src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19 #include "libubox/usock.h"
  20
  21 #include <time.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <stdio.h>
  25 #include <poll.h>
  26 #include <alloca.h>
  27 #include <resolv.h>
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <stdbool.h>
  33 #include <arpa/inet.h>
  34 #include <sys/timerfd.h>
  35
  36
  37 static void reconf_timer(struct uloop_timeout *event);
  38 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  39 static uint32_t serial = 0;
  40 static uint8_t statemd5[16];
  41
  42
  43 int dhcpv6_ia_init(void)
  44 {
  45         uloop_timeout_set(&reconf_event, 2000);
  46         return 0;
  47 }
  48
  49
  50 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  51 {
  52         if (c->managed_sock.fd.registered) {
  53                 ustream_free(&c->managed_sock.stream);
  54                 close(c->managed_sock.fd.fd);
  55         }
  56
  57         if (c->head.next)
  58                 list_del(&c->head);
  59
  60         free(c->managed);
  61         free(c->hostname);
  62         free(c);
  63 }
  64
  65
  66 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  67 {
  68         if (!enable && iface->ia_assignments.next) {
  69                 struct dhcpv6_assignment *c;
  70                 while (!list_empty(&iface->ia_assignments)) {
  71                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  72                         free_dhcpv6_assignment(c);
  73                 }
  74         }
  75
  76         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  77                 if (!iface->ia_assignments.next)
  78                         INIT_LIST_HEAD(&iface->ia_assignments);
  79
  80                 if (list_empty(&iface->ia_assignments)) {
  81                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  82                         if (!border) {
  83                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  84                                 return -1;
  85                         }
  86
  87                         border->length = 64;
  88                         list_add(&border->head, &iface->ia_assignments);
  89                 }
  90
  91                 // Parse static entries
  92                 struct lease *lease;
  93                 list_for_each_entry(lease, &leases, head) {
  94                         // Construct entry
  95                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
  96                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
  97                         if (!a) {
  98                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  99                                         iface->ifname);
 100                                 return -1;
 101                         }
 102
 103                         if (lease->dhcpv4_leasetime > 0)
 104                                 a->leasetime = lease->dhcpv4_leasetime;
 105
 106                         a->clid_len = duid_len;
 107                         a->length = 128;
 108                         if (lease->hostid) {
 109                                 a->assigned = lease->hostid;
 110                         } else {
 111                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 112                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 113                         }
 114                         odhcpd_urandom(a->key, sizeof(a->key));
 115                         memcpy(a->clid_data, lease->duid, lease->duid_len);
 116                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 117                         /* Static assignment */
 118                         a->flags |= OAF_STATIC;
 119                         /* Infinite valid */
 120                         a->valid_until = 0;
 121
 122                         // Assign to all interfaces
 123                         struct dhcpv6_assignment *c;
 124                         list_for_each_entry(c, &iface->ia_assignments, head) {
 125                                 if (c->length != 128 || c->assigned > a->assigned) {
 126                                         list_add_tail(&a->head, &c->head);
 127                                         break;
 128                                 } else if (c->assigned == a->assigned) {
 129                                         // Already an assignment with that number
 130                                         break;
 131                                 }
 132                         }
 133
 134                         if (a->head.next) {
 135                                 if (lease->hostname[0]) {
 136                                         free(a->hostname);
 137                                         a->hostname = strdup(lease->hostname);
 138                                 }
 139                         } else {
 140                                 free(a->hostname);
 141                                 free(a);
 142                         }
 143                 }
 144         }
 145         return 0;
 146 }
 147
 148
 149 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 150 {
 151         struct {
 152                 struct dhcpv6_client_header hdr;
 153                 uint16_t srvid_type;
 154                 uint16_t srvid_len;
 155                 uint16_t duid_type;
 156                 uint16_t hardware_type;
 157                 uint8_t mac[6];
 158                 uint16_t msg_type;
 159                 uint16_t msg_len;
 160                 uint8_t msg_id;
 161                 struct dhcpv6_auth_reconfigure auth;
 162                 uint16_t clid_type;
 163                 uint16_t clid_len;
 164                 uint8_t clid_data[128];
 165         } __attribute__((packed)) reconf_msg = {
 166                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 167                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 168                 .srvid_len = htons(10),
 169                 .duid_type = htons(3),
 170                 .hardware_type = htons(1),
 171                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 172                 .msg_len = htons(1),
 173                 .msg_id = DHCPV6_MSG_RENEW,
 174                 .auth = {htons(DHCPV6_OPT_AUTH),
 175                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 176                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 177                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 178                 .clid_len = htons(assign->clid_len),
 179                 .clid_data = {0},
 180         };
 181
 182         odhcpd_get_mac(iface, reconf_msg.mac);
 183         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 184         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 185
 186         md5_ctx_t md5;
 187         uint8_t secretbytes[64];
 188         memset(secretbytes, 0, sizeof(secretbytes));
 189         memcpy(secretbytes, assign->key, sizeof(assign->key));
 190
 191         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 192                 secretbytes[i] ^= 0x36;
 193
 194         md5_begin(&md5);
 195         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 196         md5_hash(iov.iov_base, iov.iov_len, &md5);
 197         md5_end(reconf_msg.auth.key, &md5);
 198
 199         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 200                 secretbytes[i] ^= 0x36;
 201                 secretbytes[i] ^= 0x5c;
 202         }
 203
 204         md5_begin(&md5);
 205         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 206         md5_hash(reconf_msg.auth.key, 16, &md5);
 207         md5_end(reconf_msg.auth.key, &md5);
 208
 209         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 210 }
 211
 212
 213 void dhcpv6_write_statefile(void)
 214 {
 215         md5_ctx_t md5;
 216         md5_begin(&md5);
 217
 218         if (config.dhcp_statefile) {
 219                 time_t now = odhcpd_time(), wall_time = time(NULL);
 220                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 221                 if (fd < 0)
 222                         return;
 223
 224                 lockf(fd, F_LOCK, 0);
 225                 if (ftruncate(fd, 0) < 0) {}
 226
 227                 FILE *fp = fdopen(fd, "w");
 228                 if (!fp) {
 229                         close(fd);
 230                         return;
 231                 }
 232
 233                 struct interface *iface;
 234                 list_for_each_entry(iface, &interfaces, head) {
 235                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 236                                 continue;
 237
 238                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 239                                 struct dhcpv6_assignment *c;
 240                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 241                                         if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
 242                                                 continue;
 243
 244                                         char ipbuf[INET6_ADDRSTRLEN];
 245                                         char leasebuf[512];
 246                                         char duidbuf[264];
 247                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 248
 249                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 250                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
 251                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 252                                                         (c->hostname ? c->hostname : "-"),
 253                                                         (c->valid_until > now ?
 254                                                                 (c->valid_until - now + wall_time) :
 255                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 256                                                         c->assigned, (unsigned)c->length);
 257
 258                                         struct in6_addr addr;
 259                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 260                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 261                                         size_t m = 0;
 262
 263                                         for (size_t i = 0; i < addrlen; ++i)
 264                                                 if (addrs[i].preferred > addrs[m].preferred ||
 265                                                                 (addrs[i].preferred == addrs[m].preferred &&
 266                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 267                                                         m = i;
 268
 269                                         for (size_t i = 0; i < addrlen; ++i) {
 270                                                 if (addrs[i].prefix > 96 || (!INFINITE_VALID(c->valid_until) && c->valid_until <= now) ||
 271                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 272                                                                                 addrs[i].prefix == 64))
 273                                                         continue;
 274
 275                                                 addr = addrs[i].addr;
 276                                                 if (c->length == 128)
 277                                                         addr.s6_addr32[3] = htonl(c->assigned);
 278                                                 else
 279                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 280
 281                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 282
 283                                                 if (c->length == 128 && c->hostname) {
 284                                                         fputs(ipbuf, fp);
 285
 286                                                         char b[256];
 287                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 288                                                                         iface->search, b, sizeof(b)) > 0)
 289                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 290
 291                                                         fprintf(fp, "\t%s\n", c->hostname);
 292                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 293                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 294                                                 }
 295
 296                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 297                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 298                                         }
 299                                         leasebuf[l - 1] = '\n';
 300                                         fwrite(leasebuf, 1, l, fp);
 301                                 }
 302                         }
 303
 304                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 305                                 struct dhcpv4_assignment *c;
 306                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 307                                         if (!(c->flags & OAF_BOUND))
 308                                                 continue;
 309
 310                                         char ipbuf[INET6_ADDRSTRLEN];
 311                                         char leasebuf[512];
 312                                         char duidbuf[16];
 313                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 314
 315                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 316                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
 317                                                         iface->ifname, duidbuf,
 318                                                         (c->hostname ? c->hostname : "-"),
 319                                                         (c->valid_until > now ?
 320                                                                 (c->valid_until - now + wall_time) :
 321                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 322                                                         c->addr);
 323
 324                                         struct in_addr addr = {htonl(c->addr)};
 325                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 326
 327                                         if (c->hostname[0]) {
 328                                                 fputs(ipbuf, fp);
 329
 330                                                 char b[256];
 331                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 332                                                                 iface->search, b, sizeof(b)) > 0)
 333                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 334
 335                                                 fprintf(fp, "\t%s\n", c->hostname);
 336                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 337                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 338                                         }
 339
 340                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 341                                         leasebuf[l - 1] = '\n';
 342                                         fwrite(leasebuf, 1, l, fp);
 343                                 }
 344                         }
 345                 }
 346
 347                 fclose(fp);
 348         }
 349
 350         uint8_t newmd5[16];
 351         md5_end(newmd5, &md5);
 352
 353         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 354                 memcpy(statemd5, newmd5, sizeof(statemd5));
 355                 char *argv[2] = {config.dhcp_cb, NULL};
 356                 if (!vfork()) {
 357                         execv(argv[0], argv);
 358                         _exit(128);
 359                 }
 360         }
 361 }
 362
 363
 364 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 365 {
 366         if (a->length > 64 || a->managed_size < 0)
 367                 return;
 368
 369         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 370         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 371
 372         for (size_t i = 0; i < addrlen; ++i) {
 373                 struct in6_addr prefix = addrs[i].addr;
 374                 prefix.s6_addr32[1] |= htonl(a->assigned);
 375                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 376                                 iface, &a->peer.sin6_addr, 1024, add);
 377         }
 378 }
 379
 380
 381 // More data was received from TCP connection
 382 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 383 {
 384         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 385         time_t now = odhcpd_time();
 386         bool first = c->managed_size < 0;
 387
 388         for (;;) {
 389                 int pending;
 390                 char *data = ustream_get_read_buf(s, &pending);
 391                 char *end = memmem(data, pending, "\n\n", 2);
 392
 393                 if (!end)
 394                         break;
 395
 396                 end += 2;
 397                 end[-1] = 0;
 398
 399                 c->managed_size = 0;
 400                 if (c->accept_reconf)
 401                         c->reconf_cnt = 1;
 402
 403                 char *saveptr;
 404                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 405                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 406                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 407
 408                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 409                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 410                                 continue;
 411
 412                         x = strtok_r(NULL, ",", &saveptr2);
 413                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 414                                 continue;
 415
 416                         x = strtok_r(NULL, ",", &saveptr2);
 417                         if (sscanf(x, "%u", &n->preferred) < 1)
 418                                 continue;
 419
 420                         x = strtok_r(NULL, ",", &saveptr2);
 421                         if (sscanf(x, "%u", &n->valid) < 1)
 422                                 continue;
 423
 424                         if (n->preferred > n->valid)
 425                                 continue;
 426
 427                         if (UINT32_MAX - now < n->preferred)
 428                                 n->preferred = UINT32_MAX;
 429                         else
 430                                 n->preferred += now;
 431
 432                         if (UINT32_MAX - now < n->valid)
 433                                 n->valid = UINT32_MAX;
 434                         else
 435                                 n->valid += now;
 436
 437                         n->dprefix = 0;
 438
 439                         ++c->managed_size;
 440                 }
 441
 442                 ustream_consume(s, end - data);
 443         }
 444
 445         if (first && c->managed_size == 0)
 446                 free_dhcpv6_assignment(c);
 447         else if (first)
 448                 c->valid_until = now + 150;
 449 }
 450
 451
 452 // TCP transmission has ended, either because of success or timeout or other error
 453 static void managed_handle_pd_done(struct ustream *s)
 454 {
 455         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 456         c->valid_until = odhcpd_time() + 15;
 457         c->managed_size = 0;
 458         if (c->accept_reconf)
 459                 c->reconf_cnt = 1;
 460 }
 461
 462
 463
 464 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 465 {
 466         struct dhcpv6_assignment *c;
 467
 468         if (iface->dhcpv6_pd_manager[0]) {
 469                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 470                 if (fd >= 0) {
 471                         char iaidbuf[298];
 472                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 473
 474                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 475                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 476                         ustream_fd_init(&assign->managed_sock, fd);
 477                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 478                                         iaidbuf, assign->iaid, assign->length);
 479                         ustream_write_pending(&assign->managed_sock.stream);
 480                         assign->managed_size = -1;
 481                         assign->valid_until = odhcpd_time() + 15;
 482                         list_add(&assign->head, &iface->ia_assignments);
 483
 484                         // Wait initial period of up to 250ms for immediate assignment
 485                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 486                         poll(&pfd, 1, 250);
 487                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 488
 489                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 490                                 return true;
 491                 }
 492
 493                 return false;
 494         } else if (iface->ia_addr_len < 1) {
 495                 return false;
 496         }
 497
 498         // Try honoring the hint first
 499         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 500         if (assign->assigned) {
 501                 list_for_each_entry(c, &iface->ia_assignments, head) {
 502                         if (c->length == 128 || c->length == 0)
 503                                 continue;
 504
 505                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 506                                 list_add_tail(&assign->head, &c->head);
 507                                 apply_lease(iface, assign, true);
 508                                 return true;
 509                         }
 510
 511                         if (c->assigned != 0)
 512                                 current = (c->assigned + (1 << (64 - c->length)));
 513                 }
 514         }
 515
 516         // Fallback to a variable assignment
 517         current = 1;
 518         list_for_each_entry(c, &iface->ia_assignments, head) {
 519                 if (c->length == 128 || c->length == 0)
 520                         continue;
 521
 522                 current = (current + asize) & (~asize);
 523                 if (current + asize < c->assigned) {
 524                         assign->assigned = current;
 525                         list_add_tail(&assign->head, &c->head);
 526                         apply_lease(iface, assign, true);
 527                         return true;
 528                 }
 529
 530                 if (c->assigned != 0)
 531                         current = (c->assigned + (1 << (64 - c->length)));
 532         }
 533
 534         return false;
 535 }
 536
 537
 538 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 539 {
 540         // Seed RNG with checksum of DUID
 541         uint32_t seed = 0;
 542         for (size_t i = 0; i < assign->clid_len; ++i)
 543                 seed += assign->clid_data[i];
 544         srand(seed);
 545
 546         // Try to assign up to 100x
 547         for (size_t i = 0; i < 100; ++i) {
 548                 uint32_t try;
 549                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 550
 551                 struct dhcpv6_assignment *c;
 552                 list_for_each_entry(c, &iface->ia_assignments, head) {
 553                         if (c->length == 0)
 554                                 continue;
 555
 556                         if (c->assigned > try || c->length != 128) {
 557                                 assign->assigned = try;
 558                                 list_add_tail(&assign->head, &c->head);
 559                                 return true;
 560                         } else if (c->assigned == try) {
 561                                 break;
 562                         }
 563                 }
 564         }
 565
 566         return false;
 567 }
 568
 569 void dhcpv6_ia_preupdate(struct interface *iface)
 570 {
 571         if (iface->dhcpv6 != RELAYD_SERVER)
 572                 return;
 573
 574         struct dhcpv6_assignment *c, *border = list_last_entry(
 575                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 576         list_for_each_entry(c, &iface->ia_assignments, head)
 577                 if (c != border && !iface->managed)
 578                         apply_lease(iface, c, false);
 579 }
 580
 581 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 582 {
 583         if (iface->dhcpv6 != RELAYD_SERVER)
 584                 return;
 585
 586         int minprefix = -1;
 587         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 588                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 589                                 iface->ia_addr[i].prefix < 64 &&
 590                                 iface->ia_addr[i].prefix > minprefix)
 591                         minprefix = iface->ia_addr[i].prefix;
 592         }
 593
 594         struct dhcpv6_assignment *border = list_last_entry(
 595                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 596         if (minprefix > 32 && minprefix <= 64)
 597                 border->assigned = 1U << (64 - minprefix);
 598         else
 599                 border->assigned = 0;
 600
 601         struct list_head reassign = LIST_HEAD_INIT(reassign);
 602         struct dhcpv6_assignment *c, *d;
 603         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 604                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
 605                                 c->managed_size)
 606                         continue;
 607
 608                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 609                         list_move(&c->head, &reassign);
 610                 else if (c != border)
 611                         apply_lease(iface, c, true);
 612
 613                 if (c->accept_reconf && c->reconf_cnt == 0) {
 614                         c->reconf_cnt = 1;
 615                         c->reconf_sent = now;
 616                         send_reconf(iface, c);
 617
 618                         // Leave all other assignments of that client alone
 619                         struct dhcpv6_assignment *a;
 620                         list_for_each_entry(a, &iface->ia_assignments, head)
 621                                 if (a != c && a->clid_len == c->clid_len &&
 622                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 623                                         c->reconf_cnt = INT_MAX;
 624                 }
 625         }
 626
 627         while (!list_empty(&reassign)) {
 628                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 629                 list_del(&c->head);
 630                 if (!assign_pd(iface, c)) {
 631                         c->assigned = 0;
 632                         list_add(&c->head, &iface->ia_assignments);
 633                 }
 634         }
 635
 636         dhcpv6_write_statefile();
 637 }
 638
 639
 640 static void reconf_timer(struct uloop_timeout *event)
 641 {
 642         time_t now = odhcpd_time();
 643         struct interface *iface;
 644         list_for_each_entry(iface, &interfaces, head) {
 645                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 646                         continue;
 647
 648                 struct dhcpv6_assignment *a, *n;
 649                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 650                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
 651                                 if ((a->length < 128 && a->clid_len > 0) ||
 652                                                 (a->length == 128 && a->clid_len == 0)) {
 653                                         list_del(&a->head);
 654                                         free_dhcpv6_assignment(a);
 655                                 }
 656                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 657                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 658                                 ++a->reconf_cnt;
 659                                 a->reconf_sent = now;
 660                                 send_reconf(iface, a);
 661                         }
 662                 }
 663         }
 664         uloop_timeout_set(event, 2000);
 665 }
 666
 667
 668 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 669                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 670                 struct interface *iface, bool request)
 671 {
 672         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 673                 return 0;
 674
 675         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 676         size_t datalen = sizeof(out);
 677         time_t now = odhcpd_time();
 678
 679         if (status) {
 680                 struct __attribute__((packed)) {
 681                         uint16_t type;
 682                         uint16_t len;
 683                         uint16_t value;
 684                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 685                                 htons(status)};
 686
 687                 memcpy(buf + datalen, &stat, sizeof(stat));
 688                 datalen += sizeof(stat);
 689         } else {
 690                 if (a) {
 691                         uint32_t leasetime;
 692                         if (a->leasetime > 0) {
 693                                 leasetime = a->leasetime;
 694                         } else {
 695                                 leasetime = iface->dhcpv4_leasetime;
 696                         }
 697                         if (leasetime == 0)
 698                                 leasetime = 3600;
 699                         else if (leasetime < 60)
 700                                 leasetime = 60;
 701
 702                         uint32_t pref = leasetime;
 703                         uint32_t valid = leasetime;
 704
 705                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 706                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 707                         size_t m = 0;
 708
 709                         for (size_t i = 0; i < addrlen; ++i)
 710                                 if (addrs[i].preferred > addrs[m].preferred ||
 711                                                 (addrs[i].preferred == addrs[m].preferred &&
 712                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 713                                         m = i;
 714
 715                         for (size_t i = 0; i < addrlen; ++i) {
 716                                 uint32_t prefix_pref = addrs[i].preferred;
 717                                 uint32_t prefix_valid = addrs[i].valid;
 718
 719                                 if (addrs[i].prefix > 96 ||
 720                                                 addrs[i].preferred <= (uint32_t)now)
 721                                         continue;
 722
 723                                 if (prefix_pref != UINT32_MAX)
 724                                         prefix_pref -= now;
 725
 726                                 if (prefix_valid != UINT32_MAX)
 727                                         prefix_valid -= now;
 728
 729                                 if (a->length < 128) {
 730                                         struct dhcpv6_ia_prefix p = {
 731                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 732                                                 .len = htons(sizeof(p) - 4),
 733                                                 .preferred = htonl(prefix_pref),
 734                                                 .valid = htonl(prefix_valid),
 735                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 736                                                 .addr = addrs[i].addr
 737                                         };
 738                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 739
 740                                         size_t entrlen = sizeof(p) - 4;
 741
 742                                         if (datalen + entrlen + 4 > buflen ||
 743                                                         (a->assigned == 0 && a->managed_size == 0) ||
 744                                                         (!a->managed_size && a->length <= addrs[i].prefix))
 745                                                 continue;
 746
 747                                         memcpy(buf + datalen, &p, sizeof(p));
 748                                         datalen += entrlen + 4;
 749                                 } else {
 750                                         struct dhcpv6_ia_addr n = {
 751                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 752                                                 .len = htons(sizeof(n) - 4),
 753                                                 .addr = addrs[i].addr,
 754                                                 .preferred = htonl(prefix_pref),
 755                                                 .valid = htonl(prefix_valid)
 756                                         };
 757                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 758                                         size_t entrlen = sizeof(n) - 4;
 759
 760                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 761                                                         addrs[i].prefix <= 64)
 762                                                 continue;
 763
 764                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 765                                                 continue;
 766
 767                                         memcpy(buf + datalen, &n, sizeof(n));
 768                                         datalen += entrlen + 4;
 769                                 }
 770
 771                                 // Calculate T1 / T2 based on non-deprecated addresses
 772                                 if (prefix_pref > 0) {
 773                                         if (prefix_pref < pref)
 774                                                 pref = prefix_pref;
 775
 776                                         if (prefix_valid < valid)
 777                                                 valid = prefix_valid;
 778                                 }
 779                         }
 780
 781                         if (!INFINITE_VALID(a->valid_until))
 782                                 /* UINT32_MAX is considered as infinite leasetime */
 783                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 784
 785                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
 786                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 787
 788                         if (!out.t1)
 789                                 out.t1 = htonl(1);
 790
 791                         if (!out.t2)
 792                                 out.t2 = htonl(1);
 793                 }
 794
 795                 if (!request) {
 796                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 797                         uint16_t otype, olen;
 798                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 799                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 800                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 801                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 802                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 803                                         continue;
 804
 805                                 bool found = false;
 806                                 if (a) {
 807                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 808                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 809
 810                                         for (size_t i = 0; i < addrlen; ++i) {
 811                                                 if (addrs[i].prefix > 96 ||
 812                                                                 addrs[i].preferred <= (uint32_t)now)
 813                                                         continue;
 814
 815                                                 struct in6_addr addr = addrs[i].addr;
 816                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 817                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 818
 819                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 820                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 821                                                                 found = true;
 822                                                 } else {
 823                                                         addr.s6_addr32[3] = htonl(a->assigned);
 824
 825                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 826                                                                 found = true;
 827                                                 }
 828                                         }
 829                                 }
 830
 831                                 if (!found) {
 832                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 833                                                 struct dhcpv6_ia_prefix inv = {
 834                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 835                                                         .len = htons(sizeof(inv) - 4),
 836                                                         .preferred = 0,
 837                                                         .valid = 0,
 838                                                         .prefix = p->prefix,
 839                                                         .addr = p->addr
 840                                                 };
 841
 842                                                 if (datalen + sizeof(inv) > buflen)
 843                                                         continue;
 844
 845                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 846                                                 datalen += sizeof(inv);
 847                                         } else {
 848                                                 struct dhcpv6_ia_addr inv = {
 849                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 850                                                         .len = htons(sizeof(inv) - 4),
 851                                                         .addr = n->addr,
 852                                                         .preferred = 0,
 853                                                         .valid = 0
 854                                                 };
 855
 856                                                 if (datalen + sizeof(inv) > buflen)
 857                                                         continue;
 858
 859                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 860                                                 datalen += sizeof(inv);
 861                                         }
 862                                 }
 863                         }
 864                 }
 865         }
 866
 867         out.len = htons(datalen - 4);
 868         memcpy(buf, &out, sizeof(out));
 869         return datalen;
 870 }
 871
 872
 873 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 874                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 875 {
 876         const char *type = "UNKNOWN";
 877         const char *status = "UNKNOWN";
 878
 879         if (msgtype == DHCPV6_MSG_RENEW)
 880                 return;
 881
 882         switch (msgtype) {
 883         case DHCPV6_MSG_SOLICIT:
 884                 type = "SOLICIT";
 885                 break;
 886         case DHCPV6_MSG_REQUEST:
 887                 type = "REQUEST";
 888                 break;
 889         case DHCPV6_MSG_CONFIRM:
 890                 type = "CONFIRM";
 891                 break;
 892         case DHCPV6_MSG_RENEW:
 893                 type = "RENEW";
 894                 break;
 895         case DHCPV6_MSG_REBIND:
 896                 type = "REBIND";
 897                 break;
 898         case DHCPV6_MSG_RELEASE:
 899                 type = "RELEASE";
 900                 break;
 901         case DHCPV6_MSG_DECLINE:
 902                 type = "DECLINE";
 903                 break;
 904         }
 905
 906         switch (code) {
 907         case DHCPV6_STATUS_OK:
 908                 status = "ok";
 909                 break;
 910         case DHCPV6_STATUS_NOADDRSAVAIL:
 911                 status = "no addresses available";
 912                 break;
 913         case DHCPV6_STATUS_NOBINDING:
 914                 status = "no binding";
 915                 break;
 916         case DHCPV6_STATUS_NOTONLINK:
 917                 status = "not on-link";
 918                 break;
 919         case DHCPV6_STATUS_NOPREFIXAVAIL:
 920                 status = "no prefix available";
 921                 break;
 922         }
 923
 924         char leasebuf[256] = "";
 925
 926         if (a) {
 927                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 928                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 929                 size_t lbsize = 0;
 930                 char addrbuf[INET6_ADDRSTRLEN];
 931
 932                 for (size_t i = 0; i < addrlen; ++i) {
 933                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 934                                 continue;
 935
 936                         struct in6_addr addr = addrs[i].addr;
 937                         int prefix = a->managed ? addrs[i].prefix : a->length;
 938                         if (prefix == 128)
 939                                 addr.s6_addr32[3] = htonl(a->assigned);
 940                         else
 941                                 addr.s6_addr32[1] |= htonl(a->assigned);
 942
 943                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 944                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 945                 }
 946         }
 947
 948         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 949                         duidbuf, iface->ifname, status, leasebuf);
 950 }
 951
 952
 953
 954 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 955                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 956 {
 957         time_t now = odhcpd_time();
 958         size_t response_len = 0;
 959         const struct dhcpv6_client_header *hdr = data;
 960         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 961         uint16_t otype, olen;
 962
 963         // Find and parse client-id and hostname
 964         bool accept_reconf = false;
 965         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 966         char hostname[256];
 967         size_t hostname_len = 0;
 968         bool notonlink = false;
 969         char duidbuf[261];
 970
 971         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 972                 if (otype == DHCPV6_OPT_CLIENTID) {
 973                         clid_data = odata;
 974                         clid_len = olen;
 975
 976                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 977                                 memcpy(mac, &odata[8], sizeof(mac));
 978                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 979                                 memcpy(mac, &odata[4], sizeof(mac));
 980
 981                         if (olen <= 130)
 982                                 odhcpd_hexlify(duidbuf, odata, olen);
 983                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 984                         uint8_t fqdn_buf[256];
 985                         memcpy(fqdn_buf, odata, olen);
 986                         fqdn_buf[olen++] = 0;
 987
 988                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 989                                 hostname_len = strcspn(hostname, ".");
 990                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 991                         accept_reconf = true;
 992                 }
 993         }
 994
 995         if (!clid_data || !clid_len || clid_len > 130)
 996                 goto out;
 997
 998         struct dhcpv6_assignment *first = NULL;
 999         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1000                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1001                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1002                 bool ia_addr_present = false;
1003                 if (!is_pd && !is_na)
1004                         continue;
1005
1006                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1007                 size_t ia_response_len = 0;
1008                 uint8_t reqlen = (is_pd) ? 62 : 128;
1009                 uint32_t reqhint = 0;
1010
1011                 // Parse request hint for IA-PD
1012                 if (is_pd) {
1013                         uint8_t *sdata;
1014                         uint16_t stype, slen;
1015                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1016                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1017                                         continue;
1018
1019                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1020                                 if (p->prefix) {
1021                                         reqlen = p->prefix;
1022                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1023                                         if (reqlen > 32 && reqlen <= 64)
1024                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1025                                 }
1026                         }
1027
1028                         if (reqlen > 64)
1029                                 reqlen = 64;
1030                 } else if (is_na) {
1031                         uint8_t *sdata;
1032                         uint16_t stype, slen;
1033                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1034                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1035                                         continue;
1036
1037                                 ia_addr_present = true;
1038                         }
1039                 }
1040
1041                 // Find assignment
1042                 struct dhcpv6_assignment *c, *a = NULL;
1043                 list_for_each_entry(c, &iface->ia_assignments, head) {
1044                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1045                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1046                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1047                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1048                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1049                                 a = c;
1050
1051                                 // Reset state
1052                                 apply_lease(iface, a, false);
1053                                 memcpy(a->clid_data, clid_data, clid_len);
1054                                 a->clid_len = clid_len;
1055                                 a->iaid = ia->iaid;
1056                                 a->peer = *addr;
1057                                 a->reconf_cnt = 0;
1058                                 a->reconf_sent = 0;
1059                                 break;
1060                         }
1061                 }
1062
1063                 // Generic message handling
1064                 uint16_t status = DHCPV6_STATUS_OK;
1065                 if (a && a->managed_size < 0) {
1066                         return -1;
1067                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1068                         bool assigned = !!a;
1069
1070                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1071                                 a = calloc(1, sizeof(*a) + clid_len);
1072                                 if (a) {
1073                                         a->clid_len = clid_len;
1074                                         a->iaid = ia->iaid;
1075                                         a->length = reqlen;
1076                                         a->peer = *addr;
1077                                         a->assigned = reqhint;
1078                                         // Set valid time to current time indicating
1079                                         // assignment is not having infinite lifetime
1080                                         a->valid_until = now;
1081
1082                                         if (first)
1083                                                 memcpy(a->key, first->key, sizeof(a->key));
1084                                         else
1085                                                 odhcpd_urandom(a->key, sizeof(a->key));
1086                                         memcpy(a->clid_data, clid_data, clid_len);
1087
1088                                         if (is_pd)
1089                                                 while (!(assigned = assign_pd(iface, a)) &&
1090                                                                 !a->managed_size && ++a->length <= 64);
1091                                         else
1092                                                 assigned = assign_na(iface, a);
1093
1094                                         if (a->managed_size && !assigned)
1095                                                 return -1;
1096                                 }
1097                         }
1098
1099                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1100                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1101                         } else if (assigned && !first) { //
1102                                 size_t handshake_len = 4;
1103                                 buf[0] = 0;
1104                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1105                                 buf[2] = 0;
1106                                 buf[3] = 0;
1107
1108                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1109                                         struct dhcpv6_auth_reconfigure auth = {
1110                                                 htons(DHCPV6_OPT_AUTH),
1111                                                 htons(sizeof(auth) - 4),
1112                                                 3, 1, 0,
1113                                                 {htonl(time(NULL)), htonl(++serial)},
1114                                                 1,
1115                                                 {0}
1116                                         };
1117                                         memcpy(auth.key, a->key, sizeof(a->key));
1118                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1119                                         handshake_len += sizeof(auth);
1120                                 }
1121
1122                                 buf += handshake_len;
1123                                 buflen -= handshake_len;
1124                                 response_len += handshake_len;
1125
1126                                 first = a;
1127                         }
1128
1129                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1130
1131                         // Was only a solicitation: mark binding for removal
1132                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1133                                 a->flags &= ~OAF_BOUND;
1134
1135                                 if (!(a->flags & OAF_STATIC))
1136                                         a->valid_until = now;
1137                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1138                                 if (hostname_len > 0) {
1139                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1140                                         if (a->hostname) {
1141                                                 memcpy(a->hostname, hostname, hostname_len);
1142                                                 a->hostname[hostname_len] = 0;
1143                                         }
1144                                 }
1145                                 a->accept_reconf = accept_reconf;
1146                                 a->flags |= OAF_BOUND;
1147                                 apply_lease(iface, a, true);
1148                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1149                                 free_dhcpv6_assignment(a);
1150                         }
1151                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1152                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1153                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1154                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1155                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1156                                 status = DHCPV6_STATUS_NOBINDING;
1157                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1158                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1159                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1160                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1161                                 if (a) {
1162                                         a->flags |= OAF_BOUND;
1163                                         apply_lease(iface, a, true);
1164                                 }
1165                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1166                                 if (!(a->flags & OAF_STATIC))
1167                                         a->valid_until = now - 1;
1168
1169                                 a->flags &= ~OAF_BOUND;
1170                                 apply_lease(iface, a, false);
1171                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1172                                 a->flags &= ~OAF_BOUND;
1173
1174                                 if (!(a->flags & OAF_STATIC)) {
1175                                         a->clid_len = 0;
1176                                         a->valid_until = now + 3600; // Block address for 1h
1177                                 }
1178                         }
1179                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1180                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1181                         status = DHCPV6_STATUS_NOTONLINK;
1182                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1183                         notonlink = true;
1184                 }
1185
1186                 buf += ia_response_len;
1187                 buflen -= ia_response_len;
1188                 response_len += ia_response_len;
1189                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1190         }
1191
1192         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1193                         response_len + 6 < buflen) {
1194                 buf[0] = 0;
1195                 buf[1] = DHCPV6_OPT_STATUS;
1196                 buf[2] = 0;
1197                 buf[3] = 2;
1198                 buf[4] = 0;
1199                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1200                 response_len += 6;
1201         }
1202
1203         dhcpv6_write_statefile();
1204
1205 out:
1206         return response_len;
1207 }