ERR, "Shutting down, check configuration of all nodes for duplicate Names!");
200                         event_loopexit(NULL);
201                         return;
202                 }
203
204                 contradicting_add_edge = 0;
205                 contradicting_del_edge = 0;
206         }
207
208         event_add(event, &(struct timeval){pingtimeout, 0});
209 }
210
211 void handle_meta_connection_data(int fd, short events, void *data) {
212         connection_t *c = data;
213         int result;
214         socklen_t len = sizeof result;
215
216         if(c->status.connecting) {
217                 c->status.connecting = false;
218
219                 getsockopt(c->socket, SOL_SOCKET, SO_ERROR, &result, &len);
220
221                 if(!result)
222                         finish_connecting(c);
223                 else {
224                         ifdebug(CONNECTIONS) logger(LOG_DEBUG,
225                                            "Error while connecting to %s (%s): %s",
226                                            c->name, c->hostname, sockstrerror(result));
227                         closesocket(c->socket);
228                         do_outgoing_connection(c);
229                         return;
230                 }
231         }
232
233         if (!receive_meta(c)) {
234                 terminate_connection(c, c->status.active);
235                 return;
236         }
237 }
238
239 static void sigterm_handler(int signal, short events, void *data) {
240         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
241         event_loopexit(NULL);
242 }
243
244 static void sighup_handler(int signal, short events, void *data) {
245         logger(LOG_NOTICE, "Got %s signal", strsignal(signal));
246         reload_configuration();
247 }
248
249 int reload_configuration(void) {
250         connection_t *c;
251         splay_node_t *node, *next;
252         char *fname;
253         struct stat s;
254         static time_t last_config_check = 0;
255
256         /* Reread our own configuration file */
257
258         exit_configuration(&config_tree);
259         init_configuration(&config_tree);
260
261         if(!read_server_config()) {
262                 logger(LOG_ERR, "Unable to reread configuration file, exitting.");
263                 event_loopexit(NULL);
264                 return EINVAL;
265         }
266
267         /* Close connections to hosts that have a changed or deleted host config file */
268         
269         for(node = connection_tree->head; node; node = next) {
270                 c = node->data;
271                 next = node->next;
272                 
273                 if(c->outgoing) {
274                         free(c->outgoing->name);
275                         if(c->outgoing->ai)
276                                 freeaddrinfo(c->outgoing->ai);
277                         free(c->outgoing);
278                         c->outgoing = NULL;
279                 }
280                 
281                 xasprintf(&fname, "%s/hosts/%s", confbase, c->name);
282                 if(stat(fname, &s) || s.st_mtime > last_config_check)
283                         terminate_connection(c, c->status.active);
284                 free(fname);
285         }
286
287         last_config_check = time(NULL);
288
289         /* If StrictSubnet is set, expire deleted Subnets and read new ones in */
290
291         if(strictsubnets) {
292                 subnet_t *subnet;
293
294
295                 for(node = subnet_tree->head; node; node = node->next) {
296                         subnet = node->data;
297                         subnet->expires = 1;
298                 }
299
300                 load_all_subnets();
301
302                 for(node = subnet_tree->head; node; node = next) {
303                         next = node->next;
304                         subnet = node->data;
305                         if(subnet->expires == 1) {
306                                 send_del_subnet(broadcast, subnet);
307                                 if(subnet->owner->status.reachable)
308                                         subnet_update(subnet->owner, subnet, false);
309                                 subnet_del(subnet->owner, subnet);
310                         } else if(subnet->expires == -1) {
311                                 subnet->expires = 0;
312                         } else {
313                                 send_add_subnet(broadcast, subnet);
314                                 if(subnet->owner->status.reachable)
315                                         subnet_update(subnet->owner, subnet, true);
316                         }
317                 }
318         }
319
320         /* Try to make outgoing connections */
321         
322         try_outgoing_connections();
323
324         return 0;
325 }
326
327 void retry(void) {
328         connection_t *c;
329         splay_node_t *node;
330
331         for(node = connection_tree->head; node; node = node->next) {
332                 c = node->data;
333                 
334                 if(c->outgoing && !c->node) {
335                         if(timeout_initialized(&c->outgoing->ev))
336                                 event_del(&c->outgoing->ev);
337                         if(c->status.connecting)
338                                 close(c->socket);
339                         c->outgoing->timeout = 0;
340                         do_outgoing_connection(c);
341                 }
342         }
343 }
344
345 /*
346   this is where it all happens...
347 */
348 int main_loop(void) {
349         struct event timeout_event;
350         struct event sighup_event;
351         struct event sigterm_event;
352         struct event sigquit_event;
353
354         timeout_set(&timeout_event, timeout_handler, &timeout_event);
355         event_add(&timeout_event, &(struct timeval){pingtimeout, 0});
356
357 #ifdef SIGHUP
358         signal_set(&sighup_event, SIGHUP, sighup_handler, NULL);
359         signal_add(&sighup_event, NULL);
360 #endif
361 #ifdef SIGTERM
362         signal_set(&sigterm_event, SIGTERM, sigterm_handler, NULL);
363         signal_add(&sigterm_event, NULL);
364 #endif
365 #ifdef SIGQUIT
366         signal_set(&sigquit_event, SIGQUIT, sigterm_handler, NULL);
367         signal_add(&sigquit_event, NULL);
368 #endif
369
370         if(event_loop(0) < 0) {
371                 logger(LOG_ERR, "Error while waiting for input: %s", strerror(errno));
372                 return 1;
373         }
374
375         signal_del(&sighup_event);
376         signal_del(&sigterm_event);
377         signal_del(&sigquit_event);
378         event_del(&timeout_event);
379
380         return 0;
381 }