Revert "Respect interface "ignore" settings as documented."
[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->flags & OAF_BOUND) || 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                                         if (!(c->flags & OAF_BOUND))
306                                                 continue;
307
308                                         char ipbuf[INET6_ADDRSTRLEN];
309                                         char leasebuf[512];
310                                         char duidbuf[16];
311                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
312
313                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
314                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
315                                                         iface->ifname, duidbuf,
316                                                         (c->hostname ? c->hostname : "-"),
317                                                         (c->valid_until > now ?
318                                                                 (c->valid_until - now + wall_time) :
319                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
320                                                         c->addr);
321
322                                         struct in_addr addr = {htonl(c->addr)};
323                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
324
325                                         if (c->hostname[0]) {
326                                                 fputs(ipbuf, fp);
327
328                                                 char b[256];
329                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
330                                                                 iface->search, b, sizeof(b)) > 0)
331                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
332
333                                                 fprintf(fp, "\t%s\n", c->hostname);
334                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
335                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
336                                         }
337
338                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
339                                         leasebuf[l - 1] = '\n';
340                                         fwrite(leasebuf, 1, l, fp);
341                                 }
342                         }
343                 }
344
345                 fclose(fp);
346         }
347
348         uint8_t newmd5[16];
349         md5_end(newmd5, &md5);
350
351         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
352                 memcpy(statemd5, newmd5, sizeof(statemd5));
353                 char *argv[2] = {config.dhcp_cb, NULL};
354                 if (!vfork()) {
355                         execv(argv[0], argv);
356                         _exit(128);
357                 }
358         }
359 }
360
361
362 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
363 {
364         if (a->length > 64 || a->managed_size < 0)
365                 return;
366
367         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
368         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
369
370         for (size_t i = 0; i < addrlen; ++i) {
371                 struct in6_addr prefix = addrs[i].addr;
372                 prefix.s6_addr32[1] |= htonl(a->assigned);
373                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
374                                 iface, &a->peer.sin6_addr, 1024, add);
375         }
376 }
377
378
379 // More data was received from TCP connection
380 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
381 {
382         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
383         time_t now = odhcpd_time();
384         bool first = c->managed_size < 0;
385
386         for (;;) {
387                 int pending;
388                 char *data = ustream_get_read_buf(s, &pending);
389                 char *end = memmem(data, pending, "\n\n", 2);
390
391                 if (!end)
392                         break;
393
394                 end += 2;
395                 end[-1] = 0;
396
397                 c->managed_size = 0;
398                 if (c->accept_reconf)
399                         c->reconf_cnt = 1;
400
401                 char *saveptr;
402                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
403                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
404                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
405
406                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
407                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
408                                 continue;
409
410                         x = strtok_r(NULL, ",", &saveptr2);
411                         if (sscanf(x, "%hhu", &n->prefix) < 1)
412                                 continue;
413
414                         x = strtok_r(NULL, ",", &saveptr2);
415                         if (sscanf(x, "%u", &n->preferred) < 1)
416                                 continue;
417
418                         x = strtok_r(NULL, ",", &saveptr2);
419                         if (sscanf(x, "%u", &n->valid) < 1)
420                                 continue;
421
422                         if (n->preferred > n->valid)
423                                 continue;
424
425                         if (UINT32_MAX - now < n->preferred)
426                                 n->preferred = UINT32_MAX;
427                         else
428                                 n->preferred += now;
429
430                         if (UINT32_MAX - now < n->valid)
431                                 n->valid = UINT32_MAX;
432                         else
433                                 n->valid += now;
434
435                         n->dprefix = 0;
436
437                         ++c->managed_size;
438                 }
439
440                 ustream_consume(s, end - data);
441         }
442
443         if (first && c->managed_size == 0)
444                 free_dhcpv6_assignment(c);
445         else if (first)
446                 c->valid_until = now + 150;
447 }
448
449
450 // TCP transmission has ended, either because of success or timeout or other error
451 static void managed_handle_pd_done(struct ustream *s)
452 {
453         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
454         c->valid_until = odhcpd_time() + 15;
455         c->managed_size = 0;
456         if (c->accept_reconf)
457                 c->reconf_cnt = 1;
458 }
459
460
461
462 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
463 {
464         struct dhcpv6_assignment *c;
465
466         if (iface->dhcpv6_pd_manager[0]) {
467                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
468                 if (fd >= 0) {
469                         char iaidbuf[298];
470                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
471
472                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
473                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
474                         ustream_fd_init(&assign->managed_sock, fd);
475                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
476                                         iaidbuf, assign->iaid, assign->length);
477                         ustream_write_pending(&assign->managed_sock.stream);
478                         assign->managed_size = -1;
479                         assign->valid_until = odhcpd_time() + 15;
480                         list_add(&assign->head, &iface->ia_assignments);
481
482                         // Wait initial period of up to 250ms for immediate assignment
483                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
484                         poll(&pfd, 1, 250);
485                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
486
487                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
488                                 return true;
489                 }
490
491                 return false;
492         } else if (iface->ia_addr_len < 1) {
493                 return false;
494         }
495
496         // Try honoring the hint first
497         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
498         if (assign->assigned) {
499                 list_for_each_entry(c, &iface->ia_assignments, head) {
500                         if (c->length == 128 || c->length == 0)
501                                 continue;
502
503                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
504                                 list_add_tail(&assign->head, &c->head);
505                                 apply_lease(iface, assign, true);
506                                 return true;
507                         }
508
509                         if (c->assigned != 0)
510                                 current = (c->assigned + (1 << (64 - c->length)));
511                 }
512         }
513
514         // Fallback to a variable assignment
515         current = 1;
516         list_for_each_entry(c, &iface->ia_assignments, head) {
517                 if (c->length == 128 || c->length == 0)
518                         continue;
519
520                 current = (current + asize) & (~asize);
521                 if (current + asize < c->assigned) {
522                         assign->assigned = current;
523                         list_add_tail(&assign->head, &c->head);
524                         apply_lease(iface, assign, true);
525                         return true;
526                 }
527
528                 if (c->assigned != 0)
529                         current = (c->assigned + (1 << (64 - c->length)));
530         }
531
532         return false;
533 }
534
535
536 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
537 {
538         // Seed RNG with checksum of DUID
539         uint32_t seed = 0;
540         for (size_t i = 0; i < assign->clid_len; ++i)
541                 seed += assign->clid_data[i];
542         srand(seed);
543
544         // Try to assign up to 100x
545         for (size_t i = 0; i < 100; ++i) {
546                 uint32_t try;
547                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
548
549                 struct dhcpv6_assignment *c;
550                 list_for_each_entry(c, &iface->ia_assignments, head) {
551                         if (c->length == 0)
552                                 continue;
553
554                         if (c->assigned > try || c->length != 128) {
555                                 assign->assigned = try;
556                                 list_add_tail(&assign->head, &c->head);
557                                 return true;
558                         } else if (c->assigned == try) {
559                                 break;
560                         }
561                 }
562         }
563
564         return false;
565 }
566
567 void dhcpv6_ia_preupdate(struct interface *iface)
568 {
569         if (iface->dhcpv6 != RELAYD_SERVER)
570                 return;
571
572         struct dhcpv6_assignment *c, *border = list_last_entry(
573                         &iface->ia_assignments, struct dhcpv6_assignment, head);
574         list_for_each_entry(c, &iface->ia_assignments, head)
575                 if (c != border && !iface->managed)
576                         apply_lease(iface, c, false);
577 }
578
579 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
580 {
581         if (iface->dhcpv6 != RELAYD_SERVER)
582                 return;
583
584         int minprefix = -1;
585         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
586                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
587                                 iface->ia_addr[i].prefix < 64 &&
588                                 iface->ia_addr[i].prefix > minprefix)
589                         minprefix = iface->ia_addr[i].prefix;
590         }
591
592         struct dhcpv6_assignment *border = list_last_entry(
593                         &iface->ia_assignments, struct dhcpv6_assignment, head);
594         if (minprefix > 32 && minprefix <= 64)
595                 border->assigned = 1U << (64 - minprefix);
596         else
597                 border->assigned = 0;
598
599         struct list_head reassign = LIST_HEAD_INIT(reassign);
600         struct dhcpv6_assignment *c, *d;
601         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
602                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
603                                 c->managed_size)
604                         continue;
605
606                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
607                         list_move(&c->head, &reassign);
608                 else if (c != border)
609                         apply_lease(iface, c, true);
610
611                 if (c->accept_reconf && c->reconf_cnt == 0) {
612                         c->reconf_cnt = 1;
613                         c->reconf_sent = now;
614                         send_reconf(iface, c);
615
616                         // Leave all other assignments of that client alone
617                         struct dhcpv6_assignment *a;
618                         list_for_each_entry(a, &iface->ia_assignments, head)
619                                 if (a != c && a->clid_len == c->clid_len &&
620                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
621                                         c->reconf_cnt = INT_MAX;
622                 }
623         }
624
625         while (!list_empty(&reassign)) {
626                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
627                 list_del(&c->head);
628                 if (!assign_pd(iface, c)) {
629                         c->assigned = 0;
630                         list_add(&c->head, &iface->ia_assignments);
631                 }
632         }
633
634         dhcpv6_write_statefile();
635 }
636
637
638 static void reconf_timer(struct uloop_timeout *event)
639 {
640         time_t now = odhcpd_time();
641         struct interface *iface;
642         list_for_each_entry(iface, &interfaces, head) {
643                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
644                         continue;
645
646                 struct dhcpv6_assignment *a, *n;
647                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
648                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
649                                 if ((a->length < 128 && a->clid_len > 0) ||
650                                                 (a->length == 128 && a->clid_len == 0)) {
651                                         list_del(&a->head);
652                                         free_dhcpv6_assignment(a);
653                                 }
654                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
655                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
656                                 ++a->reconf_cnt;
657                                 a->reconf_sent = now;
658                                 send_reconf(iface, a);
659                         }
660                 }
661         }
662         uloop_timeout_set(event, 2000);
663 }
664
665
666 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
667                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
668                 struct interface *iface, bool request)
669 {
670         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
671                 return 0;
672
673         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
674         size_t datalen = sizeof(out);
675         time_t now = odhcpd_time();
676
677         if (status) {
678                 struct __attribute__((packed)) {
679                         uint16_t type;
680                         uint16_t len;
681                         uint16_t value;
682                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
683                                 htons(status)};
684
685                 memcpy(buf + datalen, &stat, sizeof(stat));
686                 datalen += sizeof(stat);
687         } else {
688                 if (a) {
689                         uint32_t leasetime;
690                         if (a->leasetime > 0) {
691                                 leasetime = a->leasetime;
692                         } else {
693                                 leasetime = iface->dhcpv4_leasetime;
694                         }
695                         if (leasetime == 0)
696                                 leasetime = 3600;
697                         else if (leasetime < 60)
698                                 leasetime = 60;
699
700                         uint32_t pref = leasetime;
701                         uint32_t valid = leasetime;
702
703                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
704                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
705                         size_t m = 0;
706
707                         for (size_t i = 0; i < addrlen; ++i)
708                                 if (addrs[i].preferred > addrs[m].preferred ||
709                                                 (addrs[i].preferred == addrs[m].preferred &&
710                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
711                                         m = i;
712
713                         for (size_t i = 0; i < addrlen; ++i) {
714                                 uint32_t prefix_pref = addrs[i].preferred;
715                                 uint32_t prefix_valid = addrs[i].valid;
716
717                                 if (addrs[i].prefix > 96 ||
718                                                 addrs[i].preferred <= (uint32_t)now)
719                                         continue;
720
721                                 if (prefix_pref != UINT32_MAX)
722                                         prefix_pref -= now;
723
724                                 if (prefix_valid != UINT32_MAX)
725                                         prefix_valid -= now;
726
727                                 if (a->length < 128) {
728                                         struct dhcpv6_ia_prefix p = {
729                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
730                                                 .len = htons(sizeof(p) - 4),
731                                                 .preferred = htonl(prefix_pref),
732                                                 .valid = htonl(prefix_valid),
733                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
734                                                 .addr = addrs[i].addr
735                                         };
736                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
737
738                                         size_t entrlen = sizeof(p) - 4;
739
740                                         if (datalen + entrlen + 4 > buflen ||
741                                                         (a->assigned == 0 && a->managed_size == 0) ||
742                                                         (!a->managed_size && a->length <= addrs[i].prefix))
743                                                 continue;
744
745                                         memcpy(buf + datalen, &p, sizeof(p));
746                                         datalen += entrlen + 4;
747                                 } else {
748                                         struct dhcpv6_ia_addr n = {
749                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
750                                                 .len = htons(sizeof(n) - 4),
751                                                 .addr = addrs[i].addr,
752                                                 .preferred = htonl(prefix_pref),
753                                                 .valid = htonl(prefix_valid)
754                                         };
755                                         n.addr.s6_addr32[3] = htonl(a->assigned);
756                                         size_t entrlen = sizeof(n) - 4;
757
758                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
759                                                         addrs[i].prefix <= 64)
760                                                 continue;
761
762                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
763                                                 continue;
764
765                                         memcpy(buf + datalen, &n, sizeof(n));
766                                         datalen += entrlen + 4;
767                                 }
768
769                                 // Calculate T1 / T2 based on non-deprecated addresses
770                                 if (prefix_pref > 0) {
771                                         if (prefix_pref < pref)
772                                                 pref = prefix_pref;
773
774                                         if (prefix_valid < valid)
775                                                 valid = prefix_valid;
776                                 }
777                         }
778
779                         if (!INFINITE_VALID(a->valid_until))
780                                 /* UINT32_MAX is considered as infinite leasetime */
781                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
782
783                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
784                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
785
786                         if (!out.t1)
787                                 out.t1 = htonl(1);
788
789                         if (!out.t2)
790                                 out.t2 = htonl(1);
791                 }
792
793                 if (!request) {
794                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
795                         uint16_t otype, olen;
796                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
797                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
798                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
799                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
800                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
801                                         continue;
802
803                                 bool found = false;
804                                 if (a) {
805                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
806                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
807
808                                         for (size_t i = 0; i < addrlen; ++i) {
809                                                 if (addrs[i].prefix > 96 ||
810                                                                 addrs[i].preferred <= (uint32_t)now)
811                                                         continue;
812
813                                                 struct in6_addr addr = addrs[i].addr;
814                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
815                                                         addr.s6_addr32[1] |= htonl(a->assigned);
816
817                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
818                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
819                                                                 found = true;
820                                                 } else {
821                                                         addr.s6_addr32[3] = htonl(a->assigned);
822
823                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
824                                                                 found = true;
825                                                 }
826                                         }
827                                 }
828
829                                 if (!found) {
830                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
831                                                 struct dhcpv6_ia_prefix inv = {
832                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
833                                                         .len = htons(sizeof(inv) - 4),
834                                                         .preferred = 0,
835                                                         .valid = 0,
836                                                         .prefix = p->prefix,
837                                                         .addr = p->addr
838                                                 };
839
840                                                 if (datalen + sizeof(inv) > buflen)
841                                                         continue;
842
843                                                 memcpy(buf + datalen, &inv, sizeof(inv));
844                                                 datalen += sizeof(inv);
845                                         } else {
846                                                 struct dhcpv6_ia_addr inv = {
847                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
848                                                         .len = htons(sizeof(inv) - 4),
849                                                         .addr = n->addr,
850                                                         .preferred = 0,
851                                                         .valid = 0
852                                                 };
853
854                                                 if (datalen + sizeof(inv) > buflen)
855                                                         continue;
856
857                                                 memcpy(buf + datalen, &inv, sizeof(inv));
858                                                 datalen += sizeof(inv);
859                                         }
860                                 }
861                         }
862                 }
863         }
864
865         out.len = htons(datalen - 4);
866         memcpy(buf, &out, sizeof(out));
867         return datalen;
868 }
869
870
871 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
872                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
873 {
874         const char *type = "UNKNOWN";
875         const char *status = "UNKNOWN";
876
877         if (msgtype == DHCPV6_MSG_RENEW)
878                 return;
879
880         switch (msgtype) {
881         case DHCPV6_MSG_SOLICIT:
882                 type = "SOLICIT";
883                 break;
884         case DHCPV6_MSG_REQUEST:
885                 type = "REQUEST";
886                 break;
887         case DHCPV6_MSG_CONFIRM:
888                 type = "CONFIRM";
889                 break;
890         case DHCPV6_MSG_RENEW:
891                 type = "RENEW";
892                 break;
893         case DHCPV6_MSG_REBIND:
894                 type = "REBIND";
895                 break;
896         case DHCPV6_MSG_RELEASE:
897                 type = "RELEASE";
898                 break;
899         case DHCPV6_MSG_DECLINE:
900                 type = "DECLINE";
901                 break;
902         }
903
904         switch (code) {
905         case DHCPV6_STATUS_OK:
906                 status = "ok";
907                 break;
908         case DHCPV6_STATUS_NOADDRSAVAIL:
909                 status = "no addresses available";
910                 break;
911         case DHCPV6_STATUS_NOBINDING:
912                 status = "no binding";
913                 break;
914         case DHCPV6_STATUS_NOTONLINK:
915                 status = "not on-link";
916                 break;
917         case DHCPV6_STATUS_NOPREFIXAVAIL:
918                 status = "no prefix available";
919                 break;
920         }
921
922         char leasebuf[256] = "";
923
924         if (a) {
925                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
926                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
927                 size_t lbsize = 0;
928                 char addrbuf[INET6_ADDRSTRLEN];
929
930                 for (size_t i = 0; i < addrlen; ++i) {
931                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
932                                 continue;
933
934                         struct in6_addr addr = addrs[i].addr;
935                         int prefix = a->managed ? addrs[i].prefix : a->length;
936                         if (prefix == 128)
937                                 addr.s6_addr32[3] = htonl(a->assigned);
938                         else
939                                 addr.s6_addr32[1] |= htonl(a->assigned);
940
941                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
942                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
943                 }
944         }
945
946         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
947                         duidbuf, iface->ifname, status, leasebuf);
948 }
949
950
951
952 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
953                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
954 {
955         time_t now = odhcpd_time();
956         size_t response_len = 0;
957         const struct dhcpv6_client_header *hdr = data;
958         uint8_t *start = (uint8_t*)&hdr[1], *odata;
959         uint16_t otype, olen;
960
961         // Find and parse client-id and hostname
962         bool accept_reconf = false;
963         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
964         char hostname[256];
965         size_t hostname_len = 0;
966         bool notonlink = false;
967         char duidbuf[261];
968
969         dhcpv6_for_each_option(start, end, otype, olen, odata) {
970                 if (otype == DHCPV6_OPT_CLIENTID) {
971                         clid_data = odata;
972                         clid_len = olen;
973
974                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
975                                 memcpy(mac, &odata[8], sizeof(mac));
976                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
977                                 memcpy(mac, &odata[4], sizeof(mac));
978
979                         if (olen <= 130)
980                                 odhcpd_hexlify(duidbuf, odata, olen);
981                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
982                         uint8_t fqdn_buf[256];
983                         memcpy(fqdn_buf, odata, olen);
984                         fqdn_buf[olen++] = 0;
985
986                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
987                                 hostname_len = strcspn(hostname, ".");
988                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
989                         accept_reconf = true;
990                 }
991         }
992
993         if (!clid_data || !clid_len || clid_len > 130)
994                 goto out;
995
996         struct dhcpv6_assignment *first = NULL;
997         dhcpv6_for_each_option(start, end, otype, olen, odata) {
998                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
999                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1000                 bool ia_addr_present = false;
1001                 if (!is_pd && !is_na)
1002                         continue;
1003
1004                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1005                 size_t ia_response_len = 0;
1006                 uint8_t reqlen = (is_pd) ? 62 : 128;
1007                 uint32_t reqhint = 0;
1008
1009                 // Parse request hint for IA-PD
1010                 if (is_pd) {
1011                         uint8_t *sdata;
1012                         uint16_t stype, slen;
1013                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1014                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1015                                         continue;
1016
1017                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1018                                 if (p->prefix) {
1019                                         reqlen = p->prefix;
1020                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1021                                         if (reqlen > 32 && reqlen <= 64)
1022                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1023                                 }
1024                         }
1025
1026                         if (reqlen > 64)
1027                                 reqlen = 64;
1028                 } else if (is_na) {
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_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1033                                         continue;
1034
1035                                 ia_addr_present = true;
1036                         }
1037                 }
1038
1039                 // Find assignment
1040                 struct dhcpv6_assignment *c, *a = NULL;
1041                 list_for_each_entry(c, &iface->ia_assignments, head) {
1042                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1043                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1044                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1045                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1046                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1047                                 a = c;
1048
1049                                 // Reset state
1050                                 apply_lease(iface, a, false);
1051                                 memcpy(a->clid_data, clid_data, clid_len);
1052                                 a->clid_len = clid_len;
1053                                 a->iaid = ia->iaid;
1054                                 a->peer = *addr;
1055                                 a->reconf_cnt = 0;
1056                                 a->reconf_sent = 0;
1057                                 break;
1058                         }
1059                 }
1060
1061                 // Generic message handling
1062                 uint16_t status = DHCPV6_STATUS_OK;
1063                 if (a && a->managed_size < 0) {
1064                         return -1;
1065                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1066                         bool assigned = !!a;
1067
1068                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1069                                 a = calloc(1, sizeof(*a) + clid_len);
1070                                 if (a) {
1071                                         a->clid_len = clid_len;
1072                                         a->iaid = ia->iaid;
1073                                         a->length = reqlen;
1074                                         a->peer = *addr;
1075                                         a->assigned = reqhint;
1076                                         // Set valid time to current time indicating
1077                                         // assignment is not having infinite lifetime
1078                                         a->valid_until = now;
1079
1080                                         if (first)
1081                                                 memcpy(a->key, first->key, sizeof(a->key));
1082                                         else
1083                                                 odhcpd_urandom(a->key, sizeof(a->key));
1084                                         memcpy(a->clid_data, clid_data, clid_len);
1085
1086                                         if (is_pd)
1087                                                 while (!(assigned = assign_pd(iface, a)) &&
1088                                                                 !a->managed_size && ++a->length <= 64);
1089                                         else
1090                                                 assigned = assign_na(iface, a);
1091
1092                                         if (a->managed_size && !assigned)
1093                                                 return -1;
1094                                 }
1095                         }
1096
1097                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1098                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1099                         } else if (assigned && !first) { //
1100                                 size_t handshake_len = 4;
1101                                 buf[0] = 0;
1102                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1103                                 buf[2] = 0;
1104                                 buf[3] = 0;
1105
1106                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1107                                         struct dhcpv6_auth_reconfigure auth = {
1108                                                 htons(DHCPV6_OPT_AUTH),
1109                                                 htons(sizeof(auth) - 4),
1110                                                 3, 1, 0,
1111                                                 {htonl(time(NULL)), htonl(++serial)},
1112                                                 1,
1113                                                 {0}
1114                                         };
1115                                         memcpy(auth.key, a->key, sizeof(a->key));
1116                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1117                                         handshake_len += sizeof(auth);
1118                                 }
1119
1120                                 buf += handshake_len;
1121                                 buflen -= handshake_len;
1122                                 response_len += handshake_len;
1123
1124                                 first = a;
1125                         }
1126
1127                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1128
1129                         // Was only a solicitation: mark binding for removal
1130                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1131                                 a->flags &= ~OAF_BOUND;
1132
1133                                 if (!INFINITE_VALID(a->valid_until))
1134                                         a->valid_until = now;
1135                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1136                                 if (hostname_len > 0) {
1137                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1138                                         if (a->hostname) {
1139                                                 memcpy(a->hostname, hostname, hostname_len);
1140                                                 a->hostname[hostname_len] = 0;
1141                                         }
1142                                 }
1143                                 a->accept_reconf = accept_reconf;
1144                                 a->flags |= OAF_BOUND;
1145                                 apply_lease(iface, a, true);
1146                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1147                                 free_dhcpv6_assignment(a);
1148                         }
1149                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1150                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1151                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1152                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1153                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1154                                 status = DHCPV6_STATUS_NOBINDING;
1155                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1156                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1157                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1158                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1159                                 if (a) {
1160                                         a->flags |= OAF_BOUND;
1161                                         apply_lease(iface, a, true);
1162                                 }
1163                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1164                                 if (!INFINITE_VALID(a->valid_until))
1165                                         a->valid_until = now - 1;
1166
1167                                 a->flags &= ~OAF_BOUND;
1168                                 apply_lease(iface, a, false);
1169                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1170                                 a->flags &= ~OAF_BOUND;
1171
1172                                 if (!INFINITE_VALID(a->valid_until)) {
1173                                         a->clid_len = 0;
1174                                         a->valid_until = now + 3600; // Block address for 1h
1175                                 }
1176                         }
1177                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1178                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1179                         status = DHCPV6_STATUS_NOTONLINK;
1180                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1181                         notonlink = true;
1182                 }
1183
1184                 buf += ia_response_len;
1185                 buflen -= ia_response_len;
1186                 response_len += ia_response_len;
1187                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1188         }
1189
1190         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1191                         response_len + 6 < buflen) {
1192                 buf[0] = 0;
1193                 buf[1] = DHCPV6_OPT_STATUS;
1194                 buf[2] = 0;
1195                 buf[3] = 2;
1196                 buf[4] = 0;
1197                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1198                 response_len += 6;
1199         }
1200
1201         dhcpv6_write_statefile();
1202
1203 out:
1204         return response_len;
1205 }