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 < 64 &&
 585                                 addr[i].prefix > minprefix)
 586                         minprefix = addr[i].prefix;
 587
 588                 addr[i].addr.s6_addr32[3] = 0;
 589
 590                 if (addr[i].preferred < UINT32_MAX - now)
 591                         addr[i].preferred += now;
 592
 593                 if (addr[i].valid < UINT32_MAX - now)
 594                         addr[i].valid += now;
 595         }
 596
 597         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 598         if (minprefix > 32 && minprefix <= 64)
 599                 border->assigned = 1U << (64 - minprefix);
 600         else
 601                 border->assigned = 0;
 602
 603         bool change = len != (int)iface->ia_addr_len;
 604         for (int i = 0; !change && i < len; ++i)
 605                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 606                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 607                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 608                                 (addr[i].valid > (uint32_t)now + 7200) !=
 609                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 610                         change = true;
 611
 612         if (change) {
 613                 struct dhcpv6_assignment *c;
 614                 list_for_each_entry(c, &iface->ia_assignments, head)
 615                         if (c != border && !iface->managed)
 616                                 apply_lease(iface, c, false);
 617         }
 618
 619         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 620         iface->ia_addr_len = len;
 621
 622         if (change) { // Addresses / prefixes have changed
 623                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 624                 struct dhcpv6_assignment *c, *d;
 625                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 626                         if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 627                                 continue;
 628
 629                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 630                                 list_move(&c->head, &reassign);
 631                         else if (c != border)
 632                                 apply_lease(iface, c, true);
 633
 634                         if (c->accept_reconf && c->reconf_cnt == 0) {
 635                                 c->reconf_cnt = 1;
 636                                 c->reconf_sent = now;
 637                                 send_reconf(iface, c);
 638
 639                                 // Leave all other assignments of that client alone
 640                                 struct dhcpv6_assignment *a;
 641                                 list_for_each_entry(a, &iface->ia_assignments, head)
 642                                         if (a != c && a->clid_len == c->clid_len &&
 643                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 644                                                 c->reconf_cnt = INT_MAX;
 645                         }
 646                 }
 647
 648                 while (!list_empty(&reassign)) {
 649                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 650                         list_del(&c->head);
 651                         if (!assign_pd(iface, c)) {
 652                                 c->assigned = 0;
 653                                 list_add(&c->head, &iface->ia_assignments);
 654                         }
 655                 }
 656
 657                 dhcpv6_write_statefile();
 658         }
 659 }
 660
 661
 662 static void reconf_timer(struct uloop_timeout *event)
 663 {
 664         time_t now = odhcpd_time();
 665         struct interface *iface;
 666         list_for_each_entry(iface, &interfaces, head) {
 667                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 668                         continue;
 669
 670                 struct dhcpv6_assignment *a, *n;
 671                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 672                         if (a->valid_until < now) {
 673                                 if ((a->length < 128 && a->clid_len > 0) ||
 674                                                 (a->length == 128 && a->clid_len == 0)) {
 675                                         list_del(&a->head);
 676                                         free_dhcpv6_assignment(a);
 677                                 }
 678                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 679                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 680                                 ++a->reconf_cnt;
 681                                 a->reconf_sent = now;
 682                                 send_reconf(iface, a);
 683                         }
 684                 }
 685         }
 686         uloop_timeout_set(event, 2000);
 687 }
 688
 689
 690 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 691                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 692                 struct interface *iface, bool request)
 693 {
 694         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 695                 return 0;
 696
 697         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 698         size_t datalen = sizeof(out);
 699         time_t now = odhcpd_time();
 700
 701         if (status) {
 702                 struct __attribute__((packed)) {
 703                         uint16_t type;
 704                         uint16_t len;
 705                         uint16_t value;
 706                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 707                                 htons(status)};
 708
 709                 memcpy(buf + datalen, &stat, sizeof(stat));
 710                 datalen += sizeof(stat);
 711         } else {
 712                 if (a) {
 713                         uint32_t leasetime = iface->dhcpv4_leasetime;
 714                         if (leasetime == 0)
 715                                 leasetime = 3600;
 716                         else if (leasetime < 60)
 717                                 leasetime = 60;
 718
 719                         uint32_t pref = leasetime;
 720                         uint32_t valid = leasetime;
 721
 722                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 723                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 724                         size_t m = 0;
 725
 726                         for (size_t i = 0; i < addrlen; ++i)
 727                                 if (addrs[i].preferred > addrs[m].preferred ||
 728                                                 (addrs[i].preferred == addrs[m].preferred &&
 729                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 730                                         m = i;
 731
 732                         for (size_t i = 0; i < addrlen; ++i) {
 733                                 uint32_t prefix_pref = addrs[i].preferred;
 734                                 uint32_t prefix_valid = addrs[i].valid;
 735
 736                                 if (addrs[i].prefix > 96 ||
 737                                                 addrs[i].preferred <= (uint32_t)now)
 738                                         continue;
 739
 740                                 if (prefix_pref != UINT32_MAX)
 741                                         prefix_pref -= now;
 742
 743                                 if (prefix_valid != UINT32_MAX)
 744                                         prefix_valid -= now;
 745
 746                                 if (a->length < 128) {
 747                                         struct dhcpv6_ia_prefix p = {
 748                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 749                                                 .len = htons(sizeof(p) - 4),
 750                                                 .preferred = htonl(prefix_pref),
 751                                                 .valid = htonl(prefix_valid),
 752                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 753                                                 .addr = addrs[i].addr
 754                                         };
 755                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 756
 757                                         size_t entrlen = sizeof(p) - 4;
 758
 759                                         if (datalen + entrlen + 4 > buflen ||
 760                                                         (a->assigned == 0 && a->managed_size == 0) ||
 761                                                         (!a->managed_size && a->length < p.preferred))
 762                                                 continue;
 763
 764                                         memcpy(buf + datalen, &p, sizeof(p));
 765                                         datalen += entrlen + 4;
 766                                 } else {
 767                                         struct dhcpv6_ia_addr n = {
 768                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 769                                                 .len = htons(sizeof(n) - 4),
 770                                                 .addr = addrs[i].addr,
 771                                                 .preferred = htonl(prefix_pref),
 772                                                 .valid = htonl(prefix_valid)
 773                                         };
 774                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 775                                         size_t entrlen = sizeof(n) - 4;
 776
 777                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 778                                                         addrs[i].prefix == 64)
 779                                                 continue;
 780
 781                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 782                                                 continue;
 783
 784                                         memcpy(buf + datalen, &n, sizeof(n));
 785                                         datalen += entrlen + 4;
 786                                 }
 787
 788                                 // Calculate T1 / T2 based on non-deprecated addresses
 789                                 if (prefix_pref > 0) {
 790                                         if (prefix_pref < pref)
 791                                                 pref = prefix_pref;
 792
 793                                         if (prefix_valid < valid)
 794                                                 valid = prefix_valid;
 795                                 }
 796                         }
 797
 798                         a->valid_until = valid + now;
 799                         out.t1 = htonl(pref * 5 / 10);
 800                         out.t2 = htonl(pref * 8 / 10);
 801
 802                         if (!out.t1)
 803                                 out.t1 = htonl(1);
 804
 805                         if (!out.t2)
 806                                 out.t2 = htonl(1);
 807                 }
 808
 809                 if (!request) {
 810                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 811                         uint16_t otype, olen;
 812                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 813                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 814                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 815                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 816                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 817                                         continue;
 818
 819                                 bool found = false;
 820                                 if (a) {
 821                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 822                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 823
 824                                         for (size_t i = 0; i < addrlen; ++i) {
 825                                                 if (addrs[i].prefix > 96 ||
 826                                                                 addrs[i].preferred <= (uint32_t)now)
 827                                                         continue;
 828
 829                                                 struct in6_addr addr = addrs[i].addr;
 830                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 831                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 832
 833                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 834                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 835                                                                 found = true;
 836                                                 } else {
 837                                                         addr.s6_addr32[3] = htonl(a->assigned);
 838
 839                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 840                                                                 found = true;
 841                                                 }
 842                                         }
 843                                 }
 844
 845                                 if (!found) {
 846                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 847                                                 struct dhcpv6_ia_prefix inv = {
 848                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 849                                                         .len = htons(sizeof(inv) - 4),
 850                                                         .preferred = 0,
 851                                                         .valid = 0,
 852                                                         .prefix = p->prefix,
 853                                                         .addr = p->addr
 854                                                 };
 855
 856                                                 if (datalen + sizeof(inv) > buflen)
 857                                                         continue;
 858
 859                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 860                                                 datalen += sizeof(inv);
 861                                         } else {
 862                                                 struct dhcpv6_ia_addr inv = {
 863                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 864                                                         .len = htons(sizeof(inv) - 4),
 865                                                         .addr = n->addr,
 866                                                         .preferred = 0,
 867                                                         .valid = 0
 868                                                 };
 869
 870                                                 if (datalen + sizeof(inv) > buflen)
 871                                                         continue;
 872
 873                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 874                                                 datalen += sizeof(inv);
 875                                         }
 876                                 }
 877                         }
 878                 }
 879         }
 880
 881         out.len = htons(datalen - 4);
 882         memcpy(buf, &out, sizeof(out));
 883         return datalen;
 884 }
 885
 886
 887 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 888                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 889 {
 890         const char *type = "UNKNOWN";
 891         const char *status = "UNKNOWN";
 892
 893         if (msgtype == DHCPV6_MSG_RENEW)
 894                 return;
 895
 896         switch (msgtype) {
 897         case DHCPV6_MSG_SOLICIT:
 898                 type = "SOLICIT";
 899                 break;
 900         case DHCPV6_MSG_REQUEST:
 901                 type = "REQUEST";
 902                 break;
 903         case DHCPV6_MSG_CONFIRM:
 904                 type = "CONFIRM";
 905                 break;
 906         case DHCPV6_MSG_RENEW:
 907                 type = "RENEW";
 908                 break;
 909         case DHCPV6_MSG_REBIND:
 910                 type = "REBIND";
 911                 break;
 912         case DHCPV6_MSG_RELEASE:
 913                 type = "RELEASE";
 914                 break;
 915         case DHCPV6_MSG_DECLINE:
 916                 type = "DECLINE";
 917                 break;
 918         }
 919
 920         switch (code) {
 921         case DHCPV6_STATUS_OK:
 922                 status = "ok";
 923                 break;
 924         case DHCPV6_STATUS_NOADDRSAVAIL:
 925                 status = "no addresses available";
 926                 break;
 927         case DHCPV6_STATUS_NOBINDING:
 928                 status = "no binding";
 929                 break;
 930         case DHCPV6_STATUS_NOTONLINK:
 931                 status = "not on-link";
 932                 break;
 933         case DHCPV6_STATUS_NOPREFIXAVAIL:
 934                 status = "no prefix available";
 935                 break;
 936         }
 937
 938         char leasebuf[256] = "";
 939
 940         if (a) {
 941                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 942                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 943                 size_t lbsize = 0;
 944                 char addrbuf[INET6_ADDRSTRLEN];
 945
 946                 for (size_t i = 0; i < addrlen; ++i) {
 947                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 948                                 continue;
 949
 950                         struct in6_addr addr = addrs[i].addr;
 951                         int prefix = a->managed ? addrs[i].prefix : a->length;
 952                         if (prefix == 128)
 953                                 addr.s6_addr32[3] = htonl(a->assigned);
 954                         else
 955                                 addr.s6_addr32[1] |= htonl(a->assigned);
 956
 957                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 958                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 959                 }
 960         }
 961
 962         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 963                         duidbuf, iface->ifname, status, leasebuf);
 964 }
 965
 966
 967
 968 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 969                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 970 {
 971         time_t now = odhcpd_time();
 972         size_t response_len = 0;
 973         const struct dhcpv6_client_header *hdr = data;
 974         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 975         uint16_t otype, olen;
 976
 977         // Find and parse client-id and hostname
 978         bool accept_reconf = false;
 979         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 980         char hostname[256];
 981         size_t hostname_len = 0;
 982         bool notonlink = false;
 983         char duidbuf[261];
 984
 985         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 986                 if (otype == DHCPV6_OPT_CLIENTID) {
 987                         clid_data = odata;
 988                         clid_len = olen;
 989
 990                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 991                                 memcpy(mac, &odata[8], sizeof(mac));
 992                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 993                                 memcpy(mac, &odata[4], sizeof(mac));
 994
 995                         if (olen <= 130)
 996                                 odhcpd_hexlify(duidbuf, odata, olen);
 997                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 998                         uint8_t fqdn_buf[256];
 999                         memcpy(fqdn_buf, odata, olen);
1000                         fqdn_buf[olen++] = 0;
1001
1002                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
1003                                 hostname_len = strcspn(hostname, ".");
1004                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
1005                         accept_reconf = true;
1006                 }
1007         }
1008
1009         if (!clid_data || !clid_len || clid_len > 130)
1010                 goto out;
1011
1012         update(iface);
1013
1014         struct dhcpv6_assignment *first = NULL;
1015         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1016                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1017                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1018                 bool ia_addr_present = false;
1019                 if (!is_pd && !is_na)
1020                         continue;
1021
1022                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1023                 size_t ia_response_len = 0;
1024                 uint8_t reqlen = (is_pd) ? 62 : 128;
1025                 uint32_t reqhint = 0;
1026
1027                 // Parse request hint for IA-PD
1028                 if (is_pd) {
1029                         uint8_t *sdata;
1030                         uint16_t stype, slen;
1031                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1032                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1033                                         continue;
1034
1035                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1036                                 if (p->prefix) {
1037                                         reqlen = p->prefix;
1038                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1039                                         if (reqlen > 32 && reqlen <= 64)
1040                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1041                                 }
1042                         }
1043
1044                         if (reqlen > 64)
1045                                 reqlen = 64;
1046                 } else if (is_na) {
1047                         uint8_t *sdata;
1048                         uint16_t stype, slen;
1049                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1050                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1051                                         continue;
1052
1053                                 ia_addr_present = true;
1054                         }
1055                 }
1056
1057                 // Find assignment
1058                 struct dhcpv6_assignment *c, *a = NULL;
1059                 list_for_each_entry(c, &iface->ia_assignments, head) {
1060                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1061                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1062                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1063                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1064                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1065                                 a = c;
1066
1067                                 // Reset state
1068                                 apply_lease(iface, a, false);
1069                                 memcpy(a->clid_data, clid_data, clid_len);
1070                                 a->clid_len = clid_len;
1071                                 a->iaid = ia->iaid;
1072                                 a->peer = *addr;
1073                                 a->reconf_cnt = 0;
1074                                 a->reconf_sent = 0;
1075                                 break;
1076                         }
1077                 }
1078
1079                 // Generic message handling
1080                 uint16_t status = DHCPV6_STATUS_OK;
1081                 if (a && a->managed_size < 0) {
1082                         return -1;
1083                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1084                         bool assigned = !!a;
1085
1086                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1087                                 a = calloc(1, sizeof(*a) + clid_len);
1088                                 if (a) {
1089                                         a->clid_len = clid_len;
1090                                         a->iaid = ia->iaid;
1091                                         a->length = reqlen;
1092                                         a->peer = *addr;
1093                                         a->assigned = reqhint;
1094
1095                                         if (first)
1096                                                 memcpy(a->key, first->key, sizeof(a->key));
1097                                         else
1098                                                 odhcpd_urandom(a->key, sizeof(a->key));
1099                                         memcpy(a->clid_data, clid_data, clid_len);
1100
1101                                         if (is_pd)
1102                                                 while (!(assigned = assign_pd(iface, a)) &&
1103                                                                 !a->managed_size && ++a->length <= 64);
1104                                         else
1105                                                 assigned = assign_na(iface, a);
1106
1107                                         if (a->managed_size && !assigned)
1108                                                 return -1;
1109                                 }
1110                         }
1111
1112                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1113                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1114                         } else if (assigned && !first) { //
1115                                 size_t handshake_len = 4;
1116                                 buf[0] = 0;
1117                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1118                                 buf[2] = 0;
1119                                 buf[3] = 0;
1120
1121                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1122                                         struct dhcpv6_auth_reconfigure auth = {
1123                                                 htons(DHCPV6_OPT_AUTH),
1124                                                 htons(sizeof(auth) - 4),
1125                                                 3, 1, 0,
1126                                                 {htonl(time(NULL)), htonl(++serial)},
1127                                                 1,
1128                                                 {0}
1129                                         };
1130                                         memcpy(auth.key, a->key, sizeof(a->key));
1131                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1132                                         handshake_len += sizeof(auth);
1133                                 }
1134
1135                                 buf += handshake_len;
1136                                 buflen -= handshake_len;
1137                                 response_len += handshake_len;
1138
1139                                 first = a;
1140                         }
1141
1142                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1143
1144                         // Was only a solicitation: mark binding for removal
1145                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1146                                 a->valid_until = 0;
1147                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1148                                 if (hostname_len > 0) {
1149                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1150                                         if (a->hostname) {
1151                                                 memcpy(a->hostname, hostname, hostname_len);
1152                                                 a->hostname[hostname_len] = 0;
1153                                         }
1154                                 }
1155                                 a->accept_reconf = accept_reconf;
1156                                 apply_lease(iface, a, true);
1157                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1158                                 free_dhcpv6_assignment(a);
1159                         }
1160                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1161                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1162                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1163                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1164                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1165                                 status = DHCPV6_STATUS_NOBINDING;
1166                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1167                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1168                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1169                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1170                                 if (a)
1171                                         apply_lease(iface, a, true);
1172                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1173                                 a->valid_until = 0;
1174                                 apply_lease(iface, a, false);
1175                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1176                                 a->clid_len = 0;
1177                                 a->valid_until = now + 3600; // Block address for 1h
1178                         }
1179                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1180                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1181                         status = DHCPV6_STATUS_NOTONLINK;
1182                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1183                         notonlink = true;
1184                 }
1185
1186                 buf += ia_response_len;
1187                 buflen -= ia_response_len;
1188                 response_len += ia_response_len;
1189                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1190         }
1191
1192         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1193                         response_len + 6 < buflen) {
1194                 buf[0] = 0;
1195                 buf[1] = DHCPV6_OPT_STATUS;
1196                 buf[2] = 0;
1197                 buf[3] = 2;
1198                 buf[4] = 0;
1199                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1200                 response_len += 6;
1201         }
1202
1203         dhcpv6_write_statefile();
1204
1205 out:
1206         return response_len;
1207 }