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ra/dhcpv6: unify address change handling
[project/odhcpd.git] / src / dhcpv6-ia.c
1 /**
2 * Copyright (C) 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 "odhcpd.h"
16 #include "dhcpv6.h"
17 #include "dhcpv4.h"
18 #include "libubox/md5.h"
19 #include "libubox/usock.h"
20
21 #include <time.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <stdio.h>
25 #include <poll.h>
26 #include <alloca.h>
27 #include <resolv.h>
28 #include <limits.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <stdbool.h>
33 #include <arpa/inet.h>
34 #include <sys/timerfd.h>
35
36
37 static void reconf_timer(struct uloop_timeout *event);
38 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
39 static uint32_t serial = 0;
40 static uint8_t statemd5[16];
41
42
43 int dhcpv6_ia_init(void)
44 {
45 uloop_timeout_set(&reconf_event, 2000);
46 return 0;
47 }
48
49
50 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
51 {
52 if (c->managed_sock.fd.registered) {
53 ustream_free(&c->managed_sock.stream);
54 close(c->managed_sock.fd.fd);
55 }
56
57 if (c->head.next)
58 list_del(&c->head);
59
60 free(c->managed);
61 free(c->hostname);
62 free(c);
63 }
64
65
66 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
67 {
68 if (!enable && iface->ia_assignments.next) {
69 struct dhcpv6_assignment *c;
70 while (!list_empty(&iface->ia_assignments)) {
71 c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
72 free_dhcpv6_assignment(c);
73 }
74 }
75
76 if (enable && iface->dhcpv6 == RELAYD_SERVER) {
77 if (!iface->ia_assignments.next)
78 INIT_LIST_HEAD(&iface->ia_assignments);
79
80 if (list_empty(&iface->ia_assignments)) {
81 struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
82 if (!border) {
83 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
84 return -1;
85 }
86
87 border->length = 64;
88 list_add(&border->head, &iface->ia_assignments);
89 }
90
91 // Parse static entries
92 struct lease *lease;
93 list_for_each_entry(lease, &leases, head) {
94 // Construct entry
95 struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
96 if (!a) {
97 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
98 iface->ifname);
99 return -1;
100 }
101
102 a->clid_len = lease->duid_len;
103 a->length = 128;
104 if (lease->hostid) {
105 a->assigned = lease->hostid;
106 } else {
107 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
108 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
109 }
110 odhcpd_urandom(a->key, sizeof(a->key));
111 memcpy(a->clid_data, lease->duid, a->clid_len);
112 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
113
114 // Assign to all interfaces
115 struct dhcpv6_assignment *c;
116 list_for_each_entry(c, &iface->ia_assignments, head) {
117 if (c->length != 128 || c->assigned > a->assigned) {
118 list_add_tail(&a->head, &c->head);
119 break;
120 } else if (c->assigned == a->assigned) {
121 // Already an assignment with that number
122 break;
123 }
124 }
125
126 if (a->head.next) {
127 if (lease->hostname[0]) {
128 free(a->hostname);
129 a->hostname = strdup(lease->hostname);
130 }
131 } else {
132 free(a->hostname);
133 free(a);
134 }
135 }
136 }
137 return 0;
138 }
139
140
141 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
142 {
143 struct {
144 struct dhcpv6_client_header hdr;
145 uint16_t srvid_type;
146 uint16_t srvid_len;
147 uint16_t duid_type;
148 uint16_t hardware_type;
149 uint8_t mac[6];
150 uint16_t msg_type;
151 uint16_t msg_len;
152 uint8_t msg_id;
153 struct dhcpv6_auth_reconfigure auth;
154 uint16_t clid_type;
155 uint16_t clid_len;
156 uint8_t clid_data[128];
157 } __attribute__((packed)) reconf_msg = {
158 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
159 .srvid_type = htons(DHCPV6_OPT_SERVERID),
160 .srvid_len = htons(10),
161 .duid_type = htons(3),
162 .hardware_type = htons(1),
163 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
164 .msg_len = htons(1),
165 .msg_id = DHCPV6_MSG_RENEW,
166 .auth = {htons(DHCPV6_OPT_AUTH),
167 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
168 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
169 .clid_type = htons(DHCPV6_OPT_CLIENTID),
170 .clid_len = htons(assign->clid_len),
171 .clid_data = {0},
172 };
173
174 odhcpd_get_mac(iface, reconf_msg.mac);
175 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
176 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
177
178 md5_ctx_t md5;
179 uint8_t secretbytes[64];
180 memset(secretbytes, 0, sizeof(secretbytes));
181 memcpy(secretbytes, assign->key, sizeof(assign->key));
182
183 for (size_t i = 0; i < sizeof(secretbytes); ++i)
184 secretbytes[i] ^= 0x36;
185
186 md5_begin(&md5);
187 md5_hash(secretbytes, sizeof(secretbytes), &md5);
188 md5_hash(iov.iov_base, iov.iov_len, &md5);
189 md5_end(reconf_msg.auth.key, &md5);
190
191 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
192 secretbytes[i] ^= 0x36;
193 secretbytes[i] ^= 0x5c;
194 }
195
196 md5_begin(&md5);
197 md5_hash(secretbytes, sizeof(secretbytes), &md5);
198 md5_hash(reconf_msg.auth.key, 16, &md5);
199 md5_end(reconf_msg.auth.key, &md5);
200
201 return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
202 }
203
204
205 void dhcpv6_write_statefile(void)
206 {
207 md5_ctx_t md5;
208 md5_begin(&md5);
209
210 if (config.dhcp_statefile) {
211 time_t now = odhcpd_time(), wall_time = time(NULL);
212 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
213 if (fd < 0)
214 return;
215
216 lockf(fd, F_LOCK, 0);
217 if (ftruncate(fd, 0) < 0) {}
218
219 FILE *fp = fdopen(fd, "w");
220 if (!fp) {
221 close(fd);
222 return;
223 }
224
225 struct interface *iface;
226 list_for_each_entry(iface, &interfaces, head) {
227 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
228 continue;
229
230 if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
231 struct dhcpv6_assignment *c;
232 list_for_each_entry(c, &iface->ia_assignments, head) {
233 if (c->clid_len == 0 || c->managed_size < 0)
234 continue;
235
236 char ipbuf[INET6_ADDRSTRLEN];
237 char leasebuf[512];
238 char duidbuf[264];
239 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
240
241 // iface DUID iaid hostname lifetime assigned length [addrs...]
242 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
243 iface->ifname, duidbuf, ntohl(c->iaid),
244 (c->hostname ? c->hostname : "-"),
245 (unsigned)(c->valid_until > now ?
246 (c->valid_until - now + wall_time) : 0),
247 c->assigned, (unsigned)c->length);
248
249 struct in6_addr addr;
250 struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
251 size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
252 size_t m = 0;
253
254 for (size_t i = 0; i < addrlen; ++i)
255 if (addrs[i].preferred > addrs[m].preferred ||
256 (addrs[i].preferred == addrs[m].preferred &&
257 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
258 m = i;
259
260 for (size_t i = 0; i < addrlen; ++i) {
261 if (addrs[i].prefix > 96 || c->valid_until <= now ||
262 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
263 addrs[i].prefix == 64))
264 continue;
265
266 addr = addrs[i].addr;
267 if (c->length == 128)
268 addr.s6_addr32[3] = htonl(c->assigned);
269 else
270 addr.s6_addr32[1] |= htonl(c->assigned);
271
272 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
273
274 if (c->length == 128 && c->hostname) {
275 fputs(ipbuf, fp);
276
277 char b[256];
278 if (dn_expand(iface->search, iface->search + iface->search_len,
279 iface->search, b, sizeof(b)) > 0)
280 fprintf(fp, "\t%s.%s", c->hostname, b);
281
282 fprintf(fp, "\t%s\n", c->hostname);
283 md5_hash(ipbuf, strlen(ipbuf), &md5);
284 md5_hash(c->hostname, strlen(c->hostname), &md5);
285 }
286
287 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
288 (c->managed_size) ? addrs[i].prefix : c->length);
289 }
290 leasebuf[l - 1] = '\n';
291 fwrite(leasebuf, 1, l, fp);
292 }
293 }
294
295 if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
296 struct dhcpv4_assignment *c;
297 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
298 char ipbuf[INET6_ADDRSTRLEN];
299 char leasebuf[512];
300 char duidbuf[16];
301 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
302
303 // iface DUID iaid hostname lifetime assigned length [addrs...]
304 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
305 iface->ifname, duidbuf,
306 (c->hostname ? c->hostname : "-"),
307 (unsigned)(c->valid_until > now ?
308 (c->valid_until - now + wall_time) : 0),
309 c->addr);
310
311 struct in_addr addr = {htonl(c->addr)};
312 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
313
314 if (c->hostname[0]) {
315 fputs(ipbuf, fp);
316
317 char b[256];
318 if (dn_expand(iface->search, iface->search + iface->search_len,
319 iface->search, b, sizeof(b)) > 0)
320 fprintf(fp, "\t%s.%s", c->hostname, b);
321
322 fprintf(fp, "\t%s\n", c->hostname);
323 md5_hash(ipbuf, strlen(ipbuf), &md5);
324 md5_hash(c->hostname, strlen(c->hostname), &md5);
325 }
326
327 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
328 leasebuf[l - 1] = '\n';
329 fwrite(leasebuf, 1, l, fp);
330 }
331 }
332 }
333
334 fclose(fp);
335 }
336
337 uint8_t newmd5[16];
338 md5_end(newmd5, &md5);
339
340 if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
341 memcpy(statemd5, newmd5, sizeof(statemd5));
342 char *argv[2] = {config.dhcp_cb, NULL};
343 if (!vfork()) {
344 execv(argv[0], argv);
345 _exit(128);
346 }
347 }
348 }
349
350
351 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
352 {
353 if (a->length > 64 || a->managed_size < 0)
354 return;
355
356 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
357 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
358
359 for (size_t i = 0; i < addrlen; ++i) {
360 struct in6_addr prefix = addrs[i].addr;
361 prefix.s6_addr32[1] |= htonl(a->assigned);
362 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
363 iface, &a->peer.sin6_addr, 1024, add);
364 }
365 }
366
367
368 // More data was received from TCP connection
369 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
370 {
371 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
372 time_t now = odhcpd_time();
373 bool first = c->managed_size < 0;
374
375 for (;;) {
376 int pending;
377 char *data = ustream_get_read_buf(s, &pending);
378 char *end = memmem(data, pending, "\n\n", 2);
379
380 if (!end)
381 break;
382
383 end += 2;
384 end[-1] = 0;
385
386 c->managed_size = 0;
387 if (c->accept_reconf)
388 c->reconf_cnt = 1;
389
390 char *saveptr;
391 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
392 c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
393 struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
394
395 char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
396 if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
397 continue;
398
399 x = strtok_r(NULL, ",", &saveptr2);
400 if (sscanf(x, "%hhu", &n->prefix) < 1)
401 continue;
402
403 x = strtok_r(NULL, ",", &saveptr2);
404 if (sscanf(x, "%u", &n->preferred) < 1)
405 continue;
406
407 x = strtok_r(NULL, ",", &saveptr2);
408 if (sscanf(x, "%u", &n->valid) < 1)
409 continue;
410
411 if (n->preferred > n->valid)
412 continue;
413
414 if (UINT32_MAX - now < n->preferred)
415 n->preferred = UINT32_MAX;
416 else
417 n->preferred += now;
418
419 if (UINT32_MAX - now < n->valid)
420 n->valid = UINT32_MAX;
421 else
422 n->valid += now;
423
424 n->dprefix = 0;
425
426 ++c->managed_size;
427 }
428
429 ustream_consume(s, end - data);
430 }
431
432 if (first && c->managed_size == 0)
433 free_dhcpv6_assignment(c);
434 else if (first)
435 c->valid_until = now + 150;
436 }
437
438
439 // TCP transmission has ended, either because of success or timeout or other error
440 static void managed_handle_pd_done(struct ustream *s)
441 {
442 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
443 c->valid_until = odhcpd_time() + 15;
444 c->managed_size = 0;
445 if (c->accept_reconf)
446 c->reconf_cnt = 1;
447 }
448
449
450
451 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
452 {
453 struct dhcpv6_assignment *c;
454
455 if (iface->dhcpv6_pd_manager[0]) {
456 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
457 if (fd >= 0) {
458 char iaidbuf[298];
459 odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
460
461 assign->managed_sock.stream.notify_read = managed_handle_pd_data;
462 assign->managed_sock.stream.notify_state = managed_handle_pd_done;
463 ustream_fd_init(&assign->managed_sock, fd);
464 ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
465 iaidbuf, assign->iaid, assign->length);
466 ustream_write_pending(&assign->managed_sock.stream);
467 assign->managed_size = -1;
468 assign->valid_until = odhcpd_time() + 15;
469 list_add(&assign->head, &iface->ia_assignments);
470
471 // Wait initial period of up to 250ms for immediate assignment
472 struct pollfd pfd = { .fd = fd, .events = POLLIN };
473 poll(&pfd, 1, 250);
474 managed_handle_pd_data(&assign->managed_sock.stream, 0);
475
476 if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
477 return true;
478 }
479
480 return false;
481 } else if (iface->ia_addr_len < 1) {
482 return false;
483 }
484
485 // Try honoring the hint first
486 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
487 if (assign->assigned) {
488 list_for_each_entry(c, &iface->ia_assignments, head) {
489 if (c->length == 128 || c->length == 0)
490 continue;
491
492 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
493 list_add_tail(&assign->head, &c->head);
494 apply_lease(iface, assign, true);
495 return true;
496 }
497
498 if (c->assigned != 0)
499 current = (c->assigned + (1 << (64 - c->length)));
500 }
501 }
502
503 // Fallback to a variable assignment
504 current = 1;
505 list_for_each_entry(c, &iface->ia_assignments, head) {
506 if (c->length == 128 || c->length == 0)
507 continue;
508
509 current = (current + asize) & (~asize);
510 if (current + asize < c->assigned) {
511 assign->assigned = current;
512 list_add_tail(&assign->head, &c->head);
513 apply_lease(iface, assign, true);
514 return true;
515 }
516
517 if (c->assigned != 0)
518 current = (c->assigned + (1 << (64 - c->length)));
519 }
520
521 return false;
522 }
523
524
525 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
526 {
527 // Seed RNG with checksum of DUID
528 uint32_t seed = 0;
529 for (size_t i = 0; i < assign->clid_len; ++i)
530 seed += assign->clid_data[i];
531 srand(seed);
532
533 // Try to assign up to 100x
534 for (size_t i = 0; i < 100; ++i) {
535 uint32_t try;
536 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
537
538 struct dhcpv6_assignment *c;
539 list_for_each_entry(c, &iface->ia_assignments, head) {
540 if (c->length == 0)
541 continue;
542
543 if (c->assigned > try || c->length != 128) {
544 assign->assigned = try;
545 list_add_tail(&assign->head, &c->head);
546 return true;
547 } else if (c->assigned == try) {
548 break;
549 }
550 }
551 }
552
553 return false;
554 }
555
556 void dhcpv6_ia_preupdate(struct interface *iface)
557 {
558 if (iface->dhcpv6 != RELAYD_SERVER)
559 return;
560
561 struct dhcpv6_assignment *c, *border = list_last_entry(
562 &iface->ia_assignments, struct dhcpv6_assignment, head);
563 list_for_each_entry(c, &iface->ia_assignments, head)
564 if (c != border && !iface->managed)
565 apply_lease(iface, c, false);
566 }
567
568 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
569 {
570 if (iface->dhcpv6 != RELAYD_SERVER)
571 return;
572
573 int minprefix = -1;
574 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
575 if (iface->ia_addr[i].preferred > now &&
576 iface->ia_addr[i].prefix < 64 &&
577 iface->ia_addr[i].prefix > minprefix)
578 minprefix = iface->ia_addr[i].prefix;
579 }
580
581 struct dhcpv6_assignment *border = list_last_entry(
582 &iface->ia_assignments, struct dhcpv6_assignment, head);
583 if (minprefix > 32 && minprefix <= 64)
584 border->assigned = 1U << (64 - minprefix);
585 else
586 border->assigned = 0;
587
588 struct list_head reassign = LIST_HEAD_INIT(reassign);
589 struct dhcpv6_assignment *c, *d;
590 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
591 if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
592 continue;
593
594 if (c->length < 128 && c->assigned >= border->assigned && c != border)
595 list_move(&c->head, &reassign);
596 else if (c != border)
597 apply_lease(iface, c, true);
598
599 if (c->accept_reconf && c->reconf_cnt == 0) {
600 c->reconf_cnt = 1;
601 c->reconf_sent = now;
602 send_reconf(iface, c);
603
604 // Leave all other assignments of that client alone
605 struct dhcpv6_assignment *a;
606 list_for_each_entry(a, &iface->ia_assignments, head)
607 if (a != c && a->clid_len == c->clid_len &&
608 !memcmp(a->clid_data, c->clid_data, a->clid_len))
609 c->reconf_cnt = INT_MAX;
610 }
611 }
612
613 while (!list_empty(&reassign)) {
614 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
615 list_del(&c->head);
616 if (!assign_pd(iface, c)) {
617 c->assigned = 0;
618 list_add(&c->head, &iface->ia_assignments);
619 }
620 }
621
622 dhcpv6_write_statefile();
623 }
624
625
626 static void reconf_timer(struct uloop_timeout *event)
627 {
628 time_t now = odhcpd_time();
629 struct interface *iface;
630 list_for_each_entry(iface, &interfaces, head) {
631 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
632 continue;
633
634 struct dhcpv6_assignment *a, *n;
635 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
636 if (a->valid_until < now) {
637 if ((a->length < 128 && a->clid_len > 0) ||
638 (a->length == 128 && a->clid_len == 0)) {
639 list_del(&a->head);
640 free_dhcpv6_assignment(a);
641 }
642 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
643 now > a->reconf_sent + (1 << a->reconf_cnt)) {
644 ++a->reconf_cnt;
645 a->reconf_sent = now;
646 send_reconf(iface, a);
647 }
648 }
649 }
650 uloop_timeout_set(event, 2000);
651 }
652
653
654 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
655 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
656 struct interface *iface, bool request)
657 {
658 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
659 return 0;
660
661 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
662 size_t datalen = sizeof(out);
663 time_t now = odhcpd_time();
664
665 if (status) {
666 struct __attribute__((packed)) {
667 uint16_t type;
668 uint16_t len;
669 uint16_t value;
670 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
671 htons(status)};
672
673 memcpy(buf + datalen, &stat, sizeof(stat));
674 datalen += sizeof(stat);
675 } else {
676 if (a) {
677 uint32_t leasetime = iface->dhcpv4_leasetime;
678 if (leasetime == 0)
679 leasetime = 3600;
680 else if (leasetime < 60)
681 leasetime = 60;
682
683 uint32_t pref = leasetime;
684 uint32_t valid = leasetime;
685
686 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
687 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
688 size_t m = 0;
689
690 for (size_t i = 0; i < addrlen; ++i)
691 if (addrs[i].preferred > addrs[m].preferred ||
692 (addrs[i].preferred == addrs[m].preferred &&
693 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
694 m = i;
695
696 for (size_t i = 0; i < addrlen; ++i) {
697 uint32_t prefix_pref = addrs[i].preferred;
698 uint32_t prefix_valid = addrs[i].valid;
699
700 if (addrs[i].prefix > 96 ||
701 addrs[i].preferred <= (uint32_t)now)
702 continue;
703
704 if (prefix_pref != UINT32_MAX)
705 prefix_pref -= now;
706
707 if (prefix_valid != UINT32_MAX)
708 prefix_valid -= now;
709
710 if (a->length < 128) {
711 struct dhcpv6_ia_prefix p = {
712 .type = htons(DHCPV6_OPT_IA_PREFIX),
713 .len = htons(sizeof(p) - 4),
714 .preferred = htonl(prefix_pref),
715 .valid = htonl(prefix_valid),
716 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
717 .addr = addrs[i].addr
718 };
719 p.addr.s6_addr32[1] |= htonl(a->assigned);
720
721 size_t entrlen = sizeof(p) - 4;
722
723 if (datalen + entrlen + 4 > buflen ||
724 (a->assigned == 0 && a->managed_size == 0) ||
725 (!a->managed_size && a->length <= addrs[i].prefix))
726 continue;
727
728 memcpy(buf + datalen, &p, sizeof(p));
729 datalen += entrlen + 4;
730 } else {
731 struct dhcpv6_ia_addr n = {
732 .type = htons(DHCPV6_OPT_IA_ADDR),
733 .len = htons(sizeof(n) - 4),
734 .addr = addrs[i].addr,
735 .preferred = htonl(prefix_pref),
736 .valid = htonl(prefix_valid)
737 };
738 n.addr.s6_addr32[3] = htonl(a->assigned);
739 size_t entrlen = sizeof(n) - 4;
740
741 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
742 addrs[i].prefix == 64)
743 continue;
744
745 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
746 continue;
747
748 memcpy(buf + datalen, &n, sizeof(n));
749 datalen += entrlen + 4;
750 }
751
752 // Calculate T1 / T2 based on non-deprecated addresses
753 if (prefix_pref > 0) {
754 if (prefix_pref < pref)
755 pref = prefix_pref;
756
757 if (prefix_valid < valid)
758 valid = prefix_valid;
759 }
760 }
761
762 a->valid_until = valid + now;
763 out.t1 = htonl(pref * 5 / 10);
764 out.t2 = htonl(pref * 8 / 10);
765
766 if (!out.t1)
767 out.t1 = htonl(1);
768
769 if (!out.t2)
770 out.t2 = htonl(1);
771 }
772
773 if (!request) {
774 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
775 uint16_t otype, olen;
776 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
777 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
778 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
779 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
780 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
781 continue;
782
783 bool found = false;
784 if (a) {
785 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
786 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
787
788 for (size_t i = 0; i < addrlen; ++i) {
789 if (addrs[i].prefix > 96 ||
790 addrs[i].preferred <= (uint32_t)now)
791 continue;
792
793 struct in6_addr addr = addrs[i].addr;
794 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
795 addr.s6_addr32[1] |= htonl(a->assigned);
796
797 if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
798 p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
799 found = true;
800 } else {
801 addr.s6_addr32[3] = htonl(a->assigned);
802
803 if (!memcmp(&n->addr, &addr, sizeof(addr)))
804 found = true;
805 }
806 }
807 }
808
809 if (!found) {
810 if (otype == DHCPV6_OPT_IA_PREFIX) {
811 struct dhcpv6_ia_prefix inv = {
812 .type = htons(DHCPV6_OPT_IA_PREFIX),
813 .len = htons(sizeof(inv) - 4),
814 .preferred = 0,
815 .valid = 0,
816 .prefix = p->prefix,
817 .addr = p->addr
818 };
819
820 if (datalen + sizeof(inv) > buflen)
821 continue;
822
823 memcpy(buf + datalen, &inv, sizeof(inv));
824 datalen += sizeof(inv);
825 } else {
826 struct dhcpv6_ia_addr inv = {
827 .type = htons(DHCPV6_OPT_IA_ADDR),
828 .len = htons(sizeof(inv) - 4),
829 .addr = n->addr,
830 .preferred = 0,
831 .valid = 0
832 };
833
834 if (datalen + sizeof(inv) > buflen)
835 continue;
836
837 memcpy(buf + datalen, &inv, sizeof(inv));
838 datalen += sizeof(inv);
839 }
840 }
841 }
842 }
843 }
844
845 out.len = htons(datalen - 4);
846 memcpy(buf, &out, sizeof(out));
847 return datalen;
848 }
849
850
851 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
852 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
853 {
854 const char *type = "UNKNOWN";
855 const char *status = "UNKNOWN";
856
857 if (msgtype == DHCPV6_MSG_RENEW)
858 return;
859
860 switch (msgtype) {
861 case DHCPV6_MSG_SOLICIT:
862 type = "SOLICIT";
863 break;
864 case DHCPV6_MSG_REQUEST:
865 type = "REQUEST";
866 break;
867 case DHCPV6_MSG_CONFIRM:
868 type = "CONFIRM";
869 break;
870 case DHCPV6_MSG_RENEW:
871 type = "RENEW";
872 break;
873 case DHCPV6_MSG_REBIND:
874 type = "REBIND";
875 break;
876 case DHCPV6_MSG_RELEASE:
877 type = "RELEASE";
878 break;
879 case DHCPV6_MSG_DECLINE:
880 type = "DECLINE";
881 break;
882 }
883
884 switch (code) {
885 case DHCPV6_STATUS_OK:
886 status = "ok";
887 break;
888 case DHCPV6_STATUS_NOADDRSAVAIL:
889 status = "no addresses available";
890 break;
891 case DHCPV6_STATUS_NOBINDING:
892 status = "no binding";
893 break;
894 case DHCPV6_STATUS_NOTONLINK:
895 status = "not on-link";
896 break;
897 case DHCPV6_STATUS_NOPREFIXAVAIL:
898 status = "no prefix available";
899 break;
900 }
901
902 char leasebuf[256] = "";
903
904 if (a) {
905 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
906 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
907 size_t lbsize = 0;
908 char addrbuf[INET6_ADDRSTRLEN];
909
910 for (size_t i = 0; i < addrlen; ++i) {
911 if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
912 continue;
913
914 struct in6_addr addr = addrs[i].addr;
915 int prefix = a->managed ? addrs[i].prefix : a->length;
916 if (prefix == 128)
917 addr.s6_addr32[3] = htonl(a->assigned);
918 else
919 addr.s6_addr32[1] |= htonl(a->assigned);
920
921 inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
922 lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
923 }
924 }
925
926 syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
927 duidbuf, iface->ifname, status, leasebuf);
928 }
929
930
931
932 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
933 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
934 {
935 time_t now = odhcpd_time();
936 size_t response_len = 0;
937 const struct dhcpv6_client_header *hdr = data;
938 uint8_t *start = (uint8_t*)&hdr[1], *odata;
939 uint16_t otype, olen;
940
941 // Find and parse client-id and hostname
942 bool accept_reconf = false;
943 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
944 char hostname[256];
945 size_t hostname_len = 0;
946 bool notonlink = false;
947 char duidbuf[261];
948
949 dhcpv6_for_each_option(start, end, otype, olen, odata) {
950 if (otype == DHCPV6_OPT_CLIENTID) {
951 clid_data = odata;
952 clid_len = olen;
953
954 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
955 memcpy(mac, &odata[8], sizeof(mac));
956 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
957 memcpy(mac, &odata[4], sizeof(mac));
958
959 if (olen <= 130)
960 odhcpd_hexlify(duidbuf, odata, olen);
961 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
962 uint8_t fqdn_buf[256];
963 memcpy(fqdn_buf, odata, olen);
964 fqdn_buf[olen++] = 0;
965
966 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
967 hostname_len = strcspn(hostname, ".");
968 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
969 accept_reconf = true;
970 }
971 }
972
973 if (!clid_data || !clid_len || clid_len > 130)
974 goto out;
975
976 struct dhcpv6_assignment *first = NULL;
977 dhcpv6_for_each_option(start, end, otype, olen, odata) {
978 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
979 bool is_na = (otype == DHCPV6_OPT_IA_NA);
980 bool ia_addr_present = false;
981 if (!is_pd && !is_na)
982 continue;
983
984 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
985 size_t ia_response_len = 0;
986 uint8_t reqlen = (is_pd) ? 62 : 128;
987 uint32_t reqhint = 0;
988
989 // Parse request hint for IA-PD
990 if (is_pd) {
991 uint8_t *sdata;
992 uint16_t stype, slen;
993 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
994 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
995 continue;
996
997 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
998 if (p->prefix) {
999 reqlen = p->prefix;
1000 reqhint = ntohl(p->addr.s6_addr32[1]);
1001 if (reqlen > 32 && reqlen <= 64)
1002 reqhint &= (1U << (64 - reqlen)) - 1;
1003 }
1004 }
1005
1006 if (reqlen > 64)
1007 reqlen = 64;
1008 } else if (is_na) {
1009 uint8_t *sdata;
1010 uint16_t stype, slen;
1011 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1012 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1013 continue;
1014
1015 ia_addr_present = true;
1016 }
1017 }
1018
1019 // Find assignment
1020 struct dhcpv6_assignment *c, *a = NULL;
1021 list_for_each_entry(c, &iface->ia_assignments, head) {
1022 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1023 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1024 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1025 (c->iaid == ia->iaid || c->valid_until < now) &&
1026 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1027 a = c;
1028
1029 // Reset state
1030 apply_lease(iface, a, false);
1031 memcpy(a->clid_data, clid_data, clid_len);
1032 a->clid_len = clid_len;
1033 a->iaid = ia->iaid;
1034 a->peer = *addr;
1035 a->reconf_cnt = 0;
1036 a->reconf_sent = 0;
1037 break;
1038 }
1039 }
1040
1041 // Generic message handling
1042 uint16_t status = DHCPV6_STATUS_OK;
1043 if (a && a->managed_size < 0) {
1044 return -1;
1045 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1046 bool assigned = !!a;
1047
1048 if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1049 a = calloc(1, sizeof(*a) + clid_len);
1050 if (a) {
1051 a->clid_len = clid_len;
1052 a->iaid = ia->iaid;
1053 a->length = reqlen;
1054 a->peer = *addr;
1055 a->assigned = reqhint;
1056
1057 if (first)
1058 memcpy(a->key, first->key, sizeof(a->key));
1059 else
1060 odhcpd_urandom(a->key, sizeof(a->key));
1061 memcpy(a->clid_data, clid_data, clid_len);
1062
1063 if (is_pd)
1064 while (!(assigned = assign_pd(iface, a)) &&
1065 !a->managed_size && ++a->length <= 64);
1066 else
1067 assigned = assign_na(iface, a);
1068
1069 if (a->managed_size && !assigned)
1070 return -1;
1071 }
1072 }
1073
1074 if (!assigned || iface->ia_addr_len == 0) { // Set error status
1075 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1076 } else if (assigned && !first) { //
1077 size_t handshake_len = 4;
1078 buf[0] = 0;
1079 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1080 buf[2] = 0;
1081 buf[3] = 0;
1082
1083 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1084 struct dhcpv6_auth_reconfigure auth = {
1085 htons(DHCPV6_OPT_AUTH),
1086 htons(sizeof(auth) - 4),
1087 3, 1, 0,
1088 {htonl(time(NULL)), htonl(++serial)},
1089 1,
1090 {0}
1091 };
1092 memcpy(auth.key, a->key, sizeof(a->key));
1093 memcpy(buf + handshake_len, &auth, sizeof(auth));
1094 handshake_len += sizeof(auth);
1095 }
1096
1097 buf += handshake_len;
1098 buflen -= handshake_len;
1099 response_len += handshake_len;
1100
1101 first = a;
1102 }
1103
1104 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1105
1106 // Was only a solicitation: mark binding for removal
1107 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1108 a->valid_until = 0;
1109 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1110 if (hostname_len > 0) {
1111 a->hostname = realloc(a->hostname, hostname_len + 1);
1112 if (a->hostname) {
1113 memcpy(a->hostname, hostname, hostname_len);
1114 a->hostname[hostname_len] = 0;
1115 }
1116 }
1117 a->accept_reconf = accept_reconf;
1118 apply_lease(iface, a, true);
1119 } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1120 free_dhcpv6_assignment(a);
1121 }
1122 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1123 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1124 hdr->msg_type == DHCPV6_MSG_REBIND ||
1125 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1126 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1127 status = DHCPV6_STATUS_NOBINDING;
1128 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1129 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1130 hdr->msg_type == DHCPV6_MSG_REBIND) {
1131 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1132 if (a)
1133 apply_lease(iface, a, true);
1134 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1135 a->valid_until = 0;
1136 apply_lease(iface, a, false);
1137 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1138 a->clid_len = 0;
1139 a->valid_until = now + 3600; // Block address for 1h
1140 }
1141 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1142 // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1143 status = DHCPV6_STATUS_NOTONLINK;
1144 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1145 notonlink = true;
1146 }
1147
1148 buf += ia_response_len;
1149 buflen -= ia_response_len;
1150 response_len += ia_response_len;
1151 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1152 }
1153
1154 if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1155 response_len + 6 < buflen) {
1156 buf[0] = 0;
1157 buf[1] = DHCPV6_OPT_STATUS;
1158 buf[2] = 0;
1159 buf[3] = 2;
1160 buf[4] = 0;
1161 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1162 response_len += 6;
1163 }
1164
1165 dhcpv6_write_statefile();
1166
1167 out:
1168 return response_len;
1169 }
OpenWrt DHCP Server