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Revision: 1.9
Committed: Tue Apr 8 02:00:54 2003 UTC (21 years, 1 month ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.8: +173 -27 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 <arpa/inet.h>
35 #include <netinet/in.h>
36 #include <netinet/icmp.h>
37
38 #include "pidfile.h"
39
40 #include "connection.h"
41 #include "util.h"
42 #include "vpn.h"
43
44 /////////////////////////////////////////////////////////////////////////////
45
46 const char *vpn::script_if_up ()
47 {
48 // the tunnel device mtu should be the physical mtu - overhead
49 // the tricky part is rounding to the cipher key blocksize
50 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
51 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
52 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
53 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
54
55 char *env;
56 asprintf (&env, "CONFBASE=%s", confbase);
57 putenv (env);
58 asprintf (&env, "NODENAME=%s", THISNODE->nodename);
59 putenv (env);
60 asprintf (&env, "NODEID=%d", THISNODE->id);
61 putenv (env);
62 asprintf (&env, "IFNAME=%s", tap->interface ());
63 putenv (env);
64 asprintf (&env, "MTU=%d", mtu);
65 putenv (env);
66 asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
67 0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
68 THISNODE->id & 0xff);
69 putenv (env);
70
71 return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
72 }
73
74 int
75 vpn::setup ()
76 {
77 ipv4_fd = -1;
78
79 if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto)
80 {
81 ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
82
83 if (ipv4_fd < 0)
84 return -1;
85
86 #ifdef IP_MTU_DISCOVER
87 // this I really consider a linux bug. I am neither connected
88 // nor do I fragment myself. Linux still sets DF and doesn't
89 // fragment for me sometimes.
90 {
91 int oval = IP_PMTUDISC_DONT;
92 setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
93 }
94 #endif
95
96 sockinfo si (THISNODE, PROT_IPv4);
97
98 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
99 {
100 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
101 exit (1);
102 }
103
104 ipv4_ev_watcher.start (ipv4_fd, POLLIN);
105 }
106
107 udpv4_fd = -1;
108
109 if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
110 {
111 udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
112
113 if (udpv4_fd < 0)
114 return -1;
115
116 // standard daemon practise...
117 {
118 int oval = 1;
119 setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
120 }
121
122 #ifdef IP_MTU_DISCOVER
123 // this I really consider a linux bug. I am neither connected
124 // nor do I fragment myself. Linux still sets DF and doesn't
125 // fragment for me sometimes.
126 {
127 int oval = IP_PMTUDISC_DONT;
128 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
129 }
130 #endif
131
132 sockinfo si (THISNODE, PROT_UDPv4);
133
134 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
135 {
136 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
137 exit (1);
138 }
139
140 udpv4_ev_watcher.start (udpv4_fd, POLLIN);
141 }
142
143 icmpv4_fd = -1;
144
145 #if ENABLE_ICMP
146 if (THISNODE->protocols & PROT_ICMPv4)
147 {
148 icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP);
149
150 if (icmpv4_fd < 0)
151 return -1;
152
153 #ifdef ICMP_FILTER
154 {
155 icmp_filter oval;
156 oval.data = 0xffffffff;
157 if (::conf.icmp_type < 32)
158 oval.data &= ~(1 << ::conf.icmp_type);
159
160 setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval);
161 }
162 #endif
163
164 #ifdef IP_MTU_DISCOVER
165 // this I really consider a linux bug. I am neither connected
166 // nor do I fragment myself. Linux still sets DF and doesn't
167 // fragment for me sometimes.
168 {
169 int oval = IP_PMTUDISC_DONT;
170 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
171 }
172 #endif
173
174 sockinfo si (THISNODE, PROT_ICMPv4);
175
176 if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ()))
177 {
178 slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno));
179 exit (1);
180 }
181
182 icmpv4_ev_watcher.start (icmpv4_fd, POLLIN);
183 }
184 #endif
185
186 tcpv4_fd = -1;
187
188 #if ENABLE_TCP
189 if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
190 {
191 tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
192
193 if (tcpv4_fd < 0)
194 return -1;
195
196 // standard daemon practise...
197 {
198 int oval = 1;
199 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
200 }
201
202 sockinfo si (THISNODE, PROT_TCPv4);
203
204 if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
205 {
206 slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
207 exit (1);
208 }
209
210 if (listen (tcpv4_fd, 5))
211 {
212 slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
213 exit (1);
214 }
215
216 tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
217 }
218 #endif
219
220 tap = new tap_device ();
221 if (!tap) //D this, of course, never catches
222 {
223 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
224 exit (1);
225 }
226
227 run_script (run_script_cb (this, &vpn::script_if_up), true);
228
229 tap_ev_watcher.start (tap->fd, POLLIN);
230
231 reconnect_all ();
232
233 return 0;
234 }
235
236 // send a vpn packet out to other hosts
237 bool
238 vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
239 {
240 switch (si.prot)
241 {
242 case PROT_IPv4:
243 return send_ipv4_packet (pkt, si, tos);
244
245 case PROT_UDPv4:
246 return send_udpv4_packet (pkt, si, tos);
247
248 #if ENABLE_TCP
249 case PROT_TCPv4:
250 return send_tcpv4_packet (pkt, si, tos);
251 #endif
252
253 #if ENABLE_ICMP
254 case PROT_ICMPv4:
255 return send_icmpv4_packet (pkt, si, tos);
256 #endif
257
258 default:
259 slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
260 return false;
261 }
262 }
263
264 bool
265 vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
266 {
267 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
268 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
269
270 return true;
271 }
272
273 static u16
274 ipv4_checksum (u16 *data, unsigned int len)
275 {
276 // use 32 bit accumulator and fold back carry bits at the end
277 u32 sum = 0;
278
279 while (len > 1)
280 {
281 sum += *data++;
282 len -= 2;
283 }
284
285 // odd byte left?
286 if (len)
287 sum += *(u8 *)data;
288
289 // add back carry bits
290 sum = (sum >> 16) + (sum & 0xffff); // lo += hi
291 sum += (sum >> 16); // carry
292
293 return ~sum;
294 }
295
296 bool
297 vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
298 {
299 setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
300
301 pkt->unshift_hdr (4);
302
303 icmphdr *hdr = (icmphdr *)&((*pkt)[0]);
304 hdr->type = ::conf.icmp_type;
305 hdr->code = 255;
306 hdr->checksum = 0;
307 hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);
308
309 sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
310
311 return true;
312 }
313
314 bool
315 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
316 {
317 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
318 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
319
320 return true;
321 }
322
323 void
324 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
325 {
326 unsigned int src = pkt->src ();
327 unsigned int dst = pkt->dst ();
328
329 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
330 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
331
332 if (src == 0 || src > conns.size ()
333 || dst > conns.size ()
334 || pkt->typ () >= vpn_packet::PT_MAX)
335 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
336 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
337 else if (dst > conns.size ())
338 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
339 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
340 else
341 {
342 connection *c = conns[src - 1];
343
344 if (dst == 0 && !THISNODE->routerprio)
345 slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
346 c->conf->nodename, (const char *)rsi);
347 else if (dst != 0 && dst != THISNODE->id)
348 {
349 if (THISNODE->routerprio)
350 // the tos setting gets lost here. who cares.
351 conns[dst - 1]->inject_vpn_packet (pkt);
352 else
353 slog (L_WARN,
354 _("%s(%s): forwarding request (=> %s), but we are no router"),
355 c->conf->nodename, (const char *)rsi,
356 conns[dst - 1]->conf->nodename);
357 }
358 else
359 c->recv_vpn_packet (pkt, rsi);
360 }
361 }
362
363 void
364 vpn::ipv4_ev (io_watcher &w, short revents)
365 {
366 if (revents & (POLLIN | POLLERR))
367 {
368 vpn_packet *pkt = new vpn_packet;
369 struct sockaddr_in sa;
370 socklen_t sa_len = sizeof (sa);
371 int len;
372
373 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
374
375 sockinfo si(sa, PROT_IPv4);
376
377 if (len > 0)
378 {
379 pkt->len = len;
380
381 // raw sockets deliver the ipv4, but don't expect it on sends
382 // this is slow, but...
383 pkt->skip_hdr (IP_OVERHEAD);
384
385 recv_vpn_packet (pkt, si);
386 }
387 else
388 {
389 // probably ECONNRESET or somesuch
390 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
391 }
392
393 delete pkt;
394 }
395 else if (revents & POLLHUP)
396 {
397 // this cannot ;) happen on udp sockets
398 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
399 exit (1);
400 }
401 else
402 {
403 slog (L_ERR,
404 _("FATAL: unknown revents %08x in socket, terminating\n"),
405 revents);
406 exit (1);
407 }
408 }
409
410 void
411 vpn::icmpv4_ev (io_watcher &w, short revents)
412 {
413 if (revents & (POLLIN | POLLERR))
414 {
415 vpn_packet *pkt = new vpn_packet;
416 struct sockaddr_in sa;
417 socklen_t sa_len = sizeof (sa);
418 int len;
419
420 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
421
422 sockinfo si(sa, PROT_ICMPv4);
423
424 if (len > 0)
425 {
426 pkt->len = len;
427
428 icmphdr *hdr = (icmphdr *)&((*pkt)[IP_OVERHEAD]);
429
430 if (hdr->type == ::conf.icmp_type
431 && hdr->code == 255)
432 {
433 // raw sockets deliver the ipv4, but don't expect it on sends
434 // this is slow, but...
435 pkt->skip_hdr (ICMP_OVERHEAD);
436
437 recv_vpn_packet (pkt, si);
438 }
439 }
440 else
441 {
442 // probably ECONNRESET or somesuch
443 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
444 }
445
446 delete pkt;
447 }
448 else if (revents & POLLHUP)
449 {
450 // this cannot ;) happen on udp sockets
451 slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
452 exit (1);
453 }
454 else
455 {
456 slog (L_ERR,
457 _("FATAL: unknown revents %08x in socket, terminating\n"),
458 revents);
459 exit (1);
460 }
461 }
462
463 void
464 vpn::udpv4_ev (io_watcher &w, short revents)
465 {
466 if (revents & (POLLIN | POLLERR))
467 {
468 vpn_packet *pkt = new vpn_packet;
469 struct sockaddr_in sa;
470 socklen_t sa_len = sizeof (sa);
471 int len;
472
473 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
474
475 sockinfo si(sa, PROT_UDPv4);
476
477 if (len > 0)
478 {
479 pkt->len = len;
480
481 recv_vpn_packet (pkt, si);
482 }
483 else
484 {
485 // probably ECONNRESET or somesuch
486 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
487 }
488
489 delete pkt;
490 }
491 else if (revents & POLLHUP)
492 {
493 // this cannot ;) happen on udp sockets
494 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
495 exit (1);
496 }
497 else
498 {
499 slog (L_ERR,
500 _("FATAL: unknown revents %08x in socket, terminating\n"),
501 revents);
502 exit (1);
503 }
504 }
505
506 void
507 vpn::tap_ev (io_watcher &w, short revents)
508 {
509 if (revents & POLLIN)
510 {
511 /* process data */
512 tap_packet *pkt;
513
514 pkt = tap->recv ();
515
516 int dst = mac2id (pkt->dst);
517 int src = mac2id (pkt->src);
518
519 if (src != THISNODE->id)
520 {
521 slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
522 exit (1);
523 }
524
525 if (dst == THISNODE->id)
526 {
527 slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
528 exit (1);
529 }
530
531 if (dst > conns.size ())
532 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
533 else
534 {
535 if (dst)
536 {
537 // unicast
538 if (dst != THISNODE->id)
539 conns[dst - 1]->inject_data_packet (pkt);
540 }
541 else
542 {
543 // broadcast, first check router, then self, then english
544 connection *router = find_router ();
545
546 if (router)
547 router->inject_data_packet (pkt, true);
548 else
549 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
550 if ((*c)->conf != THISNODE)
551 (*c)->inject_data_packet (pkt);
552 }
553 }
554
555 delete pkt;
556 }
557 else if (revents & (POLLHUP | POLLERR))
558 {
559 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
560 exit (1);
561 }
562 else
563 abort ();
564 }
565
566 void
567 vpn::event_cb (time_watcher &w)
568 {
569 if (events)
570 {
571 if (events & EVENT_SHUTDOWN)
572 {
573 slog (L_INFO, _("preparing shutdown..."));
574
575 shutdown_all ();
576
577 remove_pid (pidfilename);
578
579 slog (L_INFO, _("terminating"));
580
581 exit (0);
582 }
583
584 if (events & EVENT_RECONNECT)
585 {
586 slog (L_INFO, _("forced reconnect"));
587
588 reconnect_all ();
589 }
590
591 events = 0;
592 }
593
594 w.at = TSTAMP_CANCEL;
595 }
596
597 void
598 vpn::shutdown_all ()
599 {
600 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
601 (*c)->shutdown ();
602 }
603
604 void
605 vpn::reconnect_all ()
606 {
607 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
608 delete *c;
609
610 conns.clear ();
611
612 connection_init ();
613
614 for (configuration::node_vector::iterator i = conf.nodes.begin ();
615 i != conf.nodes.end (); ++i)
616 {
617 connection *conn = new connection (this);
618
619 conn->conf = *i;
620 conns.push_back (conn);
621
622 conn->establish_connection ();
623 }
624 }
625
626 connection *vpn::find_router ()
627 {
628 u32 prio = 0;
629 connection *router = 0;
630
631 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
632 {
633 connection *c = *i;
634
635 if (c->conf->routerprio > prio
636 && c->connectmode == conf_node::C_ALWAYS
637 && c->conf != THISNODE
638 && c->ictx && c->octx)
639 {
640 prio = c->conf->routerprio;
641 router = c;
642 }
643 }
644
645 return router;
646 }
647
648 void vpn::send_connect_request (int id)
649 {
650 connection *c = find_router ();
651
652 if (c)
653 c->send_connect_request (id);
654 else
655 // no router found, aggressively connect to all routers
656 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
657 if ((*i)->conf->routerprio)
658 (*i)->establish_connection ();
659 }
660
661 void
662 connection::dump_status ()
663 {
664 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
665 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
666 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
667 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
668 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
669 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
670 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
671 }
672
673 void
674 vpn::dump_status ()
675 {
676 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
677
678 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
679 (*c)->dump_status ();
680
681 slog (L_NOTICE, _("END status dump"));
682 }
683
684 vpn::vpn (void)
685 : event (this, &vpn::event_cb)
686 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
687 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
688 #if ENABLE_TCP
689 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
690 #endif
691 #if ENABLE_ICMP
692 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
693 #endif
694 , tap_ev_watcher (this, &vpn::tap_ev)
695 {
696 }
697
698 vpn::~vpn ()
699 {
700 }
701