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/cvs/gvpe/src/vpn.C
Revision: 1.12
Committed: Sun Apr 13 00:42:04 2003 UTC (21 years, 1 month ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.11: +2 -2 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 <arpa/inet.h>
36 #include <netinet/in.h>
37 #include <netinet/ip_icmp.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 #ifdef 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 #ifdef 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 #ifdef 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 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
277 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
278
279 return true;
280 }
281
282 static u16
283 ipv4_checksum (u16 *data, unsigned int len)
284 {
285 // use 32 bit accumulator and fold back carry bits at the end
286 u32 sum = 0;
287
288 while (len > 1)
289 {
290 sum += *data++;
291 len -= 2;
292 }
293
294 // odd byte left?
295 if (len)
296 sum += *(u8 *)data;
297
298 // add back carry bits
299 sum = (sum >> 16) + (sum & 0xffff); // lo += hi
300 sum += (sum >> 16); // carry
301
302 return ~sum;
303 }
304
305 bool
306 vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
307 {
308 setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
309
310 pkt->unshift_hdr (4);
311
312 icmphdr *hdr = (icmphdr *)&((*pkt)[0]);
313 hdr->type = ::conf.icmp_type;
314 hdr->code = 255;
315 hdr->checksum = 0;
316 hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);
317
318 sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
319
320 return true;
321 }
322
323 bool
324 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
325 {
326 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
327 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
328
329 return true;
330 }
331
332 void
333 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
334 {
335 unsigned int src = pkt->src ();
336 unsigned int dst = pkt->dst ();
337
338 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
339 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
340
341 if (src == 0 || src > conns.size ()
342 || dst > conns.size ()
343 || pkt->typ () >= vpn_packet::PT_MAX)
344 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
345 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
346 else if (dst > conns.size ())
347 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
348 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
349 else
350 {
351 connection *c = conns[src - 1];
352
353 if (dst == 0 && !THISNODE->routerprio)
354 slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
355 c->conf->nodename, (const char *)rsi);
356 else if (dst != 0 && dst != THISNODE->id)
357 {
358 if (THISNODE->routerprio)
359 // the tos setting gets lost here. who cares.
360 conns[dst - 1]->inject_vpn_packet (pkt);
361 else
362 slog (L_WARN,
363 _("%s(%s): forwarding request (=> %s), but we are no router"),
364 c->conf->nodename, (const char *)rsi,
365 conns[dst - 1]->conf->nodename);
366 }
367 else
368 c->recv_vpn_packet (pkt, rsi);
369 }
370 }
371
372 void
373 vpn::ipv4_ev (io_watcher &w, short revents)
374 {
375 if (revents & (POLLIN | POLLERR))
376 {
377 vpn_packet *pkt = new vpn_packet;
378 struct sockaddr_in sa;
379 socklen_t sa_len = sizeof (sa);
380 int len;
381
382 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
383
384 sockinfo si(sa, PROT_IPv4);
385
386 if (len > 0)
387 {
388 pkt->len = len;
389
390 // raw sockets deliver the ipv4, but don't expect it on sends
391 // this is slow, but...
392 pkt->skip_hdr (IP_OVERHEAD);
393
394 recv_vpn_packet (pkt, si);
395 }
396 else
397 {
398 // probably ECONNRESET or somesuch
399 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
400 }
401
402 delete pkt;
403 }
404 else if (revents & POLLHUP)
405 {
406 // this cannot ;) happen on udp sockets
407 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
408 exit (1);
409 }
410 else
411 {
412 slog (L_ERR,
413 _("FATAL: unknown revents %08x in socket, terminating\n"),
414 revents);
415 exit (1);
416 }
417 }
418
419 void
420 vpn::icmpv4_ev (io_watcher &w, short revents)
421 {
422 if (revents & (POLLIN | POLLERR))
423 {
424 vpn_packet *pkt = new vpn_packet;
425 struct sockaddr_in sa;
426 socklen_t sa_len = sizeof (sa);
427 int len;
428
429 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
430
431 sockinfo si(sa, PROT_ICMPv4);
432
433 if (len > 0)
434 {
435 pkt->len = len;
436
437 icmphdr *hdr = (icmphdr *)&((*pkt)[IP_OVERHEAD]);
438
439 if (hdr->type == ::conf.icmp_type
440 && hdr->code == 255)
441 {
442 // raw sockets deliver the ipv4, but don't expect it on sends
443 // this is slow, but...
444 pkt->skip_hdr (ICMP_OVERHEAD);
445
446 recv_vpn_packet (pkt, si);
447 }
448 }
449 else
450 {
451 // probably ECONNRESET or somesuch
452 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
453 }
454
455 delete pkt;
456 }
457 else if (revents & POLLHUP)
458 {
459 // this cannot ;) happen on udp sockets
460 slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
461 exit (1);
462 }
463 else
464 {
465 slog (L_ERR,
466 _("FATAL: unknown revents %08x in socket, terminating\n"),
467 revents);
468 exit (1);
469 }
470 }
471
472 void
473 vpn::udpv4_ev (io_watcher &w, short revents)
474 {
475 if (revents & (POLLIN | POLLERR))
476 {
477 vpn_packet *pkt = new vpn_packet;
478 struct sockaddr_in sa;
479 socklen_t sa_len = sizeof (sa);
480 int len;
481
482 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
483
484 sockinfo si(sa, PROT_UDPv4);
485
486 if (len > 0)
487 {
488 pkt->len = len;
489
490 recv_vpn_packet (pkt, si);
491 }
492 else
493 {
494 // probably ECONNRESET or somesuch
495 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
496 }
497
498 delete pkt;
499 }
500 else if (revents & POLLHUP)
501 {
502 // this cannot ;) happen on udp sockets
503 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
504 exit (1);
505 }
506 else
507 {
508 slog (L_ERR,
509 _("FATAL: unknown revents %08x in socket, terminating\n"),
510 revents);
511 exit (1);
512 }
513 }
514
515 void
516 vpn::tap_ev (io_watcher &w, short revents)
517 {
518 if (revents & POLLIN)
519 {
520 /* process data */
521 tap_packet *pkt;
522
523 pkt = tap->recv ();
524
525 int dst = mac2id (pkt->dst);
526 int src = mac2id (pkt->src);
527
528 if (src != THISNODE->id)
529 {
530 slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
531 exit (1);
532 }
533
534 if (dst == THISNODE->id)
535 {
536 slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
537 exit (1);
538 }
539
540 if (dst > conns.size ())
541 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
542 else
543 {
544 if (dst)
545 {
546 // unicast
547 if (dst != THISNODE->id)
548 conns[dst - 1]->inject_data_packet (pkt);
549 }
550 else
551 {
552 // broadcast, first check router, then self, then english
553 connection *router = find_router ();
554
555 if (router)
556 router->inject_data_packet (pkt, true);
557 else
558 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
559 if ((*c)->conf != THISNODE)
560 (*c)->inject_data_packet (pkt);
561 }
562 }
563
564 delete pkt;
565 }
566 else if (revents & (POLLHUP | POLLERR))
567 {
568 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
569 exit (1);
570 }
571 else
572 abort ();
573 }
574
575 void
576 vpn::event_cb (time_watcher &w)
577 {
578 if (events)
579 {
580 if (events & EVENT_SHUTDOWN)
581 {
582 slog (L_INFO, _("preparing shutdown..."));
583
584 shutdown_all ();
585
586 remove_pid (pidfilename);
587
588 slog (L_INFO, _("terminating"));
589
590 exit (0);
591 }
592
593 if (events & EVENT_RECONNECT)
594 {
595 slog (L_INFO, _("forced reconnect"));
596
597 reconnect_all ();
598 }
599
600 events = 0;
601 }
602
603 w.at = TSTAMP_CANCEL;
604 }
605
606 void
607 vpn::shutdown_all ()
608 {
609 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
610 (*c)->shutdown ();
611 }
612
613 void
614 vpn::reconnect_all ()
615 {
616 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
617 delete *c;
618
619 conns.clear ();
620
621 connection_init ();
622
623 for (configuration::node_vector::iterator i = conf.nodes.begin ();
624 i != conf.nodes.end (); ++i)
625 {
626 connection *conn = new connection (this);
627
628 conn->conf = *i;
629 conns.push_back (conn);
630
631 conn->establish_connection ();
632 }
633 }
634
635 connection *vpn::find_router ()
636 {
637 u32 prio = 1;
638 connection *router = 0;
639
640 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
641 {
642 connection *c = *i;
643
644 if (c->conf->routerprio >= prio
645 && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
646 && c->ictx && c->octx
647 && c->conf != THISNODE // redundant, since ictx==octx==0 always on thisnode
648 && (!THISNODE->routerprio
649 || c->conf->routerprio <= THISNODE->routerprio))
650 {
651 prio = c->conf->routerprio;
652 router = c;
653 }
654 }
655
656 return router;
657 }
658
659 void vpn::send_connect_request (int id)
660 {
661 connection *c = find_router ();
662
663 if (c)
664 c->send_connect_request (id);
665 else
666 // no router found, aggressively connect to all routers
667 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
668 if ((*i)->conf->routerprio)
669 (*i)->establish_connection ();
670 }
671
672 void
673 connection::dump_status ()
674 {
675 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
676 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
677 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
678 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
679 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
680 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
681 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
682 }
683
684 void
685 vpn::dump_status ()
686 {
687 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
688
689 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
690 (*c)->dump_status ();
691
692 slog (L_NOTICE, _("END status dump"));
693 }
694
695 vpn::vpn (void)
696 : event (this, &vpn::event_cb)
697 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
698 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
699 #if ENABLE_TCP
700 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
701 #endif
702 #if ENABLE_ICMP
703 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
704 #endif
705 , tap_ev_watcher (this, &vpn::tap_ev)
706 {
707 }
708
709 vpn::~vpn ()
710 {
711 }
712