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);
  64 }
  65
  66
  67 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  68 {
  69         if (!enable && iface->ia_assignments.next) {
  70                 struct dhcpv6_assignment *c;
  71                 while (!list_empty(&iface->ia_assignments)) {
  72                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  73                         free_dhcpv6_assignment(c);
  74                 }
  75         }
  76
  77         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  78                 if (!iface->ia_assignments.next)
  79                         INIT_LIST_HEAD(&iface->ia_assignments);
  80
  81                 if (list_empty(&iface->ia_assignments)) {
  82                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  83                         if (!border) {
  84                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  85                                 return -1;
  86                         }
  87
  88                         border->length = 64;
  89                         list_add(&border->head, &iface->ia_assignments);
  90                 }
  91
  92                 update(iface);
  93
  94                 // Parse static entries
  95                 struct lease *lease;
  96                 list_for_each_entry(lease, &leases, head) {
  97                         // Construct entry
  98                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  99                         if (!a) {
 100                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
 101                                         iface->ifname);
 102                                 return -1;
 103                         }
 104
 105                         a->clid_len = lease->duid_len;
 106                         a->length = 128;
 107                         if (lease->hostid) {
 108                                 a->assigned = lease->hostid;
 109                         } else {
 110                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 111                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 112                         }
 113                         odhcpd_urandom(a->key, sizeof(a->key));
 114                         memcpy(a->clid_data, lease->duid, a->clid_len);
 115                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 116
 117                         // Assign to all interfaces
 118                         struct dhcpv6_assignment *c;
 119                         list_for_each_entry(c, &iface->ia_assignments, head) {
 120                                 if (c->length != 128 || c->assigned > a->assigned) {
 121                                         list_add_tail(&a->head, &c->head);
 122                                         break;
 123                                 } else if (c->assigned == a->assigned) {
 124                                         // Already an assignment with that number
 125                                         break;
 126                                 }
 127                         }
 128
 129                         if (a->head.next) {
 130                                 if (lease->hostname[0]) {
 131                                         free(a->hostname);
 132                                         a->hostname = strdup(lease->hostname);
 133                                 }
 134                         } else {
 135                                 free(a->hostname);
 136                                 free(a);
 137                         }
 138                 }
 139         }
 140         return 0;
 141 }
 142
 143
 144 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 145 {
 146         struct {
 147                 struct dhcpv6_client_header hdr;
 148                 uint16_t srvid_type;
 149                 uint16_t srvid_len;
 150                 uint16_t duid_type;
 151                 uint16_t hardware_type;
 152                 uint8_t mac[6];
 153                 uint16_t msg_type;
 154                 uint16_t msg_len;
 155                 uint8_t msg_id;
 156                 struct dhcpv6_auth_reconfigure auth;
 157                 uint16_t clid_type;
 158                 uint16_t clid_len;
 159                 uint8_t clid_data[128];
 160         } __attribute__((packed)) reconf_msg = {
 161                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 162                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 163                 .srvid_len = htons(10),
 164                 .duid_type = htons(3),
 165                 .hardware_type = htons(1),
 166                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 167                 .msg_len = htons(1),
 168                 .msg_id = DHCPV6_MSG_RENEW,
 169                 .auth = {htons(DHCPV6_OPT_AUTH),
 170                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 171                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 172                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 173                 .clid_len = htons(assign->clid_len),
 174                 .clid_data = {0},
 175         };
 176
 177         odhcpd_get_mac(iface, reconf_msg.mac);
 178         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 179         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 180
 181         md5_ctx_t md5;
 182         uint8_t secretbytes[64];
 183         memset(secretbytes, 0, sizeof(secretbytes));
 184         memcpy(secretbytes, assign->key, sizeof(assign->key));
 185
 186         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 187                 secretbytes[i] ^= 0x36;
 188
 189         md5_begin(&md5);
 190         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 191         md5_hash(iov.iov_base, iov.iov_len, &md5);
 192         md5_end(reconf_msg.auth.key, &md5);
 193
 194         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 195                 secretbytes[i] ^= 0x36;
 196                 secretbytes[i] ^= 0x5c;
 197         }
 198
 199         md5_begin(&md5);
 200         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 201         md5_hash(reconf_msg.auth.key, 16, &md5);
 202         md5_end(reconf_msg.auth.key, &md5);
 203
 204         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 205 }
 206
 207
 208 void dhcpv6_write_statefile(void)
 209 {
 210         md5_ctx_t md5;
 211         md5_begin(&md5);
 212
 213         if (config.dhcp_statefile) {
 214                 time_t now = odhcpd_time(), wall_time = time(NULL);
 215                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 216                 if (fd < 0)
 217                         return;
 218
 219                 lockf(fd, F_LOCK, 0);
 220                 if (ftruncate(fd, 0) < 0) {}
 221
 222                 FILE *fp = fdopen(fd, "w");
 223                 if (!fp) {
 224                         close(fd);
 225                         return;
 226                 }
 227
 228                 struct interface *iface;
 229                 list_for_each_entry(iface, &interfaces, head) {
 230                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 231                                 continue;
 232
 233                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 234                                 struct dhcpv6_assignment *c;
 235                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 236                                         if (c->clid_len == 0 || c->managed_size < 0)
 237                                                 continue;
 238
 239                                         char ipbuf[INET6_ADDRSTRLEN];
 240                                         char leasebuf[512];
 241                                         char duidbuf[264];
 242                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 243
 244                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 245                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 246                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 247                                                         (c->hostname ? c->hostname : "-"),
 248                                                         (unsigned)(c->valid_until > now ?
 249                                                                         (c->valid_until - now + wall_time) : 0),
 250                                                         c->assigned, (unsigned)c->length);
 251
 252                                         struct in6_addr addr;
 253                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 254                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 255                                         size_t m = 0;
 256
 257                                         for (size_t i = 0; i < addrlen; ++i)
 258                                                 if (addrs[i].preferred > addrs[m].preferred ||
 259                                                                 (addrs[i].preferred == addrs[m].preferred &&
 260                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 261                                                         m = i;
 262
 263                                         for (size_t i = 0; i < addrlen; ++i) {
 264                                                 if (addrs[i].prefix > 96 || c->valid_until <= now ||
 265                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 266                                                                                 addrs[i].prefix == 64))
 267                                                         continue;
 268
 269                                                 addr = addrs[i].addr;
 270                                                 if (c->length == 128)
 271                                                         addr.s6_addr32[3] = htonl(c->assigned);
 272                                                 else
 273                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 274
 275                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 276
 277                                                 if (c->length == 128 && c->hostname) {
 278                                                         fputs(ipbuf, fp);
 279
 280                                                         char b[256];
 281                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 282                                                                         iface->search, b, sizeof(b)) > 0)
 283                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 284
 285                                                         fprintf(fp, "\t%s\n", c->hostname);
 286                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 287                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 288                                                 }
 289
 290                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 291                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 292                                         }
 293                                         leasebuf[l - 1] = '\n';
 294                                         fwrite(leasebuf, 1, l, fp);
 295                                 }
 296                         }
 297
 298                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 299                                 struct dhcpv4_assignment *c;
 300                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 301                                         char ipbuf[INET6_ADDRSTRLEN];
 302                                         char leasebuf[512];
 303                                         char duidbuf[16];
 304                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 305
 306                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 307                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 308                                                         iface->ifname, duidbuf,
 309                                                         (c->hostname ? c->hostname : "-"),
 310                                                         (unsigned)(c->valid_until > now ?
 311                                                                         (c->valid_until - now + wall_time) : 0),
 312                                                         c->addr);
 313
 314                                         struct in_addr addr = {htonl(c->addr)};
 315                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 316
 317                                         if (c->hostname[0]) {
 318                                                 fputs(ipbuf, fp);
 319
 320                                                 char b[256];
 321                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 322                                                                 iface->search, b, sizeof(b)) > 0)
 323                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 324
 325                                                 fprintf(fp, "\t%s\n", c->hostname);
 326                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 327                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 328                                         }
 329
 330                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 331                                         leasebuf[l - 1] = '\n';
 332                                         fwrite(leasebuf, 1, l, fp);
 333                                 }
 334                         }
 335                 }
 336
 337                 fclose(fp);
 338         }
 339
 340         uint8_t newmd5[16];
 341         md5_end(newmd5, &md5);
 342
 343         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 344                 memcpy(statemd5, newmd5, sizeof(statemd5));
 345                 char *argv[2] = {config.dhcp_cb, NULL};
 346                 if (!vfork()) {
 347                         execv(argv[0], argv);
 348                         _exit(128);
 349                 }
 350         }
 351 }
 352
 353
 354 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 355 {
 356         if (a->length > 64 || a->managed_size < 0)
 357                 return;
 358
 359         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 360         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 361
 362         for (size_t i = 0; i < addrlen; ++i) {
 363                 struct in6_addr prefix = addrs[i].addr;
 364                 prefix.s6_addr32[1] |= htonl(a->assigned);
 365                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 366                                 iface, &a->peer.sin6_addr, add);
 367         }
 368 }
 369
 370
 371 // More data was received from TCP connection
 372 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 373 {
 374         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 375         time_t now = odhcpd_time();
 376         bool first = c->managed_size < 0;
 377
 378         for (;;) {
 379                 int pending;
 380                 char *data = ustream_get_read_buf(s, &pending);
 381                 char *end = memmem(data, pending, "\n\n", 2);
 382
 383                 if (!end)
 384                         break;
 385
 386                 end += 2;
 387                 end[-1] = 0;
 388
 389                 c->managed_size = 0;
 390                 if (c->accept_reconf)
 391                         c->reconf_cnt = 1;
 392
 393                 char *saveptr;
 394                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 395                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 396                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 397
 398                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 399                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 400                                 continue;
 401
 402                         x = strtok_r(NULL, ",", &saveptr2);
 403                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 404                                 continue;
 405
 406                         x = strtok_r(NULL, ",", &saveptr2);
 407                         if (sscanf(x, "%u", &n->preferred) < 1)
 408                                 continue;
 409
 410                         x = strtok_r(NULL, ",", &saveptr2);
 411                         if (sscanf(x, "%u", &n->valid) < 1)
 412                                 continue;
 413
 414                         if (n->preferred > n->valid)
 415                                 continue;
 416
 417                         if (UINT32_MAX - now < n->preferred)
 418                                 n->preferred = UINT32_MAX;
 419                         else
 420                                 n->preferred += now;
 421
 422                         if (UINT32_MAX - now < n->valid)
 423                                 n->valid = UINT32_MAX;
 424                         else
 425                                 n->valid += now;
 426
 427                         n->dprefix = 0;
 428
 429                         ++c->managed_size;
 430                 }
 431
 432                 ustream_consume(s, end - data);
 433         }
 434
 435         if (first && c->managed_size == 0)
 436                 free_dhcpv6_assignment(c);
 437         else if (first)
 438                 c->valid_until = now + 150;
 439 }
 440
 441
 442 // TCP transmission has ended, either because of success or timeout or other error
 443 static void managed_handle_pd_done(struct ustream *s)
 444 {
 445         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 446         c->valid_until = odhcpd_time() + 15;
 447         c->managed_size = 0;
 448         if (c->accept_reconf)
 449                 c->reconf_cnt = 1;
 450 }
 451
 452
 453
 454 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 455 {
 456         struct dhcpv6_assignment *c;
 457
 458         if (iface->dhcpv6_pd_manager[0]) {
 459                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 460                 if (fd >= 0) {
 461                         char iaidbuf[298];
 462                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 463
 464                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 465                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 466                         ustream_fd_init(&assign->managed_sock, fd);
 467                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 468                                         iaidbuf, assign->iaid, assign->length);
 469                         ustream_write_pending(&assign->managed_sock.stream);
 470                         assign->managed_size = -1;
 471                         assign->valid_until = odhcpd_time() + 15;
 472                         list_add(&assign->head, &iface->ia_assignments);
 473
 474                         // Wait initial period of up to 250ms for immediate assignment
 475                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 476                         poll(&pfd, 1, 250);
 477                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 478
 479                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 480                                 return true;
 481                 }
 482
 483                 return false;
 484         } else if (iface->ia_addr_len < 1) {
 485                 return false;
 486         }
 487
 488         // Try honoring the hint first
 489         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 490         if (assign->assigned) {
 491                 list_for_each_entry(c, &iface->ia_assignments, head) {
 492                         if (c->length == 128 || c->length == 0)
 493                                 continue;
 494
 495                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 496                                 list_add_tail(&assign->head, &c->head);
 497                                 apply_lease(iface, assign, true);
 498                                 return true;
 499                         }
 500
 501                         if (c->assigned != 0)
 502                                 current = (c->assigned + (1 << (64 - c->length)));
 503                 }
 504         }
 505
 506         // Fallback to a variable assignment
 507         current = 1;
 508         list_for_each_entry(c, &iface->ia_assignments, head) {
 509                 if (c->length == 128 || c->length == 0)
 510                         continue;
 511
 512                 current = (current + asize) & (~asize);
 513                 if (current + asize < c->assigned) {
 514                         assign->assigned = current;
 515                         list_add_tail(&assign->head, &c->head);
 516                         apply_lease(iface, assign, true);
 517                         return true;
 518                 }
 519
 520                 if (c->assigned != 0)
 521                         current = (c->assigned + (1 << (64 - c->length)));
 522         }
 523
 524         return false;
 525 }
 526
 527
 528 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 529 {
 530         // Seed RNG with checksum of DUID
 531         uint32_t seed = 0;
 532         for (size_t i = 0; i < assign->clid_len; ++i)
 533                 seed += assign->clid_data[i];
 534         srand(seed);
 535
 536         // Try to assign up to 100x
 537         for (size_t i = 0; i < 100; ++i) {
 538                 uint32_t try;
 539                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 540
 541                 struct dhcpv6_assignment *c;
 542                 list_for_each_entry(c, &iface->ia_assignments, head) {
 543                         if (c->length == 0)
 544                                 continue;
 545
 546                         if (c->assigned > try || c->length != 128) {
 547                                 assign->assigned = try;
 548                                 list_add_tail(&assign->head, &c->head);
 549                                 return true;
 550                         } else if (c->assigned == try) {
 551                                 break;
 552                         }
 553                 }
 554         }
 555
 556         return false;
 557 }
 558
 559
 560 static int prefixcmp(const void *va, const void *vb)
 561 {
 562         const struct odhcpd_ipaddr *a = va, *b = vb;
 563         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 564         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 565         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 566 }
 567
 568
 569 static void update(struct interface *iface)
 570 {
 571         struct odhcpd_ipaddr addr[8];
 572         memset(addr, 0, sizeof(addr));
 573         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 574
 575         if (len < 0)
 576                 return;
 577
 578         qsort(addr, len, sizeof(*addr), prefixcmp);
 579
 580         time_t now = odhcpd_time();
 581         int minprefix = -1;
 582
 583         for (int i = 0; i < len; ++i) {
 584                 if (addr[i].preferred > 0 && addr[i].prefix > minprefix)
 585                         minprefix = addr[i].prefix;
 586
 587                 addr[i].addr.s6_addr32[3] = 0;
 588
 589                 if (addr[i].preferred < UINT32_MAX - now)
 590                         addr[i].preferred += now;
 591
 592                 if (addr[i].valid < UINT32_MAX - now)
 593                         addr[i].valid += now;
 594         }
 595
 596         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 597         if (minprefix > 32 && minprefix <= 64)
 598                 border->assigned = 1U << (64 - minprefix);
 599         else
 600                 border->assigned = 0;
 601
 602         bool change = len != (int)iface->ia_addr_len;
 603         for (int i = 0; !change && i < len; ++i)
 604                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 605                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 606                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 607                                 (addr[i].valid > (uint32_t)now + 7200) !=
 608                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 609                         change = true;
 610
 611         if (change) {
 612                 struct dhcpv6_assignment *c;
 613                 list_for_each_entry(c, &iface->ia_assignments, head)
 614                         if (c != border && !iface->managed)
 615                                 apply_lease(iface, c, false);
 616         }
 617
 618         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 619         iface->ia_addr_len = len;
 620
 621         if (change) { // Addresses / prefixes have changed
 622                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 623                 struct dhcpv6_assignment *c, *d;
 624                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 625                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 626                                 continue;
 627
 628                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 629                                 list_move(&c->head, &reassign);
 630                         else if (c != border)
 631                                 apply_lease(iface, c, true);
 632
 633                         if (c->accept_reconf && c->reconf_cnt == 0) {
 634                                 c->reconf_cnt = 1;
 635                                 c->reconf_sent = now;
 636                                 send_reconf(iface, c);
 637
 638                                 // Leave all other assignments of that client alone
 639                                 struct dhcpv6_assignment *a;
 640                                 list_for_each_entry(a, &iface->ia_assignments, head)
 641                                         if (a != c && a->clid_len == c->clid_len &&
 642                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 643                                                 c->reconf_cnt = INT_MAX;
 644                         }
 645                 }
 646
 647                 while (!list_empty(&reassign)) {
 648                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 649                         list_del(&c->head);
 650                         if (!assign_pd(iface, c)) {
 651                                 c->assigned = 0;
 652                                 list_add(&c->head, &iface->ia_assignments);
 653                         }
 654                 }
 655
 656                 dhcpv6_write_statefile();
 657         }
 658 }
 659
 660
 661 static void reconf_timer(struct uloop_timeout *event)
 662 {
 663         time_t now = odhcpd_time();
 664         struct interface *iface;
 665         list_for_each_entry(iface, &interfaces, head) {
 666                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 667                         continue;
 668
 669                 struct dhcpv6_assignment *a, *n;
 670                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 671                         if (a->valid_until < now) {
 672                                 if ((a->length < 128 && a->clid_len > 0) ||
 673                                                 (a->length == 128 && a->clid_len == 0)) {
 674                                         list_del(&a->head);
 675                                         free_dhcpv6_assignment(a);
 676                                 }
 677                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 678                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 679                                 ++a->reconf_cnt;
 680                                 a->reconf_sent = now;
 681                                 send_reconf(iface, a);
 682                         }
 683                 }
 684         }
 685         uloop_timeout_set(event, 2000);
 686 }
 687
 688
 689 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 690                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 691                 struct interface *iface, bool request)
 692 {
 693         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 694                 return 0;
 695
 696         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 697         size_t datalen = sizeof(out);
 698         time_t now = odhcpd_time();
 699
 700         if (status) {
 701                 struct __attribute__((packed)) {
 702                         uint16_t type;
 703                         uint16_t len;
 704                         uint16_t value;
 705                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 706                                 htons(status)};
 707
 708                 memcpy(buf + datalen, &stat, sizeof(stat));
 709                 datalen += sizeof(stat);
 710         } else {
 711                 if (a) {
 712                         uint32_t leasetime = iface->dhcpv4_leasetime;
 713                         if (leasetime == 0)
 714                                 leasetime = 3600;
 715                         else if (leasetime < 60)
 716                                 leasetime = 60;
 717
 718                         uint32_t pref = leasetime;
 719                         uint32_t valid = leasetime;
 720
 721                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 722                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 723                         size_t m = 0;
 724
 725                         for (size_t i = 0; i < addrlen; ++i)
 726                                 if (addrs[i].preferred > addrs[m].preferred ||
 727                                                 (addrs[i].preferred == addrs[m].preferred &&
 728                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 729                                         m = i;
 730
 731                         for (size_t i = 0; i < addrlen; ++i) {
 732                                 uint32_t prefix_pref = addrs[i].preferred;
 733                                 uint32_t prefix_valid = addrs[i].valid;
 734
 735                                 if (addrs[i].prefix > 96 ||
 736                                                 addrs[i].preferred <= (uint32_t)now)
 737                                         continue;
 738
 739                                 if (prefix_pref != UINT32_MAX)
 740                                         prefix_pref -= now;
 741
 742                                 if (prefix_valid != UINT32_MAX)
 743                                         prefix_valid -= now;
 744
 745                                 if (a->length < 128) {
 746                                         struct dhcpv6_ia_prefix p = {
 747                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 748                                                 .len = htons(sizeof(p) - 4),
 749                                                 .preferred = htonl(prefix_pref),
 750                                                 .valid = htonl(prefix_valid),
 751                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 752                                                 .addr = addrs[i].addr
 753                                         };
 754                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 755
 756                                         size_t entrlen = sizeof(p) - 4;
 757
 758                                         if (datalen + entrlen + 4 > buflen ||
 759                                                         (a->assigned == 0 && a->managed_size == 0))
 760                                                 continue;
 761
 762                                         memcpy(buf + datalen, &p, sizeof(p));
 763                                         datalen += entrlen + 4;
 764                                 } else {
 765                                         struct dhcpv6_ia_addr n = {
 766                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 767                                                 .len = htons(sizeof(n) - 4),
 768                                                 .addr = addrs[i].addr,
 769                                                 .preferred = htonl(prefix_pref),
 770                                                 .valid = htonl(prefix_valid)
 771                                         };
 772                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 773                                         size_t entrlen = sizeof(n) - 4;
 774
 775                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 776                                                         addrs[i].prefix == 64)
 777                                                 continue;
 778
 779                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 780                                                 continue;
 781
 782                                         memcpy(buf + datalen, &n, sizeof(n));
 783                                         datalen += entrlen + 4;
 784                                 }
 785
 786                                 // Calculate T1 / T2 based on non-deprecated addresses
 787                                 if (prefix_pref > 0) {
 788                                         if (prefix_pref < pref)
 789                                                 pref = prefix_pref;
 790
 791                                         if (prefix_valid < valid)
 792                                                 valid = prefix_valid;
 793                                 }
 794                         }
 795
 796                         a->valid_until = valid + now;
 797                         out.t1 = htonl(pref * 5 / 10);
 798                         out.t2 = htonl(pref * 8 / 10);
 799
 800                         if (!out.t1)
 801                                 out.t1 = htonl(1);
 802
 803                         if (!out.t2)
 804                                 out.t2 = htonl(1);
 805                 }
 806
 807                 if (!request) {
 808                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 809                         uint16_t otype, olen;
 810                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 811                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 812                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 813                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 814                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 815                                         continue;
 816
 817                                 bool found = false;
 818                                 if (a) {
 819                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 820                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 821
 822                                         for (size_t i = 0; i < addrlen; ++i) {
 823                                                 if (addrs[i].prefix > 96 ||
 824                                                                 addrs[i].preferred <= (uint32_t)now)
 825                                                         continue;
 826
 827                                                 struct in6_addr addr = addrs[i].addr;
 828                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 829                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 830
 831                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 832                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 833                                                                 found = true;
 834                                                 } else {
 835                                                         addr.s6_addr32[3] = htonl(a->assigned);
 836
 837                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 838                                                                 found = true;
 839                                                 }
 840                                         }
 841                                 }
 842
 843                                 if (!found) {
 844                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 845                                                 struct dhcpv6_ia_prefix inv = {
 846                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 847                                                         .len = htons(sizeof(inv) - 4),
 848                                                         .preferred = 0,
 849                                                         .valid = 0,
 850                                                         .prefix = p->prefix,
 851                                                         .addr = p->addr
 852                                                 };
 853
 854                                                 if (datalen + sizeof(inv) > buflen)
 855                                                         continue;
 856
 857                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 858                                                 datalen += sizeof(inv);
 859                                         } else {
 860                                                 struct dhcpv6_ia_addr inv = {
 861                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 862                                                         .len = htons(sizeof(inv) - 4),
 863                                                         .addr = n->addr,
 864                                                         .preferred = 0,
 865                                                         .valid = 0
 866                                                 };
 867
 868                                                 if (datalen + sizeof(inv) > buflen)
 869                                                         continue;
 870
 871                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 872                                                 datalen += sizeof(inv);
 873                                         }
 874                                 }
 875                         }
 876                 }
 877         }
 878
 879         out.len = htons(datalen - 4);
 880         memcpy(buf, &out, sizeof(out));
 881         return datalen;
 882 }
 883
 884
 885 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 886                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 887 {
 888         const char *type = "UNKNOWN";
 889         const char *status = "UNKNOWN";
 890
 891         if (msgtype == DHCPV6_MSG_RENEW)
 892                 return;
 893
 894         switch (msgtype) {
 895         case DHCPV6_MSG_SOLICIT:
 896                 type = "SOLICIT";
 897                 break;
 898         case DHCPV6_MSG_REQUEST:
 899                 type = "REQUEST";
 900                 break;
 901         case DHCPV6_MSG_CONFIRM:
 902                 type = "CONFIRM";
 903                 break;
 904         case DHCPV6_MSG_RENEW:
 905                 type = "RENEW";
 906                 break;
 907         case DHCPV6_MSG_REBIND:
 908                 type = "REBIND";
 909                 break;
 910         case DHCPV6_MSG_RELEASE:
 911                 type = "RELEASE";
 912                 break;
 913         case DHCPV6_MSG_DECLINE:
 914                 type = "DECLINE";
 915                 break;
 916         }
 917
 918         switch (code) {
 919         case DHCPV6_STATUS_OK:
 920                 status = "ok";
 921                 break;
 922         case DHCPV6_STATUS_NOADDRSAVAIL:
 923                 status = "no addresses available";
 924                 break;
 925         case DHCPV6_STATUS_NOBINDING:
 926                 status = "no binding";
 927                 break;
 928         case DHCPV6_STATUS_NOTONLINK:
 929                 status = "not on-link";
 930                 break;
 931         case DHCPV6_STATUS_NOPREFIXAVAIL:
 932                 status = "no prefix available";
 933                 break;
 934         }
 935
 936         char leasebuf[256] = "";
 937
 938         if (a) {
 939                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 940                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 941                 size_t lbsize = 0;
 942                 char addrbuf[INET6_ADDRSTRLEN];
 943
 944                 for (size_t i = 0; i < addrlen; ++i) {
 945                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 946                                 continue;
 947
 948                         struct in6_addr addr = addrs[i].addr;
 949                         int prefix = a->managed ? addrs[i].prefix : a->length;
 950                         if (prefix == 128)
 951                                 addr.s6_addr32[3] = htonl(a->assigned);
 952                         else
 953                                 addr.s6_addr32[1] |= htonl(a->assigned);
 954
 955                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 956                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 957                 }
 958         }
 959
 960         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 961                         duidbuf, iface->ifname, status, leasebuf);
 962 }
 963
 964
 965
 966 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 967                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 968 {
 969         time_t now = odhcpd_time();
 970         size_t response_len = 0;
 971         const struct dhcpv6_client_header *hdr = data;
 972         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 973         uint16_t otype, olen;
 974
 975         // Find and parse client-id and hostname
 976         bool accept_reconf = false;
 977         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 978         char hostname[256];
 979         size_t hostname_len = 0;
 980         bool notonlink = false;
 981         char duidbuf[261];
 982
 983         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 984                 if (otype == DHCPV6_OPT_CLIENTID) {
 985                         clid_data = odata;
 986                         clid_len = olen;
 987
 988                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 989                                 memcpy(mac, &odata[8], sizeof(mac));
 990                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 991                                 memcpy(mac, &odata[4], sizeof(mac));
 992
 993                         if (olen <= 130)
 994                                 odhcpd_hexlify(duidbuf, odata, olen);
 995                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 996                         uint8_t fqdn_buf[256];
 997                         memcpy(fqdn_buf, odata, olen);
 998                         fqdn_buf[olen++] = 0;
 999
1000                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
1001                                 hostname_len = strcspn(hostname, ".");
1002                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
1003                         accept_reconf = true;
1004                 }
1005         }
1006
1007         if (!clid_data || !clid_len || clid_len > 130)
1008                 goto out;
1009
1010         update(iface);
1011
1012         struct dhcpv6_assignment *first = NULL;
1013         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1014                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1015                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1016                 bool ia_addr_present = false;
1017                 if (!is_pd && !is_na)
1018                         continue;
1019
1020                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1021                 size_t ia_response_len = 0;
1022                 uint8_t reqlen = (is_pd) ? 62 : 128;
1023                 uint32_t reqhint = 0;
1024
1025                 // Parse request hint for IA-PD
1026                 if (is_pd) {
1027                         uint8_t *sdata;
1028                         uint16_t stype, slen;
1029                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1030                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1031                                         continue;
1032
1033                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1034                                 if (p->prefix) {
1035                                         reqlen = p->prefix;
1036                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1037                                         if (reqlen > 32 && reqlen <= 64)
1038                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1039                                 }
1040                         }
1041
1042                         if (reqlen > 64)
1043                                 reqlen = 64;
1044                 } else if (is_na) {
1045                         uint8_t *sdata;
1046                         uint16_t stype, slen;
1047                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1048                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1049                                         continue;
1050
1051                                 ia_addr_present = true;
1052                         }
1053                 }
1054
1055                 // Find assignment
1056                 struct dhcpv6_assignment *c, *a = NULL;
1057                 list_for_each_entry(c, &iface->ia_assignments, head) {
1058                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1059                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1060                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1061                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1062                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1063                                 a = c;
1064
1065                                 // Reset state
1066                                 apply_lease(iface, a, false);
1067                                 memcpy(a->clid_data, clid_data, clid_len);
1068                                 a->clid_len = clid_len;
1069                                 a->iaid = ia->iaid;
1070                                 a->peer = *addr;
1071                                 a->reconf_cnt = 0;
1072                                 a->reconf_sent = 0;
1073                                 break;
1074                         }
1075                 }
1076
1077                 // Generic message handling
1078                 uint16_t status = DHCPV6_STATUS_OK;
1079                 if (a && a->managed_size < 0) {
1080                         return -1;
1081                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1082                         bool assigned = !!a;
1083
1084                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1085                                 a = calloc(1, sizeof(*a) + clid_len);
1086                                 if (a) {
1087                                         a->clid_len = clid_len;
1088                                         a->iaid = ia->iaid;
1089                                         a->length = reqlen;
1090                                         a->peer = *addr;
1091                                         a->assigned = reqhint;
1092
1093                                         if (first)
1094                                                 memcpy(a->key, first->key, sizeof(a->key));
1095                                         else
1096                                                 odhcpd_urandom(a->key, sizeof(a->key));
1097                                         memcpy(a->clid_data, clid_data, clid_len);
1098
1099                                         if (is_pd)
1100                                                 while (!(assigned = assign_pd(iface, a)) &&
1101                                                                 !a->managed_size && ++a->length <= 64);
1102                                         else
1103                                                 assigned = assign_na(iface, a);
1104
1105                                         if (a->managed_size && !assigned)
1106                                                 return -1;
1107                                 }
1108                         }
1109
1110                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1111                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1112                         } else if (assigned && !first) { //
1113                                 size_t handshake_len = 4;
1114                                 buf[0] = 0;
1115                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1116                                 buf[2] = 0;
1117                                 buf[3] = 0;
1118
1119                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1120                                         struct dhcpv6_auth_reconfigure auth = {
1121                                                 htons(DHCPV6_OPT_AUTH),
1122                                                 htons(sizeof(auth) - 4),
1123                                                 3, 1, 0,
1124                                                 {htonl(time(NULL)), htonl(++serial)},
1125                                                 1,
1126                                                 {0}
1127                                         };
1128                                         memcpy(auth.key, a->key, sizeof(a->key));
1129                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1130                                         handshake_len += sizeof(auth);
1131                                 }
1132
1133                                 buf += handshake_len;
1134                                 buflen -= handshake_len;
1135                                 response_len += handshake_len;
1136
1137                                 first = a;
1138                         }
1139
1140                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1141
1142                         // Was only a solicitation: mark binding for removal
1143                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1144                                 a->valid_until = 0;
1145                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1146                                 if (hostname_len > 0) {
1147                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1148                                         if (a->hostname) {
1149                                                 memcpy(a->hostname, hostname, hostname_len);
1150                                                 a->hostname[hostname_len] = 0;
1151                                         }
1152                                 }
1153                                 a->accept_reconf = accept_reconf;
1154                                 apply_lease(iface, a, true);
1155                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1156                                 free_dhcpv6_assignment(a);
1157                         }
1158                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1159                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1160                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1161                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1162                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1163                                 status = DHCPV6_STATUS_NOBINDING;
1164                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1165                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1166                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1167                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1168                                 if (a)
1169                                         apply_lease(iface, a, true);
1170                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1171                                 a->valid_until = 0;
1172                                 apply_lease(iface, a, false);
1173                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1174                                 a->clid_len = 0;
1175                                 a->valid_until = now + 3600; // Block address for 1h
1176                         }
1177                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1178                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1179                         status = DHCPV6_STATUS_NOTONLINK;
1180                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1181                         notonlink = true;
1182                 }
1183
1184                 buf += ia_response_len;
1185                 buflen -= ia_response_len;
1186                 response_len += ia_response_len;
1187                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1188         }
1189
1190         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1191                         response_len + 6 < buflen) {
1192                 buf[0] = 0;
1193                 buf[1] = DHCPV6_OPT_STATUS;
1194                 buf[2] = 0;
1195                 buf[3] = 2;
1196                 buf[4] = 0;
1197                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1198                 response_len += 6;
1199         }
1200
1201         dhcpv6_write_statefile();
1202
1203 out:
1204         return response_len;
1205 }