src/dhcpv6-ia.c

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