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allow disabling "client fqdn" and "accept reconfiguration" options
[project/odhcp6c.git] / src / odhcp6c.c
1 /**
2 * Copyright (C) 2012-2013 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 int main(_unused int argc, char* const argv[])
56 {
57 // Allocate ressources
58 const char *pidfile = NULL;
59 const char *script = "/usr/sbin/odhcp6c-update";
60 ssize_t l;
61 uint8_t buf[134];
62 char *optpos;
63 uint16_t opttype;
64 enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
65 enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_TRY;
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 #ifdef EXT_BFD_PING
71 int bfd_interval = 0, bfd_loss = 3;
72 #endif
73
74 bool help = false, daemonize = false;
75 int logopt = LOG_PID;
76 int c;
77 unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
78
79 while ((c = getopt(argc, argv, "S::N:P:FB:c:i:r:Rs:kt:hedp:fa")) != -1) {
80 switch (c) {
81 case 'S':
82 allow_slaac_only = (optarg) ? atoi(optarg) : -1;
83 break;
84
85 case 'N':
86 if (!strcmp(optarg, "force")) {
87 ia_na_mode = IA_MODE_FORCE;
88 allow_slaac_only = -1;
89 } else if (!strcmp(optarg, "none")) {
90 ia_na_mode = IA_MODE_NONE;
91 } else if (!strcmp(optarg, "try")) {
92 ia_na_mode = IA_MODE_TRY;
93 } else{
94 help = true;
95 }
96 break;
97
98 case 'P':
99 if (allow_slaac_only >= 0 && allow_slaac_only < 10)
100 allow_slaac_only = 10;
101
102 char *iaid_begin;
103 int iaid_len = 0;
104
105 int prefix_length = strtoul(optarg, &iaid_begin, 10);
106
107 if (*iaid_begin != '\0' && *iaid_begin != ',') {
108 syslog(LOG_ERR, "invalid argument: '%s'", optarg);
109 return 1;
110 }
111
112 struct odhcp6c_request_prefix prefix = { 0, prefix_length };
113
114 if (*iaid_begin == ',' && (iaid_len = strlen(iaid_begin)) > 1)
115 memcpy(&prefix.iaid, iaid_begin + 1, iaid_len > 4 ? 4 : iaid_len);
116 else
117 prefix.iaid = ++ia_pd_iaid_index;
118
119 odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix));
120
121 break;
122
123 case 'F':
124 allow_slaac_only = -1;
125 ia_pd_mode = IA_MODE_FORCE;
126 break;
127
128 #ifdef EXT_BFD_PING
129 case 'B':
130 bfd_interval = atoi(optarg);
131 break;
132 #endif
133
134 case 'c':
135 l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
136 if (l > 0) {
137 buf[0] = 0;
138 buf[1] = DHCPV6_OPT_CLIENTID;
139 buf[2] = 0;
140 buf[3] = l;
141 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
142 } else {
143 help = true;
144 }
145 break;
146
147 case 'i':
148 if (inet_pton(AF_INET6, optarg, &ifid) != 1)
149 help = true;
150 break;
151
152 case 'r':
153 optpos = optarg;
154 while (optpos[0]) {
155 opttype = htons(strtoul(optarg, &optpos, 10));
156 if (optpos == optarg)
157 break;
158 else if (optpos[0])
159 optarg = &optpos[1];
160 odhcp6c_add_state(STATE_ORO, &opttype, 2);
161 }
162 break;
163
164 case 'R':
165 client_options |= DHCPV6_STRICT_OPTIONS;
166 break;
167
168 case 's':
169 script = optarg;
170 break;
171
172 case 'k':
173 release = false;
174 break;
175
176 case 't':
177 sol_timeout = atoi(optarg);
178 break;
179
180 case 'e':
181 logopt |= LOG_PERROR;
182 break;
183
184 case 'd':
185 daemonize = true;
186 break;
187
188 case 'p':
189 pidfile = optarg;
190 break;
191
192 case 'f':
193 client_options &= ~DHCPV6_CLIENT_FQDN;
194 break;
195
196 case 'a':
197 client_options &= ~DHCPV6_ACCEPT_RECONFIGURE;
198 break;
199
200 default:
201 help = true;
202 break;
203 }
204 }
205
206 openlog("odhcp6c", logopt, LOG_DAEMON);
207 const char *ifname = argv[optind];
208
209 if (help || !ifname)
210 return usage();
211
212 signal(SIGIO, sighandler);
213 signal(SIGHUP, sighandler);
214 signal(SIGINT, sighandler);
215 signal(SIGCHLD, sighandler);
216 signal(SIGTERM, sighandler);
217 signal(SIGUSR1, sighandler);
218 signal(SIGUSR2, sighandler);
219
220 if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
221 init_dhcpv6(ifname, client_options, sol_timeout) ||
222 ra_init(ifname, &ifid) || script_init(script, ifname)) {
223 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
224 return 3;
225 }
226
227 if (daemonize) {
228 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
229 if (daemon(0, 0)) {
230 syslog(LOG_ERR, "Failed to daemonize: %s",
231 strerror(errno));
232 return 4;
233 }
234
235 char pidbuf[128];
236 if (!pidfile) {
237 snprintf(pidbuf, sizeof(pidbuf),
238 "/var/run/odhcp6c.%s.pid", ifname);
239 pidfile = pidbuf;
240 }
241
242 int fd = open(pidfile, O_WRONLY | O_CREAT);
243 if (fd >= 0) {
244 char buf[8];
245 int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
246 write(fd, buf, len);
247 close(fd);
248 }
249 }
250
251 script_call("started");
252
253 while (!signal_term) { // Main logic
254 odhcp6c_clear_state(STATE_SERVER_ID);
255 odhcp6c_clear_state(STATE_IA_NA);
256 odhcp6c_clear_state(STATE_IA_PD);
257 odhcp6c_clear_state(STATE_SNTP_IP);
258 odhcp6c_clear_state(STATE_NTP_IP);
259 odhcp6c_clear_state(STATE_NTP_FQDN);
260 odhcp6c_clear_state(STATE_SIP_IP);
261 odhcp6c_clear_state(STATE_SIP_FQDN);
262 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
263 bound = false;
264
265 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
266
267 signal_usr1 = signal_usr2 = false;
268 int mode = dhcpv6_request(DHCPV6_MSG_SOLICIT);
269 odhcp6c_signal_process();
270
271 if (mode < 0)
272 continue;
273
274 do {
275 int res = dhcpv6_request(mode == DHCPV6_STATELESS ?
276 DHCPV6_MSG_INFO_REQ : DHCPV6_MSG_REQUEST);
277 bool signalled = odhcp6c_signal_process();
278
279 if (res > 0)
280 break;
281 else if (signalled) {
282 mode = -1;
283 break;
284 }
285
286 mode = dhcpv6_promote_server_cand();
287 } while (mode > DHCPV6_UNKNOWN);
288
289 if (mode < 0)
290 continue;
291
292 switch (mode) {
293 case DHCPV6_STATELESS:
294 bound = true;
295 syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
296
297 while (!signal_usr2 && !signal_term) {
298 signal_usr1 = false;
299 script_call("informed");
300
301 int res = dhcpv6_poll_reconfigure();
302 odhcp6c_signal_process();
303
304 if (res > 0)
305 continue;
306
307 if (signal_usr1) {
308 signal_usr1 = false; // Acknowledged
309 continue;
310 }
311 if (signal_usr2 || signal_term)
312 break;
313
314 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
315 odhcp6c_signal_process();
316 if (signal_usr1)
317 continue;
318 else if (res < 0)
319 break;
320 }
321 break;
322
323 case DHCPV6_STATEFUL:
324 script_call("bound");
325 bound = true;
326 syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
327 #ifdef EXT_BFD_PING
328 if (bfd_interval > 0)
329 bfd_start(ifname, bfd_loss, bfd_interval);
330 #endif
331
332 while (!signal_usr2 && !signal_term) {
333 // Renew Cycle
334 // Wait for T1 to expire or until we get a reconfigure
335 int res = dhcpv6_poll_reconfigure();
336 odhcp6c_signal_process();
337 if (res > 0) {
338 script_call("updated");
339 continue;
340 }
341
342 // Handle signal, if necessary
343 if (signal_usr1)
344 signal_usr1 = false; // Acknowledged
345 if (signal_usr2 || signal_term)
346 break; // Other signal type
347
348 // Send renew as T1 expired
349 size_t ia_pd_len, ia_na_len;
350 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
351 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
352
353 // If we have any IAs, send renew, otherwise request
354 if (ia_pd_len == 0 && ia_na_len == 0)
355 res = dhcpv6_request(DHCPV6_MSG_REQUEST);
356 else
357 res = dhcpv6_request(DHCPV6_MSG_RENEW);
358
359 odhcp6c_signal_process();
360 if (res > 0) { // Renew was succesfull
361 // Publish updates
362 script_call("updated");
363 continue; // Renew was successful
364 }
365
366 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
367
368 // If we have IAs, try rebind otherwise restart
369 res = dhcpv6_request(DHCPV6_MSG_REBIND);
370 odhcp6c_signal_process();
371
372 if (res > 0)
373 script_call("rebound");
374 else {
375 #ifdef EXT_BFD_PING
376 bfd_stop();
377 #endif
378 break;
379 }
380 }
381 break;
382
383 default:
384 break;
385 }
386
387 size_t ia_pd_len, ia_na_len, server_id_len;
388 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
389 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
390 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
391
392 // Add all prefixes to lost prefixes
393 bound = false;
394 script_call("unbound");
395
396 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
397 dhcpv6_request(DHCPV6_MSG_RELEASE);
398
399 odhcp6c_clear_state(STATE_IA_NA);
400 odhcp6c_clear_state(STATE_IA_PD);
401 }
402
403 script_call("stopped");
404 return 0;
405 }
406
407
408 static int usage(void)
409 {
410 const char buf[] =
411 "Usage: odhcp6c [options] <interface>\n"
412 "\nFeature options:\n"
413 " -S <time> Wait at least <time> sec for a DHCP-server (0)\n"
414 " -N <mode> Mode for requesting addresses [try|force|none]\n"
415 " -P <length> Request IPv6-Prefix (0 = auto)\n"
416 " -F Force IPv6-Prefix\n"
417 #ifdef EXT_BFD_PING
418 " -B <interval> Enable BFD ping check\n"
419 #endif
420 " -c <clientid> Override client-ID (base-16 encoded)\n"
421 " -i <iface-id> Use a custom interface identifier for RA handling\n"
422 " -r <options> Options to be requested (comma-separated)\n"
423 " -R Do not request any options except those specified with -r\n"
424 " -s <script> Status update script (/usr/sbin/odhcp6c-update)\n"
425 " -a Don't send Accept Reconfigure option\n"
426 " -f Don't send Client FQDN option\n"
427 " -k Don't send a RELEASE when stopping\n"
428 " -t <seconds> Maximum timeout for DHCPv6-SOLICIT (120)\n"
429 "\nInvocation options:\n"
430 " -p <pidfile> Set pidfile (/var/run/6relayd.pid)\n"
431 " -d Daemonize\n"
432 " -e Write logmessages to stderr\n"
433 //" -v Increase logging verbosity\n"
434 " -h Show this help\n\n";
435 write(STDERR_FILENO, buf, sizeof(buf));
436 return 1;
437 }
438
439
440 // Don't want to pull-in librt and libpthread just for a monotonic clock...
441 uint64_t odhcp6c_get_milli_time(void)
442 {
443 struct timespec t = {0, 0};
444 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
445 return t.tv_sec * 1000 + t.tv_nsec / 1000000;
446 }
447
448
449 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
450 {
451 if (len == 0)
452 return state_data[state] + state_len[state];
453 else if (state_len[state] + len > 1024)
454 return NULL;
455
456 uint8_t *n = realloc(state_data[state], state_len[state] + len);
457 if (n || state_len[state] + len == 0) {
458 state_data[state] = n;
459 n += state_len[state];
460 state_len[state] += len;
461 }
462 return n;
463 }
464
465
466 bool odhcp6c_signal_process(void)
467 {
468 while (signal_io) {
469 signal_io = false;
470
471 bool ra_updated = ra_process();
472
473 if (ra_link_up())
474 signal_usr2 = true;
475
476 if (ra_updated && (bound || allow_slaac_only == 0))
477 script_call("ra-updated"); // Immediate process urgent events
478 else if (ra_updated && !bound && allow_slaac_only > 0)
479 script_delay_call("ra-updated", allow_slaac_only);
480
481 #ifdef EXT_BFD_PING
482 bfd_receive();
483 #endif
484 }
485
486 return signal_usr1 || signal_usr2 || signal_term;
487 }
488
489
490 void odhcp6c_clear_state(enum odhcp6c_state state)
491 {
492 state_len[state] = 0;
493 }
494
495
496 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
497 {
498 uint8_t *n = odhcp6c_resize_state(state, len);
499 if (n)
500 memcpy(n, data, len);
501 }
502
503 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
504 {
505 ssize_t len_after = state_len[state] - offset;
506 if (len_after < 0)
507 return;
508
509 uint8_t *n = odhcp6c_resize_state(state, len);
510 if (n) {
511 uint8_t *sdata = state_data[state];
512
513 memmove(sdata + offset + len, sdata + offset, len_after);
514 memcpy(sdata + offset, data, len);
515 }
516 }
517
518 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
519 {
520 uint8_t *data = state_data[state];
521 ssize_t len_after = state_len[state] - (offset + len);
522 if (len_after < 0)
523 return state_len[state];
524
525 memmove(data + offset, data + offset + len, len_after);
526 return state_len[state] -= len;
527 }
528
529
530 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
531 {
532 *len = state_len[state];
533 void *data = state_data[state];
534
535 state_len[state] = 0;
536 state_data[state] = NULL;
537
538 return data;
539 }
540
541
542 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
543 {
544 *len = state_len[state];
545 return state_data[state];
546 }
547
548
549 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
550 {
551 size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
552 struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
553 struct odhcp6c_entry *x = NULL;
554
555 for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
556 if (!memcmp(c, new, cmplen))
557 return c;
558
559 return NULL;
560 }
561
562
563 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
564 {
565 size_t len;
566 struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
567 struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
568
569 if (x && x->valid > new->valid && new->valid < safe)
570 new->valid = safe;
571
572 if (new->valid > 0) {
573 if (x) {
574 if (new->valid >= x->valid && new->valid - x->valid < 60 &&
575 new->preferred >= x->preferred &&
576 new->preferred - x->preferred < 60 &&
577 x->class == new->class)
578 return false;
579 x->valid = new->valid;
580 x->preferred = new->preferred;
581 x->t1 = new->t1;
582 x->t2 = new->t2;
583 x->class = new->class;
584 x->iaid = new->iaid;
585 } else {
586 odhcp6c_add_state(state, new, sizeof(*new));
587 }
588 } else if (x) {
589 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
590 }
591 return true;
592 }
593
594
595 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
596 {
597 return odhcp6c_update_entry_safe(state, new, 0);
598 }
599
600
601 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
602 {
603 size_t len;
604 struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
605 for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
606 if (c->t1 < elapsed)
607 c->t1 = 0;
608 else if (c->t1 != UINT32_MAX)
609 c->t1 -= elapsed;
610
611 if (c->t2 < elapsed)
612 c->t2 = 0;
613 else if (c->t2 != UINT32_MAX)
614 c->t2 -= elapsed;
615
616 if (c->preferred < elapsed)
617 c->preferred = 0;
618 else if (c->preferred != UINT32_MAX)
619 c->preferred -= elapsed;
620
621 if (c->valid < elapsed)
622 c->valid = 0;
623 else if (c->valid != UINT32_MAX)
624 c->valid -= elapsed;
625
626 if (!c->valid)
627 odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
628 }
629 }
630
631
632 void odhcp6c_expire(void)
633 {
634 time_t now = odhcp6c_get_milli_time() / 1000;
635 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
636 last_update = now;
637
638 odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
639 odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
640 odhcp6c_expire_list(STATE_RA_DNS, elapsed);
641 odhcp6c_expire_list(STATE_IA_NA, elapsed);
642 odhcp6c_expire_list(STATE_IA_PD, elapsed);
643 }
644
645
646 uint32_t odhcp6c_elapsed(void)
647 {
648 return odhcp6c_get_milli_time() / 1000 - last_update;
649 }
650
651
652 void odhcp6c_random(void *buf, size_t len)
653 {
654 read(urandom_fd, buf, len);
655 }
656
657 bool odhcp6c_is_bound(void)
658 {
659 return bound;
660 }
661
662 static void sighandler(int signal)
663 {
664 if (signal == SIGCHLD)
665 while (waitpid(-1, NULL, WNOHANG) > 0);
666 else if (signal == SIGUSR1)
667 signal_usr1 = true;
668 else if (signal == SIGUSR2)
669 signal_usr2 = true;
670 else if (signal == SIGIO)
671 signal_io = true;
672 else
673 signal_term = true;
674 }
Openwrt DHCPv6 Client