]> git.meshlink.io Git - meshlink/blob - src/net_socket.c
Simplify reading lines from configuration files.
[meshlink] / src / net_socket.c
1 /*
2     net_socket.c -- Handle various kinds of sockets.
3     Copyright (C) 1998-2005 Ivo Timmermans,
4                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
5                   2006      Scott Lamb <slamb@slamb.org>
6                   2009      Florian Forster <octo@verplant.org>
7
8     This program is free software; you can redistribute it and/or modify
9     it under the terms of the GNU General Public License as published by
10     the Free Software Foundation; either version 2 of the License, or
11     (at your option) any later version.
12
13     This program is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16     GNU General Public License for more details.
17
18     You should have received a copy of the GNU General Public License along
19     with this program; if not, write to the Free Software Foundation, Inc.,
20     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21 */
22
23 #include "system.h"
24
25 #include "avl_tree.h"
26 #include "conf.h"
27 #include "connection.h"
28 #include "event.h"
29 #include "logger.h"
30 #include "meta.h"
31 #include "net.h"
32 #include "netutl.h"
33 #include "protocol.h"
34 #include "utils.h"
35 #include "xalloc.h"
36
37 #include <assert.h>
38
39 /* Needed on Mac OS/X */
40 #ifndef SOL_TCP
41 #define SOL_TCP IPPROTO_TCP
42 #endif
43
44 int addressfamily = AF_UNSPEC;
45 int maxtimeout = 900;
46 int seconds_till_retry = 5;
47
48 listen_socket_t listen_socket[MAXSOCKETS];
49 int listen_sockets;
50 list_t *outgoing_list = NULL;
51
52 /* Setup sockets */
53
54 static void configure_tcp(connection_t *c) {
55         int option;
56
57 #ifdef O_NONBLOCK
58         int flags = fcntl(c->socket, F_GETFL);
59
60         if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0) {
61                 logger(LOG_ERR, "fcntl for %s: %s", c->hostname, strerror(errno));
62         }
63 #elif defined(WIN32)
64         unsigned long arg = 1;
65
66         if(ioctlsocket(c->socket, FIONBIO, &arg) != 0) {
67                 logger(LOG_ERR, "ioctlsocket for %s: %d", c->hostname, sockstrerror(sockerrno));
68         }
69 #endif
70
71 #if defined(SOL_TCP) && defined(TCP_NODELAY)
72         option = 1;
73         setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));
74 #endif
75
76 #if defined(SOL_IP) && defined(IP_TOS) && defined(IPTOS_LOWDELAY)
77         option = IPTOS_LOWDELAY;
78         setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
79 #endif
80 }
81
82 static bool bind_to_interface(int sd) {
83         char *iface;
84
85 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
86         struct ifreq ifr;
87         int status;
88 #endif /* defined(SOL_SOCKET) && defined(SO_BINDTODEVICE) */
89
90         if(!get_config_string (lookup_config (config_tree, "BindToInterface"), &iface))
91                 return true;
92
93 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
94         memset(&ifr, 0, sizeof(ifr));
95         strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
96         ifr.ifr_ifrn.ifrn_name[IFNAMSIZ - 1] = 0;
97
98         status = setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr));
99         if(status) {
100                 logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
101                                 strerror(errno));
102                 return false;
103         }
104 #else /* if !defined(SOL_SOCKET) || !defined(SO_BINDTODEVICE) */
105         logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
106 #endif
107
108         return true;
109 }
110
111 static bool bind_to_address(connection_t *c) {
112         char *node;
113         struct addrinfo *ai_list;
114         struct addrinfo *ai_ptr;
115         struct addrinfo ai_hints;
116         int status;
117
118         assert(c != NULL);
119         assert(c->socket >= 0);
120
121         node = NULL;
122         if(!get_config_string(lookup_config(config_tree, "BindToAddress"),
123                                 &node))
124                 return true;
125
126         assert(node != NULL);
127
128         memset(&ai_hints, 0, sizeof(ai_hints));
129         ai_hints.ai_family = c->address.sa.sa_family;
130         /* We're called from `do_outgoing_connection' only. */
131         ai_hints.ai_socktype = SOCK_STREAM;
132         ai_hints.ai_protocol = IPPROTO_TCP;
133
134         ai_list = NULL;
135
136         status = getaddrinfo(node, /* service = */ NULL,
137                         &ai_hints, &ai_list);
138         if(status) {
139                 free(node);
140                 logger(LOG_WARNING, "Error looking up %s port %s: %s",
141                                 node, "any", gai_strerror(status));
142                 return false;
143         }
144         assert(ai_list != NULL);
145
146         status = -1;
147         for(ai_ptr = ai_list; ai_ptr != NULL; ai_ptr = ai_ptr->ai_next) {
148                 status = bind(c->socket,
149                                 ai_list->ai_addr, ai_list->ai_addrlen);
150                 if(!status)
151                         break;
152         }
153
154
155         if(status) {
156                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", node, sockstrerror(sockerrno));
157         } else ifdebug(CONNECTIONS) {
158                 logger(LOG_DEBUG, "Successfully bound outgoing "
159                                 "TCP socket to %s", node);
160         }
161
162         free(node);
163         freeaddrinfo(ai_list);
164
165         return status ? false : true;
166 }
167
168 int setup_listen_socket(const sockaddr_t *sa) {
169         int nfd;
170         char *addrstr;
171         int option;
172         char *iface;
173
174         nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
175
176         if(nfd < 0) {
177                 ifdebug(STATUS) logger(LOG_ERR, "Creating metasocket failed: %s", sockstrerror(sockerrno));
178                 return -1;
179         }
180
181         /* Optimize TCP settings */
182
183         option = 1;
184         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
185
186 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
187         if(sa->sa.sa_family == AF_INET6)
188                 setsockopt(nfd, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
189 #endif
190
191         if(get_config_string
192            (lookup_config(config_tree, "BindToInterface"), &iface)) {
193 #if defined(SOL_SOCKET) && defined(SO_BINDTODEVICE)
194                 struct ifreq ifr;
195
196                 memset(&ifr, 0, sizeof(ifr));
197                 strncpy(ifr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
198
199                 if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, &ifr, sizeof(ifr))) {
200                         closesocket(nfd);
201                         logger(LOG_ERR, "Can't bind to interface %s: %s", iface,
202                                    strerror(sockerrno));
203                         return -1;
204                 }
205 #else
206                 logger(LOG_WARNING, "%s not supported on this platform", "BindToInterface");
207 #endif
208         }
209
210         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
211                 closesocket(nfd);
212                 addrstr = sockaddr2hostname(sa);
213                 logger(LOG_ERR, "Can't bind to %s/tcp: %s", addrstr, sockstrerror(sockerrno));
214                 free(addrstr);
215                 return -1;
216         }
217
218         if(listen(nfd, 3)) {
219                 closesocket(nfd);
220                 logger(LOG_ERR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
221                 return -1;
222         }
223
224         return nfd;
225 }
226
227 int setup_vpn_in_socket(const sockaddr_t *sa) {
228         int nfd;
229         char *addrstr;
230         int option;
231
232         nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
233
234         if(nfd < 0) {
235                 logger(LOG_ERR, "Creating UDP socket failed: %s", sockstrerror(sockerrno));
236                 return -1;
237         }
238
239 #ifdef O_NONBLOCK
240         {
241                 int flags = fcntl(nfd, F_GETFL);
242
243                 if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
244                         closesocket(nfd);
245                         logger(LOG_ERR, "System call `%s' failed: %s", "fcntl",
246                                    strerror(errno));
247                         return -1;
248                 }
249         }
250 #elif defined(WIN32)
251         {
252                 unsigned long arg = 1;
253                 if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
254                         closesocket(nfd);
255                         logger(LOG_ERR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
256                         return -1;
257                 }
258         }
259 #endif
260
261         option = 1;
262         setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
263
264 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
265         if(sa->sa.sa_family == AF_INET6)
266                 setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, &option, sizeof option);
267 #endif
268
269 #if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
270 #define IP_DONTFRAGMENT IP_DONTFRAG
271 #endif
272
273 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
274         if(myself->options & OPTION_PMTU_DISCOVERY) {
275                 option = IP_PMTUDISC_DO;
276                 setsockopt(nfd, SOL_IP, IP_MTU_DISCOVER, &option, sizeof(option));
277         }
278 #elif defined(IPPROTO_IP) && defined(IP_DONTFRAGMENT)
279         if(myself->options & OPTION_PMTU_DISCOVERY) {
280                 option = 1;
281                 setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, &option, sizeof(option));
282         }
283 #else
284 #warning No way to disable IPv4 fragmentation
285 #endif
286
287 #if defined(SOL_IPV6) && defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
288         if(myself->options & OPTION_PMTU_DISCOVERY) {
289                 option = IPV6_PMTUDISC_DO;
290                 setsockopt(nfd, SOL_IPV6, IPV6_MTU_DISCOVER, &option, sizeof(option));
291         }
292 #elif defined(IPPROTO_IPV6) && defined(IPV6_DONTFRAG)
293         if(myself->options & OPTION_PMTU_DISCOVERY) {
294                 option = 1;
295                 setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, &option, sizeof(option));
296         }
297 #else
298 #warning No way to disable IPv6 fragmentation
299 #endif
300
301         if (!bind_to_interface(nfd)) {
302                 closesocket(nfd);
303                 return -1;
304         }
305
306         if(bind(nfd, &sa->sa, SALEN(sa->sa))) {
307                 closesocket(nfd);
308                 addrstr = sockaddr2hostname(sa);
309                 logger(LOG_ERR, "Can't bind to %s/udp: %s", addrstr, sockstrerror(sockerrno));
310                 free(addrstr);
311                 return -1;
312         }
313
314         return nfd;
315 } /* int setup_vpn_in_socket */
316
317 void retry_outgoing(outgoing_t *outgoing) {
318         outgoing->timeout += 5;
319
320         if(outgoing->timeout > maxtimeout)
321                 outgoing->timeout = maxtimeout;
322
323         if(outgoing->event)
324                 event_del(outgoing->event);
325         outgoing->event = new_event();
326         outgoing->event->handler = (event_handler_t) setup_outgoing_connection;
327         outgoing->event->time = now + outgoing->timeout;
328         outgoing->event->data = outgoing;
329         event_add(outgoing->event);
330
331         ifdebug(CONNECTIONS) logger(LOG_NOTICE,
332                            "Trying to re-establish outgoing connection in %d seconds",
333                            outgoing->timeout);
334 }
335
336 void finish_connecting(connection_t *c) {
337         ifdebug(CONNECTIONS) logger(LOG_INFO, "Connected to %s (%s)", c->name, c->hostname);
338
339         configure_tcp(c);
340
341         c->last_ping_time = now;
342
343         send_id(c);
344 }
345
346 void do_outgoing_connection(connection_t *c) {
347         char *address, *port, *space;
348         int result;
349
350         if(!c->outgoing) {
351                 logger(LOG_ERR, "do_outgoing_connection() for %s called without c->outgoing", c->name);
352                 abort();
353         }
354
355 begin:
356         if(!c->outgoing->ai) {
357                 if(!c->outgoing->cfg) {
358                         ifdebug(CONNECTIONS) logger(LOG_ERR, "Could not set up a meta connection to %s",
359                                            c->name);
360                         c->status.remove = true;
361                         retry_outgoing(c->outgoing);
362                         c->outgoing = NULL;
363                         return;
364                 }
365
366                 get_config_string(c->outgoing->cfg, &address);
367
368                 space = strchr(address, ' ');
369                 if(space) {
370                         port = xstrdup(space + 1);
371                         *space = 0;
372                 } else {
373                         if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
374                                 port = xstrdup("655");
375                 }
376
377                 c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
378                 free(address);
379                 free(port);
380
381                 c->outgoing->aip = c->outgoing->ai;
382                 c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
383         }
384
385         if(!c->outgoing->aip) {
386                 if(c->outgoing->ai)
387                         freeaddrinfo(c->outgoing->ai);
388                 c->outgoing->ai = NULL;
389                 goto begin;
390         }
391
392         memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
393         c->outgoing->aip = c->outgoing->aip->ai_next;
394
395         if(c->hostname)
396                 free(c->hostname);
397
398         c->hostname = sockaddr2hostname(&c->address);
399
400         ifdebug(CONNECTIONS) logger(LOG_INFO, "Trying to connect to %s (%s)", c->name,
401                            c->hostname);
402
403         c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
404
405         if(c->socket == -1) {
406                 ifdebug(CONNECTIONS) logger(LOG_ERR, "Creating socket for %s failed: %s", c->hostname, sockstrerror(sockerrno));
407                 goto begin;
408         }
409
410 #if defined(SOL_IPV6) && defined(IPV6_V6ONLY)
411         int option = 1;
412         if(c->address.sa.sa_family == AF_INET6)
413                 setsockopt(c->socket, SOL_IPV6, IPV6_V6ONLY, &option, sizeof option);
414 #endif
415
416         bind_to_interface(c->socket);
417         bind_to_address(c);
418
419         /* Optimize TCP settings */
420
421         configure_tcp(c);
422
423         /* Connect */
424
425         result = connect(c->socket, &c->address.sa, SALEN(c->address.sa));
426
427         if(result == -1) {
428                 if(sockinprogress(sockerrno)) {
429                         c->status.connecting = true;
430                         return;
431                 }
432
433                 closesocket(c->socket);
434
435                 ifdebug(CONNECTIONS) logger(LOG_ERR, "%s: %s", c->hostname, sockstrerror(sockerrno));
436
437                 goto begin;
438         }
439
440         finish_connecting(c);
441
442         return;
443 }
444
445 void setup_outgoing_connection(outgoing_t *outgoing) {
446         connection_t *c;
447         node_t *n;
448
449         outgoing->event = NULL;
450
451         n = lookup_node(outgoing->name);
452
453         if(n)
454                 if(n->connection) {
455                         ifdebug(CONNECTIONS) logger(LOG_INFO, "Already connected to %s", outgoing->name);
456
457                         n->connection->outgoing = outgoing;
458                         return;
459                 }
460
461         c = new_connection();
462         c->name = xstrdup(outgoing->name);
463         c->outcipher = myself->connection->outcipher;
464         c->outdigest = myself->connection->outdigest;
465         c->outmaclength = myself->connection->outmaclength;
466         c->outcompression = myself->connection->outcompression;
467
468         init_configuration(&c->config_tree);
469         read_connection_config(c);
470
471         outgoing->cfg = lookup_config(c->config_tree, "Address");
472
473         if(!outgoing->cfg) {
474                 logger(LOG_ERR, "No address specified for %s", c->name);
475                 free_connection(c);
476                 return;
477         }
478
479         c->outgoing = outgoing;
480         c->last_ping_time = now;
481
482         connection_add(c);
483
484         do_outgoing_connection(c);
485 }
486
487 /*
488   accept a new tcp connect and create a
489   new connection
490 */
491 bool handle_new_meta_connection(int sock) {
492         connection_t *c;
493         sockaddr_t sa;
494         int fd;
495         socklen_t len = sizeof(sa);
496
497         fd = accept(sock, &sa.sa, &len);
498
499         if(fd < 0) {
500                 logger(LOG_ERR, "Accepting a new connection failed: %s", sockstrerror(sockerrno));
501                 return false;
502         }
503
504         sockaddrunmap(&sa);
505
506         c = new_connection();
507         c->name = xstrdup("<unknown>");
508         c->outcipher = myself->connection->outcipher;
509         c->outdigest = myself->connection->outdigest;
510         c->outmaclength = myself->connection->outmaclength;
511         c->outcompression = myself->connection->outcompression;
512
513         c->address = sa;
514         c->hostname = sockaddr2hostname(&sa);
515         c->socket = fd;
516         c->last_ping_time = now;
517
518         ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection from %s", c->hostname);
519
520         configure_tcp(c);
521
522         connection_add(c);
523
524         c->allow_request = ID;
525         send_id(c);
526
527         return true;
528 }
529
530 void free_outgoing(outgoing_t *outgoing) {
531         if(outgoing->ai)
532                 freeaddrinfo(outgoing->ai);
533
534         if(outgoing->name)
535                 free(outgoing->name);
536
537         free(outgoing);
538 }
539
540 void try_outgoing_connections(void) {
541         static config_t *cfg = NULL;
542         char *name;
543         outgoing_t *outgoing;
544         
545         outgoing_list = list_alloc((list_action_t)free_outgoing);
546                         
547         for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg)) {
548                 get_config_string(cfg, &name);
549
550                 if(!check_id(name)) {
551                         logger(LOG_ERR,
552                                    "Invalid name for outgoing connection in %s line %d",
553                                    cfg->file, cfg->line);
554                         free(name);
555                         continue;
556                 }
557
558                 outgoing = xmalloc_and_zero(sizeof(*outgoing));
559                 outgoing->name = name;
560                 list_insert_tail(outgoing_list, outgoing);
561                 setup_outgoing_connection(outgoing);
562         }
563 }