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/cvs/gvpe/src/vpn.C
Revision: 1.8
Committed: Mon Apr 7 01:28:56 2003 UTC (21 years, 1 month ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.7: +28 -25 lines
Log Message:
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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 /////////////////////////////////////////////////////////////////////////////
44
45 const char *vpn::script_if_up ()
46 {
47 // the tunnel device mtu should be the physical mtu - overhead
48 // the tricky part is rounding to the cipher key blocksize
49 int mtu = conf.mtu - ETH_OVERHEAD - VPE_OVERHEAD - MAX_OVERHEAD;
50 mtu += ETH_OVERHEAD - 6 - 6; // now we have the data portion
51 mtu -= mtu % EVP_CIPHER_block_size (CIPHER); // round
52 mtu -= ETH_OVERHEAD - 6 - 6; // and get interface mtu again
53
54 char *env;
55 asprintf (&env, "CONFBASE=%s", confbase);
56 putenv (env);
57 asprintf (&env, "NODENAME=%s", THISNODE->nodename);
58 putenv (env);
59 asprintf (&env, "NODEID=%d", THISNODE->id);
60 putenv (env);
61 asprintf (&env, "IFNAME=%s", tap->interface ());
62 putenv (env);
63 asprintf (&env, "MTU=%d", mtu);
64 putenv (env);
65 asprintf (&env, "MAC=%02x:%02x:%02x:%02x:%02x:%02x",
66 0xfe, 0xfd, 0x80, 0x00, THISNODE->id >> 8,
67 THISNODE->id & 0xff);
68 putenv (env);
69
70 return ::conf.script_if_up ? ::conf.script_if_up : "if-up";
71 }
72
73 int
74 vpn::setup ()
75 {
76 ipv4_fd = -1;
77
78 if (THISNODE->protocols & PROT_IPv4 && ::conf.ip_proto)
79 {
80 ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
81
82 if (ipv4_fd < 0)
83 return -1;
84
85 sockinfo si (THISNODE, PROT_IPv4);
86
87 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
88 {
89 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
90 exit (1);
91 }
92
93 #ifdef IP_MTU_DISCOVER
94 // this I really consider a linux bug. I am neither connected
95 // nor do I fragment myself. Linux still sets DF and doesn't
96 // fragment for me sometimes.
97 {
98 int oval = IP_PMTUDISC_DONT;
99 setsockopt (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
100 }
101 #endif
102
103 ipv4_ev_watcher.start (ipv4_fd, POLLIN);
104 }
105
106 udpv4_fd = -1;
107
108 if (THISNODE->protocols & PROT_UDPv4 && THISNODE->udp_port)
109 {
110 udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
111
112 if (udpv4_fd < 0)
113 return -1;
114
115 // standard daemon practise...
116 {
117 int oval = 1;
118 setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
119 }
120
121 sockinfo si (THISNODE, PROT_UDPv4);
122
123 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
124 {
125 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
126 exit (1);
127 }
128
129 #ifdef IP_MTU_DISCOVER
130 // this I really consider a linux bug. I am neither connected
131 // nor do I fragment myself. Linux still sets DF and doesn't
132 // fragment for me sometimes.
133 {
134 int oval = IP_PMTUDISC_DONT;
135 setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
136 }
137 #endif
138
139 udpv4_ev_watcher.start (udpv4_fd, POLLIN);
140 }
141
142 tcpv4_fd = -1;
143
144 #if ENABLE_TCP
145 if (THISNODE->protocols & PROT_TCPv4 && THISNODE->tcp_port)
146 {
147 tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
148
149 if (tcpv4_fd < 0)
150 return -1;
151
152 // standard daemon practise...
153 {
154 int oval = 1;
155 setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
156 }
157
158 sockinfo si (THISNODE, PROT_TCPv4);
159
160 if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
161 {
162 slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
163 exit (1);
164 }
165
166 if (listen (tcpv4_fd, 5))
167 {
168 slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
169 exit (1);
170 }
171
172 tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
173 }
174 #endif
175
176 tap = new tap_device ();
177 if (!tap) //D this, of course, never catches
178 {
179 slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
180 exit (1);
181 }
182
183 run_script (run_script_cb (this, &vpn::script_if_up), true);
184
185 tap_ev_watcher.start (tap->fd, POLLIN);
186
187 reconnect_all ();
188
189 return 0;
190 }
191
192 // send a vpn packet out to other hosts
193 bool
194 vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
195 {
196 switch (si.prot)
197 {
198 case PROT_IPv4:
199 return send_ipv4_packet (pkt, si, tos);
200
201 case PROT_UDPv4:
202 return send_udpv4_packet (pkt, si, tos);
203
204 #if ENABLE_TCP
205 case PROT_TCPv4:
206 return send_tcpv4_packet (pkt, si, tos);
207 #endif
208
209 default:
210 slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
211 return false;
212 }
213 }
214
215 bool
216 vpn::send_ipv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
217 {
218 setsockopt (ipv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
219 sendto (ipv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
220
221 return true;
222 }
223
224 bool
225 vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
226 {
227 setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
228 sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
229
230 return true;
231 }
232
233 void
234 vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
235 {
236 unsigned int src = pkt->src ();
237 unsigned int dst = pkt->dst ();
238
239 slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
240 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
241
242 if (src == 0 || src > conns.size ()
243 || dst > conns.size ()
244 || pkt->typ () >= vpn_packet::PT_MAX)
245 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
246 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
247 else if (dst > conns.size ())
248 slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
249 (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
250 else
251 {
252 connection *c = conns[src - 1];
253
254 if (dst == 0 && !THISNODE->routerprio)
255 slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
256 c->conf->nodename, (const char *)rsi);
257 else if (dst != 0 && dst != THISNODE->id)
258 {
259 if (THISNODE->routerprio)
260 // the tos setting gets lost here. who cares.
261 conns[dst - 1]->inject_vpn_packet (pkt);
262 else
263 slog (L_WARN,
264 _("%s(%s): forwarding request (=> %s), but we are no router"),
265 c->conf->nodename, (const char *)rsi,
266 conns[dst - 1]->conf->nodename);
267 }
268 else
269 c->recv_vpn_packet (pkt, rsi);
270 }
271 }
272
273 void
274 vpn::udpv4_ev (io_watcher &w, short revents)
275 {
276 if (revents & (POLLIN | POLLERR))
277 {
278 vpn_packet *pkt = new vpn_packet;
279 struct sockaddr_in sa;
280 socklen_t sa_len = sizeof (sa);
281 int len;
282
283 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
284
285 sockinfo si(sa, PROT_UDPv4);
286
287 if (len > 0)
288 {
289 pkt->len = len;
290
291 recv_vpn_packet (pkt, si);
292 }
293 else
294 {
295 // probably ECONNRESET or somesuch
296 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
297 }
298
299 delete pkt;
300 }
301 else if (revents & POLLHUP)
302 {
303 // this cannot ;) happen on udp sockets
304 slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
305 exit (1);
306 }
307 else
308 {
309 slog (L_ERR,
310 _("FATAL: unknown revents %08x in socket, terminating\n"),
311 revents);
312 exit (1);
313 }
314 }
315
316 void
317 vpn::ipv4_ev (io_watcher &w, short revents)
318 {
319 if (revents & (POLLIN | POLLERR))
320 {
321 vpn_packet *pkt = new vpn_packet;
322 struct sockaddr_in sa;
323 socklen_t sa_len = sizeof (sa);
324 int len;
325
326 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
327
328 sockinfo si(sa, PROT_IPv4);
329
330 if (len > 0)
331 {
332 pkt->len = len;
333
334 // raw sockets deliver the ipv4, but don't expect it on sends
335 // this is slow, but...
336 pkt->skip_hdr (IP_OVERHEAD);
337
338 recv_vpn_packet (pkt, si);
339 }
340 else
341 {
342 // probably ECONNRESET or somesuch
343 slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
344 }
345
346 delete pkt;
347 }
348 else if (revents & POLLHUP)
349 {
350 // this cannot ;) happen on udp sockets
351 slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
352 exit (1);
353 }
354 else
355 {
356 slog (L_ERR,
357 _("FATAL: unknown revents %08x in socket, terminating\n"),
358 revents);
359 exit (1);
360 }
361 }
362
363 void
364 vpn::tap_ev (io_watcher &w, short revents)
365 {
366 if (revents & POLLIN)
367 {
368 /* process data */
369 tap_packet *pkt;
370
371 pkt = tap->recv ();
372
373 int dst = mac2id (pkt->dst);
374 int src = mac2id (pkt->src);
375
376 if (src != THISNODE->id)
377 {
378 slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
379 exit (1);
380 }
381
382 if (dst == THISNODE->id)
383 {
384 slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
385 exit (1);
386 }
387
388 if (dst > conns.size ())
389 slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
390 else
391 {
392 if (dst)
393 {
394 // unicast
395 if (dst != THISNODE->id)
396 conns[dst - 1]->inject_data_packet (pkt);
397 }
398 else
399 {
400 // broadcast, first check router, then self, then english
401 connection *router = find_router ();
402
403 if (router)
404 router->inject_data_packet (pkt, true);
405 else
406 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
407 if ((*c)->conf != THISNODE)
408 (*c)->inject_data_packet (pkt);
409 }
410 }
411
412 delete pkt;
413 }
414 else if (revents & (POLLHUP | POLLERR))
415 {
416 slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
417 exit (1);
418 }
419 else
420 abort ();
421 }
422
423 void
424 vpn::event_cb (time_watcher &w)
425 {
426 if (events)
427 {
428 if (events & EVENT_SHUTDOWN)
429 {
430 slog (L_INFO, _("preparing shutdown..."));
431
432 shutdown_all ();
433
434 remove_pid (pidfilename);
435
436 slog (L_INFO, _("terminating"));
437
438 exit (0);
439 }
440
441 if (events & EVENT_RECONNECT)
442 {
443 slog (L_INFO, _("forced reconnect"));
444
445 reconnect_all ();
446 }
447
448 events = 0;
449 }
450
451 w.at = TSTAMP_CANCEL;
452 }
453
454 void
455 vpn::shutdown_all ()
456 {
457 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
458 (*c)->shutdown ();
459 }
460
461 void
462 vpn::reconnect_all ()
463 {
464 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
465 delete *c;
466
467 conns.clear ();
468
469 connection_init ();
470
471 for (configuration::node_vector::iterator i = conf.nodes.begin ();
472 i != conf.nodes.end (); ++i)
473 {
474 connection *conn = new connection (this);
475
476 conn->conf = *i;
477 conns.push_back (conn);
478
479 conn->establish_connection ();
480 }
481 }
482
483 connection *vpn::find_router ()
484 {
485 u32 prio = 0;
486 connection *router = 0;
487
488 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
489 {
490 connection *c = *i;
491
492 if (c->conf->routerprio > prio
493 && c->connectmode == conf_node::C_ALWAYS
494 && c->conf != THISNODE
495 && c->ictx && c->octx)
496 {
497 prio = c->conf->routerprio;
498 router = c;
499 }
500 }
501
502 return router;
503 }
504
505 void vpn::send_connect_request (int id)
506 {
507 connection *c = find_router ();
508
509 if (c)
510 c->send_connect_request (id);
511 else
512 // no router found, aggressively connect to all routers
513 for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
514 if ((*i)->conf->routerprio)
515 (*i)->establish_connection ();
516 }
517
518 void
519 connection::dump_status ()
520 {
521 slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
522 slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
523 connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
524 slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
525 (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
526 slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
527 (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
528 }
529
530 void
531 vpn::dump_status ()
532 {
533 slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
534
535 for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
536 (*c)->dump_status ();
537
538 slog (L_NOTICE, _("END status dump"));
539 }
540
541 vpn::vpn (void)
542 : event(this, &vpn::event_cb)
543 , udpv4_ev_watcher(this, &vpn::udpv4_ev)
544 , ipv4_ev_watcher (this, &vpn::ipv4_ev)
545 , tap_ev_watcher (this, &vpn::tap_ev)
546 #if ENABLE_TCP
547 , tcpv4_ev_watcher(this, &vpn::tcpv4_ev)
548 #endif
549 {
550 }
551
552 vpn::~vpn ()
553 {
554 }
555