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