src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19 #include "libubox/usock.h"
  20
  21 #include <time.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <stdio.h>
  25 #include <poll.h>
  26 #include <alloca.h>
  27 #include <resolv.h>
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <stdbool.h>
  33 #include <arpa/inet.h>
  34 #include <sys/timerfd.h>
  35
  36
  37 static void update(struct interface *iface);
  38 static void reconf_timer(struct uloop_timeout *event);
  39 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  40 static uint32_t serial = 0;
  41 static uint8_t statemd5[16];
  42
  43
  44 int dhcpv6_ia_init(void)
  45 {
  46         uloop_timeout_set(&reconf_event, 2000);
  47         return 0;
  48 }
  49
  50
  51 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  52 {
  53         if (c->managed_sock.fd.registered) {
  54                 ustream_free(&c->managed_sock.stream);
  55                 close(c->managed_sock.fd.fd);
  56         }
  57
  58         if (c->head.next)
  59                 list_del(&c->head);
  60
  61         free(c->managed);
  62         free(c->hostname);
  63         free(c->classes);
  64         free(c);
  65 }
  66
  67
  68 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  69 {
  70         if (!enable && iface->ia_assignments.next) {
  71                 struct dhcpv6_assignment *c;
  72                 while (!list_empty(&iface->ia_assignments)) {
  73                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  74                         free_dhcpv6_assignment(c);
  75                 }
  76         }
  77
  78         if (iface->dhcpv6 == RELAYD_SERVER) {
  79                 if (!iface->ia_assignments.next)
  80                         INIT_LIST_HEAD(&iface->ia_assignments);
  81
  82                 if (list_empty(&iface->ia_assignments)) {
  83                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  84                         if (!border) {
  85                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  86                                 return -1;
  87                         }
  88
  89                         border->length = 64;
  90                         list_add(&border->head, &iface->ia_assignments);
  91                 }
  92
  93                 update(iface);
  94
  95                 // Parse static entries
  96                 struct lease *lease;
  97                 list_for_each_entry(lease, &leases, head) {
  98                         // Construct entry
  99                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
 100                         if (!a) {
 101                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
 102                                         iface->ifname);
 103                                 return -1;
 104                         }
 105
 106                         a->clid_len = lease->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, a->clid_len);
 116                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 117
 118                         // Assign to all interfaces
 119                         struct dhcpv6_assignment *c;
 120                         list_for_each_entry(c, &iface->ia_assignments, head) {
 121                                 if (c->length != 128 || c->assigned > a->assigned) {
 122                                         list_add_tail(&a->head, &c->head);
 123                                         break;
 124                                 } else if (c->assigned == a->assigned) {
 125                                         // Already an assignment with that number
 126                                         break;
 127                                 }
 128                         }
 129
 130                         if (a->head.next) {
 131                                 if (lease->hostname[0]) {
 132                                         free(a->hostname);
 133                                         a->hostname = strdup(lease->hostname);
 134                                 }
 135                         } else {
 136                                 free(a->classes);
 137                                 free(a->hostname);
 138                                 free(a);
 139                         }
 140                 }
 141         }
 142         return 0;
 143 }
 144
 145
 146 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 147 {
 148         struct {
 149                 struct dhcpv6_client_header hdr;
 150                 uint16_t srvid_type;
 151                 uint16_t srvid_len;
 152                 uint16_t duid_type;
 153                 uint16_t hardware_type;
 154                 uint8_t mac[6];
 155                 uint16_t msg_type;
 156                 uint16_t msg_len;
 157                 uint8_t msg_id;
 158                 struct dhcpv6_auth_reconfigure auth;
 159                 uint16_t clid_type;
 160                 uint16_t clid_len;
 161                 uint8_t clid_data[128];
 162         } __attribute__((packed)) reconf_msg = {
 163                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 164                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 165                 .srvid_len = htons(10),
 166                 .duid_type = htons(3),
 167                 .hardware_type = htons(1),
 168                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 169                 .msg_len = htons(1),
 170                 .msg_id = DHCPV6_MSG_RENEW,
 171                 .auth = {htons(DHCPV6_OPT_AUTH),
 172                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 173                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 174                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 175                 .clid_len = htons(assign->clid_len),
 176                 .clid_data = {0},
 177         };
 178
 179         odhcpd_get_mac(iface, reconf_msg.mac);
 180         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 181         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 182
 183         md5_ctx_t md5;
 184         uint8_t secretbytes[64];
 185         memset(secretbytes, 0, sizeof(secretbytes));
 186         memcpy(secretbytes, assign->key, sizeof(assign->key));
 187
 188         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 189                 secretbytes[i] ^= 0x36;
 190
 191         md5_begin(&md5);
 192         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 193         md5_hash(iov.iov_base, iov.iov_len, &md5);
 194         md5_end(reconf_msg.auth.key, &md5);
 195
 196         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 197                 secretbytes[i] ^= 0x36;
 198                 secretbytes[i] ^= 0x5c;
 199         }
 200
 201         md5_begin(&md5);
 202         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 203         md5_hash(reconf_msg.auth.key, 16, &md5);
 204         md5_end(reconf_msg.auth.key, &md5);
 205
 206         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 207 }
 208
 209
 210 void dhcpv6_write_statefile(void)
 211 {
 212         md5_ctx_t md5;
 213         md5_begin(&md5);
 214
 215         if (config.dhcp_statefile) {
 216                 time_t now = odhcpd_time(), wall_time = time(NULL);
 217                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 218                 if (fd < 0)
 219                         return;
 220
 221                 lockf(fd, F_LOCK, 0);
 222                 ftruncate(fd, 0);
 223
 224                 FILE *fp = fdopen(fd, "w");
 225                 if (!fp) {
 226                         close(fd);
 227                         return;
 228                 }
 229
 230                 struct interface *iface;
 231                 list_for_each_entry(iface, &interfaces, head) {
 232                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 233                                 continue;
 234
 235                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 236                                 struct dhcpv6_assignment *c;
 237                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 238                                         if (c->clid_len == 0 || c->managed_size < 0)
 239                                                 continue;
 240
 241                                         char ipbuf[INET6_ADDRSTRLEN];
 242                                         char leasebuf[512];
 243                                         char duidbuf[264];
 244                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 245
 246                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 247                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 248                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 249                                                         (c->hostname ? c->hostname : "-"),
 250                                                         (unsigned)(c->valid_until > now ?
 251                                                                         (c->valid_until - now + wall_time) : 0),
 252                                                         c->assigned, (unsigned)c->length);
 253
 254                                         struct in6_addr addr;
 255                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 256                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 257                                         size_t mostpref = 0;
 258
 259                                         for (size_t i = 0; i < addrlen; ++i)
 260                                                 if (addrs[i].preferred > addrs[mostpref].preferred)
 261                                                         mostpref = i;
 262
 263                                         for (size_t i = 0; i < addrlen; ++i) {
 264                                                 if (addrs[i].prefix > 96 || c->valid_until <= now ||
 265                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != mostpref))
 266                                                         continue;
 267
 268                                                 addr = addrs[i].addr;
 269                                                 if (c->length == 128)
 270                                                         addr.s6_addr32[3] = htonl(c->assigned);
 271                                                 else
 272                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 273
 274                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 275
 276                                                 if (c->length == 128 && c->hostname) {
 277                                                         fputs(ipbuf, fp);
 278
 279                                                         char b[256];
 280                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 281                                                                         iface->search, b, sizeof(b)) > 0)
 282                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 283
 284                                                         fprintf(fp, "\t%s\n", c->hostname);
 285                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 286                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 287                                                 }
 288
 289                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 290                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 291                                         }
 292                                         leasebuf[l - 1] = '\n';
 293                                         fwrite(leasebuf, 1, l, fp);
 294                                 }
 295                         }
 296
 297                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 298                                 struct dhcpv4_assignment *c;
 299                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 300                                         char ipbuf[INET6_ADDRSTRLEN];
 301                                         char leasebuf[512];
 302                                         char duidbuf[16];
 303                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 304
 305                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 306                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 307                                                         iface->ifname, duidbuf,
 308                                                         (c->hostname ? c->hostname : "-"),
 309                                                         (unsigned)(c->valid_until > now ?
 310                                                                         (c->valid_until - now + wall_time) : 0),
 311                                                         c->addr);
 312
 313                                         struct in_addr addr = {htonl(c->addr)};
 314                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 315
 316                                         if (c->hostname[0]) {
 317                                                 fputs(ipbuf, fp);
 318
 319                                                 char b[256];
 320                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 321                                                                 iface->search, b, sizeof(b)) > 0)
 322                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 323
 324                                                 fprintf(fp, "\t%s\n", c->hostname);
 325                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 326                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 327                                         }
 328
 329                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 330                                         leasebuf[l - 1] = '\n';
 331                                         fwrite(leasebuf, 1, l, fp);
 332                                 }
 333                         }
 334                 }
 335
 336                 fclose(fp);
 337         }
 338
 339         uint8_t newmd5[16];
 340         md5_end(newmd5, &md5);
 341
 342         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 343                 memcpy(statemd5, newmd5, sizeof(statemd5));
 344                 char *argv[2] = {config.dhcp_cb, NULL};
 345                 if (!vfork()) {
 346                         execv(argv[0], argv);
 347                         _exit(128);
 348                 }
 349         }
 350 }
 351
 352
 353 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 354 {
 355         if (a->length > 64 || a->managed_size < 0)
 356                 return;
 357
 358         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 359         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 360
 361         for (size_t i = 0; i < addrlen; ++i) {
 362                 struct in6_addr prefix = addrs[i].addr;
 363                 prefix.s6_addr32[1] |= htonl(a->assigned);
 364                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 365                                 iface, &a->peer.sin6_addr, add);
 366         }
 367 }
 368
 369
 370 // More data was received from TCP connection
 371 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 372 {
 373         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 374         time_t now = odhcpd_time();
 375         bool first = c->managed_size < 0;
 376
 377         for (;;) {
 378                 int pending;
 379                 char *data = ustream_get_read_buf(s, &pending);
 380                 char *end = memmem(data, pending, "\n\n", 2);
 381
 382                 if (!end)
 383                         break;
 384
 385                 end += 2;
 386                 end[-1] = 0;
 387
 388                 c->managed_size = 0;
 389                 if (c->accept_reconf)
 390                         c->reconf_cnt = 1;
 391
 392                 char *saveptr;
 393                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 394                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 395                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 396
 397                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 398                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 399                                 continue;
 400
 401                         x = strtok_r(NULL, ",", &saveptr2);
 402                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 403                                 continue;
 404
 405                         x = strtok_r(NULL, ",", &saveptr2);
 406                         if (sscanf(x, "%u", &n->preferred) < 1)
 407                                 continue;
 408
 409                         x = strtok_r(NULL, ",", &saveptr2);
 410                         if (sscanf(x, "%u", &n->valid) < 1)
 411                                 continue;
 412
 413                         if (n->preferred > n->valid)
 414                                 continue;
 415
 416                         if (UINT32_MAX - now < n->preferred)
 417                                 n->preferred = UINT32_MAX;
 418                         else
 419                                 n->preferred += now;
 420
 421                         if (UINT32_MAX - now < n->valid)
 422                                 n->valid = UINT32_MAX;
 423                         else
 424                                 n->valid += now;
 425
 426                         n->dprefix = 0;
 427
 428                         ++c->managed_size;
 429                 }
 430
 431                 ustream_consume(s, end - data);
 432         }
 433
 434         if (first && c->managed_size == 0)
 435                 free_dhcpv6_assignment(c);
 436         else if (first)
 437                 c->valid_until = now + 150;
 438 }
 439
 440
 441 // TCP transmission has ended, either because of success or timeout or other error
 442 static void managed_handle_pd_done(struct ustream *s)
 443 {
 444         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 445         c->valid_until = odhcpd_time() + 15;
 446         c->managed_size = 0;
 447         if (c->accept_reconf)
 448                 c->reconf_cnt = 1;
 449 }
 450
 451
 452
 453 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 454 {
 455         struct dhcpv6_assignment *c;
 456
 457         if (iface->dhcpv6_pd_manager[0]) {
 458                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 459                 if (fd >= 0) {
 460                         char iaidbuf[298];
 461                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 462
 463                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 464                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 465                         ustream_fd_init(&assign->managed_sock, fd);
 466                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 467                                         iaidbuf, assign->iaid, assign->length);
 468                         ustream_write_pending(&assign->managed_sock.stream);
 469                         assign->managed_size = -1;
 470                         assign->valid_until = odhcpd_time() + 15;
 471                         list_add(&assign->head, &iface->ia_assignments);
 472
 473                         // Wait initial period of up to 250ms for immediate assignment
 474                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 475                         poll(&pfd, 1, 250);
 476                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 477
 478                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 479                                 return true;
 480                 }
 481
 482                 return false;
 483         } else if (iface->ia_addr_len < 1) {
 484                 return false;
 485         }
 486
 487         // Try honoring the hint first
 488         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 489         if (assign->assigned) {
 490                 list_for_each_entry(c, &iface->ia_assignments, head) {
 491                         if (c->length == 128 || c->length == 0)
 492                                 continue;
 493
 494                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 495                                 list_add_tail(&assign->head, &c->head);
 496                                 apply_lease(iface, assign, true);
 497                                 return true;
 498                         }
 499
 500                         if (c->assigned != 0)
 501                                 current = (c->assigned + (1 << (64 - c->length)));
 502                 }
 503         }
 504
 505         // Fallback to a variable assignment
 506         current = 1;
 507         list_for_each_entry(c, &iface->ia_assignments, head) {
 508                 if (c->length == 128 || c->length == 0)
 509                         continue;
 510
 511                 current = (current + asize) & (~asize);
 512                 if (current + asize < c->assigned) {
 513                         assign->assigned = current;
 514                         list_add_tail(&assign->head, &c->head);
 515                         apply_lease(iface, assign, true);
 516                         return true;
 517                 }
 518
 519                 if (c->assigned != 0)
 520                         current = (c->assigned + (1 << (64 - c->length)));
 521         }
 522
 523         return false;
 524 }
 525
 526
 527 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 528 {
 529         // Seed RNG with checksum of DUID
 530         uint32_t seed = 0;
 531         for (size_t i = 0; i < assign->clid_len; ++i)
 532                 seed += assign->clid_data[i];
 533         srand(seed);
 534
 535         // Try to assign up to 100x
 536         for (size_t i = 0; i < 100; ++i) {
 537                 uint32_t try;
 538                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 539
 540                 struct dhcpv6_assignment *c;
 541                 list_for_each_entry(c, &iface->ia_assignments, head) {
 542                         if (c->length == 0)
 543                                 continue;
 544
 545                         if (c->assigned > try || c->length != 128) {
 546                                 assign->assigned = try;
 547                                 list_add_tail(&assign->head, &c->head);
 548                                 return true;
 549                         } else if (c->assigned == try) {
 550                                 break;
 551                         }
 552                 }
 553         }
 554
 555         return false;
 556 }
 557
 558
 559 static int prefixcmp(const void *va, const void *vb)
 560 {
 561         const struct odhcpd_ipaddr *a = va, *b = vb;
 562         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 563         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 564         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 565 }
 566
 567
 568 static void update(struct interface *iface)
 569 {
 570         struct odhcpd_ipaddr addr[8];
 571         memset(addr, 0, sizeof(addr));
 572         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 573
 574         if (len < 0)
 575                 return;
 576
 577         qsort(addr, len, sizeof(*addr), prefixcmp);
 578
 579         time_t now = odhcpd_time();
 580         int minprefix = -1;
 581
 582         for (int i = 0; i < len; ++i) {
 583                 if (addr[i].preferred > 0 && addr[i].prefix > minprefix)
 584                         minprefix = addr[i].prefix;
 585
 586                 addr[i].addr.s6_addr32[3] = 0;
 587
 588                 if (addr[i].preferred < UINT32_MAX - now)
 589                         addr[i].preferred += now;
 590
 591                 if (addr[i].valid < UINT32_MAX - now)
 592                         addr[i].valid += now;
 593         }
 594
 595         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 596         border->assigned = 1 << (64 - minprefix);
 597
 598         bool change = len != (int)iface->ia_addr_len;
 599         for (int i = 0; !change && i < len; ++i)
 600                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 601                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 602                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 603                                 (addr[i].valid > (uint32_t)now + 7200) !=
 604                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 605                         change = true;
 606
 607         if (change) {
 608                 struct dhcpv6_assignment *c;
 609                 list_for_each_entry(c, &iface->ia_assignments, head)
 610                         if (c != border && !iface->managed)
 611                                 apply_lease(iface, c, false);
 612         }
 613
 614         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 615         iface->ia_addr_len = len;
 616
 617         if (change) { // Addresses / prefixes have changed
 618                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 619                 struct dhcpv6_assignment *c, *d;
 620                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 621                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 622                                 continue;
 623
 624                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 625                                 list_move(&c->head, &reassign);
 626                         else if (c != border)
 627                                 apply_lease(iface, c, true);
 628
 629                         if (c->accept_reconf && c->reconf_cnt == 0) {
 630                                 c->reconf_cnt = 1;
 631                                 c->reconf_sent = now;
 632                                 send_reconf(iface, c);
 633
 634                                 // Leave all other assignments of that client alone
 635                                 struct dhcpv6_assignment *a;
 636                                 list_for_each_entry(a, &iface->ia_assignments, head)
 637                                         if (a != c && a->clid_len == c->clid_len &&
 638                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 639                                                 c->reconf_cnt = INT_MAX;
 640                         }
 641                 }
 642
 643                 while (!list_empty(&reassign)) {
 644                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 645                         list_del(&c->head);
 646                         if (!assign_pd(iface, c)) {
 647                                 c->assigned = 0;
 648                                 list_add(&c->head, &iface->ia_assignments);
 649                         }
 650                 }
 651
 652                 dhcpv6_write_statefile();
 653         }
 654 }
 655
 656
 657 static void reconf_timer(struct uloop_timeout *event)
 658 {
 659         time_t now = odhcpd_time();
 660         struct interface *iface;
 661         list_for_each_entry(iface, &interfaces, head) {
 662                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 663                         continue;
 664
 665                 struct dhcpv6_assignment *a, *n;
 666                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 667                         if (a->valid_until < now) {
 668                                 if ((a->length < 128 && a->clid_len > 0) ||
 669                                                 (a->length == 128 && a->clid_len == 0)) {
 670                                         list_del(&a->head);
 671                                         free_dhcpv6_assignment(a);
 672                                 }
 673                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 674                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 675                                 ++a->reconf_cnt;
 676                                 a->reconf_sent = now;
 677                                 send_reconf(iface, a);
 678                         }
 679                 }
 680         }
 681         uloop_timeout_set(event, 2000);
 682 }
 683
 684
 685 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 686                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 687                 struct interface *iface, bool request)
 688 {
 689         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 690                 return 0;
 691
 692         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 693         size_t datalen = sizeof(out);
 694         time_t now = odhcpd_time();
 695
 696         if (status) {
 697                 struct __attribute__((packed)) {
 698                         uint16_t type;
 699                         uint16_t len;
 700                         uint16_t value;
 701                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 702                                 htons(status)};
 703
 704                 memcpy(buf + datalen, &stat, sizeof(stat));
 705                 datalen += sizeof(stat);
 706         } else {
 707                 if (a) {
 708                         uint32_t leasetime = iface->dhcpv4_leasetime;
 709                         if (leasetime == 0)
 710                                 leasetime = 3600;
 711                         else if (leasetime < 60)
 712                                 leasetime = 60;
 713
 714                         uint32_t pref = leasetime;
 715                         uint32_t valid = leasetime;
 716
 717                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 718                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 719                         size_t mostpref = 0;
 720
 721                         for (size_t i = 0; i < addrlen; ++i)
 722                                 if (addrs[i].preferred > addrs[mostpref].preferred)
 723                                         mostpref = i;
 724
 725                         for (size_t i = 0; i < addrlen; ++i) {
 726                                 uint32_t prefix_pref = addrs[i].preferred - now;
 727                                 uint32_t prefix_valid = addrs[i].valid - now;
 728
 729                                 if (addrs[i].prefix > 96 ||
 730                                                 addrs[i].preferred <= (uint32_t)now)
 731                                         continue;
 732
 733                                 if (a->length < 128) {
 734                                         struct dhcpv6_ia_prefix p = {
 735                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 736                                                 .len = htons(sizeof(p) - 4),
 737                                                 .preferred = htonl(prefix_pref),
 738                                                 .valid = htonl(prefix_valid),
 739                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 740                                                 .addr = addrs[i].addr
 741                                         };
 742                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 743
 744                                         size_t entrlen = sizeof(p) - 4;
 745
 746                                         if (datalen + entrlen + 4 > buflen ||
 747                                                         (a->assigned == 0 && a->managed_size == 0))
 748                                                 continue;
 749
 750                                         memcpy(buf + datalen, &p, sizeof(p));
 751                                         datalen += entrlen + 4;
 752                                 } else {
 753                                         struct dhcpv6_ia_addr n = {
 754                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 755                                                 .len = htons(sizeof(n) - 4),
 756                                                 .addr = addrs[i].addr,
 757                                                 .preferred = htonl(prefix_pref),
 758                                                 .valid = htonl(prefix_valid)
 759                                         };
 760                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 761                                         size_t entrlen = sizeof(n) - 4;
 762
 763                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != mostpref)
 764                                                 continue;
 765
 766                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 767                                                 continue;
 768
 769                                         memcpy(buf + datalen, &n, sizeof(n));
 770                                         datalen += entrlen + 4;
 771                                 }
 772
 773                                 // Calculate T1 / T2 based on non-deprecated addresses
 774                                 if (prefix_pref > 0) {
 775                                         if (prefix_pref < pref)
 776                                                 pref = prefix_pref;
 777
 778                                         if (prefix_valid < valid)
 779                                                 valid = prefix_valid;
 780                                 }
 781                         }
 782
 783                         a->valid_until = valid + now;
 784                         out.t1 = htonl(pref * 5 / 10);
 785                         out.t2 = htonl(pref * 8 / 10);
 786
 787                         if (!out.t1)
 788                                 out.t1 = htonl(1);
 789
 790                         if (!out.t2)
 791                                 out.t2 = htonl(1);
 792                 }
 793
 794                 if (!request) {
 795                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 796                         uint16_t otype, olen;
 797                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 798                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 799                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 800                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 801                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 802                                         continue;
 803
 804                                 bool found = false;
 805                                 if (a) {
 806                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 807                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 808
 809                                         for (size_t i = 0; i < addrlen; ++i) {
 810                                                 if (addrs[i].prefix > 96 ||
 811                                                                 addrs[i].preferred <= (uint32_t)now)
 812                                                         continue;
 813
 814                                                 struct in6_addr addr = addrs[i].addr;
 815                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 816                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 817
 818                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 819                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 820                                                                 found = true;
 821                                                 } else {
 822                                                         addr.s6_addr32[3] = htonl(a->assigned);
 823
 824                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 825                                                                 found = true;
 826                                                 }
 827                                         }
 828                                 }
 829
 830                                 if (!found) {
 831                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 832                                                 struct dhcpv6_ia_prefix inv = {
 833                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 834                                                         .len = htons(sizeof(inv) - 4),
 835                                                         .preferred = 0,
 836                                                         .valid = 0,
 837                                                         .prefix = p->prefix,
 838                                                         .addr = p->addr
 839                                                 };
 840
 841                                                 if (datalen + sizeof(inv) > buflen)
 842                                                         continue;
 843
 844                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 845                                                 datalen += sizeof(inv);
 846                                         } else {
 847                                                 struct dhcpv6_ia_addr inv = {
 848                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 849                                                         .len = htons(sizeof(inv) - 4),
 850                                                         .addr = n->addr,
 851                                                         .preferred = 0,
 852                                                         .valid = 0
 853                                                 };
 854
 855                                                 if (datalen + sizeof(inv) > buflen)
 856                                                         continue;
 857
 858                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 859                                                 datalen += sizeof(inv);
 860                                         }
 861                                 }
 862                         }
 863                 }
 864         }
 865
 866         out.len = htons(datalen - 4);
 867         memcpy(buf, &out, sizeof(out));
 868         return datalen;
 869 }
 870
 871
 872 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 873                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 874 {
 875         const char *type = "UNKNOWN";
 876         const char *status = "UNKNOWN";
 877
 878         if (msgtype == DHCPV6_MSG_RENEW)
 879                 return;
 880
 881         switch (msgtype) {
 882         case DHCPV6_MSG_SOLICIT:
 883                 type = "SOLICIT";
 884                 break;
 885         case DHCPV6_MSG_REQUEST:
 886                 type = "REQUEST";
 887                 break;
 888         case DHCPV6_MSG_CONFIRM:
 889                 type = "CONFIRM";
 890                 break;
 891         case DHCPV6_MSG_RENEW:
 892                 type = "RENEW";
 893                 break;
 894         case DHCPV6_MSG_REBIND:
 895                 type = "REBIND";
 896                 break;
 897         case DHCPV6_MSG_RELEASE:
 898                 type = "RELEASE";
 899                 break;
 900         case DHCPV6_MSG_DECLINE:
 901                 type = "DECLINE";
 902                 break;
 903         }
 904
 905         switch (code) {
 906         case DHCPV6_STATUS_OK:
 907                 status = "ok";
 908                 break;
 909         case DHCPV6_STATUS_NOADDRSAVAIL:
 910                 status = "no addresses available";
 911                 break;
 912         case DHCPV6_STATUS_NOBINDING:
 913                 status = "no binding";
 914                 break;
 915         case DHCPV6_STATUS_NOTONLINK:
 916                 status = "not on-link";
 917                 break;
 918         case DHCPV6_STATUS_NOPREFIXAVAIL:
 919                 status = "no prefix available";
 920                 break;
 921         }
 922
 923         char leasebuf[256] = "";
 924
 925         if (a) {
 926                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 927                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 928                 size_t lbsize = 0;
 929                 char addrbuf[INET6_ADDRSTRLEN];
 930
 931                 for (size_t i = 0; i < addrlen; ++i) {
 932                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 933                                 continue;
 934
 935                         struct in6_addr addr = addrs[i].addr;
 936                         int prefix = a->managed ? addrs[i].prefix : a->length;
 937                         if (prefix == 128)
 938                                 addr.s6_addr32[3] = htonl(a->assigned);
 939                         else
 940                                 addr.s6_addr32[1] |= htonl(a->assigned);
 941
 942                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 943                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 944                 }
 945         }
 946
 947         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 948                         duidbuf, iface->ifname, status, leasebuf);
 949 }
 950
 951
 952
 953 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 954                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 955 {
 956         time_t now = odhcpd_time();
 957         size_t response_len = 0;
 958         const struct dhcpv6_client_header *hdr = data;
 959         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 960         uint16_t otype, olen;
 961
 962         // Find and parse client-id and hostname
 963         bool accept_reconf = false;
 964         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 965         char hostname[256];
 966         size_t hostname_len = 0;
 967         bool notonlink = false;
 968         char duidbuf[261];
 969
 970         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 971                 if (otype == DHCPV6_OPT_CLIENTID) {
 972                         clid_data = odata;
 973                         clid_len = olen;
 974
 975                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 976                                 memcpy(mac, &odata[8], sizeof(mac));
 977                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 978                                 memcpy(mac, &odata[4], sizeof(mac));
 979
 980                         if (olen <= 130)
 981                                 odhcpd_hexlify(duidbuf, odata, olen);
 982                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 983                         uint8_t fqdn_buf[256];
 984                         memcpy(fqdn_buf, odata, olen);
 985                         fqdn_buf[olen++] = 0;
 986
 987                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 988                                 hostname_len = strcspn(hostname, ".");
 989                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 990                         accept_reconf = true;
 991                 }
 992         }
 993
 994         if (!clid_data || !clid_len || clid_len > 130)
 995                 goto out;
 996
 997         update(iface);
 998
 999         struct dhcpv6_assignment *first = NULL;
1000         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1001                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1002                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1003                 bool ia_addr_present = false;
1004                 if (!is_pd && !is_na)
1005                         continue;
1006
1007                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1008                 size_t ia_response_len = 0;
1009                 uint8_t reqlen = (is_pd) ? 62 : 128;
1010                 uint32_t reqhint = 0;
1011
1012                 // Parse request hint for IA-PD
1013                 if (is_pd) {
1014                         uint8_t *sdata;
1015                         uint16_t stype, slen;
1016                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1017                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1018                                         continue;
1019
1020                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1021                                 if (p->prefix) {
1022                                         reqlen = p->prefix;
1023                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1024                                         if (reqlen > 32 && reqlen <= 64)
1025                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1026                                 }
1027                         }
1028
1029                         if (reqlen > 64)
1030                                 reqlen = 64;
1031                 } else if (is_na) {
1032                         uint8_t *sdata;
1033                         uint16_t stype, slen;
1034                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1035                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1036                                         continue;
1037
1038                                 ia_addr_present = true;
1039                         }
1040                 }
1041
1042                 // Find assignment
1043                 struct dhcpv6_assignment *c, *a = NULL;
1044                 list_for_each_entry(c, &iface->ia_assignments, head) {
1045                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1046                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1047                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1048                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1049                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1050                                 a = c;
1051
1052                                 // Reset state
1053                                 apply_lease(iface, a, false);
1054                                 memcpy(a->clid_data, clid_data, clid_len);
1055                                 a->clid_len = clid_len;
1056                                 a->iaid = ia->iaid;
1057                                 a->peer = *addr;
1058                                 a->reconf_cnt = 0;
1059                                 a->reconf_sent = 0;
1060                                 break;
1061                         }
1062                 }
1063
1064                 // Generic message handling
1065                 uint16_t status = DHCPV6_STATUS_OK;
1066                 if (a && a->managed_size < 0) {
1067                         return -1;
1068                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1069                         bool assigned = !!a;
1070
1071                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1072                                 a = calloc(1, sizeof(*a) + clid_len);
1073                                 if (a) {
1074                                         a->clid_len = clid_len;
1075                                         a->iaid = ia->iaid;
1076                                         a->length = reqlen;
1077                                         a->peer = *addr;
1078                                         a->assigned = reqhint;
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->valid_until = 0;
1132                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1133                                 if (hostname_len > 0) {
1134                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1135                                         if (a->hostname) {
1136                                                 memcpy(a->hostname, hostname, hostname_len);
1137                                                 a->hostname[hostname_len] = 0;
1138                                         }
1139                                 }
1140                                 a->accept_reconf = accept_reconf;
1141                                 apply_lease(iface, a, true);
1142                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1143                                 free_dhcpv6_assignment(a);
1144                         }
1145                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1146                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1147                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1148                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1149                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1150                                 status = DHCPV6_STATUS_NOBINDING;
1151                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1152                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1153                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1154                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1155                                 if (a)
1156                                         apply_lease(iface, a, true);
1157                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1158                                 a->valid_until = 0;
1159                                 apply_lease(iface, a, false);
1160                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1161                                 a->clid_len = 0;
1162                                 a->valid_until = now + 3600; // Block address for 1h
1163                         }
1164                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1165                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1166                         status = DHCPV6_STATUS_NOTONLINK;
1167                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1168                         notonlink = true;
1169                 }
1170
1171                 buf += ia_response_len;
1172                 buflen -= ia_response_len;
1173                 response_len += ia_response_len;
1174                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1175         }
1176
1177         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1178                         response_len + 6 < buflen) {
1179                 buf[0] = 0;
1180                 buf[1] = DHCPV6_OPT_STATUS;
1181                 buf[2] = 0;
1182                 buf[3] = 2;
1183                 buf[4] = 0;
1184                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1185                 response_len += 6;
1186         }
1187
1188         dhcpv6_write_statefile();
1189
1190 out:
1191         return response_len;
1192 }