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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 <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 if (lease->dhcpv4_leasetime > 0)
104 a->leasetime = lease->dhcpv4_leasetime;
105
106 a->clid_len = duid_len;
107 a->length = 128;
108 if (lease->hostid) {
109 a->assigned = lease->hostid;
110 } else {
111 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
112 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
113 }
114 odhcpd_urandom(a->key, sizeof(a->key));
115 memcpy(a->clid_data, lease->duid, lease->duid_len);
116 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
117 /* Infinite valid */
118 a->valid_until = 0;
119
120 // Assign to all interfaces
121 struct dhcpv6_assignment *c;
122 list_for_each_entry(c, &iface->ia_assignments, head) {
123 if (c->length != 128 || c->assigned > a->assigned) {
124 list_add_tail(&a->head, &c->head);
125 break;
126 } else if (c->assigned == a->assigned) {
127 // Already an assignment with that number
128 break;
129 }
130 }
131
132 if (a->head.next) {
133 if (lease->hostname[0]) {
134 free(a->hostname);
135 a->hostname = strdup(lease->hostname);
136 }
137 } else {
138 free(a->hostname);
139 free(a);
140 }
141 }
142 }
143 return 0;
144 }
145
146
147 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
148 {
149 struct {
150 struct dhcpv6_client_header hdr;
151 uint16_t srvid_type;
152 uint16_t srvid_len;
153 uint16_t duid_type;
154 uint16_t hardware_type;
155 uint8_t mac[6];
156 uint16_t msg_type;
157 uint16_t msg_len;
158 uint8_t msg_id;
159 struct dhcpv6_auth_reconfigure auth;
160 uint16_t clid_type;
161 uint16_t clid_len;
162 uint8_t clid_data[128];
163 } __attribute__((packed)) reconf_msg = {
164 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
165 .srvid_type = htons(DHCPV6_OPT_SERVERID),
166 .srvid_len = htons(10),
167 .duid_type = htons(3),
168 .hardware_type = htons(1),
169 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
170 .msg_len = htons(1),
171 .msg_id = DHCPV6_MSG_RENEW,
172 .auth = {htons(DHCPV6_OPT_AUTH),
173 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
174 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
175 .clid_type = htons(DHCPV6_OPT_CLIENTID),
176 .clid_len = htons(assign->clid_len),
177 .clid_data = {0},
178 };
179
180 odhcpd_get_mac(iface, reconf_msg.mac);
181 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
182 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
183
184 md5_ctx_t md5;
185 uint8_t secretbytes[64];
186 memset(secretbytes, 0, sizeof(secretbytes));
187 memcpy(secretbytes, assign->key, sizeof(assign->key));
188
189 for (size_t i = 0; i < sizeof(secretbytes); ++i)
190 secretbytes[i] ^= 0x36;
191
192 md5_begin(&md5);
193 md5_hash(secretbytes, sizeof(secretbytes), &md5);
194 md5_hash(iov.iov_base, iov.iov_len, &md5);
195 md5_end(reconf_msg.auth.key, &md5);
196
197 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
198 secretbytes[i] ^= 0x36;
199 secretbytes[i] ^= 0x5c;
200 }
201
202 md5_begin(&md5);
203 md5_hash(secretbytes, sizeof(secretbytes), &md5);
204 md5_hash(reconf_msg.auth.key, 16, &md5);
205 md5_end(reconf_msg.auth.key, &md5);
206
207 return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
208 }
209
210
211 void dhcpv6_write_statefile(void)
212 {
213 md5_ctx_t md5;
214 md5_begin(&md5);
215
216 if (config.dhcp_statefile) {
217 time_t now = odhcpd_time(), wall_time = time(NULL);
218 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
219 if (fd < 0)
220 return;
221
222 lockf(fd, F_LOCK, 0);
223 if (ftruncate(fd, 0) < 0) {}
224
225 FILE *fp = fdopen(fd, "w");
226 if (!fp) {
227 close(fd);
228 return;
229 }
230
231 struct interface *iface;
232 list_for_each_entry(iface, &interfaces, head) {
233 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
234 continue;
235
236 if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
237 struct dhcpv6_assignment *c;
238 list_for_each_entry(c, &iface->ia_assignments, head) {
239 if (c->clid_len == 0 || c->managed_size < 0)
240 continue;
241
242 char ipbuf[INET6_ADDRSTRLEN];
243 char leasebuf[512];
244 char duidbuf[264];
245 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
246
247 // iface DUID iaid hostname lifetime assigned length [addrs...]
248 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
249 iface->ifname, duidbuf, ntohl(c->iaid),
250 (c->hostname ? c->hostname : "-"),
251 (c->valid_until > now ?
252 (c->valid_until - now + wall_time) :
253 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
254 c->assigned, (unsigned)c->length);
255
256 struct in6_addr addr;
257 struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
258 size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
259 size_t m = 0;
260
261 for (size_t i = 0; i < addrlen; ++i)
262 if (addrs[i].preferred > addrs[m].preferred ||
263 (addrs[i].preferred == addrs[m].preferred &&
264 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
265 m = i;
266
267 for (size_t i = 0; i < addrlen; ++i) {
268 if (addrs[i].prefix > 96 || (!INFINITE_VALID(c->valid_until) && c->valid_until <= now) ||
269 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
270 addrs[i].prefix == 64))
271 continue;
272
273 addr = addrs[i].addr;
274 if (c->length == 128)
275 addr.s6_addr32[3] = htonl(c->assigned);
276 else
277 addr.s6_addr32[1] |= htonl(c->assigned);
278
279 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
280
281 if (c->length == 128 && c->hostname) {
282 fputs(ipbuf, fp);
283
284 char b[256];
285 if (dn_expand(iface->search, iface->search + iface->search_len,
286 iface->search, b, sizeof(b)) > 0)
287 fprintf(fp, "\t%s.%s", c->hostname, b);
288
289 fprintf(fp, "\t%s\n", c->hostname);
290 md5_hash(ipbuf, strlen(ipbuf), &md5);
291 md5_hash(c->hostname, strlen(c->hostname), &md5);
292 }
293
294 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
295 (c->managed_size) ? addrs[i].prefix : c->length);
296 }
297 leasebuf[l - 1] = '\n';
298 fwrite(leasebuf, 1, l, fp);
299 }
300 }
301
302 if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
303 struct dhcpv4_assignment *c;
304 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
305 char ipbuf[INET6_ADDRSTRLEN];
306 char leasebuf[512];
307 char duidbuf[16];
308 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
309
310 // iface DUID iaid hostname lifetime assigned length [addrs...]
311 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
312 iface->ifname, duidbuf,
313 (c->hostname ? c->hostname : "-"),
314 (c->valid_until > now ?
315 (c->valid_until - now + wall_time) :
316 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
317 c->addr);
318
319 struct in_addr addr = {htonl(c->addr)};
320 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
321
322 if (c->hostname[0]) {
323 fputs(ipbuf, fp);
324
325 char b[256];
326 if (dn_expand(iface->search, iface->search + iface->search_len,
327 iface->search, b, sizeof(b)) > 0)
328 fprintf(fp, "\t%s.%s", c->hostname, b);
329
330 fprintf(fp, "\t%s\n", c->hostname);
331 md5_hash(ipbuf, strlen(ipbuf), &md5);
332 md5_hash(c->hostname, strlen(c->hostname), &md5);
333 }
334
335 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
336 leasebuf[l - 1] = '\n';
337 fwrite(leasebuf, 1, l, fp);
338 }
339 }
340 }
341
342 fclose(fp);
343 }
344
345 uint8_t newmd5[16];
346 md5_end(newmd5, &md5);
347
348 if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
349 memcpy(statemd5, newmd5, sizeof(statemd5));
350 char *argv[2] = {config.dhcp_cb, NULL};
351 if (!vfork()) {
352 execv(argv[0], argv);
353 _exit(128);
354 }
355 }
356 }
357
358
359 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
360 {
361 if (a->length > 64 || a->managed_size < 0)
362 return;
363
364 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
365 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
366
367 for (size_t i = 0; i < addrlen; ++i) {
368 struct in6_addr prefix = addrs[i].addr;
369 prefix.s6_addr32[1] |= htonl(a->assigned);
370 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
371 iface, &a->peer.sin6_addr, 1024, add);
372 }
373 }
374
375
376 // More data was received from TCP connection
377 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
378 {
379 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
380 time_t now = odhcpd_time();
381 bool first = c->managed_size < 0;
382
383 for (;;) {
384 int pending;
385 char *data = ustream_get_read_buf(s, &pending);
386 char *end = memmem(data, pending, "\n\n", 2);
387
388 if (!end)
389 break;
390
391 end += 2;
392 end[-1] = 0;
393
394 c->managed_size = 0;
395 if (c->accept_reconf)
396 c->reconf_cnt = 1;
397
398 char *saveptr;
399 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
400 c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
401 struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
402
403 char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
404 if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
405 continue;
406
407 x = strtok_r(NULL, ",", &saveptr2);
408 if (sscanf(x, "%hhu", &n->prefix) < 1)
409 continue;
410
411 x = strtok_r(NULL, ",", &saveptr2);
412 if (sscanf(x, "%u", &n->preferred) < 1)
413 continue;
414
415 x = strtok_r(NULL, ",", &saveptr2);
416 if (sscanf(x, "%u", &n->valid) < 1)
417 continue;
418
419 if (n->preferred > n->valid)
420 continue;
421
422 if (UINT32_MAX - now < n->preferred)
423 n->preferred = UINT32_MAX;
424 else
425 n->preferred += now;
426
427 if (UINT32_MAX - now < n->valid)
428 n->valid = UINT32_MAX;
429 else
430 n->valid += now;
431
432 n->dprefix = 0;
433
434 ++c->managed_size;
435 }
436
437 ustream_consume(s, end - data);
438 }
439
440 if (first && c->managed_size == 0)
441 free_dhcpv6_assignment(c);
442 else if (first)
443 c->valid_until = now + 150;
444 }
445
446
447 // TCP transmission has ended, either because of success or timeout or other error
448 static void managed_handle_pd_done(struct ustream *s)
449 {
450 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
451 c->valid_until = odhcpd_time() + 15;
452 c->managed_size = 0;
453 if (c->accept_reconf)
454 c->reconf_cnt = 1;
455 }
456
457
458
459 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
460 {
461 struct dhcpv6_assignment *c;
462
463 if (iface->dhcpv6_pd_manager[0]) {
464 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
465 if (fd >= 0) {
466 char iaidbuf[298];
467 odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
468
469 assign->managed_sock.stream.notify_read = managed_handle_pd_data;
470 assign->managed_sock.stream.notify_state = managed_handle_pd_done;
471 ustream_fd_init(&assign->managed_sock, fd);
472 ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
473 iaidbuf, assign->iaid, assign->length);
474 ustream_write_pending(&assign->managed_sock.stream);
475 assign->managed_size = -1;
476 assign->valid_until = odhcpd_time() + 15;
477 list_add(&assign->head, &iface->ia_assignments);
478
479 // Wait initial period of up to 250ms for immediate assignment
480 struct pollfd pfd = { .fd = fd, .events = POLLIN };
481 poll(&pfd, 1, 250);
482 managed_handle_pd_data(&assign->managed_sock.stream, 0);
483
484 if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
485 return true;
486 }
487
488 return false;
489 } else if (iface->ia_addr_len < 1) {
490 return false;
491 }
492
493 // Try honoring the hint first
494 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
495 if (assign->assigned) {
496 list_for_each_entry(c, &iface->ia_assignments, head) {
497 if (c->length == 128 || c->length == 0)
498 continue;
499
500 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
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
511 // Fallback to a variable assignment
512 current = 1;
513 list_for_each_entry(c, &iface->ia_assignments, head) {
514 if (c->length == 128 || c->length == 0)
515 continue;
516
517 current = (current + asize) & (~asize);
518 if (current + asize < c->assigned) {
519 assign->assigned = current;
520 list_add_tail(&assign->head, &c->head);
521 apply_lease(iface, assign, true);
522 return true;
523 }
524
525 if (c->assigned != 0)
526 current = (c->assigned + (1 << (64 - c->length)));
527 }
528
529 return false;
530 }
531
532
533 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
534 {
535 // Seed RNG with checksum of DUID
536 uint32_t seed = 0;
537 for (size_t i = 0; i < assign->clid_len; ++i)
538 seed += assign->clid_data[i];
539 srand(seed);
540
541 // Try to assign up to 100x
542 for (size_t i = 0; i < 100; ++i) {
543 uint32_t try;
544 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
545
546 struct dhcpv6_assignment *c;
547 list_for_each_entry(c, &iface->ia_assignments, head) {
548 if (c->length == 0)
549 continue;
550
551 if (c->assigned > try || c->length != 128) {
552 assign->assigned = try;
553 list_add_tail(&assign->head, &c->head);
554 return true;
555 } else if (c->assigned == try) {
556 break;
557 }
558 }
559 }
560
561 return false;
562 }
563
564 void dhcpv6_ia_preupdate(struct interface *iface)
565 {
566 if (iface->dhcpv6 != RELAYD_SERVER)
567 return;
568
569 struct dhcpv6_assignment *c, *border = list_last_entry(
570 &iface->ia_assignments, struct dhcpv6_assignment, head);
571 list_for_each_entry(c, &iface->ia_assignments, head)
572 if (c != border && !iface->managed)
573 apply_lease(iface, c, false);
574 }
575
576 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
577 {
578 if (iface->dhcpv6 != RELAYD_SERVER)
579 return;
580
581 int minprefix = -1;
582 for (size_t i = 0; i < iface->ia_addr_len; ++i) {
583 if (iface->ia_addr[i].preferred > (uint32_t)now &&
584 iface->ia_addr[i].prefix < 64 &&
585 iface->ia_addr[i].prefix > minprefix)
586 minprefix = iface->ia_addr[i].prefix;
587 }
588
589 struct dhcpv6_assignment *border = list_last_entry(
590 &iface->ia_assignments, struct dhcpv6_assignment, head);
591 if (minprefix > 32 && minprefix <= 64)
592 border->assigned = 1U << (64 - minprefix);
593 else
594 border->assigned = 0;
595
596 struct list_head reassign = LIST_HEAD_INIT(reassign);
597 struct dhcpv6_assignment *c, *d;
598 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
599 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
600 c->managed_size)
601 continue;
602
603 if (c->length < 128 && c->assigned >= border->assigned && c != border)
604 list_move(&c->head, &reassign);
605 else if (c != border)
606 apply_lease(iface, c, true);
607
608 if (c->accept_reconf && c->reconf_cnt == 0) {
609 c->reconf_cnt = 1;
610 c->reconf_sent = now;
611 send_reconf(iface, c);
612
613 // Leave all other assignments of that client alone
614 struct dhcpv6_assignment *a;
615 list_for_each_entry(a, &iface->ia_assignments, head)
616 if (a != c && a->clid_len == c->clid_len &&
617 !memcmp(a->clid_data, c->clid_data, a->clid_len))
618 c->reconf_cnt = INT_MAX;
619 }
620 }
621
622 while (!list_empty(&reassign)) {
623 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
624 list_del(&c->head);
625 if (!assign_pd(iface, c)) {
626 c->assigned = 0;
627 list_add(&c->head, &iface->ia_assignments);
628 }
629 }
630
631 dhcpv6_write_statefile();
632 }
633
634
635 static void reconf_timer(struct uloop_timeout *event)
636 {
637 time_t now = odhcpd_time();
638 struct interface *iface;
639 list_for_each_entry(iface, &interfaces, head) {
640 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
641 continue;
642
643 struct dhcpv6_assignment *a, *n;
644 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
645 if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
646 if ((a->length < 128 && a->clid_len > 0) ||
647 (a->length == 128 && a->clid_len == 0)) {
648 list_del(&a->head);
649 free_dhcpv6_assignment(a);
650 }
651 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
652 now > a->reconf_sent + (1 << a->reconf_cnt)) {
653 ++a->reconf_cnt;
654 a->reconf_sent = now;
655 send_reconf(iface, a);
656 }
657 }
658 }
659 uloop_timeout_set(event, 2000);
660 }
661
662
663 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
664 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
665 struct interface *iface, bool request)
666 {
667 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
668 return 0;
669
670 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
671 size_t datalen = sizeof(out);
672 time_t now = odhcpd_time();
673
674 if (status) {
675 struct __attribute__((packed)) {
676 uint16_t type;
677 uint16_t len;
678 uint16_t value;
679 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
680 htons(status)};
681
682 memcpy(buf + datalen, &stat, sizeof(stat));
683 datalen += sizeof(stat);
684 } else {
685 if (a) {
686 uint32_t leasetime;
687 if (a->leasetime > 0) {
688 leasetime = a->leasetime;
689 } else {
690 leasetime = iface->dhcpv4_leasetime;
691 }
692 if (leasetime == 0)
693 leasetime = 3600;
694 else if (leasetime < 60)
695 leasetime = 60;
696
697 uint32_t pref = leasetime;
698 uint32_t valid = leasetime;
699
700 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
701 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
702 size_t m = 0;
703
704 for (size_t i = 0; i < addrlen; ++i)
705 if (addrs[i].preferred > addrs[m].preferred ||
706 (addrs[i].preferred == addrs[m].preferred &&
707 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
708 m = i;
709
710 for (size_t i = 0; i < addrlen; ++i) {
711 uint32_t prefix_pref = addrs[i].preferred;
712 uint32_t prefix_valid = addrs[i].valid;
713
714 if (addrs[i].prefix > 96 ||
715 addrs[i].preferred <= (uint32_t)now)
716 continue;
717
718 if (prefix_pref != UINT32_MAX)
719 prefix_pref -= now;
720
721 if (prefix_valid != UINT32_MAX)
722 prefix_valid -= now;
723
724 if (a->length < 128) {
725 struct dhcpv6_ia_prefix p = {
726 .type = htons(DHCPV6_OPT_IA_PREFIX),
727 .len = htons(sizeof(p) - 4),
728 .preferred = htonl(prefix_pref),
729 .valid = htonl(prefix_valid),
730 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
731 .addr = addrs[i].addr
732 };
733 p.addr.s6_addr32[1] |= htonl(a->assigned);
734
735 size_t entrlen = sizeof(p) - 4;
736
737 if (datalen + entrlen + 4 > buflen ||
738 (a->assigned == 0 && a->managed_size == 0) ||
739 (!a->managed_size && a->length <= addrs[i].prefix))
740 continue;
741
742 memcpy(buf + datalen, &p, sizeof(p));
743 datalen += entrlen + 4;
744 } else {
745 struct dhcpv6_ia_addr n = {
746 .type = htons(DHCPV6_OPT_IA_ADDR),
747 .len = htons(sizeof(n) - 4),
748 .addr = addrs[i].addr,
749 .preferred = htonl(prefix_pref),
750 .valid = htonl(prefix_valid)
751 };
752 n.addr.s6_addr32[3] = htonl(a->assigned);
753 size_t entrlen = sizeof(n) - 4;
754
755 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
756 addrs[i].prefix <= 64)
757 continue;
758
759 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
760 continue;
761
762 memcpy(buf + datalen, &n, sizeof(n));
763 datalen += entrlen + 4;
764 }
765
766 // Calculate T1 / T2 based on non-deprecated addresses
767 if (prefix_pref > 0) {
768 if (prefix_pref < pref)
769 pref = prefix_pref;
770
771 if (prefix_valid < valid)
772 valid = prefix_valid;
773 }
774 }
775
776 /* UINT32_MAX is considered as infinite leasetime */
777 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
778 out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
779 out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
780
781 if (!out.t1)
782 out.t1 = htonl(1);
783
784 if (!out.t2)
785 out.t2 = htonl(1);
786 }
787
788 if (!request) {
789 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
790 uint16_t otype, olen;
791 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
792 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
793 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
794 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
795 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
796 continue;
797
798 bool found = false;
799 if (a) {
800 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
801 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
802
803 for (size_t i = 0; i < addrlen; ++i) {
804 if (addrs[i].prefix > 96 ||
805 addrs[i].preferred <= (uint32_t)now)
806 continue;
807
808 struct in6_addr addr = addrs[i].addr;
809 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
810 addr.s6_addr32[1] |= htonl(a->assigned);
811
812 if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
813 p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
814 found = true;
815 } else {
816 addr.s6_addr32[3] = htonl(a->assigned);
817
818 if (!memcmp(&n->addr, &addr, sizeof(addr)))
819 found = true;
820 }
821 }
822 }
823
824 if (!found) {
825 if (otype == DHCPV6_OPT_IA_PREFIX) {
826 struct dhcpv6_ia_prefix inv = {
827 .type = htons(DHCPV6_OPT_IA_PREFIX),
828 .len = htons(sizeof(inv) - 4),
829 .preferred = 0,
830 .valid = 0,
831 .prefix = p->prefix,
832 .addr = p->addr
833 };
834
835 if (datalen + sizeof(inv) > buflen)
836 continue;
837
838 memcpy(buf + datalen, &inv, sizeof(inv));
839 datalen += sizeof(inv);
840 } else {
841 struct dhcpv6_ia_addr inv = {
842 .type = htons(DHCPV6_OPT_IA_ADDR),
843 .len = htons(sizeof(inv) - 4),
844 .addr = n->addr,
845 .preferred = 0,
846 .valid = 0
847 };
848
849 if (datalen + sizeof(inv) > buflen)
850 continue;
851
852 memcpy(buf + datalen, &inv, sizeof(inv));
853 datalen += sizeof(inv);
854 }
855 }
856 }
857 }
858 }
859
860 out.len = htons(datalen - 4);
861 memcpy(buf, &out, sizeof(out));
862 return datalen;
863 }
864
865
866 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
867 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
868 {
869 const char *type = "UNKNOWN";
870 const char *status = "UNKNOWN";
871
872 if (msgtype == DHCPV6_MSG_RENEW)
873 return;
874
875 switch (msgtype) {
876 case DHCPV6_MSG_SOLICIT:
877 type = "SOLICIT";
878 break;
879 case DHCPV6_MSG_REQUEST:
880 type = "REQUEST";
881 break;
882 case DHCPV6_MSG_CONFIRM:
883 type = "CONFIRM";
884 break;
885 case DHCPV6_MSG_RENEW:
886 type = "RENEW";
887 break;
888 case DHCPV6_MSG_REBIND:
889 type = "REBIND";
890 break;
891 case DHCPV6_MSG_RELEASE:
892 type = "RELEASE";
893 break;
894 case DHCPV6_MSG_DECLINE:
895 type = "DECLINE";
896 break;
897 }
898
899 switch (code) {
900 case DHCPV6_STATUS_OK:
901 status = "ok";
902 break;
903 case DHCPV6_STATUS_NOADDRSAVAIL:
904 status = "no addresses available";
905 break;
906 case DHCPV6_STATUS_NOBINDING:
907 status = "no binding";
908 break;
909 case DHCPV6_STATUS_NOTONLINK:
910 status = "not on-link";
911 break;
912 case DHCPV6_STATUS_NOPREFIXAVAIL:
913 status = "no prefix available";
914 break;
915 }
916
917 char leasebuf[256] = "";
918
919 if (a) {
920 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
921 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
922 size_t lbsize = 0;
923 char addrbuf[INET6_ADDRSTRLEN];
924
925 for (size_t i = 0; i < addrlen; ++i) {
926 if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
927 continue;
928
929 struct in6_addr addr = addrs[i].addr;
930 int prefix = a->managed ? addrs[i].prefix : a->length;
931 if (prefix == 128)
932 addr.s6_addr32[3] = htonl(a->assigned);
933 else
934 addr.s6_addr32[1] |= htonl(a->assigned);
935
936 inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
937 lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
938 }
939 }
940
941 syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
942 duidbuf, iface->ifname, status, leasebuf);
943 }
944
945
946
947 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
948 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
949 {
950 time_t now = odhcpd_time();
951 size_t response_len = 0;
952 const struct dhcpv6_client_header *hdr = data;
953 uint8_t *start = (uint8_t*)&hdr[1], *odata;
954 uint16_t otype, olen;
955
956 // Find and parse client-id and hostname
957 bool accept_reconf = false;
958 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
959 char hostname[256];
960 size_t hostname_len = 0;
961 bool notonlink = false;
962 char duidbuf[261];
963
964 dhcpv6_for_each_option(start, end, otype, olen, odata) {
965 if (otype == DHCPV6_OPT_CLIENTID) {
966 clid_data = odata;
967 clid_len = olen;
968
969 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
970 memcpy(mac, &odata[8], sizeof(mac));
971 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
972 memcpy(mac, &odata[4], sizeof(mac));
973
974 if (olen <= 130)
975 odhcpd_hexlify(duidbuf, odata, olen);
976 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
977 uint8_t fqdn_buf[256];
978 memcpy(fqdn_buf, odata, olen);
979 fqdn_buf[olen++] = 0;
980
981 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
982 hostname_len = strcspn(hostname, ".");
983 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
984 accept_reconf = true;
985 }
986 }
987
988 if (!clid_data || !clid_len || clid_len > 130)
989 goto out;
990
991 struct dhcpv6_assignment *first = NULL;
992 dhcpv6_for_each_option(start, end, otype, olen, odata) {
993 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
994 bool is_na = (otype == DHCPV6_OPT_IA_NA);
995 bool ia_addr_present = false;
996 if (!is_pd && !is_na)
997 continue;
998
999 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1000 size_t ia_response_len = 0;
1001 uint8_t reqlen = (is_pd) ? 62 : 128;
1002 uint32_t reqhint = 0;
1003
1004 // Parse request hint for IA-PD
1005 if (is_pd) {
1006 uint8_t *sdata;
1007 uint16_t stype, slen;
1008 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1009 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1010 continue;
1011
1012 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1013 if (p->prefix) {
1014 reqlen = p->prefix;
1015 reqhint = ntohl(p->addr.s6_addr32[1]);
1016 if (reqlen > 32 && reqlen <= 64)
1017 reqhint &= (1U << (64 - reqlen)) - 1;
1018 }
1019 }
1020
1021 if (reqlen > 64)
1022 reqlen = 64;
1023 } else if (is_na) {
1024 uint8_t *sdata;
1025 uint16_t stype, slen;
1026 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1027 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1028 continue;
1029
1030 ia_addr_present = true;
1031 }
1032 }
1033
1034 // Find assignment
1035 struct dhcpv6_assignment *c, *a = NULL;
1036 list_for_each_entry(c, &iface->ia_assignments, head) {
1037 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1038 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1039 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1040 (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1041 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1042 a = c;
1043
1044 // Reset state
1045 apply_lease(iface, a, false);
1046 memcpy(a->clid_data, clid_data, clid_len);
1047 a->clid_len = clid_len;
1048 a->iaid = ia->iaid;
1049 a->peer = *addr;
1050 a->reconf_cnt = 0;
1051 a->reconf_sent = 0;
1052 break;
1053 }
1054 }
1055
1056 // Generic message handling
1057 uint16_t status = DHCPV6_STATUS_OK;
1058 if (a && a->managed_size < 0) {
1059 return -1;
1060 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1061 bool assigned = !!a;
1062
1063 if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1064 a = calloc(1, sizeof(*a) + clid_len);
1065 if (a) {
1066 a->clid_len = clid_len;
1067 a->iaid = ia->iaid;
1068 a->length = reqlen;
1069 a->peer = *addr;
1070 a->assigned = reqhint;
1071
1072 if (first)
1073 memcpy(a->key, first->key, sizeof(a->key));
1074 else
1075 odhcpd_urandom(a->key, sizeof(a->key));
1076 memcpy(a->clid_data, clid_data, clid_len);
1077
1078 if (is_pd)
1079 while (!(assigned = assign_pd(iface, a)) &&
1080 !a->managed_size && ++a->length <= 64);
1081 else
1082 assigned = assign_na(iface, a);
1083
1084 if (a->managed_size && !assigned)
1085 return -1;
1086 }
1087 }
1088
1089 if (!assigned || iface->ia_addr_len == 0) { // Set error status
1090 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1091 } else if (assigned && !first) { //
1092 size_t handshake_len = 4;
1093 buf[0] = 0;
1094 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1095 buf[2] = 0;
1096 buf[3] = 0;
1097
1098 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1099 struct dhcpv6_auth_reconfigure auth = {
1100 htons(DHCPV6_OPT_AUTH),
1101 htons(sizeof(auth) - 4),
1102 3, 1, 0,
1103 {htonl(time(NULL)), htonl(++serial)},
1104 1,
1105 {0}
1106 };
1107 memcpy(auth.key, a->key, sizeof(a->key));
1108 memcpy(buf + handshake_len, &auth, sizeof(auth));
1109 handshake_len += sizeof(auth);
1110 }
1111
1112 buf += handshake_len;
1113 buflen -= handshake_len;
1114 response_len += handshake_len;
1115
1116 first = a;
1117 }
1118
1119 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1120
1121 // Was only a solicitation: mark binding for removal
1122 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1123 a->valid_until = now;
1124 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1125 if (hostname_len > 0) {
1126 a->hostname = realloc(a->hostname, hostname_len + 1);
1127 if (a->hostname) {
1128 memcpy(a->hostname, hostname, hostname_len);
1129 a->hostname[hostname_len] = 0;
1130 }
1131 }
1132 a->accept_reconf = accept_reconf;
1133 apply_lease(iface, a, true);
1134 } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1135 free_dhcpv6_assignment(a);
1136 }
1137 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1138 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1139 hdr->msg_type == DHCPV6_MSG_REBIND ||
1140 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1141 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1142 status = DHCPV6_STATUS_NOBINDING;
1143 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1144 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1145 hdr->msg_type == DHCPV6_MSG_REBIND) {
1146 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1147 if (a)
1148 apply_lease(iface, a, true);
1149 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1150 a->valid_until = now - 1;
1151 apply_lease(iface, a, false);
1152 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1153 a->clid_len = 0;
1154 a->valid_until = now + 3600; // Block address for 1h
1155 }
1156 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1157 // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1158 status = DHCPV6_STATUS_NOTONLINK;
1159 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1160 notonlink = true;
1161 }
1162
1163 buf += ia_response_len;
1164 buflen -= ia_response_len;
1165 response_len += ia_response_len;
1166 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1167 }
1168
1169 if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1170 response_len + 6 < buflen) {
1171 buf[0] = 0;
1172 buf[1] = DHCPV6_OPT_STATUS;
1173 buf[2] = 0;
1174 buf[3] = 2;
1175 buf[4] = 0;
1176 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1177 response_len += 6;
1178 }
1179
1180 dhcpv6_write_statefile();
1181
1182 out:
1183 return response_len;
1184 }
OpenWrt DHCP Server