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Revision: 1.5
Committed: Sat Apr 5 02:32:40 2003 UTC (21 years, 1 month ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.4: +30 -185 lines
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File Contents

# User Rev Content
1 pcg 1.1 /*
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 pcg 1.2 const char *vpn::script_if_up ()
46 pcg 1.1 {
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     udpv4_fd = -1;
77    
78     if (THISNODE->protocols & PROT_UDPv4)
79     {
80     udpv4_fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP);
81    
82     if (udpv4_fd < 0)
83     return -1;
84    
85 pcg 1.3 // standard daemon practise...
86     {
87     int oval = 1;
88     setsockopt (udpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
89     }
90    
91 pcg 1.2 sockinfo si (THISNODE, PROT_UDPv4);
92    
93 pcg 1.1 if (bind (udpv4_fd, si.sav4 (), si.salenv4 ()))
94     {
95 pcg 1.2 slog (L_ERR, _("can't bind udpv4 on %s: %s"), (const char *)si, strerror (errno));
96 pcg 1.1 exit (1);
97     }
98    
99     #ifdef IP_MTU_DISCOVER
100     // this I really consider a linux bug. I am neither connected
101     // nor do I fragment myself. Linux still sets DF and doesn't
102     // fragment for me sometimes.
103     {
104     int oval = IP_PMTUDISC_DONT;
105     setsockopt (udpv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
106     }
107     #endif
108    
109     udpv4_ev_watcher.start (udpv4_fd, POLLIN);
110     }
111    
112     ipv4_fd = -1;
113     if (THISNODE->protocols & PROT_IPv4)
114     {
115     ipv4_fd = socket (PF_INET, SOCK_RAW, ::conf.ip_proto);
116    
117     if (ipv4_fd < 0)
118     return -1;
119    
120 pcg 1.2 sockinfo si (THISNODE, PROT_IPv4);
121    
122 pcg 1.1 if (bind (ipv4_fd, si.sav4 (), si.salenv4 ()))
123     {
124 pcg 1.2 slog (L_ERR, _("can't bind ipv4 socket on %s: %s"), (const char *)si, strerror (errno));
125 pcg 1.1 exit (1);
126     }
127    
128     #ifdef 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 (ipv4_fd, SOL_IP, IP_MTU_DISCOVER, &oval, sizeof oval);
135     }
136     #endif
137    
138     ipv4_ev_watcher.start (ipv4_fd, POLLIN);
139     }
140    
141 pcg 1.2 #if ENABLE_TCP
142     if (THISNODE->protocols & PROT_TCPv4)
143     {
144     tcpv4_fd = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
145    
146     if (tcpv4_fd < 0)
147     return -1;
148    
149 pcg 1.3 // standard daemon practise...
150     {
151     int oval = 1;
152     setsockopt (tcpv4_fd, SOL_SOCKET, SO_REUSEADDR, &oval, sizeof oval);
153     }
154    
155 pcg 1.2 sockinfo si (THISNODE, PROT_TCPv4);
156    
157     if (bind (tcpv4_fd, si.sav4 (), si.salenv4 ()))
158     {
159     slog (L_ERR, _("can't bind tcpv4 on %s: %s"), (const char *)si, strerror (errno));
160     exit (1);
161     }
162    
163     if (listen (tcpv4_fd, 5))
164     {
165     slog (L_ERR, _("can't listen tcpv4 on %s: %s"), (const char *)si, strerror (errno));
166     exit (1);
167     }
168    
169 pcg 1.3 tcpv4_ev_watcher.start (tcpv4_fd, POLLIN);
170 pcg 1.2 }
171     #endif
172    
173 pcg 1.1 tap = new tap_device ();
174     if (!tap) //D this, of course, never catches
175     {
176     slog (L_ERR, _("cannot create network interface '%s'"), conf.ifname);
177     exit (1);
178     }
179    
180     run_script (run_script_cb (this, &vpn::script_if_up), true);
181    
182     tap_ev_watcher.start (tap->fd, POLLIN);
183    
184     reconnect_all ();
185    
186     return 0;
187     }
188    
189 pcg 1.5 // send a vpn packet out to other hosts
190     void
191     vpn::send_vpn_packet (vpn_packet *pkt, const sockinfo &si, int tos)
192     {
193     switch (si.prot)
194     {
195     case PROT_IPv4:
196     send_ipv4_packet (pkt, si, tos);
197     break;
198    
199     case PROT_UDPv4:
200     send_udpv4_packet (pkt, si, tos);
201     break;
202    
203     #if ENABLE_TCP
204     case PROT_TCPv4:
205     send_tcpv4_packet (pkt, si, tos);
206     break;
207     #endif
208    
209     default:
210     slog (L_CRIT, _("%s: FATAL: trying to send packet with unsupported protocol"), (const char *)si);
211     abort ();
212     }
213     }
214    
215 pcg 1.1 void
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    
222     void
223     vpn::send_udpv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
224     {
225     setsockopt (udpv4_fd, SOL_IP, IP_TOS, &tos, sizeof tos);
226     sendto (udpv4_fd, &((*pkt)[0]), pkt->len, 0, si.sav4 (), si.salenv4 ());
227     }
228    
229     void
230     vpn::recv_vpn_packet (vpn_packet *pkt, const sockinfo &rsi)
231     {
232     unsigned int src = pkt->src ();
233     unsigned int dst = pkt->dst ();
234    
235     slog (L_NOISE, _("<<?/%s received possible vpn packet type %d from %d to %d, length %d"),
236     (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst (), pkt->len);
237    
238     if (src == 0 || src > conns.size ()
239     || dst > conns.size ()
240     || pkt->typ () >= vpn_packet::PT_MAX)
241     slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
242     (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
243     else
244     {
245     connection *c = conns[src - 1];
246    
247     if (dst == 0 && !THISNODE->routerprio)
248     slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
249     c->conf->nodename, (const char *)rsi);
250     else if (dst != 0 && dst != THISNODE->id)
251     // FORWARDING NEEDED ;)
252     slog (L_WARN,
253     _("received frame for node %d ('%s') from %s, but this is node %d ('%s')"),
254     dst, conns[dst - 1]->conf->nodename,
255     (const char *)rsi,
256     THISNODE->id, THISNODE->nodename);
257     else
258     c->recv_vpn_packet (pkt, rsi);
259     }
260     }
261    
262     void
263 pcg 1.3 vpn::udpv4_ev (io_watcher &w, short revents)
264 pcg 1.1 {
265     if (revents & (POLLIN | POLLERR))
266     {
267     vpn_packet *pkt = new vpn_packet;
268     struct sockaddr_in sa;
269     socklen_t sa_len = sizeof (sa);
270     int len;
271    
272 pcg 1.5 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
273 pcg 1.1
274 pcg 1.5 sockinfo si(sa, PROT_UDPv4);
275 pcg 1.1
276     if (len > 0)
277     {
278     pkt->len = len;
279    
280     recv_vpn_packet (pkt, si);
281     }
282     else
283     {
284     // probably ECONNRESET or somesuch
285 pcg 1.5 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
286 pcg 1.1 }
287    
288     delete pkt;
289     }
290     else if (revents & POLLHUP)
291     {
292     // this cannot ;) happen on udp sockets
293     slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
294     exit (1);
295     }
296     else
297     {
298     slog (L_ERR,
299     _("FATAL: unknown revents %08x in socket, terminating\n"),
300     revents);
301     exit (1);
302     }
303     }
304    
305     void
306 pcg 1.3 vpn::ipv4_ev (io_watcher &w, short revents)
307 pcg 1.1 {
308     if (revents & (POLLIN | POLLERR))
309     {
310     vpn_packet *pkt = new vpn_packet;
311     struct sockaddr_in sa;
312     socklen_t sa_len = sizeof (sa);
313     int len;
314    
315 pcg 1.5 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
316 pcg 1.1
317     sockinfo si(sa, PROT_IPv4);
318    
319     if (len > 0)
320     {
321     pkt->len = len;
322    
323     // raw sockets deliver the ipv4, but don't expect it on sends
324     // this is slow, but...
325     pkt->skip_hdr (IP_OVERHEAD);
326    
327     recv_vpn_packet (pkt, si);
328     }
329     else
330     {
331     // probably ECONNRESET or somesuch
332     slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
333     }
334    
335     delete pkt;
336     }
337     else if (revents & POLLHUP)
338     {
339     // this cannot ;) happen on udp sockets
340     slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
341     exit (1);
342     }
343     else
344     {
345     slog (L_ERR,
346     _("FATAL: unknown revents %08x in socket, terminating\n"),
347     revents);
348     exit (1);
349     }
350     }
351 pcg 1.2
352     void
353 pcg 1.3 vpn::tap_ev (io_watcher &w, short revents)
354 pcg 1.1 {
355     if (revents & POLLIN)
356     {
357     /* process data */
358     tap_packet *pkt;
359    
360     pkt = tap->recv ();
361    
362     int dst = mac2id (pkt->dst);
363     int src = mac2id (pkt->src);
364    
365     if (src != THISNODE->id)
366     {
367     slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
368     exit (1);
369     }
370    
371     if (dst == THISNODE->id)
372     {
373     slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
374     exit (1);
375     }
376    
377     if (dst > conns.size ())
378     slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
379     else
380     {
381     if (dst)
382     {
383     // unicast
384     if (dst != THISNODE->id)
385     conns[dst - 1]->inject_data_packet (pkt);
386     }
387     else
388     {
389     // broadcast, first check router, then self, then english
390     connection *router = find_router ();
391    
392     if (router)
393     router->inject_data_packet (pkt, true);
394     else
395     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
396     if ((*c)->conf != THISNODE)
397     (*c)->inject_data_packet (pkt);
398     }
399     }
400    
401     delete pkt;
402     }
403     else if (revents & (POLLHUP | POLLERR))
404     {
405     slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
406     exit (1);
407     }
408     else
409     abort ();
410     }
411    
412     void
413 pcg 1.3 vpn::event_cb (time_watcher &w)
414 pcg 1.1 {
415     if (events)
416     {
417     if (events & EVENT_SHUTDOWN)
418     {
419     slog (L_INFO, _("preparing shutdown..."));
420    
421     shutdown_all ();
422    
423     remove_pid (pidfilename);
424    
425     slog (L_INFO, _("terminating"));
426    
427     exit (0);
428     }
429    
430     if (events & EVENT_RECONNECT)
431     {
432     slog (L_INFO, _("forced reconnect"));
433    
434     reconnect_all ();
435     }
436    
437     events = 0;
438     }
439    
440 pcg 1.3 w.at = TSTAMP_CANCEL;
441 pcg 1.1 }
442    
443     void
444     vpn::shutdown_all ()
445     {
446     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
447     (*c)->shutdown ();
448     }
449    
450     void
451     vpn::reconnect_all ()
452     {
453     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
454     delete *c;
455    
456     conns.clear ();
457    
458     connection_init ();
459    
460     for (configuration::node_vector::iterator i = conf.nodes.begin ();
461     i != conf.nodes.end (); ++i)
462     {
463     connection *conn = new connection (this);
464    
465     conn->conf = *i;
466     conns.push_back (conn);
467    
468     conn->establish_connection ();
469     }
470     }
471    
472     connection *vpn::find_router ()
473     {
474     u32 prio = 0;
475     connection *router = 0;
476    
477     for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
478     {
479     connection *c = *i;
480    
481     if (c->conf->routerprio > prio
482     && c->connectmode == conf_node::C_ALWAYS
483     && c->conf != THISNODE
484     && c->ictx && c->octx)
485     {
486     prio = c->conf->routerprio;
487     router = c;
488     }
489     }
490    
491     return router;
492     }
493    
494     void vpn::connect_request (int id)
495     {
496     connection *c = find_router ();
497    
498     if (c)
499     c->connect_request (id);
500     //else // does not work, because all others must connect to the same router
501     // // no router found, aggressively connect to all routers
502     // for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
503     // if ((*i)->conf->routerprio)
504     // (*i)->establish_connection ();
505     }
506    
507     void
508     connection::dump_status ()
509     {
510     slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
511     slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
512     connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
513     slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
514     (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
515     slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
516     (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
517     }
518    
519     void
520     vpn::dump_status ()
521     {
522     slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
523    
524     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
525     (*c)->dump_status ();
526    
527     slog (L_NOTICE, _("END status dump"));
528     }
529    
530     vpn::vpn (void)
531 pcg 1.2 : event(this, &vpn::event_cb)
532     , udpv4_ev_watcher(this, &vpn::udpv4_ev)
533     , ipv4_ev_watcher (this, &vpn::ipv4_ev)
534     , tap_ev_watcher (this, &vpn::tap_ev)
535     #if ENABLE_TCP
536 pcg 1.3 , tcpv4_ev_watcher(this, &vpn::tcpv4_ev)
537 pcg 1.2 #endif
538 pcg 1.1 {
539     }
540    
541     vpn::~vpn ()
542     {
543     }
544