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