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Revision: 1.2
Committed: Wed Apr 2 05:15:00 2003 UTC (21 years, 1 month ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.1: +195 -16 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 <netinet/in.h>
32 #include <arpa/inet.h>
33 #include <errno.h>
34 #include <time.h>
35 #include <unistd.h>
36
37 #include "pidfile.h"
38
39 #include "connection.h"
40 #include "util.h"
41 #include "vpn.h"
42
43 #if ENABLE_TCP
44 # include <map>
45 # include <unistd.h>
46 # include <fcntl.h>
47 # include <sys/poll.h>
48 #endif
49
50 /////////////////////////////////////////////////////////////////////////////
51
52 const char *vpn::script_if_up ()
53 {
54 // the tunnel device mtu should be the physical mtu - overhead
55 // the tricky part is rounding to the cipher key blocksize
56 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
57 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
58 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
59 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
60
61 char *env;
62 asprintf (&env, "CONFBASE=%s", confbase);
63 putenv (env);
64 asprintf (&env, "NODENAME=%s", THISNODE->nodename);
65 putenv (env);
66 asprintf (&env, "NODEID=%d", THISNODE->id);
67 putenv (env);
68 asprintf (&env, "IFNAME=%s", tap->interface ());
69 putenv (env);
70 asprintf (&env, "MTU=%d", mtu);
71 putenv (env);
72 asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
73 0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
74 THISNODE->id & 0xff);
75 putenv (env);
76
77 return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
78 }
79
80 int
81 vpn::setup ()
82 {
83 udpv4_fd = -1;
84
85 if (THISNODE->protocols & PROT_UDPv4)
86 {
87 udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
88
89 if (udpv4_fd < 0)
90 return -1;
91
92 sockinfo si (THISNODE, PROT_UDPv4);
93
94 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
95 {
96 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
97 exit (1);
98 }
99
100 #ifdef IP_MTU_DISCOVER
101 // this I really consider a linux bug. I am neither connected
102 // nor do I fragment myself. Linux still sets DF and doesn't
103 // fragment for me sometimes.
104 {
105 int oval = IP_PMTUDISC_DONT;
106 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
107 }
108 #endif
109
110 // standard daemon practise...
111 {
112 int oval = 1;
113 setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
114 }
115
116 udpv4_ev_watcher.start (udpv4_fd, POLLIN);
117 }
118
119 ipv4_fd = -1;
120 if (THISNODE->protocols & PROT_IPv4)
121 {
122 ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
123
124 if (ipv4_fd < 0)
125 return -1;
126
127 sockinfo si (THISNODE, PROT_IPv4);
128
129 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
130 {
131 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
132 exit (1);
133 }
134
135 #ifdef IP_MTU_DISCOVER
136 // this I really consider a linux bug. I am neither connected
137 // nor do I fragment myself. Linux still sets DF and doesn't
138 // fragment for me sometimes.
139 {
140 int oval = IP_PMTUDISC_DONT;
141 setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
142 }
143 #endif
144
145 ipv4_ev_watcher.start (ipv4_fd, POLLIN);
146 }
147
148 #if ENABLE_TCP
149 if (THISNODE->protocols & PROT_TCPv4)
150 {
151 tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
152
153 if (tcpv4_fd < 0)
154 return -1;
155
156 sockinfo si (THISNODE, PROT_TCPv4);
157
158 if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
159 {
160 slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
161 exit (1);
162 }
163
164 if (listen (tcpv4_fd, 5))
165 {
166 slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
167 exit (1);
168 }
169
170 // standard daemon practise...
171 {
172 int oval = 1;
173 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
174 }
175
176 tcpv4_accept_watcher.start (tcpv4_fd, POLLIN);
177 }
178 #endif
179
180 tap = new tap_device ();
181 if (!tap) //D this, of course, never catches
182 {
183 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
184 exit (1);
185 }
186
187 run_script (run_script_cb (this, &vpn::script_if_up), true);
188
189 tap_ev_watcher.start (tap->fd, POLLIN);
190
191 reconnect_all ();
192
193 return 0;
194 }
195
196 void
197 vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
198 {
199 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
200 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
201 }
202
203 void
204 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
205 {
206 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
207 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
208 }
209
210 void
211 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
212 {
213 unsigned int src = pkt->src ();
214 unsigned int dst = pkt->dst ();
215
216 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
217 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
218
219 if (src == 0 || src > conns.size ()
220 || dst > conns.size ()
221 || pkt->typ () >= vpn_packet::PT_MAX)
222 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
223 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
224 else
225 {
226 connection *c = conns[src - 1];
227
228 if (dst == 0 && !THISNODE->routerprio)
229 slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
230 c->conf->nodename, (const char *)rsi);
231 else if (dst != 0 && dst != THISNODE->id)
232 // FORWARDING NEEDED ;)
233 slog (L_WARN,
234 _("received frame for node %d ('%s') from %s, but this is node %d ('%s')"),
235 dst, conns[dst - 1]->conf->nodename,
236 (const char *)rsi,
237 THISNODE->id, THISNODE->nodename);
238 else
239 c->recv_vpn_packet (pkt, rsi);
240 }
241 }
242
243 void
244 vpn::udpv4_ev (int fd, short revents)
245 {
246 if (revents & (POLLIN | POLLERR))
247 {
248 vpn_packet *pkt = new vpn_packet;
249 struct sockaddr_in sa;
250 socklen_t sa_len = sizeof (sa);
251 int len;
252
253 len = recvfrom (fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
254
255 sockinfo si(sa);
256
257 if (len > 0)
258 {
259 pkt->len = len;
260
261 recv_vpn_packet (pkt, si);
262 }
263 else
264 {
265 // probably ECONNRESET or somesuch
266 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
267 }
268
269 delete pkt;
270 }
271 else if (revents & POLLHUP)
272 {
273 // this cannot ;) happen on udp sockets
274 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
275 exit (1);
276 }
277 else
278 {
279 slog (L_ERR,
280 _("FATAL: unknown revents %08x in socket, terminating\n"),
281 revents);
282 exit (1);
283 }
284 }
285
286 void
287 vpn::ipv4_ev (int fd, short revents)
288 {
289 if (revents & (POLLIN | POLLERR))
290 {
291 vpn_packet *pkt = new vpn_packet;
292 struct sockaddr_in sa;
293 socklen_t sa_len = sizeof (sa);
294 int len;
295
296 len = recvfrom (fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
297
298 sockinfo si(sa, PROT_IPv4);
299
300 if (len > 0)
301 {
302 pkt->len = len;
303
304 // raw sockets deliver the ipv4, but don't expect it on sends
305 // this is slow, but...
306 pkt->skip_hdr (IP_OVERHEAD);
307
308 recv_vpn_packet (pkt, si);
309 }
310 else
311 {
312 // probably ECONNRESET or somesuch
313 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
314 }
315
316 delete pkt;
317 }
318 else if (revents & POLLHUP)
319 {
320 // this cannot ;) happen on udp sockets
321 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
322 exit (1);
323 }
324 else
325 {
326 slog (L_ERR,
327 _("FATAL: unknown revents %08x in socket, terminating\n"),
328 revents);
329 exit (1);
330 }
331 }
332
333 #if ENABLE_TCP
334
335 struct tcp_info {
336 int fd;
337 bool ok;
338 io_watcher r;
339
340 tcp_info (vpn *v)
341 : r(v, &vpn::tcpv4_ev)
342 {
343 fd = -1;
344 }
345
346 ~tcp_info () { close (fd); }
347 };
348
349 typedef map<sockinfo, tcp_info *> tcp_si_map;
350 typedef map<int, tcp_info *> tcp_fd_map; // unneecssary if iom would be cooler
351 static tcp_si_map tcp_si;
352 static tcp_fd_map tcp_fd;
353
354 void
355 vpn::send_tcpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
356 {
357 tcp_si_map::iterator info = tcp_si.find (si);
358
359 if (info == tcp_si.end ())
360 {
361 // woaw, the first lost packet ;)
362 tcp_info *i = new tcp_info (this);
363
364 i->ok = false;
365 i->fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
366
367 if (i->fd >= 0)
368 {
369 fcntl (i->fd, F_SETFL, O_NONBLOCK);
370
371 if (connect (i->fd, si.sav4 (), si.salenv4 ()) >= 0
372 || errno == EINPROGRESS)
373 {
374 tcp_si.insert (tcp_si_map::value_type (si, i));
375 tcp_fd.insert (tcp_fd_map::value_type (i->fd, i));
376 return;
377 }
378
379 delete i;
380 }
381 }
382 else
383 {
384 tcp_info *i = info->second;
385
386 if (i->ok)
387 {
388 setsockopt (i->fd, SOL_IP, IP_TOS, &tos, sizeof tos);
389
390 if (write (i->fd, (void *)pkt, pkt->len + sizeof (u32)) != pkt->len + sizeof (u32))
391 {
392 // error, close socket, forget it and retry immediately
393 tcp_si.erase (info);
394 tcp_fd.erase (i->fd);
395 delete i;
396
397 // tail recursion is... better than goto(?)
398 send_tcpv4_packet (pkt, si, tos);
399 }
400 }
401 }
402
403 #if 0
404 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
405 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
406 #endif
407 }
408
409 void
410 vpn::tcpv4_accept (int fd, short revents)
411 {
412 if (revents & (POLLIN | POLLERR))
413 {
414 struct sockaddr_in sa;
415 socklen_t sa_len = sizeof (sa);
416 int len;
417
418 fd = accept (fd, (sockaddr *)&sa, &sa_len);
419
420 if (fd >= 0)
421 {
422 fcntl (fd, F_SETFL, O_NONBLOCK);
423
424 sockinfo si(sa, PROT_TCPv4);
425 tcp_info *i = new tcp_info (this);
426
427 i->fd = fd;
428 i->ok = true;
429 i->r.start (fd, POLLIN);
430
431 tcp_si.insert (tcp_si_map::value_type (si, i));
432 tcp_fd.insert (tcp_fd_map::value_type (fd, i));
433 }
434 }
435 }
436
437 void
438 vpn::tcpv4_ev (int fd, short revents)
439 {
440 if (revents & (POLLIN | POLLERR))
441 {
442 tcp_fd_map::iterator info = tcp_fd.find (fd);
443
444 if (info != tcp_fd.end ())
445 {
446 tcp_info *i = info->second;
447
448 if (!i->ok) // not yet established
449 {
450 i->ok = true;
451 fcntl (i->fd, F_SETFL, 0);
452 }
453
454 u32 len;
455
456 if (sizeof (len) == read (fd, &len, sizeof (len)))
457 {
458 slog (L_ERR, "%d bytes received\n", len);
459 }
460
461 //tcp_si.erase (i);
462 tcp_fd.erase (fd);
463 delete i;
464 }
465 }
466 }
467
468 #endif
469
470 void
471 vpn::tap_ev (int fd, short revents)
472 {
473 if (revents & POLLIN)
474 {
475 /* process data */
476 tap_packet *pkt;
477
478 pkt = tap->recv ();
479
480 int dst = mac2id (pkt->dst);
481 int src = mac2id (pkt->src);
482
483 if (src != THISNODE->id)
484 {
485 slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
486 exit (1);
487 }
488
489 if (dst == THISNODE->id)
490 {
491 slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
492 exit (1);
493 }
494
495 if (dst > conns.size ())
496 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
497 else
498 {
499 if (dst)
500 {
501 // unicast
502 if (dst != THISNODE->id)
503 conns[dst - 1]->inject_data_packet (pkt);
504 }
505 else
506 {
507 // broadcast, first check router, then self, then english
508 connection *router = find_router ();
509
510 if (router)
511 router->inject_data_packet (pkt, true);
512 else
513 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
514 if ((*c)->conf != THISNODE)
515 (*c)->inject_data_packet (pkt);
516 }
517 }
518
519 delete pkt;
520 }
521 else if (revents & (POLLHUP | POLLERR))
522 {
523 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
524 exit (1);
525 }
526 else
527 abort ();
528 }
529
530 void
531 vpn::event_cb (tstamp &ts)
532 {
533 if (events)
534 {
535 if (events & EVENT_SHUTDOWN)
536 {
537 slog (L_INFO, _("preparing shutdown..."));
538
539 shutdown_all ();
540
541 remove_pid (pidfilename);
542
543 slog (L_INFO, _("terminating"));
544
545 exit (0);
546 }
547
548 if (events & EVENT_RECONNECT)
549 {
550 slog (L_INFO, _("forced reconnect"));
551
552 reconnect_all ();
553 }
554
555 events = 0;
556 }
557
558 ts = TSTAMP_CANCEL;
559 }
560
561 void
562 vpn::shutdown_all ()
563 {
564 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
565 (*c)->shutdown ();
566 }
567
568 void
569 vpn::reconnect_all ()
570 {
571 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
572 delete *c;
573
574 conns.clear ();
575
576 connection_init ();
577
578 for (configuration::node_vector::iterator i = conf.nodes.begin ();
579 i != conf.nodes.end (); ++i)
580 {
581 connection *conn = new connection (this);
582
583 conn->conf = *i;
584 conns.push_back (conn);
585
586 conn->establish_connection ();
587 }
588 }
589
590 connection *vpn::find_router ()
591 {
592 u32 prio = 0;
593 connection *router = 0;
594
595 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
596 {
597 connection *c = *i;
598
599 if (c->conf->routerprio > prio
600 && c->connectmode == conf_node::C_ALWAYS
601 && c->conf != THISNODE
602 && c->ictx && c->octx)
603 {
604 prio = c->conf->routerprio;
605 router = c;
606 }
607 }
608
609 return router;
610 }
611
612 void vpn::connect_request (int id)
613 {
614 connection *c = find_router ();
615
616 if (c)
617 c->connect_request (id);
618 //else // does not work, because all others must connect to the same router
619 // // no router found, aggressively connect to all routers
620 // for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
621 // if ((*i)->conf->routerprio)
622 // (*i)->establish_connection ();
623 }
624
625 void
626 connection::dump_status ()
627 {
628 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
629 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
630 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
631 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
632 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
633 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
634 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
635 }
636
637 void
638 vpn::dump_status ()
639 {
640 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
641
642 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
643 (*c)->dump_status ();
644
645 slog (L_NOTICE, _("END status dump"));
646 }
647
648 vpn::vpn (void)
649 : event(this, &vpn::event_cb)
650 , udpv4_ev_watcher(this, &vpn::udpv4_ev)
651 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
652 , tap_ev_watcher (this, &vpn::tap_ev)
653 #if ENABLE_TCP
654 , tcpv4_accept_watcher(this, &vpn::tcpv4_accept)
655 #endif
656 {
657 }
658
659 vpn::~vpn ()
660 {
661 }
662