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