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Stop rebinding when all IAs are lost
[project/odhcp6c.git] / src / odhcp6c.c
1 /**
2 * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
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 v2 as published by
6 * the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 */
14
15 #include <time.h>
16 #include <errno.h>
17 #include <fcntl.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <stddef.h>
21 #include <unistd.h>
22 #include <syslog.h>
23 #include <signal.h>
24 #include <string.h>
25 #include <stdbool.h>
26
27 #include <net/if.h>
28 #include <sys/wait.h>
29 #include <sys/syscall.h>
30 #include <arpa/inet.h>
31
32 #include "odhcp6c.h"
33 #include "ra.h"
34
35 #ifdef EXT_BFD_PING
36 #include "bfd.h"
37 #endif
38
39
40 static void sighandler(int signal);
41 static int usage(void);
42
43 static uint8_t *state_data[_STATE_MAX] = {NULL};
44 static size_t state_len[_STATE_MAX] = {0};
45
46 static volatile bool signal_io = false;
47 static volatile bool signal_usr1 = false;
48 static volatile bool signal_usr2 = false;
49 static volatile bool signal_term = false;
50
51 static int urandom_fd = -1, allow_slaac_only = 0;
52 static bool bound = false, release = true;
53 static time_t last_update = 0;
54
55 static unsigned int min_update_interval = DEFAULT_MIN_UPDATE_INTERVAL;
56
57 int main(_unused int argc, char* const argv[])
58 {
59 // Allocate ressources
60 const char *pidfile = NULL;
61 const char *script = "/usr/sbin/odhcp6c-update";
62 ssize_t l;
63 uint8_t buf[134];
64 char *optpos;
65 uint16_t opttype;
66 uint16_t optlen;
67 enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
68 enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_NONE;
69 int ia_pd_iaid_index = 0;
70 static struct in6_addr ifid = IN6ADDR_ANY_INIT;
71 int sol_timeout = DHCPV6_SOL_MAX_RT;
72
73 #ifdef EXT_BFD_PING
74 int bfd_interval = 0, bfd_loss = 3;
75 #endif
76
77 bool help = false, daemonize = false;
78 int logopt = LOG_PID;
79 int c;
80 unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
81
82 while ((c = getopt(argc, argv, "S::N:V:P:FB:c:i:r:Ru:s:kt:m:hedp:fa")) != -1) {
83 switch (c) {
84 case 'S':
85 allow_slaac_only = (optarg) ? atoi(optarg) : -1;
86 break;
87
88 case 'N':
89 if (!strcmp(optarg, "force")) {
90 ia_na_mode = IA_MODE_FORCE;
91 allow_slaac_only = -1;
92 } else if (!strcmp(optarg, "none")) {
93 ia_na_mode = IA_MODE_NONE;
94 } else if (!strcmp(optarg, "try")) {
95 ia_na_mode = IA_MODE_TRY;
96 } else{
97 help = true;
98 }
99 break;
100
101 case 'V':
102 l = script_unhexlify(buf, sizeof(buf), optarg);
103 if (!l)
104 help=true;
105
106 odhcp6c_add_state(STATE_VENDORCLASS, buf, l);
107
108 break;
109 case 'P':
110 if (ia_pd_mode == IA_MODE_NONE)
111 ia_pd_mode = IA_MODE_TRY;
112
113 if (allow_slaac_only >= 0 && allow_slaac_only < 10)
114 allow_slaac_only = 10;
115
116 char *iaid_begin;
117 int iaid_len = 0;
118
119 int prefix_length = strtoul(optarg, &iaid_begin, 10);
120
121 if (*iaid_begin != '\0' && *iaid_begin != ',' && *iaid_begin != ':') {
122 syslog(LOG_ERR, "invalid argument: '%s'", optarg);
123 return 1;
124 }
125
126 struct odhcp6c_request_prefix prefix = { 0, prefix_length };
127
128 if (*iaid_begin == ',' && (iaid_len = strlen(iaid_begin)) > 1)
129 memcpy(&prefix.iaid, iaid_begin + 1, iaid_len > 4 ? 4 : iaid_len);
130 else if (*iaid_begin == ':')
131 prefix.iaid = htonl((uint32_t)strtoul(&iaid_begin[1], NULL, 16));
132 else
133 prefix.iaid = htonl(++ia_pd_iaid_index);
134
135 odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix));
136
137 break;
138
139 case 'F':
140 allow_slaac_only = -1;
141 ia_pd_mode = IA_MODE_FORCE;
142 break;
143
144 #ifdef EXT_BFD_PING
145 case 'B':
146 bfd_interval = atoi(optarg);
147 break;
148 #endif
149
150 case 'c':
151 l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
152 if (l > 0) {
153 buf[0] = 0;
154 buf[1] = DHCPV6_OPT_CLIENTID;
155 buf[2] = 0;
156 buf[3] = l;
157 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
158 } else {
159 help = true;
160 }
161 break;
162
163 case 'i':
164 if (inet_pton(AF_INET6, optarg, &ifid) != 1)
165 help = true;
166 break;
167
168 case 'r':
169 optpos = optarg;
170 while (optpos[0]) {
171 opttype = htons(strtoul(optarg, &optpos, 10));
172 if (optpos == optarg)
173 break;
174 else if (optpos[0])
175 optarg = &optpos[1];
176 odhcp6c_add_state(STATE_ORO, &opttype, 2);
177 }
178 break;
179
180 case 'R':
181 client_options |= DHCPV6_STRICT_OPTIONS;
182 break;
183
184 case 'u':
185 optlen = htons(strlen(optarg));
186 odhcp6c_add_state(STATE_USERCLASS, &optlen, 2);
187 odhcp6c_add_state(STATE_USERCLASS, optarg, strlen(optarg));
188 break;
189
190 case 's':
191 script = optarg;
192 break;
193
194 case 'k':
195 release = false;
196 break;
197
198 case 't':
199 sol_timeout = atoi(optarg);
200 break;
201
202 case 'm':
203 min_update_interval = atoi(optarg);
204 break;
205
206 case 'e':
207 logopt |= LOG_PERROR;
208 break;
209
210 case 'd':
211 daemonize = true;
212 break;
213
214 case 'p':
215 pidfile = optarg;
216 break;
217
218 case 'f':
219 client_options &= ~DHCPV6_CLIENT_FQDN;
220 break;
221
222 case 'a':
223 client_options &= ~DHCPV6_ACCEPT_RECONFIGURE;
224 break;
225
226 default:
227 help = true;
228 break;
229 }
230 }
231
232 openlog("odhcp6c", logopt, LOG_DAEMON);
233 const char *ifname = argv[optind];
234
235 if (help || !ifname)
236 return usage();
237
238 signal(SIGIO, sighandler);
239 signal(SIGHUP, sighandler);
240 signal(SIGINT, sighandler);
241 signal(SIGCHLD, sighandler);
242 signal(SIGTERM, sighandler);
243 signal(SIGUSR1, sighandler);
244 signal(SIGUSR2, sighandler);
245
246 if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
247 init_dhcpv6(ifname, client_options, sol_timeout) ||
248 ra_init(ifname, &ifid) || script_init(script, ifname)) {
249 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
250 return 3;
251 }
252
253 if (daemonize) {
254 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
255 if (daemon(0, 0)) {
256 syslog(LOG_ERR, "Failed to daemonize: %s",
257 strerror(errno));
258 return 4;
259 }
260
261 char pidbuf[128];
262 if (!pidfile) {
263 snprintf(pidbuf, sizeof(pidbuf),
264 "/var/run/odhcp6c.%s.pid", ifname);
265 pidfile = pidbuf;
266 }
267
268 int fd = open(pidfile, O_WRONLY | O_CREAT, 0644);
269 if (fd >= 0) {
270 char buf[8];
271 int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
272 write(fd, buf, len);
273 close(fd);
274 }
275 }
276
277 script_call("started");
278
279 while (!signal_term) { // Main logic
280 odhcp6c_clear_state(STATE_SERVER_ID);
281 odhcp6c_clear_state(STATE_IA_NA);
282 odhcp6c_clear_state(STATE_IA_PD);
283 odhcp6c_clear_state(STATE_SNTP_IP);
284 odhcp6c_clear_state(STATE_NTP_IP);
285 odhcp6c_clear_state(STATE_NTP_FQDN);
286 odhcp6c_clear_state(STATE_SIP_IP);
287 odhcp6c_clear_state(STATE_SIP_FQDN);
288 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
289 bound = false;
290
291 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
292
293 signal_usr1 = signal_usr2 = false;
294 int mode = dhcpv6_request(DHCPV6_MSG_SOLICIT);
295 odhcp6c_signal_process();
296
297 if (mode < 0)
298 continue;
299
300 do {
301 int res = dhcpv6_request(mode == DHCPV6_STATELESS ?
302 DHCPV6_MSG_INFO_REQ : DHCPV6_MSG_REQUEST);
303 bool signalled = odhcp6c_signal_process();
304
305 if (res > 0)
306 break;
307 else if (signalled) {
308 mode = -1;
309 break;
310 }
311
312 mode = dhcpv6_promote_server_cand();
313 } while (mode > DHCPV6_UNKNOWN);
314
315 if (mode < 0)
316 continue;
317
318 switch (mode) {
319 case DHCPV6_STATELESS:
320 bound = true;
321 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
322
323 while (!signal_usr2 && !signal_term) {
324 signal_usr1 = false;
325 script_call("informed");
326
327 int res = dhcpv6_poll_reconfigure();
328 odhcp6c_signal_process();
329
330 if (res > 0)
331 continue;
332
333 if (signal_usr1) {
334 signal_usr1 = false; // Acknowledged
335 continue;
336 }
337 if (signal_usr2 || signal_term)
338 break;
339
340 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
341 odhcp6c_signal_process();
342 if (signal_usr1)
343 continue;
344 else if (res < 0)
345 break;
346 }
347 break;
348
349 case DHCPV6_STATEFUL:
350 script_call("bound");
351 bound = true;
352 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
353 #ifdef EXT_BFD_PING
354 if (bfd_interval > 0)
355 bfd_start(ifname, bfd_loss, bfd_interval);
356 #endif
357
358 while (!signal_usr2 && !signal_term) {
359 // Renew Cycle
360 // Wait for T1 to expire or until we get a reconfigure
361 int res = dhcpv6_poll_reconfigure();
362 odhcp6c_signal_process();
363 if (res > 0) {
364 script_call("updated");
365 continue;
366 }
367
368 // Handle signal, if necessary
369 if (signal_usr1)
370 signal_usr1 = false; // Acknowledged
371 if (signal_usr2 || signal_term)
372 break; // Other signal type
373
374 // Send renew as T1 expired
375 size_t ia_pd_len, ia_na_len;
376 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
377 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
378
379 // If we have any IAs, send renew, otherwise request
380 if (ia_pd_len == 0 && ia_na_len == 0)
381 res = dhcpv6_request(DHCPV6_MSG_REQUEST);
382 else
383 res = dhcpv6_request(DHCPV6_MSG_RENEW);
384
385 odhcp6c_signal_process();
386 if (res > 0) { // Renew was succesfull
387 // Publish updates
388 script_call("updated");
389 continue; // Renew was successful
390 }
391
392 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
393
394 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
395 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
396
397 if (ia_pd_len == 0 && ia_na_len == 0)
398 break;
399
400 // If we have IAs, try rebind otherwise restart
401 res = dhcpv6_request(DHCPV6_MSG_REBIND);
402 odhcp6c_signal_process();
403
404 if (res > 0)
405 script_call("rebound");
406 else {
407 #ifdef EXT_BFD_PING
408 bfd_stop();
409 #endif
410 break;
411 }
412 }
413 break;
414
415 default:
416 break;
417 }
418
419 size_t ia_pd_len, ia_na_len, server_id_len;
420 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
421 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
422 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
423
424 // Add all prefixes to lost prefixes
425 bound = false;
426 script_call("unbound");
427
428 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
429 dhcpv6_request(DHCPV6_MSG_RELEASE);
430
431 odhcp6c_clear_state(STATE_IA_NA);
432 odhcp6c_clear_state(STATE_IA_PD);
433 }
434
435 script_call("stopped");
436 return 0;
437 }
438
439
440 static int usage(void)
441 {
442 const char buf[] =
443 "Usage: odhcp6c [options] <interface>\n"
444 "\nFeature options:\n"
445 " -S <time> Wait at least <time> sec for a DHCP-server (0)\n"
446 " -N <mode> Mode for requesting addresses [try|force|none]\n"
447 " -P <length> Request IPv6-Prefix (0 = auto)\n"
448 " -F Force IPv6-Prefix\n"
449 " -V <class> Set vendor-class option (base-16 encoded)\n"
450 #ifdef EXT_BFD_PING
451 " -B <interval> Enable BFD ping check\n"
452 #endif
453 " -c <clientid> Override client-ID (base-16 encoded)\n"
454 " -i <iface-id> Use a custom interface identifier for RA handling\n"
455 " -r <options> Options to be requested (comma-separated)\n"
456 " -R Do not request any options except those specified with -r\n"
457 " -s <script> Status update script (/usr/sbin/odhcp6c-update)\n"
458 " -a Don't send Accept Reconfigure option\n"
459 " -f Don't send Client FQDN option\n"
460 " -k Don't send a RELEASE when stopping\n"
461 " -t <seconds> Maximum timeout for DHCPv6-SOLICIT (3600)\n"
462 " -m <seconds> Minimum time between accepting updates (30)\n"
463 "\nInvocation options:\n"
464 " -p <pidfile> Set pidfile (/var/run/odhcp6c.pid)\n"
465 " -d Daemonize\n"
466 " -e Write logmessages to stderr\n"
467 //" -v Increase logging verbosity\n"
468 " -h Show this help\n\n";
469 write(STDERR_FILENO, buf, sizeof(buf));
470 return 1;
471 }
472
473
474 // Don't want to pull-in librt and libpthread just for a monotonic clock...
475 uint64_t odhcp6c_get_milli_time(void)
476 {
477 struct timespec t = {0, 0};
478 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
479 return ((uint64_t)t.tv_sec) * 1000 + ((uint64_t)t.tv_nsec) / 1000000;
480 }
481
482
483 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
484 {
485 if (len == 0)
486 return state_data[state] + state_len[state];
487 else if (state_len[state] + len > 1024)
488 return NULL;
489
490 uint8_t *n = realloc(state_data[state], state_len[state] + len);
491 if (n || state_len[state] + len == 0) {
492 state_data[state] = n;
493 n += state_len[state];
494 state_len[state] += len;
495 }
496 return n;
497 }
498
499
500 bool odhcp6c_signal_process(void)
501 {
502 while (signal_io) {
503 signal_io = false;
504
505 bool ra_updated = ra_process();
506
507 if (ra_link_up())
508 signal_usr2 = true;
509
510 if (ra_updated && (bound || allow_slaac_only == 0))
511 script_call("ra-updated"); // Immediate process urgent events
512 else if (ra_updated && !bound && allow_slaac_only > 0)
513 script_delay_call("ra-updated", allow_slaac_only);
514
515 #ifdef EXT_BFD_PING
516 bfd_receive();
517 #endif
518 }
519
520 return signal_usr1 || signal_usr2 || signal_term;
521 }
522
523
524 void odhcp6c_clear_state(enum odhcp6c_state state)
525 {
526 state_len[state] = 0;
527 }
528
529
530 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
531 {
532 uint8_t *n = odhcp6c_resize_state(state, len);
533 if (n)
534 memcpy(n, data, len);
535 }
536
537 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
538 {
539 ssize_t len_after = state_len[state] - offset;
540 if (len_after < 0)
541 return;
542
543 uint8_t *n = odhcp6c_resize_state(state, len);
544 if (n) {
545 uint8_t *sdata = state_data[state];
546
547 memmove(sdata + offset + len, sdata + offset, len_after);
548 memcpy(sdata + offset, data, len);
549 }
550 }
551
552 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
553 {
554 uint8_t *data = state_data[state];
555 ssize_t len_after = state_len[state] - (offset + len);
556 if (len_after < 0)
557 return state_len[state];
558
559 memmove(data + offset, data + offset + len, len_after);
560 return state_len[state] -= len;
561 }
562
563
564 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
565 {
566 *len = state_len[state];
567 void *data = state_data[state];
568
569 state_len[state] = 0;
570 state_data[state] = NULL;
571
572 return data;
573 }
574
575
576 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
577 {
578 *len = state_len[state];
579 return state_data[state];
580 }
581
582
583 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
584 {
585 size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
586 struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
587 struct odhcp6c_entry *x = NULL;
588
589 for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
590 if (!memcmp(c, new, cmplen))
591 return c;
592
593 return NULL;
594 }
595
596
597 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
598 {
599 size_t len;
600 struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
601 struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
602
603 if (x && x->valid > new->valid && new->valid < safe)
604 new->valid = safe;
605
606 if (new->valid > 0) {
607 if (x) {
608 if (new->valid >= x->valid && new->valid != UINT32_MAX &&
609 new->valid - x->valid < min_update_interval &&
610 new->preferred >= x->preferred &&
611 new->preferred != UINT32_MAX &&
612 new->preferred - x->preferred < min_update_interval &&
613 x->class == new->class)
614 return false;
615 x->valid = new->valid;
616 x->preferred = new->preferred;
617 x->t1 = new->t1;
618 x->t2 = new->t2;
619 x->class = new->class;
620 x->iaid = new->iaid;
621 } else {
622 odhcp6c_add_state(state, new, sizeof(*new));
623 }
624 } else if (x) {
625 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
626 }
627 return true;
628 }
629
630
631 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
632 {
633 return odhcp6c_update_entry_safe(state, new, 0);
634 }
635
636
637 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
638 {
639 size_t len;
640 struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
641 for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
642 if (c->t1 < elapsed)
643 c->t1 = 0;
644 else if (c->t1 != UINT32_MAX)
645 c->t1 -= elapsed;
646
647 if (c->t2 < elapsed)
648 c->t2 = 0;
649 else if (c->t2 != UINT32_MAX)
650 c->t2 -= elapsed;
651
652 if (c->preferred < elapsed)
653 c->preferred = 0;
654 else if (c->preferred != UINT32_MAX)
655 c->preferred -= elapsed;
656
657 if (c->valid < elapsed)
658 c->valid = 0;
659 else if (c->valid != UINT32_MAX)
660 c->valid -= elapsed;
661
662 if (!c->valid)
663 odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
664 }
665 }
666
667
668 void odhcp6c_expire(void)
669 {
670 time_t now = odhcp6c_get_milli_time() / 1000;
671 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
672 last_update = now;
673
674 odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
675 odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
676 odhcp6c_expire_list(STATE_RA_DNS, elapsed);
677 odhcp6c_expire_list(STATE_IA_NA, elapsed);
678 odhcp6c_expire_list(STATE_IA_PD, elapsed);
679 }
680
681
682 uint32_t odhcp6c_elapsed(void)
683 {
684 return odhcp6c_get_milli_time() / 1000 - last_update;
685 }
686
687
688 void odhcp6c_random(void *buf, size_t len)
689 {
690 read(urandom_fd, buf, len);
691 }
692
693 bool odhcp6c_is_bound(void)
694 {
695 return bound;
696 }
697
698 static void sighandler(int signal)
699 {
700 if (signal == SIGCHLD)
701 while (waitpid(-1, NULL, WNOHANG) > 0);
702 else if (signal == SIGUSR1)
703 signal_usr1 = true;
704 else if (signal == SIGUSR2)
705 signal_usr2 = true;
706 else if (signal == SIGIO)
707 signal_io = true;
708 else
709 signal_term = true;
710 }
Openwrt DHCPv6 Client