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/cvs/gvpe/src/vpn.C
Revision: 1.16
Committed: Tue Oct 14 19:59:16 2003 UTC (20 years, 7 months ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.15: +0 -1 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/wait.h>
30 #include <errno.h>
31 #include <time.h>
32 #include <unistd.h>
33 #include <fcntl.h>
34 #include <sys/socket.h>
35
36 #include "netcompat.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 fcntl (ipv4_fd, F_SETFL, O_NONBLOCK);
87
88 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
89 // this I really consider a linux bug. I am neither connected
90 // nor do I fragment myself. Linux still sets DF and doesn't
91 // fragment for me sometimes.
92 {
93 int oval = IP_PMTUDISC_DONT;
94 setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
95 }
96 #endif
97
98 sockinfo si (THISNODE, PROT_IPv4);
99
100 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
101 {
102 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
103 exit (1);
104 }
105
106 ipv4_ev_watcher.start (ipv4_fd, POLLIN);
107 }
108
109 udpv4_fd = -1;
110
111 if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
112 {
113 udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
114
115 if (udpv4_fd < 0)
116 return -1;
117
118 fcntl (udpv4_fd, F_SETFL, O_NONBLOCK);
119
120 // standard daemon practise...
121 {
122 int oval = 1;
123 setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
124 }
125
126 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
127 // this I really consider a linux bug. I am neither connected
128 // nor do I fragment myself. Linux still sets DF and doesn't
129 // fragment for me sometimes.
130 {
131 int oval = IP_PMTUDISC_DONT;
132 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
133 }
134 #endif
135
136 sockinfo si (THISNODE, PROT_UDPv4);
137
138 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
139 {
140 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
141 exit (1);
142 }
143
144 udpv4_ev_watcher.start (udpv4_fd, POLLIN);
145 }
146
147 icmpv4_fd = -1;
148
149 #if ENABLE_ICMP
150 if (THISNODE->protocols & PROT_ICMPv4)
151 {
152 icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP);
153
154 if (icmpv4_fd < 0)
155 return -1;
156
157 fcntl (icmpv4_fd, F_SETFL, O_NONBLOCK);
158
159 #ifdef ICMP_FILTER
160 {
161 icmp_filter oval;
162 oval.data = 0xffffffff;
163 if (::conf.icmp_type < 32)
164 oval.data &= ~(1 << ::conf.icmp_type);
165
166 setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval);
167 }
168 #endif
169
170 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
171 // this I really consider a linux bug. I am neither connected
172 // nor do I fragment myself. Linux still sets DF and doesn't
173 // fragment for me sometimes.
174 {
175 int oval = IP_PMTUDISC_DONT;
176 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
177 }
178 #endif
179
180 sockinfo si (THISNODE, PROT_ICMPv4);
181
182 if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ()))
183 {
184 slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno));
185 exit (1);
186 }
187
188 icmpv4_ev_watcher.start (icmpv4_fd, POLLIN);
189 }
190 #endif
191
192 tcpv4_fd = -1;
193
194 #if ENABLE_TCP
195 if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
196 {
197 tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
198
199 if (tcpv4_fd < 0)
200 return -1;
201
202 fcntl (tcpv4_fd, F_SETFL, O_NONBLOCK);
203
204 // standard daemon practise...
205 {
206 int oval = 1;
207 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
208 }
209
210 sockinfo si (THISNODE, PROT_TCPv4);
211
212 if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
213 {
214 slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
215 exit (1);
216 }
217
218 if (listen (tcpv4_fd, 5))
219 {
220 slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
221 exit (1);
222 }
223
224 tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
225 }
226 #endif
227
228 tap = new tap_device ();
229 if (!tap) //D this, of course, never catches
230 {
231 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
232 exit (1);
233 }
234
235 run_script (run_script_cb (this, &vpn::script_if_up), true);
236
237 tap_ev_watcher.start (tap->fd, POLLIN);
238
239 reconnect_all ();
240
241 return 0;
242 }
243
244 // send a vpn packet out to other hosts
245 bool
246 vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
247 {
248 switch (si.prot)
249 {
250 case PROT_IPv4:
251 return send_ipv4_packet (pkt, si, tos);
252
253 case PROT_UDPv4:
254 return send_udpv4_packet (pkt, si, tos);
255
256 #if ENABLE_TCP
257 case PROT_TCPv4:
258 return send_tcpv4_packet (pkt, si, tos);
259 #endif
260
261 #if ENABLE_ICMP
262 case PROT_ICMPv4:
263 return send_icmpv4_packet (pkt, si, tos);
264 #endif
265
266 default:
267 slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
268 return false;
269 }
270 }
271
272 bool
273 vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
274 {
275 #if defined(SOL_IP) && defined(IP_TOS)
276 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
277 #endif
278 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
279
280 return true;
281 }
282
283 static u16
284 ipv4_checksum (u16 *data, unsigned int len)
285 {
286 // use 32 bit accumulator and fold back carry bits at the end
287 u32 sum = 0;
288
289 while (len > 1)
290 {
291 sum += *data++;
292 len -= 2;
293 }
294
295 // odd byte left?
296 if (len)
297 sum += *(u8 *)data;
298
299 // add back carry bits
300 sum = (sum >> 16) + (sum & 0xffff); // lo += hi
301 sum += (sum >> 16); // carry
302
303 return ~sum;
304 }
305
306 #if ENABLE_ICMP
307 bool
308 vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
309 {
310 #if defined(SOL_IP) && defined(IP_TOS)
311 setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
312 #endif
313
314 pkt->unshift_hdr (4);
315
316 icmp_header *hdr = (icmp_header *)&((*pkt)[0]);
317 hdr->type = ::conf.icmp_type;
318 hdr->code = 255;
319 hdr->checksum = 0;
320 hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);
321
322 sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
323
324 return true;
325 }
326 #endif
327
328 bool
329 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
330 {
331 #if defined(SOL_IP) && defined(IP_TOS)
332 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
333 #endif
334 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
335
336 return true;
337 }
338
339 void
340 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
341 {
342 unsigned int src = pkt->src ();
343 unsigned int dst = pkt->dst ();
344
345 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
346 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
347
348 if (src == 0 || src > conns.size ()
349 || dst > conns.size ()
350 || pkt->typ () >= vpn_packet::PT_MAX)
351 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
352 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
353 else if (dst > conns.size ())
354 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
355 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
356 else
357 {
358 connection *c = conns[src - 1];
359
360 if (dst == 0)
361 slog (L_WARN, _("%s(%s): received broadcast (protocol violation)"),
362 c->conf->nodename, (const char *)rsi);
363 else if (dst != 0 && dst != THISNODE->id)
364 {
365 if (THISNODE->routerprio)
366 // the tos setting gets lost here. who cares.
367 conns[dst - 1]->inject_vpn_packet (pkt);
368 else
369 slog (L_WARN,
370 _("%s(%s): forwarding request (=> %s), but we are no router"),
371 c->conf->nodename, (const char *)rsi,
372 conns[dst - 1]->conf->nodename);
373 }
374 else
375 c->recv_vpn_packet (pkt, rsi);
376 }
377 }
378
379 void
380 vpn::ipv4_ev (io_watcher &w, short revents)
381 {
382 if (revents & (POLLIN | POLLERR))
383 {
384 vpn_packet *pkt = new vpn_packet;
385 struct sockaddr_in sa;
386 socklen_t sa_len = sizeof (sa);
387 int len;
388
389 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
390
391 sockinfo si(sa, PROT_IPv4);
392
393 if (len > 0)
394 {
395 pkt->len = len;
396
397 // raw sockets deliver the ipv4, but don't expect it on sends
398 // this is slow, but...
399 pkt->skip_hdr (IP_OVERHEAD);
400
401 recv_vpn_packet (pkt, si);
402 }
403 else
404 {
405 // probably ECONNRESET or somesuch
406 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
407 }
408
409 delete pkt;
410 }
411 else if (revents & POLLHUP)
412 {
413 // this cannot ;) happen on udp sockets
414 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
415 exit (1);
416 }
417 else
418 {
419 slog (L_ERR,
420 _("FATAL: unknown revents %08x in socket, terminating\n"),
421 revents);
422 exit (1);
423 }
424 }
425
426 #if ENABLE_ICMP
427 void
428 vpn::icmpv4_ev (io_watcher &w, short revents)
429 {
430 if (revents & (POLLIN | POLLERR))
431 {
432 vpn_packet *pkt = new vpn_packet;
433 struct sockaddr_in sa;
434 socklen_t sa_len = sizeof (sa);
435 int len;
436
437 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
438
439 sockinfo si(sa, PROT_ICMPv4);
440
441 if (len > 0)
442 {
443 pkt->len = len;
444
445 icmp_header *hdr = (icmp_header *)&((*pkt)[IP_OVERHEAD]);
446
447 if (hdr->type == ::conf.icmp_type
448 && hdr->code == 255)
449 {
450 // raw sockets deliver the ipv4, but don't expect it on sends
451 // this is slow, but...
452 pkt->skip_hdr (ICMP_OVERHEAD);
453
454 recv_vpn_packet (pkt, si);
455 }
456 }
457 else
458 {
459 // probably ECONNRESET or somesuch
460 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
461 }
462
463 delete pkt;
464 }
465 else if (revents & POLLHUP)
466 {
467 // this cannot ;) happen on udp sockets
468 slog (L_ERR, _("FATAL: POLLHUP on icmpv4 fd, terminating."));
469 exit (1);
470 }
471 else
472 {
473 slog (L_ERR,
474 _("FATAL: unknown revents %08x in socket, terminating\n"),
475 revents);
476 exit (1);
477 }
478 }
479 #endif
480
481 void
482 vpn::udpv4_ev (io_watcher &w, short revents)
483 {
484 if (revents & (POLLIN | POLLERR))
485 {
486 vpn_packet *pkt = new vpn_packet;
487 struct sockaddr_in sa;
488 socklen_t sa_len = sizeof (sa);
489 int len;
490
491 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
492
493 sockinfo si(sa, PROT_UDPv4);
494
495 if (len > 0)
496 {
497 pkt->len = len;
498
499 recv_vpn_packet (pkt, si);
500 }
501 else
502 {
503 // probably ECONNRESET or somesuch
504 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
505 }
506
507 delete pkt;
508 }
509 else if (revents & POLLHUP)
510 {
511 // this cannot ;) happen on udp sockets
512 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
513 exit (1);
514 }
515 else
516 {
517 slog (L_ERR,
518 _("FATAL: unknown revents %08x in socket, terminating\n"),
519 revents);
520 exit (1);
521 }
522 }
523
524 void
525 vpn::tap_ev (io_watcher &w, short revents)
526 {
527 if (revents & POLLIN)
528 {
529 /* process data */
530 tap_packet *pkt;
531
532 pkt = tap->recv ();
533
534 int dst = mac2id (pkt->dst);
535 int src = mac2id (pkt->src);
536
537 if (src != THISNODE->id)
538 {
539 slog (L_ERR, _("FATAL: tap packet not originating on current node received, exiting."));
540 exit (1);
541 }
542
543 if (dst == THISNODE->id)
544 {
545 slog (L_ERR, _("FATAL: tap packet destined for current node received, exiting."));
546 exit (1);
547 }
548
549 if (dst > conns.size ())
550 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
551 else
552 {
553 if (dst)
554 {
555 // unicast
556 if (dst != THISNODE->id)
557 conns[dst - 1]->inject_data_packet (pkt);
558 }
559 else
560 {
561 // broadcast, this is ugly, but due to the security policy
562 // we have to connect to all hosts...
563 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
564 if ((*c)->conf != THISNODE)
565 (*c)->inject_data_packet (pkt);
566 }
567 }
568
569 delete pkt;
570 }
571 else if (revents & (POLLHUP | POLLERR))
572 {
573 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
574 exit (1);
575 }
576 else
577 abort ();
578 }
579
580 void
581 vpn::event_cb (time_watcher &w)
582 {
583 if (events)
584 {
585 if (events & EVENT_SHUTDOWN)
586 {
587 slog (L_INFO, _("preparing shutdown..."));
588
589 shutdown_all ();
590
591 remove_pid (pidfilename);
592
593 slog (L_INFO, _("terminating"));
594
595 exit (0);
596 }
597
598 if (events & EVENT_RECONNECT)
599 {
600 slog (L_INFO, _("forced reconnect"));
601
602 reconnect_all ();
603 }
604
605 events = 0;
606 }
607
608 w.at = TSTAMP_CANCEL;
609 }
610
611 void
612 vpn::shutdown_all ()
613 {
614 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
615 (*c)->shutdown ();
616 }
617
618 void
619 vpn::reconnect_all ()
620 {
621 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
622 delete *c;
623
624 conns.clear ();
625
626 connection_init ();
627
628 for (configuration::node_vector::iterator i = conf.nodes.begin ();
629 i != conf.nodes.end (); ++i)
630 {
631 connection *conn = new connection (this);
632
633 conn->conf = *i;
634 conns.push_back (conn);
635
636 conn->establish_connection ();
637 }
638 }
639
640 connection *vpn::find_router ()
641 {
642 u32 prio = 1;
643 connection *router = 0;
644
645 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
646 {
647 connection *c = *i;
648
649 if (c->conf->routerprio > prio
650 && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
651 && c->ictx && c->octx
652 && c->conf != THISNODE) // redundant, since ictx==octx==0 always on thisnode
653 {
654 prio = c->conf->routerprio;
655 router = c;
656 }
657 }
658
659 return router;
660 }
661
662 void vpn::send_connect_request (int id)
663 {
664 connection *c = find_router ();
665
666 if (c)
667 c->send_connect_request (id);
668 else
669 // no router found, aggressively connect to all routers
670 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
671 if ((*i)->conf->routerprio && (*i)->conf != THISNODE)
672 (*i)->establish_connection ();
673 }
674
675 void
676 connection::dump_status ()
677 {
678 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
679 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
680 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
681 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
682 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
683 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
684 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
685 }
686
687 void
688 vpn::dump_status ()
689 {
690 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
691
692 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
693 (*c)->dump_status ();
694
695 slog (L_NOTICE, _("END status dump"));
696 }
697
698 vpn::vpn (void)
699 : event (this, &vpn::event_cb)
700 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
701 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
702 #if ENABLE_TCP
703 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
704 #endif
705 #if ENABLE_ICMP
706 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
707 #endif
708 , tap_ev_watcher (this, &vpn::tap_ev)
709 {
710 }
711
712 vpn::~vpn ()
713 {
714 }
715