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 reconf_timer(struct uloop_timeout *event);
  38 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  39 static uint32_t serial = 0;
  40 static uint8_t statemd5[16];
  41
  42
  43 int dhcpv6_ia_init(void)
  44 {
  45         uloop_timeout_set(&reconf_event, 2000);
  46         return 0;
  47 }
  48
  49
  50 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  51 {
  52         if (c->managed_sock.fd.registered) {
  53                 ustream_free(&c->managed_sock.stream);
  54                 close(c->managed_sock.fd.fd);
  55         }
  56
  57         if (c->head.next)
  58                 list_del(&c->head);
  59
  60         free(c->managed);
  61         free(c->hostname);
  62         free(c);
  63 }
  64
  65
  66 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  67 {
  68         if (!enable && iface->ia_assignments.next) {
  69                 struct dhcpv6_assignment *c;
  70                 while (!list_empty(&iface->ia_assignments)) {
  71                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  72                         free_dhcpv6_assignment(c);
  73                 }
  74         }
  75
  76         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  77                 if (!iface->ia_assignments.next)
  78                         INIT_LIST_HEAD(&iface->ia_assignments);
  79
  80                 if (list_empty(&iface->ia_assignments)) {
  81                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  82                         if (!border) {
  83                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  84                                 return -1;
  85                         }
  86
  87                         border->length = 64;
  88                         list_add(&border->head, &iface->ia_assignments);
  89                 }
  90
  91                 // Parse static entries
  92                 struct lease *lease;
  93                 list_for_each_entry(lease, &leases, head) {
  94                         // Construct entry
  95                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
  96                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
  97                         if (!a) {
  98                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  99                                         iface->ifname);
 100                                 return -1;
 101                         }
 102
 103                         if (lease->dhcpv4_leasetime > 0)
 104                                 a->leasetime = lease->dhcpv4_leasetime;
 105
 106                         a->clid_len = 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, lease->duid_len);
 116                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 117                         /* Infinite valid */
 118                         a->valid_until = 0;
 119
 120                         // Assign to all interfaces
 121                         struct dhcpv6_assignment *c;
 122                         list_for_each_entry(c, &iface->ia_assignments, head) {
 123                                 if (c->length != 128 || c->assigned > a->assigned) {
 124                                         list_add_tail(&a->head, &c->head);
 125                                         break;
 126                                 } else if (c->assigned == a->assigned) {
 127                                         // Already an assignment with that number
 128                                         break;
 129                                 }
 130                         }
 131
 132                         if (a->head.next) {
 133                                 if (lease->hostname[0]) {
 134                                         free(a->hostname);
 135                                         a->hostname = strdup(lease->hostname);
 136                                 }
 137                         } else {
 138                                 free(a->hostname);
 139                                 free(a);
 140                         }
 141                 }
 142         }
 143         return 0;
 144 }
 145
 146
 147 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 148 {
 149         struct {
 150                 struct dhcpv6_client_header hdr;
 151                 uint16_t srvid_type;
 152                 uint16_t srvid_len;
 153                 uint16_t duid_type;
 154                 uint16_t hardware_type;
 155                 uint8_t mac[6];
 156                 uint16_t msg_type;
 157                 uint16_t msg_len;
 158                 uint8_t msg_id;
 159                 struct dhcpv6_auth_reconfigure auth;
 160                 uint16_t clid_type;
 161                 uint16_t clid_len;
 162                 uint8_t clid_data[128];
 163         } __attribute__((packed)) reconf_msg = {
 164                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 165                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 166                 .srvid_len = htons(10),
 167                 .duid_type = htons(3),
 168                 .hardware_type = htons(1),
 169                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 170                 .msg_len = htons(1),
 171                 .msg_id = DHCPV6_MSG_RENEW,
 172                 .auth = {htons(DHCPV6_OPT_AUTH),
 173                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 174                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 175                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 176                 .clid_len = htons(assign->clid_len),
 177                 .clid_data = {0},
 178         };
 179
 180         odhcpd_get_mac(iface, reconf_msg.mac);
 181         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 182         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 183
 184         md5_ctx_t md5;
 185         uint8_t secretbytes[64];
 186         memset(secretbytes, 0, sizeof(secretbytes));
 187         memcpy(secretbytes, assign->key, sizeof(assign->key));
 188
 189         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 190                 secretbytes[i] ^= 0x36;
 191
 192         md5_begin(&md5);
 193         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 194         md5_hash(iov.iov_base, iov.iov_len, &md5);
 195         md5_end(reconf_msg.auth.key, &md5);
 196
 197         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 198                 secretbytes[i] ^= 0x36;
 199                 secretbytes[i] ^= 0x5c;
 200         }
 201
 202         md5_begin(&md5);
 203         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 204         md5_hash(reconf_msg.auth.key, 16, &md5);
 205         md5_end(reconf_msg.auth.key, &md5);
 206
 207         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 208 }
 209
 210
 211 void dhcpv6_write_statefile(void)
 212 {
 213         md5_ctx_t md5;
 214         md5_begin(&md5);
 215
 216         if (config.dhcp_statefile) {
 217                 time_t now = odhcpd_time(), wall_time = time(NULL);
 218                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 219                 if (fd < 0)
 220                         return;
 221
 222                 lockf(fd, F_LOCK, 0);
 223                 if (ftruncate(fd, 0) < 0) {}
 224
 225                 FILE *fp = fdopen(fd, "w");
 226                 if (!fp) {
 227                         close(fd);
 228                         return;
 229                 }
 230
 231                 struct interface *iface;
 232                 list_for_each_entry(iface, &interfaces, head) {
 233                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 234                                 continue;
 235
 236                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 237                                 struct dhcpv6_assignment *c;
 238                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 239                                         if (c->clid_len == 0 || c->managed_size < 0)
 240                                                 continue;
 241
 242                                         char ipbuf[INET6_ADDRSTRLEN];
 243                                         char leasebuf[512];
 244                                         char duidbuf[264];
 245                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 246
 247                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 248                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
 249                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 250                                                         (c->hostname ? c->hostname : "-"),
 251                                                         (c->valid_until > now ?
 252                                                                 (c->valid_until - now + wall_time) :
 253                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 254                                                         c->assigned, (unsigned)c->length);
 255
 256                                         struct in6_addr addr;
 257                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 258                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 259                                         size_t m = 0;
 260
 261                                         for (size_t i = 0; i < addrlen; ++i)
 262                                                 if (addrs[i].preferred > addrs[m].preferred ||
 263                                                                 (addrs[i].preferred == addrs[m].preferred &&
 264                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 265                                                         m = i;
 266
 267                                         for (size_t i = 0; i < addrlen; ++i) {
 268                                                 if (addrs[i].prefix > 96 || (!INFINITE_VALID(c->valid_until) && c->valid_until <= now) ||
 269                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 270                                                                                 addrs[i].prefix == 64))
 271                                                         continue;
 272
 273                                                 addr = addrs[i].addr;
 274                                                 if (c->length == 128)
 275                                                         addr.s6_addr32[3] = htonl(c->assigned);
 276                                                 else
 277                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 278
 279                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 280
 281                                                 if (c->length == 128 && c->hostname) {
 282                                                         fputs(ipbuf, fp);
 283
 284                                                         char b[256];
 285                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 286                                                                         iface->search, b, sizeof(b)) > 0)
 287                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 288
 289                                                         fprintf(fp, "\t%s\n", c->hostname);
 290                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 291                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 292                                                 }
 293
 294                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 295                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 296                                         }
 297                                         leasebuf[l - 1] = '\n';
 298                                         fwrite(leasebuf, 1, l, fp);
 299                                 }
 300                         }
 301
 302                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 303                                 struct dhcpv4_assignment *c;
 304                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 305                                         char ipbuf[INET6_ADDRSTRLEN];
 306                                         char leasebuf[512];
 307                                         char duidbuf[16];
 308                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 309
 310                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 311                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
 312                                                         iface->ifname, duidbuf,
 313                                                         (c->hostname ? c->hostname : "-"),
 314                                                         (c->valid_until > now ?
 315                                                                 (c->valid_until - now + wall_time) :
 316                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 317                                                         c->addr);
 318
 319                                         struct in_addr addr = {htonl(c->addr)};
 320                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 321
 322                                         if (c->hostname[0]) {
 323                                                 fputs(ipbuf, fp);
 324
 325                                                 char b[256];
 326                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 327                                                                 iface->search, b, sizeof(b)) > 0)
 328                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 329
 330                                                 fprintf(fp, "\t%s\n", c->hostname);
 331                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 332                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 333                                         }
 334
 335                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 336                                         leasebuf[l - 1] = '\n';
 337                                         fwrite(leasebuf, 1, l, fp);
 338                                 }
 339                         }
 340                 }
 341
 342                 fclose(fp);
 343         }
 344
 345         uint8_t newmd5[16];
 346         md5_end(newmd5, &md5);
 347
 348         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 349                 memcpy(statemd5, newmd5, sizeof(statemd5));
 350                 char *argv[2] = {config.dhcp_cb, NULL};
 351                 if (!vfork()) {
 352                         execv(argv[0], argv);
 353                         _exit(128);
 354                 }
 355         }
 356 }
 357
 358
 359 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 360 {
 361         if (a->length > 64 || a->managed_size < 0)
 362                 return;
 363
 364         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 365         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 366
 367         for (size_t i = 0; i < addrlen; ++i) {
 368                 struct in6_addr prefix = addrs[i].addr;
 369                 prefix.s6_addr32[1] |= htonl(a->assigned);
 370                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 371                                 iface, &a->peer.sin6_addr, 1024, add);
 372         }
 373 }
 374
 375
 376 // More data was received from TCP connection
 377 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 378 {
 379         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 380         time_t now = odhcpd_time();
 381         bool first = c->managed_size < 0;
 382
 383         for (;;) {
 384                 int pending;
 385                 char *data = ustream_get_read_buf(s, &pending);
 386                 char *end = memmem(data, pending, "\n\n", 2);
 387
 388                 if (!end)
 389                         break;
 390
 391                 end += 2;
 392                 end[-1] = 0;
 393
 394                 c->managed_size = 0;
 395                 if (c->accept_reconf)
 396                         c->reconf_cnt = 1;
 397
 398                 char *saveptr;
 399                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 400                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 401                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 402
 403                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 404                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 405                                 continue;
 406
 407                         x = strtok_r(NULL, ",", &saveptr2);
 408                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 409                                 continue;
 410
 411                         x = strtok_r(NULL, ",", &saveptr2);
 412                         if (sscanf(x, "%u", &n->preferred) < 1)
 413                                 continue;
 414
 415                         x = strtok_r(NULL, ",", &saveptr2);
 416                         if (sscanf(x, "%u", &n->valid) < 1)
 417                                 continue;
 418
 419                         if (n->preferred > n->valid)
 420                                 continue;
 421
 422                         if (UINT32_MAX - now < n->preferred)
 423                                 n->preferred = UINT32_MAX;
 424                         else
 425                                 n->preferred += now;
 426
 427                         if (UINT32_MAX - now < n->valid)
 428                                 n->valid = UINT32_MAX;
 429                         else
 430                                 n->valid += now;
 431
 432                         n->dprefix = 0;
 433
 434                         ++c->managed_size;
 435                 }
 436
 437                 ustream_consume(s, end - data);
 438         }
 439
 440         if (first && c->managed_size == 0)
 441                 free_dhcpv6_assignment(c);
 442         else if (first)
 443                 c->valid_until = now + 150;
 444 }
 445
 446
 447 // TCP transmission has ended, either because of success or timeout or other error
 448 static void managed_handle_pd_done(struct ustream *s)
 449 {
 450         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 451         c->valid_until = odhcpd_time() + 15;
 452         c->managed_size = 0;
 453         if (c->accept_reconf)
 454                 c->reconf_cnt = 1;
 455 }
 456
 457
 458
 459 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 460 {
 461         struct dhcpv6_assignment *c;
 462
 463         if (iface->dhcpv6_pd_manager[0]) {
 464                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 465                 if (fd >= 0) {
 466                         char iaidbuf[298];
 467                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 468
 469                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 470                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 471                         ustream_fd_init(&assign->managed_sock, fd);
 472                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 473                                         iaidbuf, assign->iaid, assign->length);
 474                         ustream_write_pending(&assign->managed_sock.stream);
 475                         assign->managed_size = -1;
 476                         assign->valid_until = odhcpd_time() + 15;
 477                         list_add(&assign->head, &iface->ia_assignments);
 478
 479                         // Wait initial period of up to 250ms for immediate assignment
 480                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 481                         poll(&pfd, 1, 250);
 482                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 483
 484                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 485                                 return true;
 486                 }
 487
 488                 return false;
 489         } else if (iface->ia_addr_len < 1) {
 490                 return false;
 491         }
 492
 493         // Try honoring the hint first
 494         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 495         if (assign->assigned) {
 496                 list_for_each_entry(c, &iface->ia_assignments, head) {
 497                         if (c->length == 128 || c->length == 0)
 498                                 continue;
 499
 500                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 501                                 list_add_tail(&assign->head, &c->head);
 502                                 apply_lease(iface, assign, true);
 503                                 return true;
 504                         }
 505
 506                         if (c->assigned != 0)
 507                                 current = (c->assigned + (1 << (64 - c->length)));
 508                 }
 509         }
 510
 511         // Fallback to a variable assignment
 512         current = 1;
 513         list_for_each_entry(c, &iface->ia_assignments, head) {
 514                 if (c->length == 128 || c->length == 0)
 515                         continue;
 516
 517                 current = (current + asize) & (~asize);
 518                 if (current + asize < c->assigned) {
 519                         assign->assigned = current;
 520                         list_add_tail(&assign->head, &c->head);
 521                         apply_lease(iface, assign, true);
 522                         return true;
 523                 }
 524
 525                 if (c->assigned != 0)
 526                         current = (c->assigned + (1 << (64 - c->length)));
 527         }
 528
 529         return false;
 530 }
 531
 532
 533 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 534 {
 535         // Seed RNG with checksum of DUID
 536         uint32_t seed = 0;
 537         for (size_t i = 0; i < assign->clid_len; ++i)
 538                 seed += assign->clid_data[i];
 539         srand(seed);
 540
 541         // Try to assign up to 100x
 542         for (size_t i = 0; i < 100; ++i) {
 543                 uint32_t try;
 544                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 545
 546                 struct dhcpv6_assignment *c;
 547                 list_for_each_entry(c, &iface->ia_assignments, head) {
 548                         if (c->length == 0)
 549                                 continue;
 550
 551                         if (c->assigned > try || c->length != 128) {
 552                                 assign->assigned = try;
 553                                 list_add_tail(&assign->head, &c->head);
 554                                 return true;
 555                         } else if (c->assigned == try) {
 556                                 break;
 557                         }
 558                 }
 559         }
 560
 561         return false;
 562 }
 563
 564 void dhcpv6_ia_preupdate(struct interface *iface)
 565 {
 566         if (iface->dhcpv6 != RELAYD_SERVER)
 567                 return;
 568
 569         struct dhcpv6_assignment *c, *border = list_last_entry(
 570                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 571         list_for_each_entry(c, &iface->ia_assignments, head)
 572                 if (c != border && !iface->managed)
 573                         apply_lease(iface, c, false);
 574 }
 575
 576 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 577 {
 578         if (iface->dhcpv6 != RELAYD_SERVER)
 579                 return;
 580
 581         int minprefix = -1;
 582         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 583                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 584                                 iface->ia_addr[i].prefix < 64 &&
 585                                 iface->ia_addr[i].prefix > minprefix)
 586                         minprefix = iface->ia_addr[i].prefix;
 587         }
 588
 589         struct dhcpv6_assignment *border = list_last_entry(
 590                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 591         if (minprefix > 32 && minprefix <= 64)
 592                 border->assigned = 1U << (64 - minprefix);
 593         else
 594                 border->assigned = 0;
 595
 596         struct list_head reassign = LIST_HEAD_INIT(reassign);
 597         struct dhcpv6_assignment *c, *d;
 598         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 599                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
 600                                 c->managed_size)
 601                         continue;
 602
 603                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 604                         list_move(&c->head, &reassign);
 605                 else if (c != border)
 606                         apply_lease(iface, c, true);
 607
 608                 if (c->accept_reconf && c->reconf_cnt == 0) {
 609                         c->reconf_cnt = 1;
 610                         c->reconf_sent = now;
 611                         send_reconf(iface, c);
 612
 613                         // Leave all other assignments of that client alone
 614                         struct dhcpv6_assignment *a;
 615                         list_for_each_entry(a, &iface->ia_assignments, head)
 616                                 if (a != c && a->clid_len == c->clid_len &&
 617                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 618                                         c->reconf_cnt = INT_MAX;
 619                 }
 620         }
 621
 622         while (!list_empty(&reassign)) {
 623                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 624                 list_del(&c->head);
 625                 if (!assign_pd(iface, c)) {
 626                         c->assigned = 0;
 627                         list_add(&c->head, &iface->ia_assignments);
 628                 }
 629         }
 630
 631         dhcpv6_write_statefile();
 632 }
 633
 634
 635 static void reconf_timer(struct uloop_timeout *event)
 636 {
 637         time_t now = odhcpd_time();
 638         struct interface *iface;
 639         list_for_each_entry(iface, &interfaces, head) {
 640                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 641                         continue;
 642
 643                 struct dhcpv6_assignment *a, *n;
 644                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 645                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
 646                                 if ((a->length < 128 && a->clid_len > 0) ||
 647                                                 (a->length == 128 && a->clid_len == 0)) {
 648                                         list_del(&a->head);
 649                                         free_dhcpv6_assignment(a);
 650                                 }
 651                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 652                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 653                                 ++a->reconf_cnt;
 654                                 a->reconf_sent = now;
 655                                 send_reconf(iface, a);
 656                         }
 657                 }
 658         }
 659         uloop_timeout_set(event, 2000);
 660 }
 661
 662
 663 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 664                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 665                 struct interface *iface, bool request)
 666 {
 667         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 668                 return 0;
 669
 670         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 671         size_t datalen = sizeof(out);
 672         time_t now = odhcpd_time();
 673
 674         if (status) {
 675                 struct __attribute__((packed)) {
 676                         uint16_t type;
 677                         uint16_t len;
 678                         uint16_t value;
 679                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 680                                 htons(status)};
 681
 682                 memcpy(buf + datalen, &stat, sizeof(stat));
 683                 datalen += sizeof(stat);
 684         } else {
 685                 if (a) {
 686                         uint32_t leasetime;
 687                         if (a->leasetime > 0) {
 688                                 leasetime = a->leasetime;
 689                         } else {
 690                                 leasetime = iface->dhcpv4_leasetime;
 691                         }
 692                         if (leasetime == 0)
 693                                 leasetime = 3600;
 694                         else if (leasetime < 60)
 695                                 leasetime = 60;
 696
 697                         uint32_t pref = leasetime;
 698                         uint32_t valid = leasetime;
 699
 700                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 701                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 702                         size_t m = 0;
 703
 704                         for (size_t i = 0; i < addrlen; ++i)
 705                                 if (addrs[i].preferred > addrs[m].preferred ||
 706                                                 (addrs[i].preferred == addrs[m].preferred &&
 707                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 708                                         m = i;
 709
 710                         for (size_t i = 0; i < addrlen; ++i) {
 711                                 uint32_t prefix_pref = addrs[i].preferred;
 712                                 uint32_t prefix_valid = addrs[i].valid;
 713
 714                                 if (addrs[i].prefix > 96 ||
 715                                                 addrs[i].preferred <= (uint32_t)now)
 716                                         continue;
 717
 718                                 if (prefix_pref != UINT32_MAX)
 719                                         prefix_pref -= now;
 720
 721                                 if (prefix_valid != UINT32_MAX)
 722                                         prefix_valid -= now;
 723
 724                                 if (a->length < 128) {
 725                                         struct dhcpv6_ia_prefix p = {
 726                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 727                                                 .len = htons(sizeof(p) - 4),
 728                                                 .preferred = htonl(prefix_pref),
 729                                                 .valid = htonl(prefix_valid),
 730                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 731                                                 .addr = addrs[i].addr
 732                                         };
 733                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 734
 735                                         size_t entrlen = sizeof(p) - 4;
 736
 737                                         if (datalen + entrlen + 4 > buflen ||
 738                                                         (a->assigned == 0 && a->managed_size == 0) ||
 739                                                         (!a->managed_size && a->length <= addrs[i].prefix))
 740                                                 continue;
 741
 742                                         memcpy(buf + datalen, &p, sizeof(p));
 743                                         datalen += entrlen + 4;
 744                                 } else {
 745                                         struct dhcpv6_ia_addr n = {
 746                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 747                                                 .len = htons(sizeof(n) - 4),
 748                                                 .addr = addrs[i].addr,
 749                                                 .preferred = htonl(prefix_pref),
 750                                                 .valid = htonl(prefix_valid)
 751                                         };
 752                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 753                                         size_t entrlen = sizeof(n) - 4;
 754
 755                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 756                                                         addrs[i].prefix <= 64)
 757                                                 continue;
 758
 759                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 760                                                 continue;
 761
 762                                         memcpy(buf + datalen, &n, sizeof(n));
 763                                         datalen += entrlen + 4;
 764                                 }
 765
 766                                 // Calculate T1 / T2 based on non-deprecated addresses
 767                                 if (prefix_pref > 0) {
 768                                         if (prefix_pref < pref)
 769                                                 pref = prefix_pref;
 770
 771                                         if (prefix_valid < valid)
 772                                                 valid = prefix_valid;
 773                                 }
 774                         }
 775
 776                         /* UINT32_MAX is considered as infinite leasetime */
 777                         a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 778                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
 779                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 780
 781                         if (!out.t1)
 782                                 out.t1 = htonl(1);
 783
 784                         if (!out.t2)
 785                                 out.t2 = htonl(1);
 786                 }
 787
 788                 if (!request) {
 789                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 790                         uint16_t otype, olen;
 791                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 792                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 793                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 794                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 795                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 796                                         continue;
 797
 798                                 bool found = false;
 799                                 if (a) {
 800                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 801                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 802
 803                                         for (size_t i = 0; i < addrlen; ++i) {
 804                                                 if (addrs[i].prefix > 96 ||
 805                                                                 addrs[i].preferred <= (uint32_t)now)
 806                                                         continue;
 807
 808                                                 struct in6_addr addr = addrs[i].addr;
 809                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 810                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 811
 812                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 813                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 814                                                                 found = true;
 815                                                 } else {
 816                                                         addr.s6_addr32[3] = htonl(a->assigned);
 817
 818                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 819                                                                 found = true;
 820                                                 }
 821                                         }
 822                                 }
 823
 824                                 if (!found) {
 825                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 826                                                 struct dhcpv6_ia_prefix inv = {
 827                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 828                                                         .len = htons(sizeof(inv) - 4),
 829                                                         .preferred = 0,
 830                                                         .valid = 0,
 831                                                         .prefix = p->prefix,
 832                                                         .addr = p->addr
 833                                                 };
 834
 835                                                 if (datalen + sizeof(inv) > buflen)
 836                                                         continue;
 837
 838                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 839                                                 datalen += sizeof(inv);
 840                                         } else {
 841                                                 struct dhcpv6_ia_addr inv = {
 842                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 843                                                         .len = htons(sizeof(inv) - 4),
 844                                                         .addr = n->addr,
 845                                                         .preferred = 0,
 846                                                         .valid = 0
 847                                                 };
 848
 849                                                 if (datalen + sizeof(inv) > buflen)
 850                                                         continue;
 851
 852                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 853                                                 datalen += sizeof(inv);
 854                                         }
 855                                 }
 856                         }
 857                 }
 858         }
 859
 860         out.len = htons(datalen - 4);
 861         memcpy(buf, &out, sizeof(out));
 862         return datalen;
 863 }
 864
 865
 866 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 867                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 868 {
 869         const char *type = "UNKNOWN";
 870         const char *status = "UNKNOWN";
 871
 872         if (msgtype == DHCPV6_MSG_RENEW)
 873                 return;
 874
 875         switch (msgtype) {
 876         case DHCPV6_MSG_SOLICIT:
 877                 type = "SOLICIT";
 878                 break;
 879         case DHCPV6_MSG_REQUEST:
 880                 type = "REQUEST";
 881                 break;
 882         case DHCPV6_MSG_CONFIRM:
 883                 type = "CONFIRM";
 884                 break;
 885         case DHCPV6_MSG_RENEW:
 886                 type = "RENEW";
 887                 break;
 888         case DHCPV6_MSG_REBIND:
 889                 type = "REBIND";
 890                 break;
 891         case DHCPV6_MSG_RELEASE:
 892                 type = "RELEASE";
 893                 break;
 894         case DHCPV6_MSG_DECLINE:
 895                 type = "DECLINE";
 896                 break;
 897         }
 898
 899         switch (code) {
 900         case DHCPV6_STATUS_OK:
 901                 status = "ok";
 902                 break;
 903         case DHCPV6_STATUS_NOADDRSAVAIL:
 904                 status = "no addresses available";
 905                 break;
 906         case DHCPV6_STATUS_NOBINDING:
 907                 status = "no binding";
 908                 break;
 909         case DHCPV6_STATUS_NOTONLINK:
 910                 status = "not on-link";
 911                 break;
 912         case DHCPV6_STATUS_NOPREFIXAVAIL:
 913                 status = "no prefix available";
 914                 break;
 915         }
 916
 917         char leasebuf[256] = "";
 918
 919         if (a) {
 920                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 921                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 922                 size_t lbsize = 0;
 923                 char addrbuf[INET6_ADDRSTRLEN];
 924
 925                 for (size_t i = 0; i < addrlen; ++i) {
 926                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 927                                 continue;
 928
 929                         struct in6_addr addr = addrs[i].addr;
 930                         int prefix = a->managed ? addrs[i].prefix : a->length;
 931                         if (prefix == 128)
 932                                 addr.s6_addr32[3] = htonl(a->assigned);
 933                         else
 934                                 addr.s6_addr32[1] |= htonl(a->assigned);
 935
 936                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 937                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 938                 }
 939         }
 940
 941         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 942                         duidbuf, iface->ifname, status, leasebuf);
 943 }
 944
 945
 946
 947 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 948                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 949 {
 950         time_t now = odhcpd_time();
 951         size_t response_len = 0;
 952         const struct dhcpv6_client_header *hdr = data;
 953         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 954         uint16_t otype, olen;
 955
 956         // Find and parse client-id and hostname
 957         bool accept_reconf = false;
 958         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 959         char hostname[256];
 960         size_t hostname_len = 0;
 961         bool notonlink = false;
 962         char duidbuf[261];
 963
 964         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 965                 if (otype == DHCPV6_OPT_CLIENTID) {
 966                         clid_data = odata;
 967                         clid_len = olen;
 968
 969                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 970                                 memcpy(mac, &odata[8], sizeof(mac));
 971                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 972                                 memcpy(mac, &odata[4], sizeof(mac));
 973
 974                         if (olen <= 130)
 975                                 odhcpd_hexlify(duidbuf, odata, olen);
 976                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 977                         uint8_t fqdn_buf[256];
 978                         memcpy(fqdn_buf, odata, olen);
 979                         fqdn_buf[olen++] = 0;
 980
 981                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 982                                 hostname_len = strcspn(hostname, ".");
 983                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 984                         accept_reconf = true;
 985                 }
 986         }
 987
 988         if (!clid_data || !clid_len || clid_len > 130)
 989                 goto out;
 990
 991         struct dhcpv6_assignment *first = NULL;
 992         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 993                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 994                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 995                 bool ia_addr_present = false;
 996                 if (!is_pd && !is_na)
 997                         continue;
 998
 999                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1000                 size_t ia_response_len = 0;
1001                 uint8_t reqlen = (is_pd) ? 62 : 128;
1002                 uint32_t reqhint = 0;
1003
1004                 // Parse request hint for IA-PD
1005                 if (is_pd) {
1006                         uint8_t *sdata;
1007                         uint16_t stype, slen;
1008                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1009                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1010                                         continue;
1011
1012                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1013                                 if (p->prefix) {
1014                                         reqlen = p->prefix;
1015                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1016                                         if (reqlen > 32 && reqlen <= 64)
1017                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1018                                 }
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                         }
1032                 }
1033
1034                 // Find assignment
1035                 struct dhcpv6_assignment *c, *a = NULL;
1036                 list_for_each_entry(c, &iface->ia_assignments, head) {
1037                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1038                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1039                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1040                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1041                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1042                                 a = c;
1043
1044                                 // Reset state
1045                                 apply_lease(iface, a, false);
1046                                 memcpy(a->clid_data, clid_data, clid_len);
1047                                 a->clid_len = clid_len;
1048                                 a->iaid = ia->iaid;
1049                                 a->peer = *addr;
1050                                 a->reconf_cnt = 0;
1051                                 a->reconf_sent = 0;
1052                                 break;
1053                         }
1054                 }
1055
1056                 // Generic message handling
1057                 uint16_t status = DHCPV6_STATUS_OK;
1058                 if (a && a->managed_size < 0) {
1059                         return -1;
1060                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1061                         bool assigned = !!a;
1062
1063                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1064                                 a = calloc(1, sizeof(*a) + clid_len);
1065                                 if (a) {
1066                                         a->clid_len = clid_len;
1067                                         a->iaid = ia->iaid;
1068                                         a->length = reqlen;
1069                                         a->peer = *addr;
1070                                         a->assigned = reqhint;
1071
1072                                         if (first)
1073                                                 memcpy(a->key, first->key, sizeof(a->key));
1074                                         else
1075                                                 odhcpd_urandom(a->key, sizeof(a->key));
1076                                         memcpy(a->clid_data, clid_data, clid_len);
1077
1078                                         if (is_pd)
1079                                                 while (!(assigned = assign_pd(iface, a)) &&
1080                                                                 !a->managed_size && ++a->length <= 64);
1081                                         else
1082                                                 assigned = assign_na(iface, a);
1083
1084                                         if (a->managed_size && !assigned)
1085                                                 return -1;
1086                                 }
1087                         }
1088
1089                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1090                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1091                         } else if (assigned && !first) { //
1092                                 size_t handshake_len = 4;
1093                                 buf[0] = 0;
1094                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1095                                 buf[2] = 0;
1096                                 buf[3] = 0;
1097
1098                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1099                                         struct dhcpv6_auth_reconfigure auth = {
1100                                                 htons(DHCPV6_OPT_AUTH),
1101                                                 htons(sizeof(auth) - 4),
1102                                                 3, 1, 0,
1103                                                 {htonl(time(NULL)), htonl(++serial)},
1104                                                 1,
1105                                                 {0}
1106                                         };
1107                                         memcpy(auth.key, a->key, sizeof(a->key));
1108                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1109                                         handshake_len += sizeof(auth);
1110                                 }
1111
1112                                 buf += handshake_len;
1113                                 buflen -= handshake_len;
1114                                 response_len += handshake_len;
1115
1116                                 first = a;
1117                         }
1118
1119                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1120
1121                         // Was only a solicitation: mark binding for removal
1122                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1123                                 a->valid_until = now;
1124                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1125                                 if (hostname_len > 0) {
1126                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1127                                         if (a->hostname) {
1128                                                 memcpy(a->hostname, hostname, hostname_len);
1129                                                 a->hostname[hostname_len] = 0;
1130                                         }
1131                                 }
1132                                 a->accept_reconf = accept_reconf;
1133                                 apply_lease(iface, a, true);
1134                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1135                                 free_dhcpv6_assignment(a);
1136                         }
1137                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1138                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1139                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1140                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1141                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1142                                 status = DHCPV6_STATUS_NOBINDING;
1143                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1144                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1145                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1146                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1147                                 if (a)
1148                                         apply_lease(iface, a, true);
1149                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1150                                 a->valid_until = now - 1;
1151                                 apply_lease(iface, a, false);
1152                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1153                                 a->clid_len = 0;
1154                                 a->valid_until = now + 3600; // Block address for 1h
1155                         }
1156                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1157                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1158                         status = DHCPV6_STATUS_NOTONLINK;
1159                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1160                         notonlink = true;
1161                 }
1162
1163                 buf += ia_response_len;
1164                 buflen -= ia_response_len;
1165                 response_len += ia_response_len;
1166                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1167         }
1168
1169         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1170                         response_len + 6 < buflen) {
1171                 buf[0] = 0;
1172                 buf[1] = DHCPV6_OPT_STATUS;
1173                 buf[2] = 0;
1174                 buf[3] = 2;
1175                 buf[4] = 0;
1176                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1177                 response_len += 6;
1178         }
1179
1180         dhcpv6_write_statefile();
1181
1182 out:
1183         return response_len;
1184 }