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dhcpv6: fix mac-handling
[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 <poll.h>
26 #include <alloca.h>
27 #include <resolv.h>
28 #include <limits.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 #include <stdbool.h>
33 #include <arpa/inet.h>
34 #include <sys/timerfd.h>
35
36
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);
63 }
64
65
66 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
67 {
68 if (!enable && iface->ia_assignments.next) {
69 struct dhcpv6_assignment *c;
70 while (!list_empty(&iface->ia_assignments)) {
71 c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
72 free_dhcpv6_assignment(c);
73 }
74 }
75
76 if (enable && iface->dhcpv6 == RELAYD_SERVER) {
77 if (!iface->ia_assignments.next)
78 INIT_LIST_HEAD(&iface->ia_assignments);
79
80 if (list_empty(&iface->ia_assignments)) {
81 struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
82 if (!border) {
83 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
84 return -1;
85 }
86
87 border->length = 64;
88 list_add(&border->head, &iface->ia_assignments);
89 }
90
91 // Parse static entries
92 struct lease *lease;
93 list_for_each_entry(lease, &leases, head) {
94 // Construct entry
95 size_t duid_len = lease->duid_len ? lease->duid_len : 14;
96 struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
97 if (!a) {
98 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
99 iface->ifname);
100 return -1;
101 }
102
103 a->clid_len = duid_len;
104 a->length = 128;
105 if (lease->hostid) {
106 a->assigned = lease->hostid;
107 } else {
108 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
109 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
110 }
111 odhcpd_urandom(a->key, sizeof(a->key));
112 memcpy(a->clid_data, lease->duid, a->clid_len);
113 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
114
115 // Assign to all interfaces
116 struct dhcpv6_assignment *c;
117 list_for_each_entry(c, &iface->ia_assignments, head) {
118 if (c->length != 128 || c->assigned > a->assigned) {
119 list_add_tail(&a->head, &c->head);
120 break;
121 } else if (c->assigned == a->assigned) {
122 // Already an assignment with that number
123 break;
124 }
125 }
126
127 if (a->head.next) {
128 if (lease->hostname[0]) {
129 free(a->hostname);
130 a->hostname = strdup(lease->hostname);
131 }
132 } else {
133 free(a->hostname);
134 free(a);
135 }
136 }
137 }
138 return 0;
139 }
140
141
142 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
143 {
144 struct {
145 struct dhcpv6_client_header hdr;
146 uint16_t srvid_type;
147 uint16_t srvid_len;
148 uint16_t duid_type;
149 uint16_t hardware_type;
150 uint8_t mac[6];
151 uint16_t msg_type;
152 uint16_t msg_len;
153 uint8_t msg_id;
154 struct dhcpv6_auth_reconfigure auth;
155 uint16_t clid_type;
156 uint16_t clid_len;
157 uint8_t clid_data[128];
158 } __attribute__((packed)) reconf_msg = {
159 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
160 .srvid_type = htons(DHCPV6_OPT_SERVERID),
161 .srvid_len = htons(10),
162 .duid_type = htons(3),
163 .hardware_type = htons(1),
164 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
165 .msg_len = htons(1),
166 .msg_id = DHCPV6_MSG_RENEW,
167 .auth = {htons(DHCPV6_OPT_AUTH),
168 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
169 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
170 .clid_type = htons(DHCPV6_OPT_CLIENTID),
171 .clid_len = htons(assign->clid_len),
172 .clid_data = {0},
173 };
174
175 odhcpd_get_mac(iface, reconf_msg.mac);
176 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
177 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
178
179 md5_ctx_t md5;
180 uint8_t secretbytes[64];
181 memset(secretbytes, 0, sizeof(secretbytes));
182 memcpy(secretbytes, assign->key, sizeof(assign->key));
183
184 for (size_t i = 0; i < sizeof(secretbytes); ++i)
185 secretbytes[i] ^= 0x36;
186
187 md5_begin(&md5);
188 md5_hash(secretbytes, sizeof(secretbytes), &md5);
189 md5_hash(iov.iov_base, iov.iov_len, &md5);
190 md5_end(reconf_msg.auth.key, &md5);
191
192 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
193 secretbytes[i] ^= 0x36;
194 secretbytes[i] ^= 0x5c;
195 }
196
197 md5_begin(&md5);
198 md5_hash(secretbytes, sizeof(secretbytes), &md5);
199 md5_hash(reconf_msg.auth.key, 16, &md5);
200 md5_end(reconf_msg.auth.key, &md5);
201
202 return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
203 }
204
205
206 void dhcpv6_write_statefile(void)
207 {
208 md5_ctx_t md5;
209 md5_begin(&md5);
210
211 if (config.dhcp_statefile) {
212 time_t now = odhcpd_time(), wall_time = time(NULL);
213 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
214 if (fd < 0)
215 return;
216
217 lockf(fd, F_LOCK, 0);
218 if (ftruncate(fd, 0) < 0) {}
219
220 FILE *fp = fdopen(fd, "w");
221 if (!fp) {
222 close(fd);
223 return;
224 }
225
226 struct interface *iface;
227 list_for_each_entry(iface, &interfaces, head) {
228 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
229 continue;
230
231 if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
232 struct dhcpv6_assignment *c;
233 list_for_each_entry(c, &iface->ia_assignments, head) {
234 if (c->clid_len == 0 || c->managed_size < 0)
235 continue;
236
237 char ipbuf[INET6_ADDRSTRLEN];
238 char leasebuf[512];
239 char duidbuf[264];
240 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
241
242 // iface DUID iaid hostname lifetime assigned length [addrs...]
243 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
244 iface->ifname, duidbuf, ntohl(c->iaid),
245 (c->hostname ? c->hostname : "-"),
246 (unsigned)(c->valid_until > now ?
247 (c->valid_until - now + wall_time) : 0),
248 c->assigned, (unsigned)c->length);
249
250 struct in6_addr addr;
251 struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
252 size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
253 size_t m = 0;
254
255 for (size_t i = 0; i < addrlen; ++i)
256 if (addrs[i].preferred > addrs[m].preferred ||
257 (addrs[i].preferred == addrs[m].preferred &&
258 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
259 m = i;
260
261 for (size_t i = 0; i < addrlen; ++i) {
262 if (addrs[i].prefix > 96 || c->valid_until <= now ||
263 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
264 addrs[i].prefix == 64))
265 continue;
266
267 addr = addrs[i].addr;
268 if (c->length == 128)
269 addr.s6_addr32[3] = htonl(c->assigned);
270 else
271 addr.s6_addr32[1] |= htonl(c->assigned);
272
273 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
274
275 if (c->length == 128 && c->hostname) {
276 fputs(ipbuf, fp);
277
278 char b[256];
279 if (dn_expand(iface->search, iface->search + iface->search_len,
280 iface->search, b, sizeof(b)) > 0)
281 fprintf(fp, "\t%s.%s", c->hostname, b);
282
283 fprintf(fp, "\t%s\n", c->hostname);
284 md5_hash(ipbuf, strlen(ipbuf), &md5);
285 md5_hash(c->hostname, strlen(c->hostname), &md5);
286 }
287
288 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
289 (c->managed_size) ? addrs[i].prefix : c->length);
290 }
291 leasebuf[l - 1] = '\n';
292 fwrite(leasebuf, 1, l, fp);
293 }
294 }
295
296 if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
297 struct dhcpv4_assignment *c;
298 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
299 char ipbuf[INET6_ADDRSTRLEN];
300 char leasebuf[512];
301 char duidbuf[16];
302 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
303
304 // iface DUID iaid hostname lifetime assigned length [addrs...]
305 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
306 iface->ifname, duidbuf,
307 (c->hostname ? c->hostname : "-"),
308 (unsigned)(c->valid_until > now ?
309 (c->valid_until - now + wall_time) : 0),
310 c->addr);
311
312 struct in_addr addr = {htonl(c->addr)};
313 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
314
315 if (c->hostname[0]) {
316 fputs(ipbuf, fp);
317
318 char b[256];
319 if (dn_expand(iface->search, iface->search + iface->search_len,
320 iface->search, b, sizeof(b)) > 0)
321 fprintf(fp, "\t%s.%s", c->hostname, b);
322
323 fprintf(fp, "\t%s\n", c->hostname);
324 md5_hash(ipbuf, strlen(ipbuf), &md5);
325 md5_hash(c->hostname, strlen(c->hostname), &md5);
326 }
327
328 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
329 leasebuf[l - 1] = '\n';
330 fwrite(leasebuf, 1, l, fp);
331 }
332 }
333 }
334
335 fclose(fp);
336 }
337
338 uint8_t newmd5[16];
339 md5_end(newmd5, &md5);
340
341 if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
342 memcpy(statemd5, newmd5, sizeof(statemd5));
343 char *argv[2] = {config.dhcp_cb, NULL};
344 if (!vfork()) {
345 execv(argv[0], argv);
346 _exit(128);
347 }
348 }
349 }
350
351
352 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
353 {
354 if (a->length > 64 || a->managed_size < 0)
355 return;
356
357 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
358 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
359
360 for (size_t i = 0; i < addrlen; ++i) {
361 struct in6_addr prefix = addrs[i].addr;
362 prefix.s6_addr32[1] |= htonl(a->assigned);
363 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
364 iface, &a->peer.sin6_addr, 1024, add);
365 }
366 }
367
368
369 // More data was received from TCP connection
370 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
371 {
372 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
373 time_t now = odhcpd_time();
374 bool first = c->managed_size < 0;
375
376 for (;;) {
377 int pending;
378 char *data = ustream_get_read_buf(s, &pending);
379 char *end = memmem(data, pending, "\n\n", 2);
380
381 if (!end)
382 break;
383
384 end += 2;
385 end[-1] = 0;
386
387 c->managed_size = 0;
388 if (c->accept_reconf)
389 c->reconf_cnt = 1;
390
391 char *saveptr;
392 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
393 c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
394 struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
395
396 char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
397 if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
398 continue;
399
400 x = strtok_r(NULL, ",", &saveptr2);
401 if (sscanf(x, "%hhu", &n->prefix) < 1)
402 continue;
403
404 x = strtok_r(NULL, ",", &saveptr2);
405 if (sscanf(x, "%u", &n->preferred) < 1)
406 continue;
407
408 x = strtok_r(NULL, ",", &saveptr2);
409 if (sscanf(x, "%u", &n->valid) < 1)
410 continue;
411
412 if (n->preferred > n->valid)
413 continue;
414
415 if (UINT32_MAX - now < n->preferred)
416 n->preferred = UINT32_MAX;
417 else
418 n->preferred += now;
419
420 if (UINT32_MAX - now < n->valid)
421 n->valid = UINT32_MAX;
422 else
423 n->valid += now;
424
425 n->dprefix = 0;
426
427 ++c->managed_size;
428 }
429
430 ustream_consume(s, end - data);
431 }
432
433 if (first && c->managed_size == 0)
434 free_dhcpv6_assignment(c);
435 else if (first)
436 c->valid_until = now + 150;
437 }
438
439
440 // TCP transmission has ended, either because of success or timeout or other error
441 static void managed_handle_pd_done(struct ustream *s)
442 {
443 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
444 c->valid_until = odhcpd_time() + 15;
445 c->managed_size = 0;
446 if (c->accept_reconf)
447 c->reconf_cnt = 1;
448 }
449
450
451
452 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
453 {
454 struct dhcpv6_assignment *c;
455
456 if (iface->dhcpv6_pd_manager[0]) {
457 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
458 if (fd >= 0) {
459 char iaidbuf[298];
460 odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
461
462 assign->managed_sock.stream.notify_read = managed_handle_pd_data;
463 assign->managed_sock.stream.notify_state = managed_handle_pd_done;
464 ustream_fd_init(&assign->managed_sock, fd);
465 ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
466 iaidbuf, assign->iaid, assign->length);
467 ustream_write_pending(&assign->managed_sock.stream);
468 assign->managed_size = -1;
469 assign->valid_until = odhcpd_time() + 15;
470 list_add(&assign->head, &iface->ia_assignments);
471
472 // Wait initial period of up to 250ms for immediate assignment
473 struct pollfd pfd = { .fd = fd, .events = POLLIN };
474 poll(&pfd, 1, 250);
475 managed_handle_pd_data(&assign->managed_sock.stream, 0);
476
477 if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
478 return true;
479 }
480
481 return false;
482 } else if (iface->ia_addr_len < 1) {
483 return false;
484 }
485
486 // Try honoring the hint first
487 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
488 if (assign->assigned) {
489 list_for_each_entry(c, &iface->ia_assignments, head) {
490 if (c->length == 128 || c->length == 0)
491 continue;
492
493 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
494 list_add_tail(&assign->head, &c->head);
495 apply_lease(iface, assign, true);
496 return true;
497 }
498
499 if (c->assigned != 0)
500 current = (c->assigned + (1 << (64 - c->length)));
501 }
502 }
503
504 // Fallback to a variable assignment
505 current = 1;
506 list_for_each_entry(c, &iface->ia_assignments, head) {
507 if (c->length == 128 || c->length == 0)
508 continue;
509
510 current = (current + asize) & (~asize);
511 if (current + asize < c->assigned) {
512 assign->assigned = current;
513 list_add_tail(&assign->head, &c->head);
514 apply_lease(iface, assign, true);
515 return true;
516 }
517
518 if (c->assigned != 0)
519 current = (c->assigned + (1 << (64 - c->length)));
520 }
521
522 return false;
523 }
524
525
526 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
527 {
528 // Seed RNG with checksum of DUID
529 uint32_t seed = 0;
530 for (size_t i = 0; i < assign->clid_len; ++i)
531 seed += assign->clid_data[i];
532 srand(seed);
533
534 // Try to assign up to 100x
535 for (size_t i = 0; i < 100; ++i) {
536 uint32_t try;
537 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
538
539 struct dhcpv6_assignment *c;
540 list_for_each_entry(c, &iface->ia_assignments, head) {
541 if (c->length == 0)
542 continue;
543
544 if (c->assigned > try || c->length != 128) {
545 assign->assigned = try;
546 list_add_tail(&assign->head, &c->head);
547 return true;
548 } else if (c->assigned == try) {
549 break;
550 }
551 }
552 }
553
554 return false;
555 }
556
557 void dhcpv6_ia_preupdate(struct interface *iface)
558 {
559 if (iface->dhcpv6 != RELAYD_SERVER)
560 return;
561
562 struct dhcpv6_assignment *c, *border = list_last_entry(
563 &iface->ia_assignments, struct dhcpv6_assignment, head);
564 list_for_each_entry(c, &iface->ia_assignments, head)
565 if (c != border && !iface->managed)
566 apply_lease(iface, c, false);
567 }
568
569 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
570 {
571 if (iface->dhcpv6 != RELAYD_SERVER)
572 return;
573
574 int minprefix = -1;
575 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
576 if (iface->ia_addr[i].preferred > (uint32_t)now &&
577 iface->ia_addr[i].prefix < 64 &&
578 iface->ia_addr[i].prefix > minprefix)
579 minprefix = iface->ia_addr[i].prefix;
580 }
581
582 struct dhcpv6_assignment *border = list_last_entry(
583 &iface->ia_assignments, struct dhcpv6_assignment, head);
584 if (minprefix > 32 && minprefix <= 64)
585 border->assigned = 1U << (64 - minprefix);
586 else
587 border->assigned = 0;
588
589 struct list_head reassign = LIST_HEAD_INIT(reassign);
590 struct dhcpv6_assignment *c, *d;
591 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
592 if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
593 continue;
594
595 if (c->length < 128 && c->assigned >= border->assigned && c != border)
596 list_move(&c->head, &reassign);
597 else if (c != border)
598 apply_lease(iface, c, true);
599
600 if (c->accept_reconf && c->reconf_cnt == 0) {
601 c->reconf_cnt = 1;
602 c->reconf_sent = now;
603 send_reconf(iface, c);
604
605 // Leave all other assignments of that client alone
606 struct dhcpv6_assignment *a;
607 list_for_each_entry(a, &iface->ia_assignments, head)
608 if (a != c && a->clid_len == c->clid_len &&
609 !memcmp(a->clid_data, c->clid_data, a->clid_len))
610 c->reconf_cnt = INT_MAX;
611 }
612 }
613
614 while (!list_empty(&reassign)) {
615 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
616 list_del(&c->head);
617 if (!assign_pd(iface, c)) {
618 c->assigned = 0;
619 list_add(&c->head, &iface->ia_assignments);
620 }
621 }
622
623 dhcpv6_write_statefile();
624 }
625
626
627 static void reconf_timer(struct uloop_timeout *event)
628 {
629 time_t now = odhcpd_time();
630 struct interface *iface;
631 list_for_each_entry(iface, &interfaces, head) {
632 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
633 continue;
634
635 struct dhcpv6_assignment *a, *n;
636 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
637 if (a->valid_until < now) {
638 if ((a->length < 128 && a->clid_len > 0) ||
639 (a->length == 128 && a->clid_len == 0)) {
640 list_del(&a->head);
641 free_dhcpv6_assignment(a);
642 }
643 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
644 now > a->reconf_sent + (1 << a->reconf_cnt)) {
645 ++a->reconf_cnt;
646 a->reconf_sent = now;
647 send_reconf(iface, a);
648 }
649 }
650 }
651 uloop_timeout_set(event, 2000);
652 }
653
654
655 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
656 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
657 struct interface *iface, bool request)
658 {
659 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
660 return 0;
661
662 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
663 size_t datalen = sizeof(out);
664 time_t now = odhcpd_time();
665
666 if (status) {
667 struct __attribute__((packed)) {
668 uint16_t type;
669 uint16_t len;
670 uint16_t value;
671 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
672 htons(status)};
673
674 memcpy(buf + datalen, &stat, sizeof(stat));
675 datalen += sizeof(stat);
676 } else {
677 if (a) {
678 uint32_t leasetime = iface->dhcpv4_leasetime;
679 if (leasetime == 0)
680 leasetime = 3600;
681 else if (leasetime < 60)
682 leasetime = 60;
683
684 uint32_t pref = leasetime;
685 uint32_t valid = leasetime;
686
687 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
688 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
689 size_t m = 0;
690
691 for (size_t i = 0; i < addrlen; ++i)
692 if (addrs[i].preferred > addrs[m].preferred ||
693 (addrs[i].preferred == addrs[m].preferred &&
694 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
695 m = i;
696
697 for (size_t i = 0; i < addrlen; ++i) {
698 uint32_t prefix_pref = addrs[i].preferred;
699 uint32_t prefix_valid = addrs[i].valid;
700
701 if (addrs[i].prefix > 96 ||
702 addrs[i].preferred <= (uint32_t)now)
703 continue;
704
705 if (prefix_pref != UINT32_MAX)
706 prefix_pref -= now;
707
708 if (prefix_valid != UINT32_MAX)
709 prefix_valid -= now;
710
711 if (a->length < 128) {
712 struct dhcpv6_ia_prefix p = {
713 .type = htons(DHCPV6_OPT_IA_PREFIX),
714 .len = htons(sizeof(p) - 4),
715 .preferred = htonl(prefix_pref),
716 .valid = htonl(prefix_valid),
717 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
718 .addr = addrs[i].addr
719 };
720 p.addr.s6_addr32[1] |= htonl(a->assigned);
721
722 size_t entrlen = sizeof(p) - 4;
723
724 if (datalen + entrlen + 4 > buflen ||
725 (a->assigned == 0 && a->managed_size == 0) ||
726 (!a->managed_size && a->length <= addrs[i].prefix))
727 continue;
728
729 memcpy(buf + datalen, &p, sizeof(p));
730 datalen += entrlen + 4;
731 } else {
732 struct dhcpv6_ia_addr n = {
733 .type = htons(DHCPV6_OPT_IA_ADDR),
734 .len = htons(sizeof(n) - 4),
735 .addr = addrs[i].addr,
736 .preferred = htonl(prefix_pref),
737 .valid = htonl(prefix_valid)
738 };
739 n.addr.s6_addr32[3] = htonl(a->assigned);
740 size_t entrlen = sizeof(n) - 4;
741
742 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
743 addrs[i].prefix <= 64)
744 continue;
745
746 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
747 continue;
748
749 memcpy(buf + datalen, &n, sizeof(n));
750 datalen += entrlen + 4;
751 }
752
753 // Calculate T1 / T2 based on non-deprecated addresses
754 if (prefix_pref > 0) {
755 if (prefix_pref < pref)
756 pref = prefix_pref;
757
758 if (prefix_valid < valid)
759 valid = prefix_valid;
760 }
761 }
762
763 a->valid_until = valid + now;
764 out.t1 = htonl(pref * 5 / 10);
765 out.t2 = htonl(pref * 8 / 10);
766
767 if (!out.t1)
768 out.t1 = htonl(1);
769
770 if (!out.t2)
771 out.t2 = htonl(1);
772 }
773
774 if (!request) {
775 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
776 uint16_t otype, olen;
777 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
778 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
779 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
780 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
781 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
782 continue;
783
784 bool found = false;
785 if (a) {
786 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
787 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
788
789 for (size_t i = 0; i < addrlen; ++i) {
790 if (addrs[i].prefix > 96 ||
791 addrs[i].preferred <= (uint32_t)now)
792 continue;
793
794 struct in6_addr addr = addrs[i].addr;
795 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
796 addr.s6_addr32[1] |= htonl(a->assigned);
797
798 if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
799 p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
800 found = true;
801 } else {
802 addr.s6_addr32[3] = htonl(a->assigned);
803
804 if (!memcmp(&n->addr, &addr, sizeof(addr)))
805 found = true;
806 }
807 }
808 }
809
810 if (!found) {
811 if (otype == DHCPV6_OPT_IA_PREFIX) {
812 struct dhcpv6_ia_prefix inv = {
813 .type = htons(DHCPV6_OPT_IA_PREFIX),
814 .len = htons(sizeof(inv) - 4),
815 .preferred = 0,
816 .valid = 0,
817 .prefix = p->prefix,
818 .addr = p->addr
819 };
820
821 if (datalen + sizeof(inv) > buflen)
822 continue;
823
824 memcpy(buf + datalen, &inv, sizeof(inv));
825 datalen += sizeof(inv);
826 } else {
827 struct dhcpv6_ia_addr inv = {
828 .type = htons(DHCPV6_OPT_IA_ADDR),
829 .len = htons(sizeof(inv) - 4),
830 .addr = n->addr,
831 .preferred = 0,
832 .valid = 0
833 };
834
835 if (datalen + sizeof(inv) > buflen)
836 continue;
837
838 memcpy(buf + datalen, &inv, sizeof(inv));
839 datalen += sizeof(inv);
840 }
841 }
842 }
843 }
844 }
845
846 out.len = htons(datalen - 4);
847 memcpy(buf, &out, sizeof(out));
848 return datalen;
849 }
850
851
852 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
853 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
854 {
855 const char *type = "UNKNOWN";
856 const char *status = "UNKNOWN";
857
858 if (msgtype == DHCPV6_MSG_RENEW)
859 return;
860
861 switch (msgtype) {
862 case DHCPV6_MSG_SOLICIT:
863 type = "SOLICIT";
864 break;
865 case DHCPV6_MSG_REQUEST:
866 type = "REQUEST";
867 break;
868 case DHCPV6_MSG_CONFIRM:
869 type = "CONFIRM";
870 break;
871 case DHCPV6_MSG_RENEW:
872 type = "RENEW";
873 break;
874 case DHCPV6_MSG_REBIND:
875 type = "REBIND";
876 break;
877 case DHCPV6_MSG_RELEASE:
878 type = "RELEASE";
879 break;
880 case DHCPV6_MSG_DECLINE:
881 type = "DECLINE";
882 break;
883 }
884
885 switch (code) {
886 case DHCPV6_STATUS_OK:
887 status = "ok";
888 break;
889 case DHCPV6_STATUS_NOADDRSAVAIL:
890 status = "no addresses available";
891 break;
892 case DHCPV6_STATUS_NOBINDING:
893 status = "no binding";
894 break;
895 case DHCPV6_STATUS_NOTONLINK:
896 status = "not on-link";
897 break;
898 case DHCPV6_STATUS_NOPREFIXAVAIL:
899 status = "no prefix available";
900 break;
901 }
902
903 char leasebuf[256] = "";
904
905 if (a) {
906 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
907 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
908 size_t lbsize = 0;
909 char addrbuf[INET6_ADDRSTRLEN];
910
911 for (size_t i = 0; i < addrlen; ++i) {
912 if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
913 continue;
914
915 struct in6_addr addr = addrs[i].addr;
916 int prefix = a->managed ? addrs[i].prefix : a->length;
917 if (prefix == 128)
918 addr.s6_addr32[3] = htonl(a->assigned);
919 else
920 addr.s6_addr32[1] |= htonl(a->assigned);
921
922 inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
923 lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
924 }
925 }
926
927 syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
928 duidbuf, iface->ifname, status, leasebuf);
929 }
930
931
932
933 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
934 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
935 {
936 time_t now = odhcpd_time();
937 size_t response_len = 0;
938 const struct dhcpv6_client_header *hdr = data;
939 uint8_t *start = (uint8_t*)&hdr[1], *odata;
940 uint16_t otype, olen;
941
942 // Find and parse client-id and hostname
943 bool accept_reconf = false;
944 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
945 char hostname[256];
946 size_t hostname_len = 0;
947 bool notonlink = false;
948 char duidbuf[261];
949
950 dhcpv6_for_each_option(start, end, otype, olen, odata) {
951 if (otype == DHCPV6_OPT_CLIENTID) {
952 clid_data = odata;
953 clid_len = olen;
954
955 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
956 memcpy(mac, &odata[8], sizeof(mac));
957 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
958 memcpy(mac, &odata[4], sizeof(mac));
959
960 if (olen <= 130)
961 odhcpd_hexlify(duidbuf, odata, olen);
962 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
963 uint8_t fqdn_buf[256];
964 memcpy(fqdn_buf, odata, olen);
965 fqdn_buf[olen++] = 0;
966
967 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
968 hostname_len = strcspn(hostname, ".");
969 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
970 accept_reconf = true;
971 }
972 }
973
974 if (!clid_data || !clid_len || clid_len > 130)
975 goto out;
976
977 struct dhcpv6_assignment *first = NULL;
978 dhcpv6_for_each_option(start, end, otype, olen, odata) {
979 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
980 bool is_na = (otype == DHCPV6_OPT_IA_NA);
981 bool ia_addr_present = false;
982 if (!is_pd && !is_na)
983 continue;
984
985 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
986 size_t ia_response_len = 0;
987 uint8_t reqlen = (is_pd) ? 62 : 128;
988 uint32_t reqhint = 0;
989
990 // Parse request hint for IA-PD
991 if (is_pd) {
992 uint8_t *sdata;
993 uint16_t stype, slen;
994 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
995 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
996 continue;
997
998 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
999 if (p->prefix) {
1000 reqlen = p->prefix;
1001 reqhint = ntohl(p->addr.s6_addr32[1]);
1002 if (reqlen > 32 && reqlen <= 64)
1003 reqhint &= (1U << (64 - reqlen)) - 1;
1004 }
1005 }
1006
1007 if (reqlen > 64)
1008 reqlen = 64;
1009 } else if (is_na) {
1010 uint8_t *sdata;
1011 uint16_t stype, slen;
1012 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1013 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1014 continue;
1015
1016 ia_addr_present = true;
1017 }
1018 }
1019
1020 // Find assignment
1021 struct dhcpv6_assignment *c, *a = NULL;
1022 list_for_each_entry(c, &iface->ia_assignments, head) {
1023 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1024 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1025 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1026 (c->iaid == ia->iaid || c->valid_until < now) &&
1027 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1028 a = c;
1029
1030 // Reset state
1031 apply_lease(iface, a, false);
1032 memcpy(a->clid_data, clid_data, clid_len);
1033 a->clid_len = clid_len;
1034 a->iaid = ia->iaid;
1035 a->peer = *addr;
1036 a->reconf_cnt = 0;
1037 a->reconf_sent = 0;
1038 break;
1039 }
1040 }
1041
1042 // Generic message handling
1043 uint16_t status = DHCPV6_STATUS_OK;
1044 if (a && a->managed_size < 0) {
1045 return -1;
1046 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1047 bool assigned = !!a;
1048
1049 if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1050 a = calloc(1, sizeof(*a) + clid_len);
1051 if (a) {
1052 a->clid_len = clid_len;
1053 a->iaid = ia->iaid;
1054 a->length = reqlen;
1055 a->peer = *addr;
1056 a->assigned = reqhint;
1057
1058 if (first)
1059 memcpy(a->key, first->key, sizeof(a->key));
1060 else
1061 odhcpd_urandom(a->key, sizeof(a->key));
1062 memcpy(a->clid_data, clid_data, clid_len);
1063
1064 if (is_pd)
1065 while (!(assigned = assign_pd(iface, a)) &&
1066 !a->managed_size && ++a->length <= 64);
1067 else
1068 assigned = assign_na(iface, a);
1069
1070 if (a->managed_size && !assigned)
1071 return -1;
1072 }
1073 }
1074
1075 if (!assigned || iface->ia_addr_len == 0) { // Set error status
1076 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1077 } else if (assigned && !first) { //
1078 size_t handshake_len = 4;
1079 buf[0] = 0;
1080 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1081 buf[2] = 0;
1082 buf[3] = 0;
1083
1084 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1085 struct dhcpv6_auth_reconfigure auth = {
1086 htons(DHCPV6_OPT_AUTH),
1087 htons(sizeof(auth) - 4),
1088 3, 1, 0,
1089 {htonl(time(NULL)), htonl(++serial)},
1090 1,
1091 {0}
1092 };
1093 memcpy(auth.key, a->key, sizeof(a->key));
1094 memcpy(buf + handshake_len, &auth, sizeof(auth));
1095 handshake_len += sizeof(auth);
1096 }
1097
1098 buf += handshake_len;
1099 buflen -= handshake_len;
1100 response_len += handshake_len;
1101
1102 first = a;
1103 }
1104
1105 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1106
1107 // Was only a solicitation: mark binding for removal
1108 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1109 a->valid_until = 0;
1110 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1111 if (hostname_len > 0) {
1112 a->hostname = realloc(a->hostname, hostname_len + 1);
1113 if (a->hostname) {
1114 memcpy(a->hostname, hostname, hostname_len);
1115 a->hostname[hostname_len] = 0;
1116 }
1117 }
1118 a->accept_reconf = accept_reconf;
1119 apply_lease(iface, a, true);
1120 } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1121 free_dhcpv6_assignment(a);
1122 }
1123 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1124 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1125 hdr->msg_type == DHCPV6_MSG_REBIND ||
1126 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1127 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1128 status = DHCPV6_STATUS_NOBINDING;
1129 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1130 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1131 hdr->msg_type == DHCPV6_MSG_REBIND) {
1132 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1133 if (a)
1134 apply_lease(iface, a, true);
1135 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1136 a->valid_until = 0;
1137 apply_lease(iface, a, false);
1138 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1139 a->clid_len = 0;
1140 a->valid_until = now + 3600; // Block address for 1h
1141 }
1142 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1143 // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1144 status = DHCPV6_STATUS_NOTONLINK;
1145 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1146 notonlink = true;
1147 }
1148
1149 buf += ia_response_len;
1150 buflen -= ia_response_len;
1151 response_len += ia_response_len;
1152 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1153 }
1154
1155 if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1156 response_len + 6 < buflen) {
1157 buf[0] = 0;
1158 buf[1] = DHCPV6_OPT_STATUS;
1159 buf[2] = 0;
1160 buf[3] = 2;
1161 buf[4] = 0;
1162 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1163 response_len += 6;
1164 }
1165
1166 dhcpv6_write_statefile();
1167
1168 out:
1169 return response_len;
1170 }
OpenWrt DHCP Server