src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include "odhcpd.h"
  17 #include "dhcpv6.h"
  18 #include "dhcpv4.h"
  19 #include "libubox/md5.h"
  20 #include "libubox/usock.h"
  21
  22 #include <time.h>
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <stdio.h>
  26 #include <poll.h>
  27 #include <alloca.h>
  28 #include <resolv.h>
  29 #include <limits.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <stdbool.h>
  34 #include <arpa/inet.h>
  35 #include <sys/timerfd.h>
  36
  37 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
  38 static void reconf_timer(struct uloop_timeout *event);
  39 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  40 static uint32_t serial = 0;
  41 static uint8_t statemd5[16];
  42
  43 int dhcpv6_ia_init(void)
  44 {
  45         uloop_timeout_set(&reconf_event, 2000);
  46         return 0;
  47 }
  48
  49 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  50 {
  51         if (!enable && iface->ia_assignments.next) {
  52                 struct dhcpv6_assignment *c;
  53                 while (!list_empty(&iface->ia_assignments)) {
  54                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  55                         free_dhcpv6_assignment(c);
  56                 }
  57         }
  58
  59         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  60                 if (!iface->ia_assignments.next)
  61                         INIT_LIST_HEAD(&iface->ia_assignments);
  62
  63                 if (list_empty(&iface->ia_assignments)) {
  64                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  65                         if (!border) {
  66                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  67                                 return -1;
  68                         }
  69
  70                         border->length = 64;
  71                         list_add(&border->head, &iface->ia_assignments);
  72                 }
  73
  74                 // Parse static entries
  75                 struct lease *lease;
  76                 list_for_each_entry(lease, &leases, head) {
  77                         // Construct entry
  78                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
  79                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
  80                         if (!a) {
  81                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  82                                         iface->ifname);
  83                                 return -1;
  84                         }
  85
  86                         if (lease->dhcpv4_leasetime > 0)
  87                                 a->leasetime = lease->dhcpv4_leasetime;
  88
  89                         a->clid_len = duid_len;
  90                         a->length = 128;
  91                         if (lease->hostid) {
  92                                 a->assigned = lease->hostid;
  93                         } else {
  94                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  95                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
  96                         }
  97                         odhcpd_urandom(a->key, sizeof(a->key));
  98                         memcpy(a->clid_data, lease->duid, lease->duid_len);
  99                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 100                         /* Static assignment */
 101                         a->flags |= OAF_STATIC;
 102                         /* Infinite valid */
 103                         a->valid_until = 0;
 104
 105                         // Assign to all interfaces
 106                         struct dhcpv6_assignment *c;
 107                         list_for_each_entry(c, &iface->ia_assignments, head) {
 108                                 if (c->length != 128 || c->assigned > a->assigned) {
 109                                         list_add_tail(&a->head, &c->head);
 110                                         break;
 111                                 } else if (c->assigned == a->assigned) {
 112                                         // Already an assignment with that number
 113                                         break;
 114                                 }
 115                         }
 116
 117                         if (a->head.next) {
 118                                 if (lease->hostname[0]) {
 119                                         free(a->hostname);
 120                                         a->hostname = strdup(lease->hostname);
 121                                 }
 122                         } else
 123                                 free_dhcpv6_assignment(a);
 124                 }
 125         }
 126         return 0;
 127 }
 128
 129 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
 130 {
 131         if (c->managed_sock.fd.registered) {
 132                 ustream_free(&c->managed_sock.stream);
 133                 close(c->managed_sock.fd.fd);
 134         }
 135
 136         if (c->head.next)
 137                 list_del(&c->head);
 138
 139         free(c->managed);
 140         free(c->hostname);
 141         free(c);
 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 void dhcpv6_write_statefile(void)
 208 {
 209         md5_ctx_t md5;
 210         md5_begin(&md5);
 211
 212         if (config.dhcp_statefile) {
 213                 time_t now = odhcpd_time(), wall_time = time(NULL);
 214                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 215                 if (fd < 0)
 216                         return;
 217
 218                 lockf(fd, F_LOCK, 0);
 219                 if (ftruncate(fd, 0) < 0) {}
 220
 221                 FILE *fp = fdopen(fd, "w");
 222                 if (!fp) {
 223                         close(fd);
 224                         return;
 225                 }
 226
 227                 struct interface *iface;
 228                 list_for_each_entry(iface, &interfaces, head) {
 229                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 230                                 continue;
 231
 232                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 233                                 struct dhcpv6_assignment *c;
 234                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 235                                         if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
 236                                                 continue;
 237
 238                                         char ipbuf[INET6_ADDRSTRLEN];
 239                                         char leasebuf[512];
 240                                         char duidbuf[264];
 241                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 242
 243                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 244                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
 245                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 246                                                         (c->hostname ? c->hostname : "-"),
 247                                                         (c->valid_until > now ?
 248                                                                 (c->valid_until - now + wall_time) :
 249                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 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 || (!INFINITE_VALID(c->valid_until) && 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                                         if (!(c->flags & OAF_BOUND))
 302                                                 continue;
 303
 304                                         char ipbuf[INET6_ADDRSTRLEN];
 305                                         char leasebuf[512];
 306                                         char duidbuf[16];
 307                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 308
 309                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 310                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
 311                                                         iface->ifname, duidbuf,
 312                                                         (c->hostname ? c->hostname : "-"),
 313                                                         (c->valid_until > now ?
 314                                                                 (c->valid_until - now + wall_time) :
 315                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 316                                                         c->addr);
 317
 318                                         struct in_addr addr = {htonl(c->addr)};
 319                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 320
 321                                         if (c->hostname) {
 322                                                 fputs(ipbuf, fp);
 323
 324                                                 char b[256];
 325                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 326                                                                 iface->search, b, sizeof(b)) > 0)
 327                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 328
 329                                                 fprintf(fp, "\t%s\n", c->hostname);
 330                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 331                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 332                                         }
 333
 334                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 335                                         leasebuf[l - 1] = '\n';
 336                                         fwrite(leasebuf, 1, l, fp);
 337                                 }
 338                         }
 339                 }
 340
 341                 fclose(fp);
 342         }
 343
 344         uint8_t newmd5[16];
 345         md5_end(newmd5, &md5);
 346
 347         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 348                 memcpy(statemd5, newmd5, sizeof(statemd5));
 349                 char *argv[2] = {config.dhcp_cb, NULL};
 350                 if (!vfork()) {
 351                         execv(argv[0], argv);
 352                         _exit(128);
 353                 }
 354         }
 355 }
 356
 357
 358 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 359 {
 360         if (a->length > 64 || a->managed_size < 0)
 361                 return;
 362
 363         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 364         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 365
 366         for (size_t i = 0; i < addrlen; ++i) {
 367                 struct in6_addr prefix = addrs[i].addr;
 368                 prefix.s6_addr32[1] |= htonl(a->assigned);
 369                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 370                                 iface, &a->peer.sin6_addr, 1024, add);
 371         }
 372 }
 373
 374 // More data was received from TCP connection
 375 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 376 {
 377         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 378         time_t now = odhcpd_time();
 379         bool first = c->managed_size < 0;
 380
 381         for (;;) {
 382                 int pending;
 383                 char *data = ustream_get_read_buf(s, &pending);
 384                 char *end = memmem(data, pending, "\n\n", 2);
 385
 386                 if (!end)
 387                         break;
 388
 389                 end += 2;
 390                 end[-1] = 0;
 391
 392                 c->managed_size = 0;
 393                 if (c->accept_reconf)
 394                         c->reconf_cnt = 1;
 395
 396                 char *saveptr;
 397                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 398                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 399                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 400
 401                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 402                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 403                                 continue;
 404
 405                         x = strtok_r(NULL, ",", &saveptr2);
 406                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 407                                 continue;
 408
 409                         x = strtok_r(NULL, ",", &saveptr2);
 410                         if (sscanf(x, "%u", &n->preferred) < 1)
 411                                 continue;
 412
 413                         x = strtok_r(NULL, ",", &saveptr2);
 414                         if (sscanf(x, "%u", &n->valid) < 1)
 415                                 continue;
 416
 417                         if (n->preferred > n->valid)
 418                                 continue;
 419
 420                         if (UINT32_MAX - now < n->preferred)
 421                                 n->preferred = UINT32_MAX;
 422                         else
 423                                 n->preferred += now;
 424
 425                         if (UINT32_MAX - now < n->valid)
 426                                 n->valid = UINT32_MAX;
 427                         else
 428                                 n->valid += now;
 429
 430                         n->dprefix = 0;
 431
 432                         ++c->managed_size;
 433                 }
 434
 435                 ustream_consume(s, end - data);
 436         }
 437
 438         if (first && c->managed_size == 0)
 439                 free_dhcpv6_assignment(c);
 440         else if (first)
 441                 c->valid_until = now + 150;
 442 }
 443
 444
 445 // TCP transmission has ended, either because of success or timeout or other error
 446 static void managed_handle_pd_done(struct ustream *s)
 447 {
 448         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 449         c->valid_until = odhcpd_time() + 15;
 450         c->managed_size = 0;
 451         if (c->accept_reconf)
 452                 c->reconf_cnt = 1;
 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 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 void dhcpv6_ia_preupdate(struct interface *iface)
 560 {
 561         if (iface->dhcpv6 != RELAYD_SERVER)
 562                 return;
 563
 564         struct dhcpv6_assignment *c, *border = list_last_entry(
 565                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 566         list_for_each_entry(c, &iface->ia_assignments, head)
 567                 if (c != border && !iface->managed)
 568                         apply_lease(iface, c, false);
 569 }
 570
 571 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 572 {
 573         if (iface->dhcpv6 != RELAYD_SERVER)
 574                 return;
 575
 576         int minprefix = -1;
 577         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 578                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 579                                 iface->ia_addr[i].prefix < 64 &&
 580                                 iface->ia_addr[i].prefix > minprefix)
 581                         minprefix = iface->ia_addr[i].prefix;
 582         }
 583
 584         struct dhcpv6_assignment *border = list_last_entry(
 585                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 586         if (minprefix > 32 && minprefix <= 64)
 587                 border->assigned = 1U << (64 - minprefix);
 588         else
 589                 border->assigned = 0;
 590
 591         struct list_head reassign = LIST_HEAD_INIT(reassign);
 592         struct dhcpv6_assignment *c, *d;
 593         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 594                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
 595                                 c->managed_size)
 596                         continue;
 597
 598                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 599                         list_move(&c->head, &reassign);
 600                 else if (c != border)
 601                         apply_lease(iface, c, true);
 602
 603                 if (c->accept_reconf && c->reconf_cnt == 0) {
 604                         c->reconf_cnt = 1;
 605                         c->reconf_sent = now;
 606                         send_reconf(iface, c);
 607
 608                         // Leave all other assignments of that client alone
 609                         struct dhcpv6_assignment *a;
 610                         list_for_each_entry(a, &iface->ia_assignments, head)
 611                                 if (a != c && a->clid_len == c->clid_len &&
 612                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 613                                         c->reconf_cnt = INT_MAX;
 614                 }
 615         }
 616
 617         while (!list_empty(&reassign)) {
 618                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 619                 list_del(&c->head);
 620                 if (!assign_pd(iface, c)) {
 621                         c->assigned = 0;
 622                         list_add(&c->head, &iface->ia_assignments);
 623                 }
 624         }
 625
 626         dhcpv6_write_statefile();
 627 }
 628
 629 static void reconf_timer(struct uloop_timeout *event)
 630 {
 631         time_t now = odhcpd_time();
 632         struct interface *iface;
 633         list_for_each_entry(iface, &interfaces, head) {
 634                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 635                         continue;
 636
 637                 struct dhcpv6_assignment *a, *n;
 638                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 639                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
 640                                 if ((a->length < 128 && a->clid_len > 0) ||
 641                                                 (a->length == 128 && a->clid_len == 0)) {
 642                                         list_del(&a->head);
 643                                         free_dhcpv6_assignment(a);
 644                                 }
 645                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 646                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 647                                 ++a->reconf_cnt;
 648                                 a->reconf_sent = now;
 649                                 send_reconf(iface, a);
 650                         }
 651                 }
 652         }
 653         uloop_timeout_set(event, 2000);
 654 }
 655
 656 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 657                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 658                 struct interface *iface, bool request)
 659 {
 660         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 661                 return 0;
 662
 663         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 664         size_t datalen = sizeof(out);
 665         time_t now = odhcpd_time();
 666
 667         if (status) {
 668                 struct __attribute__((packed)) {
 669                         uint16_t type;
 670                         uint16_t len;
 671                         uint16_t value;
 672                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 673                                 htons(status)};
 674
 675                 memcpy(buf + datalen, &stat, sizeof(stat));
 676                 datalen += sizeof(stat);
 677         } else {
 678                 if (a) {
 679                         uint32_t leasetime;
 680                         if (a->leasetime > 0) {
 681                                 leasetime = a->leasetime;
 682                         } else {
 683                                 leasetime = iface->dhcpv4_leasetime;
 684                         }
 685                         if (leasetime == 0)
 686                                 leasetime = 3600;
 687                         else if (leasetime < 60)
 688                                 leasetime = 60;
 689
 690                         uint32_t pref = leasetime;
 691                         uint32_t valid = leasetime;
 692
 693                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 694                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 695                         size_t m = 0;
 696
 697                         for (size_t i = 0; i < addrlen; ++i)
 698                                 if (addrs[i].preferred > addrs[m].preferred ||
 699                                                 (addrs[i].preferred == addrs[m].preferred &&
 700                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 701                                         m = i;
 702
 703                         for (size_t i = 0; i < addrlen; ++i) {
 704                                 uint32_t prefix_pref = addrs[i].preferred;
 705                                 uint32_t prefix_valid = addrs[i].valid;
 706
 707                                 if (addrs[i].prefix > 96 ||
 708                                                 addrs[i].preferred <= (uint32_t)now)
 709                                         continue;
 710
 711                                 if (prefix_pref != UINT32_MAX)
 712                                         prefix_pref -= now;
 713
 714                                 if (prefix_valid != UINT32_MAX)
 715                                         prefix_valid -= now;
 716
 717                                 if (a->length < 128) {
 718                                         struct dhcpv6_ia_prefix p = {
 719                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 720                                                 .len = htons(sizeof(p) - 4),
 721                                                 .preferred = htonl(prefix_pref),
 722                                                 .valid = htonl(prefix_valid),
 723                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 724                                                 .addr = addrs[i].addr
 725                                         };
 726                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 727
 728                                         size_t entrlen = sizeof(p) - 4;
 729
 730                                         if (datalen + entrlen + 4 > buflen ||
 731                                                         (a->assigned == 0 && a->managed_size == 0) ||
 732                                                         (!a->managed_size && a->length <= addrs[i].prefix))
 733                                                 continue;
 734
 735                                         memcpy(buf + datalen, &p, sizeof(p));
 736                                         datalen += entrlen + 4;
 737                                 } else {
 738                                         struct dhcpv6_ia_addr n = {
 739                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 740                                                 .len = htons(sizeof(n) - 4),
 741                                                 .addr = addrs[i].addr,
 742                                                 .preferred = htonl(prefix_pref),
 743                                                 .valid = htonl(prefix_valid)
 744                                         };
 745                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 746                                         size_t entrlen = sizeof(n) - 4;
 747
 748                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 749                                                         addrs[i].prefix <= 64)
 750                                                 continue;
 751
 752                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 753                                                 continue;
 754
 755                                         memcpy(buf + datalen, &n, sizeof(n));
 756                                         datalen += entrlen + 4;
 757                                 }
 758
 759                                 // Calculate T1 / T2 based on non-deprecated addresses
 760                                 if (prefix_pref > 0) {
 761                                         if (prefix_pref < pref)
 762                                                 pref = prefix_pref;
 763
 764                                         if (prefix_valid < valid)
 765                                                 valid = prefix_valid;
 766                                 }
 767                         }
 768
 769                         if (!INFINITE_VALID(a->valid_until))
 770                                 /* UINT32_MAX is considered as infinite leasetime */
 771                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 772
 773                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
 774                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 775
 776                         if (!out.t1)
 777                                 out.t1 = htonl(1);
 778
 779                         if (!out.t2)
 780                                 out.t2 = htonl(1);
 781                 }
 782
 783                 if (!request) {
 784                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 785                         uint16_t otype, olen;
 786                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 787                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 788                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 789                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 790                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 791                                         continue;
 792
 793                                 bool found = false;
 794                                 if (a) {
 795                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 796                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 797
 798                                         for (size_t i = 0; i < addrlen; ++i) {
 799                                                 if (addrs[i].prefix > 96 ||
 800                                                                 addrs[i].preferred <= (uint32_t)now)
 801                                                         continue;
 802
 803                                                 struct in6_addr addr = addrs[i].addr;
 804                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 805                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 806
 807                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 808                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 809                                                                 found = true;
 810                                                 } else {
 811                                                         addr.s6_addr32[3] = htonl(a->assigned);
 812
 813                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 814                                                                 found = true;
 815                                                 }
 816                                         }
 817                                 }
 818
 819                                 if (!found) {
 820                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 821                                                 struct dhcpv6_ia_prefix inv = {
 822                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 823                                                         .len = htons(sizeof(inv) - 4),
 824                                                         .preferred = 0,
 825                                                         .valid = 0,
 826                                                         .prefix = p->prefix,
 827                                                         .addr = p->addr
 828                                                 };
 829
 830                                                 if (datalen + sizeof(inv) > buflen)
 831                                                         continue;
 832
 833                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 834                                                 datalen += sizeof(inv);
 835                                         } else {
 836                                                 struct dhcpv6_ia_addr inv = {
 837                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 838                                                         .len = htons(sizeof(inv) - 4),
 839                                                         .addr = n->addr,
 840                                                         .preferred = 0,
 841                                                         .valid = 0
 842                                                 };
 843
 844                                                 if (datalen + sizeof(inv) > buflen)
 845                                                         continue;
 846
 847                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 848                                                 datalen += sizeof(inv);
 849                                         }
 850                                 }
 851                         }
 852                 }
 853         }
 854
 855         out.len = htons(datalen - 4);
 856         memcpy(buf, &out, sizeof(out));
 857         return datalen;
 858 }
 859
 860 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 861                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 862 {
 863         const char *type = "UNKNOWN";
 864         const char *status = "UNKNOWN";
 865
 866         if (msgtype == DHCPV6_MSG_RENEW)
 867                 return;
 868
 869         switch (msgtype) {
 870         case DHCPV6_MSG_SOLICIT:
 871                 type = "SOLICIT";
 872                 break;
 873         case DHCPV6_MSG_REQUEST:
 874                 type = "REQUEST";
 875                 break;
 876         case DHCPV6_MSG_CONFIRM:
 877                 type = "CONFIRM";
 878                 break;
 879         case DHCPV6_MSG_RENEW:
 880                 type = "RENEW";
 881                 break;
 882         case DHCPV6_MSG_REBIND:
 883                 type = "REBIND";
 884                 break;
 885         case DHCPV6_MSG_RELEASE:
 886                 type = "RELEASE";
 887                 break;
 888         case DHCPV6_MSG_DECLINE:
 889                 type = "DECLINE";
 890                 break;
 891         }
 892
 893         switch (code) {
 894         case DHCPV6_STATUS_OK:
 895                 status = "ok";
 896                 break;
 897         case DHCPV6_STATUS_NOADDRSAVAIL:
 898                 status = "no addresses available";
 899                 break;
 900         case DHCPV6_STATUS_NOBINDING:
 901                 status = "no binding";
 902                 break;
 903         case DHCPV6_STATUS_NOTONLINK:
 904                 status = "not on-link";
 905                 break;
 906         case DHCPV6_STATUS_NOPREFIXAVAIL:
 907                 status = "no prefix available";
 908                 break;
 909         }
 910
 911         char leasebuf[256] = "";
 912
 913         if (a) {
 914                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 915                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 916                 size_t lbsize = 0;
 917                 char addrbuf[INET6_ADDRSTRLEN];
 918
 919                 for (size_t i = 0; i < addrlen; ++i) {
 920                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 921                                 continue;
 922
 923                         struct in6_addr addr = addrs[i].addr;
 924                         int prefix = a->managed ? addrs[i].prefix : a->length;
 925                         if (prefix == 128)
 926                                 addr.s6_addr32[3] = htonl(a->assigned);
 927                         else
 928                                 addr.s6_addr32[1] |= htonl(a->assigned);
 929
 930                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 931                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 932                 }
 933         }
 934
 935         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 936                         duidbuf, iface->ifname, status, leasebuf);
 937 }
 938
 939 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 940                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 941 {
 942         time_t now = odhcpd_time();
 943         size_t response_len = 0;
 944         const struct dhcpv6_client_header *hdr = data;
 945         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 946         uint16_t otype, olen;
 947
 948         // Find and parse client-id and hostname
 949         bool accept_reconf = false;
 950         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 951         char hostname[256];
 952         size_t hostname_len = 0;
 953         bool notonlink = false;
 954         char duidbuf[261];
 955
 956         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 957                 if (otype == DHCPV6_OPT_CLIENTID) {
 958                         clid_data = odata;
 959                         clid_len = olen;
 960
 961                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 962                                 memcpy(mac, &odata[8], sizeof(mac));
 963                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 964                                 memcpy(mac, &odata[4], sizeof(mac));
 965
 966                         if (olen <= 130)
 967                                 odhcpd_hexlify(duidbuf, odata, olen);
 968                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 969                         uint8_t fqdn_buf[256];
 970                         memcpy(fqdn_buf, odata, olen);
 971                         fqdn_buf[olen++] = 0;
 972
 973                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 974                                 hostname_len = strcspn(hostname, ".");
 975                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 976                         accept_reconf = true;
 977                 }
 978         }
 979
 980         if (!clid_data || !clid_len || clid_len > 130)
 981                 goto out;
 982
 983         struct dhcpv6_assignment *first = NULL;
 984         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 985                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 986                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 987                 bool ia_addr_present = false;
 988                 if (!is_pd && !is_na)
 989                         continue;
 990
 991                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 992                 size_t ia_response_len = 0;
 993                 uint8_t reqlen = (is_pd) ? 62 : 128;
 994                 uint32_t reqhint = 0;
 995
 996                 // Parse request hint for IA-PD
 997                 if (is_pd) {
 998                         uint8_t *sdata;
 999                         uint16_t stype, slen;
1000                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1001                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1002                                         continue;
1003
1004                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1005                                 if (p->prefix) {
1006                                         reqlen = p->prefix;
1007                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1008                                         if (reqlen > 32 && reqlen <= 64)
1009                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1010                                 }
1011                         }
1012
1013                         if (reqlen > 64)
1014                                 reqlen = 64;
1015                 } else if (is_na) {
1016                         uint8_t *sdata;
1017                         uint16_t stype, slen;
1018                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1019                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1020                                         continue;
1021
1022                                 ia_addr_present = true;
1023                         }
1024                 }
1025
1026                 // Find assignment
1027                 struct dhcpv6_assignment *c, *a = NULL;
1028                 list_for_each_entry(c, &iface->ia_assignments, head) {
1029                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1030                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1031                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1032                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1033                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1034                                 a = c;
1035
1036                                 // Reset state
1037                                 apply_lease(iface, a, false);
1038                                 memcpy(a->clid_data, clid_data, clid_len);
1039                                 a->clid_len = clid_len;
1040                                 a->iaid = ia->iaid;
1041                                 a->peer = *addr;
1042                                 a->reconf_cnt = 0;
1043                                 a->reconf_sent = 0;
1044                                 break;
1045                         }
1046                 }
1047
1048                 // Generic message handling
1049                 uint16_t status = DHCPV6_STATUS_OK;
1050                 if (a && a->managed_size < 0) {
1051                         return -1;
1052                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1053                         bool assigned = !!a;
1054
1055                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1056                                 a = calloc(1, sizeof(*a) + clid_len);
1057                                 if (a) {
1058                                         a->clid_len = clid_len;
1059                                         a->iaid = ia->iaid;
1060                                         a->length = reqlen;
1061                                         a->peer = *addr;
1062                                         a->assigned = reqhint;
1063                                         // Set valid time to current time indicating
1064                                         // assignment is not having infinite lifetime
1065                                         a->valid_until = now;
1066
1067                                         if (first)
1068                                                 memcpy(a->key, first->key, sizeof(a->key));
1069                                         else
1070                                                 odhcpd_urandom(a->key, sizeof(a->key));
1071                                         memcpy(a->clid_data, clid_data, clid_len);
1072
1073                                         if (is_pd)
1074                                                 while (!(assigned = assign_pd(iface, a)) &&
1075                                                                 !a->managed_size && ++a->length <= 64);
1076                                         else
1077                                                 assigned = assign_na(iface, a);
1078
1079                                         if (a->managed_size && !assigned)
1080                                                 return -1;
1081                                 }
1082                         }
1083
1084                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1085                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1086                         } else if (assigned && !first) { //
1087                                 size_t handshake_len = 4;
1088                                 buf[0] = 0;
1089                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1090                                 buf[2] = 0;
1091                                 buf[3] = 0;
1092
1093                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1094                                         struct dhcpv6_auth_reconfigure auth = {
1095                                                 htons(DHCPV6_OPT_AUTH),
1096                                                 htons(sizeof(auth) - 4),
1097                                                 3, 1, 0,
1098                                                 {htonl(time(NULL)), htonl(++serial)},
1099                                                 1,
1100                                                 {0}
1101                                         };
1102                                         memcpy(auth.key, a->key, sizeof(a->key));
1103                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1104                                         handshake_len += sizeof(auth);
1105                                 }
1106
1107                                 buf += handshake_len;
1108                                 buflen -= handshake_len;
1109                                 response_len += handshake_len;
1110
1111                                 first = a;
1112                         }
1113
1114                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1115
1116                         // Was only a solicitation: mark binding for removal
1117                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1118                                 a->flags &= ~OAF_BOUND;
1119
1120                                 if (!(a->flags & OAF_STATIC))
1121                                         a->valid_until = now;
1122                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1123                                 if (hostname_len > 0) {
1124                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1125                                         if (a->hostname) {
1126                                                 memcpy(a->hostname, hostname, hostname_len);
1127                                                 a->hostname[hostname_len] = 0;
1128                                         }
1129                                 }
1130                                 a->accept_reconf = accept_reconf;
1131                                 a->flags |= OAF_BOUND;
1132                                 apply_lease(iface, a, true);
1133                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1134                                 free_dhcpv6_assignment(a);
1135                         }
1136                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1137                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1138                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1139                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1140                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1141                                 status = DHCPV6_STATUS_NOBINDING;
1142                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1143                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1144                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1145                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1146                                 if (a) {
1147                                         a->flags |= OAF_BOUND;
1148                                         apply_lease(iface, a, true);
1149                                 }
1150                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1151                                 if (!(a->flags & OAF_STATIC))
1152                                         a->valid_until = now - 1;
1153
1154                                 a->flags &= ~OAF_BOUND;
1155                                 apply_lease(iface, a, false);
1156                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1157                                 a->flags &= ~OAF_BOUND;
1158
1159                                 if (!(a->flags & OAF_STATIC)) {
1160                                         a->clid_len = 0;
1161                                         a->valid_until = now + 3600; // Block address for 1h
1162                                 }
1163                         }
1164                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1165                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1166                         status = DHCPV6_STATUS_NOTONLINK;
1167                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1168                         notonlink = true;
1169                 }
1170
1171                 buf += ia_response_len;
1172                 buflen -= ia_response_len;
1173                 response_len += ia_response_len;
1174                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1175         }
1176
1177         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1178                         response_len + 6 < buflen) {
1179                 buf[0] = 0;
1180                 buf[1] = DHCPV6_OPT_STATUS;
1181                 buf[2] = 0;
1182                 buf[3] = 2;
1183                 buf[4] = 0;
1184                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1185                 response_len += 6;
1186         }
1187
1188         dhcpv6_write_statefile();
1189
1190 out:
1191         return response_len;
1192 }