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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 "libubox/md5.h"
19 #include "libubox/usock.h"
20
21 #include <time.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <stdio.h>
25 #include <alloca.h>
26 #include <resolv.h>
27 #include <limits.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <unistd.h>
31 #include <stdbool.h>
32 #include <arpa/inet.h>
33 #include <sys/timerfd.h>
34
35
36 static void update(struct interface *iface);
37 static void reconf_timer(struct uloop_timeout *event);
38 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
39 static uint32_t serial = 0;
40 static uint8_t statemd5[16];
41
42
43 int dhcpv6_ia_init(void)
44 {
45 uloop_timeout_set(&reconf_event, 2000);
46 return 0;
47 }
48
49
50 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
51 {
52 if (c->managed_sock.fd.registered) {
53 ustream_free(&c->managed_sock.stream);
54 close(c->managed_sock.fd.fd);
55 }
56
57 if (c->head.next)
58 list_del(&c->head);
59
60 free(c->managed);
61 free(c->hostname);
62 free(c->classes);
63 free(c);
64 }
65
66
67 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
68 {
69 if (!enable && iface->ia_assignments.next) {
70 struct dhcpv6_assignment *c;
71 while (!list_empty(&iface->ia_assignments)) {
72 c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
73 free_dhcpv6_assignment(c);
74 }
75 }
76
77 if (iface->dhcpv6 == RELAYD_SERVER) {
78 if (!iface->ia_assignments.next)
79 INIT_LIST_HEAD(&iface->ia_assignments);
80
81 if (list_empty(&iface->ia_assignments)) {
82 struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
83 if (!border) {
84 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
85 return -1;
86 }
87
88 border->length = 64;
89 list_add(&border->head, &iface->ia_assignments);
90 }
91
92 update(iface);
93
94 // Parse static entries
95 struct lease *lease;
96 list_for_each_entry(lease, &leases, head) {
97 // Construct entry
98 struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
99 if (!a) {
100 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
101 iface->ifname);
102 return -1;
103 }
104
105 a->clid_len = lease->duid_len;
106 a->length = 128;
107 if (lease->hostid) {
108 a->assigned = lease->hostid;
109 } else {
110 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
111 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
112 }
113 odhcpd_urandom(a->key, sizeof(a->key));
114 memcpy(a->clid_data, lease->duid, a->clid_len);
115 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
116
117 // Assign to all interfaces
118 struct dhcpv6_assignment *c;
119 list_for_each_entry(c, &iface->ia_assignments, head) {
120 if (c->length != 128 || c->assigned > a->assigned) {
121 list_add_tail(&a->head, &c->head);
122 break;
123 } else if (c->assigned == a->assigned) {
124 // Already an assignment with that number
125 break;
126 }
127 }
128
129 if (a->head.next) {
130 if (lease->hostname[0]) {
131 free(a->hostname);
132 a->hostname = strdup(lease->hostname);
133 }
134 } else {
135 free(a->classes);
136 free(a->hostname);
137 free(a);
138 }
139 }
140 }
141 return 0;
142 }
143
144
145 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
146 {
147 struct {
148 struct dhcpv6_client_header hdr;
149 uint16_t srvid_type;
150 uint16_t srvid_len;
151 uint16_t duid_type;
152 uint16_t hardware_type;
153 uint8_t mac[6];
154 uint16_t msg_type;
155 uint16_t msg_len;
156 uint8_t msg_id;
157 struct dhcpv6_auth_reconfigure auth;
158 uint16_t clid_type;
159 uint16_t clid_len;
160 uint8_t clid_data[128];
161 } __attribute__((packed)) reconf_msg = {
162 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
163 .srvid_type = htons(DHCPV6_OPT_SERVERID),
164 .srvid_len = htons(10),
165 .duid_type = htons(3),
166 .hardware_type = htons(1),
167 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
168 .msg_len = htons(1),
169 .msg_id = DHCPV6_MSG_RENEW,
170 .auth = {htons(DHCPV6_OPT_AUTH),
171 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
172 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
173 .clid_type = htons(DHCPV6_OPT_CLIENTID),
174 .clid_len = htons(assign->clid_len),
175 .clid_data = {0},
176 };
177
178 odhcpd_get_mac(iface, reconf_msg.mac);
179 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
180 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
181
182 md5_ctx_t md5;
183 uint8_t secretbytes[64];
184 memset(secretbytes, 0, sizeof(secretbytes));
185 memcpy(secretbytes, assign->key, sizeof(assign->key));
186
187 for (size_t i = 0; i < sizeof(secretbytes); ++i)
188 secretbytes[i] ^= 0x36;
189
190 md5_begin(&md5);
191 md5_hash(secretbytes, sizeof(secretbytes), &md5);
192 md5_hash(iov.iov_base, iov.iov_len, &md5);
193 md5_end(reconf_msg.auth.key, &md5);
194
195 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
196 secretbytes[i] ^= 0x36;
197 secretbytes[i] ^= 0x5c;
198 }
199
200 md5_begin(&md5);
201 md5_hash(secretbytes, sizeof(secretbytes), &md5);
202 md5_hash(reconf_msg.auth.key, 16, &md5);
203 md5_end(reconf_msg.auth.key, &md5);
204
205 return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
206 }
207
208
209 void dhcpv6_write_statefile(void)
210 {
211 md5_ctx_t md5;
212 md5_begin(&md5);
213
214 if (config.dhcp_statefile) {
215 time_t now = odhcpd_time(), wall_time = time(NULL);
216 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
217 if (fd < 0)
218 return;
219
220 lockf(fd, F_LOCK, 0);
221 ftruncate(fd, 0);
222
223 FILE *fp = fdopen(fd, "w");
224 if (!fp) {
225 close(fd);
226 return;
227 }
228
229 struct interface *iface;
230 list_for_each_entry(iface, &interfaces, head) {
231 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
232 continue;
233
234 if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
235 struct dhcpv6_assignment *c;
236 list_for_each_entry(c, &iface->ia_assignments, head) {
237 if (c->clid_len == 0 || c->managed_size < 0)
238 continue;
239
240 char ipbuf[INET6_ADDRSTRLEN];
241 char leasebuf[512];
242 char duidbuf[264];
243 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
244
245 // iface DUID iaid hostname lifetime assigned length [addrs...]
246 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
247 iface->ifname, duidbuf, ntohl(c->iaid),
248 (c->hostname ? c->hostname : "-"),
249 (unsigned)(c->valid_until > now ?
250 (c->valid_until - now + wall_time) : 0),
251 c->assigned, (unsigned)c->length);
252
253 struct in6_addr addr;
254 struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
255 size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
256
257 for (size_t i = 0; i < addrlen; ++i) {
258 if (addrs[i].prefix > 96)
259 continue;
260
261 addr = addrs[i].addr;
262 if (c->length == 128)
263 addr.s6_addr32[3] = htonl(c->assigned);
264 else
265 addr.s6_addr32[1] |= htonl(c->assigned);
266
267 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
268
269 if (c->length == 128 && c->hostname && i == 0) {
270 fputs(ipbuf, fp);
271
272 char b[256];
273 if (dn_expand(iface->search, iface->search + iface->search_len,
274 iface->search, b, sizeof(b)) > 0)
275 fprintf(fp, "\t%s.%s", c->hostname, b);
276
277 fprintf(fp, "\t%s\n", c->hostname);
278 md5_hash(ipbuf, strlen(ipbuf), &md5);
279 md5_hash(c->hostname, strlen(c->hostname), &md5);
280 }
281
282 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
283 (c->managed_size) ? addrs[i].prefix : c->length);
284 }
285 leasebuf[l - 1] = '\n';
286 fwrite(leasebuf, 1, l, fp);
287 }
288 }
289
290 if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
291 struct dhcpv4_assignment *c;
292 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
293 char ipbuf[INET6_ADDRSTRLEN];
294 char leasebuf[512];
295 char duidbuf[16];
296 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
297
298 // iface DUID iaid hostname lifetime assigned length [addrs...]
299 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
300 iface->ifname, duidbuf,
301 (c->hostname ? c->hostname : "-"),
302 (unsigned)(c->valid_until > now ?
303 (c->valid_until - now + wall_time) : 0),
304 c->addr);
305
306 struct in_addr addr = {htonl(c->addr)};
307 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
308
309 if (c->hostname[0]) {
310 fputs(ipbuf, fp);
311
312 char b[256];
313 if (dn_expand(iface->search, iface->search + iface->search_len,
314 iface->search, b, sizeof(b)) > 0)
315 fprintf(fp, "\t%s.%s", c->hostname, b);
316
317 fprintf(fp, "\t%s\n", c->hostname);
318 md5_hash(ipbuf, strlen(ipbuf), &md5);
319 md5_hash(c->hostname, strlen(c->hostname), &md5);
320 }
321
322 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
323 leasebuf[l - 1] = '\n';
324 fwrite(leasebuf, 1, l, fp);
325 }
326 }
327 }
328
329 fclose(fp);
330 }
331
332 uint8_t newmd5[16];
333 md5_end(newmd5, &md5);
334
335 if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
336 memcpy(statemd5, newmd5, sizeof(statemd5));
337 char *argv[2] = {config.dhcp_cb, NULL};
338 if (!vfork()) {
339 execv(argv[0], argv);
340 _exit(128);
341 }
342 }
343 }
344
345
346 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
347 {
348 if (a->length > 64 || a->managed_size < 0)
349 return;
350
351 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
352 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
353
354 for (size_t i = 0; i < addrlen; ++i) {
355 struct in6_addr prefix = addrs[i].addr;
356 prefix.s6_addr32[1] |= htonl(a->assigned);
357 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
358 iface, &a->peer.sin6_addr, add);
359 }
360 }
361
362
363 // More data was received from TCP connection
364 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
365 {
366 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
367 time_t now = odhcpd_time();
368 bool first = c->managed_size < 0;
369
370 for (;;) {
371 int pending;
372 char *data = ustream_get_read_buf(s, &pending);
373 char *end = memmem(data, pending, "\n\n", 2);
374
375 if (!end)
376 break;
377
378 end += 2;
379 end[-1] = 0;
380
381 c->managed_size = 0;
382 if (c->accept_reconf)
383 c->reconf_cnt = 1;
384
385 char *saveptr;
386 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
387 c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
388 struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
389
390 char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
391 if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
392 continue;
393
394 x = strtok_r(NULL, ",", &saveptr2);
395 if (sscanf(x, "%hhu", &n->prefix) < 1)
396 continue;
397
398 x = strtok_r(NULL, ",", &saveptr2);
399 if (sscanf(x, "%u", &n->preferred) < 1)
400 continue;
401
402 x = strtok_r(NULL, ",", &saveptr2);
403 if (sscanf(x, "%u", &n->valid) < 1)
404 continue;
405
406 if (n->preferred > n->valid)
407 continue;
408
409 if (UINT32_MAX - now < n->preferred)
410 n->preferred = UINT32_MAX;
411 else
412 n->preferred += now;
413
414 if (UINT32_MAX - now < n->valid)
415 n->valid = UINT32_MAX;
416 else
417 n->valid += now;
418
419 n->has_class = false;
420 n->class = 0;
421 n->dprefix = 0;
422
423 ++c->managed_size;
424 }
425
426 ustream_consume(s, end - data);
427 }
428
429 if (first && c->managed_size == 0)
430 free_dhcpv6_assignment(c);
431 else if (first)
432 c->valid_until = now + 150;
433 }
434
435
436 // TCP transmission has ended, either because of success or timeout or other error
437 static void managed_handle_pd_done(struct ustream *s)
438 {
439 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
440 c->valid_until = odhcpd_time() + 15;
441 c->managed_size = 0;
442 if (c->accept_reconf)
443 c->reconf_cnt = 1;
444 }
445
446
447
448 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
449 {
450 struct dhcpv6_assignment *c;
451
452 if (iface->dhcpv6_pd_manager[0]) {
453 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
454 if (fd >= 0) {
455 char iaidbuf[298];
456 odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
457
458 assign->managed_sock.stream.notify_read = managed_handle_pd_data;
459 assign->managed_sock.stream.notify_state = managed_handle_pd_done;
460 ustream_fd_init(&assign->managed_sock, fd);
461 ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
462 iaidbuf, assign->iaid, assign->length);
463 ustream_write_pending(&assign->managed_sock.stream);
464 assign->managed_size = -1;
465 assign->valid_until = odhcpd_time() + 15;
466 list_add(&assign->head, &iface->ia_assignments);
467 }
468
469 return false;
470 } else if (iface->ia_addr_len < 1) {
471 return false;
472 }
473
474 // Try honoring the hint first
475 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
476 if (assign->assigned) {
477 list_for_each_entry(c, &iface->ia_assignments, head) {
478 if (c->length == 128 || c->length == 0)
479 continue;
480
481 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
482 list_add_tail(&assign->head, &c->head);
483 apply_lease(iface, assign, true);
484 return true;
485 }
486
487 if (c->assigned != 0)
488 current = (c->assigned + (1 << (64 - c->length)));
489 }
490 }
491
492 // Fallback to a variable assignment
493 current = 1;
494 list_for_each_entry(c, &iface->ia_assignments, head) {
495 if (c->length == 128 || c->length == 0)
496 continue;
497
498 current = (current + asize) & (~asize);
499 if (current + asize < c->assigned) {
500 assign->assigned = current;
501 list_add_tail(&assign->head, &c->head);
502 apply_lease(iface, assign, true);
503 return true;
504 }
505
506 if (c->assigned != 0)
507 current = (c->assigned + (1 << (64 - c->length)));
508 }
509
510 return false;
511 }
512
513
514 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
515 {
516 bool match = false;
517 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
518 if (!iface->ia_addr[i].has_class) {
519 match = true;
520 continue;
521 } else if (assign->classes_cnt) {
522 for (size_t j = 0; j < assign->classes_cnt; ++j)
523 if (assign->classes[j] == iface->ia_addr[i].class)
524 match = true;
525 } else if (assign->all_class) {
526 match = true;
527 }
528 }
529
530 if (!match)
531 return false;
532
533 // Seed RNG with checksum of DUID
534 uint32_t seed = 0;
535 for (size_t i = 0; i < assign->clid_len; ++i)
536 seed += assign->clid_data[i];
537 srand(seed);
538
539 // Try to assign up to 100x
540 for (size_t i = 0; i < 100; ++i) {
541 uint32_t try;
542 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
543
544 struct dhcpv6_assignment *c;
545 list_for_each_entry(c, &iface->ia_assignments, head) {
546 if (c->length == 0)
547 continue;
548
549 if (c->assigned > try || c->length != 128) {
550 assign->assigned = try;
551 list_add_tail(&assign->head, &c->head);
552 return true;
553 } else if (c->assigned == try) {
554 break;
555 }
556 }
557 }
558
559 return false;
560 }
561
562
563 static int prefixcmp(const void *va, const void *vb)
564 {
565 const struct odhcpd_ipaddr *a = va, *b = vb;
566 uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
567 uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
568 return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
569 }
570
571
572 static void update(struct interface *iface)
573 {
574 struct odhcpd_ipaddr addr[8];
575 memset(addr, 0, sizeof(addr));
576 int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
577
578 if (len < 0)
579 return;
580
581 qsort(addr, len, sizeof(*addr), prefixcmp);
582
583 time_t now = odhcpd_time();
584 int minprefix = -1;
585
586 for (int i = 0; i < len; ++i) {
587 if (addr[i].prefix > minprefix)
588 minprefix = addr[i].prefix;
589
590 addr[i].addr.s6_addr32[3] = 0;
591
592 if (addr[i].preferred < UINT32_MAX - now)
593 addr[i].preferred += now;
594
595 if (addr[i].valid < UINT32_MAX - now)
596 addr[i].valid += now;
597 }
598
599 struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
600 border->assigned = 1 << (64 - minprefix);
601
602 bool change = len != (int)iface->ia_addr_len;
603 for (int i = 0; !change && i < len; ++i)
604 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
605 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
606 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
607 (addr[i].valid > (uint32_t)now + 7200) !=
608 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
609 change = true;
610
611 if (change) {
612 struct dhcpv6_assignment *c;
613 list_for_each_entry(c, &iface->ia_assignments, head)
614 if (c != border)
615 apply_lease(iface, c, false);
616 }
617
618 memcpy(iface->ia_addr, addr, len * sizeof(*addr));
619 iface->ia_addr_len = len;
620
621 if (change) { // Addresses / prefixes have changed
622 struct list_head reassign = LIST_HEAD_INIT(reassign);
623 struct dhcpv6_assignment *c, *d;
624 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
625 if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
626 continue;
627
628 if (c->length < 128 && c->assigned >= border->assigned && c != border)
629 list_move(&c->head, &reassign);
630 else if (c != border)
631 apply_lease(iface, c, true);
632
633 if (c->accept_reconf && c->reconf_cnt == 0) {
634 c->reconf_cnt = 1;
635 c->reconf_sent = now;
636 send_reconf(iface, c);
637
638 // Leave all other assignments of that client alone
639 struct dhcpv6_assignment *a;
640 list_for_each_entry(a, &iface->ia_assignments, head)
641 if (a != c && a->clid_len == c->clid_len &&
642 !memcmp(a->clid_data, c->clid_data, a->clid_len))
643 c->reconf_cnt = INT_MAX;
644 }
645 }
646
647 while (!list_empty(&reassign)) {
648 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
649 list_del(&c->head);
650 if (!assign_pd(iface, c)) {
651 c->assigned = 0;
652 list_add(&c->head, &iface->ia_assignments);
653 }
654 }
655
656 dhcpv6_write_statefile();
657 }
658 }
659
660
661 static void reconf_timer(struct uloop_timeout *event)
662 {
663 time_t now = odhcpd_time();
664 struct interface *iface;
665 list_for_each_entry(iface, &interfaces, head) {
666 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
667 continue;
668
669 struct dhcpv6_assignment *a, *n;
670 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
671 if (a->valid_until < now) {
672 if ((a->length < 128 && a->clid_len > 0) ||
673 (a->length == 128 && a->clid_len == 0)) {
674 list_del(&a->head);
675 free_dhcpv6_assignment(a);
676 }
677 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
678 now > a->reconf_sent + (1 << a->reconf_cnt)) {
679 ++a->reconf_cnt;
680 a->reconf_sent = now;
681 send_reconf(iface, a);
682 }
683 }
684 }
685 uloop_timeout_set(event, 2000);
686 }
687
688
689 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
690 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
691 struct interface *iface, bool request)
692 {
693 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
694 return 0;
695
696 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
697 size_t datalen = sizeof(out);
698 time_t now = odhcpd_time();
699
700 if (status) {
701 struct __attribute__((packed)) {
702 uint16_t type;
703 uint16_t len;
704 uint16_t value;
705 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
706 htons(status)};
707
708 memcpy(buf + datalen, &stat, sizeof(stat));
709 datalen += sizeof(stat);
710 } else {
711 if (a) {
712 uint32_t pref = 3600;
713 uint32_t valid = 3600;
714
715 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
716 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
717
718 for (size_t i = 0; i < addrlen; ++i) {
719 bool match = true;
720 if (addrs[i].has_class) {
721 match = false;
722 if (a->classes_cnt) {
723 for (size_t j = 0; j < a->classes_cnt; ++j)
724 if (a->classes[j] == addrs[i].class)
725 match = true;
726 } else if (a->all_class) {
727 match = true;
728 }
729 }
730
731 if (!match)
732 continue;
733
734 uint32_t prefix_pref = addrs[i].preferred - now;
735 uint32_t prefix_valid = addrs[i].valid - now;
736
737 if (addrs[i].prefix > 96 ||
738 addrs[i].preferred <= (uint32_t)now)
739 continue;
740
741 if (prefix_pref > 86400)
742 prefix_pref = 86400;
743
744 if (prefix_valid > 86400)
745 prefix_valid = 86400;
746
747 #ifdef DHCPV6_OPT_PREFIX_CLASS
748 struct {
749 uint16_t code;
750 uint16_t length;
751 uint16_t class;
752 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
753 htons(2), htons(iface->ia_addr[i].class)};
754 #endif
755
756 if (a->length < 128) {
757 struct dhcpv6_ia_prefix p = {
758 .type = htons(DHCPV6_OPT_IA_PREFIX),
759 .len = htons(sizeof(p) - 4),
760 .preferred = htonl(prefix_pref),
761 .valid = htonl(prefix_valid),
762 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
763 .addr = addrs[i].addr
764 };
765 p.addr.s6_addr32[1] |= htonl(a->assigned);
766
767 size_t entrlen = sizeof(p) - 4;
768
769 #ifdef DHCPV6_OPT_PREFIX_CLASS
770 if (iface->ia_addr[i].has_class) {
771 entrlen += sizeof(pclass);
772 p.len = htons(entrlen);
773 }
774 #endif
775
776 if (datalen + entrlen + 4 > buflen ||
777 (a->assigned == 0 && a->managed_size == 0))
778 continue;
779
780 memcpy(buf + datalen, &p, sizeof(p));
781 #ifdef DHCPV6_OPT_PREFIX_CLASS
782 memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
783 #endif
784 datalen += entrlen + 4;
785 } else {
786 struct dhcpv6_ia_addr n = {
787 .type = htons(DHCPV6_OPT_IA_ADDR),
788 .len = htons(sizeof(n) - 4),
789 .addr = addrs[i].addr,
790 .preferred = htonl(prefix_pref),
791 .valid = htonl(prefix_valid)
792 };
793 n.addr.s6_addr32[3] = htonl(a->assigned);
794 size_t entrlen = sizeof(n) - 4;
795
796 #ifdef DHCPV6_OPT_PREFIX_CLASS
797 if (iface->ia_addr[i].has_class) {
798 entrlen += sizeof(pclass);
799 n.len = htons(entrlen);
800 }
801 #endif
802
803 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
804 continue;
805
806 memcpy(buf + datalen, &n, sizeof(n));
807 #ifdef DHCPV6_OPT_PREFIX_CLASS
808 memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
809 #endif
810 datalen += entrlen + 4;
811 }
812
813 // Calculate T1 / T2 based on non-deprecated addresses
814 if (prefix_pref > 0) {
815 if (prefix_pref < pref)
816 pref = prefix_pref;
817
818 if (prefix_valid < valid)
819 valid = prefix_valid;
820 }
821 }
822
823 a->valid_until = valid + now;
824 out.t1 = htonl(pref * 5 / 10);
825 out.t2 = htonl(pref * 8 / 10);
826
827 if (!out.t1)
828 out.t1 = htonl(1);
829
830 if (!out.t2)
831 out.t2 = htonl(1);
832 }
833
834 if (!request) {
835 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
836 uint16_t otype, olen;
837 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
838 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
839 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
840 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
841 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
842 continue;
843
844 bool found = false;
845 if (a) {
846 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
847 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
848
849 for (size_t i = 0; i < addrlen; ++i) {
850 if (addrs[i].prefix > 96 ||
851 addrs[i].preferred <= (uint32_t)now)
852 continue;
853
854 struct in6_addr addr = addrs[i].addr;
855 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
856 addr.s6_addr32[1] |= htonl(a->assigned);
857
858 if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
859 p->prefix == a->length)
860 found = true;
861 } else {
862 addr.s6_addr32[3] = htonl(a->assigned);
863
864 if (!memcmp(&n->addr, &addr, sizeof(addr)))
865 found = true;
866 }
867 }
868 }
869
870 if (!found) {
871 if (otype == DHCPV6_OPT_IA_PREFIX) {
872 struct dhcpv6_ia_prefix inv = {
873 .type = htons(DHCPV6_OPT_IA_PREFIX),
874 .len = htons(sizeof(inv) - 4),
875 .preferred = 0,
876 .valid = 0,
877 .prefix = p->prefix,
878 .addr = p->addr
879 };
880
881 if (datalen + sizeof(inv) > buflen)
882 continue;
883
884 memcpy(buf + datalen, &inv, sizeof(inv));
885 datalen += sizeof(inv);
886 } else {
887 struct dhcpv6_ia_addr inv = {
888 .type = htons(DHCPV6_OPT_IA_ADDR),
889 .len = htons(sizeof(inv) - 4),
890 .addr = n->addr,
891 .preferred = 0,
892 .valid = 0
893 };
894
895 if (datalen + sizeof(inv) > buflen)
896 continue;
897
898 memcpy(buf + datalen, &inv, sizeof(inv));
899 datalen += sizeof(inv);
900 }
901 }
902 }
903 }
904 }
905
906 out.len = htons(datalen - 4);
907 memcpy(buf, &out, sizeof(out));
908 return datalen;
909 }
910
911
912 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
913 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
914 {
915 time_t now = odhcpd_time();
916 size_t response_len = 0;
917 const struct dhcpv6_client_header *hdr = data;
918 uint8_t *start = (uint8_t*)&hdr[1], *odata;
919 uint16_t otype, olen;
920
921 // Find and parse client-id and hostname
922 bool accept_reconf = false;
923 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
924 char hostname[256];
925 size_t hostname_len = 0;
926 bool class_oro = false;
927 dhcpv6_for_each_option(start, end, otype, olen, odata) {
928 if (otype == DHCPV6_OPT_CLIENTID) {
929 clid_data = odata;
930 clid_len = olen;
931
932 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
933 memcpy(mac, &odata[8], sizeof(mac));
934 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
935 memcpy(mac, &odata[4], sizeof(mac));
936 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
937 uint8_t fqdn_buf[256];
938 memcpy(fqdn_buf, odata, olen);
939 fqdn_buf[olen++] = 0;
940
941 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
942 hostname_len = strcspn(hostname, ".");
943 } else if (otype == DHCPV6_OPT_ORO) {
944 #ifdef DHCPV6_OPT_PREFIX_CLASS
945 for (size_t i = 0; i + 1 < olen; i += 2) {
946 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
947 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
948 class_oro = true;
949 }
950 #endif
951 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
952 accept_reconf = true;
953 }
954 }
955
956 if (!clid_data || !clid_len || clid_len > 130)
957 goto out;
958
959 update(iface);
960 bool update_state = false;
961
962 struct dhcpv6_assignment *first = NULL;
963 dhcpv6_for_each_option(start, end, otype, olen, odata) {
964 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
965 bool is_na = (otype == DHCPV6_OPT_IA_NA);
966 if (!is_pd && !is_na)
967 continue;
968
969 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
970 size_t ia_response_len = 0;
971 uint8_t reqlen = (is_pd) ? 62 : 128;
972 uint32_t reqhint = 0;
973
974 const uint8_t classes_max = 32;
975 uint8_t classes_cnt = 0;
976 uint16_t classes[classes_max];
977
978 // Parse request hint for IA-PD
979 if (is_pd) {
980 uint8_t *sdata;
981 uint16_t stype, slen;
982 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
983 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
984 continue;
985
986 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
987 if (p->prefix) {
988 reqlen = p->prefix;
989 reqhint = ntohl(p->addr.s6_addr32[1]);
990 if (reqlen > 32 && reqlen <= 64)
991 reqhint &= (1U << (64 - reqlen)) - 1;
992 }
993
994 #ifdef DHCPV6_OPT_PREFIX_CLASS
995 uint8_t *xdata;
996 uint16_t xtype, xlen;
997 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
998 if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
999 continue;
1000
1001 if (classes_cnt >= classes_max)
1002 continue;
1003
1004 classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1005 }
1006 #endif
1007 }
1008
1009 if (reqlen > 64)
1010 reqlen = 64;
1011 } else if (is_na) {
1012 uint8_t *sdata;
1013 uint16_t stype, slen;
1014 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1015 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1016 continue;
1017
1018 #ifdef DHCPV6_OPT_PREFIX_CLASS
1019 uint8_t *xdata;
1020 uint16_t xtype, xlen;
1021 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
1022 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
1023 if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
1024 continue;
1025
1026 if (classes_cnt >= classes_max)
1027 continue;
1028
1029 classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1030 }
1031 #endif
1032 }
1033 }
1034
1035 // Find assignment
1036 struct dhcpv6_assignment *c, *a = NULL;
1037 list_for_each_entry(c, &iface->ia_assignments, head) {
1038 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1039 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1040 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1041 (c->iaid == ia->iaid || c->valid_until < now) &&
1042 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1043 a = c;
1044
1045 // Reset state
1046 apply_lease(iface, a, false);
1047 memcpy(a->clid_data, clid_data, clid_len);
1048 a->clid_len = clid_len;
1049 a->iaid = ia->iaid;
1050 a->peer = *addr;
1051 a->reconf_cnt = 0;
1052 a->reconf_sent = 0;
1053 a->all_class = class_oro;
1054 a->classes_cnt = classes_cnt;
1055 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
1056 if (a->classes)
1057 memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1058 break;
1059 }
1060 }
1061
1062 // Generic message handling
1063 uint16_t status = DHCPV6_STATUS_OK;
1064 if (a && a->managed_size < 0) {
1065 return -1;
1066 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1067 bool assigned = !!a;
1068
1069 if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1070 a = calloc(1, sizeof(*a) + clid_len);
1071 if (a) {
1072 a->clid_len = clid_len;
1073 a->iaid = ia->iaid;
1074 a->length = reqlen;
1075 a->peer = *addr;
1076 a->assigned = reqhint;
1077 a->all_class = class_oro;
1078 a->classes_cnt = classes_cnt;
1079 if (classes_cnt) {
1080 a->classes = malloc(classes_cnt * sizeof(uint16_t));
1081 if (a->classes)
1082 memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1083 }
1084
1085 if (first)
1086 memcpy(a->key, first->key, sizeof(a->key));
1087 else
1088 odhcpd_urandom(a->key, sizeof(a->key));
1089 memcpy(a->clid_data, clid_data, clid_len);
1090
1091 if (is_pd)
1092 while (!(assigned = assign_pd(iface, a)) &&
1093 !a->managed_size && ++a->length <= 64);
1094 else
1095 assigned = assign_na(iface, a);
1096
1097 if (a->managed_size && !assigned)
1098 return -1;
1099 }
1100 }
1101
1102 if (!assigned || iface->ia_addr_len == 0) { // Set error status
1103 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1104 } else if (assigned && !first) { //
1105 size_t handshake_len = 4;
1106 buf[0] = 0;
1107 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1108 buf[2] = 0;
1109 buf[3] = 0;
1110
1111 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1112 struct dhcpv6_auth_reconfigure auth = {
1113 htons(DHCPV6_OPT_AUTH),
1114 htons(sizeof(auth) - 4),
1115 3, 1, 0,
1116 {htonl(time(NULL)), htonl(++serial)},
1117 1,
1118 {0}
1119 };
1120 memcpy(auth.key, a->key, sizeof(a->key));
1121 memcpy(buf + handshake_len, &auth, sizeof(auth));
1122 handshake_len += sizeof(auth);
1123 }
1124
1125 buf += handshake_len;
1126 buflen -= handshake_len;
1127 response_len += handshake_len;
1128
1129 first = a;
1130 }
1131
1132 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1133
1134 // Was only a solicitation: mark binding for removal
1135 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1136 a->valid_until = 0;
1137 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1138 if (hostname_len > 0) {
1139 a->hostname = realloc(a->hostname, hostname_len + 1);
1140 if (a->hostname) {
1141 memcpy(a->hostname, hostname, hostname_len);
1142 a->hostname[hostname_len] = 0;
1143 }
1144 }
1145 a->accept_reconf = accept_reconf;
1146 apply_lease(iface, a, true);
1147 update_state = true;
1148 } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1149 free_dhcpv6_assignment(a);
1150 }
1151 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1152 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1153 hdr->msg_type == DHCPV6_MSG_REBIND ||
1154 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1155 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1156 status = DHCPV6_STATUS_NOBINDING;
1157 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1158 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1159 hdr->msg_type == DHCPV6_MSG_REBIND) {
1160 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1161 if (a)
1162 apply_lease(iface, a, true);
1163 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1164 a->valid_until = 0;
1165 apply_lease(iface, a, false);
1166 update_state = true;
1167 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1168 a->clid_len = 0;
1169 a->valid_until = now + 3600; // Block address for 1h
1170 update_state = true;
1171 }
1172 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1173 // Always send NOTONLINK for CONFIRM so that clients restart connection
1174 status = DHCPV6_STATUS_NOTONLINK;
1175 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1176 }
1177
1178 buf += ia_response_len;
1179 buflen -= ia_response_len;
1180 response_len += ia_response_len;
1181 }
1182
1183 if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1184 buf[0] = 0;
1185 buf[1] = DHCPV6_OPT_STATUS;
1186 buf[2] = 0;
1187 buf[3] = 2;
1188 buf[4] = 0;
1189 buf[5] = DHCPV6_STATUS_OK;
1190 response_len += 6;
1191 }
1192
1193 if (update_state)
1194 dhcpv6_write_statefile();
1195
1196 out:
1197 return response_len;
1198 }
OpenWrt DHCP Server