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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 update(struct interface *iface);
38 static void reconf_timer(struct uloop_timeout *event);
39 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
40 static uint32_t serial = 0;
41 static uint8_t statemd5[16];
42
43
44 int dhcpv6_ia_init(void)
45 {
46 uloop_timeout_set(&reconf_event, 2000);
47 return 0;
48 }
49
50
51 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
52 {
53 if (c->managed_sock.fd.registered) {
54 ustream_free(&c->managed_sock.stream);
55 close(c->managed_sock.fd.fd);
56 }
57
58 if (c->head.next)
59 list_del(&c->head);
60
61 free(c->managed);
62 free(c->hostname);
63 free(c);
64 }
65
66
67 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
68 {
69 if (!enable && iface->ia_assignments.next) {
70 struct dhcpv6_assignment *c;
71 while (!list_empty(&iface->ia_assignments)) {
72 c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
73 free_dhcpv6_assignment(c);
74 }
75 }
76
77 if (enable && iface->dhcpv6 == RELAYD_SERVER) {
78 if (!iface->ia_assignments.next)
79 INIT_LIST_HEAD(&iface->ia_assignments);
80
81 if (list_empty(&iface->ia_assignments)) {
82 struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
83 if (!border) {
84 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
85 return -1;
86 }
87
88 border->length = 64;
89 list_add(&border->head, &iface->ia_assignments);
90 }
91
92 update(iface);
93
94 // Parse static entries
95 struct lease *lease;
96 list_for_each_entry(lease, &leases, head) {
97 // Construct entry
98 struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
99 if (!a) {
100 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
101 iface->ifname);
102 return -1;
103 }
104
105 a->clid_len = lease->duid_len;
106 a->length = 128;
107 if (lease->hostid) {
108 a->assigned = lease->hostid;
109 } else {
110 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
111 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
112 }
113 odhcpd_urandom(a->key, sizeof(a->key));
114 memcpy(a->clid_data, lease->duid, a->clid_len);
115 memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
116
117 // Assign to all interfaces
118 struct dhcpv6_assignment *c;
119 list_for_each_entry(c, &iface->ia_assignments, head) {
120 if (c->length != 128 || c->assigned > a->assigned) {
121 list_add_tail(&a->head, &c->head);
122 break;
123 } else if (c->assigned == a->assigned) {
124 // Already an assignment with that number
125 break;
126 }
127 }
128
129 if (a->head.next) {
130 if (lease->hostname[0]) {
131 free(a->hostname);
132 a->hostname = strdup(lease->hostname);
133 }
134 } else {
135 free(a->hostname);
136 free(a);
137 }
138 }
139 }
140 return 0;
141 }
142
143
144 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
145 {
146 struct {
147 struct dhcpv6_client_header hdr;
148 uint16_t srvid_type;
149 uint16_t srvid_len;
150 uint16_t duid_type;
151 uint16_t hardware_type;
152 uint8_t mac[6];
153 uint16_t msg_type;
154 uint16_t msg_len;
155 uint8_t msg_id;
156 struct dhcpv6_auth_reconfigure auth;
157 uint16_t clid_type;
158 uint16_t clid_len;
159 uint8_t clid_data[128];
160 } __attribute__((packed)) reconf_msg = {
161 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
162 .srvid_type = htons(DHCPV6_OPT_SERVERID),
163 .srvid_len = htons(10),
164 .duid_type = htons(3),
165 .hardware_type = htons(1),
166 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
167 .msg_len = htons(1),
168 .msg_id = DHCPV6_MSG_RENEW,
169 .auth = {htons(DHCPV6_OPT_AUTH),
170 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
171 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
172 .clid_type = htons(DHCPV6_OPT_CLIENTID),
173 .clid_len = htons(assign->clid_len),
174 .clid_data = {0},
175 };
176
177 odhcpd_get_mac(iface, reconf_msg.mac);
178 memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
179 struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
180
181 md5_ctx_t md5;
182 uint8_t secretbytes[64];
183 memset(secretbytes, 0, sizeof(secretbytes));
184 memcpy(secretbytes, assign->key, sizeof(assign->key));
185
186 for (size_t i = 0; i < sizeof(secretbytes); ++i)
187 secretbytes[i] ^= 0x36;
188
189 md5_begin(&md5);
190 md5_hash(secretbytes, sizeof(secretbytes), &md5);
191 md5_hash(iov.iov_base, iov.iov_len, &md5);
192 md5_end(reconf_msg.auth.key, &md5);
193
194 for (size_t i = 0; i < sizeof(secretbytes); ++i) {
195 secretbytes[i] ^= 0x36;
196 secretbytes[i] ^= 0x5c;
197 }
198
199 md5_begin(&md5);
200 md5_hash(secretbytes, sizeof(secretbytes), &md5);
201 md5_hash(reconf_msg.auth.key, 16, &md5);
202 md5_end(reconf_msg.auth.key, &md5);
203
204 return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
205 }
206
207
208 void dhcpv6_write_statefile(void)
209 {
210 md5_ctx_t md5;
211 md5_begin(&md5);
212
213 if (config.dhcp_statefile) {
214 time_t now = odhcpd_time(), wall_time = time(NULL);
215 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
216 if (fd < 0)
217 return;
218
219 lockf(fd, F_LOCK, 0);
220 if (ftruncate(fd, 0) < 0) {}
221
222 FILE *fp = fdopen(fd, "w");
223 if (!fp) {
224 close(fd);
225 return;
226 }
227
228 struct interface *iface;
229 list_for_each_entry(iface, &interfaces, head) {
230 if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
231 continue;
232
233 if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
234 struct dhcpv6_assignment *c;
235 list_for_each_entry(c, &iface->ia_assignments, head) {
236 if (c->clid_len == 0 || c->managed_size < 0)
237 continue;
238
239 char ipbuf[INET6_ADDRSTRLEN];
240 char leasebuf[512];
241 char duidbuf[264];
242 odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
243
244 // iface DUID iaid hostname lifetime assigned length [addrs...]
245 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
246 iface->ifname, duidbuf, ntohl(c->iaid),
247 (c->hostname ? c->hostname : "-"),
248 (unsigned)(c->valid_until > now ?
249 (c->valid_until - now + wall_time) : 0),
250 c->assigned, (unsigned)c->length);
251
252 struct in6_addr addr;
253 struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
254 size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
255 size_t m = 0;
256
257 for (size_t i = 0; i < addrlen; ++i)
258 if (addrs[i].preferred > addrs[m].preferred ||
259 (addrs[i].preferred == addrs[m].preferred &&
260 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
261 m = i;
262
263 for (size_t i = 0; i < addrlen; ++i) {
264 if (addrs[i].prefix > 96 || c->valid_until <= now ||
265 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
266 addrs[i].prefix == 64))
267 continue;
268
269 addr = addrs[i].addr;
270 if (c->length == 128)
271 addr.s6_addr32[3] = htonl(c->assigned);
272 else
273 addr.s6_addr32[1] |= htonl(c->assigned);
274
275 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
276
277 if (c->length == 128 && c->hostname) {
278 fputs(ipbuf, fp);
279
280 char b[256];
281 if (dn_expand(iface->search, iface->search + iface->search_len,
282 iface->search, b, sizeof(b)) > 0)
283 fprintf(fp, "\t%s.%s", c->hostname, b);
284
285 fprintf(fp, "\t%s\n", c->hostname);
286 md5_hash(ipbuf, strlen(ipbuf), &md5);
287 md5_hash(c->hostname, strlen(c->hostname), &md5);
288 }
289
290 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
291 (c->managed_size) ? addrs[i].prefix : c->length);
292 }
293 leasebuf[l - 1] = '\n';
294 fwrite(leasebuf, 1, l, fp);
295 }
296 }
297
298 if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
299 struct dhcpv4_assignment *c;
300 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
301 char ipbuf[INET6_ADDRSTRLEN];
302 char leasebuf[512];
303 char duidbuf[16];
304 odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
305
306 // iface DUID iaid hostname lifetime assigned length [addrs...]
307 int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
308 iface->ifname, duidbuf,
309 (c->hostname ? c->hostname : "-"),
310 (unsigned)(c->valid_until > now ?
311 (c->valid_until - now + wall_time) : 0),
312 c->addr);
313
314 struct in_addr addr = {htonl(c->addr)};
315 inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
316
317 if (c->hostname[0]) {
318 fputs(ipbuf, fp);
319
320 char b[256];
321 if (dn_expand(iface->search, iface->search + iface->search_len,
322 iface->search, b, sizeof(b)) > 0)
323 fprintf(fp, "\t%s.%s", c->hostname, b);
324
325 fprintf(fp, "\t%s\n", c->hostname);
326 md5_hash(ipbuf, strlen(ipbuf), &md5);
327 md5_hash(c->hostname, strlen(c->hostname), &md5);
328 }
329
330 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
331 leasebuf[l - 1] = '\n';
332 fwrite(leasebuf, 1, l, fp);
333 }
334 }
335 }
336
337 fclose(fp);
338 }
339
340 uint8_t newmd5[16];
341 md5_end(newmd5, &md5);
342
343 if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
344 memcpy(statemd5, newmd5, sizeof(statemd5));
345 char *argv[2] = {config.dhcp_cb, NULL};
346 if (!vfork()) {
347 execv(argv[0], argv);
348 _exit(128);
349 }
350 }
351 }
352
353
354 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
355 {
356 if (a->length > 64 || a->managed_size < 0)
357 return;
358
359 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
360 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
361
362 for (size_t i = 0; i < addrlen; ++i) {
363 struct in6_addr prefix = addrs[i].addr;
364 prefix.s6_addr32[1] |= htonl(a->assigned);
365 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
366 iface, &a->peer.sin6_addr, add);
367 }
368 }
369
370
371 // More data was received from TCP connection
372 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
373 {
374 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
375 time_t now = odhcpd_time();
376 bool first = c->managed_size < 0;
377
378 for (;;) {
379 int pending;
380 char *data = ustream_get_read_buf(s, &pending);
381 char *end = memmem(data, pending, "\n\n", 2);
382
383 if (!end)
384 break;
385
386 end += 2;
387 end[-1] = 0;
388
389 c->managed_size = 0;
390 if (c->accept_reconf)
391 c->reconf_cnt = 1;
392
393 char *saveptr;
394 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
395 c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
396 struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
397
398 char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
399 if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
400 continue;
401
402 x = strtok_r(NULL, ",", &saveptr2);
403 if (sscanf(x, "%hhu", &n->prefix) < 1)
404 continue;
405
406 x = strtok_r(NULL, ",", &saveptr2);
407 if (sscanf(x, "%u", &n->preferred) < 1)
408 continue;
409
410 x = strtok_r(NULL, ",", &saveptr2);
411 if (sscanf(x, "%u", &n->valid) < 1)
412 continue;
413
414 if (n->preferred > n->valid)
415 continue;
416
417 if (UINT32_MAX - now < n->preferred)
418 n->preferred = UINT32_MAX;
419 else
420 n->preferred += now;
421
422 if (UINT32_MAX - now < n->valid)
423 n->valid = UINT32_MAX;
424 else
425 n->valid += now;
426
427 n->dprefix = 0;
428
429 ++c->managed_size;
430 }
431
432 ustream_consume(s, end - data);
433 }
434
435 if (first && c->managed_size == 0)
436 free_dhcpv6_assignment(c);
437 else if (first)
438 c->valid_until = now + 150;
439 }
440
441
442 // TCP transmission has ended, either because of success or timeout or other error
443 static void managed_handle_pd_done(struct ustream *s)
444 {
445 struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
446 c->valid_until = odhcpd_time() + 15;
447 c->managed_size = 0;
448 if (c->accept_reconf)
449 c->reconf_cnt = 1;
450 }
451
452
453
454 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
455 {
456 struct dhcpv6_assignment *c;
457
458 if (iface->dhcpv6_pd_manager[0]) {
459 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
460 if (fd >= 0) {
461 char iaidbuf[298];
462 odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
463
464 assign->managed_sock.stream.notify_read = managed_handle_pd_data;
465 assign->managed_sock.stream.notify_state = managed_handle_pd_done;
466 ustream_fd_init(&assign->managed_sock, fd);
467 ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
468 iaidbuf, assign->iaid, assign->length);
469 ustream_write_pending(&assign->managed_sock.stream);
470 assign->managed_size = -1;
471 assign->valid_until = odhcpd_time() + 15;
472 list_add(&assign->head, &iface->ia_assignments);
473
474 // Wait initial period of up to 250ms for immediate assignment
475 struct pollfd pfd = { .fd = fd, .events = POLLIN };
476 poll(&pfd, 1, 250);
477 managed_handle_pd_data(&assign->managed_sock.stream, 0);
478
479 if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
480 return true;
481 }
482
483 return false;
484 } else if (iface->ia_addr_len < 1) {
485 return false;
486 }
487
488 // Try honoring the hint first
489 uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
490 if (assign->assigned) {
491 list_for_each_entry(c, &iface->ia_assignments, head) {
492 if (c->length == 128 || c->length == 0)
493 continue;
494
495 if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
496 list_add_tail(&assign->head, &c->head);
497 apply_lease(iface, assign, true);
498 return true;
499 }
500
501 if (c->assigned != 0)
502 current = (c->assigned + (1 << (64 - c->length)));
503 }
504 }
505
506 // Fallback to a variable assignment
507 current = 1;
508 list_for_each_entry(c, &iface->ia_assignments, head) {
509 if (c->length == 128 || c->length == 0)
510 continue;
511
512 current = (current + asize) & (~asize);
513 if (current + asize < c->assigned) {
514 assign->assigned = current;
515 list_add_tail(&assign->head, &c->head);
516 apply_lease(iface, assign, true);
517 return true;
518 }
519
520 if (c->assigned != 0)
521 current = (c->assigned + (1 << (64 - c->length)));
522 }
523
524 return false;
525 }
526
527
528 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
529 {
530 // Seed RNG with checksum of DUID
531 uint32_t seed = 0;
532 for (size_t i = 0; i < assign->clid_len; ++i)
533 seed += assign->clid_data[i];
534 srand(seed);
535
536 // Try to assign up to 100x
537 for (size_t i = 0; i < 100; ++i) {
538 uint32_t try;
539 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
540
541 struct dhcpv6_assignment *c;
542 list_for_each_entry(c, &iface->ia_assignments, head) {
543 if (c->length == 0)
544 continue;
545
546 if (c->assigned > try || c->length != 128) {
547 assign->assigned = try;
548 list_add_tail(&assign->head, &c->head);
549 return true;
550 } else if (c->assigned == try) {
551 break;
552 }
553 }
554 }
555
556 return false;
557 }
558
559
560 static int prefixcmp(const void *va, const void *vb)
561 {
562 const struct odhcpd_ipaddr *a = va, *b = vb;
563 uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
564 uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
565 return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
566 }
567
568
569 static void update(struct interface *iface)
570 {
571 struct odhcpd_ipaddr addr[8];
572 memset(addr, 0, sizeof(addr));
573 int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
574
575 if (len < 0)
576 return;
577
578 qsort(addr, len, sizeof(*addr), prefixcmp);
579
580 time_t now = odhcpd_time();
581 int minprefix = -1;
582
583 for (int i = 0; i < len; ++i) {
584 if (addr[i].preferred > 0 && addr[i].prefix < 64 &&
585 addr[i].prefix > minprefix)
586 minprefix = addr[i].prefix;
587
588 addr[i].addr.s6_addr32[3] = 0;
589
590 if (addr[i].preferred < UINT32_MAX - now)
591 addr[i].preferred += now;
592
593 if (addr[i].valid < UINT32_MAX - now)
594 addr[i].valid += now;
595 }
596
597 struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
598 if (minprefix > 32 && minprefix <= 64)
599 border->assigned = 1U << (64 - minprefix);
600 else
601 border->assigned = 0;
602
603 bool change = len != (int)iface->ia_addr_len;
604 for (int i = 0; !change && i < len; ++i)
605 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
606 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
607 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
608 (addr[i].valid > (uint32_t)now + 7200) !=
609 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
610 change = true;
611
612 if (change) {
613 struct dhcpv6_assignment *c;
614 list_for_each_entry(c, &iface->ia_assignments, head)
615 if (c != border && !iface->managed)
616 apply_lease(iface, c, false);
617 }
618
619 memcpy(iface->ia_addr, addr, len * sizeof(*addr));
620 iface->ia_addr_len = len;
621
622 if (change) { // Addresses / prefixes have changed
623 struct list_head reassign = LIST_HEAD_INIT(reassign);
624 struct dhcpv6_assignment *c, *d;
625 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
626 if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
627 continue;
628
629 if (c->length < 128 && c->assigned >= border->assigned && c != border)
630 list_move(&c->head, &reassign);
631 else if (c != border)
632 apply_lease(iface, c, true);
633
634 if (c->accept_reconf && c->reconf_cnt == 0) {
635 c->reconf_cnt = 1;
636 c->reconf_sent = now;
637 send_reconf(iface, c);
638
639 // Leave all other assignments of that client alone
640 struct dhcpv6_assignment *a;
641 list_for_each_entry(a, &iface->ia_assignments, head)
642 if (a != c && a->clid_len == c->clid_len &&
643 !memcmp(a->clid_data, c->clid_data, a->clid_len))
644 c->reconf_cnt = INT_MAX;
645 }
646 }
647
648 while (!list_empty(&reassign)) {
649 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
650 list_del(&c->head);
651 if (!assign_pd(iface, c)) {
652 c->assigned = 0;
653 list_add(&c->head, &iface->ia_assignments);
654 }
655 }
656
657 dhcpv6_write_statefile();
658 }
659 }
660
661
662 static void reconf_timer(struct uloop_timeout *event)
663 {
664 time_t now = odhcpd_time();
665 struct interface *iface;
666 list_for_each_entry(iface, &interfaces, head) {
667 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
668 continue;
669
670 struct dhcpv6_assignment *a, *n;
671 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
672 if (a->valid_until < now) {
673 if ((a->length < 128 && a->clid_len > 0) ||
674 (a->length == 128 && a->clid_len == 0)) {
675 list_del(&a->head);
676 free_dhcpv6_assignment(a);
677 }
678 } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
679 now > a->reconf_sent + (1 << a->reconf_cnt)) {
680 ++a->reconf_cnt;
681 a->reconf_sent = now;
682 send_reconf(iface, a);
683 }
684 }
685 }
686 uloop_timeout_set(event, 2000);
687 }
688
689
690 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
691 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
692 struct interface *iface, bool request)
693 {
694 if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
695 return 0;
696
697 struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
698 size_t datalen = sizeof(out);
699 time_t now = odhcpd_time();
700
701 if (status) {
702 struct __attribute__((packed)) {
703 uint16_t type;
704 uint16_t len;
705 uint16_t value;
706 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
707 htons(status)};
708
709 memcpy(buf + datalen, &stat, sizeof(stat));
710 datalen += sizeof(stat);
711 } else {
712 if (a) {
713 uint32_t leasetime = iface->dhcpv4_leasetime;
714 if (leasetime == 0)
715 leasetime = 3600;
716 else if (leasetime < 60)
717 leasetime = 60;
718
719 uint32_t pref = leasetime;
720 uint32_t valid = leasetime;
721
722 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
723 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
724 size_t m = 0;
725
726 for (size_t i = 0; i < addrlen; ++i)
727 if (addrs[i].preferred > addrs[m].preferred ||
728 (addrs[i].preferred == addrs[m].preferred &&
729 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
730 m = i;
731
732 for (size_t i = 0; i < addrlen; ++i) {
733 uint32_t prefix_pref = addrs[i].preferred;
734 uint32_t prefix_valid = addrs[i].valid;
735
736 if (addrs[i].prefix > 96 ||
737 addrs[i].preferred <= (uint32_t)now)
738 continue;
739
740 if (prefix_pref != UINT32_MAX)
741 prefix_pref -= now;
742
743 if (prefix_valid != UINT32_MAX)
744 prefix_valid -= now;
745
746 if (a->length < 128) {
747 struct dhcpv6_ia_prefix p = {
748 .type = htons(DHCPV6_OPT_IA_PREFIX),
749 .len = htons(sizeof(p) - 4),
750 .preferred = htonl(prefix_pref),
751 .valid = htonl(prefix_valid),
752 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
753 .addr = addrs[i].addr
754 };
755 p.addr.s6_addr32[1] |= htonl(a->assigned);
756
757 size_t entrlen = sizeof(p) - 4;
758
759 if (datalen + entrlen + 4 > buflen ||
760 (a->assigned == 0 && a->managed_size == 0) ||
761 (!a->managed_size && a->length < p.preferred))
762 continue;
763
764 memcpy(buf + datalen, &p, sizeof(p));
765 datalen += entrlen + 4;
766 } else {
767 struct dhcpv6_ia_addr n = {
768 .type = htons(DHCPV6_OPT_IA_ADDR),
769 .len = htons(sizeof(n) - 4),
770 .addr = addrs[i].addr,
771 .preferred = htonl(prefix_pref),
772 .valid = htonl(prefix_valid)
773 };
774 n.addr.s6_addr32[3] = htonl(a->assigned);
775 size_t entrlen = sizeof(n) - 4;
776
777 if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
778 addrs[i].prefix == 64)
779 continue;
780
781 if (datalen + entrlen + 4 > buflen || a->assigned == 0)
782 continue;
783
784 memcpy(buf + datalen, &n, sizeof(n));
785 datalen += entrlen + 4;
786 }
787
788 // Calculate T1 / T2 based on non-deprecated addresses
789 if (prefix_pref > 0) {
790 if (prefix_pref < pref)
791 pref = prefix_pref;
792
793 if (prefix_valid < valid)
794 valid = prefix_valid;
795 }
796 }
797
798 a->valid_until = valid + now;
799 out.t1 = htonl(pref * 5 / 10);
800 out.t2 = htonl(pref * 8 / 10);
801
802 if (!out.t1)
803 out.t1 = htonl(1);
804
805 if (!out.t2)
806 out.t2 = htonl(1);
807 }
808
809 if (!request) {
810 uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
811 uint16_t otype, olen;
812 dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
813 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
814 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
815 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
816 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
817 continue;
818
819 bool found = false;
820 if (a) {
821 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
822 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
823
824 for (size_t i = 0; i < addrlen; ++i) {
825 if (addrs[i].prefix > 96 ||
826 addrs[i].preferred <= (uint32_t)now)
827 continue;
828
829 struct in6_addr addr = addrs[i].addr;
830 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
831 addr.s6_addr32[1] |= htonl(a->assigned);
832
833 if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
834 p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
835 found = true;
836 } else {
837 addr.s6_addr32[3] = htonl(a->assigned);
838
839 if (!memcmp(&n->addr, &addr, sizeof(addr)))
840 found = true;
841 }
842 }
843 }
844
845 if (!found) {
846 if (otype == DHCPV6_OPT_IA_PREFIX) {
847 struct dhcpv6_ia_prefix inv = {
848 .type = htons(DHCPV6_OPT_IA_PREFIX),
849 .len = htons(sizeof(inv) - 4),
850 .preferred = 0,
851 .valid = 0,
852 .prefix = p->prefix,
853 .addr = p->addr
854 };
855
856 if (datalen + sizeof(inv) > buflen)
857 continue;
858
859 memcpy(buf + datalen, &inv, sizeof(inv));
860 datalen += sizeof(inv);
861 } else {
862 struct dhcpv6_ia_addr inv = {
863 .type = htons(DHCPV6_OPT_IA_ADDR),
864 .len = htons(sizeof(inv) - 4),
865 .addr = n->addr,
866 .preferred = 0,
867 .valid = 0
868 };
869
870 if (datalen + sizeof(inv) > buflen)
871 continue;
872
873 memcpy(buf + datalen, &inv, sizeof(inv));
874 datalen += sizeof(inv);
875 }
876 }
877 }
878 }
879 }
880
881 out.len = htons(datalen - 4);
882 memcpy(buf, &out, sizeof(out));
883 return datalen;
884 }
885
886
887 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
888 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
889 {
890 const char *type = "UNKNOWN";
891 const char *status = "UNKNOWN";
892
893 if (msgtype == DHCPV6_MSG_RENEW)
894 return;
895
896 switch (msgtype) {
897 case DHCPV6_MSG_SOLICIT:
898 type = "SOLICIT";
899 break;
900 case DHCPV6_MSG_REQUEST:
901 type = "REQUEST";
902 break;
903 case DHCPV6_MSG_CONFIRM:
904 type = "CONFIRM";
905 break;
906 case DHCPV6_MSG_RENEW:
907 type = "RENEW";
908 break;
909 case DHCPV6_MSG_REBIND:
910 type = "REBIND";
911 break;
912 case DHCPV6_MSG_RELEASE:
913 type = "RELEASE";
914 break;
915 case DHCPV6_MSG_DECLINE:
916 type = "DECLINE";
917 break;
918 }
919
920 switch (code) {
921 case DHCPV6_STATUS_OK:
922 status = "ok";
923 break;
924 case DHCPV6_STATUS_NOADDRSAVAIL:
925 status = "no addresses available";
926 break;
927 case DHCPV6_STATUS_NOBINDING:
928 status = "no binding";
929 break;
930 case DHCPV6_STATUS_NOTONLINK:
931 status = "not on-link";
932 break;
933 case DHCPV6_STATUS_NOPREFIXAVAIL:
934 status = "no prefix available";
935 break;
936 }
937
938 char leasebuf[256] = "";
939
940 if (a) {
941 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
942 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
943 size_t lbsize = 0;
944 char addrbuf[INET6_ADDRSTRLEN];
945
946 for (size_t i = 0; i < addrlen; ++i) {
947 if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
948 continue;
949
950 struct in6_addr addr = addrs[i].addr;
951 int prefix = a->managed ? addrs[i].prefix : a->length;
952 if (prefix == 128)
953 addr.s6_addr32[3] = htonl(a->assigned);
954 else
955 addr.s6_addr32[1] |= htonl(a->assigned);
956
957 inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
958 lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
959 }
960 }
961
962 syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
963 duidbuf, iface->ifname, status, leasebuf);
964 }
965
966
967
968 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
969 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
970 {
971 time_t now = odhcpd_time();
972 size_t response_len = 0;
973 const struct dhcpv6_client_header *hdr = data;
974 uint8_t *start = (uint8_t*)&hdr[1], *odata;
975 uint16_t otype, olen;
976
977 // Find and parse client-id and hostname
978 bool accept_reconf = false;
979 uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
980 char hostname[256];
981 size_t hostname_len = 0;
982 bool notonlink = false;
983 char duidbuf[261];
984
985 dhcpv6_for_each_option(start, end, otype, olen, odata) {
986 if (otype == DHCPV6_OPT_CLIENTID) {
987 clid_data = odata;
988 clid_len = olen;
989
990 if (olen == 14 && odata[0] == 0 && odata[1] == 1)
991 memcpy(mac, &odata[8], sizeof(mac));
992 else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
993 memcpy(mac, &odata[4], sizeof(mac));
994
995 if (olen <= 130)
996 odhcpd_hexlify(duidbuf, odata, olen);
997 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
998 uint8_t fqdn_buf[256];
999 memcpy(fqdn_buf, odata, olen);
1000 fqdn_buf[olen++] = 0;
1001
1002 if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
1003 hostname_len = strcspn(hostname, ".");
1004 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
1005 accept_reconf = true;
1006 }
1007 }
1008
1009 if (!clid_data || !clid_len || clid_len > 130)
1010 goto out;
1011
1012 update(iface);
1013
1014 struct dhcpv6_assignment *first = NULL;
1015 dhcpv6_for_each_option(start, end, otype, olen, odata) {
1016 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1017 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1018 bool ia_addr_present = false;
1019 if (!is_pd && !is_na)
1020 continue;
1021
1022 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1023 size_t ia_response_len = 0;
1024 uint8_t reqlen = (is_pd) ? 62 : 128;
1025 uint32_t reqhint = 0;
1026
1027 // Parse request hint for IA-PD
1028 if (is_pd) {
1029 uint8_t *sdata;
1030 uint16_t stype, slen;
1031 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1032 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1033 continue;
1034
1035 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1036 if (p->prefix) {
1037 reqlen = p->prefix;
1038 reqhint = ntohl(p->addr.s6_addr32[1]);
1039 if (reqlen > 32 && reqlen <= 64)
1040 reqhint &= (1U << (64 - reqlen)) - 1;
1041 }
1042 }
1043
1044 if (reqlen > 64)
1045 reqlen = 64;
1046 } else if (is_na) {
1047 uint8_t *sdata;
1048 uint16_t stype, slen;
1049 dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1050 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1051 continue;
1052
1053 ia_addr_present = true;
1054 }
1055 }
1056
1057 // Find assignment
1058 struct dhcpv6_assignment *c, *a = NULL;
1059 list_for_each_entry(c, &iface->ia_assignments, head) {
1060 if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1061 (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1062 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1063 (c->iaid == ia->iaid || c->valid_until < now) &&
1064 ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1065 a = c;
1066
1067 // Reset state
1068 apply_lease(iface, a, false);
1069 memcpy(a->clid_data, clid_data, clid_len);
1070 a->clid_len = clid_len;
1071 a->iaid = ia->iaid;
1072 a->peer = *addr;
1073 a->reconf_cnt = 0;
1074 a->reconf_sent = 0;
1075 break;
1076 }
1077 }
1078
1079 // Generic message handling
1080 uint16_t status = DHCPV6_STATUS_OK;
1081 if (a && a->managed_size < 0) {
1082 return -1;
1083 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1084 bool assigned = !!a;
1085
1086 if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1087 a = calloc(1, sizeof(*a) + clid_len);
1088 if (a) {
1089 a->clid_len = clid_len;
1090 a->iaid = ia->iaid;
1091 a->length = reqlen;
1092 a->peer = *addr;
1093 a->assigned = reqhint;
1094
1095 if (first)
1096 memcpy(a->key, first->key, sizeof(a->key));
1097 else
1098 odhcpd_urandom(a->key, sizeof(a->key));
1099 memcpy(a->clid_data, clid_data, clid_len);
1100
1101 if (is_pd)
1102 while (!(assigned = assign_pd(iface, a)) &&
1103 !a->managed_size && ++a->length <= 64);
1104 else
1105 assigned = assign_na(iface, a);
1106
1107 if (a->managed_size && !assigned)
1108 return -1;
1109 }
1110 }
1111
1112 if (!assigned || iface->ia_addr_len == 0) { // Set error status
1113 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1114 } else if (assigned && !first) { //
1115 size_t handshake_len = 4;
1116 buf[0] = 0;
1117 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1118 buf[2] = 0;
1119 buf[3] = 0;
1120
1121 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1122 struct dhcpv6_auth_reconfigure auth = {
1123 htons(DHCPV6_OPT_AUTH),
1124 htons(sizeof(auth) - 4),
1125 3, 1, 0,
1126 {htonl(time(NULL)), htonl(++serial)},
1127 1,
1128 {0}
1129 };
1130 memcpy(auth.key, a->key, sizeof(a->key));
1131 memcpy(buf + handshake_len, &auth, sizeof(auth));
1132 handshake_len += sizeof(auth);
1133 }
1134
1135 buf += handshake_len;
1136 buflen -= handshake_len;
1137 response_len += handshake_len;
1138
1139 first = a;
1140 }
1141
1142 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1143
1144 // Was only a solicitation: mark binding for removal
1145 if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1146 a->valid_until = 0;
1147 } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1148 if (hostname_len > 0) {
1149 a->hostname = realloc(a->hostname, hostname_len + 1);
1150 if (a->hostname) {
1151 memcpy(a->hostname, hostname, hostname_len);
1152 a->hostname[hostname_len] = 0;
1153 }
1154 }
1155 a->accept_reconf = accept_reconf;
1156 apply_lease(iface, a, true);
1157 } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1158 free_dhcpv6_assignment(a);
1159 }
1160 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1161 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1162 hdr->msg_type == DHCPV6_MSG_REBIND ||
1163 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1164 if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1165 status = DHCPV6_STATUS_NOBINDING;
1166 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1167 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1168 hdr->msg_type == DHCPV6_MSG_REBIND) {
1169 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1170 if (a)
1171 apply_lease(iface, a, true);
1172 } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1173 a->valid_until = 0;
1174 apply_lease(iface, a, false);
1175 } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1176 a->clid_len = 0;
1177 a->valid_until = now + 3600; // Block address for 1h
1178 }
1179 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1180 // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1181 status = DHCPV6_STATUS_NOTONLINK;
1182 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1183 notonlink = true;
1184 }
1185
1186 buf += ia_response_len;
1187 buflen -= ia_response_len;
1188 response_len += ia_response_len;
1189 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1190 }
1191
1192 if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1193 response_len + 6 < buflen) {
1194 buf[0] = 0;
1195 buf[1] = DHCPV6_OPT_STATUS;
1196 buf[2] = 0;
1197 buf[3] = 2;
1198 buf[4] = 0;
1199 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1200 response_len += 6;
1201 }
1202
1203 dhcpv6_write_statefile();
1204
1205 out:
1206 return response_len;
1207 }
OpenWrt DHCP Server