src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19 #include "libubox/usock.h"
  20
  21 #include <time.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <stdio.h>
  25 #include <poll.h>
  26 #include <alloca.h>
  27 #include <resolv.h>
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <stdbool.h>
  33 #include <arpa/inet.h>
  34 #include <sys/timerfd.h>
  35
  36
  37 static void update(struct interface *iface);
  38 static void reconf_timer(struct uloop_timeout *event);
  39 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  40 static uint32_t serial = 0;
  41 static uint8_t statemd5[16];
  42
  43
  44 int dhcpv6_ia_init(void)
  45 {
  46         uloop_timeout_set(&reconf_event, 2000);
  47         return 0;
  48 }
  49
  50
  51 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  52 {
  53         if (c->managed_sock.fd.registered) {
  54                 ustream_free(&c->managed_sock.stream);
  55                 close(c->managed_sock.fd.fd);
  56         }
  57
  58         if (c->head.next)
  59                 list_del(&c->head);
  60
  61         free(c->managed);
  62         free(c->hostname);
  63         free(c->classes);
  64         free(c);
  65 }
  66
  67
  68 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  69 {
  70         if (!enable && iface->ia_assignments.next) {
  71                 struct dhcpv6_assignment *c;
  72                 while (!list_empty(&iface->ia_assignments)) {
  73                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  74                         free_dhcpv6_assignment(c);
  75                 }
  76         }
  77
  78         if (iface->dhcpv6 == RELAYD_SERVER) {
  79                 if (!iface->ia_assignments.next)
  80                         INIT_LIST_HEAD(&iface->ia_assignments);
  81
  82                 if (list_empty(&iface->ia_assignments)) {
  83                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  84                         if (!border) {
  85                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  86                                 return -1;
  87                         }
  88
  89                         border->length = 64;
  90                         list_add(&border->head, &iface->ia_assignments);
  91                 }
  92
  93                 update(iface);
  94
  95                 // Parse static entries
  96                 struct lease *lease;
  97                 list_for_each_entry(lease, &leases, head) {
  98                         // Construct entry
  99                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
 100                         if (!a) {
 101                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
 102                                         iface->ifname);
 103                                 return -1;
 104                         }
 105
 106                         a->clid_len = lease->duid_len;
 107                         a->length = 128;
 108                         if (lease->hostid) {
 109                                 a->assigned = lease->hostid;
 110                         } else {
 111                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 112                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 113                         }
 114                         odhcpd_urandom(a->key, sizeof(a->key));
 115                         memcpy(a->clid_data, lease->duid, a->clid_len);
 116                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 117
 118                         // Assign to all interfaces
 119                         struct dhcpv6_assignment *c;
 120                         list_for_each_entry(c, &iface->ia_assignments, head) {
 121                                 if (c->length != 128 || c->assigned > a->assigned) {
 122                                         list_add_tail(&a->head, &c->head);
 123                                         break;
 124                                 } else if (c->assigned == a->assigned) {
 125                                         // Already an assignment with that number
 126                                         break;
 127                                 }
 128                         }
 129
 130                         if (a->head.next) {
 131                                 if (lease->hostname[0]) {
 132                                         free(a->hostname);
 133                                         a->hostname = strdup(lease->hostname);
 134                                 }
 135                         } else {
 136                                 free(a->classes);
 137                                 free(a->hostname);
 138                                 free(a);
 139                         }
 140                 }
 141         }
 142         return 0;
 143 }
 144
 145
 146 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 147 {
 148         struct {
 149                 struct dhcpv6_client_header hdr;
 150                 uint16_t srvid_type;
 151                 uint16_t srvid_len;
 152                 uint16_t duid_type;
 153                 uint16_t hardware_type;
 154                 uint8_t mac[6];
 155                 uint16_t msg_type;
 156                 uint16_t msg_len;
 157                 uint8_t msg_id;
 158                 struct dhcpv6_auth_reconfigure auth;
 159                 uint16_t clid_type;
 160                 uint16_t clid_len;
 161                 uint8_t clid_data[128];
 162         } __attribute__((packed)) reconf_msg = {
 163                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 164                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 165                 .srvid_len = htons(10),
 166                 .duid_type = htons(3),
 167                 .hardware_type = htons(1),
 168                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 169                 .msg_len = htons(1),
 170                 .msg_id = DHCPV6_MSG_RENEW,
 171                 .auth = {htons(DHCPV6_OPT_AUTH),
 172                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 173                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 174                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 175                 .clid_len = htons(assign->clid_len),
 176                 .clid_data = {0},
 177         };
 178
 179         odhcpd_get_mac(iface, reconf_msg.mac);
 180         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 181         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 182
 183         md5_ctx_t md5;
 184         uint8_t secretbytes[64];
 185         memset(secretbytes, 0, sizeof(secretbytes));
 186         memcpy(secretbytes, assign->key, sizeof(assign->key));
 187
 188         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 189                 secretbytes[i] ^= 0x36;
 190
 191         md5_begin(&md5);
 192         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 193         md5_hash(iov.iov_base, iov.iov_len, &md5);
 194         md5_end(reconf_msg.auth.key, &md5);
 195
 196         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 197                 secretbytes[i] ^= 0x36;
 198                 secretbytes[i] ^= 0x5c;
 199         }
 200
 201         md5_begin(&md5);
 202         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 203         md5_hash(reconf_msg.auth.key, 16, &md5);
 204         md5_end(reconf_msg.auth.key, &md5);
 205
 206         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 207 }
 208
 209
 210 void dhcpv6_write_statefile(void)
 211 {
 212         md5_ctx_t md5;
 213         md5_begin(&md5);
 214
 215         if (config.dhcp_statefile) {
 216                 time_t now = odhcpd_time(), wall_time = time(NULL);
 217                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 218                 if (fd < 0)
 219                         return;
 220
 221                 lockf(fd, F_LOCK, 0);
 222                 ftruncate(fd, 0);
 223
 224                 FILE *fp = fdopen(fd, "w");
 225                 if (!fp) {
 226                         close(fd);
 227                         return;
 228                 }
 229
 230                 struct interface *iface;
 231                 list_for_each_entry(iface, &interfaces, head) {
 232                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 233                                 continue;
 234
 235                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 236                                 struct dhcpv6_assignment *c;
 237                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 238                                         if (c->clid_len == 0 || c->managed_size < 0)
 239                                                 continue;
 240
 241                                         char ipbuf[INET6_ADDRSTRLEN];
 242                                         char leasebuf[512];
 243                                         char duidbuf[264];
 244                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 245
 246                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 247                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 248                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 249                                                         (c->hostname ? c->hostname : "-"),
 250                                                         (unsigned)(c->valid_until > now ?
 251                                                                         (c->valid_until - now + wall_time) : 0),
 252                                                         c->assigned, (unsigned)c->length);
 253
 254                                         struct in6_addr addr;
 255                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 256                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 257
 258                                         for (size_t i = 0; i < addrlen; ++i) {
 259                                                 if (addrs[i].prefix > 96)
 260                                                         continue;
 261
 262                                                 addr = addrs[i].addr;
 263                                                 if (c->length == 128)
 264                                                         addr.s6_addr32[3] = htonl(c->assigned);
 265                                                 else
 266                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 267
 268                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 269
 270                                                 if (c->length == 128 && c->hostname && i == 0) {
 271                                                         fputs(ipbuf, fp);
 272
 273                                                         char b[256];
 274                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 275                                                                         iface->search, b, sizeof(b)) > 0)
 276                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 277
 278                                                         fprintf(fp, "\t%s\n", c->hostname);
 279                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 280                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 281                                                 }
 282
 283                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 284                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 285                                         }
 286                                         leasebuf[l - 1] = '\n';
 287                                         fwrite(leasebuf, 1, l, fp);
 288                                 }
 289                         }
 290
 291                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 292                                 struct dhcpv4_assignment *c;
 293                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 294                                         char ipbuf[INET6_ADDRSTRLEN];
 295                                         char leasebuf[512];
 296                                         char duidbuf[16];
 297                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 298
 299                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 300                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 301                                                         iface->ifname, duidbuf,
 302                                                         (c->hostname ? c->hostname : "-"),
 303                                                         (unsigned)(c->valid_until > now ?
 304                                                                         (c->valid_until - now + wall_time) : 0),
 305                                                         c->addr);
 306
 307                                         struct in_addr addr = {htonl(c->addr)};
 308                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 309
 310                                         if (c->hostname[0]) {
 311                                                 fputs(ipbuf, fp);
 312
 313                                                 char b[256];
 314                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 315                                                                 iface->search, b, sizeof(b)) > 0)
 316                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 317
 318                                                 fprintf(fp, "\t%s\n", c->hostname);
 319                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 320                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 321                                         }
 322
 323                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 324                                         leasebuf[l - 1] = '\n';
 325                                         fwrite(leasebuf, 1, l, fp);
 326                                 }
 327                         }
 328                 }
 329
 330                 fclose(fp);
 331         }
 332
 333         uint8_t newmd5[16];
 334         md5_end(newmd5, &md5);
 335
 336         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 337                 memcpy(statemd5, newmd5, sizeof(statemd5));
 338                 char *argv[2] = {config.dhcp_cb, NULL};
 339                 if (!vfork()) {
 340                         execv(argv[0], argv);
 341                         _exit(128);
 342                 }
 343         }
 344 }
 345
 346
 347 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 348 {
 349         if (a->length > 64 || a->managed_size < 0)
 350                 return;
 351
 352         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 353         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 354
 355         for (size_t i = 0; i < addrlen; ++i) {
 356                 struct in6_addr prefix = addrs[i].addr;
 357                 prefix.s6_addr32[1] |= htonl(a->assigned);
 358                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 359                                 iface, &a->peer.sin6_addr, add);
 360         }
 361 }
 362
 363
 364 // More data was received from TCP connection
 365 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 366 {
 367         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 368         time_t now = odhcpd_time();
 369         bool first = c->managed_size < 0;
 370
 371         for (;;) {
 372                 int pending;
 373                 char *data = ustream_get_read_buf(s, &pending);
 374                 char *end = memmem(data, pending, "\n\n", 2);
 375
 376                 if (!end)
 377                         break;
 378
 379                 end += 2;
 380                 end[-1] = 0;
 381
 382                 c->managed_size = 0;
 383                 if (c->accept_reconf)
 384                         c->reconf_cnt = 1;
 385
 386                 char *saveptr;
 387                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 388                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 389                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 390
 391                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 392                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 393                                 continue;
 394
 395                         x = strtok_r(NULL, ",", &saveptr2);
 396                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 397                                 continue;
 398
 399                         x = strtok_r(NULL, ",", &saveptr2);
 400                         if (sscanf(x, "%u", &n->preferred) < 1)
 401                                 continue;
 402
 403                         x = strtok_r(NULL, ",", &saveptr2);
 404                         if (sscanf(x, "%u", &n->valid) < 1)
 405                                 continue;
 406
 407                         if (n->preferred > n->valid)
 408                                 continue;
 409
 410                         if (UINT32_MAX - now < n->preferred)
 411                                 n->preferred = UINT32_MAX;
 412                         else
 413                                 n->preferred += now;
 414
 415                         if (UINT32_MAX - now < n->valid)
 416                                 n->valid = UINT32_MAX;
 417                         else
 418                                 n->valid += now;
 419
 420                         n->has_class = false;
 421                         n->class = 0;
 422                         n->dprefix = 0;
 423
 424                         ++c->managed_size;
 425                 }
 426
 427                 ustream_consume(s, end - data);
 428         }
 429
 430         if (first && c->managed_size == 0)
 431                 free_dhcpv6_assignment(c);
 432         else if (first)
 433                 c->valid_until = now + 150;
 434 }
 435
 436
 437 // TCP transmission has ended, either because of success or timeout or other error
 438 static void managed_handle_pd_done(struct ustream *s)
 439 {
 440         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 441         c->valid_until = odhcpd_time() + 15;
 442         c->managed_size = 0;
 443         if (c->accept_reconf)
 444                 c->reconf_cnt = 1;
 445 }
 446
 447
 448
 449 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 450 {
 451         struct dhcpv6_assignment *c;
 452
 453         if (iface->dhcpv6_pd_manager[0]) {
 454                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 455                 if (fd >= 0) {
 456                         char iaidbuf[298];
 457                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 458
 459                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 460                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 461                         ustream_fd_init(&assign->managed_sock, fd);
 462                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 463                                         iaidbuf, assign->iaid, assign->length);
 464                         ustream_write_pending(&assign->managed_sock.stream);
 465                         assign->managed_size = -1;
 466                         assign->valid_until = odhcpd_time() + 15;
 467                         list_add(&assign->head, &iface->ia_assignments);
 468
 469                         // Wait initial period of up to 250ms for immediate assignment
 470                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 471                         poll(&pfd, 1, 250);
 472                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 473
 474                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 475                                 return true;
 476                 }
 477
 478                 return false;
 479         } else if (iface->ia_addr_len < 1) {
 480                 return false;
 481         }
 482
 483         // Try honoring the hint first
 484         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 485         if (assign->assigned) {
 486                 list_for_each_entry(c, &iface->ia_assignments, head) {
 487                         if (c->length == 128 || c->length == 0)
 488                                 continue;
 489
 490                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 491                                 list_add_tail(&assign->head, &c->head);
 492                                 apply_lease(iface, assign, true);
 493                                 return true;
 494                         }
 495
 496                         if (c->assigned != 0)
 497                                 current = (c->assigned + (1 << (64 - c->length)));
 498                 }
 499         }
 500
 501         // Fallback to a variable assignment
 502         current = 1;
 503         list_for_each_entry(c, &iface->ia_assignments, head) {
 504                 if (c->length == 128 || c->length == 0)
 505                         continue;
 506
 507                 current = (current + asize) & (~asize);
 508                 if (current + asize < c->assigned) {
 509                         assign->assigned = current;
 510                         list_add_tail(&assign->head, &c->head);
 511                         apply_lease(iface, assign, true);
 512                         return true;
 513                 }
 514
 515                 if (c->assigned != 0)
 516                         current = (c->assigned + (1 << (64 - c->length)));
 517         }
 518
 519         return false;
 520 }
 521
 522
 523 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 524 {
 525         bool match = false;
 526         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 527                 if (!iface->ia_addr[i].has_class) {
 528                         match = true;
 529                         continue;
 530                 } else if (assign->classes_cnt) {
 531                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 532                                 if (assign->classes[j] == iface->ia_addr[i].class)
 533                                         match = true;
 534                 } else if (assign->all_class) {
 535                         match = true;
 536                 }
 537         }
 538
 539         if (!match)
 540                 return false;
 541
 542         // Seed RNG with checksum of DUID
 543         uint32_t seed = 0;
 544         for (size_t i = 0; i < assign->clid_len; ++i)
 545                 seed += assign->clid_data[i];
 546         srand(seed);
 547
 548         // Try to assign up to 100x
 549         for (size_t i = 0; i < 100; ++i) {
 550                 uint32_t try;
 551                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 552
 553                 struct dhcpv6_assignment *c;
 554                 list_for_each_entry(c, &iface->ia_assignments, head) {
 555                         if (c->length == 0)
 556                                 continue;
 557
 558                         if (c->assigned > try || c->length != 128) {
 559                                 assign->assigned = try;
 560                                 list_add_tail(&assign->head, &c->head);
 561                                 return true;
 562                         } else if (c->assigned == try) {
 563                                 break;
 564                         }
 565                 }
 566         }
 567
 568         return false;
 569 }
 570
 571
 572 static int prefixcmp(const void *va, const void *vb)
 573 {
 574         const struct odhcpd_ipaddr *a = va, *b = vb;
 575         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 576         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 577         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 578 }
 579
 580
 581 static void update(struct interface *iface)
 582 {
 583         struct odhcpd_ipaddr addr[8];
 584         memset(addr, 0, sizeof(addr));
 585         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 586
 587         if (len < 0)
 588                 return;
 589
 590         qsort(addr, len, sizeof(*addr), prefixcmp);
 591
 592         time_t now = odhcpd_time();
 593         int minprefix = -1;
 594
 595         for (int i = 0; i < len; ++i) {
 596                 if (addr[i].prefix > minprefix)
 597                         minprefix = addr[i].prefix;
 598
 599                 addr[i].addr.s6_addr32[3] = 0;
 600
 601                 if (addr[i].preferred < UINT32_MAX - now)
 602                         addr[i].preferred += now;
 603
 604                 if (addr[i].valid < UINT32_MAX - now)
 605                         addr[i].valid += now;
 606         }
 607
 608         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 609         border->assigned = 1 << (64 - minprefix);
 610
 611         bool change = len != (int)iface->ia_addr_len;
 612         for (int i = 0; !change && i < len; ++i)
 613                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 614                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 615                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 616                                 (addr[i].valid > (uint32_t)now + 7200) !=
 617                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 618                         change = true;
 619
 620         if (change) {
 621                 struct dhcpv6_assignment *c;
 622                 list_for_each_entry(c, &iface->ia_assignments, head)
 623                         if (c != border)
 624                                 apply_lease(iface, c, false);
 625         }
 626
 627         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 628         iface->ia_addr_len = len;
 629
 630         if (change) { // Addresses / prefixes have changed
 631                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 632                 struct dhcpv6_assignment *c, *d;
 633                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 634                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 635                                 continue;
 636
 637                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 638                                 list_move(&c->head, &reassign);
 639                         else if (c != border)
 640                                 apply_lease(iface, c, true);
 641
 642                         if (c->accept_reconf && c->reconf_cnt == 0) {
 643                                 c->reconf_cnt = 1;
 644                                 c->reconf_sent = now;
 645                                 send_reconf(iface, c);
 646
 647                                 // Leave all other assignments of that client alone
 648                                 struct dhcpv6_assignment *a;
 649                                 list_for_each_entry(a, &iface->ia_assignments, head)
 650                                         if (a != c && a->clid_len == c->clid_len &&
 651                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 652                                                 c->reconf_cnt = INT_MAX;
 653                         }
 654                 }
 655
 656                 while (!list_empty(&reassign)) {
 657                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 658                         list_del(&c->head);
 659                         if (!assign_pd(iface, c)) {
 660                                 c->assigned = 0;
 661                                 list_add(&c->head, &iface->ia_assignments);
 662                         }
 663                 }
 664
 665                 dhcpv6_write_statefile();
 666         }
 667 }
 668
 669
 670 static void reconf_timer(struct uloop_timeout *event)
 671 {
 672         time_t now = odhcpd_time();
 673         struct interface *iface;
 674         list_for_each_entry(iface, &interfaces, head) {
 675                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 676                         continue;
 677
 678                 struct dhcpv6_assignment *a, *n;
 679                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 680                         if (a->valid_until < now) {
 681                                 if ((a->length < 128 && a->clid_len > 0) ||
 682                                                 (a->length == 128 && a->clid_len == 0)) {
 683                                         list_del(&a->head);
 684                                         free_dhcpv6_assignment(a);
 685                                 }
 686                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 687                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 688                                 ++a->reconf_cnt;
 689                                 a->reconf_sent = now;
 690                                 send_reconf(iface, a);
 691                         }
 692                 }
 693         }
 694         uloop_timeout_set(event, 2000);
 695 }
 696
 697
 698 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 699                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 700                 struct interface *iface, bool request)
 701 {
 702         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 703                 return 0;
 704
 705         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 706         size_t datalen = sizeof(out);
 707         time_t now = odhcpd_time();
 708
 709         if (status) {
 710                 struct __attribute__((packed)) {
 711                         uint16_t type;
 712                         uint16_t len;
 713                         uint16_t value;
 714                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 715                                 htons(status)};
 716
 717                 memcpy(buf + datalen, &stat, sizeof(stat));
 718                 datalen += sizeof(stat);
 719         } else {
 720                 if (a) {
 721                         uint32_t pref = 3600;
 722                         uint32_t valid = 3600;
 723
 724                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 725                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 726
 727                         for (size_t i = 0; i < addrlen; ++i) {
 728                                 bool match = true;
 729                                 if (addrs[i].has_class) {
 730                                         match = false;
 731                                         if (a->classes_cnt) {
 732                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 733                                                         if (a->classes[j] == addrs[i].class)
 734                                                                 match = true;
 735                                         } else if (a->all_class) {
 736                                                 match = true;
 737                                         }
 738                                 }
 739
 740                                 if (!match)
 741                                         continue;
 742
 743                                 uint32_t prefix_pref = addrs[i].preferred - now;
 744                                 uint32_t prefix_valid = addrs[i].valid - now;
 745
 746                                 if (addrs[i].prefix > 96 ||
 747                                                 addrs[i].preferred <= (uint32_t)now)
 748                                         continue;
 749
 750                                 if (prefix_pref > 86400)
 751                                         prefix_pref = 86400;
 752
 753                                 if (prefix_valid > 86400)
 754                                         prefix_valid = 86400;
 755
 756 #ifdef DHCPV6_OPT_PREFIX_CLASS
 757                                 struct {
 758                                         uint16_t code;
 759                                         uint16_t length;
 760                                         uint16_t class;
 761                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 762                                         htons(2), htons(iface->ia_addr[i].class)};
 763 #endif
 764
 765                                 if (a->length < 128) {
 766                                         struct dhcpv6_ia_prefix p = {
 767                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 768                                                 .len = htons(sizeof(p) - 4),
 769                                                 .preferred = htonl(prefix_pref),
 770                                                 .valid = htonl(prefix_valid),
 771                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 772                                                 .addr = addrs[i].addr
 773                                         };
 774                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 775
 776                                         size_t entrlen = sizeof(p) - 4;
 777
 778 #ifdef DHCPV6_OPT_PREFIX_CLASS
 779                                         if (iface->ia_addr[i].has_class) {
 780                                                 entrlen += sizeof(pclass);
 781                                                 p.len = htons(entrlen);
 782                                         }
 783 #endif
 784
 785                                         if (datalen + entrlen + 4 > buflen ||
 786                                                         (a->assigned == 0 && a->managed_size == 0))
 787                                                 continue;
 788
 789                                         memcpy(buf + datalen, &p, sizeof(p));
 790 #ifdef DHCPV6_OPT_PREFIX_CLASS
 791                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 792 #endif
 793                                         datalen += entrlen + 4;
 794                                 } else {
 795                                         struct dhcpv6_ia_addr n = {
 796                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 797                                                 .len = htons(sizeof(n) - 4),
 798                                                 .addr = addrs[i].addr,
 799                                                 .preferred = htonl(prefix_pref),
 800                                                 .valid = htonl(prefix_valid)
 801                                         };
 802                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 803                                         size_t entrlen = sizeof(n) - 4;
 804
 805 #ifdef DHCPV6_OPT_PREFIX_CLASS
 806                                         if (iface->ia_addr[i].has_class) {
 807                                                 entrlen += sizeof(pclass);
 808                                                 n.len = htons(entrlen);
 809                                         }
 810 #endif
 811
 812                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 813                                                 continue;
 814
 815                                         memcpy(buf + datalen, &n, sizeof(n));
 816 #ifdef DHCPV6_OPT_PREFIX_CLASS
 817                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 818 #endif
 819                                         datalen += entrlen + 4;
 820                                 }
 821
 822                                 // Calculate T1 / T2 based on non-deprecated addresses
 823                                 if (prefix_pref > 0) {
 824                                         if (prefix_pref < pref)
 825                                                 pref = prefix_pref;
 826
 827                                         if (prefix_valid < valid)
 828                                                 valid = prefix_valid;
 829                                 }
 830                         }
 831
 832                         a->valid_until = valid + now;
 833                         out.t1 = htonl(pref * 5 / 10);
 834                         out.t2 = htonl(pref * 8 / 10);
 835
 836                         if (!out.t1)
 837                                 out.t1 = htonl(1);
 838
 839                         if (!out.t2)
 840                                 out.t2 = htonl(1);
 841                 }
 842
 843                 if (!request) {
 844                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 845                         uint16_t otype, olen;
 846                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 847                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 848                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 849                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 850                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 851                                         continue;
 852
 853                                 bool found = false;
 854                                 if (a) {
 855                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 856                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 857
 858                                         for (size_t i = 0; i < addrlen; ++i) {
 859                                                 if (addrs[i].prefix > 96 ||
 860                                                                 addrs[i].preferred <= (uint32_t)now)
 861                                                         continue;
 862
 863                                                 struct in6_addr addr = addrs[i].addr;
 864                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 865                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 866
 867                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 868                                                                         p->prefix == a->length)
 869                                                                 found = true;
 870                                                 } else {
 871                                                         addr.s6_addr32[3] = htonl(a->assigned);
 872
 873                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 874                                                                 found = true;
 875                                                 }
 876                                         }
 877                                 }
 878
 879                                 if (!found) {
 880                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 881                                                 struct dhcpv6_ia_prefix inv = {
 882                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 883                                                         .len = htons(sizeof(inv) - 4),
 884                                                         .preferred = 0,
 885                                                         .valid = 0,
 886                                                         .prefix = p->prefix,
 887                                                         .addr = p->addr
 888                                                 };
 889
 890                                                 if (datalen + sizeof(inv) > buflen)
 891                                                         continue;
 892
 893                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 894                                                 datalen += sizeof(inv);
 895                                         } else {
 896                                                 struct dhcpv6_ia_addr inv = {
 897                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 898                                                         .len = htons(sizeof(inv) - 4),
 899                                                         .addr = n->addr,
 900                                                         .preferred = 0,
 901                                                         .valid = 0
 902                                                 };
 903
 904                                                 if (datalen + sizeof(inv) > buflen)
 905                                                         continue;
 906
 907                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 908                                                 datalen += sizeof(inv);
 909                                         }
 910                                 }
 911                         }
 912                 }
 913         }
 914
 915         out.len = htons(datalen - 4);
 916         memcpy(buf, &out, sizeof(out));
 917         return datalen;
 918 }
 919
 920
 921 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 922                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 923 {
 924         time_t now = odhcpd_time();
 925         size_t response_len = 0;
 926         const struct dhcpv6_client_header *hdr = data;
 927         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 928         uint16_t otype, olen;
 929
 930         // Find and parse client-id and hostname
 931         bool accept_reconf = false;
 932         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 933         char hostname[256];
 934         size_t hostname_len = 0;
 935         bool class_oro = false;
 936         bool notonlink = false;
 937
 938         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 939                 if (otype == DHCPV6_OPT_CLIENTID) {
 940                         clid_data = odata;
 941                         clid_len = olen;
 942
 943                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 944                                 memcpy(mac, &odata[8], sizeof(mac));
 945                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 946                                 memcpy(mac, &odata[4], sizeof(mac));
 947                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 948                         uint8_t fqdn_buf[256];
 949                         memcpy(fqdn_buf, odata, olen);
 950                         fqdn_buf[olen++] = 0;
 951
 952                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 953                                 hostname_len = strcspn(hostname, ".");
 954                 } else if (otype == DHCPV6_OPT_ORO) {
 955 #ifdef DHCPV6_OPT_PREFIX_CLASS
 956                         for (size_t i = 0; i + 1 < olen; i += 2) {
 957                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 958                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 959                                         class_oro = true;
 960                         }
 961 #endif
 962                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 963                         accept_reconf = true;
 964                 }
 965         }
 966
 967         if (!clid_data || !clid_len || clid_len > 130)
 968                 goto out;
 969
 970         update(iface);
 971         bool update_state = false;
 972
 973         struct dhcpv6_assignment *first = NULL;
 974         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 975                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 976                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 977                 bool ia_addr_present = false;
 978                 if (!is_pd && !is_na)
 979                         continue;
 980
 981                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 982                 size_t ia_response_len = 0;
 983                 uint8_t reqlen = (is_pd) ? 62 : 128;
 984                 uint32_t reqhint = 0;
 985
 986                 const uint8_t classes_max = 32;
 987                 uint8_t classes_cnt = 0;
 988                 uint16_t classes[classes_max];
 989
 990                 // Parse request hint for IA-PD
 991                 if (is_pd) {
 992                         uint8_t *sdata;
 993                         uint16_t stype, slen;
 994                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 995                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 996                                         continue;
 997
 998                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 999                                 if (p->prefix) {
1000                                         reqlen = p->prefix;
1001                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1002                                         if (reqlen > 32 && reqlen <= 64)
1003                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1004                                 }
1005
1006 #ifdef DHCPV6_OPT_PREFIX_CLASS
1007                                 uint8_t *xdata;
1008                                 uint16_t xtype, xlen;
1009                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
1010                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
1011                                                 continue;
1012
1013                                         if (classes_cnt >= classes_max)
1014                                                 continue;
1015
1016                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1017                                 }
1018 #endif
1019                         }
1020
1021                         if (reqlen > 64)
1022                                 reqlen = 64;
1023                 } else if (is_na) {
1024                         uint8_t *sdata;
1025                         uint16_t stype, slen;
1026                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1027                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1028                                         continue;
1029
1030                                 ia_addr_present = true;
1031 #ifdef DHCPV6_OPT_PREFIX_CLASS
1032                                 uint8_t *xdata;
1033                                 uint16_t xtype, xlen;
1034                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
1035                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
1036                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
1037                                                 continue;
1038
1039                                         if (classes_cnt >= classes_max)
1040                                                 continue;
1041
1042                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
1043                                 }
1044 #endif
1045                         }
1046                 }
1047
1048                 // Find assignment
1049                 struct dhcpv6_assignment *c, *a = NULL;
1050                 list_for_each_entry(c, &iface->ia_assignments, head) {
1051                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1052                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1053                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1054                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1055                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1056                                 a = c;
1057
1058                                 // Reset state
1059                                 apply_lease(iface, a, false);
1060                                 memcpy(a->clid_data, clid_data, clid_len);
1061                                 a->clid_len = clid_len;
1062                                 a->iaid = ia->iaid;
1063                                 a->peer = *addr;
1064                                 a->reconf_cnt = 0;
1065                                 a->reconf_sent = 0;
1066                                 a->all_class = class_oro;
1067                                 a->classes_cnt = classes_cnt;
1068                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
1069                                 if (a->classes)
1070                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1071                                 break;
1072                         }
1073                 }
1074
1075                 // Generic message handling
1076                 uint16_t status = DHCPV6_STATUS_OK;
1077                 if (a && a->managed_size < 0) {
1078                         return -1;
1079                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1080                         bool assigned = !!a;
1081
1082                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1083                                 a = calloc(1, sizeof(*a) + clid_len);
1084                                 if (a) {
1085                                         a->clid_len = clid_len;
1086                                         a->iaid = ia->iaid;
1087                                         a->length = reqlen;
1088                                         a->peer = *addr;
1089                                         a->assigned = reqhint;
1090                                         a->all_class = class_oro;
1091                                         a->classes_cnt = classes_cnt;
1092                                         if (classes_cnt) {
1093                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
1094                                                 if (a->classes)
1095                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
1096                                         }
1097
1098                                         if (first)
1099                                                 memcpy(a->key, first->key, sizeof(a->key));
1100                                         else
1101                                                 odhcpd_urandom(a->key, sizeof(a->key));
1102                                         memcpy(a->clid_data, clid_data, clid_len);
1103
1104                                         if (is_pd)
1105                                                 while (!(assigned = assign_pd(iface, a)) &&
1106                                                                 !a->managed_size && ++a->length <= 64);
1107                                         else
1108                                                 assigned = assign_na(iface, a);
1109
1110                                         if (a->managed_size && !assigned)
1111                                                 return -1;
1112                                 }
1113                         }
1114
1115                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1116                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1117                         } else if (assigned && !first) { //
1118                                 size_t handshake_len = 4;
1119                                 buf[0] = 0;
1120                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1121                                 buf[2] = 0;
1122                                 buf[3] = 0;
1123
1124                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1125                                         struct dhcpv6_auth_reconfigure auth = {
1126                                                 htons(DHCPV6_OPT_AUTH),
1127                                                 htons(sizeof(auth) - 4),
1128                                                 3, 1, 0,
1129                                                 {htonl(time(NULL)), htonl(++serial)},
1130                                                 1,
1131                                                 {0}
1132                                         };
1133                                         memcpy(auth.key, a->key, sizeof(a->key));
1134                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1135                                         handshake_len += sizeof(auth);
1136                                 }
1137
1138                                 buf += handshake_len;
1139                                 buflen -= handshake_len;
1140                                 response_len += handshake_len;
1141
1142                                 first = a;
1143                         }
1144
1145                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1146
1147                         // Was only a solicitation: mark binding for removal
1148                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1149                                 a->valid_until = 0;
1150                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1151                                 if (hostname_len > 0) {
1152                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1153                                         if (a->hostname) {
1154                                                 memcpy(a->hostname, hostname, hostname_len);
1155                                                 a->hostname[hostname_len] = 0;
1156                                         }
1157                                 }
1158                                 a->accept_reconf = accept_reconf;
1159                                 apply_lease(iface, a, true);
1160                                 update_state = true;
1161                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1162                                 free_dhcpv6_assignment(a);
1163                         }
1164                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1165                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1166                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1167                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1168                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1169                                 status = DHCPV6_STATUS_NOBINDING;
1170                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1171                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1172                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1173                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1174                                 if (a)
1175                                         apply_lease(iface, a, true);
1176                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1177                                 a->valid_until = 0;
1178                                 apply_lease(iface, a, false);
1179                                 update_state = true;
1180                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1181                                 a->clid_len = 0;
1182                                 a->valid_until = now + 3600; // Block address for 1h
1183                                 update_state = true;
1184                         }
1185                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1186                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1187                         notonlink = true;
1188                 }
1189
1190                 buf += ia_response_len;
1191                 buflen -= ia_response_len;
1192                 response_len += ia_response_len;
1193         }
1194
1195         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1196                         response_len + 6 < buflen) {
1197                 buf[0] = 0;
1198                 buf[1] = DHCPV6_OPT_STATUS;
1199                 buf[2] = 0;
1200                 buf[3] = 2;
1201                 buf[4] = 0;
1202                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1203                 response_len += 6;
1204         }
1205
1206         if (update_state)
1207                 dhcpv6_write_statefile();
1208
1209 out:
1210         return response_len;
1211 }