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                 ustream_free(&c->managed_sock.stream);
  54                 close(c->managed_sock.fd.fd);
  55         }
  56
  57         if (c->head.next)
  58                 list_del(&c->head);
  59
  60         free(c->managed);
  61         free(c->hostname);
  62         free(c->classes);
  63         free(c);
  64 }
  65
  66
  67 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  68 {
  69         if (!enable && iface->ia_assignments.next) {
  70                 struct dhcpv6_assignment *c;
  71                 while (!list_empty(&iface->ia_assignments)) {
  72                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  73                         free_dhcpv6_assignment(c);
  74                 }
  75         }
  76
  77         if (iface->dhcpv6 == RELAYD_SERVER) {
  78                 if (!iface->ia_assignments.next)
  79                         INIT_LIST_HEAD(&iface->ia_assignments);
  80
  81                 if (list_empty(&iface->ia_assignments)) {
  82                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  83                         if (!border) {
  84                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  85                                 return -1;
  86                         }
  87
  88                         border->length = 64;
  89                         list_add(&border->head, &iface->ia_assignments);
  90                 }
  91
  92                 update(iface);
  93
  94                 // Parse static entries
  95                 struct lease *lease;
  96                 list_for_each_entry(lease, &leases, head) {
  97                         // Construct entry
  98                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  99                         if (!a) {
 100                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
 101                                         iface->ifname);
 102                                 return -1;
 103                         }
 104
 105                         a->clid_len = lease->duid_len;
 106                         a->length = 128;
 107                         if (lease->hostid) {
 108                                 a->assigned = lease->hostid;
 109                         } else {
 110                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 111                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 112                         }
 113                         odhcpd_urandom(a->key, sizeof(a->key));
 114                         memcpy(a->clid_data, lease->duid, a->clid_len);
 115                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 116
 117                         // Assign to all interfaces
 118                         struct dhcpv6_assignment *c;
 119                         list_for_each_entry(c, &iface->ia_assignments, head) {
 120                                 if (c->length != 128 || c->assigned > a->assigned) {
 121                                         list_add_tail(&a->head, &c->head);
 122                                         break;
 123                                 } else if (c->assigned == a->assigned) {
 124                                         // Already an assignment with that number
 125                                         break;
 126                                 }
 127                         }
 128
 129                         if (a->head.next) {
 130                                 if (lease->hostname[0]) {
 131                                         free(a->hostname);
 132                                         a->hostname = strdup(lease->hostname);
 133                                 }
 134                         } else {
 135                                 free(a->classes);
 136                                 free(a->hostname);
 137                                 free(a);
 138                         }
 139                 }
 140         }
 141         return 0;
 142 }
 143
 144
 145 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 146 {
 147         struct {
 148                 struct dhcpv6_client_header hdr;
 149                 uint16_t srvid_type;
 150                 uint16_t srvid_len;
 151                 uint16_t duid_type;
 152                 uint16_t hardware_type;
 153                 uint8_t mac[6];
 154                 uint16_t msg_type;
 155                 uint16_t msg_len;
 156                 uint8_t msg_id;
 157                 struct dhcpv6_auth_reconfigure auth;
 158                 uint16_t clid_type;
 159                 uint16_t clid_len;
 160                 uint8_t clid_data[128];
 161         } __attribute__((packed)) reconf_msg = {
 162                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 163                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 164                 .srvid_len = htons(10),
 165                 .duid_type = htons(3),
 166                 .hardware_type = htons(1),
 167                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 168                 .msg_len = htons(1),
 169                 .msg_id = DHCPV6_MSG_RENEW,
 170                 .auth = {htons(DHCPV6_OPT_AUTH),
 171                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 172                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 173                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 174                 .clid_len = htons(assign->clid_len),
 175                 .clid_data = {0},
 176         };
 177
 178         odhcpd_get_mac(iface, reconf_msg.mac);
 179         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 180         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 181
 182         md5_ctx_t md5;
 183         uint8_t secretbytes[64];
 184         memset(secretbytes, 0, sizeof(secretbytes));
 185         memcpy(secretbytes, assign->key, sizeof(assign->key));
 186
 187         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 188                 secretbytes[i] ^= 0x36;
 189
 190         md5_begin(&md5);
 191         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 192         md5_hash(iov.iov_base, iov.iov_len, &md5);
 193         md5_end(reconf_msg.auth.key, &md5);
 194
 195         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 196                 secretbytes[i] ^= 0x36;
 197                 secretbytes[i] ^= 0x5c;
 198         }
 199
 200         md5_begin(&md5);
 201         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 202         md5_hash(reconf_msg.auth.key, 16, &md5);
 203         md5_end(reconf_msg.auth.key, &md5);
 204
 205         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 206 }
 207
 208
 209 void dhcpv6_write_statefile(void)
 210 {
 211         md5_ctx_t md5;
 212         md5_begin(&md5);
 213
 214         if (config.dhcp_statefile) {
 215                 time_t now = odhcpd_time(), wall_time = time(NULL);
 216                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 217                 if (fd < 0)
 218                         return;
 219
 220                 lockf(fd, F_LOCK, 0);
 221                 ftruncate(fd, 0);
 222
 223                 FILE *fp = fdopen(fd, "w");
 224                 if (!fp) {
 225                         close(fd);
 226                         return;
 227                 }
 228
 229                 struct interface *iface;
 230                 list_for_each_entry(iface, &interfaces, head) {
 231                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 232                                 continue;
 233
 234                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 235                                 struct dhcpv6_assignment *c;
 236                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 237                                         if (c->clid_len == 0 || c->managed_size < 0)
 238                                                 continue;
 239
 240                                         char ipbuf[INET6_ADDRSTRLEN];
 241                                         char leasebuf[512];
 242                                         char duidbuf[264];
 243                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 244
 245                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 246                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 247                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 248                                                         (c->hostname ? c->hostname : "-"),
 249                                                         (unsigned)(c->valid_until > now ?
 250                                                                         (c->valid_until - now + wall_time) : 0),
 251                                                         c->assigned, (unsigned)c->length);
 252
 253                                         struct in6_addr addr;
 254                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 255                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 256
 257                                         for (size_t i = 0; i < addrlen; ++i) {
 258                                                 if (addrs[i].prefix > 96)
 259                                                         continue;
 260
 261                                                 addr = addrs[i].addr;
 262                                                 if (c->length == 128)
 263                                                         addr.s6_addr32[3] = htonl(c->assigned);
 264                                                 else
 265                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 266
 267                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 268
 269                                                 if (c->length == 128 && c->hostname && i == 0) {
 270                                                         fputs(ipbuf, fp);
 271
 272                                                         char b[256];
 273                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 274                                                                         iface->search, b, sizeof(b)) > 0)
 275                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 276
 277                                                         fprintf(fp, "\t%s\n", c->hostname);
 278                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 279                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 280                                                 }
 281
 282                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf,
 283                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 284                                         }
 285                                         leasebuf[l - 1] = '\n';
 286                                         fwrite(leasebuf, 1, l, fp);
 287                                 }
 288                         }
 289
 290                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 291                                 struct dhcpv4_assignment *c;
 292                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 293                                         char ipbuf[INET6_ADDRSTRLEN];
 294                                         char leasebuf[512];
 295                                         char duidbuf[16];
 296                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 297
 298                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 299                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 300                                                         iface->ifname, duidbuf,
 301                                                         (c->hostname ? c->hostname : "-"),
 302                                                         (unsigned)(c->valid_until > now ?
 303                                                                         (c->valid_until - now + wall_time) : 0),
 304                                                         c->addr);
 305
 306                                         struct in_addr addr = {htonl(c->addr)};
 307                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 308
 309                                         if (c->hostname[0]) {
 310                                                 fputs(ipbuf, fp);
 311
 312                                                 char b[256];
 313                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 314                                                                 iface->search, b, sizeof(b)) > 0)
 315                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 316
 317                                                 fprintf(fp, "\t%s\n", c->hostname);
 318                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 319                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 320                                         }
 321
 322                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 323                                         leasebuf[l - 1] = '\n';
 324                                         fwrite(leasebuf, 1, l, fp);
 325                                 }
 326                         }
 327                 }
 328
 329                 fclose(fp);
 330         }
 331
 332         uint8_t newmd5[16];
 333         md5_end(newmd5, &md5);
 334
 335         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 336                 memcpy(statemd5, newmd5, sizeof(statemd5));
 337                 char *argv[2] = {config.dhcp_cb, NULL};
 338                 if (!vfork()) {
 339                         execv(argv[0], argv);
 340                         _exit(128);
 341                 }
 342         }
 343 }
 344
 345
 346 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 347 {
 348         if (a->length > 64 || a->managed_size < 0)
 349                 return;
 350
 351         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 352         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 353
 354         for (size_t i = 0; i < addrlen; ++i) {
 355                 struct in6_addr prefix = addrs[i].addr;
 356                 prefix.s6_addr32[1] |= htonl(a->assigned);
 357                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 358                                 iface, &a->peer.sin6_addr, add);
 359         }
 360 }
 361
 362
 363 // More data was received from TCP connection
 364 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 365 {
 366         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 367         time_t now = odhcpd_time();
 368         bool first = c->managed_size < 0;
 369
 370         for (;;) {
 371                 int pending;
 372                 char *data = ustream_get_read_buf(s, &pending);
 373                 char *end = memmem(data, pending, "\n\n", 2);
 374
 375                 if (!end)
 376                         break;
 377
 378                 end += 2;
 379                 end[-1] = 0;
 380
 381                 c->managed_size = 0;
 382                 if (c->accept_reconf)
 383                         c->reconf_cnt = 1;
 384
 385                 char *saveptr;
 386                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 387                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 388                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 389
 390                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 391                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 392                                 continue;
 393
 394                         x = strtok_r(NULL, ",", &saveptr2);
 395                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 396                                 continue;
 397
 398                         x = strtok_r(NULL, ",", &saveptr2);
 399                         if (sscanf(x, "%u", &n->preferred) < 1)
 400                                 continue;
 401
 402                         x = strtok_r(NULL, ",", &saveptr2);
 403                         if (sscanf(x, "%u", &n->valid) < 1)
 404                                 continue;
 405
 406                         if (n->preferred > n->valid)
 407                                 continue;
 408
 409                         if (UINT32_MAX - now < n->preferred)
 410                                 n->preferred = UINT32_MAX;
 411                         else
 412                                 n->preferred += now;
 413
 414                         if (UINT32_MAX - now < n->valid)
 415                                 n->valid = UINT32_MAX;
 416                         else
 417                                 n->valid += now;
 418
 419                         n->has_class = false;
 420                         n->class = 0;
 421                         n->dprefix = 0;
 422
 423                         ++c->managed_size;
 424                 }
 425
 426                 ustream_consume(s, end - data);
 427         }
 428
 429         if (first && c->managed_size == 0)
 430                 free_dhcpv6_assignment(c);
 431 }
 432
 433
 434 // TCP transmission has ended, either because of success or timeout or other error
 435 static void managed_handle_pd_done(struct ustream *s)
 436 {
 437         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 438         c->valid_until = odhcpd_time() + 15;
 439         c->managed_size = 0;
 440         if (c->accept_reconf)
 441                 c->reconf_cnt = 1;
 442 }
 443
 444
 445
 446 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 447 {
 448         struct dhcpv6_assignment *c;
 449
 450         if (iface->dhcpv6_pd_manager[0]) {
 451                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 452                 if (fd >= 0) {
 453                         char iaidbuf[298];
 454                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 455
 456                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 457                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 458                         ustream_fd_init(&assign->managed_sock, fd);
 459                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 460                                         iaidbuf, assign->iaid, assign->length);
 461                         ustream_write_pending(&assign->managed_sock.stream);
 462                         assign->managed_size = -1;
 463                         assign->valid_until = odhcpd_time() + 15;
 464                         list_add(&assign->head, &iface->ia_assignments);
 465                 }
 466
 467                 return false;
 468         } else if (iface->ia_addr_len < 1) {
 469                 return false;
 470         }
 471
 472         // Try honoring the hint first
 473         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 474         if (assign->assigned) {
 475                 list_for_each_entry(c, &iface->ia_assignments, head) {
 476                         if (c->length == 128 || c->length == 0)
 477                                 continue;
 478
 479                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 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
 490         // Fallback to a variable assignment
 491         current = 1;
 492         list_for_each_entry(c, &iface->ia_assignments, head) {
 493                 if (c->length == 128 || c->length == 0)
 494                         continue;
 495
 496                 current = (current + asize) & (~asize);
 497                 if (current + asize < c->assigned) {
 498                         assign->assigned = current;
 499                         list_add_tail(&assign->head, &c->head);
 500                         apply_lease(iface, assign, true);
 501                         return true;
 502                 }
 503
 504                 if (c->assigned != 0)
 505                         current = (c->assigned + (1 << (64 - c->length)));
 506         }
 507
 508         return false;
 509 }
 510
 511
 512 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 513 {
 514         bool match = false;
 515         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 516                 if (!iface->ia_addr[i].has_class) {
 517                         match = true;
 518                         continue;
 519                 } else if (assign->classes_cnt) {
 520                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 521                                 if (assign->classes[j] == iface->ia_addr[i].class)
 522                                         match = true;
 523                 } else if (assign->all_class) {
 524                         match = true;
 525                 }
 526         }
 527
 528         if (!match)
 529                 return false;
 530
 531         // Seed RNG with checksum of DUID
 532         uint32_t seed = 0;
 533         for (size_t i = 0; i < assign->clid_len; ++i)
 534                 seed += assign->clid_data[i];
 535         srand(seed);
 536
 537         // Try to assign up to 100x
 538         for (size_t i = 0; i < 100; ++i) {
 539                 uint32_t try;
 540                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 541
 542                 struct dhcpv6_assignment *c;
 543                 list_for_each_entry(c, &iface->ia_assignments, head) {
 544                         if (c->length == 0)
 545                                 continue;
 546
 547                         if (c->assigned > try || c->length != 128) {
 548                                 assign->assigned = try;
 549                                 list_add_tail(&assign->head, &c->head);
 550                                 return true;
 551                         } else if (c->assigned == try) {
 552                                 break;
 553                         }
 554                 }
 555         }
 556
 557         return false;
 558 }
 559
 560
 561 static int prefixcmp(const void *va, const void *vb)
 562 {
 563         const struct odhcpd_ipaddr *a = va, *b = vb;
 564         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 565         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 566         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 567 }
 568
 569
 570 static void update(struct interface *iface)
 571 {
 572         struct odhcpd_ipaddr addr[8];
 573         memset(addr, 0, sizeof(addr));
 574         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 575
 576         if (len < 0)
 577                 return;
 578
 579         qsort(addr, len, sizeof(*addr), prefixcmp);
 580
 581         time_t now = odhcpd_time();
 582         int minprefix = -1;
 583
 584         for (int i = 0; i < len; ++i) {
 585                 if (addr[i].prefix > minprefix)
 586                         minprefix = addr[i].prefix;
 587
 588                 addr[i].addr.s6_addr32[3] = 0;
 589
 590                 if (addr[i].preferred < UINT32_MAX - now)
 591                         addr[i].preferred += now;
 592
 593                 if (addr[i].valid < UINT32_MAX - now)
 594                         addr[i].valid += now;
 595         }
 596
 597         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 598         border->assigned = 1 << (64 - minprefix);
 599
 600         bool change = len != (int)iface->ia_addr_len;
 601         for (int i = 0; !change && i < len; ++i)
 602                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 603                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 604                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 605                                 (addr[i].valid > (uint32_t)now + 7200) !=
 606                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 607                         change = true;
 608
 609         if (change) {
 610                 struct dhcpv6_assignment *c;
 611                 list_for_each_entry(c, &iface->ia_assignments, head)
 612                         if (c != border)
 613                                 apply_lease(iface, c, false);
 614         }
 615
 616         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 617         iface->ia_addr_len = len;
 618
 619         if (change) { // Addresses / prefixes have changed
 620                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 621                 struct dhcpv6_assignment *c, *d;
 622                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 623                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 624                                 continue;
 625
 626                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 627                                 list_move(&c->head, &reassign);
 628                         else if (c != border)
 629                                 apply_lease(iface, c, true);
 630
 631                         if (c->accept_reconf && c->reconf_cnt == 0) {
 632                                 c->reconf_cnt = 1;
 633                                 c->reconf_sent = now;
 634                                 send_reconf(iface, c);
 635
 636                                 // Leave all other assignments of that client alone
 637                                 struct dhcpv6_assignment *a;
 638                                 list_for_each_entry(a, &iface->ia_assignments, head)
 639                                         if (a != c && a->clid_len == c->clid_len &&
 640                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 641                                                 c->reconf_cnt = INT_MAX;
 642                         }
 643                 }
 644
 645                 while (!list_empty(&reassign)) {
 646                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 647                         list_del(&c->head);
 648                         if (!assign_pd(iface, c)) {
 649                                 c->assigned = 0;
 650                                 list_add(&c->head, &iface->ia_assignments);
 651                         }
 652                 }
 653
 654                 dhcpv6_write_statefile();
 655         }
 656 }
 657
 658
 659 static void reconf_timer(struct uloop_timeout *event)
 660 {
 661         time_t now = odhcpd_time();
 662         struct interface *iface;
 663         list_for_each_entry(iface, &interfaces, head) {
 664                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 665                         continue;
 666
 667                 struct dhcpv6_assignment *a, *n;
 668                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 669                         if (a->valid_until < now) {
 670                                 if ((a->length < 128 && a->clid_len > 0) ||
 671                                                 (a->length == 128 && a->clid_len == 0)) {
 672                                         list_del(&a->head);
 673                                         free_dhcpv6_assignment(a);
 674                                 }
 675                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 676                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 677                                 ++a->reconf_cnt;
 678                                 a->reconf_sent = now;
 679                                 send_reconf(iface, a);
 680                         }
 681                 }
 682         }
 683         uloop_timeout_set(event, 2000);
 684 }
 685
 686
 687 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 688                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 689                 struct interface *iface, bool request)
 690 {
 691         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 692                 return 0;
 693
 694         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 695         size_t datalen = sizeof(out);
 696         time_t now = odhcpd_time();
 697
 698         if (status) {
 699                 struct __attribute__((packed)) {
 700                         uint16_t type;
 701                         uint16_t len;
 702                         uint16_t value;
 703                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 704                                 htons(status)};
 705
 706                 memcpy(buf + datalen, &stat, sizeof(stat));
 707                 datalen += sizeof(stat);
 708         } else {
 709                 if (a) {
 710                         uint32_t pref = 3600;
 711                         uint32_t valid = 3600;
 712
 713                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 714                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 715
 716                         for (size_t i = 0; i < addrlen; ++i) {
 717                                 bool match = true;
 718                                 if (addrs[i].has_class) {
 719                                         match = false;
 720                                         if (a->classes_cnt) {
 721                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 722                                                         if (a->classes[j] == addrs[i].class)
 723                                                                 match = true;
 724                                         } else if (a->all_class) {
 725                                                 match = true;
 726                                         }
 727                                 }
 728
 729                                 if (!match)
 730                                         continue;
 731
 732                                 uint32_t prefix_pref = addrs[i].preferred - now;
 733                                 uint32_t prefix_valid = addrs[i].valid - now;
 734
 735                                 if (addrs[i].prefix > 96 ||
 736                                                 addrs[i].preferred <= (uint32_t)now)
 737                                         continue;
 738
 739                                 if (prefix_pref > 86400)
 740                                         prefix_pref = 86400;
 741
 742                                 if (prefix_valid > 86400)
 743                                         prefix_valid = 86400;
 744
 745 #ifdef DHCPV6_OPT_PREFIX_CLASS
 746                                 struct {
 747                                         uint16_t code;
 748                                         uint16_t length;
 749                                         uint16_t class;
 750                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 751                                         htons(2), htons(iface->ia_addr[i].class)};
 752 #endif
 753
 754                                 if (a->length < 128) {
 755                                         struct dhcpv6_ia_prefix p = {
 756                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 757                                                 .len = htons(sizeof(p) - 4),
 758                                                 .preferred = htonl(prefix_pref),
 759                                                 .valid = htonl(prefix_valid),
 760                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 761                                                 .addr = addrs[i].addr
 762                                         };
 763                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 764
 765                                         size_t entrlen = sizeof(p) - 4;
 766
 767 #ifdef DHCPV6_OPT_PREFIX_CLASS
 768                                         if (iface->ia_addr[i].has_class) {
 769                                                 entrlen += sizeof(pclass);
 770                                                 p.len = htons(entrlen);
 771                                         }
 772 #endif
 773
 774                                         if (datalen + entrlen + 4 > buflen ||
 775                                                         (a->assigned == 0 && a->managed_size == 0))
 776                                                 continue;
 777
 778                                         memcpy(buf + datalen, &p, sizeof(p));
 779 #ifdef DHCPV6_OPT_PREFIX_CLASS
 780                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 781 #endif
 782                                         datalen += entrlen + 4;
 783                                 } else {
 784                                         struct dhcpv6_ia_addr n = {
 785                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 786                                                 .len = htons(sizeof(n) - 4),
 787                                                 .addr = addrs[i].addr,
 788                                                 .preferred = htonl(prefix_pref),
 789                                                 .valid = htonl(prefix_valid)
 790                                         };
 791                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 792                                         size_t entrlen = sizeof(n) - 4;
 793
 794 #ifdef DHCPV6_OPT_PREFIX_CLASS
 795                                         if (iface->ia_addr[i].has_class) {
 796                                                 entrlen += sizeof(pclass);
 797                                                 n.len = htons(entrlen);
 798                                         }
 799 #endif
 800
 801                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 802                                                 continue;
 803
 804                                         memcpy(buf + datalen, &n, sizeof(n));
 805 #ifdef DHCPV6_OPT_PREFIX_CLASS
 806                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 807 #endif
 808                                         datalen += entrlen + 4;
 809                                 }
 810
 811                                 // Calculate T1 / T2 based on non-deprecated addresses
 812                                 if (prefix_pref > 0) {
 813                                         if (prefix_pref < pref)
 814                                                 pref = prefix_pref;
 815
 816                                         if (prefix_valid < valid)
 817                                                 valid = prefix_valid;
 818                                 }
 819                         }
 820
 821                         a->valid_until = valid + now;
 822                         out.t1 = htonl(pref * 5 / 10);
 823                         out.t2 = htonl(pref * 8 / 10);
 824
 825                         if (!out.t1)
 826                                 out.t1 = htonl(1);
 827
 828                         if (!out.t2)
 829                                 out.t2 = htonl(1);
 830                 }
 831
 832                 if (!request) {
 833                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 834                         uint16_t otype, olen;
 835                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 836                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 837                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 838                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 839                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 840                                         continue;
 841
 842                                 bool found = false;
 843                                 if (a) {
 844                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 845                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 846
 847                                         for (size_t i = 0; i < addrlen; ++i) {
 848                                                 if (addrs[i].prefix > 96 ||
 849                                                                 addrs[i].preferred <= (uint32_t)now)
 850                                                         continue;
 851
 852                                                 struct in6_addr addr = addrs[i].addr;
 853                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 854                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 855
 856                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 857                                                                         p->prefix == a->length)
 858                                                                 found = true;
 859                                                 } else {
 860                                                         addr.s6_addr32[3] = htonl(a->assigned);
 861
 862                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 863                                                                 found = true;
 864                                                 }
 865                                         }
 866                                 }
 867
 868                                 if (!found) {
 869                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 870                                                 struct dhcpv6_ia_prefix inv = {
 871                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 872                                                         .len = htons(sizeof(inv) - 4),
 873                                                         .preferred = 0,
 874                                                         .valid = 0,
 875                                                         .prefix = p->prefix,
 876                                                         .addr = p->addr
 877                                                 };
 878
 879                                                 if (datalen + sizeof(inv) > buflen)
 880                                                         continue;
 881
 882                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 883                                                 datalen += sizeof(inv);
 884                                         } else {
 885                                                 struct dhcpv6_ia_addr inv = {
 886                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 887                                                         .len = htons(sizeof(inv) - 4),
 888                                                         .addr = n->addr,
 889                                                         .preferred = 0,
 890                                                         .valid = 0
 891                                                 };
 892
 893                                                 if (datalen + sizeof(inv) > buflen)
 894                                                         continue;
 895
 896                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 897                                                 datalen += sizeof(inv);
 898                                         }
 899                                 }
 900                         }
 901                 }
 902         }
 903
 904         out.len = htons(datalen - 4);
 905         memcpy(buf, &out, sizeof(out));
 906         return datalen;
 907 }
 908
 909
 910 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 911                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 912 {
 913         time_t now = odhcpd_time();
 914         size_t response_len = 0;
 915         const struct dhcpv6_client_header *hdr = data;
 916         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 917         uint16_t otype, olen;
 918
 919         // Find and parse client-id and hostname
 920         bool accept_reconf = false;
 921         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 922         char hostname[256];
 923         size_t hostname_len = 0;
 924         bool class_oro = false;
 925         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 926                 if (otype == DHCPV6_OPT_CLIENTID) {
 927                         clid_data = odata;
 928                         clid_len = olen;
 929
 930                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 931                                 memcpy(mac, &odata[8], sizeof(mac));
 932                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 933                                 memcpy(mac, &odata[4], sizeof(mac));
 934                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 935                         uint8_t fqdn_buf[256];
 936                         memcpy(fqdn_buf, odata, olen);
 937                         fqdn_buf[olen++] = 0;
 938
 939                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 940                                 hostname_len = strcspn(hostname, ".");
 941                 } else if (otype == DHCPV6_OPT_ORO) {
 942 #ifdef DHCPV6_OPT_PREFIX_CLASS
 943                         for (size_t i = 0; i + 1 < olen; i += 2) {
 944                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 945                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 946                                         class_oro = true;
 947                         }
 948 #endif
 949                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 950                         accept_reconf = true;
 951                 }
 952         }
 953
 954         if (!clid_data || !clid_len || clid_len > 130)
 955                 goto out;
 956
 957         update(iface);
 958         bool update_state = false;
 959
 960         struct dhcpv6_assignment *first = NULL;
 961         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 962                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 963                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 964                 if (!is_pd && !is_na)
 965                         continue;
 966
 967                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 968                 size_t ia_response_len = 0;
 969                 uint8_t reqlen = (is_pd) ? 62 : 128;
 970                 uint32_t reqhint = 0;
 971
 972                 const uint8_t classes_max = 32;
 973                 uint8_t classes_cnt = 0;
 974                 uint16_t classes[classes_max];
 975
 976                 // Parse request hint for IA-PD
 977                 if (is_pd) {
 978                         uint8_t *sdata;
 979                         uint16_t stype, slen;
 980                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 981                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 982                                         continue;
 983
 984                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 985                                 if (p->prefix) {
 986                                         reqlen = p->prefix;
 987                                         reqhint = ntohl(p->addr.s6_addr32[1]);
 988                                         if (reqlen > 32 && reqlen <= 64)
 989                                                 reqhint &= (1U << (64 - reqlen)) - 1;
 990                                 }
 991
 992 #ifdef DHCPV6_OPT_PREFIX_CLASS
 993                                 uint8_t *xdata;
 994                                 uint16_t xtype, xlen;
 995                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 996                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 997                                                 continue;
 998
 999                                         if (classes_cnt >= classes_max)
1000                                                 continue;
1001
1002                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1003                                 }
1004 #endif
1005                         }
1006
1007                         if (reqlen > 64)
1008                                 reqlen = 64;
1009                 } else if (is_na) {
1010                         uint8_t *sdata;
1011                         uint16_t stype, slen;
1012                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1013                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1014                                         continue;
1015
1016 #ifdef DHCPV6_OPT_PREFIX_CLASS
1017                                 uint8_t *xdata;
1018                                 uint16_t xtype, xlen;
1019                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
1020                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
1021                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
1022                                                 continue;
1023
1024                                         if (classes_cnt >= classes_max)
1025                                                 continue;
1026
1027                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1028                                 }
1029 #endif
1030                         }
1031                 }
1032
1033                 // Find assignment
1034                 struct dhcpv6_assignment *c, *a = NULL;
1035                 list_for_each_entry(c, &iface->ia_assignments, head) {
1036                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1037                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1038                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1039                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1040                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1041                                 a = c;
1042
1043                                 // Reset state
1044                                 apply_lease(iface, a, false);
1045                                 memcpy(a->clid_data, clid_data, clid_len);
1046                                 a->clid_len = clid_len;
1047                                 a->iaid = ia->iaid;
1048                                 a->peer = *addr;
1049                                 a->reconf_cnt = 0;
1050                                 a->reconf_sent = 0;
1051                                 a->all_class = class_oro;
1052                                 a->classes_cnt = classes_cnt;
1053                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
1054                                 if (a->classes)
1055                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1056                                 break;
1057                         }
1058                 }
1059
1060                 // Generic message handling
1061                 uint16_t status = DHCPV6_STATUS_OK;
1062                 if (a && a->managed_size < 0) {
1063                         return -1;
1064                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1065                         bool assigned = !!a;
1066
1067                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1068                                 a = calloc(1, sizeof(*a) + clid_len);
1069                                 if (a) {
1070                                         a->clid_len = clid_len;
1071                                         a->iaid = ia->iaid;
1072                                         a->length = reqlen;
1073                                         a->peer = *addr;
1074                                         a->assigned = reqhint;
1075                                         a->all_class = class_oro;
1076                                         a->classes_cnt = classes_cnt;
1077                                         if (classes_cnt) {
1078                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
1079                                                 if (a->classes)
1080                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1081                                         }
1082
1083                                         if (first)
1084                                                 memcpy(a->key, first->key, sizeof(a->key));
1085                                         else
1086                                                 odhcpd_urandom(a->key, sizeof(a->key));
1087                                         memcpy(a->clid_data, clid_data, clid_len);
1088
1089                                         if (is_pd)
1090                                                 while (!(assigned = assign_pd(iface, a)) &&
1091                                                                 !a->managed_size && ++a->length <= 64);
1092                                         else
1093                                                 assigned = assign_na(iface, a);
1094
1095                                         if (a->managed_size && !assigned)
1096                                                 return -1;
1097                                 }
1098                         }
1099
1100                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1101                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1102                         } else if (assigned && !first) { //
1103                                 size_t handshake_len = 4;
1104                                 buf[0] = 0;
1105                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1106                                 buf[2] = 0;
1107                                 buf[3] = 0;
1108
1109                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1110                                         struct dhcpv6_auth_reconfigure auth = {
1111                                                 htons(DHCPV6_OPT_AUTH),
1112                                                 htons(sizeof(auth) - 4),
1113                                                 3, 1, 0,
1114                                                 {htonl(time(NULL)), htonl(++serial)},
1115                                                 1,
1116                                                 {0}
1117                                         };
1118                                         memcpy(auth.key, a->key, sizeof(a->key));
1119                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1120                                         handshake_len += sizeof(auth);
1121                                 }
1122
1123                                 buf += handshake_len;
1124                                 buflen -= handshake_len;
1125                                 response_len += handshake_len;
1126
1127                                 first = a;
1128                         }
1129
1130                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1131
1132                         // Was only a solicitation: mark binding for removal
1133                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1134                                 a->valid_until = 0;
1135                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1136                                 if (hostname_len > 0) {
1137                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1138                                         if (a->hostname) {
1139                                                 memcpy(a->hostname, hostname, hostname_len);
1140                                                 a->hostname[hostname_len] = 0;
1141                                         }
1142                                 }
1143                                 a->accept_reconf = accept_reconf;
1144                                 apply_lease(iface, a, true);
1145                                 update_state = true;
1146                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1147                                 free_dhcpv6_assignment(a);
1148                         }
1149                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1150                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1151                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1152                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1153                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1154                                 status = DHCPV6_STATUS_NOBINDING;
1155                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1156                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1157                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1158                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1159                                 if (a)
1160                                         apply_lease(iface, a, true);
1161                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1162                                 a->valid_until = 0;
1163                                 apply_lease(iface, a, false);
1164                                 update_state = true;
1165                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1166                                 a->clid_len = 0;
1167                                 a->valid_until = now + 3600; // Block address for 1h
1168                                 update_state = true;
1169                         }
1170                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1171                         // Always send NOTONLINK for CONFIRM so that clients restart connection
1172                         status = DHCPV6_STATUS_NOTONLINK;
1173                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1174                 }
1175
1176                 buf += ia_response_len;
1177                 buflen -= ia_response_len;
1178                 response_len += ia_response_len;
1179         }
1180
1181         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1182                 buf[0] = 0;
1183                 buf[1] = DHCPV6_OPT_STATUS;
1184                 buf[2] = 0;
1185                 buf[3] = 2;
1186                 buf[4] = 0;
1187                 buf[5] = DHCPV6_STATUS_OK;
1188                 response_len += 6;
1189         }
1190
1191         if (update_state)
1192                 dhcpv6_write_statefile();
1193
1194 out:
1195         return response_len;
1196 }