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Revision: 1.19
Committed: Thu Oct 16 02:41:21 2003 UTC (20 years, 7 months ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.18: +1 -0 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 vpn.C -- handle the protocol, encryption, handshaking etc.
3 Copyright (C) 2003 Marc Lehmann <pcg@goof.com>
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
16 along with this program; if not, write to the Free Software
17 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 #include "config.h"
21
22 #include <list>
23
24 #include <cstdlib>
25 #include <cstring>
26 #include <cstdio>
27
28 #include <sys/types.h>
29 #include <sys/socket.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::inject_data_packet (tap_packet *pkt, int dst)
342 {
343 if (dst)
344 {
345 // unicast
346 if (dst != THISNODE->id)
347 conns[dst - 1]->inject_data_packet (pkt);
348 }
349 else
350 {
351 // broadcast, this is ugly, but due to the security policy
352 // we have to connect to all hosts...
353 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
354 if ((*c)->conf != THISNODE)
355 (*c)->inject_data_packet (pkt, true);
356 }
357 }
358
359 void
360 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
361 {
362 unsigned int src = pkt->src ();
363 unsigned int dst = pkt->dst ();
364
365 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
366 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
367
368 if (src == 0 || src > conns.size ()
369 || dst > conns.size ()
370 || pkt->typ () >= vpn_packet::PT_MAX)
371 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
372 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
373 else if (dst > conns.size ())
374 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
375 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
376 else
377 {
378 connection *c = conns[src - 1];
379
380 if (dst == 0)
381 slog (L_WARN, _("%s(%s): received broadcast (protocol violation)"),
382 c->conf->nodename, (const char *)rsi);
383 else if (dst != THISNODE->id)
384 {
385 if (THISNODE->routerprio)
386 // the tos setting gets lost here. who cares.
387 conns[dst - 1]->inject_vpn_packet (pkt);
388 else
389 slog (L_WARN,
390 _("%s(%s): forwarding request (=> %s), but we are no router"),
391 c->conf->nodename, (const char *)rsi,
392 conns[dst - 1]->conf->nodename);
393 }
394 else
395 c->recv_vpn_packet (pkt, rsi);
396 }
397 }
398
399 void
400 vpn::ipv4_ev (io_watcher &w, short revents)
401 {
402 if (revents & (POLLIN | POLLERR))
403 {
404 vpn_packet *pkt = new vpn_packet;
405 struct sockaddr_in sa;
406 socklen_t sa_len = sizeof (sa);
407 int len;
408
409 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
410
411 sockinfo si(sa, PROT_IPv4);
412
413 if (len > 0)
414 {
415 pkt->len = len;
416
417 // raw sockets deliver the ipv4, but don't expect it on sends
418 // this is slow, but...
419 pkt->skip_hdr (IP_OVERHEAD);
420
421 recv_vpn_packet (pkt, si);
422 }
423 else
424 {
425 // probably ECONNRESET or somesuch
426 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
427 }
428
429 delete pkt;
430 }
431 else if (revents & POLLHUP)
432 {
433 // this cannot ;) happen on udp sockets
434 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
435 exit (1);
436 }
437 else
438 {
439 slog (L_ERR,
440 _("FATAL: unknown revents %08x in socket, terminating\n"),
441 revents);
442 exit (1);
443 }
444 }
445
446 #if ENABLE_ICMP
447 void
448 vpn::icmpv4_ev (io_watcher &w, short revents)
449 {
450 if (revents & (POLLIN | POLLERR))
451 {
452 vpn_packet *pkt = new vpn_packet;
453 struct sockaddr_in sa;
454 socklen_t sa_len = sizeof (sa);
455 int len;
456
457 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
458
459 sockinfo si(sa, PROT_ICMPv4);
460
461 if (len > 0)
462 {
463 pkt->len = len;
464
465 icmp_header *hdr = (icmp_header *)&((*pkt)[IP_OVERHEAD]);
466
467 if (hdr->type == ::conf.icmp_type
468 && hdr->code == 255)
469 {
470 // raw sockets deliver the ipv4, but don't expect it on sends
471 // this is slow, but...
472 pkt->skip_hdr (ICMP_OVERHEAD);
473
474 recv_vpn_packet (pkt, si);
475 }
476 }
477 else
478 {
479 // probably ECONNRESET or somesuch
480 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
481 }
482
483 delete pkt;
484 }
485 else if (revents & POLLHUP)
486 {
487 // this cannot ;) happen on udp sockets
488 slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
489 exit (1);
490 }
491 else
492 {
493 slog (L_ERR,
494 _("FATAL: unknown revents %08x in socket, terminating\n"),
495 revents);
496 exit (1);
497 }
498 }
499 #endif
500
501 void
502 vpn::udpv4_ev (io_watcher &w, short revents)
503 {
504 if (revents & (POLLIN | POLLERR))
505 {
506 vpn_packet *pkt = new vpn_packet;
507 struct sockaddr_in sa;
508 socklen_t sa_len = sizeof (sa);
509 int len;
510
511 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
512
513 sockinfo si(sa, PROT_UDPv4);
514
515 if (len > 0)
516 {
517 pkt->len = len;
518
519 recv_vpn_packet (pkt, si);
520 }
521 else
522 {
523 // probably ECONNRESET or somesuch
524 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
525 }
526
527 delete pkt;
528 }
529 else if (revents & POLLHUP)
530 {
531 // this cannot ;) happen on udp sockets
532 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
533 exit (1);
534 }
535 else
536 {
537 slog (L_ERR,
538 _("FATAL: unknown revents %08x in socket, terminating\n"),
539 revents);
540 exit (1);
541 }
542 }
543
544 void
545 vpn::tap_ev (io_watcher &w, short revents)
546 {
547 if (revents & POLLIN)
548 {
549 /* process data */
550 tap_packet *pkt;
551
552 pkt = tap->recv ();
553
554 if (!pkt)
555 return;
556
557 if (pkt->len > 14)
558 {
559 int dst = mac2id (pkt->dst);
560 int src = mac2id (pkt->src);
561
562 if (src != THISNODE->id)
563 {
564 slog (L_ERR, _("FATAL: tap packet not originating on current node received, exiting."));
565 exit (1);
566 }
567
568 if (dst == THISNODE->id)
569 {
570 slog (L_ERR, _("FATAL: tap packet destined for current node received, exiting."));
571 exit (1);
572 }
573
574 if (dst > conns.size ())
575 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
576 else
577 inject_data_packet (pkt, dst);
578 }
579
580 delete pkt;
581 }
582 else if (revents & (POLLHUP | POLLERR))
583 {
584 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
585 exit (1);
586 }
587 else
588 abort ();
589 }
590
591 void
592 vpn::event_cb (time_watcher &w)
593 {
594 if (events)
595 {
596 if (events & EVENT_SHUTDOWN)
597 {
598 slog (L_INFO, _("preparing shutdown..."));
599
600 shutdown_all ();
601
602 remove_pid (pidfilename);
603
604 slog (L_INFO, _("terminating"));
605
606 exit (0);
607 }
608
609 if (events & EVENT_RECONNECT)
610 {
611 slog (L_INFO, _("forced reconnect"));
612
613 reconnect_all ();
614 }
615
616 events = 0;
617 }
618
619 w.at = TSTAMP_CANCEL;
620 }
621
622 void
623 vpn::shutdown_all ()
624 {
625 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
626 (*c)->shutdown ();
627 }
628
629 void
630 vpn::reconnect_all ()
631 {
632 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
633 delete *c;
634
635 conns.clear ();
636
637 connection_init ();
638
639 for (configuration::node_vector::iterator i = conf.nodes.begin ();
640 i != conf.nodes.end (); ++i)
641 {
642 connection *conn = new connection (this);
643
644 conn->conf = *i;
645 conns.push_back (conn);
646
647 conn->establish_connection ();
648 }
649 }
650
651 connection *vpn::find_router ()
652 {
653 u32 prio = 1;
654 connection *router = 0;
655
656 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
657 {
658 connection *c = *i;
659
660 if (c->conf->routerprio > prio
661 && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
662 && c->ictx && c->octx
663 && c->conf != THISNODE) // redundant, since ictx==octx==0 always on thisnode
664 {
665 prio = c->conf->routerprio;
666 router = c;
667 }
668 }
669
670 return router;
671 }
672
673 void vpn::send_connect_request (int id)
674 {
675 connection *c = find_router ();
676
677 if (c)
678 c->send_connect_request (id);
679 else
680 // no router found, aggressively connect to all routers
681 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
682 if ((*i)->conf->routerprio && (*i)->conf != THISNODE)
683 (*i)->establish_connection ();
684 }
685
686 void
687 connection::dump_status ()
688 {
689 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
690 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
691 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
692 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
693 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
694 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
695 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
696 }
697
698 void
699 vpn::dump_status ()
700 {
701 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
702
703 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
704 (*c)->dump_status ();
705
706 slog (L_NOTICE, _("END status dump"));
707 }
708
709 vpn::vpn (void)
710 : event (this, &vpn::event_cb)
711 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
712 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
713 #if ENABLE_TCP
714 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
715 #endif
716 #if ENABLE_ICMP
717 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
718 #endif
719 , tap_ev_watcher (this, &vpn::tap_ev)
720 {
721 }
722
723 vpn::~vpn ()
724 {
725 }
726