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