src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19 #include "libubox/usock.h"
  20
  21 #include <time.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <stdio.h>
  25 #include <alloca.h>
  26 #include <resolv.h>
  27 #include <limits.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <unistd.h>
  31 #include <stdbool.h>
  32 #include <arpa/inet.h>
  33 #include <sys/timerfd.h>
  34
  35
  36 static void update(struct interface *iface);
  37 static void reconf_timer(struct uloop_timeout *event);
  38 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  39 static uint32_t serial = 0;
  40 static uint8_t statemd5[16];
  41
  42
  43 int dhcpv6_ia_init(void)
  44 {
  45         uloop_timeout_set(&reconf_event, 2000);
  46         return 0;
  47 }
  48
  49
  50 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  51 {
  52         if (c->managed_sock.fd.registered) {
  53                 close(c->managed_sock.fd.fd);
  54                 ustream_free(&c->managed_sock.stream);
  55         }
  56
  57         free(c->managed);
  58         free(c->hostname);
  59         free(c->classes);
  60         free(c);
  61 }
  62
  63
  64 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  65 {
  66         if (!enable && iface->ia_assignments.next) {
  67                 struct dhcpv6_assignment *c;
  68                 while (!list_empty(&iface->ia_assignments)) {
  69                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  70                         list_del(&c->head);
  71                         free_dhcpv6_assignment(c);
  72                 }
  73         }
  74
  75         if (iface->dhcpv6 == RELAYD_SERVER) {
  76                 if (!iface->ia_assignments.next)
  77                         INIT_LIST_HEAD(&iface->ia_assignments);
  78
  79                 if (list_empty(&iface->ia_assignments)) {
  80                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  81                         if (!border) {
  82                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  83                                 return -1;
  84                         }
  85
  86                         border->length = 64;
  87                         list_add(&border->head, &iface->ia_assignments);
  88                 }
  89
  90                 update(iface);
  91
  92                 // Parse static entries
  93                 struct lease *lease;
  94                 list_for_each_entry(lease, &leases, head) {
  95                         // Construct entry
  96                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  97                         if (!a) {
  98                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  99                                         iface->ifname);
 100                                 return -1;
 101                         }
 102
 103                         a->clid_len = lease->duid_len;
 104                         a->length = 128;
 105                         if (lease->hostid) {
 106                                 a->assigned = lease->hostid;
 107                         } else {
 108                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 109                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 110                         }
 111                         odhcpd_urandom(a->key, sizeof(a->key));
 112                         memcpy(a->clid_data, lease->duid, a->clid_len);
 113                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 114
 115                         // Assign to all interfaces
 116                         struct dhcpv6_assignment *c;
 117                         list_for_each_entry(c, &iface->ia_assignments, head) {
 118                                 if (c->length != 128 || c->assigned > a->assigned) {
 119                                         list_add_tail(&a->head, &c->head);
 120                                         break;
 121                                 } else if (c->assigned == a->assigned) {
 122                                         // Already an assignment with that number
 123                                         break;
 124                                 }
 125                         }
 126
 127                         if (a->head.next) {
 128                                 if (lease->hostname[0]) {
 129                                         free(a->hostname);
 130                                         a->hostname = strdup(lease->hostname);
 131                                 }
 132                         } else {
 133                                 free(a->classes);
 134                                 free(a->hostname);
 135                                 free(a);
 136                         }
 137                 }
 138         }
 139         return 0;
 140 }
 141
 142
 143 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 144 {
 145         struct {
 146                 struct dhcpv6_client_header hdr;
 147                 uint16_t srvid_type;
 148                 uint16_t srvid_len;
 149                 uint16_t duid_type;
 150                 uint16_t hardware_type;
 151                 uint8_t mac[6];
 152                 uint16_t msg_type;
 153                 uint16_t msg_len;
 154                 uint8_t msg_id;
 155                 struct dhcpv6_auth_reconfigure auth;
 156                 uint16_t clid_type;
 157                 uint16_t clid_len;
 158                 uint8_t clid_data[128];
 159         } __attribute__((packed)) reconf_msg = {
 160                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 161                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 162                 .srvid_len = htons(10),
 163                 .duid_type = htons(3),
 164                 .hardware_type = htons(1),
 165                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 166                 .msg_len = htons(1),
 167                 .msg_id = DHCPV6_MSG_RENEW,
 168                 .auth = {htons(DHCPV6_OPT_AUTH),
 169                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 170                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 171                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 172                 .clid_len = htons(assign->clid_len),
 173                 .clid_data = {0},
 174         };
 175
 176         odhcpd_get_mac(iface, reconf_msg.mac);
 177         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 178         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 179
 180         md5_ctx_t md5;
 181         uint8_t secretbytes[64];
 182         memset(secretbytes, 0, sizeof(secretbytes));
 183         memcpy(secretbytes, assign->key, sizeof(assign->key));
 184
 185         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 186                 secretbytes[i] ^= 0x36;
 187
 188         md5_begin(&md5);
 189         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 190         md5_hash(iov.iov_base, iov.iov_len, &md5);
 191         md5_end(reconf_msg.auth.key, &md5);
 192
 193         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 194                 secretbytes[i] ^= 0x36;
 195                 secretbytes[i] ^= 0x5c;
 196         }
 197
 198         md5_begin(&md5);
 199         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 200         md5_hash(reconf_msg.auth.key, 16, &md5);
 201         md5_end(reconf_msg.auth.key, &md5);
 202
 203         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 204 }
 205
 206
 207 void dhcpv6_write_statefile(void)
 208 {
 209         md5_ctx_t md5;
 210         md5_begin(&md5);
 211
 212         if (config.dhcp_statefile) {
 213                 time_t now = odhcpd_time(), wall_time = time(NULL);
 214                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 215                 if (fd < 0)
 216                         return;
 217
 218                 lockf(fd, F_LOCK, 0);
 219                 ftruncate(fd, 0);
 220
 221                 FILE *fp = fdopen(fd, "w");
 222                 if (!fp) {
 223                         close(fd);
 224                         return;
 225                 }
 226
 227                 struct interface *iface;
 228                 list_for_each_entry(iface, &interfaces, head) {
 229                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 230                                 continue;
 231
 232                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 233                                 struct dhcpv6_assignment *c;
 234                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 235                                         if (c->clid_len == 0 || c->managed_size < 0)
 236                                                 continue;
 237
 238                                         char ipbuf[INET6_ADDRSTRLEN];
 239                                         char leasebuf[512];
 240                                         char duidbuf[264];
 241                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 242
 243                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 244                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 245                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 246                                                         (c->hostname ? c->hostname : "-"),
 247                                                         (unsigned)(c->valid_until > now ?
 248                                                                         (c->valid_until - now + wall_time) : 0),
 249                                                         c->assigned, (unsigned)c->length);
 250
 251                                         struct in6_addr addr;
 252                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 253                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 254
 255                                         for (size_t i = 0; i < addrlen; ++i) {
 256                                                 if (addrs[i].prefix > 96)
 257                                                         continue;
 258
 259                                                 addr = addrs[i].addr;
 260                                                 if (c->length == 128)
 261                                                         addr.s6_addr32[3] = htonl(c->assigned);
 262                                                 else
 263                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 264
 265                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 266
 267                                                 if (c->length == 128 && c->hostname && i == 0) {
 268                                                         fputs(ipbuf, fp);
 269
 270                                                         char b[256];
 271                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 272                                                                         iface->search, b, sizeof(b)) > 0)
 273                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 274
 275                                                         fprintf(fp, "\t%s\n", c->hostname);
 276                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 277                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 278                                                 }
 279
 280                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf,
 281                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 282                                         }
 283                                         leasebuf[l - 1] = '\n';
 284                                         fwrite(leasebuf, 1, l, fp);
 285                                 }
 286                         }
 287
 288                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 289                                 struct dhcpv4_assignment *c;
 290                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 291                                         char ipbuf[INET6_ADDRSTRLEN];
 292                                         char leasebuf[512];
 293                                         char duidbuf[16];
 294                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 295
 296                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 297                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 298                                                         iface->ifname, duidbuf,
 299                                                         (c->hostname ? c->hostname : "-"),
 300                                                         (unsigned)(c->valid_until > now ?
 301                                                                         (c->valid_until - now + wall_time) : 0),
 302                                                         c->addr);
 303
 304                                         struct in_addr addr = {htonl(c->addr)};
 305                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 306
 307                                         if (c->hostname[0]) {
 308                                                 fputs(ipbuf, fp);
 309
 310                                                 char b[256];
 311                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 312                                                                 iface->search, b, sizeof(b)) > 0)
 313                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 314
 315                                                 fprintf(fp, "\t%s\n", c->hostname);
 316                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 317                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 318                                         }
 319
 320                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 321                                         leasebuf[l - 1] = '\n';
 322                                         fwrite(leasebuf, 1, l, fp);
 323                                 }
 324                         }
 325                 }
 326
 327                 fclose(fp);
 328         }
 329
 330         uint8_t newmd5[16];
 331         md5_end(newmd5, &md5);
 332
 333         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 334                 memcpy(statemd5, newmd5, sizeof(statemd5));
 335                 char *argv[2] = {config.dhcp_cb, NULL};
 336                 if (!vfork()) {
 337                         execv(argv[0], argv);
 338                         _exit(128);
 339                 }
 340         }
 341 }
 342
 343
 344 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 345 {
 346         if (a->length > 64 || a->managed_size < 0)
 347                 return;
 348
 349         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 350         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 351
 352         for (size_t i = 0; i < addrlen; ++i) {
 353                 struct in6_addr prefix = addrs[i].addr;
 354                 prefix.s6_addr32[1] |= htonl(a->assigned);
 355                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 356                                 iface, &a->peer.sin6_addr, add);
 357         }
 358 }
 359
 360
 361 // More data was received from TCP connection
 362 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 363 {
 364         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 365         time_t now = odhcpd_time();
 366         bool first = c->managed_size < 0;
 367
 368         for (;;) {
 369                 int pending;
 370                 char *data = ustream_get_read_buf(s, &pending);
 371                 char *end = memmem(data, pending, "\n\n", 2);
 372
 373                 if (!end)
 374                         break;
 375
 376                 end += 2;
 377                 end[-1] = 0;
 378
 379                 c->managed_size = 0;
 380                 if (c->accept_reconf)
 381                         c->reconf_cnt = 1;
 382
 383                 char *saveptr;
 384                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 385                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 386                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 387
 388                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 389                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 390                                 continue;
 391
 392                         x = strtok_r(NULL, ",", &saveptr2);
 393                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 394                                 continue;
 395
 396                         x = strtok_r(NULL, ",", &saveptr2);
 397                         if (sscanf(x, "%u", &n->preferred) < 1)
 398                                 continue;
 399
 400                         x = strtok_r(NULL, ",", &saveptr2);
 401                         if (sscanf(x, "%u", &n->valid) < 1)
 402                                 continue;
 403
 404                         n->preferred += now;
 405                         n->valid += now;
 406
 407                         ++c->managed_size;
 408                 }
 409
 410                 ustream_consume(s, end - data);
 411         }
 412
 413         if (first && c->managed_size == 0) {
 414                 list_del(&c->head);
 415                 free_dhcpv6_assignment(c);
 416         }
 417 }
 418
 419
 420 // TCP transmission has ended, either because of success or timeout or other error
 421 static void managed_handle_pd_done(struct ustream *s)
 422 {
 423         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 424         c->valid_until = odhcpd_time() + 15;
 425         c->managed_size = 0;
 426         if (c->accept_reconf)
 427                 c->reconf_cnt = 1;
 428 }
 429
 430
 431
 432 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 433 {
 434         struct dhcpv6_assignment *c;
 435
 436         if (iface->dhcpv6_pd_manager[0]) {
 437                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 438                 if (fd >= 0) {
 439                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 440                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 441                         ustream_fd_init(&assign->managed_sock, fd);
 442                         ustream_printf(&assign->managed_sock.stream, "::/%d,0,0\n\n", assign->length);
 443                         ustream_write_pending(&assign->managed_sock.stream);
 444                         assign->managed_size = -1;
 445                         list_add(&assign->head, &iface->ia_assignments);
 446                 }
 447
 448                 return false;
 449         } else if (iface->ia_addr_len < 1) {
 450                 return false;
 451         }
 452
 453         // Try honoring the hint first
 454         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 455         if (assign->assigned) {
 456                 list_for_each_entry(c, &iface->ia_assignments, head) {
 457                         if (c->length == 128 || c->length == 0)
 458                                 continue;
 459
 460                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 461                                 list_add_tail(&assign->head, &c->head);
 462                                 apply_lease(iface, assign, true);
 463                                 return true;
 464                         }
 465
 466                         if (c->assigned != 0)
 467                                 current = (c->assigned + (1 << (64 - c->length)));
 468                 }
 469         }
 470
 471         // Fallback to a variable assignment
 472         current = 1;
 473         list_for_each_entry(c, &iface->ia_assignments, head) {
 474                 if (c->length == 128 || c->length == 0)
 475                         continue;
 476
 477                 current = (current + asize) & (~asize);
 478                 if (current + asize < c->assigned) {
 479                         assign->assigned = current;
 480                         list_add_tail(&assign->head, &c->head);
 481                         apply_lease(iface, assign, true);
 482                         return true;
 483                 }
 484
 485                 if (c->assigned != 0)
 486                         current = (c->assigned + (1 << (64 - c->length)));
 487         }
 488
 489         return false;
 490 }
 491
 492
 493 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 494 {
 495         bool match = false;
 496         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 497                 if (!iface->ia_addr[i].has_class) {
 498                         match = true;
 499                         continue;
 500                 } else if (assign->classes_cnt) {
 501                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 502                                 if (assign->classes[j] == iface->ia_addr[i].class)
 503                                         match = true;
 504                 } else if (assign->all_class) {
 505                         match = true;
 506                 }
 507         }
 508
 509         if (!match)
 510                 return false;
 511
 512         // Seed RNG with checksum of DUID
 513         uint32_t seed = 0;
 514         for (size_t i = 0; i < assign->clid_len; ++i)
 515                 seed += assign->clid_data[i];
 516         srand(seed);
 517
 518         // Try to assign up to 100x
 519         for (size_t i = 0; i < 100; ++i) {
 520                 uint32_t try;
 521                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 522
 523                 struct dhcpv6_assignment *c;
 524                 list_for_each_entry(c, &iface->ia_assignments, head) {
 525                         if (c->length == 0)
 526                                 continue;
 527
 528                         if (c->assigned > try || c->length != 128) {
 529                                 assign->assigned = try;
 530                                 list_add_tail(&assign->head, &c->head);
 531                                 return true;
 532                         } else if (c->assigned == try) {
 533                                 break;
 534                         }
 535                 }
 536         }
 537
 538         return false;
 539 }
 540
 541
 542 static int prefixcmp(const void *va, const void *vb)
 543 {
 544         const struct odhcpd_ipaddr *a = va, *b = vb;
 545         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 546         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 547         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 548 }
 549
 550
 551 static void update(struct interface *iface)
 552 {
 553         struct odhcpd_ipaddr addr[8];
 554         memset(addr, 0, sizeof(addr));
 555         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 556
 557         if (len < 0)
 558                 return;
 559
 560         qsort(addr, len, sizeof(*addr), prefixcmp);
 561
 562         time_t now = odhcpd_time();
 563         int minprefix = -1;
 564
 565         for (int i = 0; i < len; ++i) {
 566                 if (addr[i].prefix > minprefix)
 567                         minprefix = addr[i].prefix;
 568
 569                 addr[i].addr.s6_addr32[3] = 0;
 570
 571                 if (addr[i].preferred < UINT32_MAX - now)
 572                         addr[i].preferred += now;
 573
 574                 if (addr[i].valid < UINT32_MAX - now)
 575                         addr[i].valid += now;
 576         }
 577
 578         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 579         border->assigned = 1 << (64 - minprefix);
 580
 581         bool change = len != (int)iface->ia_addr_len;
 582         for (int i = 0; !change && i < len; ++i)
 583                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 584                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 585                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 586                                 (addr[i].valid > (uint32_t)now + 7200) !=
 587                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 588                         change = true;
 589
 590         if (change) {
 591                 struct dhcpv6_assignment *c;
 592                 list_for_each_entry(c, &iface->ia_assignments, head)
 593                         if (c != border)
 594                                 apply_lease(iface, c, false);
 595         }
 596
 597         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 598         iface->ia_addr_len = len;
 599
 600         if (change) { // Addresses / prefixes have changed
 601                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 602                 struct dhcpv6_assignment *c, *d;
 603                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 604                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 605                                 continue;
 606
 607                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 608                                 list_move(&c->head, &reassign);
 609                         else if (c != border)
 610                                 apply_lease(iface, c, true);
 611
 612                         if (c->accept_reconf && c->reconf_cnt == 0) {
 613                                 c->reconf_cnt = 1;
 614                                 c->reconf_sent = now;
 615                                 send_reconf(iface, c);
 616
 617                                 // Leave all other assignments of that client alone
 618                                 struct dhcpv6_assignment *a;
 619                                 list_for_each_entry(a, &iface->ia_assignments, head)
 620                                         if (a != c && a->clid_len == c->clid_len &&
 621                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 622                                                 c->reconf_cnt = INT_MAX;
 623                         }
 624                 }
 625
 626                 while (!list_empty(&reassign)) {
 627                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 628                         list_del(&c->head);
 629                         if (!assign_pd(iface, c)) {
 630                                 c->assigned = 0;
 631                                 list_add(&c->head, &iface->ia_assignments);
 632                         }
 633                 }
 634
 635                 dhcpv6_write_statefile();
 636         }
 637 }
 638
 639
 640 static void reconf_timer(struct uloop_timeout *event)
 641 {
 642         time_t now = odhcpd_time();
 643         struct interface *iface;
 644         list_for_each_entry(iface, &interfaces, head) {
 645                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 646                         continue;
 647
 648                 struct dhcpv6_assignment *a, *n;
 649                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 650                         if (a->valid_until < now) {
 651                                 if ((a->length < 128 && a->clid_len > 0) ||
 652                                                 (a->length == 128 && a->clid_len == 0)) {
 653                                         list_del(&a->head);
 654                                         free_dhcpv6_assignment(a);
 655                                 }
 656                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 657                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 658                                 ++a->reconf_cnt;
 659                                 a->reconf_sent = now;
 660                                 send_reconf(iface, a);
 661                         }
 662                 }
 663         }
 664         uloop_timeout_set(event, 2000);
 665 }
 666
 667
 668 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 669                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 670                 struct interface *iface, bool request)
 671 {
 672         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 673                 return 0;
 674
 675         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 676         size_t datalen = sizeof(out);
 677         time_t now = odhcpd_time();
 678
 679         if (status) {
 680                 struct __attribute__((packed)) {
 681                         uint16_t type;
 682                         uint16_t len;
 683                         uint16_t value;
 684                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 685                                 htons(status)};
 686
 687                 memcpy(buf + datalen, &stat, sizeof(stat));
 688                 datalen += sizeof(stat);
 689         } else {
 690                 if (a) {
 691                         uint32_t pref = 3600;
 692                         uint32_t valid = 3600;
 693
 694                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 695                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 696                         for (size_t i = 0; i < addrlen; ++i) {
 697                                 bool match = true;
 698                                 if (addrs[i].has_class) {
 699                                         match = false;
 700                                         if (a->classes_cnt) {
 701                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 702                                                         if (a->classes[j] == addrs[i].class)
 703                                                                 match = true;
 704                                         } else if (a->all_class) {
 705                                                 match = true;
 706                                         }
 707                                 }
 708
 709                                 if (!match)
 710                                         continue;
 711
 712                                 uint32_t prefix_pref = addrs[i].preferred - now;
 713                                 uint32_t prefix_valid = addrs[i].valid - now;
 714
 715                                 if (addrs[i].prefix > 96 ||
 716                                                 addrs[i].preferred <= (uint32_t)now)
 717                                         continue;
 718
 719                                 if (prefix_pref > 86400)
 720                                         prefix_pref = 86400;
 721
 722                                 if (prefix_valid > 86400)
 723                                         prefix_valid = 86400;
 724
 725 #ifdef DHCPV6_OPT_PREFIX_CLASS
 726                                 struct {
 727                                         uint16_t code;
 728                                         uint16_t length;
 729                                         uint16_t class;
 730                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 731                                         htons(2), htons(iface->ia_addr[i].class)};
 732 #endif
 733
 734                                 if (a->length < 128) {
 735                                         struct dhcpv6_ia_prefix p = {
 736                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 737                                                 .len = htons(sizeof(p) - 4),
 738                                                 .preferred = htonl(prefix_pref),
 739                                                 .valid = htonl(prefix_valid),
 740                                                 .prefix = (a->managed_size) ? a->managed_size : a->length,
 741                                                 .addr = addrs[i].addr
 742                                         };
 743                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 744
 745                                         size_t entrlen = sizeof(p) - 4;
 746
 747 #ifdef DHCPV6_OPT_PREFIX_CLASS
 748                                         if (iface->ia_addr[i].has_class) {
 749                                                 entrlen += sizeof(pclass);
 750                                                 p.len = htons(entrlen);
 751                                         }
 752 #endif
 753
 754                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 755                                                 continue;
 756
 757                                         memcpy(buf + datalen, &p, sizeof(p));
 758 #ifdef DHCPV6_OPT_PREFIX_CLASS
 759                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 760 #endif
 761                                         datalen += entrlen + 4;
 762                                 } else {
 763                                         struct dhcpv6_ia_addr n = {
 764                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 765                                                 .len = htons(sizeof(n) - 4),
 766                                                 .addr = addrs[i].addr,
 767                                                 .preferred = htonl(prefix_pref),
 768                                                 .valid = htonl(prefix_valid)
 769                                         };
 770                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 771                                         size_t entrlen = sizeof(n) - 4;
 772
 773 #ifdef DHCPV6_OPT_PREFIX_CLASS
 774                                         if (iface->ia_addr[i].has_class) {
 775                                                 entrlen += sizeof(pclass);
 776                                                 n.len = htons(entrlen);
 777                                         }
 778 #endif
 779
 780                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 781                                                 continue;
 782
 783                                         memcpy(buf + datalen, &n, sizeof(n));
 784 #ifdef DHCPV6_OPT_PREFIX_CLASS
 785                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 786 #endif
 787                                         datalen += entrlen + 4;
 788                                 }
 789
 790                                 // Calculate T1 / T2 based on non-deprecated addresses
 791                                 if (prefix_pref > 0) {
 792                                         if (prefix_pref < pref)
 793                                                 pref = prefix_pref;
 794
 795                                         if (prefix_valid < valid)
 796                                                 valid = prefix_valid;
 797                                 }
 798                         }
 799
 800                         a->valid_until = valid + now;
 801                         out.t1 = htonl(pref * 5 / 10);
 802                         out.t2 = htonl(pref * 8 / 10);
 803
 804                         if (!out.t1)
 805                                 out.t1 = htonl(1);
 806
 807                         if (!out.t2)
 808                                 out.t2 = htonl(1);
 809                 }
 810
 811                 if (!request) {
 812                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 813                         uint16_t otype, olen;
 814                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 815                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 816                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 817                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 818                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 819                                         continue;
 820
 821                                 bool found = false;
 822                                 if (a) {
 823                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 824                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 825
 826                                         for (size_t i = 0; i < addrlen; ++i) {
 827                                                 if (addrs[i].prefix > 96 ||
 828                                                                 addrs[i].preferred <= (uint32_t)now)
 829                                                         continue;
 830
 831                                                 struct in6_addr addr = addrs[i].addr;
 832                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 833                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 834
 835                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 836                                                                         p->prefix == a->length)
 837                                                                 found = true;
 838                                                 } else {
 839                                                         addr.s6_addr32[3] = htonl(a->assigned);
 840
 841                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 842                                                                 found = true;
 843                                                 }
 844                                         }
 845                                 }
 846
 847                                 if (!found) {
 848                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 849                                                 struct dhcpv6_ia_prefix inv = {
 850                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 851                                                         .len = htons(sizeof(inv) - 4),
 852                                                         .preferred = 0,
 853                                                         .valid = 0,
 854                                                         .prefix = p->prefix,
 855                                                         .addr = p->addr
 856                                                 };
 857
 858                                                 if (datalen + sizeof(inv) > buflen)
 859                                                         continue;
 860
 861                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 862                                                 datalen += sizeof(inv);
 863                                         } else {
 864                                                 struct dhcpv6_ia_addr inv = {
 865                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 866                                                         .len = htons(sizeof(inv) - 4),
 867                                                         .addr = n->addr,
 868                                                         .preferred = 0,
 869                                                         .valid = 0
 870                                                 };
 871
 872                                                 if (datalen + sizeof(inv) > buflen)
 873                                                         continue;
 874
 875                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 876                                                 datalen += sizeof(inv);
 877                                         }
 878                                 }
 879                         }
 880                 }
 881         }
 882
 883         out.len = htons(datalen - 4);
 884         memcpy(buf, &out, sizeof(out));
 885         return datalen;
 886 }
 887
 888
 889 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 890                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 891 {
 892         time_t now = odhcpd_time();
 893         size_t response_len = 0;
 894         const struct dhcpv6_client_header *hdr = data;
 895         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 896         uint16_t otype, olen;
 897
 898         // Find and parse client-id and hostname
 899         bool accept_reconf = false;
 900         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 901         char hostname[256];
 902         size_t hostname_len = 0;
 903         bool class_oro = false;
 904         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 905                 if (otype == DHCPV6_OPT_CLIENTID) {
 906                         clid_data = odata;
 907                         clid_len = olen;
 908
 909                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 910                                 memcpy(mac, &odata[8], sizeof(mac));
 911                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 912                                 memcpy(mac, &odata[4], sizeof(mac));
 913                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 914                         uint8_t fqdn_buf[256];
 915                         memcpy(fqdn_buf, odata, olen);
 916                         fqdn_buf[olen++] = 0;
 917
 918                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 919                                 hostname_len = strcspn(hostname, ".");
 920                 } else if (otype == DHCPV6_OPT_ORO) {
 921 #ifdef DHCPV6_OPT_PREFIX_CLASS
 922                         for (size_t i = 0; i + 1 < olen; i += 2) {
 923                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 924                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 925                                         class_oro = true;
 926                         }
 927 #endif
 928                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 929                         accept_reconf = true;
 930                 }
 931         }
 932
 933         if (!clid_data || !clid_len || clid_len > 130)
 934                 goto out;
 935
 936         update(iface);
 937         bool update_state = false;
 938         bool managed_pd_out = false;
 939
 940         struct dhcpv6_assignment *first = NULL;
 941         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 942                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 943                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 944                 if (!is_pd && !is_na)
 945                         continue;
 946
 947                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 948                 size_t ia_response_len = 0;
 949                 uint8_t reqlen = (is_pd) ? 62 : 128;
 950                 uint32_t reqhint = 0;
 951
 952                 const uint8_t classes_max = 32;
 953                 uint8_t classes_cnt = 0;
 954                 uint16_t classes[classes_max];
 955
 956                 // Parse request hint for IA-PD
 957                 if (is_pd) {
 958                         uint8_t *sdata;
 959                         uint16_t stype, slen;
 960                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 961                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 962                                         continue;
 963
 964                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 965                                 if (p->prefix) {
 966                                         reqlen = p->prefix;
 967                                         reqhint = ntohl(p->addr.s6_addr32[1]);
 968                                         if (reqlen > 32 && reqlen <= 64)
 969                                                 reqhint &= (1U << (64 - reqlen)) - 1;
 970                                 }
 971
 972 #ifdef DHCPV6_OPT_PREFIX_CLASS
 973                                 uint8_t *xdata;
 974                                 uint16_t xtype, xlen;
 975                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 976                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 977                                                 continue;
 978
 979                                         if (classes_cnt >= classes_max)
 980                                                 continue;
 981
 982                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 983                                 }
 984 #endif
 985                         }
 986
 987                         if (reqlen > 64)
 988                                 reqlen = 64;
 989                 } else if (is_na) {
 990                         uint8_t *sdata;
 991                         uint16_t stype, slen;
 992                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 993                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
 994                                         continue;
 995
 996 #ifdef DHCPV6_OPT_PREFIX_CLASS
 997                                 uint8_t *xdata;
 998                                 uint16_t xtype, xlen;
 999                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
1000                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
1001                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
1002                                                 continue;
1003
1004                                         if (classes_cnt >= classes_max)
1005                                                 continue;
1006
1007                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1008                                 }
1009 #endif
1010                         }
1011                 }
1012
1013                 // Find assignment
1014                 struct dhcpv6_assignment *c, *a = NULL;
1015                 list_for_each_entry(c, &iface->ia_assignments, head) {
1016                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1017                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1018                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1019                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1020                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1021                                 a = c;
1022
1023                                 // Reset state
1024                                 apply_lease(iface, a, false);
1025                                 memcpy(a->clid_data, clid_data, clid_len);
1026                                 a->clid_len = clid_len;
1027                                 a->iaid = ia->iaid;
1028                                 a->peer = *addr;
1029                                 a->reconf_cnt = 0;
1030                                 a->reconf_sent = 0;
1031                                 a->all_class = class_oro;
1032                                 a->classes_cnt = classes_cnt;
1033                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
1034                                 if (a->classes)
1035                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1036                                 break;
1037                         }
1038                 }
1039
1040                 // Generic message handling
1041                 uint16_t status = DHCPV6_STATUS_OK;
1042                 if (a && a->managed_size < 0) {
1043                         managed_pd_out = true;
1044                         status = DHCPV6_STATUS_NOTONLINK;
1045                         ia_response_len = append_reply(buf, buflen, status, ia, NULL, iface, true);
1046                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1047                         bool assigned = !!a;
1048
1049                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1050                                 a = calloc(1, sizeof(*a) + clid_len);
1051                                 if (a) {
1052                                         a->clid_len = clid_len;
1053                                         a->iaid = ia->iaid;
1054                                         a->length = reqlen;
1055                                         a->peer = *addr;
1056                                         a->assigned = reqhint;
1057                                         a->all_class = class_oro;
1058                                         a->classes_cnt = classes_cnt;
1059                                         if (classes_cnt) {
1060                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
1061                                                 if (a->classes)
1062                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1063                                         }
1064
1065                                         if (first)
1066                                                 memcpy(a->key, first->key, sizeof(a->key));
1067                                         else
1068                                                 odhcpd_urandom(a->key, sizeof(a->key));
1069                                         memcpy(a->clid_data, clid_data, clid_len);
1070
1071                                         if (is_pd)
1072                                                 while (!(assigned = assign_pd(iface, a)) &&
1073                                                                 ++a->length <= 64 && !a->managed_size);
1074                                         else
1075                                                 assigned = assign_na(iface, a);
1076
1077                                         if (a->managed_size && !assigned)
1078                                                 managed_pd_out = true;
1079                                 }
1080                         }
1081
1082                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1083                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1084                         } else if (assigned && !first) { //
1085                                 size_t handshake_len = 4;
1086                                 buf[0] = 0;
1087                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1088                                 buf[2] = 0;
1089                                 buf[3] = 0;
1090
1091                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1092                                         struct dhcpv6_auth_reconfigure auth = {
1093                                                 htons(DHCPV6_OPT_AUTH),
1094                                                 htons(sizeof(auth) - 4),
1095                                                 3, 1, 0,
1096                                                 {htonl(time(NULL)), htonl(++serial)},
1097                                                 1,
1098                                                 {0}
1099                                         };
1100                                         memcpy(auth.key, a->key, sizeof(a->key));
1101                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1102                                         handshake_len += sizeof(auth);
1103                                 }
1104
1105                                 buf += handshake_len;
1106                                 buflen -= handshake_len;
1107                                 response_len += handshake_len;
1108
1109                                 first = a;
1110                         }
1111
1112                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1113
1114                         // Was only a solicitation: mark binding for removal
1115                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1116                                 a->valid_until = now + 15;
1117                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1118                                 if (hostname_len > 0) {
1119                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1120                                         if (a->hostname) {
1121                                                 memcpy(a->hostname, hostname, hostname_len);
1122                                                 a->hostname[hostname_len] = 0;
1123                                         }
1124                                 }
1125                                 a->accept_reconf = accept_reconf;
1126                                 apply_lease(iface, a, true);
1127                                 update_state = true;
1128                         } else if (!assigned && a) { // Cleanup failed assignment
1129                                 free_dhcpv6_assignment(a);
1130                         }
1131                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1132                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1133                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1134                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1135                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1136                                 status = DHCPV6_STATUS_NOBINDING;
1137                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1138                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1139                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1140                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1141                                 if (a)
1142                                         apply_lease(iface, a, true);
1143                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1144                                 a->valid_until = 0;
1145                                 apply_lease(iface, a, false);
1146                                 update_state = true;
1147                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1148                                 a->clid_len = 0;
1149                                 a->valid_until = now + 3600; // Block address for 1h
1150                                 update_state = true;
1151                         }
1152                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1153                         // Always send NOTONLINK for CONFIRM so that clients restart connection
1154                         status = DHCPV6_STATUS_NOTONLINK;
1155                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1156                 }
1157
1158                 buf += ia_response_len;
1159                 buflen -= ia_response_len;
1160                 response_len += ia_response_len;
1161         }
1162
1163         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1164                 buf[0] = 0;
1165                 buf[1] = DHCPV6_OPT_STATUS;
1166                 buf[2] = 0;
1167                 buf[3] = 2;
1168                 buf[4] = 0;
1169                 buf[5] = DHCPV6_STATUS_OK;
1170                 response_len += 6;
1171         } else if (managed_pd_out && response_len + 6 < buflen) {
1172                 buf[0] = 0;
1173                 buf[1] = DHCPV6_OPT_STATUS;
1174                 buf[2] = 0;
1175                 buf[3] = 2;
1176                 buf[4] = 0;
1177                 buf[5] = DHCPV6_STATUS_NOADDRSAVAIL;
1178                 response_len += 6;
1179         }
1180
1181         if (update_state)
1182                 dhcpv6_write_statefile();
1183
1184 out:
1185         return response_len;
1186 }