src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19 #include "libubox/usock.h"
  20
  21 #include <time.h>
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <stdio.h>
  25 #include <poll.h>
  26 #include <alloca.h>
  27 #include <resolv.h>
  28 #include <limits.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <stdbool.h>
  33 #include <arpa/inet.h>
  34 #include <sys/timerfd.h>
  35
  36
  37 static void update(struct interface *iface);
  38 static void reconf_timer(struct uloop_timeout *event);
  39 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  40 static uint32_t serial = 0;
  41 static uint8_t statemd5[16];
  42
  43
  44 int dhcpv6_ia_init(void)
  45 {
  46         uloop_timeout_set(&reconf_event, 2000);
  47         return 0;
  48 }
  49
  50
  51 void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
  52 {
  53         if (c->managed_sock.fd.registered) {
  54                 ustream_free(&c->managed_sock.stream);
  55                 close(c->managed_sock.fd.fd);
  56         }
  57
  58         if (c->head.next)
  59                 list_del(&c->head);
  60
  61         free(c->managed);
  62         free(c->hostname);
  63         free(c->classes);
  64         free(c);
  65 }
  66
  67
  68 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  69 {
  70         if (!enable && iface->ia_assignments.next) {
  71                 struct dhcpv6_assignment *c;
  72                 while (!list_empty(&iface->ia_assignments)) {
  73                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  74                         free_dhcpv6_assignment(c);
  75                 }
  76         }
  77
  78         if (iface->dhcpv6 == RELAYD_SERVER) {
  79                 if (!iface->ia_assignments.next)
  80                         INIT_LIST_HEAD(&iface->ia_assignments);
  81
  82                 if (list_empty(&iface->ia_assignments)) {
  83                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  84                         if (!border) {
  85                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  86                                 return -1;
  87                         }
  88
  89                         border->length = 64;
  90                         list_add(&border->head, &iface->ia_assignments);
  91                 }
  92
  93                 update(iface);
  94
  95                 // Parse static entries
  96                 struct lease *lease;
  97                 list_for_each_entry(lease, &leases, head) {
  98                         // Construct entry
  99                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
 100                         if (!a) {
 101                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
 102                                         iface->ifname);
 103                                 return -1;
 104                         }
 105
 106                         a->clid_len = lease->duid_len;
 107                         a->length = 128;
 108                         if (lease->hostid) {
 109                                 a->assigned = lease->hostid;
 110                         } else {
 111                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 112                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 113                         }
 114                         odhcpd_urandom(a->key, sizeof(a->key));
 115                         memcpy(a->clid_data, lease->duid, a->clid_len);
 116                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 117
 118                         // Assign to all interfaces
 119                         struct dhcpv6_assignment *c;
 120                         list_for_each_entry(c, &iface->ia_assignments, head) {
 121                                 if (c->length != 128 || c->assigned > a->assigned) {
 122                                         list_add_tail(&a->head, &c->head);
 123                                         break;
 124                                 } else if (c->assigned == a->assigned) {
 125                                         // Already an assignment with that number
 126                                         break;
 127                                 }
 128                         }
 129
 130                         if (a->head.next) {
 131                                 if (lease->hostname[0]) {
 132                                         free(a->hostname);
 133                                         a->hostname = strdup(lease->hostname);
 134                                 }
 135                         } else {
 136                                 free(a->classes);
 137                                 free(a->hostname);
 138                                 free(a);
 139                         }
 140                 }
 141         }
 142         return 0;
 143 }
 144
 145
 146 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 147 {
 148         struct {
 149                 struct dhcpv6_client_header hdr;
 150                 uint16_t srvid_type;
 151                 uint16_t srvid_len;
 152                 uint16_t duid_type;
 153                 uint16_t hardware_type;
 154                 uint8_t mac[6];
 155                 uint16_t msg_type;
 156                 uint16_t msg_len;
 157                 uint8_t msg_id;
 158                 struct dhcpv6_auth_reconfigure auth;
 159                 uint16_t clid_type;
 160                 uint16_t clid_len;
 161                 uint8_t clid_data[128];
 162         } __attribute__((packed)) reconf_msg = {
 163                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 164                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 165                 .srvid_len = htons(10),
 166                 .duid_type = htons(3),
 167                 .hardware_type = htons(1),
 168                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 169                 .msg_len = htons(1),
 170                 .msg_id = DHCPV6_MSG_RENEW,
 171                 .auth = {htons(DHCPV6_OPT_AUTH),
 172                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 173                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 174                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 175                 .clid_len = htons(assign->clid_len),
 176                 .clid_data = {0},
 177         };
 178
 179         odhcpd_get_mac(iface, reconf_msg.mac);
 180         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 181         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 182
 183         md5_ctx_t md5;
 184         uint8_t secretbytes[64];
 185         memset(secretbytes, 0, sizeof(secretbytes));
 186         memcpy(secretbytes, assign->key, sizeof(assign->key));
 187
 188         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 189                 secretbytes[i] ^= 0x36;
 190
 191         md5_begin(&md5);
 192         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 193         md5_hash(iov.iov_base, iov.iov_len, &md5);
 194         md5_end(reconf_msg.auth.key, &md5);
 195
 196         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 197                 secretbytes[i] ^= 0x36;
 198                 secretbytes[i] ^= 0x5c;
 199         }
 200
 201         md5_begin(&md5);
 202         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 203         md5_hash(reconf_msg.auth.key, 16, &md5);
 204         md5_end(reconf_msg.auth.key, &md5);
 205
 206         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 207 }
 208
 209
 210 void dhcpv6_write_statefile(void)
 211 {
 212         md5_ctx_t md5;
 213         md5_begin(&md5);
 214
 215         if (config.dhcp_statefile) {
 216                 time_t now = odhcpd_time(), wall_time = time(NULL);
 217                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 218                 if (fd < 0)
 219                         return;
 220
 221                 lockf(fd, F_LOCK, 0);
 222                 ftruncate(fd, 0);
 223
 224                 FILE *fp = fdopen(fd, "w");
 225                 if (!fp) {
 226                         close(fd);
 227                         return;
 228                 }
 229
 230                 struct interface *iface;
 231                 list_for_each_entry(iface, &interfaces, head) {
 232                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 233                                 continue;
 234
 235                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 236                                 struct dhcpv6_assignment *c;
 237                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 238                                         if (c->clid_len == 0 || c->managed_size < 0)
 239                                                 continue;
 240
 241                                         char ipbuf[INET6_ADDRSTRLEN];
 242                                         char leasebuf[512];
 243                                         char duidbuf[264];
 244                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 245
 246                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 247                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 248                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 249                                                         (c->hostname ? c->hostname : "-"),
 250                                                         (unsigned)(c->valid_until > now ?
 251                                                                         (c->valid_until - now + wall_time) : 0),
 252                                                         c->assigned, (unsigned)c->length);
 253
 254                                         struct in6_addr addr;
 255                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 256                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 257                                         size_t m = 0;
 258
 259                                         for (size_t i = 0; i < addrlen; ++i)
 260                                                 if (addrs[i].preferred > addrs[m].preferred ||
 261                                                                 (addrs[i].preferred == addrs[m].preferred &&
 262                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 263                                                         m = i;
 264
 265                                         for (size_t i = 0; i < addrlen; ++i) {
 266                                                 if (addrs[i].prefix > 96 || c->valid_until <= now ||
 267                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m))
 268                                                         continue;
 269
 270                                                 addr = addrs[i].addr;
 271                                                 if (c->length == 128)
 272                                                         addr.s6_addr32[3] = htonl(c->assigned);
 273                                                 else
 274                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 275
 276                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 277
 278                                                 if (c->length == 128 && c->hostname) {
 279                                                         fputs(ipbuf, fp);
 280
 281                                                         char b[256];
 282                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 283                                                                         iface->search, b, sizeof(b)) > 0)
 284                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 285
 286                                                         fprintf(fp, "\t%s\n", c->hostname);
 287                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 288                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 289                                                 }
 290
 291                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 292                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 293                                         }
 294                                         leasebuf[l - 1] = '\n';
 295                                         fwrite(leasebuf, 1, l, fp);
 296                                 }
 297                         }
 298
 299                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 300                                 struct dhcpv4_assignment *c;
 301                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 302                                         char ipbuf[INET6_ADDRSTRLEN];
 303                                         char leasebuf[512];
 304                                         char duidbuf[16];
 305                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 306
 307                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 308                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 309                                                         iface->ifname, duidbuf,
 310                                                         (c->hostname ? c->hostname : "-"),
 311                                                         (unsigned)(c->valid_until > now ?
 312                                                                         (c->valid_until - now + wall_time) : 0),
 313                                                         c->addr);
 314
 315                                         struct in_addr addr = {htonl(c->addr)};
 316                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 317
 318                                         if (c->hostname[0]) {
 319                                                 fputs(ipbuf, fp);
 320
 321                                                 char b[256];
 322                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 323                                                                 iface->search, b, sizeof(b)) > 0)
 324                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 325
 326                                                 fprintf(fp, "\t%s\n", c->hostname);
 327                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 328                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 329                                         }
 330
 331                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 332                                         leasebuf[l - 1] = '\n';
 333                                         fwrite(leasebuf, 1, l, fp);
 334                                 }
 335                         }
 336                 }
 337
 338                 fclose(fp);
 339         }
 340
 341         uint8_t newmd5[16];
 342         md5_end(newmd5, &md5);
 343
 344         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 345                 memcpy(statemd5, newmd5, sizeof(statemd5));
 346                 char *argv[2] = {config.dhcp_cb, NULL};
 347                 if (!vfork()) {
 348                         execv(argv[0], argv);
 349                         _exit(128);
 350                 }
 351         }
 352 }
 353
 354
 355 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 356 {
 357         if (a->length > 64 || a->managed_size < 0)
 358                 return;
 359
 360         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 361         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 362
 363         for (size_t i = 0; i < addrlen; ++i) {
 364                 struct in6_addr prefix = addrs[i].addr;
 365                 prefix.s6_addr32[1] |= htonl(a->assigned);
 366                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 367                                 iface, &a->peer.sin6_addr, add);
 368         }
 369 }
 370
 371
 372 // More data was received from TCP connection
 373 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 374 {
 375         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 376         time_t now = odhcpd_time();
 377         bool first = c->managed_size < 0;
 378
 379         for (;;) {
 380                 int pending;
 381                 char *data = ustream_get_read_buf(s, &pending);
 382                 char *end = memmem(data, pending, "\n\n", 2);
 383
 384                 if (!end)
 385                         break;
 386
 387                 end += 2;
 388                 end[-1] = 0;
 389
 390                 c->managed_size = 0;
 391                 if (c->accept_reconf)
 392                         c->reconf_cnt = 1;
 393
 394                 char *saveptr;
 395                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 396                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 397                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 398
 399                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 400                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 401                                 continue;
 402
 403                         x = strtok_r(NULL, ",", &saveptr2);
 404                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 405                                 continue;
 406
 407                         x = strtok_r(NULL, ",", &saveptr2);
 408                         if (sscanf(x, "%u", &n->preferred) < 1)
 409                                 continue;
 410
 411                         x = strtok_r(NULL, ",", &saveptr2);
 412                         if (sscanf(x, "%u", &n->valid) < 1)
 413                                 continue;
 414
 415                         if (n->preferred > n->valid)
 416                                 continue;
 417
 418                         if (UINT32_MAX - now < n->preferred)
 419                                 n->preferred = UINT32_MAX;
 420                         else
 421                                 n->preferred += now;
 422
 423                         if (UINT32_MAX - now < n->valid)
 424                                 n->valid = UINT32_MAX;
 425                         else
 426                                 n->valid += now;
 427
 428                         n->dprefix = 0;
 429
 430                         ++c->managed_size;
 431                 }
 432
 433                 ustream_consume(s, end - data);
 434         }
 435
 436         if (first && c->managed_size == 0)
 437                 free_dhcpv6_assignment(c);
 438         else if (first)
 439                 c->valid_until = now + 150;
 440 }
 441
 442
 443 // TCP transmission has ended, either because of success or timeout or other error
 444 static void managed_handle_pd_done(struct ustream *s)
 445 {
 446         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 447         c->valid_until = odhcpd_time() + 15;
 448         c->managed_size = 0;
 449         if (c->accept_reconf)
 450                 c->reconf_cnt = 1;
 451 }
 452
 453
 454
 455 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 456 {
 457         struct dhcpv6_assignment *c;
 458
 459         if (iface->dhcpv6_pd_manager[0]) {
 460                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 461                 if (fd >= 0) {
 462                         char iaidbuf[298];
 463                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 464
 465                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 466                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 467                         ustream_fd_init(&assign->managed_sock, fd);
 468                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 469                                         iaidbuf, assign->iaid, assign->length);
 470                         ustream_write_pending(&assign->managed_sock.stream);
 471                         assign->managed_size = -1;
 472                         assign->valid_until = odhcpd_time() + 15;
 473                         list_add(&assign->head, &iface->ia_assignments);
 474
 475                         // Wait initial period of up to 250ms for immediate assignment
 476                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 477                         poll(&pfd, 1, 250);
 478                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 479
 480                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 481                                 return true;
 482                 }
 483
 484                 return false;
 485         } else if (iface->ia_addr_len < 1) {
 486                 return false;
 487         }
 488
 489         // Try honoring the hint first
 490         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 491         if (assign->assigned) {
 492                 list_for_each_entry(c, &iface->ia_assignments, head) {
 493                         if (c->length == 128 || c->length == 0)
 494                                 continue;
 495
 496                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 497                                 list_add_tail(&assign->head, &c->head);
 498                                 apply_lease(iface, assign, true);
 499                                 return true;
 500                         }
 501
 502                         if (c->assigned != 0)
 503                                 current = (c->assigned + (1 << (64 - c->length)));
 504                 }
 505         }
 506
 507         // Fallback to a variable assignment
 508         current = 1;
 509         list_for_each_entry(c, &iface->ia_assignments, head) {
 510                 if (c->length == 128 || c->length == 0)
 511                         continue;
 512
 513                 current = (current + asize) & (~asize);
 514                 if (current + asize < c->assigned) {
 515                         assign->assigned = current;
 516                         list_add_tail(&assign->head, &c->head);
 517                         apply_lease(iface, assign, true);
 518                         return true;
 519                 }
 520
 521                 if (c->assigned != 0)
 522                         current = (c->assigned + (1 << (64 - c->length)));
 523         }
 524
 525         return false;
 526 }
 527
 528
 529 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 530 {
 531         // Seed RNG with checksum of DUID
 532         uint32_t seed = 0;
 533         for (size_t i = 0; i < assign->clid_len; ++i)
 534                 seed += assign->clid_data[i];
 535         srand(seed);
 536
 537         // Try to assign up to 100x
 538         for (size_t i = 0; i < 100; ++i) {
 539                 uint32_t try;
 540                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 541
 542                 struct dhcpv6_assignment *c;
 543                 list_for_each_entry(c, &iface->ia_assignments, head) {
 544                         if (c->length == 0)
 545                                 continue;
 546
 547                         if (c->assigned > try || c->length != 128) {
 548                                 assign->assigned = try;
 549                                 list_add_tail(&assign->head, &c->head);
 550                                 return true;
 551                         } else if (c->assigned == try) {
 552                                 break;
 553                         }
 554                 }
 555         }
 556
 557         return false;
 558 }
 559
 560
 561 static int prefixcmp(const void *va, const void *vb)
 562 {
 563         const struct odhcpd_ipaddr *a = va, *b = vb;
 564         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 565         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 566         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 567 }
 568
 569
 570 static void update(struct interface *iface)
 571 {
 572         struct odhcpd_ipaddr addr[8];
 573         memset(addr, 0, sizeof(addr));
 574         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 575
 576         if (len < 0)
 577                 return;
 578
 579         qsort(addr, len, sizeof(*addr), prefixcmp);
 580
 581         time_t now = odhcpd_time();
 582         int minprefix = -1;
 583
 584         for (int i = 0; i < len; ++i) {
 585                 if (addr[i].preferred > 0 && addr[i].prefix > minprefix)
 586                         minprefix = addr[i].prefix;
 587
 588                 addr[i].addr.s6_addr32[3] = 0;
 589
 590                 if (addr[i].preferred < UINT32_MAX - now)
 591                         addr[i].preferred += now;
 592
 593                 if (addr[i].valid < UINT32_MAX - now)
 594                         addr[i].valid += now;
 595         }
 596
 597         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 598         border->assigned = 1 << (64 - minprefix);
 599
 600         bool change = len != (int)iface->ia_addr_len;
 601         for (int i = 0; !change && i < len; ++i)
 602                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 603                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 604                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 605                                 (addr[i].valid > (uint32_t)now + 7200) !=
 606                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 607                         change = true;
 608
 609         if (change) {
 610                 struct dhcpv6_assignment *c;
 611                 list_for_each_entry(c, &iface->ia_assignments, head)
 612                         if (c != border && !iface->managed)
 613                                 apply_lease(iface, c, false);
 614         }
 615
 616         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 617         iface->ia_addr_len = len;
 618
 619         if (change) { // Addresses / prefixes have changed
 620                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 621                 struct dhcpv6_assignment *c, *d;
 622                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 623                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 624                                 continue;
 625
 626                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 627                                 list_move(&c->head, &reassign);
 628                         else if (c != border)
 629                                 apply_lease(iface, c, true);
 630
 631                         if (c->accept_reconf && c->reconf_cnt == 0) {
 632                                 c->reconf_cnt = 1;
 633                                 c->reconf_sent = now;
 634                                 send_reconf(iface, c);
 635
 636                                 // Leave all other assignments of that client alone
 637                                 struct dhcpv6_assignment *a;
 638                                 list_for_each_entry(a, &iface->ia_assignments, head)
 639                                         if (a != c && a->clid_len == c->clid_len &&
 640                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 641                                                 c->reconf_cnt = INT_MAX;
 642                         }
 643                 }
 644
 645                 while (!list_empty(&reassign)) {
 646                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 647                         list_del(&c->head);
 648                         if (!assign_pd(iface, c)) {
 649                                 c->assigned = 0;
 650                                 list_add(&c->head, &iface->ia_assignments);
 651                         }
 652                 }
 653
 654                 dhcpv6_write_statefile();
 655         }
 656 }
 657
 658
 659 static void reconf_timer(struct uloop_timeout *event)
 660 {
 661         time_t now = odhcpd_time();
 662         struct interface *iface;
 663         list_for_each_entry(iface, &interfaces, head) {
 664                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 665                         continue;
 666
 667                 struct dhcpv6_assignment *a, *n;
 668                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 669                         if (a->valid_until < now) {
 670                                 if ((a->length < 128 && a->clid_len > 0) ||
 671                                                 (a->length == 128 && a->clid_len == 0)) {
 672                                         list_del(&a->head);
 673                                         free_dhcpv6_assignment(a);
 674                                 }
 675                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 676                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 677                                 ++a->reconf_cnt;
 678                                 a->reconf_sent = now;
 679                                 send_reconf(iface, a);
 680                         }
 681                 }
 682         }
 683         uloop_timeout_set(event, 2000);
 684 }
 685
 686
 687 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 688                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 689                 struct interface *iface, bool request)
 690 {
 691         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 692                 return 0;
 693
 694         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 695         size_t datalen = sizeof(out);
 696         time_t now = odhcpd_time();
 697
 698         if (status) {
 699                 struct __attribute__((packed)) {
 700                         uint16_t type;
 701                         uint16_t len;
 702                         uint16_t value;
 703                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 704                                 htons(status)};
 705
 706                 memcpy(buf + datalen, &stat, sizeof(stat));
 707                 datalen += sizeof(stat);
 708         } else {
 709                 if (a) {
 710                         uint32_t leasetime = iface->dhcpv4_leasetime;
 711                         if (leasetime == 0)
 712                                 leasetime = 3600;
 713                         else if (leasetime < 60)
 714                                 leasetime = 60;
 715
 716                         uint32_t pref = leasetime;
 717                         uint32_t valid = leasetime;
 718
 719                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 720                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 721                         size_t m = 0;
 722
 723                         for (size_t i = 0; i < addrlen; ++i)
 724                                 if (addrs[i].preferred > addrs[m].preferred ||
 725                                                 (addrs[i].preferred == addrs[m].preferred &&
 726                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 727                                         m = i;
 728
 729                         for (size_t i = 0; i < addrlen; ++i) {
 730                                 uint32_t prefix_pref = addrs[i].preferred - now;
 731                                 uint32_t prefix_valid = addrs[i].valid - now;
 732
 733                                 if (addrs[i].prefix > 96 ||
 734                                                 addrs[i].preferred <= (uint32_t)now)
 735                                         continue;
 736
 737                                 if (a->length < 128) {
 738                                         struct dhcpv6_ia_prefix p = {
 739                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 740                                                 .len = htons(sizeof(p) - 4),
 741                                                 .preferred = htonl(prefix_pref),
 742                                                 .valid = htonl(prefix_valid),
 743                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 744                                                 .addr = addrs[i].addr
 745                                         };
 746                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 747
 748                                         size_t entrlen = sizeof(p) - 4;
 749
 750                                         if (datalen + entrlen + 4 > buflen ||
 751                                                         (a->assigned == 0 && a->managed_size == 0))
 752                                                 continue;
 753
 754                                         memcpy(buf + datalen, &p, sizeof(p));
 755                                         datalen += entrlen + 4;
 756                                 } else {
 757                                         struct dhcpv6_ia_addr n = {
 758                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 759                                                 .len = htons(sizeof(n) - 4),
 760                                                 .addr = addrs[i].addr,
 761                                                 .preferred = htonl(prefix_pref),
 762                                                 .valid = htonl(prefix_valid)
 763                                         };
 764                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 765                                         size_t entrlen = sizeof(n) - 4;
 766
 767                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m)
 768                                                 continue;
 769
 770                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 771                                                 continue;
 772
 773                                         memcpy(buf + datalen, &n, sizeof(n));
 774                                         datalen += entrlen + 4;
 775                                 }
 776
 777                                 // Calculate T1 / T2 based on non-deprecated addresses
 778                                 if (prefix_pref > 0) {
 779                                         if (prefix_pref < pref)
 780                                                 pref = prefix_pref;
 781
 782                                         if (prefix_valid < valid)
 783                                                 valid = prefix_valid;
 784                                 }
 785                         }
 786
 787                         a->valid_until = valid + now;
 788                         out.t1 = htonl(pref * 5 / 10);
 789                         out.t2 = htonl(pref * 8 / 10);
 790
 791                         if (!out.t1)
 792                                 out.t1 = htonl(1);
 793
 794                         if (!out.t2)
 795                                 out.t2 = htonl(1);
 796                 }
 797
 798                 if (!request) {
 799                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 800                         uint16_t otype, olen;
 801                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 802                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 803                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 804                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 805                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 806                                         continue;
 807
 808                                 bool found = false;
 809                                 if (a) {
 810                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 811                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 812
 813                                         for (size_t i = 0; i < addrlen; ++i) {
 814                                                 if (addrs[i].prefix > 96 ||
 815                                                                 addrs[i].preferred <= (uint32_t)now)
 816                                                         continue;
 817
 818                                                 struct in6_addr addr = addrs[i].addr;
 819                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 820                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 821
 822                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 823                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 824                                                                 found = true;
 825                                                 } else {
 826                                                         addr.s6_addr32[3] = htonl(a->assigned);
 827
 828                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 829                                                                 found = true;
 830                                                 }
 831                                         }
 832                                 }
 833
 834                                 if (!found) {
 835                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 836                                                 struct dhcpv6_ia_prefix inv = {
 837                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 838                                                         .len = htons(sizeof(inv) - 4),
 839                                                         .preferred = 0,
 840                                                         .valid = 0,
 841                                                         .prefix = p->prefix,
 842                                                         .addr = p->addr
 843                                                 };
 844
 845                                                 if (datalen + sizeof(inv) > buflen)
 846                                                         continue;
 847
 848                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 849                                                 datalen += sizeof(inv);
 850                                         } else {
 851                                                 struct dhcpv6_ia_addr inv = {
 852                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 853                                                         .len = htons(sizeof(inv) - 4),
 854                                                         .addr = n->addr,
 855                                                         .preferred = 0,
 856                                                         .valid = 0
 857                                                 };
 858
 859                                                 if (datalen + sizeof(inv) > buflen)
 860                                                         continue;
 861
 862                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 863                                                 datalen += sizeof(inv);
 864                                         }
 865                                 }
 866                         }
 867                 }
 868         }
 869
 870         out.len = htons(datalen - 4);
 871         memcpy(buf, &out, sizeof(out));
 872         return datalen;
 873 }
 874
 875
 876 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 877                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 878 {
 879         const char *type = "UNKNOWN";
 880         const char *status = "UNKNOWN";
 881
 882         if (msgtype == DHCPV6_MSG_RENEW)
 883                 return;
 884
 885         switch (msgtype) {
 886         case DHCPV6_MSG_SOLICIT:
 887                 type = "SOLICIT";
 888                 break;
 889         case DHCPV6_MSG_REQUEST:
 890                 type = "REQUEST";
 891                 break;
 892         case DHCPV6_MSG_CONFIRM:
 893                 type = "CONFIRM";
 894                 break;
 895         case DHCPV6_MSG_RENEW:
 896                 type = "RENEW";
 897                 break;
 898         case DHCPV6_MSG_REBIND:
 899                 type = "REBIND";
 900                 break;
 901         case DHCPV6_MSG_RELEASE:
 902                 type = "RELEASE";
 903                 break;
 904         case DHCPV6_MSG_DECLINE:
 905                 type = "DECLINE";
 906                 break;
 907         }
 908
 909         switch (code) {
 910         case DHCPV6_STATUS_OK:
 911                 status = "ok";
 912                 break;
 913         case DHCPV6_STATUS_NOADDRSAVAIL:
 914                 status = "no addresses available";
 915                 break;
 916         case DHCPV6_STATUS_NOBINDING:
 917                 status = "no binding";
 918                 break;
 919         case DHCPV6_STATUS_NOTONLINK:
 920                 status = "not on-link";
 921                 break;
 922         case DHCPV6_STATUS_NOPREFIXAVAIL:
 923                 status = "no prefix available";
 924                 break;
 925         }
 926
 927         char leasebuf[256] = "";
 928
 929         if (a) {
 930                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 931                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 932                 size_t lbsize = 0;
 933                 char addrbuf[INET6_ADDRSTRLEN];
 934
 935                 for (size_t i = 0; i < addrlen; ++i) {
 936                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 937                                 continue;
 938
 939                         struct in6_addr addr = addrs[i].addr;
 940                         int prefix = a->managed ? addrs[i].prefix : a->length;
 941                         if (prefix == 128)
 942                                 addr.s6_addr32[3] = htonl(a->assigned);
 943                         else
 944                                 addr.s6_addr32[1] |= htonl(a->assigned);
 945
 946                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 947                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 948                 }
 949         }
 950
 951         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 952                         duidbuf, iface->ifname, status, leasebuf);
 953 }
 954
 955
 956
 957 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 958                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 959 {
 960         time_t now = odhcpd_time();
 961         size_t response_len = 0;
 962         const struct dhcpv6_client_header *hdr = data;
 963         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 964         uint16_t otype, olen;
 965
 966         // Find and parse client-id and hostname
 967         bool accept_reconf = false;
 968         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 969         char hostname[256];
 970         size_t hostname_len = 0;
 971         bool notonlink = false;
 972         char duidbuf[261];
 973
 974         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 975                 if (otype == DHCPV6_OPT_CLIENTID) {
 976                         clid_data = odata;
 977                         clid_len = olen;
 978
 979                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 980                                 memcpy(mac, &odata[8], sizeof(mac));
 981                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 982                                 memcpy(mac, &odata[4], sizeof(mac));
 983
 984                         if (olen <= 130)
 985                                 odhcpd_hexlify(duidbuf, odata, olen);
 986                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 987                         uint8_t fqdn_buf[256];
 988                         memcpy(fqdn_buf, odata, olen);
 989                         fqdn_buf[olen++] = 0;
 990
 991                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 992                                 hostname_len = strcspn(hostname, ".");
 993                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 994                         accept_reconf = true;
 995                 }
 996         }
 997
 998         if (!clid_data || !clid_len || clid_len > 130)
 999                 goto out;
1000
1001         update(iface);
1002
1003         struct dhcpv6_assignment *first = NULL;
1004         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1005                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1006                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1007                 bool ia_addr_present = false;
1008                 if (!is_pd && !is_na)
1009                         continue;
1010
1011                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1012                 size_t ia_response_len = 0;
1013                 uint8_t reqlen = (is_pd) ? 62 : 128;
1014                 uint32_t reqhint = 0;
1015
1016                 // Parse request hint for IA-PD
1017                 if (is_pd) {
1018                         uint8_t *sdata;
1019                         uint16_t stype, slen;
1020                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1021                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1022                                         continue;
1023
1024                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1025                                 if (p->prefix) {
1026                                         reqlen = p->prefix;
1027                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1028                                         if (reqlen > 32 && reqlen <= 64)
1029                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1030                                 }
1031                         }
1032
1033                         if (reqlen > 64)
1034                                 reqlen = 64;
1035                 } else if (is_na) {
1036                         uint8_t *sdata;
1037                         uint16_t stype, slen;
1038                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1039                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1040                                         continue;
1041
1042                                 ia_addr_present = true;
1043                         }
1044                 }
1045
1046                 // Find assignment
1047                 struct dhcpv6_assignment *c, *a = NULL;
1048                 list_for_each_entry(c, &iface->ia_assignments, head) {
1049                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1050                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1051                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1052                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1053                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1054                                 a = c;
1055
1056                                 // Reset state
1057                                 apply_lease(iface, a, false);
1058                                 memcpy(a->clid_data, clid_data, clid_len);
1059                                 a->clid_len = clid_len;
1060                                 a->iaid = ia->iaid;
1061                                 a->peer = *addr;
1062                                 a->reconf_cnt = 0;
1063                                 a->reconf_sent = 0;
1064                                 break;
1065                         }
1066                 }
1067
1068                 // Generic message handling
1069                 uint16_t status = DHCPV6_STATUS_OK;
1070                 if (a && a->managed_size < 0) {
1071                         return -1;
1072                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1073                         bool assigned = !!a;
1074
1075                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1076                                 a = calloc(1, sizeof(*a) + clid_len);
1077                                 if (a) {
1078                                         a->clid_len = clid_len;
1079                                         a->iaid = ia->iaid;
1080                                         a->length = reqlen;
1081                                         a->peer = *addr;
1082                                         a->assigned = reqhint;
1083
1084                                         if (first)
1085                                                 memcpy(a->key, first->key, sizeof(a->key));
1086                                         else
1087                                                 odhcpd_urandom(a->key, sizeof(a->key));
1088                                         memcpy(a->clid_data, clid_data, clid_len);
1089
1090                                         if (is_pd)
1091                                                 while (!(assigned = assign_pd(iface, a)) &&
1092                                                                 !a->managed_size && ++a->length <= 64);
1093                                         else
1094                                                 assigned = assign_na(iface, a);
1095
1096                                         if (a->managed_size && !assigned)
1097                                                 return -1;
1098                                 }
1099                         }
1100
1101                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1102                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1103                         } else if (assigned && !first) { //
1104                                 size_t handshake_len = 4;
1105                                 buf[0] = 0;
1106                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1107                                 buf[2] = 0;
1108                                 buf[3] = 0;
1109
1110                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1111                                         struct dhcpv6_auth_reconfigure auth = {
1112                                                 htons(DHCPV6_OPT_AUTH),
1113                                                 htons(sizeof(auth) - 4),
1114                                                 3, 1, 0,
1115                                                 {htonl(time(NULL)), htonl(++serial)},
1116                                                 1,
1117                                                 {0}
1118                                         };
1119                                         memcpy(auth.key, a->key, sizeof(a->key));
1120                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1121                                         handshake_len += sizeof(auth);
1122                                 }
1123
1124                                 buf += handshake_len;
1125                                 buflen -= handshake_len;
1126                                 response_len += handshake_len;
1127
1128                                 first = a;
1129                         }
1130
1131                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1132
1133                         // Was only a solicitation: mark binding for removal
1134                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1135                                 a->valid_until = 0;
1136                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1137                                 if (hostname_len > 0) {
1138                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1139                                         if (a->hostname) {
1140                                                 memcpy(a->hostname, hostname, hostname_len);
1141                                                 a->hostname[hostname_len] = 0;
1142                                         }
1143                                 }
1144                                 a->accept_reconf = accept_reconf;
1145                                 apply_lease(iface, a, true);
1146                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1147                                 free_dhcpv6_assignment(a);
1148                         }
1149                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1150                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1151                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1152                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1153                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1154                                 status = DHCPV6_STATUS_NOBINDING;
1155                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1156                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1157                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1158                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1159                                 if (a)
1160                                         apply_lease(iface, a, true);
1161                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1162                                 a->valid_until = 0;
1163                                 apply_lease(iface, a, false);
1164                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1165                                 a->clid_len = 0;
1166                                 a->valid_until = now + 3600; // Block address for 1h
1167                         }
1168                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1169                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1170                         status = DHCPV6_STATUS_NOTONLINK;
1171                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1172                         notonlink = true;
1173                 }
1174
1175                 buf += ia_response_len;
1176                 buflen -= ia_response_len;
1177                 response_len += ia_response_len;
1178                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1179         }
1180
1181         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1182                         response_len + 6 < buflen) {
1183                 buf[0] = 0;
1184                 buf[1] = DHCPV6_OPT_STATUS;
1185                 buf[2] = 0;
1186                 buf[3] = 2;
1187                 buf[4] = 0;
1188                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1189                 response_len += 6;
1190         }
1191
1192         dhcpv6_write_statefile();
1193
1194 out:
1195         return response_len;
1196 }