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