router: support ra_mininterval and ra_lifetime uci parameters (FS#397)
[project/odhcpd.git] / src / dhcpv6-ia.c
1 /**
2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
3  * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License v2 as published by
7  * the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  */
15
16 #include "odhcpd.h"
17 #include "dhcpv6.h"
18 #include "dhcpv4.h"
19 #include "libubox/md5.h"
20 #include "libubox/usock.h"
21
22 #include <time.h>
23 #include <errno.h>
24 #include <fcntl.h>
25 #include <stdio.h>
26 #include <poll.h>
27 #include <alloca.h>
28 #include <resolv.h>
29 #include <limits.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <stdbool.h>
34 #include <arpa/inet.h>
35 #include <sys/timerfd.h>
36
37 #define ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) \
38     ((iface)->managed == RELAYD_MANAGED_NO_AFLAG || (i) == (m) || \
39      (addrs)[(i)].prefix > 64)
40
41 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
42 static void reconf_timer(struct uloop_timeout *event);
43 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
44 static uint32_t serial = 0;
45 static uint8_t statemd5[16];
46
47 int dhcpv6_ia_init(void)
48 {
49         uloop_timeout_set(&reconf_event, 2000);
50         return 0;
51 }
52
53 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
54 {
55         if (!enable && iface->ia_assignments.next) {
56                 struct dhcpv6_assignment *c;
57
58                 while (!list_empty(&iface->ia_assignments)) {
59                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
60                         free_dhcpv6_assignment(c);
61                 }
62         }
63
64         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
65                 if (!iface->ia_assignments.next)
66                         INIT_LIST_HEAD(&iface->ia_assignments);
67
68                 if (list_empty(&iface->ia_assignments)) {
69                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
70                         if (!border) {
71                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
72                                 return -1;
73                         }
74
75                         border->length = 64;
76                         list_add(&border->head, &iface->ia_assignments);
77                 }
78
79                 /* Parse static entries */
80                 struct lease *lease;
81                 list_for_each_entry(lease, &leases, head) {
82                         /* Construct entry */
83                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
84                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
85                         if (!a) {
86                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
87                                         iface->ifname);
88                                 return -1;
89                         }
90
91                         if (lease->dhcpv4_leasetime > 0)
92                                 a->leasetime = lease->dhcpv4_leasetime;
93
94                         a->clid_len = duid_len;
95                         a->length = 128;
96                         if (lease->hostid) {
97                                 a->assigned = lease->hostid;
98                         } else {
99                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
100                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
101                         }
102
103                         odhcpd_urandom(a->key, sizeof(a->key));
104                         memcpy(a->clid_data, lease->duid, lease->duid_len);
105                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
106                         /* Static assignment */
107                         a->flags |= OAF_STATIC;
108                         /* Infinite valid */
109                         a->valid_until = 0;
110
111                         /* Assign to all interfaces */
112                         struct dhcpv6_assignment *c;
113                         list_for_each_entry(c, &iface->ia_assignments, head) {
114                                 if (c->length != 128 || c->assigned > a->assigned) {
115                                         list_add_tail(&a->head, &c->head);
116                                         break;
117                                 } else if (c->assigned == a->assigned)
118                                         /* Already an assignment with that number */
119                                         break;
120                         }
121
122                         if (a->head.next) {
123                                 if (lease->hostname[0]) {
124                                         free(a->hostname);
125                                         a->hostname = strdup(lease->hostname);
126                                 }
127                         } else
128                                 free_dhcpv6_assignment(a);
129                 }
130         }
131         return 0;
132 }
133
134 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
135 {
136         if (c->managed_sock.fd.registered) {
137                 ustream_free(&c->managed_sock.stream);
138                 close(c->managed_sock.fd.fd);
139         }
140
141         if (c->head.next)
142                 list_del(&c->head);
143
144         free(c->managed);
145         free(c->hostname);
146         free(c);
147 }
148
149 static inline bool valid_prefix_length(const struct dhcpv6_assignment *a, const uint8_t prefix_length)
150 {
151         return (a->managed_size || a->length > prefix_length);
152 }
153
154 static inline bool valid_addr(const struct odhcpd_ipaddr *addr, time_t now)
155 {
156         return (addr->prefix <= 96 && addr->preferred > (uint32_t)now);
157 }
158
159 static size_t elect_addr(const struct odhcpd_ipaddr *addrs, const size_t addrlen)
160 {
161         size_t i, m;
162
163         for (i = 0, m = 0; i < addrlen; ++i) {
164                 if (addrs[i].preferred > addrs[m].preferred ||
165                         (addrs[i].preferred == addrs[m].preferred &&
166                          memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
167                         m = i;
168         }
169
170         return m;
171 }
172
173 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
174 {
175         struct {
176                 struct dhcpv6_client_header hdr;
177                 uint16_t srvid_type;
178                 uint16_t srvid_len;
179                 uint16_t duid_type;
180                 uint16_t hardware_type;
181                 uint8_t mac[6];
182                 uint16_t msg_type;
183                 uint16_t msg_len;
184                 uint8_t msg_id;
185                 struct dhcpv6_auth_reconfigure auth;
186                 uint16_t clid_type;
187                 uint16_t clid_len;
188                 uint8_t clid_data[128];
189         } __attribute__((packed)) reconf_msg = {
190                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
191                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
192                 .srvid_len = htons(10),
193                 .duid_type = htons(3),
194                 .hardware_type = htons(1),
195                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
196                 .msg_len = htons(1),
197                 .msg_id = DHCPV6_MSG_RENEW,
198                 .auth = {htons(DHCPV6_OPT_AUTH),
199                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
200                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
201                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
202                 .clid_len = htons(assign->clid_len),
203                 .clid_data = {0},
204         };
205
206         odhcpd_get_mac(iface, reconf_msg.mac);
207         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
208         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
209
210         md5_ctx_t md5;
211         uint8_t secretbytes[64];
212         memset(secretbytes, 0, sizeof(secretbytes));
213         memcpy(secretbytes, assign->key, sizeof(assign->key));
214
215         for (size_t i = 0; i < sizeof(secretbytes); ++i)
216                 secretbytes[i] ^= 0x36;
217
218         md5_begin(&md5);
219         md5_hash(secretbytes, sizeof(secretbytes), &md5);
220         md5_hash(iov.iov_base, iov.iov_len, &md5);
221         md5_end(reconf_msg.auth.key, &md5);
222
223         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
224                 secretbytes[i] ^= 0x36;
225                 secretbytes[i] ^= 0x5c;
226         }
227
228         md5_begin(&md5);
229         md5_hash(secretbytes, sizeof(secretbytes), &md5);
230         md5_hash(reconf_msg.auth.key, 16, &md5);
231         md5_end(reconf_msg.auth.key, &md5);
232
233         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
234 }
235
236 void dhcpv6_write_statefile(void)
237 {
238         md5_ctx_t md5;
239         md5_begin(&md5);
240
241         if (config.dhcp_statefile) {
242                 time_t now = odhcpd_time(), wall_time = time(NULL);
243                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
244                 if (fd < 0)
245                         return;
246
247                 lockf(fd, F_LOCK, 0);
248                 if (ftruncate(fd, 0) < 0) {}
249
250                 FILE *fp = fdopen(fd, "w");
251                 if (!fp) {
252                         close(fd);
253                         return;
254                 }
255
256                 struct interface *iface;
257                 list_for_each_entry(iface, &interfaces, head) {
258                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
259                                 continue;
260
261                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
262                                 struct dhcpv6_assignment *c;
263                                 list_for_each_entry(c, &iface->ia_assignments, head) {
264                                         if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
265                                                 continue;
266
267                                         char ipbuf[INET6_ADDRSTRLEN];
268                                         char leasebuf[512];
269                                         char duidbuf[264];
270                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
271
272                                         /* iface DUID iaid hostname lifetime assigned length [addrs...] */
273                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
274                                                         iface->ifname, duidbuf, ntohl(c->iaid),
275                                                         (c->hostname ? c->hostname : "-"),
276                                                         (c->valid_until > now ?
277                                                                 (c->valid_until - now + wall_time) :
278                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
279                                                         c->assigned, (unsigned)c->length);
280
281                                         struct in6_addr addr;
282                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
283                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
284                                         size_t m = elect_addr(addrs, addrlen);
285
286                                         for (size_t i = 0; i < addrlen; ++i) {
287                                                 if (!valid_addr(&addrs[i], now) ||
288                                                             (!INFINITE_VALID(c->valid_until) && c->valid_until <= now))
289                                                         continue;
290
291                                                 addr = addrs[i].addr;
292                                                 if (c->length == 128) {
293                                                         if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs))
294                                                                 continue;
295
296                                                         addr.s6_addr32[3] = htonl(c->assigned);
297                                                 }
298                                                 else {
299                                                         if (!valid_prefix_length(c, addrs[i].prefix))
300                                                                 continue;
301
302                                                         addr.s6_addr32[1] |= htonl(c->assigned);
303                                                 }
304
305                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
306
307                                                 if (c->length == 128 && c->hostname) {
308                                                         fputs(ipbuf, fp);
309
310                                                         char b[256];
311                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
312                                                                         iface->search, b, sizeof(b)) > 0)
313                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
314
315                                                         fprintf(fp, "\t%s\n", c->hostname);
316                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
317                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
318                                                 }
319
320                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
321                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
322                                         }
323                                         leasebuf[l - 1] = '\n';
324                                         fwrite(leasebuf, 1, l, fp);
325                                 }
326                         }
327
328                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
329                                 struct dhcpv4_assignment *c;
330                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
331                                         if (!(c->flags & OAF_BOUND))
332                                                 continue;
333
334                                         char ipbuf[INET6_ADDRSTRLEN];
335                                         char leasebuf[512];
336                                         char duidbuf[16];
337                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
338
339                                         /* iface DUID iaid hostname lifetime assigned length [addrs...] */
340                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
341                                                         iface->ifname, duidbuf,
342                                                         (c->hostname ? c->hostname : "-"),
343                                                         (c->valid_until > now ?
344                                                                 (c->valid_until - now + wall_time) :
345                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
346                                                         c->addr);
347
348                                         struct in_addr addr = {htonl(c->addr)};
349                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
350
351                                         if (c->hostname) {
352                                                 fputs(ipbuf, fp);
353
354                                                 char b[256];
355                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
356                                                                 iface->search, b, sizeof(b)) > 0)
357                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
358
359                                                 fprintf(fp, "\t%s\n", c->hostname);
360                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
361                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
362                                         }
363
364                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
365                                         leasebuf[l - 1] = '\n';
366                                         fwrite(leasebuf, 1, l, fp);
367                                 }
368                         }
369                 }
370
371                 fclose(fp);
372         }
373
374         uint8_t newmd5[16];
375         md5_end(newmd5, &md5);
376
377         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
378                 memcpy(statemd5, newmd5, sizeof(statemd5));
379                 char *argv[2] = {config.dhcp_cb, NULL};
380                 if (!vfork()) {
381                         execv(argv[0], argv);
382                         _exit(128);
383                 }
384         }
385 }
386
387
388 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
389 {
390         if (a->length > 64 || a->managed_size < 0)
391                 return;
392
393         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
394         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
395
396         for (size_t i = 0; i < addrlen; ++i) {
397                 struct in6_addr prefix = addrs[i].addr;
398                 prefix.s6_addr32[1] |= htonl(a->assigned);
399                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
400                                 iface, &a->peer.sin6_addr, 1024, add);
401         }
402 }
403
404 /* More data was received from TCP connection */
405 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
406 {
407         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
408         time_t now = odhcpd_time();
409         bool first = c->managed_size < 0;
410
411         for (;;) {
412                 int pending;
413                 char *data = ustream_get_read_buf(s, &pending);
414                 char *end = memmem(data, pending, "\n\n", 2);
415
416                 if (!end)
417                         break;
418
419                 end += 2;
420                 end[-1] = 0;
421
422                 c->managed_size = 0;
423                 if (c->accept_reconf)
424                         c->reconf_cnt = 1;
425
426                 char *saveptr;
427                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
428                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
429                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
430
431                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
432                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
433                                 continue;
434
435                         x = strtok_r(NULL, ",", &saveptr2);
436                         if (sscanf(x, "%hhu", &n->prefix) < 1)
437                                 continue;
438
439                         x = strtok_r(NULL, ",", &saveptr2);
440                         if (sscanf(x, "%u", &n->preferred) < 1)
441                                 continue;
442
443                         x = strtok_r(NULL, ",", &saveptr2);
444                         if (sscanf(x, "%u", &n->valid) < 1)
445                                 continue;
446
447                         if (n->preferred > n->valid)
448                                 continue;
449
450                         if (UINT32_MAX - now < n->preferred)
451                                 n->preferred = UINT32_MAX;
452                         else
453                                 n->preferred += now;
454
455                         if (UINT32_MAX - now < n->valid)
456                                 n->valid = UINT32_MAX;
457                         else
458                                 n->valid += now;
459
460                         n->dprefix = 0;
461
462                         ++c->managed_size;
463                 }
464
465                 ustream_consume(s, end - data);
466         }
467
468         if (first && c->managed_size == 0)
469                 free_dhcpv6_assignment(c);
470         else if (first && !(c->flags & OAF_STATIC))
471                 c->valid_until = now + 150;
472 }
473
474
475 /* TCP transmission has ended, either because of success or timeout or other error */
476 static void managed_handle_pd_done(struct ustream *s)
477 {
478         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
479
480         if (!(c->flags & OAF_STATIC))
481                 c->valid_until = odhcpd_time() + 15;
482
483         c->managed_size = 0;
484
485         if (c->accept_reconf)
486                 c->reconf_cnt = 1;
487 }
488
489 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
490 {
491         struct dhcpv6_assignment *c;
492
493         if (iface->dhcpv6_pd_manager[0]) {
494                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
495                 if (fd >= 0) {
496                         char iaidbuf[298];
497                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
498
499                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
500                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
501                         ustream_fd_init(&assign->managed_sock, fd);
502                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
503                                         iaidbuf, assign->iaid, assign->length);
504                         ustream_write_pending(&assign->managed_sock.stream);
505                         assign->managed_size = -1;
506
507                         if (!(assign->flags & OAF_STATIC))
508                                 assign->valid_until = odhcpd_time() + 15;
509
510                         list_add(&assign->head, &iface->ia_assignments);
511
512                         /* Wait initial period of up to 250ms for immediate assignment */
513                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
514                         poll(&pfd, 1, 250);
515                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
516
517                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
518                                 return true;
519                 }
520
521                 return false;
522         } else if (iface->ia_addr_len < 1)
523                 return false;
524
525         /* Try honoring the hint first */
526         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
527         if (assign->assigned) {
528                 list_for_each_entry(c, &iface->ia_assignments, head) {
529                         if (c->length == 128 || c->length == 0)
530                                 continue;
531
532                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
533                                 list_add_tail(&assign->head, &c->head);
534
535                                 if (assign->flags & OAF_BOUND)
536                                         apply_lease(iface, assign, true);
537
538                                 return true;
539                         }
540
541                         if (c->assigned != 0)
542                                 current = (c->assigned + (1 << (64 - c->length)));
543                 }
544         }
545
546         /* Fallback to a variable assignment */
547         current = 1;
548         list_for_each_entry(c, &iface->ia_assignments, head) {
549                 if (c->length == 128 || c->length == 0)
550                         continue;
551
552                 current = (current + asize) & (~asize);
553                 if (current + asize < c->assigned) {
554                         assign->assigned = current;
555                         list_add_tail(&assign->head, &c->head);
556
557                         if (assign->flags & OAF_BOUND)
558                                 apply_lease(iface, assign, true);
559
560                         return true;
561                 }
562
563                 if (c->assigned != 0)
564                         current = (c->assigned + (1 << (64 - c->length)));
565         }
566
567         return false;
568 }
569
570 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
571 {
572         /* Seed RNG with checksum of DUID */
573         uint32_t seed = 0;
574         for (size_t i = 0; i < assign->clid_len; ++i)
575                 seed += assign->clid_data[i];
576         srand(seed);
577
578         /* Try to assign up to 100x */
579         for (size_t i = 0; i < 100; ++i) {
580                 uint32_t try;
581                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
582
583                 struct dhcpv6_assignment *c;
584                 list_for_each_entry(c, &iface->ia_assignments, head) {
585                         if (c->length == 0)
586                                 continue;
587
588                         if (c->assigned > try || c->length != 128) {
589                                 assign->assigned = try;
590                                 list_add_tail(&assign->head, &c->head);
591                                 return true;
592                         } else if (c->assigned == try)
593                                 break;
594                 }
595         }
596
597         return false;
598 }
599
600 void dhcpv6_ia_preupdate(struct interface *iface)
601 {
602         if (iface->dhcpv6 != RELAYD_SERVER)
603                 return;
604
605         struct dhcpv6_assignment *c, *border = list_last_entry(
606                         &iface->ia_assignments, struct dhcpv6_assignment, head);
607
608         list_for_each_entry(c, &iface->ia_assignments, head)
609                 if (c != border && !iface->managed && (c->flags & OAF_BOUND))
610                         apply_lease(iface, c, false);
611 }
612
613 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
614 {
615         if (iface->dhcpv6 != RELAYD_SERVER)
616                 return;
617
618         int minprefix = -1;
619         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
620                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
621                                 iface->ia_addr[i].prefix < 64 &&
622                                 iface->ia_addr[i].prefix > minprefix)
623                         minprefix = iface->ia_addr[i].prefix;
624         }
625
626         struct dhcpv6_assignment *border = list_last_entry(
627                         &iface->ia_assignments, struct dhcpv6_assignment, head);
628
629         if (minprefix > 32 && minprefix <= 64)
630                 border->assigned = 1U << (64 - minprefix);
631         else
632                 border->assigned = 0;
633
634         struct list_head reassign = LIST_HEAD_INIT(reassign);
635         struct dhcpv6_assignment *c, *d;
636         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
637                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
638                                 c->managed_size)
639                         continue;
640
641                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
642                         list_move(&c->head, &reassign);
643                 else if (c != border && (c->flags & OAF_BOUND))
644                         apply_lease(iface, c, true);
645
646                 if (c->accept_reconf && c->reconf_cnt == 0) {
647                         c->reconf_cnt = 1;
648                         c->reconf_sent = now;
649                         send_reconf(iface, c);
650
651                         /* Leave all other assignments of that client alone */
652                         struct dhcpv6_assignment *a;
653                         list_for_each_entry(a, &iface->ia_assignments, head)
654                                 if (a != c && a->clid_len == c->clid_len &&
655                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
656                                         c->reconf_cnt = INT_MAX;
657                 }
658         }
659
660         while (!list_empty(&reassign)) {
661                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
662                 list_del(&c->head);
663                 if (!assign_pd(iface, c)) {
664                         c->assigned = 0;
665                         list_add(&c->head, &iface->ia_assignments);
666                 }
667         }
668
669         dhcpv6_write_statefile();
670 }
671
672 static void reconf_timer(struct uloop_timeout *event)
673 {
674         time_t now = odhcpd_time();
675         struct interface *iface;
676         list_for_each_entry(iface, &interfaces, head) {
677                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
678                         continue;
679
680                 struct dhcpv6_assignment *a, *n;
681                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
682                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
683                                 if ((a->length < 128 && a->clid_len > 0) ||
684                                                 (a->length == 128 && a->clid_len == 0))
685                                         free_dhcpv6_assignment(a);
686
687                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
688                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
689                                 ++a->reconf_cnt;
690                                 a->reconf_sent = now;
691                                 send_reconf(iface, a);
692                         }
693                 }
694         }
695         uloop_timeout_set(event, 2000);
696 }
697
698 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
699                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
700                 struct interface *iface, bool request)
701 {
702         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
703                 return 0;
704
705         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
706         size_t datalen = sizeof(out);
707         time_t now = odhcpd_time();
708
709         if (status) {
710                 struct __attribute__((packed)) {
711                         uint16_t type;
712                         uint16_t len;
713                         uint16_t value;
714                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
715                                 htons(status)};
716
717                 memcpy(buf + datalen, &stat, sizeof(stat));
718                 datalen += sizeof(stat);
719         } else {
720                 if (a) {
721                         uint32_t leasetime;
722                         if (a->leasetime > 0)
723                                 leasetime = a->leasetime;
724                         else
725                                 leasetime = iface->dhcpv4_leasetime;
726
727                         if (leasetime == 0)
728                                 leasetime = 3600;
729                         else if (leasetime < 60)
730                                 leasetime = 60;
731
732                         uint32_t pref = leasetime;
733                         uint32_t valid = leasetime;
734
735                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
736                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
737                         size_t m = elect_addr(addrs, addrlen);
738
739                         for (size_t i = 0; i < addrlen; ++i) {
740                                 uint32_t prefix_pref = addrs[i].preferred;
741                                 uint32_t prefix_valid = addrs[i].valid;
742
743                                 if (!valid_addr(&addrs[i], now))
744                                         continue;
745
746                                 if (prefix_pref != UINT32_MAX)
747                                         prefix_pref -= now;
748
749                                 if (prefix_valid != UINT32_MAX)
750                                         prefix_valid -= now;
751
752                                 if (a->length < 128) {
753                                         struct dhcpv6_ia_prefix p = {
754                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
755                                                 .len = htons(sizeof(p) - 4),
756                                                 .preferred = htonl(prefix_pref),
757                                                 .valid = htonl(prefix_valid),
758                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
759                                                 .addr = addrs[i].addr
760                                         };
761                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
762
763                                         size_t entrlen = sizeof(p) - 4;
764
765                                         if (datalen + entrlen + 4 > buflen ||
766                                                         (a->assigned == 0 && a->managed_size == 0) ||
767                                                         !valid_prefix_length(a, addrs[i].prefix))
768                                                 continue;
769
770                                         memcpy(buf + datalen, &p, sizeof(p));
771                                         datalen += entrlen + 4;
772                                 } else {
773                                         struct dhcpv6_ia_addr n = {
774                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
775                                                 .len = htons(sizeof(n) - 4),
776                                                 .addr = addrs[i].addr,
777                                                 .preferred = htonl(prefix_pref),
778                                                 .valid = htonl(prefix_valid)
779                                         };
780                                         n.addr.s6_addr32[3] = htonl(a->assigned);
781                                         size_t entrlen = sizeof(n) - 4;
782
783                                         if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
784                                                         a->assigned == 0 ||
785                                                         datalen + entrlen + 4 > buflen)
786                                                 continue;
787
788                                         memcpy(buf + datalen, &n, sizeof(n));
789                                         datalen += entrlen + 4;
790                                 }
791
792                                 /* Calculate T1 / T2 based on non-deprecated addresses */
793                                 if (prefix_pref > 0) {
794                                         if (prefix_pref < pref)
795                                                 pref = prefix_pref;
796
797                                         if (prefix_valid < valid)
798                                                 valid = prefix_valid;
799                                 }
800                         }
801
802                         if (!INFINITE_VALID(a->valid_until))
803                                 /* UINT32_MAX is considered as infinite leasetime */
804                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
805
806                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
807                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
808
809                         if (!out.t1)
810                                 out.t1 = htonl(1);
811
812                         if (!out.t2)
813                                 out.t2 = htonl(1);
814                 }
815
816                 if (!request) {
817                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
818                         uint16_t otype, olen;
819                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
820                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
821                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
822                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
823                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
824                                         continue;
825
826                                 bool found = false;
827                                 if (a) {
828                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
829                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
830
831                                         for (size_t i = 0; i < addrlen; ++i) {
832                                                 if (!valid_addr(&addrs[i], now))
833                                                         continue;
834
835                                                 struct in6_addr addr = addrs[i].addr;
836                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
837                                                         addr.s6_addr32[1] |= htonl(a->assigned);
838
839                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
840                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
841                                                                 found = true;
842                                                 } else {
843                                                         addr.s6_addr32[3] = htonl(a->assigned);
844
845                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
846                                                                 found = true;
847                                                 }
848                                         }
849                                 }
850
851                                 if (!found) {
852                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
853                                                 struct dhcpv6_ia_prefix inv = {
854                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
855                                                         .len = htons(sizeof(inv) - 4),
856                                                         .preferred = 0,
857                                                         .valid = 0,
858                                                         .prefix = p->prefix,
859                                                         .addr = p->addr
860                                                 };
861
862                                                 if (datalen + sizeof(inv) > buflen)
863                                                         continue;
864
865                                                 memcpy(buf + datalen, &inv, sizeof(inv));
866                                                 datalen += sizeof(inv);
867                                         } else {
868                                                 struct dhcpv6_ia_addr inv = {
869                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
870                                                         .len = htons(sizeof(inv) - 4),
871                                                         .addr = n->addr,
872                                                         .preferred = 0,
873                                                         .valid = 0
874                                                 };
875
876                                                 if (datalen + sizeof(inv) > buflen)
877                                                         continue;
878
879                                                 memcpy(buf + datalen, &inv, sizeof(inv));
880                                                 datalen += sizeof(inv);
881                                         }
882                                 }
883                         }
884                 }
885         }
886
887         out.len = htons(datalen - 4);
888         memcpy(buf, &out, sizeof(out));
889         return datalen;
890 }
891
892 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
893                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
894 {
895         const char *type = "UNKNOWN";
896         const char *status = "UNKNOWN";
897
898         if (msgtype == DHCPV6_MSG_RENEW)
899                 return;
900
901         switch (msgtype) {
902         case DHCPV6_MSG_SOLICIT:
903                 type = "SOLICIT";
904                 break;
905         case DHCPV6_MSG_REQUEST:
906                 type = "REQUEST";
907                 break;
908         case DHCPV6_MSG_CONFIRM:
909                 type = "CONFIRM";
910                 break;
911         case DHCPV6_MSG_RENEW:
912                 type = "RENEW";
913                 break;
914         case DHCPV6_MSG_REBIND:
915                 type = "REBIND";
916                 break;
917         case DHCPV6_MSG_RELEASE:
918                 type = "RELEASE";
919                 break;
920         case DHCPV6_MSG_DECLINE:
921                 type = "DECLINE";
922                 break;
923         }
924
925         switch (code) {
926         case DHCPV6_STATUS_OK:
927                 status = "ok";
928                 break;
929         case DHCPV6_STATUS_NOADDRSAVAIL:
930                 status = "no addresses available";
931                 break;
932         case DHCPV6_STATUS_NOBINDING:
933                 status = "no binding";
934                 break;
935         case DHCPV6_STATUS_NOTONLINK:
936                 status = "not on-link";
937                 break;
938         case DHCPV6_STATUS_NOPREFIXAVAIL:
939                 status = "no prefix available";
940                 break;
941         }
942
943         char leasebuf[256] = "";
944
945         if (a) {
946                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
947                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
948                 size_t lbsize = 0;
949                 size_t m = elect_addr(addrs, addrlen);
950                 char addrbuf[INET6_ADDRSTRLEN];
951
952                 for (size_t i = 0; i < addrlen; ++i) {
953                         if (!valid_addr(&addrs[i], now))
954                                 continue;
955
956                         struct in6_addr addr = addrs[i].addr;
957                         int prefix = a->managed ? addrs[i].prefix : a->length;
958                         if (prefix == 128) {
959                                 if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
960                                                 a->assigned == 0)
961                                         continue;
962
963                                 addr.s6_addr32[3] = htonl(a->assigned);
964                         }
965                         else {
966                                 if (!valid_prefix_length(a, addrs[i].prefix))
967                                         continue;
968
969                                 addr.s6_addr32[1] |= htonl(a->assigned);
970                         }
971
972                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
973                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
974                 }
975         }
976
977         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
978                         duidbuf, iface->ifname, status, leasebuf);
979 }
980
981 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
982                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
983 {
984         time_t now = odhcpd_time();
985         size_t response_len = 0;
986         const struct dhcpv6_client_header *hdr = data;
987         uint8_t *start = (uint8_t*)&hdr[1], *odata;
988         uint16_t otype, olen;
989         /* Find and parse client-id and hostname */
990         bool accept_reconf = false;
991         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
992         char hostname[256];
993         size_t hostname_len = 0;
994         bool notonlink = false;
995         char duidbuf[261];
996
997         dhcpv6_for_each_option(start, end, otype, olen, odata) {
998                 if (otype == DHCPV6_OPT_CLIENTID) {
999                         clid_data = odata;
1000                         clid_len = olen;
1001
1002                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
1003                                 memcpy(mac, &odata[8], sizeof(mac));
1004                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
1005                                 memcpy(mac, &odata[4], sizeof(mac));
1006
1007                         if (olen <= 130)
1008                                 odhcpd_hexlify(duidbuf, odata, olen);
1009                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
1010                         uint8_t fqdn_buf[256];
1011                         memcpy(fqdn_buf, odata, olen);
1012                         fqdn_buf[olen++] = 0;
1013
1014                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
1015                                 hostname_len = strcspn(hostname, ".");
1016                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT)
1017                         accept_reconf = true;
1018         }
1019
1020         if (!clid_data || !clid_len || clid_len > 130)
1021                 goto out;
1022
1023         struct dhcpv6_assignment *first = NULL;
1024         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1025                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1026                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1027                 bool ia_addr_present = false;
1028                 if (!is_pd && !is_na)
1029                         continue;
1030
1031                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1032                 size_t ia_response_len = 0;
1033                 uint8_t reqlen = (is_pd) ? 62 : 128;
1034                 uint32_t reqhint = 0;
1035
1036                 /* Parse request hint for IA-PD */
1037                 if (is_pd) {
1038                         uint8_t *sdata;
1039                         uint16_t stype, slen;
1040                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1041                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1042                                         continue;
1043
1044                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1045                                 if (p->prefix) {
1046                                         reqlen = p->prefix;
1047                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1048                                         if (reqlen > 32 && reqlen <= 64)
1049                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1050                                 }
1051                         }
1052
1053                         if (reqlen > 64)
1054                                 reqlen = 64;
1055                 } else if (is_na) {
1056                         uint8_t *sdata;
1057                         uint16_t stype, slen;
1058                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1059                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1060                                         continue;
1061
1062                                 ia_addr_present = true;
1063                         }
1064                 }
1065
1066                 /* Find assignment */
1067                 struct dhcpv6_assignment *c, *a = NULL;
1068                 list_for_each_entry(c, &iface->ia_assignments, head) {
1069                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1070                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1071                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1072                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1073                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1074                                 a = c;
1075
1076                                 /* Reset state */
1077                                 if (a->flags & OAF_BOUND)
1078                                         apply_lease(iface, a, false);
1079
1080                                 memcpy(a->clid_data, clid_data, clid_len);
1081                                 a->clid_len = clid_len;
1082                                 a->iaid = ia->iaid;
1083                                 a->peer = *addr;
1084                                 a->reconf_cnt = 0;
1085                                 a->reconf_sent = 0;
1086                                 break;
1087                         }
1088                 }
1089
1090                 /* Generic message handling */
1091                 uint16_t status = DHCPV6_STATUS_OK;
1092                 if (a && a->managed_size < 0)
1093                         return -1;
1094
1095                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1096                         bool assigned = !!a;
1097
1098                         if (!a && !iface->no_dynamic_dhcp) {
1099                                 /* Create new binding */
1100                                 a = calloc(1, sizeof(*a) + clid_len);
1101                                 if (a) {
1102                                         a->clid_len = clid_len;
1103                                         a->iaid = ia->iaid;
1104                                         a->length = reqlen;
1105                                         a->peer = *addr;
1106                                         a->assigned = reqhint;
1107                                         /* Set valid time to current time indicating  */
1108                                         /* assignment is not having infinite lifetime */
1109                                         a->valid_until = now;
1110
1111                                         if (first)
1112                                                 memcpy(a->key, first->key, sizeof(a->key));
1113                                         else
1114                                                 odhcpd_urandom(a->key, sizeof(a->key));
1115                                         memcpy(a->clid_data, clid_data, clid_len);
1116
1117                                         if (is_pd)
1118                                                 while (!(assigned = assign_pd(iface, a)) &&
1119                                                                 !a->managed_size && ++a->length <= 64);
1120                                         else
1121                                                 assigned = assign_na(iface, a);
1122
1123                                         if (a->managed_size && !assigned)
1124                                                 return -1;
1125                                 }
1126                         }
1127
1128                         if (!assigned || iface->ia_addr_len == 0)
1129                                 /* Set error status */
1130                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1131                         else if (assigned && !first) {
1132                                 size_t handshake_len = 4;
1133                                 buf[0] = 0;
1134                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1135                                 buf[2] = 0;
1136                                 buf[3] = 0;
1137
1138                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1139                                         struct dhcpv6_auth_reconfigure auth = {
1140                                                 htons(DHCPV6_OPT_AUTH),
1141                                                 htons(sizeof(auth) - 4),
1142                                                 3, 1, 0,
1143                                                 {htonl(time(NULL)), htonl(++serial)},
1144                                                 1,
1145                                                 {0}
1146                                         };
1147                                         memcpy(auth.key, a->key, sizeof(a->key));
1148                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1149                                         handshake_len += sizeof(auth);
1150                                 }
1151
1152                                 buf += handshake_len;
1153                                 buflen -= handshake_len;
1154                                 response_len += handshake_len;
1155
1156                                 first = a;
1157                         }
1158
1159                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1160
1161                         /* Was only a solicitation: mark binding for removal */
1162                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1163                                 a->flags &= ~OAF_BOUND;
1164
1165                                 if (!(a->flags & OAF_STATIC))
1166                                         a->valid_until = now;
1167                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1168                                 if (hostname_len > 0) {
1169                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1170                                         if (a->hostname) {
1171                                                 memcpy(a->hostname, hostname, hostname_len);
1172                                                 a->hostname[hostname_len] = 0;
1173                                         }
1174                                 }
1175                                 a->accept_reconf = accept_reconf;
1176                                 a->flags |= OAF_BOUND;
1177                                 apply_lease(iface, a, true);
1178                         } else if (!assigned && a && a->managed_size == 0) {
1179                                 /* Cleanup failed assignment */
1180                                 free_dhcpv6_assignment(a);
1181                                 a = NULL;
1182                         }
1183                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1184                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1185                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1186                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1187                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1188                                 status = DHCPV6_STATUS_NOBINDING;
1189                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1190                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1191                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1192                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1193                                 if (a) {
1194                                         a->flags |= OAF_BOUND;
1195                                         apply_lease(iface, a, true);
1196                                 }
1197                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1198                                 if (!(a->flags & OAF_STATIC))
1199                                         a->valid_until = now - 1;
1200
1201                                 if (a->flags & OAF_BOUND) {
1202                                         apply_lease(iface, a, false);
1203                                         a->flags &= ~OAF_BOUND;
1204                                 }
1205                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1206                                 a->flags &= ~OAF_BOUND;
1207
1208                                 if (!(a->flags & OAF_STATIC)) {
1209                                         a->clid_len = 0;
1210                                         a->valid_until = now + 3600; /* Block address for 1h */
1211                                 }
1212                         }
1213                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1214                         /* Send NOTONLINK for CONFIRM with addr present so that clients restart connection */
1215                         status = DHCPV6_STATUS_NOTONLINK;
1216                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1217                         notonlink = true;
1218                 }
1219
1220                 buf += ia_response_len;
1221                 buflen -= ia_response_len;
1222                 response_len += ia_response_len;
1223                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1224         }
1225
1226         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1227                         response_len + 6 < buflen) {
1228                 buf[0] = 0;
1229                 buf[1] = DHCPV6_OPT_STATUS;
1230                 buf[2] = 0;
1231                 buf[3] = 2;
1232                 buf[4] = 0;
1233                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1234                 response_len += 6;
1235         }
1236
1237         dhcpv6_write_statefile();
1238
1239 out:
1240         return response_len;
1241 }