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Revision: 1.6
Committed: Sun Apr 6 04:17:36 2003 UTC (21 years, 2 months ago) by pcg
Content type: text/plain
Branch: MAIN
Changes since 1.5: +13 -6 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 pcg 1.6 else if (dst > conns.size ())
244     slog (L_WARN, _("(%s): received corrupted packet type %d (src %d, dst %d)"),
245     (const char *)rsi, pkt->typ (), pkt->src (), pkt->dst ());
246 pcg 1.1 else
247     {
248     connection *c = conns[src - 1];
249    
250     if (dst == 0 && !THISNODE->routerprio)
251     slog (L_WARN, _("%s(%s): received broadcast, but we are no router"),
252     c->conf->nodename, (const char *)rsi);
253     else if (dst != 0 && dst != THISNODE->id)
254 pcg 1.6 {
255     if (THISNODE->routerprio)
256     // the tos setting gets lost here. who cares.
257     conns[dst - 1]->inject_vpn_packet (pkt);
258     else
259     slog (L_WARN,
260     _("%s(%s): forwarding request (=> %s), but we are no router"),
261     c->conf->nodename, (const char *)rsi,
262     conns[dst - 1]->conf->nodename);
263     }
264 pcg 1.1 else
265     c->recv_vpn_packet (pkt, rsi);
266     }
267     }
268    
269     void
270 pcg 1.3 vpn::udpv4_ev (io_watcher &w, short revents)
271 pcg 1.1 {
272     if (revents & (POLLIN | POLLERR))
273     {
274     vpn_packet *pkt = new vpn_packet;
275     struct sockaddr_in sa;
276     socklen_t sa_len = sizeof (sa);
277     int len;
278    
279 pcg 1.5 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
280 pcg 1.1
281 pcg 1.5 sockinfo si(sa, PROT_UDPv4);
282 pcg 1.1
283     if (len > 0)
284     {
285     pkt->len = len;
286    
287     recv_vpn_packet (pkt, si);
288     }
289     else
290     {
291     // probably ECONNRESET or somesuch
292 pcg 1.5 slog (L_DEBUG, _("%s: fd %d, %s"), (const char *)si, w.fd, strerror (errno));
293 pcg 1.1 }
294    
295     delete pkt;
296     }
297     else if (revents & POLLHUP)
298     {
299     // this cannot ;) happen on udp sockets
300     slog (L_ERR, _("FATAL: POLLHUP on udp v4 fd, terminating."));
301     exit (1);
302     }
303     else
304     {
305     slog (L_ERR,
306     _("FATAL: unknown revents %08x in socket, terminating\n"),
307     revents);
308     exit (1);
309     }
310     }
311    
312     void
313 pcg 1.3 vpn::ipv4_ev (io_watcher &w, short revents)
314 pcg 1.1 {
315     if (revents & (POLLIN | POLLERR))
316     {
317     vpn_packet *pkt = new vpn_packet;
318     struct sockaddr_in sa;
319     socklen_t sa_len = sizeof (sa);
320     int len;
321    
322 pcg 1.5 len = recvfrom (w.fd, &((*pkt)[0]), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
323 pcg 1.1
324     sockinfo si(sa, PROT_IPv4);
325    
326     if (len > 0)
327     {
328     pkt->len = len;
329    
330     // raw sockets deliver the ipv4, but don't expect it on sends
331     // this is slow, but...
332     pkt->skip_hdr (IP_OVERHEAD);
333    
334     recv_vpn_packet (pkt, si);
335     }
336     else
337     {
338     // probably ECONNRESET or somesuch
339     slog (L_DEBUG, _("%s: %s"), (const char *)si, strerror (errno));
340     }
341    
342     delete pkt;
343     }
344     else if (revents & POLLHUP)
345     {
346     // this cannot ;) happen on udp sockets
347     slog (L_ERR, _("FATAL: POLLHUP on ipv4 fd, terminating."));
348     exit (1);
349     }
350     else
351     {
352     slog (L_ERR,
353     _("FATAL: unknown revents %08x in socket, terminating\n"),
354     revents);
355     exit (1);
356     }
357     }
358 pcg 1.2
359     void
360 pcg 1.3 vpn::tap_ev (io_watcher &w, short revents)
361 pcg 1.1 {
362     if (revents & POLLIN)
363     {
364     /* process data */
365     tap_packet *pkt;
366    
367     pkt = tap->recv ();
368    
369     int dst = mac2id (pkt->dst);
370     int src = mac2id (pkt->src);
371    
372     if (src != THISNODE->id)
373     {
374     slog (L_ERR, _("FATAL: tap packet not originating on current node received, terminating."));
375     exit (1);
376     }
377    
378     if (dst == THISNODE->id)
379     {
380     slog (L_ERR, _("FATAL: tap packet destined for current node received, terminating."));
381     exit (1);
382     }
383    
384     if (dst > conns.size ())
385     slog (L_ERR, _("tap packet for unknown node %d received, ignoring."), dst);
386     else
387     {
388     if (dst)
389     {
390     // unicast
391     if (dst != THISNODE->id)
392     conns[dst - 1]->inject_data_packet (pkt);
393     }
394     else
395     {
396     // broadcast, first check router, then self, then english
397     connection *router = find_router ();
398    
399     if (router)
400     router->inject_data_packet (pkt, true);
401     else
402     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
403     if ((*c)->conf != THISNODE)
404     (*c)->inject_data_packet (pkt);
405     }
406     }
407    
408     delete pkt;
409     }
410     else if (revents & (POLLHUP | POLLERR))
411     {
412     slog (L_ERR, _("FATAL: POLLHUP or POLLERR on network device fd, terminating."));
413     exit (1);
414     }
415     else
416     abort ();
417     }
418    
419     void
420 pcg 1.3 vpn::event_cb (time_watcher &w)
421 pcg 1.1 {
422     if (events)
423     {
424     if (events & EVENT_SHUTDOWN)
425     {
426     slog (L_INFO, _("preparing shutdown..."));
427    
428     shutdown_all ();
429    
430     remove_pid (pidfilename);
431    
432     slog (L_INFO, _("terminating"));
433    
434     exit (0);
435     }
436    
437     if (events & EVENT_RECONNECT)
438     {
439     slog (L_INFO, _("forced reconnect"));
440    
441     reconnect_all ();
442     }
443    
444     events = 0;
445     }
446    
447 pcg 1.3 w.at = TSTAMP_CANCEL;
448 pcg 1.1 }
449    
450     void
451     vpn::shutdown_all ()
452     {
453     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
454     (*c)->shutdown ();
455     }
456    
457     void
458     vpn::reconnect_all ()
459     {
460     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
461     delete *c;
462    
463     conns.clear ();
464    
465     connection_init ();
466    
467     for (configuration::node_vector::iterator i = conf.nodes.begin ();
468     i != conf.nodes.end (); ++i)
469     {
470     connection *conn = new connection (this);
471    
472     conn->conf = *i;
473     conns.push_back (conn);
474    
475     conn->establish_connection ();
476     }
477     }
478    
479     connection *vpn::find_router ()
480     {
481     u32 prio = 0;
482     connection *router = 0;
483    
484     for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
485     {
486     connection *c = *i;
487    
488     if (c->conf->routerprio > prio
489     && c->connectmode == conf_node::C_ALWAYS
490     && c->conf != THISNODE
491     && c->ictx && c->octx)
492     {
493     prio = c->conf->routerprio;
494     router = c;
495     }
496     }
497    
498     return router;
499     }
500    
501     void vpn::connect_request (int id)
502     {
503     connection *c = find_router ();
504    
505     if (c)
506     c->connect_request (id);
507     //else // does not work, because all others must connect to the same router
508     // // no router found, aggressively connect to all routers
509     // for (conns_vector::iterator i = conns.begin (); i != conns.end (); ++i)
510     // if ((*i)->conf->routerprio)
511     // (*i)->establish_connection ();
512     }
513    
514     void
515     connection::dump_status ()
516     {
517     slog (L_NOTICE, _("node %s (id %d)"), conf->nodename, conf->id);
518     slog (L_NOTICE, _(" connectmode %d (%d) / sockaddr %s / minor %d"),
519     connectmode, conf->connectmode, (const char *)si, (int)prot_minor);
520     slog (L_NOTICE, _(" ictx/octx %08lx/%08lx / oseqno %d / retry_cnt %d"),
521     (long)ictx, (long)octx, (int)oseqno, (int)retry_cnt);
522     slog (L_NOTICE, _(" establish_conn %ld / rekey %ld / keepalive %ld"),
523     (long)(establish_connection.at), (long)(rekey.at), (long)(keepalive.at));
524     }
525    
526     void
527     vpn::dump_status ()
528     {
529     slog (L_NOTICE, _("BEGIN status dump (%ld)"), (long)NOW);
530    
531     for (conns_vector::iterator c = conns.begin (); c != conns.end (); ++c)
532     (*c)->dump_status ();
533    
534     slog (L_NOTICE, _("END status dump"));
535     }
536    
537     vpn::vpn (void)
538 pcg 1.2 : event(this, &vpn::event_cb)
539     , udpv4_ev_watcher(this, &vpn::udpv4_ev)
540     , ipv4_ev_watcher (this, &vpn::ipv4_ev)
541     , tap_ev_watcher (this, &vpn::tap_ev)
542     #if ENABLE_TCP
543 pcg 1.3 , tcpv4_ev_watcher(this, &vpn::tcpv4_ev)
544 pcg 1.2 #endif
545 pcg 1.1 {
546     }
547    
548     vpn::~vpn ()
549     {
550     }
551