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derive ipv6 static lease from ipv4 if no hostid is given
[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
20 #include <time.h>
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <alloca.h>
24 #include <resolv.h>
25 #include <limits.h>
26 #include <stdlib.h>
27 #include <unistd.h>
28 #include <arpa/inet.h>
29 #include <sys/timerfd.h>
30
31
32 static void update(struct interface *iface);
33 static void reconf_timer(struct uloop_timeout *event);
34 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
35 static int socket_fd = -1;
36 static uint32_t serial = 0;
37
38
39 int dhcpv6_ia_init(int dhcpv6_socket)
40 {
41 socket_fd = dhcpv6_socket;
42 uloop_timeout_set(&reconf_event, 2000);
43 return 0;
44 }
45
46
47 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
48 {
49 if (!enable && iface->ia_assignments.next) {
50 struct dhcpv6_assignment *c;
51 while (!list_empty(&iface->ia_assignments)) {
52 c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
53 list_del(&c->head);
54 free(c->hostname);
55 free(c->classes);
56 free(c);
57 }
58 }
59
60 if (iface->dhcpv6 == RELAYD_SERVER) {
61 if (!iface->ia_assignments.next)
62 INIT_LIST_HEAD(&iface->ia_assignments);
63
64 if (list_empty(&iface->ia_assignments)) {
65 struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
66 if (!border) {
67 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
68 return -1;
69 }
70
71 border->length = 64;
72 list_add(&border->head, &iface->ia_assignments);
73 }
74
75 update(iface);
76
77 // Parse static entries
78 struct lease *lease;
79 list_for_each_entry(lease, &leases, head) {
80 // Construct entry
81 struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
82 if (!a) {
83 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
84 iface->ifname);
85 return -1;
86 }
87
88 a->clid_len = lease->duid_len;
89 a->length = 128;
90 if (lease->hostid) {
91 a->assigned = lease->hostid;
92 } else {
93 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
94 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
95 }
96 odhcpd_urandom(a->key, sizeof(a->key));
97 memcpy(a->clid_data, lease->duid, a->clid_len);
98 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
99
100 // Assign to all interfaces
101 struct dhcpv6_assignment *c;
102 list_for_each_entry(c, &iface->ia_assignments, head) {
103 if (c->length != 128 || c->assigned > a->assigned) {
104 list_add_tail(&a->head, &c->head);
105 } else if (c->assigned == a->assigned) {
106 // Already an assignment with that number
107 break;
108 }
109 }
110
111 if (a->head.next) {
112 if (lease->hostname[0]) {
113 free(a->hostname);
114 a->hostname = strdup(lease->hostname);
115 }
116 } else {
117 free(a->classes);
118 free(a->hostname);
119 free(a);
120 }
121 }
122 }
123 return 0;
124 }
125
126
127 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
128 {
129 struct {
130 struct dhcpv6_client_header hdr;
131 uint16_t srvid_type;
132 uint16_t srvid_len;
133 uint16_t duid_type;
134 uint16_t hardware_type;
135 uint8_t mac[6];
136 uint16_t msg_type;
137 uint16_t msg_len;
138 uint8_t msg_id;
139 struct dhcpv6_auth_reconfigure auth;
140 uint16_t clid_type;
141 uint16_t clid_len;
142 uint8_t clid_data[128];
143 } __attribute__((packed)) reconf_msg = {
144 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
145 .srvid_type = htons(DHCPV6_OPT_SERVERID),
146 .srvid_len = htons(10),
147 .duid_type = htons(3),
148 .hardware_type = htons(1),
149 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
150 .msg_len = htons(1),
151 .msg_id = DHCPV6_MSG_RENEW,
152 .auth = {htons(DHCPV6_OPT_AUTH),
153 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
154 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
155 .clid_type = htons(DHCPV6_OPT_CLIENTID),
156 .clid_len = htons(assign->clid_len),
157 .clid_data = {0},
158 };
159
160 odhcpd_get_mac(iface, reconf_msg.mac);
161 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
162 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
163
164 md5_ctx_t md5;
165 uint8_t secretbytes[16];
166 memcpy(secretbytes, assign->key, sizeof(secretbytes));
167
168 for (size_t i = 0; i < sizeof(secretbytes); ++i)
169 secretbytes[i] ^= 0x36;
170
171 md5_begin(&md5);
172 md5_hash(secretbytes, sizeof(secretbytes), &md5);
173 md5_hash(iov.iov_base, iov.iov_len, &md5);
174 md5_end(reconf_msg.auth.key, &md5);
175
176 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
177 secretbytes[i] ^= 0x36;
178 secretbytes[i] ^= 0x5c;
179 }
180
181 md5_begin(&md5);
182 md5_hash(secretbytes, sizeof(secretbytes), &md5);
183 md5_hash(reconf_msg.auth.key, 16, &md5);
184 md5_end(reconf_msg.auth.key, &md5);
185
186 return odhcpd_send(socket_fd, &assign->peer, &iov, 1, iface);
187 }
188
189
190 void dhcpv6_write_statefile(void)
191 {
192 if (config.dhcp_statefile) {
193 time_t now = odhcpd_time(), wall_time = time(NULL);
194 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
195 if (fd < 0)
196 return;
197
198 lockf(fd, F_LOCK, 0);
199 ftruncate(fd, 0);
200
201 FILE *fp = fdopen(fd, "w");
202 if (!fp) {
203 close(fd);
204 return;
205 }
206
207 struct interface *iface;
208 list_for_each_entry(iface, &interfaces, head) {
209 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
210 continue;
211
212 if (iface->dhcpv6 == RELAYD_SERVER) {
213 struct dhcpv6_assignment *c;
214 list_for_each_entry(c, &iface->ia_assignments, head) {
215 if (c->clid_len == 0)
216 continue;
217
218 char ipbuf[INET6_ADDRSTRLEN];
219 char leasebuf[512];
220 char duidbuf[264];
221 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
222
223 // iface DUID iaid hostname lifetime assigned length [addrs...]
224 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
225 iface->ifname, duidbuf, ntohl(c->iaid),
226 (c->hostname ? c->hostname : "-"),
227 (unsigned)(c->valid_until > now ?
228 (c->valid_until - now + wall_time) : 0),
229 c->assigned, (unsigned)c->length);
230
231 struct in6_addr addr;
232 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
233 if (iface->ia_addr[i].prefix > 64)
234 continue;
235
236 addr = iface->ia_addr[i].addr;
237 if (c->length == 128)
238 addr.s6_addr32[3] = htonl(c->assigned);
239 else
240 addr.s6_addr32[1] |= htonl(c->assigned);
241 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
242
243 if (c->length == 128 && c->hostname && i == 0)
244 fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
245
246 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length);
247 }
248 leasebuf[l - 1] = '\n';
249 fwrite(leasebuf, 1, l, fp);
250 }
251 }
252
253 if (iface->dhcpv4 == RELAYD_SERVER) {
254 struct dhcpv4_assignment *c;
255 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
256 char ipbuf[INET6_ADDRSTRLEN];
257 char leasebuf[512];
258 char duidbuf[16];
259 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
260
261 // iface DUID iaid hostname lifetime assigned length [addrs...]
262 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
263 iface->ifname, duidbuf,
264 (c->hostname ? c->hostname : "-"),
265 (unsigned)(c->valid_until > now ?
266 (c->valid_until - now + wall_time) : 0),
267 c->addr);
268
269 struct in_addr addr = {htonl(c->addr)};
270 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
271
272 if (c->hostname[0])
273 fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
274
275 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
276 leasebuf[l - 1] = '\n';
277 fwrite(leasebuf, 1, l, fp);
278 }
279 }
280 }
281
282 fclose(fp);
283 }
284
285 if (config.dhcp_cb) {
286 char *argv[2] = {config.dhcp_cb, NULL};
287 if (!vfork()) {
288 execv(argv[0], argv);
289 _exit(128);
290 }
291 }
292 }
293
294
295 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
296 {
297 if (a->length > 64)
298 return;
299
300 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
301 struct in6_addr prefix = iface->ia_addr[i].addr;
302 prefix.s6_addr32[1] |= htonl(a->assigned);
303 odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add);
304 }
305 }
306
307
308 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
309 {
310 struct dhcpv6_assignment *c;
311 if (iface->ia_addr_len < 1)
312 return false;
313
314 // Try honoring the hint first
315 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
316 if (assign->assigned) {
317 list_for_each_entry(c, &iface->ia_assignments, head) {
318 if (c->length == 128)
319 continue;
320
321 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
322 list_add_tail(&assign->head, &c->head);
323 apply_lease(iface, assign, true);
324 return true;
325 }
326
327 if (c->assigned != 0)
328 current = (c->assigned + (1 << (64 - c->length)));
329 }
330 }
331
332 // Fallback to a variable assignment
333 current = 1;
334 list_for_each_entry(c, &iface->ia_assignments, head) {
335 if (c->length == 128)
336 continue;
337
338 current = (current + asize) & (~asize);
339 if (current + asize < c->assigned) {
340 assign->assigned = current;
341 list_add_tail(&assign->head, &c->head);
342 apply_lease(iface, assign, true);
343 return true;
344 }
345
346 if (c->assigned != 0)
347 current = (c->assigned + (1 << (64 - c->length)));
348 }
349
350 return false;
351 }
352
353
354 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
355 {
356 bool match = false;
357 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
358 if (!iface->ia_addr[i].has_class) {
359 match = true;
360 continue;
361 } else if (assign->classes_cnt) {
362 for (size_t j = 0; j < assign->classes_cnt; ++j)
363 if (assign->classes[j] == iface->ia_addr[i].class)
364 match = true;
365 } else if (assign->all_class) {
366 match = true;
367 }
368 }
369
370 if (!match)
371 return false;
372
373 // Seed RNG with checksum of DUID
374 uint32_t seed = 0;
375 for (size_t i = 0; i < assign->clid_len; ++i)
376 seed += assign->clid_data[i];
377 srand(seed);
378
379 // Try to assign up to 100x
380 for (size_t i = 0; i < 100; ++i) {
381 uint32_t try;
382 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
383
384 struct dhcpv6_assignment *c;
385 list_for_each_entry(c, &iface->ia_assignments, head) {
386 if (c->assigned > try || c->length != 128) {
387 assign->assigned = try;
388 list_add_tail(&assign->head, &c->head);
389 return true;
390 } else if (c->assigned == try) {
391 break;
392 }
393 }
394 }
395
396 return false;
397 }
398
399
400 static int prefixcmp(const void *va, const void *vb)
401 {
402 const struct odhcpd_ipaddr *a = va, *b = vb;
403 uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
404 uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
405 return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
406 }
407
408
409 static void update(struct interface *iface)
410 {
411 struct odhcpd_ipaddr addr[8];
412 memset(addr, 0, sizeof(addr));
413 int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
414
415 if (len < 0)
416 return;
417
418 qsort(addr, len, sizeof(*addr), prefixcmp);
419
420 time_t now = odhcpd_time();
421 int minprefix = -1;
422
423 for (int i = 0; i < len; ++i) {
424 if (addr[i].prefix > minprefix)
425 minprefix = addr[i].prefix;
426
427 addr[i].addr.s6_addr32[2] = 0;
428 addr[i].addr.s6_addr32[3] = 0;
429
430 if (addr[i].preferred < UINT32_MAX - now)
431 addr[i].preferred += now;
432
433 if (addr[i].valid < UINT32_MAX - now)
434 addr[i].valid += now;
435 }
436
437 struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
438 border->assigned = 1 << (64 - minprefix);
439
440 bool change = len != (int)iface->ia_addr_len;
441 for (int i = 0; !change && i < len; ++i)
442 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
443 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
444 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
445 (addr[i].valid > (uint32_t)now + 7200) !=
446 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
447 change = true;
448
449 if (change) {
450 struct dhcpv6_assignment *c;
451 list_for_each_entry(c, &iface->ia_assignments, head)
452 if (c != border)
453 apply_lease(iface, c, false);
454 }
455
456 memcpy(iface->ia_addr, addr, len * sizeof(*addr));
457 iface->ia_addr_len = len;
458
459 if (change) { // Addresses / prefixes have changed
460 struct list_head reassign = LIST_HEAD_INIT(reassign);
461 struct dhcpv6_assignment *c, *d;
462 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
463 if (c->clid_len == 0 || c->valid_until < now)
464 continue;
465
466 if (c->length < 128 && c->assigned >= border->assigned && c != border)
467 list_move(&c->head, &reassign);
468 else if (c != border)
469 apply_lease(iface, c, true);
470
471 if (c->accept_reconf && c->reconf_cnt == 0) {
472 c->reconf_cnt = 1;
473 c->reconf_sent = now;
474 send_reconf(iface, c);
475
476 // Leave all other assignments of that client alone
477 struct dhcpv6_assignment *a;
478 list_for_each_entry(a, &iface->ia_assignments, head)
479 if (a != c && a->clid_len == c->clid_len &&
480 !memcmp(a->clid_data, c->clid_data, a->clid_len))
481 c->reconf_cnt = INT_MAX;
482 }
483 }
484
485 while (!list_empty(&reassign)) {
486 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
487 list_del(&c->head);
488 if (!assign_pd(iface, c)) {
489 c->assigned = 0;
490 list_add(&c->head, &iface->ia_assignments);
491 }
492 }
493
494 dhcpv6_write_statefile();
495 }
496 }
497
498
499 static void reconf_timer(struct uloop_timeout *event)
500 {
501 time_t now = odhcpd_time();
502 struct interface *iface;
503 list_for_each_entry(iface, &interfaces, head) {
504 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
505 continue;
506
507 struct dhcpv6_assignment *a, *n;
508 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
509 if (a->valid_until < now) {
510 if ((a->length < 128 && a->clid_len > 0) ||
511 (a->length == 128 && a->clid_len == 0)) {
512 list_del(&a->head);
513 free(a->classes);
514 free(a->hostname);
515 free(a);
516 }
517 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
518 now > a->reconf_sent + (1 << a->reconf_cnt)) {
519 ++a->reconf_cnt;
520 a->reconf_sent = now;
521 send_reconf(iface, a);
522 }
523 }
524
525 if (iface->ia_reconf) {
526 update(iface);
527 iface->ia_reconf = false;
528 }
529 }
530
531 uloop_timeout_set(event, 2000);
532 }
533
534
535 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
536 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
537 struct interface *iface, bool request)
538 {
539 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
540 return 0;
541
542 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
543 size_t datalen = sizeof(out);
544 time_t now = odhcpd_time();
545
546 if (status) {
547 struct __attribute__((packed)) {
548 uint16_t type;
549 uint16_t len;
550 uint16_t value;
551 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
552 htons(status)};
553
554 memcpy(buf + datalen, &stat, sizeof(stat));
555 datalen += sizeof(stat);
556 } else {
557 if (a) {
558 uint32_t pref = 3600;
559 uint32_t valid = 3600;
560
561 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
562 bool match = true;
563 if (iface->ia_addr[i].has_class) {
564 match = false;
565 if (a->classes_cnt) {
566 for (size_t j = 0; j < a->classes_cnt; ++j)
567 if (a->classes[j] == iface->ia_addr[i].class)
568 match = true;
569 } else if (a->all_class) {
570 match = true;
571 }
572 }
573
574 if (!match)
575 continue;
576
577 uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
578 uint32_t prefix_valid = iface->ia_addr[i].valid - now;
579
580 if (iface->ia_addr[i].prefix > 64 ||
581 iface->ia_addr[i].preferred <= (uint32_t)now)
582 continue;
583
584 if (prefix_pref > 86400)
585 prefix_pref = 86400;
586
587 if (prefix_valid > 86400)
588 prefix_valid = 86400;
589
590 #ifdef DHCPV6_OPT_PREFIX_CLASS
591 struct {
592 uint16_t code;
593 uint16_t length;
594 uint16_t class;
595 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
596 htons(2), htons(iface->ia_addr[i].class)};
597 #endif
598
599 if (a->length < 128) {
600 struct dhcpv6_ia_prefix p = {
601 .type = htons(DHCPV6_OPT_IA_PREFIX),
602 .len = htons(sizeof(p) - 4),
603 .preferred = htonl(prefix_pref),
604 .valid = htonl(prefix_valid),
605 .prefix = a->length,
606 .addr = iface->ia_addr[i].addr
607 };
608 p.addr.s6_addr32[1] |= htonl(a->assigned);
609 size_t entrlen = sizeof(p) - 4;
610
611 #ifdef DHCPV6_OPT_PREFIX_CLASS
612 if (iface->ia_addr[i].has_class) {
613 entrlen += sizeof(pclass);
614 p.len = htons(entrlen);
615 }
616 #endif
617
618 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
619 continue;
620
621 memcpy(buf + datalen, &p, sizeof(p));
622 #ifdef DHCPV6_OPT_PREFIX_CLASS
623 memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
624 #endif
625 datalen += entrlen + 4;
626 } else {
627 struct dhcpv6_ia_addr n = {
628 .type = htons(DHCPV6_OPT_IA_ADDR),
629 .len = htons(sizeof(n) - 4),
630 .addr = iface->ia_addr[i].addr,
631 .preferred = htonl(prefix_pref),
632 .valid = htonl(prefix_valid)
633 };
634 n.addr.s6_addr32[3] = htonl(a->assigned);
635 size_t entrlen = sizeof(n) - 4;
636
637 #ifdef DHCPV6_OPT_PREFIX_CLASS
638 if (iface->ia_addr[i].has_class) {
639 entrlen += sizeof(pclass);
640 n.len = htons(entrlen);
641 }
642 #endif
643
644 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
645 continue;
646
647 memcpy(buf + datalen, &n, sizeof(n));
648 #ifdef DHCPV6_OPT_PREFIX_CLASS
649 memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
650 #endif
651 datalen += entrlen + 4;
652 }
653
654 // Calculate T1 / T2 based on non-deprecated addresses
655 if (prefix_pref > 0) {
656 if (prefix_pref < pref)
657 pref = prefix_pref;
658
659 if (prefix_valid < valid)
660 valid = prefix_valid;
661 }
662 }
663
664 a->valid_until = valid + now;
665 out.t1 = htonl(pref * 5 / 10);
666 out.t2 = htonl(pref * 8 / 10);
667
668 if (!out.t1)
669 out.t1 = htonl(1);
670
671 if (!out.t2)
672 out.t2 = htonl(1);
673 }
674
675 if (!request) {
676 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
677 uint16_t otype, olen;
678 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
679 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
680 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
681 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
682 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
683 continue;
684
685 bool found = false;
686 if (a) {
687 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
688 if (iface->ia_addr[i].prefix > 64 ||
689 iface->ia_addr[i].preferred <= (uint32_t)now)
690 continue;
691
692 struct in6_addr addr = iface->ia_addr[i].addr;
693 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
694 addr.s6_addr32[1] |= htonl(a->assigned);
695
696 if (IN6_ARE_ADDR_EQUAL(&p->addr, &addr) &&
697 p->prefix == a->length)
698 found = true;
699 } else {
700 addr.s6_addr32[3] = htonl(a->assigned);
701
702 if (IN6_ARE_ADDR_EQUAL(&n->addr, &addr))
703 found = true;
704 }
705 }
706 }
707
708 if (!found) {
709 if (otype == DHCPV6_OPT_IA_PREFIX) {
710 struct dhcpv6_ia_prefix inv = {
711 .type = htons(DHCPV6_OPT_IA_PREFIX),
712 .len = htons(sizeof(inv) - 4),
713 .preferred = 0,
714 .valid = 0,
715 .prefix = p->prefix,
716 .addr = p->addr
717 };
718
719 if (datalen + sizeof(inv) > buflen)
720 continue;
721
722 memcpy(buf + datalen, &inv, sizeof(inv));
723 datalen += sizeof(inv);
724 } else {
725 struct dhcpv6_ia_addr inv = {
726 .type = htons(DHCPV6_OPT_IA_ADDR),
727 .len = htons(sizeof(inv) - 4),
728 .addr = n->addr,
729 .preferred = 0,
730 .valid = 0
731 };
732
733 if (datalen + sizeof(inv) > buflen)
734 continue;
735
736 memcpy(buf + datalen, &inv, sizeof(inv));
737 datalen += sizeof(inv);
738 }
739 }
740 }
741 }
742 }
743
744 out.len = htons(datalen - 4);
745 memcpy(buf, &out, sizeof(out));
746 return datalen;
747 }
748
749
750 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
751 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
752 {
753 time_t now = odhcpd_time();
754 size_t response_len = 0;
755 const struct dhcpv6_client_header *hdr = data;
756 uint8_t *start = (uint8_t*)&hdr[1], *odata;
757 uint16_t otype, olen;
758
759 // Find and parse client-id and hostname
760 bool accept_reconf = false;
761 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
762 char hostname[256];
763 size_t hostname_len = 0;
764 bool class_oro = false;
765 dhcpv6_for_each_option(start, end, otype, olen, odata) {
766 if (otype == DHCPV6_OPT_CLIENTID) {
767 clid_data = odata;
768 clid_len = olen;
769
770 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
771 memcpy(mac, &odata[8], sizeof(mac));
772 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
773 memcpy(mac, &odata[4], sizeof(mac));
774 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
775 uint8_t fqdn_buf[256];
776 memcpy(fqdn_buf, odata, olen);
777 fqdn_buf[olen++] = 0;
778
779 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
780 hostname_len = strcspn(hostname, ".");
781 } else if (otype == DHCPV6_OPT_ORO) {
782 #ifdef DHCPV6_OPT_PREFIX_CLASS
783 for (size_t i = 0; i + 1 < olen; i += 2) {
784 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
785 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
786 class_oro = true;
787 }
788 #endif
789 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
790 accept_reconf = true;
791 }
792 }
793
794 if (!clid_data || !clid_len || clid_len > 130)
795 goto out;
796
797 update(iface);
798 bool update_state = false;
799
800 struct dhcpv6_assignment *first = NULL;
801 dhcpv6_for_each_option(start, end, otype, olen, odata) {
802 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
803 bool is_na = (otype == DHCPV6_OPT_IA_NA);
804 if (!is_pd && !is_na)
805 continue;
806
807 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
808 size_t ia_response_len = 0;
809 uint8_t reqlen = (is_pd) ? 62 : 128;
810 uint32_t reqhint = 0;
811
812 const uint8_t classes_max = 32;
813 uint8_t classes_cnt = 0;
814 uint16_t classes[classes_max];
815
816 // Parse request hint for IA-PD
817 if (is_pd) {
818 uint8_t *sdata;
819 uint16_t stype, slen;
820 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
821 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
822 continue;
823
824 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
825 if (p->prefix) {
826 reqlen = p->prefix;
827 reqhint = ntohl(p->addr.s6_addr32[1]);
828 if (reqlen > 32 && reqlen <= 64)
829 reqhint &= (1U << (64 - reqlen)) - 1;
830 }
831
832 #ifdef DHCPV6_OPT_PREFIX_CLASS
833 uint8_t *xdata;
834 uint16_t xtype, xlen;
835 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
836 if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
837 continue;
838
839 if (classes_cnt >= classes_max)
840 continue;
841
842 classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
843 }
844 #endif
845 }
846
847 if (reqlen > 64)
848 reqlen = 64;
849 } else if (is_na) {
850 uint8_t *sdata;
851 uint16_t stype, slen;
852 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
853 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
854 continue;
855
856 #ifdef DHCPV6_OPT_PREFIX_CLASS
857 uint8_t *xdata;
858 uint16_t xtype, xlen;
859 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
860 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
861 if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
862 continue;
863
864 if (classes_cnt >= classes_max)
865 continue;
866
867 classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
868 }
869 #endif
870 }
871 }
872
873 // Find assignment
874 struct dhcpv6_assignment *c, *a = NULL;
875 list_for_each_entry(c, &iface->ia_assignments, head) {
876 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
877 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
878 && !memcmp(c->mac, mac, sizeof(mac)))) &&
879 (c->iaid == ia->iaid || c->valid_until < now) &&
880 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
881 a = c;
882
883 // Reset state
884 apply_lease(iface, a, false);
885 memcpy(a->clid_data, clid_data, clid_len);
886 a->clid_len = clid_len;
887 a->iaid = ia->iaid;
888 a->peer = *addr;
889 a->reconf_cnt = 0;
890 a->reconf_sent = 0;
891 a->all_class = class_oro;
892 a->classes_cnt = classes_cnt;
893 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
894 if (a->classes)
895 memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
896 break;
897 }
898 }
899
900 // Generic message handling
901 uint16_t status = DHCPV6_STATUS_OK;
902 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
903 bool assigned = !!a;
904
905 if (!a && !iface->no_dynamic_dhcp) { // Create new binding
906 a = calloc(1, sizeof(*a) + clid_len);
907 if (a) {
908 a->clid_len = clid_len;
909 a->iaid = ia->iaid;
910 a->length = reqlen;
911 a->peer = *addr;
912 a->assigned = reqhint;
913 a->all_class = class_oro;
914 a->classes_cnt = classes_cnt;
915 if (classes_cnt) {
916 a->classes = malloc(classes_cnt * sizeof(uint16_t));
917 if (a->classes)
918 memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
919 }
920
921 if (first)
922 memcpy(a->key, first->key, sizeof(a->key));
923 else
924 odhcpd_urandom(a->key, sizeof(a->key));
925 memcpy(a->clid_data, clid_data, clid_len);
926
927 if (is_pd)
928 while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64);
929 else
930 assigned = assign_na(iface, a);
931 }
932 }
933
934 if (!assigned || iface->ia_addr_len == 0) { // Set error status
935 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
936 } else if (assigned && !first) { //
937 size_t handshake_len = 4;
938 buf[0] = 0;
939 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
940 buf[2] = 0;
941 buf[3] = 0;
942
943 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
944 struct dhcpv6_auth_reconfigure auth = {
945 htons(DHCPV6_OPT_AUTH),
946 htons(sizeof(auth) - 4),
947 3, 1, 0,
948 {htonl(time(NULL)), htonl(++serial)},
949 1,
950 {0}
951 };
952 memcpy(auth.key, a->key, sizeof(a->key));
953 memcpy(buf + handshake_len, &auth, sizeof(auth));
954 handshake_len += sizeof(auth);
955 }
956
957 buf += handshake_len;
958 buflen -= handshake_len;
959 response_len += handshake_len;
960
961 first = a;
962 }
963
964 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
965
966 // Was only a solicitation: mark binding for removal
967 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
968 a->valid_until = 0;
969 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
970 if (hostname_len > 0) {
971 a->hostname = realloc(a->hostname, hostname_len + 1);
972 if (a->hostname) {
973 memcpy(a->hostname, hostname, hostname_len);
974 a->hostname[hostname_len] = 0;
975 }
976 }
977 a->accept_reconf = accept_reconf;
978 apply_lease(iface, a, true);
979 update_state = true;
980 } else if (!assigned && a) { // Cleanup failed assignment
981 free(a->classes);
982 free(a->hostname);
983 free(a);
984 }
985 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
986 hdr->msg_type == DHCPV6_MSG_RELEASE ||
987 hdr->msg_type == DHCPV6_MSG_REBIND ||
988 hdr->msg_type == DHCPV6_MSG_DECLINE) {
989 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
990 status = DHCPV6_STATUS_NOBINDING;
991 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
992 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
993 hdr->msg_type == DHCPV6_MSG_REBIND) {
994 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
995 if (a)
996 apply_lease(iface, a, true);
997 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
998 a->valid_until = 0;
999 apply_lease(iface, a, false);
1000 update_state = true;
1001 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1002 a->clid_len = 0;
1003 a->valid_until = now + 3600; // Block address for 1h
1004 update_state = true;
1005 }
1006 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1007 // Always send NOTONLINK for CONFIRM so that clients restart connection
1008 status = DHCPV6_STATUS_NOTONLINK;
1009 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1010 }
1011
1012 buf += ia_response_len;
1013 buflen -= ia_response_len;
1014 response_len += ia_response_len;
1015 }
1016
1017 if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1018 buf[0] = 0;
1019 buf[1] = DHCPV6_OPT_STATUS;
1020 buf[2] = 0;
1021 buf[3] = 2;
1022 buf[4] = 0;
1023 buf[5] = DHCPV6_STATUS_OK;
1024 response_len += 6;
1025 }
1026
1027 if (update_state)
1028 dhcpv6_write_statefile();
1029
1030 out:
1031 return response_len;
1032 }
OpenWrt DHCP Server