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                                                 if (c->valid_until <= now)
 262                                                         continue;
 263
 264                                                 addr = addrs[i].addr;
 265                                                 if (c->length == 128)
 266                                                         addr.s6_addr32[3] = htonl(c->assigned);
 267                                                 else
 268                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 269
 270                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 271
 272                                                 if (c->length == 128 && c->hostname) {
 273                                                         fputs(ipbuf, fp);
 274
 275                                                         char b[256];
 276                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 277                                                                         iface->search, b, sizeof(b)) > 0)
 278                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 279
 280                                                         fprintf(fp, "\t%s\n", c->hostname);
 281                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 282                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 283                                                 }
 284
 285                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 286                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 287                                         }
 288                                         leasebuf[l - 1] = '\n';
 289                                         fwrite(leasebuf, 1, l, fp);
 290                                 }
 291                         }
 292
 293                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 294                                 struct dhcpv4_assignment *c;
 295                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 296                                         char ipbuf[INET6_ADDRSTRLEN];
 297                                         char leasebuf[512];
 298                                         char duidbuf[16];
 299                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 300
 301                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 302                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 303                                                         iface->ifname, duidbuf,
 304                                                         (c->hostname ? c->hostname : "-"),
 305                                                         (unsigned)(c->valid_until > now ?
 306                                                                         (c->valid_until - now + wall_time) : 0),
 307                                                         c->addr);
 308
 309                                         struct in_addr addr = {htonl(c->addr)};
 310                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 311
 312                                         if (c->hostname[0]) {
 313                                                 fputs(ipbuf, fp);
 314
 315                                                 char b[256];
 316                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 317                                                                 iface->search, b, sizeof(b)) > 0)
 318                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 319
 320                                                 fprintf(fp, "\t%s\n", c->hostname);
 321                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 322                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 323                                         }
 324
 325                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 326                                         leasebuf[l - 1] = '\n';
 327                                         fwrite(leasebuf, 1, l, fp);
 328                                 }
 329                         }
 330                 }
 331
 332                 fclose(fp);
 333         }
 334
 335         uint8_t newmd5[16];
 336         md5_end(newmd5, &md5);
 337
 338         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 339                 memcpy(statemd5, newmd5, sizeof(statemd5));
 340                 char *argv[2] = {config.dhcp_cb, NULL};
 341                 if (!vfork()) {
 342                         execv(argv[0], argv);
 343                         _exit(128);
 344                 }
 345         }
 346 }
 347
 348
 349 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 350 {
 351         if (a->length > 64 || a->managed_size < 0)
 352                 return;
 353
 354         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 355         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 356
 357         for (size_t i = 0; i < addrlen; ++i) {
 358                 struct in6_addr prefix = addrs[i].addr;
 359                 prefix.s6_addr32[1] |= htonl(a->assigned);
 360                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 361                                 iface, &a->peer.sin6_addr, add);
 362         }
 363 }
 364
 365
 366 // More data was received from TCP connection
 367 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 368 {
 369         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 370         time_t now = odhcpd_time();
 371         bool first = c->managed_size < 0;
 372
 373         for (;;) {
 374                 int pending;
 375                 char *data = ustream_get_read_buf(s, &pending);
 376                 char *end = memmem(data, pending, "\n\n", 2);
 377
 378                 if (!end)
 379                         break;
 380
 381                 end += 2;
 382                 end[-1] = 0;
 383
 384                 c->managed_size = 0;
 385                 if (c->accept_reconf)
 386                         c->reconf_cnt = 1;
 387
 388                 char *saveptr;
 389                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 390                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 391                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 392
 393                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 394                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 395                                 continue;
 396
 397                         x = strtok_r(NULL, ",", &saveptr2);
 398                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 399                                 continue;
 400
 401                         x = strtok_r(NULL, ",", &saveptr2);
 402                         if (sscanf(x, "%u", &n->preferred) < 1)
 403                                 continue;
 404
 405                         x = strtok_r(NULL, ",", &saveptr2);
 406                         if (sscanf(x, "%u", &n->valid) < 1)
 407                                 continue;
 408
 409                         if (n->preferred > n->valid)
 410                                 continue;
 411
 412                         if (UINT32_MAX - now < n->preferred)
 413                                 n->preferred = UINT32_MAX;
 414                         else
 415                                 n->preferred += now;
 416
 417                         if (UINT32_MAX - now < n->valid)
 418                                 n->valid = UINT32_MAX;
 419                         else
 420                                 n->valid += now;
 421
 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         // Seed RNG with checksum of DUID
 526         uint32_t seed = 0;
 527         for (size_t i = 0; i < assign->clid_len; ++i)
 528                 seed += assign->clid_data[i];
 529         srand(seed);
 530
 531         // Try to assign up to 100x
 532         for (size_t i = 0; i < 100; ++i) {
 533                 uint32_t try;
 534                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 535
 536                 struct dhcpv6_assignment *c;
 537                 list_for_each_entry(c, &iface->ia_assignments, head) {
 538                         if (c->length == 0)
 539                                 continue;
 540
 541                         if (c->assigned > try || c->length != 128) {
 542                                 assign->assigned = try;
 543                                 list_add_tail(&assign->head, &c->head);
 544                                 return true;
 545                         } else if (c->assigned == try) {
 546                                 break;
 547                         }
 548                 }
 549         }
 550
 551         return false;
 552 }
 553
 554
 555 static int prefixcmp(const void *va, const void *vb)
 556 {
 557         const struct odhcpd_ipaddr *a = va, *b = vb;
 558         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 559         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 560         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 561 }
 562
 563
 564 static void update(struct interface *iface)
 565 {
 566         struct odhcpd_ipaddr addr[8];
 567         memset(addr, 0, sizeof(addr));
 568         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 569
 570         if (len < 0)
 571                 return;
 572
 573         qsort(addr, len, sizeof(*addr), prefixcmp);
 574
 575         time_t now = odhcpd_time();
 576         int minprefix = -1;
 577
 578         for (int i = 0; i < len; ++i) {
 579                 if (addr[i].preferred > 0 && addr[i].prefix > minprefix)
 580                         minprefix = addr[i].prefix;
 581
 582                 addr[i].addr.s6_addr32[3] = 0;
 583
 584                 if (addr[i].preferred < UINT32_MAX - now)
 585                         addr[i].preferred += now;
 586
 587                 if (addr[i].valid < UINT32_MAX - now)
 588                         addr[i].valid += now;
 589         }
 590
 591         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 592         border->assigned = 1 << (64 - minprefix);
 593
 594         bool change = len != (int)iface->ia_addr_len;
 595         for (int i = 0; !change && i < len; ++i)
 596                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 597                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 598                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 599                                 (addr[i].valid > (uint32_t)now + 7200) !=
 600                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 601                         change = true;
 602
 603         if (change) {
 604                 struct dhcpv6_assignment *c;
 605                 list_for_each_entry(c, &iface->ia_assignments, head)
 606                         if (c != border && !iface->managed)
 607                                 apply_lease(iface, c, false);
 608         }
 609
 610         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 611         iface->ia_addr_len = len;
 612
 613         if (change) { // Addresses / prefixes have changed
 614                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 615                 struct dhcpv6_assignment *c, *d;
 616                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 617                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 618                                 continue;
 619
 620                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 621                                 list_move(&c->head, &reassign);
 622                         else if (c != border)
 623                                 apply_lease(iface, c, true);
 624
 625                         if (c->accept_reconf && c->reconf_cnt == 0) {
 626                                 c->reconf_cnt = 1;
 627                                 c->reconf_sent = now;
 628                                 send_reconf(iface, c);
 629
 630                                 // Leave all other assignments of that client alone
 631                                 struct dhcpv6_assignment *a;
 632                                 list_for_each_entry(a, &iface->ia_assignments, head)
 633                                         if (a != c && a->clid_len == c->clid_len &&
 634                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 635                                                 c->reconf_cnt = INT_MAX;
 636                         }
 637                 }
 638
 639                 while (!list_empty(&reassign)) {
 640                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 641                         list_del(&c->head);
 642                         if (!assign_pd(iface, c)) {
 643                                 c->assigned = 0;
 644                                 list_add(&c->head, &iface->ia_assignments);
 645                         }
 646                 }
 647
 648                 dhcpv6_write_statefile();
 649         }
 650 }
 651
 652
 653 static void reconf_timer(struct uloop_timeout *event)
 654 {
 655         time_t now = odhcpd_time();
 656         struct interface *iface;
 657         list_for_each_entry(iface, &interfaces, head) {
 658                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 659                         continue;
 660
 661                 struct dhcpv6_assignment *a, *n;
 662                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 663                         if (a->valid_until < now) {
 664                                 if ((a->length < 128 && a->clid_len > 0) ||
 665                                                 (a->length == 128 && a->clid_len == 0)) {
 666                                         list_del(&a->head);
 667                                         free_dhcpv6_assignment(a);
 668                                 }
 669                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 670                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 671                                 ++a->reconf_cnt;
 672                                 a->reconf_sent = now;
 673                                 send_reconf(iface, a);
 674                         }
 675                 }
 676         }
 677         uloop_timeout_set(event, 2000);
 678 }
 679
 680
 681 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 682                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 683                 struct interface *iface, bool request)
 684 {
 685         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 686                 return 0;
 687
 688         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 689         size_t datalen = sizeof(out);
 690         time_t now = odhcpd_time();
 691
 692         if (status) {
 693                 struct __attribute__((packed)) {
 694                         uint16_t type;
 695                         uint16_t len;
 696                         uint16_t value;
 697                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 698                                 htons(status)};
 699
 700                 memcpy(buf + datalen, &stat, sizeof(stat));
 701                 datalen += sizeof(stat);
 702         } else {
 703                 if (a) {
 704                         uint32_t leasetime = iface->dhcpv4_leasetime;
 705                         if (leasetime == 0)
 706                                 leasetime = 3600;
 707                         else if (leasetime < 60)
 708                                 leasetime = 60;
 709
 710                         uint32_t pref = leasetime;
 711                         uint32_t valid = leasetime;
 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                         size_t mostpref = 0;
 716
 717                         for (size_t i = 0; i < addrlen; ++i)
 718                                 if (addrs[i].preferred > addrs[mostpref].preferred)
 719                                         mostpref = i;
 720
 721                         for (size_t i = 0; i < addrlen; ++i) {
 722                                 uint32_t prefix_pref = addrs[i].preferred - now;
 723                                 uint32_t prefix_valid = addrs[i].valid - now;
 724
 725                                 if (addrs[i].prefix > 96 ||
 726                                                 addrs[i].preferred <= (uint32_t)now)
 727                                         continue;
 728
 729                                 if (a->length < 128) {
 730                                         struct dhcpv6_ia_prefix p = {
 731                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 732                                                 .len = htons(sizeof(p) - 4),
 733                                                 .preferred = htonl(prefix_pref),
 734                                                 .valid = htonl(prefix_valid),
 735                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 736                                                 .addr = addrs[i].addr
 737                                         };
 738                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 739
 740                                         size_t entrlen = sizeof(p) - 4;
 741
 742                                         if (datalen + entrlen + 4 > buflen ||
 743                                                         (a->assigned == 0 && a->managed_size == 0))
 744                                                 continue;
 745
 746                                         memcpy(buf + datalen, &p, sizeof(p));
 747                                         datalen += entrlen + 4;
 748                                 } else {
 749                                         struct dhcpv6_ia_addr n = {
 750                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 751                                                 .len = htons(sizeof(n) - 4),
 752                                                 .addr = addrs[i].addr,
 753                                                 .preferred = htonl(prefix_pref),
 754                                                 .valid = htonl(prefix_valid)
 755                                         };
 756                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 757                                         size_t entrlen = sizeof(n) - 4;
 758
 759                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != mostpref)
 760                                                 continue;
 761
 762                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 763                                                 continue;
 764
 765                                         memcpy(buf + datalen, &n, sizeof(n));
 766                                         datalen += entrlen + 4;
 767                                 }
 768
 769                                 // Calculate T1 / T2 based on non-deprecated addresses
 770                                 if (prefix_pref > 0) {
 771                                         if (prefix_pref < pref)
 772                                                 pref = prefix_pref;
 773
 774                                         if (prefix_valid < valid)
 775                                                 valid = prefix_valid;
 776                                 }
 777                         }
 778
 779                         a->valid_until = valid + now;
 780                         out.t1 = htonl(pref * 5 / 10);
 781                         out.t2 = htonl(pref * 8 / 10);
 782
 783                         if (!out.t1)
 784                                 out.t1 = htonl(1);
 785
 786                         if (!out.t2)
 787                                 out.t2 = htonl(1);
 788                 }
 789
 790                 if (!request) {
 791                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 792                         uint16_t otype, olen;
 793                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 794                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 795                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 796                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 797                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 798                                         continue;
 799
 800                                 bool found = false;
 801                                 if (a) {
 802                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 803                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 804
 805                                         for (size_t i = 0; i < addrlen; ++i) {
 806                                                 if (addrs[i].prefix > 96 ||
 807                                                                 addrs[i].preferred <= (uint32_t)now)
 808                                                         continue;
 809
 810                                                 struct in6_addr addr = addrs[i].addr;
 811                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 812                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 813
 814                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 815                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 816                                                                 found = true;
 817                                                 } else {
 818                                                         addr.s6_addr32[3] = htonl(a->assigned);
 819
 820                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 821                                                                 found = true;
 822                                                 }
 823                                         }
 824                                 }
 825
 826                                 if (!found) {
 827                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 828                                                 struct dhcpv6_ia_prefix inv = {
 829                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 830                                                         .len = htons(sizeof(inv) - 4),
 831                                                         .preferred = 0,
 832                                                         .valid = 0,
 833                                                         .prefix = p->prefix,
 834                                                         .addr = p->addr
 835                                                 };
 836
 837                                                 if (datalen + sizeof(inv) > buflen)
 838                                                         continue;
 839
 840                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 841                                                 datalen += sizeof(inv);
 842                                         } else {
 843                                                 struct dhcpv6_ia_addr inv = {
 844                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 845                                                         .len = htons(sizeof(inv) - 4),
 846                                                         .addr = n->addr,
 847                                                         .preferred = 0,
 848                                                         .valid = 0
 849                                                 };
 850
 851                                                 if (datalen + sizeof(inv) > buflen)
 852                                                         continue;
 853
 854                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 855                                                 datalen += sizeof(inv);
 856                                         }
 857                                 }
 858                         }
 859                 }
 860         }
 861
 862         out.len = htons(datalen - 4);
 863         memcpy(buf, &out, sizeof(out));
 864         return datalen;
 865 }
 866
 867
 868 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 869                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 870 {
 871         const char *type = "UNKNOWN";
 872         const char *status = "UNKNOWN";
 873
 874         if (msgtype == DHCPV6_MSG_RENEW)
 875                 return;
 876
 877         switch (msgtype) {
 878         case DHCPV6_MSG_SOLICIT:
 879                 type = "SOLICIT";
 880                 break;
 881         case DHCPV6_MSG_REQUEST:
 882                 type = "REQUEST";
 883                 break;
 884         case DHCPV6_MSG_CONFIRM:
 885                 type = "CONFIRM";
 886                 break;
 887         case DHCPV6_MSG_RENEW:
 888                 type = "RENEW";
 889                 break;
 890         case DHCPV6_MSG_REBIND:
 891                 type = "REBIND";
 892                 break;
 893         case DHCPV6_MSG_RELEASE:
 894                 type = "RELEASE";
 895                 break;
 896         case DHCPV6_MSG_DECLINE:
 897                 type = "DECLINE";
 898                 break;
 899         }
 900
 901         switch (code) {
 902         case DHCPV6_STATUS_OK:
 903                 status = "ok";
 904                 break;
 905         case DHCPV6_STATUS_NOADDRSAVAIL:
 906                 status = "no addresses available";
 907                 break;
 908         case DHCPV6_STATUS_NOBINDING:
 909                 status = "no binding";
 910                 break;
 911         case DHCPV6_STATUS_NOTONLINK:
 912                 status = "not on-link";
 913                 break;
 914         case DHCPV6_STATUS_NOPREFIXAVAIL:
 915                 status = "no prefix available";
 916                 break;
 917         }
 918
 919         char leasebuf[256] = "";
 920
 921         if (a) {
 922                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 923                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 924                 size_t lbsize = 0;
 925                 char addrbuf[INET6_ADDRSTRLEN];
 926
 927                 for (size_t i = 0; i < addrlen; ++i) {
 928                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 929                                 continue;
 930
 931                         struct in6_addr addr = addrs[i].addr;
 932                         int prefix = a->managed ? addrs[i].prefix : a->length;
 933                         if (prefix == 128)
 934                                 addr.s6_addr32[3] = htonl(a->assigned);
 935                         else
 936                                 addr.s6_addr32[1] |= htonl(a->assigned);
 937
 938                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 939                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 940                 }
 941         }
 942
 943         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 944                         duidbuf, iface->ifname, status, leasebuf);
 945 }
 946
 947
 948
 949 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 950                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 951 {
 952         time_t now = odhcpd_time();
 953         size_t response_len = 0;
 954         const struct dhcpv6_client_header *hdr = data;
 955         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 956         uint16_t otype, olen;
 957
 958         // Find and parse client-id and hostname
 959         bool accept_reconf = false;
 960         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 961         char hostname[256];
 962         size_t hostname_len = 0;
 963         bool notonlink = false;
 964         char duidbuf[261];
 965
 966         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 967                 if (otype == DHCPV6_OPT_CLIENTID) {
 968                         clid_data = odata;
 969                         clid_len = olen;
 970
 971                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 972                                 memcpy(mac, &odata[8], sizeof(mac));
 973                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 974                                 memcpy(mac, &odata[4], sizeof(mac));
 975
 976                         if (olen <= 130)
 977                                 odhcpd_hexlify(duidbuf, odata, olen);
 978                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 979                         uint8_t fqdn_buf[256];
 980                         memcpy(fqdn_buf, odata, olen);
 981                         fqdn_buf[olen++] = 0;
 982
 983                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 984                                 hostname_len = strcspn(hostname, ".");
 985                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 986                         accept_reconf = true;
 987                 }
 988         }
 989
 990         if (!clid_data || !clid_len || clid_len > 130)
 991                 goto out;
 992
 993         update(iface);
 994
 995         struct dhcpv6_assignment *first = NULL;
 996         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 997                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 998                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 999                 bool ia_addr_present = false;
1000                 if (!is_pd && !is_na)
1001                         continue;
1002
1003                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1004                 size_t ia_response_len = 0;
1005                 uint8_t reqlen = (is_pd) ? 62 : 128;
1006                 uint32_t reqhint = 0;
1007
1008                 // Parse request hint for IA-PD
1009                 if (is_pd) {
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_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1014                                         continue;
1015
1016                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1017                                 if (p->prefix) {
1018                                         reqlen = p->prefix;
1019                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1020                                         if (reqlen > 32 && reqlen <= 64)
1021                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1022                                 }
1023                         }
1024
1025                         if (reqlen > 64)
1026                                 reqlen = 64;
1027                 } else if (is_na) {
1028                         uint8_t *sdata;
1029                         uint16_t stype, slen;
1030                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1031                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1032                                         continue;
1033
1034                                 ia_addr_present = true;
1035                         }
1036                 }
1037
1038                 // Find assignment
1039                 struct dhcpv6_assignment *c, *a = NULL;
1040                 list_for_each_entry(c, &iface->ia_assignments, head) {
1041                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1042                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1043                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1044                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1045                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1046                                 a = c;
1047
1048                                 // Reset state
1049                                 apply_lease(iface, a, false);
1050                                 memcpy(a->clid_data, clid_data, clid_len);
1051                                 a->clid_len = clid_len;
1052                                 a->iaid = ia->iaid;
1053                                 a->peer = *addr;
1054                                 a->reconf_cnt = 0;
1055                                 a->reconf_sent = 0;
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
1076                                         if (first)
1077                                                 memcpy(a->key, first->key, sizeof(a->key));
1078                                         else
1079                                                 odhcpd_urandom(a->key, sizeof(a->key));
1080                                         memcpy(a->clid_data, clid_data, clid_len);
1081
1082                                         if (is_pd)
1083                                                 while (!(assigned = assign_pd(iface, a)) &&
1084                                                                 !a->managed_size && ++a->length <= 64);
1085                                         else
1086                                                 assigned = assign_na(iface, a);
1087
1088                                         if (a->managed_size && !assigned)
1089                                                 return -1;
1090                                 }
1091                         }
1092
1093                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1094                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1095                         } else if (assigned && !first) { //
1096                                 size_t handshake_len = 4;
1097                                 buf[0] = 0;
1098                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1099                                 buf[2] = 0;
1100                                 buf[3] = 0;
1101
1102                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1103                                         struct dhcpv6_auth_reconfigure auth = {
1104                                                 htons(DHCPV6_OPT_AUTH),
1105                                                 htons(sizeof(auth) - 4),
1106                                                 3, 1, 0,
1107                                                 {htonl(time(NULL)), htonl(++serial)},
1108                                                 1,
1109                                                 {0}
1110                                         };
1111                                         memcpy(auth.key, a->key, sizeof(a->key));
1112                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1113                                         handshake_len += sizeof(auth);
1114                                 }
1115
1116                                 buf += handshake_len;
1117                                 buflen -= handshake_len;
1118                                 response_len += handshake_len;
1119
1120                                 first = a;
1121                         }
1122
1123                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1124
1125                         // Was only a solicitation: mark binding for removal
1126                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1127                                 a->valid_until = 0;
1128                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1129                                 if (hostname_len > 0) {
1130                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1131                                         if (a->hostname) {
1132                                                 memcpy(a->hostname, hostname, hostname_len);
1133                                                 a->hostname[hostname_len] = 0;
1134                                         }
1135                                 }
1136                                 a->accept_reconf = accept_reconf;
1137                                 apply_lease(iface, a, true);
1138                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1139                                 free_dhcpv6_assignment(a);
1140                         }
1141                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1142                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1143                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1144                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1145                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1146                                 status = DHCPV6_STATUS_NOBINDING;
1147                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1148                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1149                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1150                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1151                                 if (a)
1152                                         apply_lease(iface, a, true);
1153                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1154                                 a->valid_until = 0;
1155                                 apply_lease(iface, a, false);
1156                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1157                                 a->clid_len = 0;
1158                                 a->valid_until = now + 3600; // Block address for 1h
1159                         }
1160                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1161                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1162                         status = DHCPV6_STATUS_NOTONLINK;
1163                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1164                         notonlink = true;
1165                 }
1166
1167                 buf += ia_response_len;
1168                 buflen -= ia_response_len;
1169                 response_len += ia_response_len;
1170                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1171         }
1172
1173         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1174                         response_len + 6 < buflen) {
1175                 buf[0] = 0;
1176                 buf[1] = DHCPV6_OPT_STATUS;
1177                 buf[2] = 0;
1178                 buf[3] = 2;
1179                 buf[4] = 0;
1180                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1181                 response_len += 6;
1182         }
1183
1184         dhcpv6_write_statefile();
1185
1186 out:
1187         return response_len;
1188 }