dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include "odhcpd.h"
  17 #include "dhcpv6.h"
  18 #include "dhcpv4.h"
  19 #include "libubox/md5.h"
  20 #include "libubox/usock.h"
  21
  22 #include <time.h>
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <stdio.h>
  26 #include <poll.h>
  27 #include <alloca.h>
  28 #include <resolv.h>
  29 #include <limits.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <stdbool.h>
  34 #include <arpa/inet.h>
  35 #include <sys/timerfd.h>
  36
  37 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
  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 int dhcpv6_ia_init(void)
  44 {
  45         uloop_timeout_set(&reconf_event, 2000);
  46         return 0;
  47 }
  48
  49 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  50 {
  51         if (!enable && iface->ia_assignments.next) {
  52                 struct dhcpv6_assignment *c;
  53                 while (!list_empty(&iface->ia_assignments)) {
  54                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  55                         free_dhcpv6_assignment(c);
  56                 }
  57         }
  58
  59         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  60                 if (!iface->ia_assignments.next)
  61                         INIT_LIST_HEAD(&iface->ia_assignments);
  62
  63                 if (list_empty(&iface->ia_assignments)) {
  64                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  65                         if (!border) {
  66                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  67                                 return -1;
  68                         }
  69
  70                         border->length = 64;
  71                         list_add(&border->head, &iface->ia_assignments);
  72                 }
  73
  74                 // Parse static entries
  75                 struct lease *lease;
  76                 list_for_each_entry(lease, &leases, head) {
  77                         // Construct entry
  78                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
  79                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
  80                         if (!a) {
  81                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  82                                         iface->ifname);
  83                                 return -1;
  84                         }
  85
  86                         if (lease->dhcpv4_leasetime > 0)
  87                                 a->leasetime = lease->dhcpv4_leasetime;
  88
  89                         a->clid_len = duid_len;
  90                         a->length = 128;
  91                         if (lease->hostid) {
  92                                 a->assigned = lease->hostid;
  93                         } else {
  94                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  95                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
  96                         }
  97                         odhcpd_urandom(a->key, sizeof(a->key));
  98                         memcpy(a->clid_data, lease->duid, lease->duid_len);
  99                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 100                         /* Static assignment */
 101                         a->flags |= OAF_STATIC;
 102                         /* Infinite valid */
 103                         a->valid_until = 0;
 104
 105                         // Assign to all interfaces
 106                         struct dhcpv6_assignment *c;
 107                         list_for_each_entry(c, &iface->ia_assignments, head) {
 108                                 if (c->length != 128 || c->assigned > a->assigned) {
 109                                         list_add_tail(&a->head, &c->head);
 110                                         break;
 111                                 } else if (c->assigned == a->assigned) {
 112                                         // Already an assignment with that number
 113                                         break;
 114                                 }
 115                         }
 116
 117                         if (a->head.next) {
 118                                 if (lease->hostname[0]) {
 119                                         free(a->hostname);
 120                                         a->hostname = strdup(lease->hostname);
 121                                 }
 122                         } else {
 123                                 free(a->hostname);
 124                                 free(a);
 125                         }
 126                 }
 127         }
 128         return 0;
 129 }
 130
 131 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
 132 {
 133         if (c->managed_sock.fd.registered) {
 134                 ustream_free(&c->managed_sock.stream);
 135                 close(c->managed_sock.fd.fd);
 136         }
 137
 138         if (c->head.next)
 139                 list_del(&c->head);
 140
 141         free(c->managed);
 142         free(c->hostname);
 143         free(c);
 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 void dhcpv6_write_statefile(void)
 210 {
 211         md5_ctx_t md5;
 212         md5_begin(&md5);
 213
 214         if (config.dhcp_statefile) {
 215                 time_t now = odhcpd_time(), wall_time = time(NULL);
 216                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 217                 if (fd < 0)
 218                         return;
 219
 220                 lockf(fd, F_LOCK, 0);
 221                 if (ftruncate(fd, 0) < 0) {}
 222
 223                 FILE *fp = fdopen(fd, "w");
 224                 if (!fp) {
 225                         close(fd);
 226                         return;
 227                 }
 228
 229                 struct interface *iface;
 230                 list_for_each_entry(iface, &interfaces, head) {
 231                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 232                                 continue;
 233
 234                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 235                                 struct dhcpv6_assignment *c;
 236                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 237                                         if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
 238                                                 continue;
 239
 240                                         char ipbuf[INET6_ADDRSTRLEN];
 241                                         char leasebuf[512];
 242                                         char duidbuf[264];
 243                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 244
 245                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 246                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
 247                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 248                                                         (c->hostname ? c->hostname : "-"),
 249                                                         (c->valid_until > now ?
 250                                                                 (c->valid_until - now + wall_time) :
 251                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 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                                         size_t m = 0;
 258
 259                                         for (size_t i = 0; i < addrlen; ++i)
 260                                                 if (addrs[i].preferred > addrs[m].preferred ||
 261                                                                 (addrs[i].preferred == addrs[m].preferred &&
 262                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 263                                                         m = i;
 264
 265                                         for (size_t i = 0; i < addrlen; ++i) {
 266                                                 if (addrs[i].prefix > 96 || (!INFINITE_VALID(c->valid_until) && c->valid_until <= now) ||
 267                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 268                                                                                 addrs[i].prefix == 64))
 269                                                         continue;
 270
 271                                                 addr = addrs[i].addr;
 272                                                 if (c->length == 128)
 273                                                         addr.s6_addr32[3] = htonl(c->assigned);
 274                                                 else
 275                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 276
 277                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 278
 279                                                 if (c->length == 128 && c->hostname) {
 280                                                         fputs(ipbuf, fp);
 281
 282                                                         char b[256];
 283                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 284                                                                         iface->search, b, sizeof(b)) > 0)
 285                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 286
 287                                                         fprintf(fp, "\t%s\n", c->hostname);
 288                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 289                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 290                                                 }
 291
 292                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 293                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 294                                         }
 295                                         leasebuf[l - 1] = '\n';
 296                                         fwrite(leasebuf, 1, l, fp);
 297                                 }
 298                         }
 299
 300                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 301                                 struct dhcpv4_assignment *c;
 302                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 303                                         if (!(c->flags & OAF_BOUND))
 304                                                 continue;
 305
 306                                         char ipbuf[INET6_ADDRSTRLEN];
 307                                         char leasebuf[512];
 308                                         char duidbuf[16];
 309                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 310
 311                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 312                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
 313                                                         iface->ifname, duidbuf,
 314                                                         (c->hostname ? c->hostname : "-"),
 315                                                         (c->valid_until > now ?
 316                                                                 (c->valid_until - now + wall_time) :
 317                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 318                                                         c->addr);
 319
 320                                         struct in_addr addr = {htonl(c->addr)};
 321                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 322
 323                                         if (c->hostname) {
 324                                                 fputs(ipbuf, fp);
 325
 326                                                 char b[256];
 327                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 328                                                                 iface->search, b, sizeof(b)) > 0)
 329                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 330
 331                                                 fprintf(fp, "\t%s\n", c->hostname);
 332                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 333                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 334                                         }
 335
 336                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 337                                         leasebuf[l - 1] = '\n';
 338                                         fwrite(leasebuf, 1, l, fp);
 339                                 }
 340                         }
 341                 }
 342
 343                 fclose(fp);
 344         }
 345
 346         uint8_t newmd5[16];
 347         md5_end(newmd5, &md5);
 348
 349         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 350                 memcpy(statemd5, newmd5, sizeof(statemd5));
 351                 char *argv[2] = {config.dhcp_cb, NULL};
 352                 if (!vfork()) {
 353                         execv(argv[0], argv);
 354                         _exit(128);
 355                 }
 356         }
 357 }
 358
 359
 360 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 361 {
 362         if (a->length > 64 || a->managed_size < 0)
 363                 return;
 364
 365         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 366         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 367
 368         for (size_t i = 0; i < addrlen; ++i) {
 369                 struct in6_addr prefix = addrs[i].addr;
 370                 prefix.s6_addr32[1] |= htonl(a->assigned);
 371                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 372                                 iface, &a->peer.sin6_addr, 1024, add);
 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 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 458 {
 459         struct dhcpv6_assignment *c;
 460
 461         if (iface->dhcpv6_pd_manager[0]) {
 462                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 463                 if (fd >= 0) {
 464                         char iaidbuf[298];
 465                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 466
 467                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 468                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 469                         ustream_fd_init(&assign->managed_sock, fd);
 470                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 471                                         iaidbuf, assign->iaid, assign->length);
 472                         ustream_write_pending(&assign->managed_sock.stream);
 473                         assign->managed_size = -1;
 474                         assign->valid_until = odhcpd_time() + 15;
 475                         list_add(&assign->head, &iface->ia_assignments);
 476
 477                         // Wait initial period of up to 250ms for immediate assignment
 478                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 479                         poll(&pfd, 1, 250);
 480                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 481
 482                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 483                                 return true;
 484                 }
 485
 486                 return false;
 487         } else if (iface->ia_addr_len < 1) {
 488                 return false;
 489         }
 490
 491         // Try honoring the hint first
 492         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 493         if (assign->assigned) {
 494                 list_for_each_entry(c, &iface->ia_assignments, head) {
 495                         if (c->length == 128 || c->length == 0)
 496                                 continue;
 497
 498                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 499                                 list_add_tail(&assign->head, &c->head);
 500                                 apply_lease(iface, assign, true);
 501                                 return true;
 502                         }
 503
 504                         if (c->assigned != 0)
 505                                 current = (c->assigned + (1 << (64 - c->length)));
 506                 }
 507         }
 508
 509         // Fallback to a variable assignment
 510         current = 1;
 511         list_for_each_entry(c, &iface->ia_assignments, head) {
 512                 if (c->length == 128 || c->length == 0)
 513                         continue;
 514
 515                 current = (current + asize) & (~asize);
 516                 if (current + asize < c->assigned) {
 517                         assign->assigned = current;
 518                         list_add_tail(&assign->head, &c->head);
 519                         apply_lease(iface, assign, true);
 520                         return true;
 521                 }
 522
 523                 if (c->assigned != 0)
 524                         current = (c->assigned + (1 << (64 - c->length)));
 525         }
 526
 527         return false;
 528 }
 529
 530 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 531 {
 532         // Seed RNG with checksum of DUID
 533         uint32_t seed = 0;
 534         for (size_t i = 0; i < assign->clid_len; ++i)
 535                 seed += assign->clid_data[i];
 536         srand(seed);
 537
 538         // Try to assign up to 100x
 539         for (size_t i = 0; i < 100; ++i) {
 540                 uint32_t try;
 541                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 542
 543                 struct dhcpv6_assignment *c;
 544                 list_for_each_entry(c, &iface->ia_assignments, head) {
 545                         if (c->length == 0)
 546                                 continue;
 547
 548                         if (c->assigned > try || c->length != 128) {
 549                                 assign->assigned = try;
 550                                 list_add_tail(&assign->head, &c->head);
 551                                 return true;
 552                         } else if (c->assigned == try) {
 553                                 break;
 554                         }
 555                 }
 556         }
 557
 558         return false;
 559 }
 560
 561 void dhcpv6_ia_preupdate(struct interface *iface)
 562 {
 563         if (iface->dhcpv6 != RELAYD_SERVER)
 564                 return;
 565
 566         struct dhcpv6_assignment *c, *border = list_last_entry(
 567                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 568         list_for_each_entry(c, &iface->ia_assignments, head)
 569                 if (c != border && !iface->managed)
 570                         apply_lease(iface, c, false);
 571 }
 572
 573 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 574 {
 575         if (iface->dhcpv6 != RELAYD_SERVER)
 576                 return;
 577
 578         int minprefix = -1;
 579         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 580                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 581                                 iface->ia_addr[i].prefix < 64 &&
 582                                 iface->ia_addr[i].prefix > minprefix)
 583                         minprefix = iface->ia_addr[i].prefix;
 584         }
 585
 586         struct dhcpv6_assignment *border = list_last_entry(
 587                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 588         if (minprefix > 32 && minprefix <= 64)
 589                 border->assigned = 1U << (64 - minprefix);
 590         else
 591                 border->assigned = 0;
 592
 593         struct list_head reassign = LIST_HEAD_INIT(reassign);
 594         struct dhcpv6_assignment *c, *d;
 595         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 596                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
 597                                 c->managed_size)
 598                         continue;
 599
 600                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 601                         list_move(&c->head, &reassign);
 602                 else if (c != border)
 603                         apply_lease(iface, c, true);
 604
 605                 if (c->accept_reconf && c->reconf_cnt == 0) {
 606                         c->reconf_cnt = 1;
 607                         c->reconf_sent = now;
 608                         send_reconf(iface, c);
 609
 610                         // Leave all other assignments of that client alone
 611                         struct dhcpv6_assignment *a;
 612                         list_for_each_entry(a, &iface->ia_assignments, head)
 613                                 if (a != c && a->clid_len == c->clid_len &&
 614                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 615                                         c->reconf_cnt = INT_MAX;
 616                 }
 617         }
 618
 619         while (!list_empty(&reassign)) {
 620                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 621                 list_del(&c->head);
 622                 if (!assign_pd(iface, c)) {
 623                         c->assigned = 0;
 624                         list_add(&c->head, &iface->ia_assignments);
 625                 }
 626         }
 627
 628         dhcpv6_write_statefile();
 629 }
 630
 631 static void reconf_timer(struct uloop_timeout *event)
 632 {
 633         time_t now = odhcpd_time();
 634         struct interface *iface;
 635         list_for_each_entry(iface, &interfaces, head) {
 636                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 637                         continue;
 638
 639                 struct dhcpv6_assignment *a, *n;
 640                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 641                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
 642                                 if ((a->length < 128 && a->clid_len > 0) ||
 643                                                 (a->length == 128 && a->clid_len == 0)) {
 644                                         list_del(&a->head);
 645                                         free_dhcpv6_assignment(a);
 646                                 }
 647                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 648                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 649                                 ++a->reconf_cnt;
 650                                 a->reconf_sent = now;
 651                                 send_reconf(iface, a);
 652                         }
 653                 }
 654         }
 655         uloop_timeout_set(event, 2000);
 656 }
 657
 658 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 659                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 660                 struct interface *iface, bool request)
 661 {
 662         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 663                 return 0;
 664
 665         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 666         size_t datalen = sizeof(out);
 667         time_t now = odhcpd_time();
 668
 669         if (status) {
 670                 struct __attribute__((packed)) {
 671                         uint16_t type;
 672                         uint16_t len;
 673                         uint16_t value;
 674                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 675                                 htons(status)};
 676
 677                 memcpy(buf + datalen, &stat, sizeof(stat));
 678                 datalen += sizeof(stat);
 679         } else {
 680                 if (a) {
 681                         uint32_t leasetime;
 682                         if (a->leasetime > 0) {
 683                                 leasetime = a->leasetime;
 684                         } else {
 685                                 leasetime = iface->dhcpv4_leasetime;
 686                         }
 687                         if (leasetime == 0)
 688                                 leasetime = 3600;
 689                         else if (leasetime < 60)
 690                                 leasetime = 60;
 691
 692                         uint32_t pref = leasetime;
 693                         uint32_t valid = leasetime;
 694
 695                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 696                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 697                         size_t m = 0;
 698
 699                         for (size_t i = 0; i < addrlen; ++i)
 700                                 if (addrs[i].preferred > addrs[m].preferred ||
 701                                                 (addrs[i].preferred == addrs[m].preferred &&
 702                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 703                                         m = i;
 704
 705                         for (size_t i = 0; i < addrlen; ++i) {
 706                                 uint32_t prefix_pref = addrs[i].preferred;
 707                                 uint32_t prefix_valid = addrs[i].valid;
 708
 709                                 if (addrs[i].prefix > 96 ||
 710                                                 addrs[i].preferred <= (uint32_t)now)
 711                                         continue;
 712
 713                                 if (prefix_pref != UINT32_MAX)
 714                                         prefix_pref -= now;
 715
 716                                 if (prefix_valid != UINT32_MAX)
 717                                         prefix_valid -= now;
 718
 719                                 if (a->length < 128) {
 720                                         struct dhcpv6_ia_prefix p = {
 721                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 722                                                 .len = htons(sizeof(p) - 4),
 723                                                 .preferred = htonl(prefix_pref),
 724                                                 .valid = htonl(prefix_valid),
 725                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 726                                                 .addr = addrs[i].addr
 727                                         };
 728                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 729
 730                                         size_t entrlen = sizeof(p) - 4;
 731
 732                                         if (datalen + entrlen + 4 > buflen ||
 733                                                         (a->assigned == 0 && a->managed_size == 0) ||
 734                                                         (!a->managed_size && a->length <= addrs[i].prefix))
 735                                                 continue;
 736
 737                                         memcpy(buf + datalen, &p, sizeof(p));
 738                                         datalen += entrlen + 4;
 739                                 } else {
 740                                         struct dhcpv6_ia_addr n = {
 741                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 742                                                 .len = htons(sizeof(n) - 4),
 743                                                 .addr = addrs[i].addr,
 744                                                 .preferred = htonl(prefix_pref),
 745                                                 .valid = htonl(prefix_valid)
 746                                         };
 747                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 748                                         size_t entrlen = sizeof(n) - 4;
 749
 750                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 751                                                         addrs[i].prefix <= 64)
 752                                                 continue;
 753
 754                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 755                                                 continue;
 756
 757                                         memcpy(buf + datalen, &n, sizeof(n));
 758                                         datalen += entrlen + 4;
 759                                 }
 760
 761                                 // Calculate T1 / T2 based on non-deprecated addresses
 762                                 if (prefix_pref > 0) {
 763                                         if (prefix_pref < pref)
 764                                                 pref = prefix_pref;
 765
 766                                         if (prefix_valid < valid)
 767                                                 valid = prefix_valid;
 768                                 }
 769                         }
 770
 771                         if (!INFINITE_VALID(a->valid_until))
 772                                 /* UINT32_MAX is considered as infinite leasetime */
 773                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 774
 775                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
 776                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 777
 778                         if (!out.t1)
 779                                 out.t1 = htonl(1);
 780
 781                         if (!out.t2)
 782                                 out.t2 = htonl(1);
 783                 }
 784
 785                 if (!request) {
 786                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 787                         uint16_t otype, olen;
 788                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 789                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 790                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 791                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 792                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 793                                         continue;
 794
 795                                 bool found = false;
 796                                 if (a) {
 797                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 798                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 799
 800                                         for (size_t i = 0; i < addrlen; ++i) {
 801                                                 if (addrs[i].prefix > 96 ||
 802                                                                 addrs[i].preferred <= (uint32_t)now)
 803                                                         continue;
 804
 805                                                 struct in6_addr addr = addrs[i].addr;
 806                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 807                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 808
 809                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 810                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 811                                                                 found = true;
 812                                                 } else {
 813                                                         addr.s6_addr32[3] = htonl(a->assigned);
 814
 815                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 816                                                                 found = true;
 817                                                 }
 818                                         }
 819                                 }
 820
 821                                 if (!found) {
 822                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 823                                                 struct dhcpv6_ia_prefix inv = {
 824                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 825                                                         .len = htons(sizeof(inv) - 4),
 826                                                         .preferred = 0,
 827                                                         .valid = 0,
 828                                                         .prefix = p->prefix,
 829                                                         .addr = p->addr
 830                                                 };
 831
 832                                                 if (datalen + sizeof(inv) > buflen)
 833                                                         continue;
 834
 835                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 836                                                 datalen += sizeof(inv);
 837                                         } else {
 838                                                 struct dhcpv6_ia_addr inv = {
 839                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 840                                                         .len = htons(sizeof(inv) - 4),
 841                                                         .addr = n->addr,
 842                                                         .preferred = 0,
 843                                                         .valid = 0
 844                                                 };
 845
 846                                                 if (datalen + sizeof(inv) > buflen)
 847                                                         continue;
 848
 849                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 850                                                 datalen += sizeof(inv);
 851                                         }
 852                                 }
 853                         }
 854                 }
 855         }
 856
 857         out.len = htons(datalen - 4);
 858         memcpy(buf, &out, sizeof(out));
 859         return datalen;
 860 }
 861
 862 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 863                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 864 {
 865         const char *type = "UNKNOWN";
 866         const char *status = "UNKNOWN";
 867
 868         if (msgtype == DHCPV6_MSG_RENEW)
 869                 return;
 870
 871         switch (msgtype) {
 872         case DHCPV6_MSG_SOLICIT:
 873                 type = "SOLICIT";
 874                 break;
 875         case DHCPV6_MSG_REQUEST:
 876                 type = "REQUEST";
 877                 break;
 878         case DHCPV6_MSG_CONFIRM:
 879                 type = "CONFIRM";
 880                 break;
 881         case DHCPV6_MSG_RENEW:
 882                 type = "RENEW";
 883                 break;
 884         case DHCPV6_MSG_REBIND:
 885                 type = "REBIND";
 886                 break;
 887         case DHCPV6_MSG_RELEASE:
 888                 type = "RELEASE";
 889                 break;
 890         case DHCPV6_MSG_DECLINE:
 891                 type = "DECLINE";
 892                 break;
 893         }
 894
 895         switch (code) {
 896         case DHCPV6_STATUS_OK:
 897                 status = "ok";
 898                 break;
 899         case DHCPV6_STATUS_NOADDRSAVAIL:
 900                 status = "no addresses available";
 901                 break;
 902         case DHCPV6_STATUS_NOBINDING:
 903                 status = "no binding";
 904                 break;
 905         case DHCPV6_STATUS_NOTONLINK:
 906                 status = "not on-link";
 907                 break;
 908         case DHCPV6_STATUS_NOPREFIXAVAIL:
 909                 status = "no prefix available";
 910                 break;
 911         }
 912
 913         char leasebuf[256] = "";
 914
 915         if (a) {
 916                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 917                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 918                 size_t lbsize = 0;
 919                 char addrbuf[INET6_ADDRSTRLEN];
 920
 921                 for (size_t i = 0; i < addrlen; ++i) {
 922                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 923                                 continue;
 924
 925                         struct in6_addr addr = addrs[i].addr;
 926                         int prefix = a->managed ? addrs[i].prefix : a->length;
 927                         if (prefix == 128)
 928                                 addr.s6_addr32[3] = htonl(a->assigned);
 929                         else
 930                                 addr.s6_addr32[1] |= htonl(a->assigned);
 931
 932                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 933                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 934                 }
 935         }
 936
 937         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 938                         duidbuf, iface->ifname, status, leasebuf);
 939 }
 940
 941 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 942                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 943 {
 944         time_t now = odhcpd_time();
 945         size_t response_len = 0;
 946         const struct dhcpv6_client_header *hdr = data;
 947         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 948         uint16_t otype, olen;
 949
 950         // Find and parse client-id and hostname
 951         bool accept_reconf = false;
 952         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 953         char hostname[256];
 954         size_t hostname_len = 0;
 955         bool notonlink = false;
 956         char duidbuf[261];
 957
 958         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 959                 if (otype == DHCPV6_OPT_CLIENTID) {
 960                         clid_data = odata;
 961                         clid_len = olen;
 962
 963                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 964                                 memcpy(mac, &odata[8], sizeof(mac));
 965                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 966                                 memcpy(mac, &odata[4], sizeof(mac));
 967
 968                         if (olen <= 130)
 969                                 odhcpd_hexlify(duidbuf, odata, olen);
 970                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 971                         uint8_t fqdn_buf[256];
 972                         memcpy(fqdn_buf, odata, olen);
 973                         fqdn_buf[olen++] = 0;
 974
 975                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 976                                 hostname_len = strcspn(hostname, ".");
 977                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 978                         accept_reconf = true;
 979                 }
 980         }
 981
 982         if (!clid_data || !clid_len || clid_len > 130)
 983                 goto out;
 984
 985         struct dhcpv6_assignment *first = NULL;
 986         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 987                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 988                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 989                 bool ia_addr_present = false;
 990                 if (!is_pd && !is_na)
 991                         continue;
 992
 993                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 994                 size_t ia_response_len = 0;
 995                 uint8_t reqlen = (is_pd) ? 62 : 128;
 996                 uint32_t reqhint = 0;
 997
 998                 // Parse request hint for IA-PD
 999                 if (is_pd) {
1000                         uint8_t *sdata;
1001                         uint16_t stype, slen;
1002                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1003                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1004                                         continue;
1005
1006                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1007                                 if (p->prefix) {
1008                                         reqlen = p->prefix;
1009                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1010                                         if (reqlen > 32 && reqlen <= 64)
1011                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1012                                 }
1013                         }
1014
1015                         if (reqlen > 64)
1016                                 reqlen = 64;
1017                 } else if (is_na) {
1018                         uint8_t *sdata;
1019                         uint16_t stype, slen;
1020                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1021                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1022                                         continue;
1023
1024                                 ia_addr_present = true;
1025                         }
1026                 }
1027
1028                 // Find assignment
1029                 struct dhcpv6_assignment *c, *a = NULL;
1030                 list_for_each_entry(c, &iface->ia_assignments, head) {
1031                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1032                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1033                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1034                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1035                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1036                                 a = c;
1037
1038                                 // Reset state
1039                                 apply_lease(iface, a, false);
1040                                 memcpy(a->clid_data, clid_data, clid_len);
1041                                 a->clid_len = clid_len;
1042                                 a->iaid = ia->iaid;
1043                                 a->peer = *addr;
1044                                 a->reconf_cnt = 0;
1045                                 a->reconf_sent = 0;
1046                                 break;
1047                         }
1048                 }
1049
1050                 // Generic message handling
1051                 uint16_t status = DHCPV6_STATUS_OK;
1052                 if (a && a->managed_size < 0) {
1053                         return -1;
1054                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1055                         bool assigned = !!a;
1056
1057                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1058                                 a = calloc(1, sizeof(*a) + clid_len);
1059                                 if (a) {
1060                                         a->clid_len = clid_len;
1061                                         a->iaid = ia->iaid;
1062                                         a->length = reqlen;
1063                                         a->peer = *addr;
1064                                         a->assigned = reqhint;
1065                                         // Set valid time to current time indicating
1066                                         // assignment is not having infinite lifetime
1067                                         a->valid_until = now;
1068
1069                                         if (first)
1070                                                 memcpy(a->key, first->key, sizeof(a->key));
1071                                         else
1072                                                 odhcpd_urandom(a->key, sizeof(a->key));
1073                                         memcpy(a->clid_data, clid_data, clid_len);
1074
1075                                         if (is_pd)
1076                                                 while (!(assigned = assign_pd(iface, a)) &&
1077                                                                 !a->managed_size && ++a->length <= 64);
1078                                         else
1079                                                 assigned = assign_na(iface, a);
1080
1081                                         if (a->managed_size && !assigned)
1082                                                 return -1;
1083                                 }
1084                         }
1085
1086                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1087                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1088                         } else if (assigned && !first) { //
1089                                 size_t handshake_len = 4;
1090                                 buf[0] = 0;
1091                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1092                                 buf[2] = 0;
1093                                 buf[3] = 0;
1094
1095                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1096                                         struct dhcpv6_auth_reconfigure auth = {
1097                                                 htons(DHCPV6_OPT_AUTH),
1098                                                 htons(sizeof(auth) - 4),
1099                                                 3, 1, 0,
1100                                                 {htonl(time(NULL)), htonl(++serial)},
1101                                                 1,
1102                                                 {0}
1103                                         };
1104                                         memcpy(auth.key, a->key, sizeof(a->key));
1105                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1106                                         handshake_len += sizeof(auth);
1107                                 }
1108
1109                                 buf += handshake_len;
1110                                 buflen -= handshake_len;
1111                                 response_len += handshake_len;
1112
1113                                 first = a;
1114                         }
1115
1116                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1117
1118                         // Was only a solicitation: mark binding for removal
1119                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1120                                 a->flags &= ~OAF_BOUND;
1121
1122                                 if (!(a->flags & OAF_STATIC))
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                                 a->flags |= OAF_BOUND;
1134                                 apply_lease(iface, a, true);
1135                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1136                                 free_dhcpv6_assignment(a);
1137                         }
1138                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1139                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1140                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1141                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1142                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1143                                 status = DHCPV6_STATUS_NOBINDING;
1144                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1145                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1146                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1147                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1148                                 if (a) {
1149                                         a->flags |= OAF_BOUND;
1150                                         apply_lease(iface, a, true);
1151                                 }
1152                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1153                                 if (!(a->flags & OAF_STATIC))
1154                                         a->valid_until = now - 1;
1155
1156                                 a->flags &= ~OAF_BOUND;
1157                                 apply_lease(iface, a, false);
1158                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1159                                 a->flags &= ~OAF_BOUND;
1160
1161                                 if (!(a->flags & OAF_STATIC)) {
1162                                         a->clid_len = 0;
1163                                         a->valid_until = now + 3600; // Block address for 1h
1164                                 }
1165                         }
1166                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1167                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1168                         status = DHCPV6_STATUS_NOTONLINK;
1169                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1170                         notonlink = true;
1171                 }
1172
1173                 buf += ia_response_len;
1174                 buflen -= ia_response_len;
1175                 response_len += ia_response_len;
1176                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1177         }
1178
1179         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1180                         response_len + 6 < buflen) {
1181                 buf[0] = 0;
1182                 buf[1] = DHCPV6_OPT_STATUS;
1183                 buf[2] = 0;
1184                 buf[3] = 2;
1185                 buf[4] = 0;
1186                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1187                 response_len += 6;
1188         }
1189
1190         dhcpv6_write_statefile();
1191
1192 out:
1193         return response_len;
1194 }