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Revision: 1.23
Committed: Thu Jan 29 18:55:10 2004 UTC (20 years, 3 months ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.22: +14 -14 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 vpn.C -- handle the protocol, encryption, handshaking etc.
3 Copyright (C) 2003-2004 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 <cstdio>
25 #include <cstring>
26 #include <cstdlib>
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 vpn network; // THE vpn (bad design...)
46
47 /////////////////////////////////////////////////////////////////////////////
48
49 const char *vpn::script_if_up ()
50 {
51 // the tunnel device mtu should be the physical mtu - overhead
52 // the tricky part is rounding to the cipher key blocksize
53 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
54 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
55 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
56 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
57
58 char *env;
59 asprintf (&env, "CONFBASE=%s", confbase); putenv (env);
60 asprintf (&env, "NODENAME=%s", THISNODE->nodename); putenv (env);
61 asprintf (&env, "NODEID=%d", THISNODE->id); putenv (env);
62 asprintf (&env, "IFNAME=%s", tap->interface ()); putenv (env);
63 asprintf (&env, "IFTYPE=%s", IFTYPE); putenv (env);
64 asprintf (&env, "IFSUBTYPE=%s", IFSUBTYPE); putenv (env);
65 asprintf (&env, "MTU=%d", mtu); 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 (EXIT_FAILURE);
104 }
105
106 ipv4_ev_watcher.start (ipv4_fd, EVENT_READ);
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 (EXIT_FAILURE);
142 }
143
144 udpv4_ev_watcher.start (udpv4_fd, EVENT_READ);
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 (EXIT_FAILURE);
186 }
187
188 icmpv4_ev_watcher.start (icmpv4_fd, EVENT_READ);
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 (EXIT_FAILURE);
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 (EXIT_FAILURE);
222 }
223
224 tcpv4_ev_watcher.start (tcpv4_fd, EVENT_READ);
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 (EXIT_FAILURE);
233 }
234
235 run_script (run_script_cb (this, &vpn::script_if_up), true);
236
237 tap_ev_watcher.start (tap->fd, EVENT_READ);
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::inject_data_packet (tap_packet *pkt, int dst)
341 {
342 if (dst)
343 {
344 // unicast
345 if (dst != THISNODE->id)
346 conns[dst - 1]->inject_data_packet (pkt);
347 }
348 else
349 {
350 // broadcast, this is ugly, but due to the security policy
351 // we have to connect to all hosts...
352 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
353 if ((*c)->conf != THISNODE)
354 (*c)->inject_data_packet (pkt, true);
355 }
356 }
357
358 void
359 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
360 {
361 unsigned int src = pkt->src ();
362 unsigned int dst = pkt->dst ();
363
364 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
365 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
366
367 if (src == 0 || src > conns.size ()
368 || dst > conns.size ()
369 || pkt->typ () >= vpn_packet::PT_MAX)
370 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
371 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
372 else if (dst > conns.size ())
373 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
374 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
375 else
376 {
377 connection *c = conns[src - 1];
378
379 if (dst == 0)
380 slog (L_WARN, _("%s(%s): received broadcast (protocol violation)"),
381 c->conf->nodename, (const char *)rsi);
382 else if (dst != THISNODE->id)
383 {
384 if (THISNODE->routerprio)
385 // the tos setting gets lost here. who cares.
386 conns[dst - 1]->inject_vpn_packet (pkt);
387 else
388 slog (L_WARN,
389 _("%s(%s): forwarding request (=> %s), but we are no router"),
390 c->conf->nodename, (const char *)rsi,
391 conns[dst - 1]->conf->nodename);
392 }
393 else
394 c->recv_vpn_packet (pkt, rsi);
395 }
396 }
397
398 void
399 vpn::ipv4_ev (io_watcher &w, short revents)
400 {
401 if (revents & EVENT_READ)
402 {
403 vpn_packet *pkt = new vpn_packet;
404 struct sockaddr_in sa;
405 socklen_t sa_len = sizeof (sa);
406 int len;
407
408 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
409
410 sockinfo si(sa, PROT_IPv4);
411
412 if (len > 0)
413 {
414 pkt->len = len;
415
416 // raw sockets deliver the ipv4, but don't expect it on sends
417 // this is slow, but...
418 pkt->skip_hdr (IP_OVERHEAD);
419
420 recv_vpn_packet (pkt, si);
421 }
422 else
423 {
424 // probably ECONNRESET or somesuch
425 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
426 }
427
428 delete pkt;
429 }
430 else
431 {
432 slog (L_ERR,
433 _("FATAL: unknown revents %08x in socket, terminating\n"),
434 revents);
435 exit (EXIT_FAILURE);
436 }
437 }
438
439 #if ENABLE_ICMP
440 void
441 vpn::icmpv4_ev (io_watcher &w, short revents)
442 {
443 if (revents & EVENT_READ)
444 {
445 vpn_packet *pkt = new vpn_packet;
446 struct sockaddr_in sa;
447 socklen_t sa_len = sizeof (sa);
448 int len;
449
450 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
451
452 sockinfo si(sa, PROT_ICMPv4);
453
454 if (len > 0)
455 {
456 pkt->len = len;
457
458 icmp_header *hdr = (icmp_header *)&((*pkt)[IP_OVERHEAD]);
459
460 if (hdr->type == ::conf.icmp_type
461 && hdr->code == 255)
462 {
463 // raw sockets deliver the ipv4, but don't expect it on sends
464 // this is slow, but...
465 pkt->skip_hdr (ICMP_OVERHEAD);
466
467 recv_vpn_packet (pkt, si);
468 }
469 }
470 else
471 {
472 // probably ECONNRESET or somesuch
473 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
474 }
475
476 delete pkt;
477 }
478 else
479 {
480 slog (L_ERR,
481 _("FATAL: unknown revents %08x in socket, terminating\n"),
482 revents);
483 exit (EXIT_FAILURE);
484 }
485 }
486 #endif
487
488 void
489 vpn::udpv4_ev (io_watcher &w, short revents)
490 {
491 if (revents & EVENT_READ)
492 {
493 vpn_packet *pkt = new vpn_packet;
494 struct sockaddr_in sa;
495 socklen_t sa_len = sizeof (sa);
496 int len;
497
498 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
499
500 sockinfo si(sa, PROT_UDPv4);
501
502 if (len > 0)
503 {
504 pkt->len = len;
505
506 recv_vpn_packet (pkt, si);
507 }
508 else
509 {
510 // probably ECONNRESET or somesuch
511 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
512 }
513
514 delete pkt;
515 }
516 else
517 {
518 slog (L_ERR,
519 _("FATAL: unknown revents %08x in socket, terminating\n"),
520 revents);
521 exit (EXIT_FAILURE);
522 }
523 }
524
525 void
526 vpn::tap_ev (io_watcher &w, short revents)
527 {
528 if (revents & EVENT_READ)
529 {
530 /* process data */
531 tap_packet *pkt;
532
533 pkt = tap->recv ();
534
535 if (!pkt)
536 return;
537
538 if (pkt->len > 14)
539 {
540 int dst = mac2id (pkt->dst);
541 int src = mac2id (pkt->src);
542
543 if (src != THISNODE->id)
544 {
545 slog (L_ERR, _("FATAL: tap packet not originating on current node received, exiting."));
546 exit (EXIT_FAILURE);
547 }
548
549 if (dst == THISNODE->id)
550 {
551 slog (L_ERR, _("FATAL: tap packet destined for current node received, exiting."));
552 exit (EXIT_FAILURE);
553 }
554
555 if (dst > conns.size ())
556 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
557 else
558 inject_data_packet (pkt, dst);
559 }
560
561 delete pkt;
562 }
563 else
564 abort ();
565 }
566
567 void
568 vpn::event_cb (time_watcher &w)
569 {
570 if (events)
571 {
572 if (events & EVENT_SHUTDOWN)
573 {
574 slog (L_INFO, _("preparing shutdown..."));
575
576 shutdown_all ();
577 remove_pid (pidfilename);
578 slog (L_INFO, _("terminating"));
579 exit (EXIT_SUCCESS);
580 }
581
582 if (events & EVENT_RECONNECT)
583 {
584 slog (L_INFO, _("forced reconnect"));
585
586 reconnect_all ();
587 }
588
589 events = 0;
590 }
591 }
592
593 void
594 vpn::shutdown_all ()
595 {
596 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
597 (*c)->shutdown ();
598 }
599
600 void
601 vpn::reconnect_all ()
602 {
603 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
604 delete *c;
605
606 conns.clear ();
607
608 connection_init ();
609
610 for (configuration::node_vector::iterator i = conf.nodes.begin ();
611 i != conf.nodes.end (); ++i)
612 {
613 connection *conn = new connection (this);
614
615 conn->conf = *i;
616 conns.push_back (conn);
617
618 conn->establish_connection ();
619 }
620 }
621
622 connection *vpn::find_router ()
623 {
624 u32 prio = 1;
625 connection *router = 0;
626
627 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
628 {
629 connection *c = *i;
630
631 if (c->conf->routerprio > prio
632 && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
633 && c->ictx && c->octx
634 && c->conf != THISNODE) // redundant, since ictx==octx==0 always on thisnode
635 {
636 prio = c->conf->routerprio;
637 router = c;
638 }
639 }
640
641 return router;
642 }
643
644 void vpn::send_connect_request (int id)
645 {
646 connection *c = find_router ();
647
648 if (c)
649 c->send_connect_request (id);
650 else
651 // no router found, aggressively connect to all routers
652 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
653 if ((*i)->conf->routerprio && (*i)->conf != THISNODE)
654 (*i)->establish_connection ();
655 }
656
657 void
658 connection::dump_status ()
659 {
660 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
661 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
662 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
663 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
664 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
665 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
666 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
667 }
668
669 void
670 vpn::dump_status ()
671 {
672 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
673
674 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
675 (*c)->dump_status ();
676
677 slog (L_NOTICE, _("END status dump"));
678 }
679
680 vpn::vpn (void)
681 : event (this, &vpn::event_cb)
682 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
683 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
684 #if ENABLE_TCP
685 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
686 #endif
687 #if ENABLE_ICMP
688 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
689 #endif
690 , tap_ev_watcher (this, &vpn::tap_ev)
691 {
692 }
693
694 vpn::~vpn ()
695 {
696 }
697