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Revision: 1.15
Committed: Tue Oct 14 15:48:15 2003 UTC (20 years, 7 months ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.14: +2 -36 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 vpn.C -- handle the protocol, encryption, handshaking etc.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19 #include "config.h"
20
21 #include <list>
22
23 #include <cstdlib>
24 #include <cstring>
25 #include <cstdio>
26
27 #include <sys/types.h>
28 #include <sys/socket.h>
29 #include <sys/poll.h>
30 #include <sys/wait.h>
31 #include <errno.h>
32 #include <time.h>
33 #include <unistd.h>
34 #include <fcntl.h>
35 #include <sys/socket.h>
36
37 #include "netcompat.h"
38
39 #include "pidfile.h"
40
41 #include "connection.h"
42 #include "util.h"
43 #include "vpn.h"
44
45 /////////////////////////////////////////////////////////////////////////////
46
47 const char *vpn::script_if_up ()
48 {
49 // the tunnel device mtu should be the physical mtu - overhead
50 // the tricky part is rounding to the cipher key blocksize
51 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
52 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
53 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
54 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
55
56 char *env;
57 asprintf (&env, "CONFBASE=%s", confbase);
58 putenv (env);
59 asprintf (&env, "NODENAME=%s", THISNODE->nodename);
60 putenv (env);
61 asprintf (&env, "NODEID=%d", THISNODE->id);
62 putenv (env);
63 asprintf (&env, "IFNAME=%s", tap->interface ());
64 putenv (env);
65 asprintf (&env, "MTU=%d", mtu);
66 putenv (env);
67 asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
68 0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
69 THISNODE->id & 0xff);
70 putenv (env);
71
72 return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
73 }
74
75 int
76 vpn::setup ()
77 {
78 ipv4_fd = -1;
79
80 if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto)
81 {
82 ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
83
84 if (ipv4_fd < 0)
85 return -1;
86
87 fcntl (ipv4_fd, F_SETFL, O_NONBLOCK);
88
89 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
90 // this I really consider a linux bug. I am neither connected
91 // nor do I fragment myself. Linux still sets DF and doesn't
92 // fragment for me sometimes.
93 {
94 int oval = IP_PMTUDISC_DONT;
95 setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
96 }
97 #endif
98
99 sockinfo si (THISNODE, PROT_IPv4);
100
101 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
102 {
103 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
104 exit (1);
105 }
106
107 ipv4_ev_watcher.start (ipv4_fd, POLLIN);
108 }
109
110 udpv4_fd = -1;
111
112 if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
113 {
114 udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
115
116 if (udpv4_fd < 0)
117 return -1;
118
119 fcntl (udpv4_fd, F_SETFL, O_NONBLOCK);
120
121 // standard daemon practise...
122 {
123 int oval = 1;
124 setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
125 }
126
127 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
128 // this I really consider a linux bug. I am neither connected
129 // nor do I fragment myself. Linux still sets DF and doesn't
130 // fragment for me sometimes.
131 {
132 int oval = IP_PMTUDISC_DONT;
133 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
134 }
135 #endif
136
137 sockinfo si (THISNODE, PROT_UDPv4);
138
139 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
140 {
141 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
142 exit (1);
143 }
144
145 udpv4_ev_watcher.start (udpv4_fd, POLLIN);
146 }
147
148 icmpv4_fd = -1;
149
150 #if ENABLE_ICMP
151 if (THISNODE->protocols & PROT_ICMPv4)
152 {
153 icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP);
154
155 if (icmpv4_fd < 0)
156 return -1;
157
158 fcntl (icmpv4_fd, F_SETFL, O_NONBLOCK);
159
160 #ifdef ICMP_FILTER
161 {
162 icmp_filter oval;
163 oval.data = 0xffffffff;
164 if (::conf.icmp_type < 32)
165 oval.data &= ~(1 << ::conf.icmp_type);
166
167 setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval);
168 }
169 #endif
170
171 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
172 // this I really consider a linux bug. I am neither connected
173 // nor do I fragment myself. Linux still sets DF and doesn't
174 // fragment for me sometimes.
175 {
176 int oval = IP_PMTUDISC_DONT;
177 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
178 }
179 #endif
180
181 sockinfo si (THISNODE, PROT_ICMPv4);
182
183 if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ()))
184 {
185 slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno));
186 exit (1);
187 }
188
189 icmpv4_ev_watcher.start (icmpv4_fd, POLLIN);
190 }
191 #endif
192
193 tcpv4_fd = -1;
194
195 #if ENABLE_TCP
196 if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
197 {
198 tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
199
200 if (tcpv4_fd < 0)
201 return -1;
202
203 fcntl (tcpv4_fd, F_SETFL, O_NONBLOCK);
204
205 // standard daemon practise...
206 {
207 int oval = 1;
208 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
209 }
210
211 sockinfo si (THISNODE, PROT_TCPv4);
212
213 if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
214 {
215 slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
216 exit (1);
217 }
218
219 if (listen (tcpv4_fd, 5))
220 {
221 slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
222 exit (1);
223 }
224
225 tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
226 }
227 #endif
228
229 tap = new tap_device ();
230 if (!tap) //D this, of course, never catches
231 {
232 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
233 exit (1);
234 }
235
236 run_script (run_script_cb (this, &vpn::script_if_up), true);
237
238 tap_ev_watcher.start (tap->fd, POLLIN);
239
240 reconnect_all ();
241
242 return 0;
243 }
244
245 // send a vpn packet out to other hosts
246 bool
247 vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
248 {
249 switch (si.prot)
250 {
251 case PROT_IPv4:
252 return send_ipv4_packet (pkt, si, tos);
253
254 case PROT_UDPv4:
255 return send_udpv4_packet (pkt, si, tos);
256
257 #if ENABLE_TCP
258 case PROT_TCPv4:
259 return send_tcpv4_packet (pkt, si, tos);
260 #endif
261
262 #if ENABLE_ICMP
263 case PROT_ICMPv4:
264 return send_icmpv4_packet (pkt, si, tos);
265 #endif
266
267 default:
268 slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
269 return false;
270 }
271 }
272
273 bool
274 vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
275 {
276 #if defined(SOL_IP) && defined(IP_TOS)
277 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
278 #endif
279 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
280
281 return true;
282 }
283
284 static u16
285 ipv4_checksum (u16 *data, unsigned int len)
286 {
287 // use 32 bit accumulator and fold back carry bits at the end
288 u32 sum = 0;
289
290 while (len > 1)
291 {
292 sum += *data++;
293 len -= 2;
294 }
295
296 // odd byte left?
297 if (len)
298 sum += *(u8 *)data;
299
300 // add back carry bits
301 sum = (sum >> 16) + (sum & 0xffff); // lo += hi
302 sum += (sum >> 16); // carry
303
304 return ~sum;
305 }
306
307 #if ENABLE_ICMP
308 bool
309 vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
310 {
311 #if defined(SOL_IP) && defined(IP_TOS)
312 setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
313 #endif
314
315 pkt->unshift_hdr (4);
316
317 icmp_header *hdr = (icmp_header *)&((*pkt)[0]);
318 hdr->type = ::conf.icmp_type;
319 hdr->code = 255;
320 hdr->checksum = 0;
321 hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);
322
323 sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
324
325 return true;
326 }
327 #endif
328
329 bool
330 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
331 {
332 #if defined(SOL_IP) && defined(IP_TOS)
333 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
334 #endif
335 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
336
337 return true;
338 }
339
340 void
341 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
342 {
343 unsigned int src = pkt->src ();
344 unsigned int dst = pkt->dst ();
345
346 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
347 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
348
349 if (src == 0 || src > conns.size ()
350 || dst > conns.size ()
351 || pkt->typ () >= vpn_packet::PT_MAX)
352 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
353 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
354 else if (dst > conns.size ())
355 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
356 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
357 else
358 {
359 connection *c = conns[src - 1];
360
361 if (dst == 0)
362 slog (L_WARN, _("%s(%s): received broadcast (protocol violation)"),
363 c->conf->nodename, (const char *)rsi);
364 else if (dst != 0 && dst != THISNODE->id)
365 {
366 if (THISNODE->routerprio)
367 // the tos setting gets lost here. who cares.
368 conns[dst - 1]->inject_vpn_packet (pkt);
369 else
370 slog (L_WARN,
371 _("%s(%s): forwarding request (=> %s), but we are no router"),
372 c->conf->nodename, (const char *)rsi,
373 conns[dst - 1]->conf->nodename);
374 }
375 else
376 c->recv_vpn_packet (pkt, rsi);
377 }
378 }
379
380 void
381 vpn::ipv4_ev (io_watcher &w, short revents)
382 {
383 if (revents & (POLLIN | POLLERR))
384 {
385 vpn_packet *pkt = new vpn_packet;
386 struct sockaddr_in sa;
387 socklen_t sa_len = sizeof (sa);
388 int len;
389
390 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
391
392 sockinfo si(sa, PROT_IPv4);
393
394 if (len > 0)
395 {
396 pkt->len = len;
397
398 // raw sockets deliver the ipv4, but don't expect it on sends
399 // this is slow, but...
400 pkt->skip_hdr (IP_OVERHEAD);
401
402 recv_vpn_packet (pkt, si);
403 }
404 else
405 {
406 // probably ECONNRESET or somesuch
407 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
408 }
409
410 delete pkt;
411 }
412 else if (revents & POLLHUP)
413 {
414 // this cannot ;) happen on udp sockets
415 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
416 exit (1);
417 }
418 else
419 {
420 slog (L_ERR,
421 _("FATAL: unknown revents %08x in socket, terminating\n"),
422 revents);
423 exit (1);
424 }
425 }
426
427 #if ENABLE_ICMP
428 void
429 vpn::icmpv4_ev (io_watcher &w, short revents)
430 {
431 if (revents & (POLLIN | POLLERR))
432 {
433 vpn_packet *pkt = new vpn_packet;
434 struct sockaddr_in sa;
435 socklen_t sa_len = sizeof (sa);
436 int len;
437
438 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
439
440 sockinfo si(sa, PROT_ICMPv4);
441
442 if (len > 0)
443 {
444 pkt->len = len;
445
446 icmp_header *hdr = (icmp_header *)&((*pkt)[IP_OVERHEAD]);
447
448 if (hdr->type == ::conf.icmp_type
449 && hdr->code == 255)
450 {
451 // raw sockets deliver the ipv4, but don't expect it on sends
452 // this is slow, but...
453 pkt->skip_hdr (ICMP_OVERHEAD);
454
455 recv_vpn_packet (pkt, si);
456 }
457 }
458 else
459 {
460 // probably ECONNRESET or somesuch
461 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
462 }
463
464 delete pkt;
465 }
466 else if (revents & POLLHUP)
467 {
468 // this cannot ;) happen on udp sockets
469 slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
470 exit (1);
471 }
472 else
473 {
474 slog (L_ERR,
475 _("FATAL: unknown revents %08x in socket, terminating\n"),
476 revents);
477 exit (1);
478 }
479 }
480 #endif
481
482 void
483 vpn::udpv4_ev (io_watcher &w, short revents)
484 {
485 if (revents & (POLLIN | POLLERR))
486 {
487 vpn_packet *pkt = new vpn_packet;
488 struct sockaddr_in sa;
489 socklen_t sa_len = sizeof (sa);
490 int len;
491
492 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
493
494 sockinfo si(sa, PROT_UDPv4);
495
496 if (len > 0)
497 {
498 pkt->len = len;
499
500 recv_vpn_packet (pkt, si);
501 }
502 else
503 {
504 // probably ECONNRESET or somesuch
505 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
506 }
507
508 delete pkt;
509 }
510 else if (revents & POLLHUP)
511 {
512 // this cannot ;) happen on udp sockets
513 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
514 exit (1);
515 }
516 else
517 {
518 slog (L_ERR,
519 _("FATAL: unknown revents %08x in socket, terminating\n"),
520 revents);
521 exit (1);
522 }
523 }
524
525 void
526 vpn::tap_ev (io_watcher &w, short revents)
527 {
528 if (revents & POLLIN)
529 {
530 /* process data */
531 tap_packet *pkt;
532
533 pkt = tap->recv ();
534
535 int dst = mac2id (pkt->dst);
536 int src = mac2id (pkt->src);
537
538 if (src != THISNODE->id)
539 {
540 slog (L_ERR, _("FATAL: tap packet not originating on current node received, exiting."));
541 exit (1);
542 }
543
544 if (dst == THISNODE->id)
545 {
546 slog (L_ERR, _("FATAL: tap packet destined for current node received, exiting."));
547 exit (1);
548 }
549
550 if (dst > conns.size ())
551 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
552 else
553 {
554 if (dst)
555 {
556 // unicast
557 if (dst != THISNODE->id)
558 conns[dst - 1]->inject_data_packet (pkt);
559 }
560 else
561 {
562 // broadcast, this is ugly, but due to the security policy
563 // we have to connect to all hosts...
564 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
565 if ((*c)->conf != THISNODE)
566 (*c)->inject_data_packet (pkt);
567 }
568 }
569
570 delete pkt;
571 }
572 else if (revents & (POLLHUP | POLLERR))
573 {
574 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
575 exit (1);
576 }
577 else
578 abort ();
579 }
580
581 void
582 vpn::event_cb (time_watcher &w)
583 {
584 if (events)
585 {
586 if (events & EVENT_SHUTDOWN)
587 {
588 slog (L_INFO, _("preparing shutdown..."));
589
590 shutdown_all ();
591
592 remove_pid (pidfilename);
593
594 slog (L_INFO, _("terminating"));
595
596 exit (0);
597 }
598
599 if (events & EVENT_RECONNECT)
600 {
601 slog (L_INFO, _("forced reconnect"));
602
603 reconnect_all ();
604 }
605
606 events = 0;
607 }
608
609 w.at = TSTAMP_CANCEL;
610 }
611
612 void
613 vpn::shutdown_all ()
614 {
615 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
616 (*c)->shutdown ();
617 }
618
619 void
620 vpn::reconnect_all ()
621 {
622 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
623 delete *c;
624
625 conns.clear ();
626
627 connection_init ();
628
629 for (configuration::node_vector::iterator i = conf.nodes.begin ();
630 i != conf.nodes.end (); ++i)
631 {
632 connection *conn = new connection (this);
633
634 conn->conf = *i;
635 conns.push_back (conn);
636
637 conn->establish_connection ();
638 }
639 }
640
641 connection *vpn::find_router ()
642 {
643 u32 prio = 1;
644 connection *router = 0;
645
646 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
647 {
648 connection *c = *i;
649
650 if (c->conf->routerprio > prio
651 && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
652 && c->ictx && c->octx
653 && c->conf != THISNODE) // redundant, since ictx==octx==0 always on thisnode
654 {
655 prio = c->conf->routerprio;
656 router = c;
657 }
658 }
659
660 return router;
661 }
662
663 void vpn::send_connect_request (int id)
664 {
665 connection *c = find_router ();
666
667 if (c)
668 c->send_connect_request (id);
669 else
670 // no router found, aggressively connect to all routers
671 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
672 if ((*i)->conf->routerprio && (*i)->conf != THISNODE)
673 (*i)->establish_connection ();
674 }
675
676 void
677 connection::dump_status ()
678 {
679 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
680 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
681 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
682 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
683 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
684 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
685 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
686 }
687
688 void
689 vpn::dump_status ()
690 {
691 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
692
693 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
694 (*c)->dump_status ();
695
696 slog (L_NOTICE, _("END status dump"));
697 }
698
699 vpn::vpn (void)
700 : event (this, &vpn::event_cb)
701 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
702 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
703 #if ENABLE_TCP
704 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
705 #endif
706 #if ENABLE_ICMP
707 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
708 #endif
709 , tap_ev_watcher (this, &vpn::tap_ev)
710 {
711 }
712
713 vpn::~vpn ()
714 {
715 }
716