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