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dhcpv6-ia: filter out prefixes having invalid length
[project/odhcpd.git] / src / dhcpv6-ia.c
1 /**
2 * Copyright (C) 2013 Steven Barth <steven@midlink.org>
3 * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License v2 as published by
7 * the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 */
15
16 #include "odhcpd.h"
17 #include "dhcpv6.h"
18 #include "dhcpv4.h"
19 #include "libubox/md5.h"
20 #include "libubox/usock.h"
21
22 #include <time.h>
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <stdio.h>
26 #include <poll.h>
27 #include <alloca.h>
28 #include <resolv.h>
29 #include <limits.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <stdbool.h>
34 #include <arpa/inet.h>
35 #include <sys/timerfd.h>
36
37 #define ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) \
38 ((iface)->managed == RELAYD_MANAGED_NO_AFLAG || (i) == (m) || \
39 (addrs)[(i)].prefix > 64)
40
41 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
42 static void reconf_timer(struct uloop_timeout *event);
43 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
44 static uint32_t serial = 0;
45 static uint8_t statemd5[16];
46
47 int dhcpv6_ia_init(void)
48 {
49 uloop_timeout_set(&reconf_event, 2000);
50 return 0;
51 }
52
53 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
54 {
55 if (!enable && iface->ia_assignments.next) {
56 struct dhcpv6_assignment *c;
57
58 while (!list_empty(&iface->ia_assignments)) {
59 c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
60 free_dhcpv6_assignment(c);
61 }
62 }
63
64 if (enable && iface->dhcpv6 == RELAYD_SERVER) {
65 if (!iface->ia_assignments.next)
66 INIT_LIST_HEAD(&iface->ia_assignments);
67
68 if (list_empty(&iface->ia_assignments)) {
69 struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
70 if (!border) {
71 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
72 return -1;
73 }
74
75 border->length = 64;
76 list_add(&border->head, &iface->ia_assignments);
77 }
78
79 /* Parse static entries */
80 struct lease *lease;
81 list_for_each_entry(lease, &leases, head) {
82 /* Construct entry */
83 size_t duid_len = lease->duid_len ? lease->duid_len : 14;
84 struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
85 if (!a) {
86 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
87 iface->ifname);
88 return -1;
89 }
90
91 if (lease->dhcpv4_leasetime > 0)
92 a->leasetime = lease->dhcpv4_leasetime;
93
94 a->clid_len = duid_len;
95 a->length = 128;
96 if (lease->hostid) {
97 a->assigned = lease->hostid;
98 } else {
99 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
100 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
101 }
102
103 odhcpd_urandom(a->key, sizeof(a->key));
104 memcpy(a->clid_data, lease->duid, lease->duid_len);
105 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
106 /* Static assignment */
107 a->flags |= OAF_STATIC;
108 /* Infinite valid */
109 a->valid_until = 0;
110
111 /* Assign to all interfaces */
112 struct dhcpv6_assignment *c;
113 list_for_each_entry(c, &iface->ia_assignments, head) {
114 if (c->length != 128 || c->assigned > a->assigned) {
115 list_add_tail(&a->head, &c->head);
116 break;
117 } else if (c->assigned == a->assigned)
118 /* Already an assignment with that number */
119 break;
120 }
121
122 if (a->head.next) {
123 if (lease->hostname[0]) {
124 free(a->hostname);
125 a->hostname = strdup(lease->hostname);
126 }
127 } else
128 free_dhcpv6_assignment(a);
129 }
130 }
131 return 0;
132 }
133
134 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
135 {
136 if (c->managed_sock.fd.registered) {
137 ustream_free(&c->managed_sock.stream);
138 close(c->managed_sock.fd.fd);
139 }
140
141 if (c->head.next)
142 list_del(&c->head);
143
144 free(c->managed);
145 free(c->hostname);
146 free(c);
147 }
148
149 static inline bool valid_prefix_length(const struct dhcpv6_assignment *a, const uint8_t prefix_length)
150 {
151 return (a->managed_size || a->length > prefix_length);
152 }
153
154 static inline bool valid_addr(const struct odhcpd_ipaddr *addr, time_t now)
155 {
156 return (addr->prefix <= 96 && addr->preferred > (uint32_t)now);
157 }
158
159 static size_t elect_addr(const struct odhcpd_ipaddr *addrs, const size_t addrlen)
160 {
161 size_t i, m;
162
163 for (i = 0, m = 0; i < addrlen; ++i) {
164 if (addrs[i].preferred > addrs[m].preferred ||
165 (addrs[i].preferred == addrs[m].preferred &&
166 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
167 m = i;
168 }
169
170 return m;
171 }
172
173 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
174 {
175 struct {
176 struct dhcpv6_client_header hdr;
177 uint16_t srvid_type;
178 uint16_t srvid_len;
179 uint16_t duid_type;
180 uint16_t hardware_type;
181 uint8_t mac[6];
182 uint16_t msg_type;
183 uint16_t msg_len;
184 uint8_t msg_id;
185 struct dhcpv6_auth_reconfigure auth;
186 uint16_t clid_type;
187 uint16_t clid_len;
188 uint8_t clid_data[128];
189 } __attribute__((packed)) reconf_msg = {
190 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
191 .srvid_type = htons(DHCPV6_OPT_SERVERID),
192 .srvid_len = htons(10),
193 .duid_type = htons(3),
194 .hardware_type = htons(1),
195 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
196 .msg_len = htons(1),
197 .msg_id = DHCPV6_MSG_RENEW,
198 .auth = {htons(DHCPV6_OPT_AUTH),
199 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
200 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
201 .clid_type = htons(DHCPV6_OPT_CLIENTID),
202 .clid_len = htons(assign->clid_len),
203 .clid_data = {0},
204 };
205
206 odhcpd_get_mac(iface, reconf_msg.mac);
207 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
208 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
209
210 md5_ctx_t md5;
211 uint8_t secretbytes[64];
212 memset(secretbytes, 0, sizeof(secretbytes));
213 memcpy(secretbytes, assign->key, sizeof(assign->key));
214
215 for (size_t i = 0; i < sizeof(secretbytes); ++i)
216 secretbytes[i] ^= 0x36;
217
218 md5_begin(&md5);
219 md5_hash(secretbytes, sizeof(secretbytes), &md5);
220 md5_hash(iov.iov_base, iov.iov_len, &md5);
221 md5_end(reconf_msg.auth.key, &md5);
222
223 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
224 secretbytes[i] ^= 0x36;
225 secretbytes[i] ^= 0x5c;
226 }
227
228 md5_begin(&md5);
229 md5_hash(secretbytes, sizeof(secretbytes), &md5);
230 md5_hash(reconf_msg.auth.key, 16, &md5);
231 md5_end(reconf_msg.auth.key, &md5);
232
233 return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
234 }
235
236 void dhcpv6_write_statefile(void)
237 {
238 md5_ctx_t md5;
239 md5_begin(&md5);
240
241 if (config.dhcp_statefile) {
242 time_t now = odhcpd_time(), wall_time = time(NULL);
243 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
244 if (fd < 0)
245 return;
246
247 lockf(fd, F_LOCK, 0);
248 if (ftruncate(fd, 0) < 0) {}
249
250 FILE *fp = fdopen(fd, "w");
251 if (!fp) {
252 close(fd);
253 return;
254 }
255
256 struct interface *iface;
257 list_for_each_entry(iface, &interfaces, head) {
258 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
259 continue;
260
261 if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
262 struct dhcpv6_assignment *c;
263 list_for_each_entry(c, &iface->ia_assignments, head) {
264 if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
265 continue;
266
267 char ipbuf[INET6_ADDRSTRLEN];
268 char leasebuf[512];
269 char duidbuf[264];
270 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
271
272 /* iface DUID iaid hostname lifetime assigned length [addrs...] */
273 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
274 iface->ifname, duidbuf, ntohl(c->iaid),
275 (c->hostname ? c->hostname : "-"),
276 (c->valid_until > now ?
277 (c->valid_until - now + wall_time) :
278 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
279 c->assigned, (unsigned)c->length);
280
281 struct in6_addr addr;
282 struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
283 size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
284 size_t m = elect_addr(addrs, addrlen);
285
286 for (size_t i = 0; i < addrlen; ++i) {
287 if (!valid_addr(&addrs[i], now) ||
288 (!INFINITE_VALID(c->valid_until) && c->valid_until <= now))
289 continue;
290
291 addr = addrs[i].addr;
292 if (c->length == 128) {
293 if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs))
294 continue;
295
296 addr.s6_addr32[3] = htonl(c->assigned);
297 }
298 else {
299 if (!valid_prefix_length(c, addrs[i].prefix))
300 continue;
301
302 addr.s6_addr32[1] |= htonl(c->assigned);
303 }
304
305 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
306
307 if (c->length == 128 && c->hostname) {
308 fputs(ipbuf, fp);
309
310 char b[256];
311 if (dn_expand(iface->search, iface->search + iface->search_len,
312 iface->search, b, sizeof(b)) > 0)
313 fprintf(fp, "\t%s.%s", c->hostname, b);
314
315 fprintf(fp, "\t%s\n", c->hostname);
316 md5_hash(ipbuf, strlen(ipbuf), &md5);
317 md5_hash(c->hostname, strlen(c->hostname), &md5);
318 }
319
320 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
321 (c->managed_size) ? addrs[i].prefix : c->length);
322 }
323 leasebuf[l - 1] = '\n';
324 fwrite(leasebuf, 1, l, fp);
325 }
326 }
327
328 if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
329 struct dhcpv4_assignment *c;
330 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
331 if (!(c->flags & OAF_BOUND))
332 continue;
333
334 char ipbuf[INET6_ADDRSTRLEN];
335 char leasebuf[512];
336 char duidbuf[16];
337 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
338
339 /* iface DUID iaid hostname lifetime assigned length [addrs...] */
340 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
341 iface->ifname, duidbuf,
342 (c->hostname ? c->hostname : "-"),
343 (c->valid_until > now ?
344 (c->valid_until - now + wall_time) :
345 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
346 c->addr);
347
348 struct in_addr addr = {htonl(c->addr)};
349 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
350
351 if (c->hostname) {
352 fputs(ipbuf, fp);
353
354 char b[256];
355 if (dn_expand(iface->search, iface->search + iface->search_len,
356 iface->search, b, sizeof(b)) > 0)
357 fprintf(fp, "\t%s.%s", c->hostname, b);
358
359 fprintf(fp, "\t%s\n", c->hostname);
360 md5_hash(ipbuf, strlen(ipbuf), &md5);
361 md5_hash(c->hostname, strlen(c->hostname), &md5);
362 }
363
364 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
365 leasebuf[l - 1] = '\n';
366 fwrite(leasebuf, 1, l, fp);
367 }
368 }
369 }
370
371 fclose(fp);
372 }
373
374 uint8_t newmd5[16];
375 md5_end(newmd5, &md5);
376
377 if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
378 memcpy(statemd5, newmd5, sizeof(statemd5));
379 char *argv[2] = {config.dhcp_cb, NULL};
380 if (!vfork()) {
381 execv(argv[0], argv);
382 _exit(128);
383 }
384 }
385 }
386
387
388 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
389 {
390 if (a->length > 64 || a->managed_size < 0)
391 return;
392
393 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
394 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
395
396 for (size_t i = 0; i < addrlen; ++i) {
397 struct in6_addr prefix = addrs[i].addr;
398 prefix.s6_addr32[1] |= htonl(a->assigned);
399 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
400 iface, &a->peer.sin6_addr, 1024, add);
401 }
402 }
403
404 /* More data was received from TCP connection */
405 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
406 {
407 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
408 time_t now = odhcpd_time();
409 bool first = c->managed_size < 0;
410
411 for (;;) {
412 int pending;
413 char *data = ustream_get_read_buf(s, &pending);
414 char *end = memmem(data, pending, "\n\n", 2);
415
416 if (!end)
417 break;
418
419 end += 2;
420 end[-1] = 0;
421
422 c->managed_size = 0;
423 if (c->accept_reconf)
424 c->reconf_cnt = 1;
425
426 char *saveptr;
427 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
428 c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
429 struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
430
431 char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
432 if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
433 continue;
434
435 x = strtok_r(NULL, ",", &saveptr2);
436 if (sscanf(x, "%hhu", &n->prefix) < 1)
437 continue;
438
439 x = strtok_r(NULL, ",", &saveptr2);
440 if (sscanf(x, "%u", &n->preferred) < 1)
441 continue;
442
443 x = strtok_r(NULL, ",", &saveptr2);
444 if (sscanf(x, "%u", &n->valid) < 1)
445 continue;
446
447 if (n->preferred > n->valid)
448 continue;
449
450 if (UINT32_MAX - now < n->preferred)
451 n->preferred = UINT32_MAX;
452 else
453 n->preferred += now;
454
455 if (UINT32_MAX - now < n->valid)
456 n->valid = UINT32_MAX;
457 else
458 n->valid += now;
459
460 n->dprefix = 0;
461
462 ++c->managed_size;
463 }
464
465 ustream_consume(s, end - data);
466 }
467
468 if (first && c->managed_size == 0)
469 free_dhcpv6_assignment(c);
470 else if (first && !(c->flags & OAF_STATIC))
471 c->valid_until = now + 150;
472 }
473
474
475 /* TCP transmission has ended, either because of success or timeout or other error */
476 static void managed_handle_pd_done(struct ustream *s)
477 {
478 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
479
480 if (!(c->flags & OAF_STATIC))
481 c->valid_until = odhcpd_time() + 15;
482
483 c->managed_size = 0;
484
485 if (c->accept_reconf)
486 c->reconf_cnt = 1;
487 }
488
489 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
490 {
491 struct dhcpv6_assignment *c;
492
493 if (iface->dhcpv6_pd_manager[0]) {
494 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
495 if (fd >= 0) {
496 char iaidbuf[298];
497 odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
498
499 assign->managed_sock.stream.notify_read = managed_handle_pd_data;
500 assign->managed_sock.stream.notify_state = managed_handle_pd_done;
501 ustream_fd_init(&assign->managed_sock, fd);
502 ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
503 iaidbuf, assign->iaid, assign->length);
504 ustream_write_pending(&assign->managed_sock.stream);
505 assign->managed_size = -1;
506
507 if (!(assign->flags & OAF_STATIC))
508 assign->valid_until = odhcpd_time() + 15;
509
510 list_add(&assign->head, &iface->ia_assignments);
511
512 /* Wait initial period of up to 250ms for immediate assignment */
513 struct pollfd pfd = { .fd = fd, .events = POLLIN };
514 poll(&pfd, 1, 250);
515 managed_handle_pd_data(&assign->managed_sock.stream, 0);
516
517 if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
518 return true;
519 }
520
521 return false;
522 } else if (iface->ia_addr_len < 1)
523 return false;
524
525 /* Try honoring the hint first */
526 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
527 if (assign->assigned) {
528 list_for_each_entry(c, &iface->ia_assignments, head) {
529 if (c->length == 128 || c->length == 0)
530 continue;
531
532 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
533 list_add_tail(&assign->head, &c->head);
534 apply_lease(iface, assign, true);
535 return true;
536 }
537
538 if (c->assigned != 0)
539 current = (c->assigned + (1 << (64 - c->length)));
540 }
541 }
542
543 /* Fallback to a variable assignment */
544 current = 1;
545 list_for_each_entry(c, &iface->ia_assignments, head) {
546 if (c->length == 128 || c->length == 0)
547 continue;
548
549 current = (current + asize) & (~asize);
550 if (current + asize < c->assigned) {
551 assign->assigned = current;
552 list_add_tail(&assign->head, &c->head);
553 apply_lease(iface, assign, true);
554 return true;
555 }
556
557 if (c->assigned != 0)
558 current = (c->assigned + (1 << (64 - c->length)));
559 }
560
561 return false;
562 }
563
564 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
565 {
566 /* Seed RNG with checksum of DUID */
567 uint32_t seed = 0;
568 for (size_t i = 0; i < assign->clid_len; ++i)
569 seed += assign->clid_data[i];
570 srand(seed);
571
572 /* Try to assign up to 100x */
573 for (size_t i = 0; i < 100; ++i) {
574 uint32_t try;
575 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
576
577 struct dhcpv6_assignment *c;
578 list_for_each_entry(c, &iface->ia_assignments, head) {
579 if (c->length == 0)
580 continue;
581
582 if (c->assigned > try || c->length != 128) {
583 assign->assigned = try;
584 list_add_tail(&assign->head, &c->head);
585 return true;
586 } else if (c->assigned == try)
587 break;
588 }
589 }
590
591 return false;
592 }
593
594 void dhcpv6_ia_preupdate(struct interface *iface)
595 {
596 if (iface->dhcpv6 != RELAYD_SERVER)
597 return;
598
599 struct dhcpv6_assignment *c, *border = list_last_entry(
600 &iface->ia_assignments, struct dhcpv6_assignment, head);
601
602 list_for_each_entry(c, &iface->ia_assignments, head)
603 if (c != border && !iface->managed)
604 apply_lease(iface, c, false);
605 }
606
607 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
608 {
609 if (iface->dhcpv6 != RELAYD_SERVER)
610 return;
611
612 int minprefix = -1;
613 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
614 if (iface->ia_addr[i].preferred > (uint32_t)now &&
615 iface->ia_addr[i].prefix < 64 &&
616 iface->ia_addr[i].prefix > minprefix)
617 minprefix = iface->ia_addr[i].prefix;
618 }
619
620 struct dhcpv6_assignment *border = list_last_entry(
621 &iface->ia_assignments, struct dhcpv6_assignment, head);
622
623 if (minprefix > 32 && minprefix <= 64)
624 border->assigned = 1U << (64 - minprefix);
625 else
626 border->assigned = 0;
627
628 struct list_head reassign = LIST_HEAD_INIT(reassign);
629 struct dhcpv6_assignment *c, *d;
630 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
631 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
632 c->managed_size)
633 continue;
634
635 if (c->length < 128 && c->assigned >= border->assigned && c != border)
636 list_move(&c->head, &reassign);
637 else if (c != border)
638 apply_lease(iface, c, true);
639
640 if (c->accept_reconf && c->reconf_cnt == 0) {
641 c->reconf_cnt = 1;
642 c->reconf_sent = now;
643 send_reconf(iface, c);
644
645 /* Leave all other assignments of that client alone */
646 struct dhcpv6_assignment *a;
647 list_for_each_entry(a, &iface->ia_assignments, head)
648 if (a != c && a->clid_len == c->clid_len &&
649 !memcmp(a->clid_data, c->clid_data, a->clid_len))
650 c->reconf_cnt = INT_MAX;
651 }
652 }
653
654 while (!list_empty(&reassign)) {
655 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
656 list_del(&c->head);
657 if (!assign_pd(iface, c)) {
658 c->assigned = 0;
659 list_add(&c->head, &iface->ia_assignments);
660 }
661 }
662
663 dhcpv6_write_statefile();
664 }
665
666 static void reconf_timer(struct uloop_timeout *event)
667 {
668 time_t now = odhcpd_time();
669 struct interface *iface;
670 list_for_each_entry(iface, &interfaces, head) {
671 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
672 continue;
673
674 struct dhcpv6_assignment *a, *n;
675 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
676 if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
677 if ((a->length < 128 && a->clid_len > 0) ||
678 (a->length == 128 && a->clid_len == 0))
679 free_dhcpv6_assignment(a);
680
681 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
682 now > a->reconf_sent + (1 << a->reconf_cnt)) {
683 ++a->reconf_cnt;
684 a->reconf_sent = now;
685 send_reconf(iface, a);
686 }
687 }
688 }
689 uloop_timeout_set(event, 2000);
690 }
691
692 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
693 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
694 struct interface *iface, bool request)
695 {
696 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
697 return 0;
698
699 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
700 size_t datalen = sizeof(out);
701 time_t now = odhcpd_time();
702
703 if (status) {
704 struct __attribute__((packed)) {
705 uint16_t type;
706 uint16_t len;
707 uint16_t value;
708 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
709 htons(status)};
710
711 memcpy(buf + datalen, &stat, sizeof(stat));
712 datalen += sizeof(stat);
713 } else {
714 if (a) {
715 uint32_t leasetime;
716 if (a->leasetime > 0)
717 leasetime = a->leasetime;
718 else
719 leasetime = iface->dhcpv4_leasetime;
720
721 if (leasetime == 0)
722 leasetime = 3600;
723 else if (leasetime < 60)
724 leasetime = 60;
725
726 uint32_t pref = leasetime;
727 uint32_t valid = leasetime;
728
729 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
730 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
731 size_t m = elect_addr(addrs, addrlen);
732
733 for (size_t i = 0; i < addrlen; ++i) {
734 uint32_t prefix_pref = addrs[i].preferred;
735 uint32_t prefix_valid = addrs[i].valid;
736
737 if (!valid_addr(&addrs[i], now))
738 continue;
739
740 if (prefix_pref != UINT32_MAX)
741 prefix_pref -= now;
742
743 if (prefix_valid != UINT32_MAX)
744 prefix_valid -= now;
745
746 if (a->length < 128) {
747 struct dhcpv6_ia_prefix p = {
748 .type = htons(DHCPV6_OPT_IA_PREFIX),
749 .len = htons(sizeof(p) - 4),
750 .preferred = htonl(prefix_pref),
751 .valid = htonl(prefix_valid),
752 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
753 .addr = addrs[i].addr
754 };
755 p.addr.s6_addr32[1] |= htonl(a->assigned);
756
757 size_t entrlen = sizeof(p) - 4;
758
759 if (datalen + entrlen + 4 > buflen ||
760 (a->assigned == 0 && a->managed_size == 0) ||
761 !valid_prefix_length(a, addrs[i].prefix))
762 continue;
763
764 memcpy(buf + datalen, &p, sizeof(p));
765 datalen += entrlen + 4;
766 } else {
767 struct dhcpv6_ia_addr n = {
768 .type = htons(DHCPV6_OPT_IA_ADDR),
769 .len = htons(sizeof(n) - 4),
770 .addr = addrs[i].addr,
771 .preferred = htonl(prefix_pref),
772 .valid = htonl(prefix_valid)
773 };
774 n.addr.s6_addr32[3] = htonl(a->assigned);
775 size_t entrlen = sizeof(n) - 4;
776
777 if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
778 a->assigned == 0 ||
779 datalen + entrlen + 4 > buflen)
780 continue;
781
782 memcpy(buf + datalen, &n, sizeof(n));
783 datalen += entrlen + 4;
784 }
785
786 /* Calculate T1 / T2 based on non-deprecated addresses */
787 if (prefix_pref > 0) {
788 if (prefix_pref < pref)
789 pref = prefix_pref;
790
791 if (prefix_valid < valid)
792 valid = prefix_valid;
793 }
794 }
795
796 if (!INFINITE_VALID(a->valid_until))
797 /* UINT32_MAX is considered as infinite leasetime */
798 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
799
800 out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
801 out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
802
803 if (!out.t1)
804 out.t1 = htonl(1);
805
806 if (!out.t2)
807 out.t2 = htonl(1);
808 }
809
810 if (!request) {
811 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
812 uint16_t otype, olen;
813 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
814 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
815 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
816 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
817 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
818 continue;
819
820 bool found = false;
821 if (a) {
822 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
823 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
824
825 for (size_t i = 0; i < addrlen; ++i) {
826 if (!valid_addr(&addrs[i], now))
827 continue;
828
829 struct in6_addr addr = addrs[i].addr;
830 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
831 addr.s6_addr32[1] |= htonl(a->assigned);
832
833 if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
834 p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
835 found = true;
836 } else {
837 addr.s6_addr32[3] = htonl(a->assigned);
838
839 if (!memcmp(&n->addr, &addr, sizeof(addr)))
840 found = true;
841 }
842 }
843 }
844
845 if (!found) {
846 if (otype == DHCPV6_OPT_IA_PREFIX) {
847 struct dhcpv6_ia_prefix inv = {
848 .type = htons(DHCPV6_OPT_IA_PREFIX),
849 .len = htons(sizeof(inv) - 4),
850 .preferred = 0,
851 .valid = 0,
852 .prefix = p->prefix,
853 .addr = p->addr
854 };
855
856 if (datalen + sizeof(inv) > buflen)
857 continue;
858
859 memcpy(buf + datalen, &inv, sizeof(inv));
860 datalen += sizeof(inv);
861 } else {
862 struct dhcpv6_ia_addr inv = {
863 .type = htons(DHCPV6_OPT_IA_ADDR),
864 .len = htons(sizeof(inv) - 4),
865 .addr = n->addr,
866 .preferred = 0,
867 .valid = 0
868 };
869
870 if (datalen + sizeof(inv) > buflen)
871 continue;
872
873 memcpy(buf + datalen, &inv, sizeof(inv));
874 datalen += sizeof(inv);
875 }
876 }
877 }
878 }
879 }
880
881 out.len = htons(datalen - 4);
882 memcpy(buf, &out, sizeof(out));
883 return datalen;
884 }
885
886 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
887 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
888 {
889 const char *type = "UNKNOWN";
890 const char *status = "UNKNOWN";
891
892 if (msgtype == DHCPV6_MSG_RENEW)
893 return;
894
895 switch (msgtype) {
896 case DHCPV6_MSG_SOLICIT:
897 type = "SOLICIT";
898 break;
899 case DHCPV6_MSG_REQUEST:
900 type = "REQUEST";
901 break;
902 case DHCPV6_MSG_CONFIRM:
903 type = "CONFIRM";
904 break;
905 case DHCPV6_MSG_RENEW:
906 type = "RENEW";
907 break;
908 case DHCPV6_MSG_REBIND:
909 type = "REBIND";
910 break;
911 case DHCPV6_MSG_RELEASE:
912 type = "RELEASE";
913 break;
914 case DHCPV6_MSG_DECLINE:
915 type = "DECLINE";
916 break;
917 }
918
919 switch (code) {
920 case DHCPV6_STATUS_OK:
921 status = "ok";
922 break;
923 case DHCPV6_STATUS_NOADDRSAVAIL:
924 status = "no addresses available";
925 break;
926 case DHCPV6_STATUS_NOBINDING:
927 status = "no binding";
928 break;
929 case DHCPV6_STATUS_NOTONLINK:
930 status = "not on-link";
931 break;
932 case DHCPV6_STATUS_NOPREFIXAVAIL:
933 status = "no prefix available";
934 break;
935 }
936
937 char leasebuf[256] = "";
938
939 if (a) {
940 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
941 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
942 size_t lbsize = 0;
943 size_t m = elect_addr(addrs, addrlen);
944 char addrbuf[INET6_ADDRSTRLEN];
945
946 for (size_t i = 0; i < addrlen; ++i) {
947 if (!valid_addr(&addrs[i], now))
948 continue;
949
950 struct in6_addr addr = addrs[i].addr;
951 int prefix = a->managed ? addrs[i].prefix : a->length;
952 if (prefix == 128) {
953 if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
954 a->assigned == 0)
955 continue;
956
957 addr.s6_addr32[3] = htonl(a->assigned);
958 }
959 else {
960 if (!valid_prefix_length(a, addrs[i].prefix))
961 continue;
962
963 addr.s6_addr32[1] |= htonl(a->assigned);
964 }
965
966 inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
967 lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
968 }
969 }
970
971 syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
972 duidbuf, iface->ifname, status, leasebuf);
973 }
974
975 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
976 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
977 {
978 time_t now = odhcpd_time();
979 size_t response_len = 0;
980 const struct dhcpv6_client_header *hdr = data;
981 uint8_t *start = (uint8_t*)&hdr[1], *odata;
982 uint16_t otype, olen;
983 /* Find and parse client-id and hostname */
984 bool accept_reconf = false;
985 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
986 char hostname[256];
987 size_t hostname_len = 0;
988 bool notonlink = false;
989 char duidbuf[261];
990
991 dhcpv6_for_each_option(start, end, otype, olen, odata) {
992 if (otype == DHCPV6_OPT_CLIENTID) {
993 clid_data = odata;
994 clid_len = olen;
995
996 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
997 memcpy(mac, &odata[8], sizeof(mac));
998 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
999 memcpy(mac, &odata[4], sizeof(mac));
1000
1001 if (olen <= 130)
1002 odhcpd_hexlify(duidbuf, odata, olen);
1003 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
1004 uint8_t fqdn_buf[256];
1005 memcpy(fqdn_buf, odata, olen);
1006 fqdn_buf[olen++] = 0;
1007
1008 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
1009 hostname_len = strcspn(hostname, ".");
1010 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT)
1011 accept_reconf = true;
1012 }
1013
1014 if (!clid_data || !clid_len || clid_len > 130)
1015 goto out;
1016
1017 struct dhcpv6_assignment *first = NULL;
1018 dhcpv6_for_each_option(start, end, otype, olen, odata) {
1019 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1020 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1021 bool ia_addr_present = false;
1022 if (!is_pd && !is_na)
1023 continue;
1024
1025 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1026 size_t ia_response_len = 0;
1027 uint8_t reqlen = (is_pd) ? 62 : 128;
1028 uint32_t reqhint = 0;
1029
1030 /* Parse request hint for IA-PD */
1031 if (is_pd) {
1032 uint8_t *sdata;
1033 uint16_t stype, slen;
1034 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1035 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1036 continue;
1037
1038 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1039 if (p->prefix) {
1040 reqlen = p->prefix;
1041 reqhint = ntohl(p->addr.s6_addr32[1]);
1042 if (reqlen > 32 && reqlen <= 64)
1043 reqhint &= (1U << (64 - reqlen)) - 1;
1044 }
1045 }
1046
1047 if (reqlen > 64)
1048 reqlen = 64;
1049 } else if (is_na) {
1050 uint8_t *sdata;
1051 uint16_t stype, slen;
1052 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1053 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1054 continue;
1055
1056 ia_addr_present = true;
1057 }
1058 }
1059
1060 /* Find assignment */
1061 struct dhcpv6_assignment *c, *a = NULL;
1062 list_for_each_entry(c, &iface->ia_assignments, head) {
1063 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1064 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1065 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1066 (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1067 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1068 a = c;
1069
1070 /* Reset state */
1071 apply_lease(iface, a, false);
1072 memcpy(a->clid_data, clid_data, clid_len);
1073 a->clid_len = clid_len;
1074 a->iaid = ia->iaid;
1075 a->peer = *addr;
1076 a->reconf_cnt = 0;
1077 a->reconf_sent = 0;
1078 break;
1079 }
1080 }
1081
1082 /* Generic message handling */
1083 uint16_t status = DHCPV6_STATUS_OK;
1084 if (a && a->managed_size < 0)
1085 return -1;
1086
1087 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1088 bool assigned = !!a;
1089
1090 if (!a && !iface->no_dynamic_dhcp) {
1091 /* Create new binding */
1092 a = calloc(1, sizeof(*a) + clid_len);
1093 if (a) {
1094 a->clid_len = clid_len;
1095 a->iaid = ia->iaid;
1096 a->length = reqlen;
1097 a->peer = *addr;
1098 a->assigned = reqhint;
1099 /* Set valid time to current time indicating */
1100 /* assignment is not having infinite lifetime */
1101 a->valid_until = now;
1102
1103 if (first)
1104 memcpy(a->key, first->key, sizeof(a->key));
1105 else
1106 odhcpd_urandom(a->key, sizeof(a->key));
1107 memcpy(a->clid_data, clid_data, clid_len);
1108
1109 if (is_pd)
1110 while (!(assigned = assign_pd(iface, a)) &&
1111 !a->managed_size && ++a->length <= 64);
1112 else
1113 assigned = assign_na(iface, a);
1114
1115 if (a->managed_size && !assigned)
1116 return -1;
1117 }
1118 }
1119
1120 if (!assigned || iface->ia_addr_len == 0)
1121 /* Set error status */
1122 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1123 else if (assigned && !first) {
1124 size_t handshake_len = 4;
1125 buf[0] = 0;
1126 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1127 buf[2] = 0;
1128 buf[3] = 0;
1129
1130 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1131 struct dhcpv6_auth_reconfigure auth = {
1132 htons(DHCPV6_OPT_AUTH),
1133 htons(sizeof(auth) - 4),
1134 3, 1, 0,
1135 {htonl(time(NULL)), htonl(++serial)},
1136 1,
1137 {0}
1138 };
1139 memcpy(auth.key, a->key, sizeof(a->key));
1140 memcpy(buf + handshake_len, &auth, sizeof(auth));
1141 handshake_len += sizeof(auth);
1142 }
1143
1144 buf += handshake_len;
1145 buflen -= handshake_len;
1146 response_len += handshake_len;
1147
1148 first = a;
1149 }
1150
1151 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1152
1153 /* Was only a solicitation: mark binding for removal */
1154 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1155 a->flags &= ~OAF_BOUND;
1156
1157 if (!(a->flags & OAF_STATIC))
1158 a->valid_until = now;
1159 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1160 if (hostname_len > 0) {
1161 a->hostname = realloc(a->hostname, hostname_len + 1);
1162 if (a->hostname) {
1163 memcpy(a->hostname, hostname, hostname_len);
1164 a->hostname[hostname_len] = 0;
1165 }
1166 }
1167 a->accept_reconf = accept_reconf;
1168 a->flags |= OAF_BOUND;
1169 apply_lease(iface, a, true);
1170 } else if (!assigned && a && a->managed_size == 0) {
1171 /* Cleanup failed assignment */
1172 free_dhcpv6_assignment(a);
1173 a = NULL;
1174 }
1175 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1176 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1177 hdr->msg_type == DHCPV6_MSG_REBIND ||
1178 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1179 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1180 status = DHCPV6_STATUS_NOBINDING;
1181 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1182 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1183 hdr->msg_type == DHCPV6_MSG_REBIND) {
1184 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1185 if (a) {
1186 a->flags |= OAF_BOUND;
1187 apply_lease(iface, a, true);
1188 }
1189 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1190 if (!(a->flags & OAF_STATIC))
1191 a->valid_until = now - 1;
1192
1193 a->flags &= ~OAF_BOUND;
1194 apply_lease(iface, a, false);
1195 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1196 a->flags &= ~OAF_BOUND;
1197
1198 if (!(a->flags & OAF_STATIC)) {
1199 a->clid_len = 0;
1200 a->valid_until = now + 3600; /* Block address for 1h */
1201 }
1202 }
1203 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1204 /* Send NOTONLINK for CONFIRM with addr present so that clients restart connection */
1205 status = DHCPV6_STATUS_NOTONLINK;
1206 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1207 notonlink = true;
1208 }
1209
1210 buf += ia_response_len;
1211 buflen -= ia_response_len;
1212 response_len += ia_response_len;
1213 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1214 }
1215
1216 if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1217 response_len + 6 < buflen) {
1218 buf[0] = 0;
1219 buf[1] = DHCPV6_OPT_STATUS;
1220 buf[2] = 0;
1221 buf[3] = 2;
1222 buf[4] = 0;
1223 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1224 response_len += 6;
1225 }
1226
1227 dhcpv6_write_statefile();
1228
1229 out:
1230 return response_len;
1231 }
OpenWrt DHCP Server