ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/gvpe/src/vpn.C
Revision: 1.30
Committed: Fri Mar 4 20:26:50 2005 UTC (19 years, 3 months ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.29: +4 -5 lines
Log Message:
*** empty log message ***

File Contents

# Content
1 /*
2 vpn.C -- handle the protocol, encryption, handshaking etc.
3 Copyright (C) 2003-2005 Marc Lehmann <gvpe@schmorp.de>
4
5 This file is part of GVPE.
6
7 GVPE is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with gvpe; if not, write to the Free Software
19 Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include "config.h"
23
24 #include <list>
25
26 #include <cstdio>
27 #include <cstring>
28 #include <cstdlib>
29
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #include <sys/wait.h>
33 #include <errno.h>
34 #include <time.h>
35 #include <unistd.h>
36 #include <fcntl.h>
37 #include <sys/socket.h>
38
39 #include "netcompat.h"
40
41 #include "pidfile.h"
42
43 #include "connection.h"
44 #include "util.h"
45 #include "vpn.h"
46
47 vpn network; // THE vpn (bad design...)
48
49 /////////////////////////////////////////////////////////////////////////////
50
51 const char *vpn::script_if_up ()
52 {
53 // the tunnel device mtu should be the physical mtu - overhead
54 // the tricky part is rounding to the cipher key blocksize
55 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
56 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
57 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
58 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
59
60 char *env;
61 asprintf (&env, "CONFBASE=%s", confbase); putenv (env);
62 asprintf (&env, "NODENAME=%s", THISNODE->nodename); putenv (env);
63 asprintf (&env, "NODEID=%d", THISNODE->id); putenv (env);
64 asprintf (&env, "IFNAME=%s", tap->interface ()); putenv (env);
65 asprintf (&env, "IFTYPE=%s", IFTYPE); putenv (env);
66 asprintf (&env, "IFSUBTYPE=%s", IFSUBTYPE); putenv (env);
67 asprintf (&env, "MTU=%d", mtu); putenv (env);
68 asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
69 0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
70 THISNODE->id & 0xff);
71 putenv (env);
72
73 return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
74 }
75
76 int
77 vpn::setup ()
78 {
79 ipv4_fd = -1;
80
81 if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto)
82 {
83 ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
84
85 if (ipv4_fd < 0)
86 return -1;
87
88 fcntl (ipv4_fd, F_SETFL, O_NONBLOCK);
89
90 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
91 // this I really consider a linux bug. I am neither connected
92 // nor do I fragment myself. Linux still sets DF and doesn't
93 // fragment for me sometimes.
94 {
95 int oval = IP_PMTUDISC_DONT;
96 setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
97 }
98 #endif
99
100 sockinfo si (THISNODE, PROT_IPv4);
101
102 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
103 {
104 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
105 exit (EXIT_FAILURE);
106 }
107
108 ipv4_ev_watcher.start (ipv4_fd, EVENT_READ);
109 }
110
111 udpv4_fd = -1;
112
113 if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
114 {
115 udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
116
117 if (udpv4_fd < 0)
118 return -1;
119
120 fcntl (udpv4_fd, F_SETFL, O_NONBLOCK);
121
122 // standard daemon practise...
123 {
124 int oval = 1;
125 setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
126 }
127
128 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
129 // this I really consider a linux bug. I am neither connected
130 // nor do I fragment myself. Linux still sets DF and doesn't
131 // fragment for me sometimes.
132 {
133 int oval = IP_PMTUDISC_DONT;
134 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
135 }
136 #endif
137
138 sockinfo si (THISNODE, PROT_UDPv4);
139
140 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
141 {
142 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
143 exit (EXIT_FAILURE);
144 }
145
146 udpv4_ev_watcher.start (udpv4_fd, EVENT_READ);
147 }
148
149 icmpv4_fd = -1;
150
151 #if ENABLE_ICMP
152 if (THISNODE->protocols & PROT_ICMPv4)
153 {
154 icmpv4_fd = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP);
155
156 if (icmpv4_fd < 0)
157 return -1;
158
159 fcntl (icmpv4_fd, F_SETFL, O_NONBLOCK);
160
161 #ifdef ICMP_FILTER
162 {
163 icmp_filter oval;
164 oval.data = 0xffffffff;
165 if (::conf.icmp_type < 32)
166 oval.data &= ~(1 << ::conf.icmp_type);
167
168 setsockopt (icmpv4_fd, SOL_RAW, ICMP_FILTER, &oval, sizeof oval);
169 }
170 #endif
171
172 #if defined(SOL_IP) && defined(IP_MTU_DISCOVER)
173 // this I really consider a linux bug. I am neither connected
174 // nor do I fragment myself. Linux still sets DF and doesn't
175 // fragment for me sometimes.
176 {
177 int oval = IP_PMTUDISC_DONT;
178 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
179 }
180 #endif
181
182 sockinfo si (THISNODE, PROT_ICMPv4);
183
184 if (bind (icmpv4_fd, si.sav4 (), si.salenv4 ()))
185 {
186 slog (L_ERR, _("can't bind icmpv4 on %s: %s"), (const char *)si, strerror (errno));
187 exit (EXIT_FAILURE);
188 }
189
190 icmpv4_ev_watcher.start (icmpv4_fd, EVENT_READ);
191 }
192 #endif
193
194 tcpv4_fd = -1;
195
196 #if ENABLE_TCP
197 if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
198 {
199 tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
200
201 if (tcpv4_fd < 0)
202 return -1;
203
204 fcntl (tcpv4_fd, F_SETFL, O_NONBLOCK);
205
206 // standard daemon practise...
207 {
208 int oval = 1;
209 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
210 }
211
212 sockinfo si (THISNODE, PROT_TCPv4);
213
214 if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
215 {
216 slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
217 exit (EXIT_FAILURE);
218 }
219
220 if (listen (tcpv4_fd, 5))
221 {
222 slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
223 exit (EXIT_FAILURE);
224 }
225
226 tcpv4_ev_watcher.start (tcpv4_fd, EVENT_READ);
227 }
228 #endif
229
230 #if ENABLE_DNS
231 if (THISNODE->protocols & PROT_DNSv4)
232 {
233 dns_forwarder.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
234
235 dnsv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
236
237 if (dnsv4_fd < 0)
238 return -1;
239
240 // standard daemon practise...
241 {
242 int oval = 1;
243 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
244 }
245
246 sockinfo si (THISNODE, PROT_DNSv4);
247
248 if (bind (dnsv4_fd, si.sav4 (), si.salenv4 ()))
249 {
250 slog (L_ERR, _("can't bind dnsv4 on %s: %s"), (const char *)si, strerror (errno));
251 exit (EXIT_FAILURE);
252 }
253
254 dnsv4_ev_watcher.start (dnsv4_fd, EVENT_READ);
255 }
256 #endif
257
258 tap = new tap_device ();
259 if (!tap) //D this, of course, never catches
260 {
261 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
262 exit (EXIT_FAILURE);
263 }
264
265 run_script (run_script_cb (this, &vpn::script_if_up), true);
266
267 tap_ev_watcher.start (tap->fd, EVENT_READ);
268
269 reconnect_all ();
270
271 return 0;
272 }
273
274 bool
275 vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
276 {
277 #if defined(SOL_IP) && defined(IP_TOS)
278 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
279 #endif
280 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
281
282 return true;
283 }
284
285 static u16
286 ipv4_checksum (u16 *data, unsigned int len)
287 {
288 // use 32 bit accumulator and fold back carry bits at the end
289 u32 sum = 0;
290
291 while (len > 1)
292 {
293 sum += *data++;
294 len -= 2;
295 }
296
297 // odd byte left?
298 if (len)
299 sum += *(u8 *)data;
300
301 // add back carry bits
302 sum = (sum >> 16) + (sum & 0xffff); // lo += hi
303 sum += (sum >> 16); // carry
304
305 return ~sum;
306 }
307
308 #if ENABLE_ICMP
309 bool
310 vpn::send_icmpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
311 {
312 #if defined(SOL_IP) && defined(IP_TOS)
313 setsockopt (icmpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
314 #endif
315
316 pkt->unshift_hdr (4);
317
318 icmp_header *hdr = (icmp_header *)&((*pkt)[0]);
319 hdr->type = ::conf.icmp_type;
320 hdr->code = 255;
321 hdr->checksum = 0;
322 hdr->checksum = ipv4_checksum ((u16 *)hdr, pkt->len);
323
324 sendto (icmpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
325
326 return true;
327 }
328 #endif
329
330 bool
331 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
332 {
333 #if defined(SOL_IP) && defined(IP_TOS)
334 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
335 #endif
336 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
337
338 return true;
339 }
340
341 void
342 vpn::inject_data_packet (tap_packet *pkt, int dst)
343 {
344 if (dst)
345 {
346 // unicast
347 if (dst != THISNODE->id)
348 conns[dst - 1]->inject_data_packet (pkt);
349 }
350 else
351 {
352 // broadcast, this is ugly, but due to the security policy
353 // we have to connect to all hosts...
354 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
355 if ((*c)->conf != THISNODE)
356 (*c)->inject_data_packet (pkt, true);
357 }
358 }
359
360 void
361 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
362 {
363 unsigned int src = pkt->src ();
364 unsigned int dst = pkt->dst ();
365
366 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
367 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
368
369 if (src == 0 || src > conns.size ()
370 || dst > conns.size ()
371 || pkt->typ () >= vpn_packet::PT_MAX)
372 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
373 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
374 else if (dst > conns.size ())
375 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
376 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
377 else
378 {
379 connection *c = conns[src - 1];
380
381 if (dst == 0)
382 slog (L_WARN, _("%s(%s): received broadcast (protocol violation)"),
383 c->conf->nodename, (const char *)rsi);
384 else if (dst != THISNODE->id)
385 {
386 if (THISNODE->routerprio)
387 // the tos setting gets lost here. who cares.
388 conns[dst - 1]->inject_vpn_packet (pkt);
389 else
390 slog (L_WARN,
391 _("%s(%s): forwarding request (=> %s), but we are no router"),
392 c->conf->nodename, (const char *)rsi,
393 conns[dst - 1]->conf->nodename);
394 }
395 else
396 c->recv_vpn_packet (pkt, rsi);
397 }
398 }
399
400 void
401 vpn::ipv4_ev (io_watcher &w, short revents)
402 {
403 if (revents & EVENT_READ)
404 {
405 vpn_packet *pkt = new vpn_packet;
406 struct sockaddr_in sa;
407 socklen_t sa_len = sizeof (sa);
408 int len;
409
410 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
411
412 sockinfo si(sa, PROT_IPv4);
413
414 if (len > 0)
415 {
416 pkt->len = len;
417
418 // raw sockets deliver the ipv4 header, but don't expect it on sends
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
432 {
433 slog (L_ERR,
434 _("FATAL: unknown revents %08x in socket, terminating\n"),
435 revents);
436 exit (EXIT_FAILURE);
437 }
438 }
439
440 #if ENABLE_ICMP
441 void
442 vpn::icmpv4_ev (io_watcher &w, short revents)
443 {
444 if (revents & EVENT_READ)
445 {
446 vpn_packet *pkt = new vpn_packet;
447 struct sockaddr_in sa;
448 socklen_t sa_len = sizeof (sa);
449 int len;
450
451 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
452
453 sockinfo si(sa, PROT_ICMPv4);
454
455 if (len > 0)
456 {
457 pkt->len = len;
458
459 icmp_header *hdr = (icmp_header *)&((*pkt)[IP_OVERHEAD]);
460
461 if (hdr->type == ::conf.icmp_type
462 && hdr->code == 255)
463 {
464 // raw sockets deliver the ipv4, but don't expect it on sends
465 // this is slow, but...
466 pkt->skip_hdr (ICMP_OVERHEAD);
467
468 recv_vpn_packet (pkt, si);
469 }
470 }
471 else
472 {
473 // probably ECONNRESET or somesuch
474 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
475 }
476
477 delete pkt;
478 }
479 else
480 {
481 slog (L_ERR,
482 _("FATAL: unknown revents %08x in socket, terminating\n"),
483 revents);
484 exit (EXIT_FAILURE);
485 }
486 }
487 #endif
488
489 void
490 vpn::udpv4_ev (io_watcher &w, short revents)
491 {
492 if (revents & EVENT_READ)
493 {
494 vpn_packet *pkt = new vpn_packet;
495 struct sockaddr_in sa;
496 socklen_t sa_len = sizeof (sa);
497 int len;
498
499 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
500
501 sockinfo si(sa, PROT_UDPv4);
502
503 if (len > 0)
504 {
505 pkt->len = len;
506
507 recv_vpn_packet (pkt, si);
508 }
509 else
510 {
511 // probably ECONNRESET or somesuch
512 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
513 }
514
515 delete pkt;
516 }
517 else
518 {
519 slog (L_ERR,
520 _("FATAL: unknown revents %08x in socket, terminating\n"),
521 revents);
522 exit (EXIT_FAILURE);
523 }
524 }
525
526 void
527 vpn::tap_ev (io_watcher &w, short revents)
528 {
529 if (revents & EVENT_READ)
530 {
531 /* process data */
532 tap_packet *pkt;
533
534 pkt = tap->recv ();
535
536 if (!pkt)
537 return;
538
539 if (pkt->len > 14)
540 {
541 int dst = mac2id (pkt->dst);
542 int src = mac2id (pkt->src);
543
544 if (src != THISNODE->id)
545 {
546 slog (L_ERR, _("FATAL: tap packet not originating on current node received (if-up script not working properly?), exiting."));
547 exit (EXIT_FAILURE);
548 }
549
550 if (dst == THISNODE->id)
551 {
552 slog (L_ERR, _("FATAL: tap packet destined for current node received, exiting."));
553 exit (EXIT_FAILURE);
554 }
555
556 if (dst > conns.size ())
557 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
558 else
559 inject_data_packet (pkt, dst);
560 }
561
562 delete pkt;
563 }
564 else
565 abort ();
566 }
567
568 void
569 vpn::event_cb (time_watcher &w)
570 {
571 if (events)
572 {
573 if (events & EVENT_SHUTDOWN)
574 {
575 slog (L_INFO, _("preparing shutdown..."));
576
577 shutdown_all ();
578 remove_pid (conf.pidfilename);
579 slog (L_INFO, _("terminating"));
580 exit (EXIT_SUCCESS);
581 }
582
583 if (events & EVENT_RECONNECT)
584 {
585 slog (L_INFO, _("forced reconnect"));
586
587 reconnect_all ();
588 }
589
590 events = 0;
591 }
592 }
593
594 void
595 vpn::shutdown_all ()
596 {
597 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
598 (*c)->shutdown ();
599 }
600
601 void
602 vpn::reconnect_all ()
603 {
604 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
605 delete *c;
606
607 conns.clear ();
608
609 connection_init ();
610
611 for (configuration::node_vector::iterator i = conf.nodes.begin ();
612 i != conf.nodes.end (); ++i)
613 {
614 connection *conn = new connection (this, *i);
615 conns.push_back (conn);
616 conn->establish_connection ();
617 }
618 }
619
620 connection *vpn::find_router ()
621 {
622 u32 prio = 1;
623 connection *router = 0;
624
625 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
626 {
627 connection *c = *i;
628
629 if (c->conf->routerprio > prio
630 && c->connectmode == conf_node::C_ALWAYS // so we don't drop the connection if in use
631 && c->ictx && c->octx
632 && c->conf != THISNODE) // redundant, since ictx==octx==0 always on thisnode
633 {
634 prio = c->conf->routerprio;
635 router = c;
636 }
637 }
638
639 return router;
640 }
641
642 void vpn::send_connect_request (int id)
643 {
644 connection *c = find_router ();
645
646 if (c)
647 c->send_connect_request (id);
648 else
649 // no router found, aggressively connect to all routers
650 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
651 if ((*i)->conf->routerprio && (*i)->conf != THISNODE)
652 (*i)->establish_connection ();
653 }
654
655 void
656 connection::dump_status ()
657 {
658 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
659 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
660 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
661 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
662 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
663 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
664 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
665 }
666
667 void
668 vpn::dump_status ()
669 {
670 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
671
672 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
673 (*c)->dump_status ();
674
675 slog (L_NOTICE, _("END status dump"));
676 }
677
678 vpn::vpn (void)
679 : event (this, &vpn::event_cb)
680 , udpv4_ev_watcher (this, &vpn::udpv4_ev)
681 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
682 #if ENABLE_TCP
683 , tcpv4_ev_watcher (this, &vpn::tcpv4_ev)
684 #endif
685 #if ENABLE_ICMP
686 , icmpv4_ev_watcher(this, &vpn::icmpv4_ev)
687 #endif
688 #if ENABLE_DNS
689 , dnsv4_ev_watcher (this, &vpn::dnsv4_ev)
690 #endif
691 , tap_ev_watcher (this, &vpn::tap_ev)
692 {
693 }
694
695 vpn::~vpn ()
696 {
697 }
698