src/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
  38 static void reconf_timer(struct uloop_timeout *event);
  39 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  40 static uint32_t serial = 0;
  41 static uint8_t statemd5[16];
  42
  43
  44 int dhcpv6_ia_init(void)
  45 {
  46         uloop_timeout_set(&reconf_event, 2000);
  47         return 0;
  48 }
  49
  50
  51 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  52 {
  53         if (c->managed_sock.fd.registered) {
  54                 ustream_free(&c->managed_sock.stream);
  55                 close(c->managed_sock.fd.fd);
  56         }
  57
  58         if (c->head.next)
  59                 list_del(&c->head);
  60
  61         free(c->managed);
  62         free(c->hostname);
  63         free(c);
  64 }
  65
  66
  67 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  68 {
  69         if (!enable && iface->ia_assignments.next) {
  70                 struct dhcpv6_assignment *c;
  71                 while (!list_empty(&iface->ia_assignments)) {
  72                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  73                         free_dhcpv6_assignment(c);
  74                 }
  75         }
  76
  77         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  78                 if (!iface->ia_assignments.next)
  79                         INIT_LIST_HEAD(&iface->ia_assignments);
  80
  81                 if (list_empty(&iface->ia_assignments)) {
  82                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  83                         if (!border) {
  84                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  85                                 return -1;
  86                         }
  87
  88                         border->length = 64;
  89                         list_add(&border->head, &iface->ia_assignments);
  90                 }
  91
  92                 // Parse static entries
  93                 struct lease *lease;
  94                 list_for_each_entry(lease, &leases, head) {
  95                         // Construct entry
  96                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
  97                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
  98                         if (!a) {
  99                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
 100                                         iface->ifname);
 101                                 return -1;
 102                         }
 103
 104                         if (lease->dhcpv4_leasetime > 0)
 105                                 a->leasetime = lease->dhcpv4_leasetime;
 106
 107                         a->clid_len = duid_len;
 108                         a->length = 128;
 109                         if (lease->hostid) {
 110                                 a->assigned = lease->hostid;
 111                         } else {
 112                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 113                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 114                         }
 115                         odhcpd_urandom(a->key, sizeof(a->key));
 116                         memcpy(a->clid_data, lease->duid, lease->duid_len);
 117                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 118                         /* Static assignment */
 119                         a->flags |= OAF_STATIC;
 120                         /* Infinite valid */
 121                         a->valid_until = 0;
 122
 123                         // Assign to all interfaces
 124                         struct dhcpv6_assignment *c;
 125                         list_for_each_entry(c, &iface->ia_assignments, head) {
 126                                 if (c->length != 128 || c->assigned > a->assigned) {
 127                                         list_add_tail(&a->head, &c->head);
 128                                         break;
 129                                 } else if (c->assigned == a->assigned) {
 130                                         // Already an assignment with that number
 131                                         break;
 132                                 }
 133                         }
 134
 135                         if (a->head.next) {
 136                                 if (lease->hostname[0]) {
 137                                         free(a->hostname);
 138                                         a->hostname = strdup(lease->hostname);
 139                                 }
 140                         } else {
 141                                 free(a->hostname);
 142                                 free(a);
 143                         }
 144                 }
 145         }
 146         return 0;
 147 }
 148
 149
 150 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 151 {
 152         struct {
 153                 struct dhcpv6_client_header hdr;
 154                 uint16_t srvid_type;
 155                 uint16_t srvid_len;
 156                 uint16_t duid_type;
 157                 uint16_t hardware_type;
 158                 uint8_t mac[6];
 159                 uint16_t msg_type;
 160                 uint16_t msg_len;
 161                 uint8_t msg_id;
 162                 struct dhcpv6_auth_reconfigure auth;
 163                 uint16_t clid_type;
 164                 uint16_t clid_len;
 165                 uint8_t clid_data[128];
 166         } __attribute__((packed)) reconf_msg = {
 167                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 168                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 169                 .srvid_len = htons(10),
 170                 .duid_type = htons(3),
 171                 .hardware_type = htons(1),
 172                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 173                 .msg_len = htons(1),
 174                 .msg_id = DHCPV6_MSG_RENEW,
 175                 .auth = {htons(DHCPV6_OPT_AUTH),
 176                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 177                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 178                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 179                 .clid_len = htons(assign->clid_len),
 180                 .clid_data = {0},
 181         };
 182
 183         odhcpd_get_mac(iface, reconf_msg.mac);
 184         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 185         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 186
 187         md5_ctx_t md5;
 188         uint8_t secretbytes[64];
 189         memset(secretbytes, 0, sizeof(secretbytes));
 190         memcpy(secretbytes, assign->key, sizeof(assign->key));
 191
 192         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 193                 secretbytes[i] ^= 0x36;
 194
 195         md5_begin(&md5);
 196         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 197         md5_hash(iov.iov_base, iov.iov_len, &md5);
 198         md5_end(reconf_msg.auth.key, &md5);
 199
 200         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 201                 secretbytes[i] ^= 0x36;
 202                 secretbytes[i] ^= 0x5c;
 203         }
 204
 205         md5_begin(&md5);
 206         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 207         md5_hash(reconf_msg.auth.key, 16, &md5);
 208         md5_end(reconf_msg.auth.key, &md5);
 209
 210         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 211 }
 212
 213
 214 void dhcpv6_write_statefile(void)
 215 {
 216         md5_ctx_t md5;
 217         md5_begin(&md5);
 218
 219         if (config.dhcp_statefile) {
 220                 time_t now = odhcpd_time(), wall_time = time(NULL);
 221                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 222                 if (fd < 0)
 223                         return;
 224
 225                 lockf(fd, F_LOCK, 0);
 226                 if (ftruncate(fd, 0) < 0) {}
 227
 228                 FILE *fp = fdopen(fd, "w");
 229                 if (!fp) {
 230                         close(fd);
 231                         return;
 232                 }
 233
 234                 struct interface *iface;
 235                 list_for_each_entry(iface, &interfaces, head) {
 236                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 237                                 continue;
 238
 239                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 240                                 struct dhcpv6_assignment *c;
 241                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 242                                         if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
 243                                                 continue;
 244
 245                                         char ipbuf[INET6_ADDRSTRLEN];
 246                                         char leasebuf[512];
 247                                         char duidbuf[264];
 248                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 249
 250                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 251                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
 252                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 253                                                         (c->hostname ? c->hostname : "-"),
 254                                                         (c->valid_until > now ?
 255                                                                 (c->valid_until - now + wall_time) :
 256                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 257                                                         c->assigned, (unsigned)c->length);
 258
 259                                         struct in6_addr addr;
 260                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 261                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 262                                         size_t m = 0;
 263
 264                                         for (size_t i = 0; i < addrlen; ++i)
 265                                                 if (addrs[i].preferred > addrs[m].preferred ||
 266                                                                 (addrs[i].preferred == addrs[m].preferred &&
 267                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 268                                                         m = i;
 269
 270                                         for (size_t i = 0; i < addrlen; ++i) {
 271                                                 if (addrs[i].prefix > 96 || (!INFINITE_VALID(c->valid_until) && c->valid_until <= now) ||
 272                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 273                                                                                 addrs[i].prefix == 64))
 274                                                         continue;
 275
 276                                                 addr = addrs[i].addr;
 277                                                 if (c->length == 128)
 278                                                         addr.s6_addr32[3] = htonl(c->assigned);
 279                                                 else
 280                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 281
 282                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 283
 284                                                 if (c->length == 128 && c->hostname) {
 285                                                         fputs(ipbuf, fp);
 286
 287                                                         char b[256];
 288                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 289                                                                         iface->search, b, sizeof(b)) > 0)
 290                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 291
 292                                                         fprintf(fp, "\t%s\n", c->hostname);
 293                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 294                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 295                                                 }
 296
 297                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 298                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 299                                         }
 300                                         leasebuf[l - 1] = '\n';
 301                                         fwrite(leasebuf, 1, l, fp);
 302                                 }
 303                         }
 304
 305                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 306                                 struct dhcpv4_assignment *c;
 307                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 308                                         if (!(c->flags & OAF_BOUND))
 309                                                 continue;
 310
 311                                         char ipbuf[INET6_ADDRSTRLEN];
 312                                         char leasebuf[512];
 313                                         char duidbuf[16];
 314                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 315
 316                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 317                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
 318                                                         iface->ifname, duidbuf,
 319                                                         (c->hostname ? c->hostname : "-"),
 320                                                         (c->valid_until > now ?
 321                                                                 (c->valid_until - now + wall_time) :
 322                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 323                                                         c->addr);
 324
 325                                         struct in_addr addr = {htonl(c->addr)};
 326                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 327
 328                                         if (c->hostname) {
 329                                                 fputs(ipbuf, fp);
 330
 331                                                 char b[256];
 332                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 333                                                                 iface->search, b, sizeof(b)) > 0)
 334                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 335
 336                                                 fprintf(fp, "\t%s\n", c->hostname);
 337                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 338                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 339                                         }
 340
 341                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 342                                         leasebuf[l - 1] = '\n';
 343                                         fwrite(leasebuf, 1, l, fp);
 344                                 }
 345                         }
 346                 }
 347
 348                 fclose(fp);
 349         }
 350
 351         uint8_t newmd5[16];
 352         md5_end(newmd5, &md5);
 353
 354         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 355                 memcpy(statemd5, newmd5, sizeof(statemd5));
 356                 char *argv[2] = {config.dhcp_cb, NULL};
 357                 if (!vfork()) {
 358                         execv(argv[0], argv);
 359                         _exit(128);
 360                 }
 361         }
 362 }
 363
 364
 365 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 366 {
 367         if (a->length > 64 || a->managed_size < 0)
 368                 return;
 369
 370         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 371         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 372
 373         for (size_t i = 0; i < addrlen; ++i) {
 374                 struct in6_addr prefix = addrs[i].addr;
 375                 prefix.s6_addr32[1] |= htonl(a->assigned);
 376                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 377                                 iface, &a->peer.sin6_addr, 1024, add);
 378         }
 379 }
 380
 381
 382 // More data was received from TCP connection
 383 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 384 {
 385         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 386         time_t now = odhcpd_time();
 387         bool first = c->managed_size < 0;
 388
 389         for (;;) {
 390                 int pending;
 391                 char *data = ustream_get_read_buf(s, &pending);
 392                 char *end = memmem(data, pending, "\n\n", 2);
 393
 394                 if (!end)
 395                         break;
 396
 397                 end += 2;
 398                 end[-1] = 0;
 399
 400                 c->managed_size = 0;
 401                 if (c->accept_reconf)
 402                         c->reconf_cnt = 1;
 403
 404                 char *saveptr;
 405                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 406                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 407                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 408
 409                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 410                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 411                                 continue;
 412
 413                         x = strtok_r(NULL, ",", &saveptr2);
 414                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 415                                 continue;
 416
 417                         x = strtok_r(NULL, ",", &saveptr2);
 418                         if (sscanf(x, "%u", &n->preferred) < 1)
 419                                 continue;
 420
 421                         x = strtok_r(NULL, ",", &saveptr2);
 422                         if (sscanf(x, "%u", &n->valid) < 1)
 423                                 continue;
 424
 425                         if (n->preferred > n->valid)
 426                                 continue;
 427
 428                         if (UINT32_MAX - now < n->preferred)
 429                                 n->preferred = UINT32_MAX;
 430                         else
 431                                 n->preferred += now;
 432
 433                         if (UINT32_MAX - now < n->valid)
 434                                 n->valid = UINT32_MAX;
 435                         else
 436                                 n->valid += now;
 437
 438                         n->dprefix = 0;
 439
 440                         ++c->managed_size;
 441                 }
 442
 443                 ustream_consume(s, end - data);
 444         }
 445
 446         if (first && c->managed_size == 0)
 447                 free_dhcpv6_assignment(c);
 448         else if (first)
 449                 c->valid_until = now + 150;
 450 }
 451
 452
 453 // TCP transmission has ended, either because of success or timeout or other error
 454 static void managed_handle_pd_done(struct ustream *s)
 455 {
 456         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 457         c->valid_until = odhcpd_time() + 15;
 458         c->managed_size = 0;
 459         if (c->accept_reconf)
 460                 c->reconf_cnt = 1;
 461 }
 462
 463
 464
 465 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 466 {
 467         struct dhcpv6_assignment *c;
 468
 469         if (iface->dhcpv6_pd_manager[0]) {
 470                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 471                 if (fd >= 0) {
 472                         char iaidbuf[298];
 473                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 474
 475                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 476                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 477                         ustream_fd_init(&assign->managed_sock, fd);
 478                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 479                                         iaidbuf, assign->iaid, assign->length);
 480                         ustream_write_pending(&assign->managed_sock.stream);
 481                         assign->managed_size = -1;
 482                         assign->valid_until = odhcpd_time() + 15;
 483                         list_add(&assign->head, &iface->ia_assignments);
 484
 485                         // Wait initial period of up to 250ms for immediate assignment
 486                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 487                         poll(&pfd, 1, 250);
 488                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 489
 490                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 491                                 return true;
 492                 }
 493
 494                 return false;
 495         } else if (iface->ia_addr_len < 1) {
 496                 return false;
 497         }
 498
 499         // Try honoring the hint first
 500         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 501         if (assign->assigned) {
 502                 list_for_each_entry(c, &iface->ia_assignments, head) {
 503                         if (c->length == 128 || c->length == 0)
 504                                 continue;
 505
 506                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 507                                 list_add_tail(&assign->head, &c->head);
 508                                 apply_lease(iface, assign, true);
 509                                 return true;
 510                         }
 511
 512                         if (c->assigned != 0)
 513                                 current = (c->assigned + (1 << (64 - c->length)));
 514                 }
 515         }
 516
 517         // Fallback to a variable assignment
 518         current = 1;
 519         list_for_each_entry(c, &iface->ia_assignments, head) {
 520                 if (c->length == 128 || c->length == 0)
 521                         continue;
 522
 523                 current = (current + asize) & (~asize);
 524                 if (current + asize < c->assigned) {
 525                         assign->assigned = current;
 526                         list_add_tail(&assign->head, &c->head);
 527                         apply_lease(iface, assign, true);
 528                         return true;
 529                 }
 530
 531                 if (c->assigned != 0)
 532                         current = (c->assigned + (1 << (64 - c->length)));
 533         }
 534
 535         return false;
 536 }
 537
 538
 539 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 540 {
 541         // Seed RNG with checksum of DUID
 542         uint32_t seed = 0;
 543         for (size_t i = 0; i < assign->clid_len; ++i)
 544                 seed += assign->clid_data[i];
 545         srand(seed);
 546
 547         // Try to assign up to 100x
 548         for (size_t i = 0; i < 100; ++i) {
 549                 uint32_t try;
 550                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 551
 552                 struct dhcpv6_assignment *c;
 553                 list_for_each_entry(c, &iface->ia_assignments, head) {
 554                         if (c->length == 0)
 555                                 continue;
 556
 557                         if (c->assigned > try || c->length != 128) {
 558                                 assign->assigned = try;
 559                                 list_add_tail(&assign->head, &c->head);
 560                                 return true;
 561                         } else if (c->assigned == try) {
 562                                 break;
 563                         }
 564                 }
 565         }
 566
 567         return false;
 568 }
 569
 570 void dhcpv6_ia_preupdate(struct interface *iface)
 571 {
 572         if (iface->dhcpv6 != RELAYD_SERVER)
 573                 return;
 574
 575         struct dhcpv6_assignment *c, *border = list_last_entry(
 576                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 577         list_for_each_entry(c, &iface->ia_assignments, head)
 578                 if (c != border && !iface->managed)
 579                         apply_lease(iface, c, false);
 580 }
 581
 582 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 583 {
 584         if (iface->dhcpv6 != RELAYD_SERVER)
 585                 return;
 586
 587         int minprefix = -1;
 588         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 589                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 590                                 iface->ia_addr[i].prefix < 64 &&
 591                                 iface->ia_addr[i].prefix > minprefix)
 592                         minprefix = iface->ia_addr[i].prefix;
 593         }
 594
 595         struct dhcpv6_assignment *border = list_last_entry(
 596                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 597         if (minprefix > 32 && minprefix <= 64)
 598                 border->assigned = 1U << (64 - minprefix);
 599         else
 600                 border->assigned = 0;
 601
 602         struct list_head reassign = LIST_HEAD_INIT(reassign);
 603         struct dhcpv6_assignment *c, *d;
 604         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 605                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
 606                                 c->managed_size)
 607                         continue;
 608
 609                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 610                         list_move(&c->head, &reassign);
 611                 else if (c != border)
 612                         apply_lease(iface, c, true);
 613
 614                 if (c->accept_reconf && c->reconf_cnt == 0) {
 615                         c->reconf_cnt = 1;
 616                         c->reconf_sent = now;
 617                         send_reconf(iface, c);
 618
 619                         // Leave all other assignments of that client alone
 620                         struct dhcpv6_assignment *a;
 621                         list_for_each_entry(a, &iface->ia_assignments, head)
 622                                 if (a != c && a->clid_len == c->clid_len &&
 623                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 624                                         c->reconf_cnt = INT_MAX;
 625                 }
 626         }
 627
 628         while (!list_empty(&reassign)) {
 629                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 630                 list_del(&c->head);
 631                 if (!assign_pd(iface, c)) {
 632                         c->assigned = 0;
 633                         list_add(&c->head, &iface->ia_assignments);
 634                 }
 635         }
 636
 637         dhcpv6_write_statefile();
 638 }
 639
 640
 641 static void reconf_timer(struct uloop_timeout *event)
 642 {
 643         time_t now = odhcpd_time();
 644         struct interface *iface;
 645         list_for_each_entry(iface, &interfaces, head) {
 646                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 647                         continue;
 648
 649                 struct dhcpv6_assignment *a, *n;
 650                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 651                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
 652                                 if ((a->length < 128 && a->clid_len > 0) ||
 653                                                 (a->length == 128 && a->clid_len == 0)) {
 654                                         list_del(&a->head);
 655                                         free_dhcpv6_assignment(a);
 656                                 }
 657                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 658                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 659                                 ++a->reconf_cnt;
 660                                 a->reconf_sent = now;
 661                                 send_reconf(iface, a);
 662                         }
 663                 }
 664         }
 665         uloop_timeout_set(event, 2000);
 666 }
 667
 668
 669 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 670                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 671                 struct interface *iface, bool request)
 672 {
 673         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 674                 return 0;
 675
 676         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 677         size_t datalen = sizeof(out);
 678         time_t now = odhcpd_time();
 679
 680         if (status) {
 681                 struct __attribute__((packed)) {
 682                         uint16_t type;
 683                         uint16_t len;
 684                         uint16_t value;
 685                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 686                                 htons(status)};
 687
 688                 memcpy(buf + datalen, &stat, sizeof(stat));
 689                 datalen += sizeof(stat);
 690         } else {
 691                 if (a) {
 692                         uint32_t leasetime;
 693                         if (a->leasetime > 0) {
 694                                 leasetime = a->leasetime;
 695                         } else {
 696                                 leasetime = iface->dhcpv4_leasetime;
 697                         }
 698                         if (leasetime == 0)
 699                                 leasetime = 3600;
 700                         else if (leasetime < 60)
 701                                 leasetime = 60;
 702
 703                         uint32_t pref = leasetime;
 704                         uint32_t valid = leasetime;
 705
 706                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 707                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 708                         size_t m = 0;
 709
 710                         for (size_t i = 0; i < addrlen; ++i)
 711                                 if (addrs[i].preferred > addrs[m].preferred ||
 712                                                 (addrs[i].preferred == addrs[m].preferred &&
 713                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 714                                         m = i;
 715
 716                         for (size_t i = 0; i < addrlen; ++i) {
 717                                 uint32_t prefix_pref = addrs[i].preferred;
 718                                 uint32_t prefix_valid = addrs[i].valid;
 719
 720                                 if (addrs[i].prefix > 96 ||
 721                                                 addrs[i].preferred <= (uint32_t)now)
 722                                         continue;
 723
 724                                 if (prefix_pref != UINT32_MAX)
 725                                         prefix_pref -= now;
 726
 727                                 if (prefix_valid != UINT32_MAX)
 728                                         prefix_valid -= now;
 729
 730                                 if (a->length < 128) {
 731                                         struct dhcpv6_ia_prefix p = {
 732                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 733                                                 .len = htons(sizeof(p) - 4),
 734                                                 .preferred = htonl(prefix_pref),
 735                                                 .valid = htonl(prefix_valid),
 736                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 737                                                 .addr = addrs[i].addr
 738                                         };
 739                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 740
 741                                         size_t entrlen = sizeof(p) - 4;
 742
 743                                         if (datalen + entrlen + 4 > buflen ||
 744                                                         (a->assigned == 0 && a->managed_size == 0) ||
 745                                                         (!a->managed_size && a->length <= addrs[i].prefix))
 746                                                 continue;
 747
 748                                         memcpy(buf + datalen, &p, sizeof(p));
 749                                         datalen += entrlen + 4;
 750                                 } else {
 751                                         struct dhcpv6_ia_addr n = {
 752                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 753                                                 .len = htons(sizeof(n) - 4),
 754                                                 .addr = addrs[i].addr,
 755                                                 .preferred = htonl(prefix_pref),
 756                                                 .valid = htonl(prefix_valid)
 757                                         };
 758                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 759                                         size_t entrlen = sizeof(n) - 4;
 760
 761                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 762                                                         addrs[i].prefix <= 64)
 763                                                 continue;
 764
 765                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 766                                                 continue;
 767
 768                                         memcpy(buf + datalen, &n, sizeof(n));
 769                                         datalen += entrlen + 4;
 770                                 }
 771
 772                                 // Calculate T1 / T2 based on non-deprecated addresses
 773                                 if (prefix_pref > 0) {
 774                                         if (prefix_pref < pref)
 775                                                 pref = prefix_pref;
 776
 777                                         if (prefix_valid < valid)
 778                                                 valid = prefix_valid;
 779                                 }
 780                         }
 781
 782                         if (!INFINITE_VALID(a->valid_until))
 783                                 /* UINT32_MAX is considered as infinite leasetime */
 784                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 785
 786                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
 787                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 788
 789                         if (!out.t1)
 790                                 out.t1 = htonl(1);
 791
 792                         if (!out.t2)
 793                                 out.t2 = htonl(1);
 794                 }
 795
 796                 if (!request) {
 797                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 798                         uint16_t otype, olen;
 799                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 800                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 801                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 802                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 803                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 804                                         continue;
 805
 806                                 bool found = false;
 807                                 if (a) {
 808                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 809                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 810
 811                                         for (size_t i = 0; i < addrlen; ++i) {
 812                                                 if (addrs[i].prefix > 96 ||
 813                                                                 addrs[i].preferred <= (uint32_t)now)
 814                                                         continue;
 815
 816                                                 struct in6_addr addr = addrs[i].addr;
 817                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 818                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 819
 820                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 821                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 822                                                                 found = true;
 823                                                 } else {
 824                                                         addr.s6_addr32[3] = htonl(a->assigned);
 825
 826                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 827                                                                 found = true;
 828                                                 }
 829                                         }
 830                                 }
 831
 832                                 if (!found) {
 833                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 834                                                 struct dhcpv6_ia_prefix inv = {
 835                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 836                                                         .len = htons(sizeof(inv) - 4),
 837                                                         .preferred = 0,
 838                                                         .valid = 0,
 839                                                         .prefix = p->prefix,
 840                                                         .addr = p->addr
 841                                                 };
 842
 843                                                 if (datalen + sizeof(inv) > buflen)
 844                                                         continue;
 845
 846                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 847                                                 datalen += sizeof(inv);
 848                                         } else {
 849                                                 struct dhcpv6_ia_addr inv = {
 850                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 851                                                         .len = htons(sizeof(inv) - 4),
 852                                                         .addr = n->addr,
 853                                                         .preferred = 0,
 854                                                         .valid = 0
 855                                                 };
 856
 857                                                 if (datalen + sizeof(inv) > buflen)
 858                                                         continue;
 859
 860                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 861                                                 datalen += sizeof(inv);
 862                                         }
 863                                 }
 864                         }
 865                 }
 866         }
 867
 868         out.len = htons(datalen - 4);
 869         memcpy(buf, &out, sizeof(out));
 870         return datalen;
 871 }
 872
 873
 874 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 875                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 876 {
 877         const char *type = "UNKNOWN";
 878         const char *status = "UNKNOWN";
 879
 880         if (msgtype == DHCPV6_MSG_RENEW)
 881                 return;
 882
 883         switch (msgtype) {
 884         case DHCPV6_MSG_SOLICIT:
 885                 type = "SOLICIT";
 886                 break;
 887         case DHCPV6_MSG_REQUEST:
 888                 type = "REQUEST";
 889                 break;
 890         case DHCPV6_MSG_CONFIRM:
 891                 type = "CONFIRM";
 892                 break;
 893         case DHCPV6_MSG_RENEW:
 894                 type = "RENEW";
 895                 break;
 896         case DHCPV6_MSG_REBIND:
 897                 type = "REBIND";
 898                 break;
 899         case DHCPV6_MSG_RELEASE:
 900                 type = "RELEASE";
 901                 break;
 902         case DHCPV6_MSG_DECLINE:
 903                 type = "DECLINE";
 904                 break;
 905         }
 906
 907         switch (code) {
 908         case DHCPV6_STATUS_OK:
 909                 status = "ok";
 910                 break;
 911         case DHCPV6_STATUS_NOADDRSAVAIL:
 912                 status = "no addresses available";
 913                 break;
 914         case DHCPV6_STATUS_NOBINDING:
 915                 status = "no binding";
 916                 break;
 917         case DHCPV6_STATUS_NOTONLINK:
 918                 status = "not on-link";
 919                 break;
 920         case DHCPV6_STATUS_NOPREFIXAVAIL:
 921                 status = "no prefix available";
 922                 break;
 923         }
 924
 925         char leasebuf[256] = "";
 926
 927         if (a) {
 928                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 929                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 930                 size_t lbsize = 0;
 931                 char addrbuf[INET6_ADDRSTRLEN];
 932
 933                 for (size_t i = 0; i < addrlen; ++i) {
 934                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 935                                 continue;
 936
 937                         struct in6_addr addr = addrs[i].addr;
 938                         int prefix = a->managed ? addrs[i].prefix : a->length;
 939                         if (prefix == 128)
 940                                 addr.s6_addr32[3] = htonl(a->assigned);
 941                         else
 942                                 addr.s6_addr32[1] |= htonl(a->assigned);
 943
 944                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 945                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 946                 }
 947         }
 948
 949         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 950                         duidbuf, iface->ifname, status, leasebuf);
 951 }
 952
 953
 954
 955 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 956                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 957 {
 958         time_t now = odhcpd_time();
 959         size_t response_len = 0;
 960         const struct dhcpv6_client_header *hdr = data;
 961         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 962         uint16_t otype, olen;
 963
 964         // Find and parse client-id and hostname
 965         bool accept_reconf = false;
 966         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 967         char hostname[256];
 968         size_t hostname_len = 0;
 969         bool notonlink = false;
 970         char duidbuf[261];
 971
 972         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 973                 if (otype == DHCPV6_OPT_CLIENTID) {
 974                         clid_data = odata;
 975                         clid_len = olen;
 976
 977                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 978                                 memcpy(mac, &odata[8], sizeof(mac));
 979                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 980                                 memcpy(mac, &odata[4], sizeof(mac));
 981
 982                         if (olen <= 130)
 983                                 odhcpd_hexlify(duidbuf, odata, olen);
 984                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 985                         uint8_t fqdn_buf[256];
 986                         memcpy(fqdn_buf, odata, olen);
 987                         fqdn_buf[olen++] = 0;
 988
 989                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 990                                 hostname_len = strcspn(hostname, ".");
 991                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 992                         accept_reconf = true;
 993                 }
 994         }
 995
 996         if (!clid_data || !clid_len || clid_len > 130)
 997                 goto out;
 998
 999         struct dhcpv6_assignment *first = NULL;
1000         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1001                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1002                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1003                 bool ia_addr_present = false;
1004                 if (!is_pd && !is_na)
1005                         continue;
1006
1007                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1008                 size_t ia_response_len = 0;
1009                 uint8_t reqlen = (is_pd) ? 62 : 128;
1010                 uint32_t reqhint = 0;
1011
1012                 // Parse request hint for IA-PD
1013                 if (is_pd) {
1014                         uint8_t *sdata;
1015                         uint16_t stype, slen;
1016                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1017                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1018                                         continue;
1019
1020                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1021                                 if (p->prefix) {
1022                                         reqlen = p->prefix;
1023                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1024                                         if (reqlen > 32 && reqlen <= 64)
1025                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1026                                 }
1027                         }
1028
1029                         if (reqlen > 64)
1030                                 reqlen = 64;
1031                 } else if (is_na) {
1032                         uint8_t *sdata;
1033                         uint16_t stype, slen;
1034                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1035                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1036                                         continue;
1037
1038                                 ia_addr_present = true;
1039                         }
1040                 }
1041
1042                 // Find assignment
1043                 struct dhcpv6_assignment *c, *a = NULL;
1044                 list_for_each_entry(c, &iface->ia_assignments, head) {
1045                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1046                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1047                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1048                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1049                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1050                                 a = c;
1051
1052                                 // Reset state
1053                                 apply_lease(iface, a, false);
1054                                 memcpy(a->clid_data, clid_data, clid_len);
1055                                 a->clid_len = clid_len;
1056                                 a->iaid = ia->iaid;
1057                                 a->peer = *addr;
1058                                 a->reconf_cnt = 0;
1059                                 a->reconf_sent = 0;
1060                                 break;
1061                         }
1062                 }
1063
1064                 // Generic message handling
1065                 uint16_t status = DHCPV6_STATUS_OK;
1066                 if (a && a->managed_size < 0) {
1067                         return -1;
1068                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1069                         bool assigned = !!a;
1070
1071                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1072                                 a = calloc(1, sizeof(*a) + clid_len);
1073                                 if (a) {
1074                                         a->clid_len = clid_len;
1075                                         a->iaid = ia->iaid;
1076                                         a->length = reqlen;
1077                                         a->peer = *addr;
1078                                         a->assigned = reqhint;
1079                                         // Set valid time to current time indicating
1080                                         // assignment is not having infinite lifetime
1081                                         a->valid_until = now;
1082
1083                                         if (first)
1084                                                 memcpy(a->key, first->key, sizeof(a->key));
1085                                         else
1086                                                 odhcpd_urandom(a->key, sizeof(a->key));
1087                                         memcpy(a->clid_data, clid_data, clid_len);
1088
1089                                         if (is_pd)
1090                                                 while (!(assigned = assign_pd(iface, a)) &&
1091                                                                 !a->managed_size && ++a->length <= 64);
1092                                         else
1093                                                 assigned = assign_na(iface, a);
1094
1095                                         if (a->managed_size && !assigned)
1096                                                 return -1;
1097                                 }
1098                         }
1099
1100                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1101                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1102                         } else if (assigned && !first) { //
1103                                 size_t handshake_len = 4;
1104                                 buf[0] = 0;
1105                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1106                                 buf[2] = 0;
1107                                 buf[3] = 0;
1108
1109                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1110                                         struct dhcpv6_auth_reconfigure auth = {
1111                                                 htons(DHCPV6_OPT_AUTH),
1112                                                 htons(sizeof(auth) - 4),
1113                                                 3, 1, 0,
1114                                                 {htonl(time(NULL)), htonl(++serial)},
1115                                                 1,
1116                                                 {0}
1117                                         };
1118                                         memcpy(auth.key, a->key, sizeof(a->key));
1119                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1120                                         handshake_len += sizeof(auth);
1121                                 }
1122
1123                                 buf += handshake_len;
1124                                 buflen -= handshake_len;
1125                                 response_len += handshake_len;
1126
1127                                 first = a;
1128                         }
1129
1130                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1131
1132                         // Was only a solicitation: mark binding for removal
1133                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1134                                 a->flags &= ~OAF_BOUND;
1135
1136                                 if (!(a->flags & OAF_STATIC))
1137                                         a->valid_until = now;
1138                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1139                                 if (hostname_len > 0) {
1140                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1141                                         if (a->hostname) {
1142                                                 memcpy(a->hostname, hostname, hostname_len);
1143                                                 a->hostname[hostname_len] = 0;
1144                                         }
1145                                 }
1146                                 a->accept_reconf = accept_reconf;
1147                                 a->flags |= OAF_BOUND;
1148                                 apply_lease(iface, a, true);
1149                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1150                                 free_dhcpv6_assignment(a);
1151                         }
1152                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1153                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1154                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1155                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1156                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1157                                 status = DHCPV6_STATUS_NOBINDING;
1158                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1159                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1160                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1161                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1162                                 if (a) {
1163                                         a->flags |= OAF_BOUND;
1164                                         apply_lease(iface, a, true);
1165                                 }
1166                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1167                                 if (!(a->flags & OAF_STATIC))
1168                                         a->valid_until = now - 1;
1169
1170                                 a->flags &= ~OAF_BOUND;
1171                                 apply_lease(iface, a, false);
1172                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1173                                 a->flags &= ~OAF_BOUND;
1174
1175                                 if (!(a->flags & OAF_STATIC)) {
1176                                         a->clid_len = 0;
1177                                         a->valid_until = now + 3600; // Block address for 1h
1178                                 }
1179                         }
1180                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1181                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1182                         status = DHCPV6_STATUS_NOTONLINK;
1183                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1184                         notonlink = true;
1185                 }
1186
1187                 buf += ia_response_len;
1188                 buflen -= ia_response_len;
1189                 response_len += ia_response_len;
1190                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1191         }
1192
1193         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1194                         response_len + 6 < buflen) {
1195                 buf[0] = 0;
1196                 buf[1] = DHCPV6_OPT_STATUS;
1197                 buf[2] = 0;
1198                 buf[3] = 2;
1199                 buf[4] = 0;
1200                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1201                 response_len += 6;
1202         }
1203
1204         dhcpv6_write_statefile();
1205
1206 out:
1207         return response_len;
1208 }