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                         a->clid_len = duid_len;
 104                         a->length = 128;
 105                         if (lease->hostid) {
 106                                 a->assigned = lease->hostid;
 107                         } else {
 108                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
 109                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 110                         }
 111                         odhcpd_urandom(a->key, sizeof(a->key));
 112                         memcpy(a->clid_data, lease->duid, a->clid_len);
 113                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 114
 115                         // Assign to all interfaces
 116                         struct dhcpv6_assignment *c;
 117                         list_for_each_entry(c, &iface->ia_assignments, head) {
 118                                 if (c->length != 128 || c->assigned > a->assigned) {
 119                                         list_add_tail(&a->head, &c->head);
 120                                         break;
 121                                 } else if (c->assigned == a->assigned) {
 122                                         // Already an assignment with that number
 123                                         break;
 124                                 }
 125                         }
 126
 127                         if (a->head.next) {
 128                                 if (lease->hostname[0]) {
 129                                         free(a->hostname);
 130                                         a->hostname = strdup(lease->hostname);
 131                                 }
 132                         } else {
 133                                 free(a->hostname);
 134                                 free(a);
 135                         }
 136                 }
 137         }
 138         return 0;
 139 }
 140
 141
 142 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 143 {
 144         struct {
 145                 struct dhcpv6_client_header hdr;
 146                 uint16_t srvid_type;
 147                 uint16_t srvid_len;
 148                 uint16_t duid_type;
 149                 uint16_t hardware_type;
 150                 uint8_t mac[6];
 151                 uint16_t msg_type;
 152                 uint16_t msg_len;
 153                 uint8_t msg_id;
 154                 struct dhcpv6_auth_reconfigure auth;
 155                 uint16_t clid_type;
 156                 uint16_t clid_len;
 157                 uint8_t clid_data[128];
 158         } __attribute__((packed)) reconf_msg = {
 159                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 160                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 161                 .srvid_len = htons(10),
 162                 .duid_type = htons(3),
 163                 .hardware_type = htons(1),
 164                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 165                 .msg_len = htons(1),
 166                 .msg_id = DHCPV6_MSG_RENEW,
 167                 .auth = {htons(DHCPV6_OPT_AUTH),
 168                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 169                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 170                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 171                 .clid_len = htons(assign->clid_len),
 172                 .clid_data = {0},
 173         };
 174
 175         odhcpd_get_mac(iface, reconf_msg.mac);
 176         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 177         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 178
 179         md5_ctx_t md5;
 180         uint8_t secretbytes[64];
 181         memset(secretbytes, 0, sizeof(secretbytes));
 182         memcpy(secretbytes, assign->key, sizeof(assign->key));
 183
 184         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 185                 secretbytes[i] ^= 0x36;
 186
 187         md5_begin(&md5);
 188         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 189         md5_hash(iov.iov_base, iov.iov_len, &md5);
 190         md5_end(reconf_msg.auth.key, &md5);
 191
 192         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 193                 secretbytes[i] ^= 0x36;
 194                 secretbytes[i] ^= 0x5c;
 195         }
 196
 197         md5_begin(&md5);
 198         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 199         md5_hash(reconf_msg.auth.key, 16, &md5);
 200         md5_end(reconf_msg.auth.key, &md5);
 201
 202         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 203 }
 204
 205
 206 void dhcpv6_write_statefile(void)
 207 {
 208         md5_ctx_t md5;
 209         md5_begin(&md5);
 210
 211         if (config.dhcp_statefile) {
 212                 time_t now = odhcpd_time(), wall_time = time(NULL);
 213                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 214                 if (fd < 0)
 215                         return;
 216
 217                 lockf(fd, F_LOCK, 0);
 218                 if (ftruncate(fd, 0) < 0) {}
 219
 220                 FILE *fp = fdopen(fd, "w");
 221                 if (!fp) {
 222                         close(fd);
 223                         return;
 224                 }
 225
 226                 struct interface *iface;
 227                 list_for_each_entry(iface, &interfaces, head) {
 228                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 229                                 continue;
 230
 231                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 232                                 struct dhcpv6_assignment *c;
 233                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 234                                         if (c->clid_len == 0 || c->managed_size < 0)
 235                                                 continue;
 236
 237                                         char ipbuf[INET6_ADDRSTRLEN];
 238                                         char leasebuf[512];
 239                                         char duidbuf[264];
 240                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 241
 242                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 243                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 244                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 245                                                         (c->hostname ? c->hostname : "-"),
 246                                                         (unsigned)(c->valid_until > now ?
 247                                                                         (c->valid_until - now + wall_time) : 0),
 248                                                         c->assigned, (unsigned)c->length);
 249
 250                                         struct in6_addr addr;
 251                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 252                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 253                                         size_t m = 0;
 254
 255                                         for (size_t i = 0; i < addrlen; ++i)
 256                                                 if (addrs[i].preferred > addrs[m].preferred ||
 257                                                                 (addrs[i].preferred == addrs[m].preferred &&
 258                                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 259                                                         m = i;
 260
 261                                         for (size_t i = 0; i < addrlen; ++i) {
 262                                                 if (addrs[i].prefix > 96 || c->valid_until <= now ||
 263                                                                 (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 264                                                                                 addrs[i].prefix == 64))
 265                                                         continue;
 266
 267                                                 addr = addrs[i].addr;
 268                                                 if (c->length == 128)
 269                                                         addr.s6_addr32[3] = htonl(c->assigned);
 270                                                 else
 271                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 272
 273                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 274
 275                                                 if (c->length == 128 && c->hostname) {
 276                                                         fputs(ipbuf, fp);
 277
 278                                                         char b[256];
 279                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 280                                                                         iface->search, b, sizeof(b)) > 0)
 281                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 282
 283                                                         fprintf(fp, "\t%s\n", c->hostname);
 284                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 285                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 286                                                 }
 287
 288                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 289                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 290                                         }
 291                                         leasebuf[l - 1] = '\n';
 292                                         fwrite(leasebuf, 1, l, fp);
 293                                 }
 294                         }
 295
 296                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 297                                 struct dhcpv4_assignment *c;
 298                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 299                                         char ipbuf[INET6_ADDRSTRLEN];
 300                                         char leasebuf[512];
 301                                         char duidbuf[16];
 302                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 303
 304                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 305                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 306                                                         iface->ifname, duidbuf,
 307                                                         (c->hostname ? c->hostname : "-"),
 308                                                         (unsigned)(c->valid_until > now ?
 309                                                                         (c->valid_until - now + wall_time) : 0),
 310                                                         c->addr);
 311
 312                                         struct in_addr addr = {htonl(c->addr)};
 313                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 314
 315                                         if (c->hostname[0]) {
 316                                                 fputs(ipbuf, fp);
 317
 318                                                 char b[256];
 319                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 320                                                                 iface->search, b, sizeof(b)) > 0)
 321                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 322
 323                                                 fprintf(fp, "\t%s\n", c->hostname);
 324                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 325                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 326                                         }
 327
 328                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 329                                         leasebuf[l - 1] = '\n';
 330                                         fwrite(leasebuf, 1, l, fp);
 331                                 }
 332                         }
 333                 }
 334
 335                 fclose(fp);
 336         }
 337
 338         uint8_t newmd5[16];
 339         md5_end(newmd5, &md5);
 340
 341         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 342                 memcpy(statemd5, newmd5, sizeof(statemd5));
 343                 char *argv[2] = {config.dhcp_cb, NULL};
 344                 if (!vfork()) {
 345                         execv(argv[0], argv);
 346                         _exit(128);
 347                 }
 348         }
 349 }
 350
 351
 352 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 353 {
 354         if (a->length > 64 || a->managed_size < 0)
 355                 return;
 356
 357         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 358         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 359
 360         for (size_t i = 0; i < addrlen; ++i) {
 361                 struct in6_addr prefix = addrs[i].addr;
 362                 prefix.s6_addr32[1] |= htonl(a->assigned);
 363                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 364                                 iface, &a->peer.sin6_addr, 1024, add);
 365         }
 366 }
 367
 368
 369 // More data was received from TCP connection
 370 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 371 {
 372         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 373         time_t now = odhcpd_time();
 374         bool first = c->managed_size < 0;
 375
 376         for (;;) {
 377                 int pending;
 378                 char *data = ustream_get_read_buf(s, &pending);
 379                 char *end = memmem(data, pending, "\n\n", 2);
 380
 381                 if (!end)
 382                         break;
 383
 384                 end += 2;
 385                 end[-1] = 0;
 386
 387                 c->managed_size = 0;
 388                 if (c->accept_reconf)
 389                         c->reconf_cnt = 1;
 390
 391                 char *saveptr;
 392                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 393                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 394                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 395
 396                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 397                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 398                                 continue;
 399
 400                         x = strtok_r(NULL, ",", &saveptr2);
 401                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 402                                 continue;
 403
 404                         x = strtok_r(NULL, ",", &saveptr2);
 405                         if (sscanf(x, "%u", &n->preferred) < 1)
 406                                 continue;
 407
 408                         x = strtok_r(NULL, ",", &saveptr2);
 409                         if (sscanf(x, "%u", &n->valid) < 1)
 410                                 continue;
 411
 412                         if (n->preferred > n->valid)
 413                                 continue;
 414
 415                         if (UINT32_MAX - now < n->preferred)
 416                                 n->preferred = UINT32_MAX;
 417                         else
 418                                 n->preferred += now;
 419
 420                         if (UINT32_MAX - now < n->valid)
 421                                 n->valid = UINT32_MAX;
 422                         else
 423                                 n->valid += now;
 424
 425                         n->dprefix = 0;
 426
 427                         ++c->managed_size;
 428                 }
 429
 430                 ustream_consume(s, end - data);
 431         }
 432
 433         if (first && c->managed_size == 0)
 434                 free_dhcpv6_assignment(c);
 435         else if (first)
 436                 c->valid_until = now + 150;
 437 }
 438
 439
 440 // TCP transmission has ended, either because of success or timeout or other error
 441 static void managed_handle_pd_done(struct ustream *s)
 442 {
 443         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 444         c->valid_until = odhcpd_time() + 15;
 445         c->managed_size = 0;
 446         if (c->accept_reconf)
 447                 c->reconf_cnt = 1;
 448 }
 449
 450
 451
 452 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 453 {
 454         struct dhcpv6_assignment *c;
 455
 456         if (iface->dhcpv6_pd_manager[0]) {
 457                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 458                 if (fd >= 0) {
 459                         char iaidbuf[298];
 460                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 461
 462                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 463                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 464                         ustream_fd_init(&assign->managed_sock, fd);
 465                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 466                                         iaidbuf, assign->iaid, assign->length);
 467                         ustream_write_pending(&assign->managed_sock.stream);
 468                         assign->managed_size = -1;
 469                         assign->valid_until = odhcpd_time() + 15;
 470                         list_add(&assign->head, &iface->ia_assignments);
 471
 472                         // Wait initial period of up to 250ms for immediate assignment
 473                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 474                         poll(&pfd, 1, 250);
 475                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 476
 477                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 478                                 return true;
 479                 }
 480
 481                 return false;
 482         } else if (iface->ia_addr_len < 1) {
 483                 return false;
 484         }
 485
 486         // Try honoring the hint first
 487         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 488         if (assign->assigned) {
 489                 list_for_each_entry(c, &iface->ia_assignments, head) {
 490                         if (c->length == 128 || c->length == 0)
 491                                 continue;
 492
 493                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 494                                 list_add_tail(&assign->head, &c->head);
 495                                 apply_lease(iface, assign, true);
 496                                 return true;
 497                         }
 498
 499                         if (c->assigned != 0)
 500                                 current = (c->assigned + (1 << (64 - c->length)));
 501                 }
 502         }
 503
 504         // Fallback to a variable assignment
 505         current = 1;
 506         list_for_each_entry(c, &iface->ia_assignments, head) {
 507                 if (c->length == 128 || c->length == 0)
 508                         continue;
 509
 510                 current = (current + asize) & (~asize);
 511                 if (current + asize < c->assigned) {
 512                         assign->assigned = current;
 513                         list_add_tail(&assign->head, &c->head);
 514                         apply_lease(iface, assign, true);
 515                         return true;
 516                 }
 517
 518                 if (c->assigned != 0)
 519                         current = (c->assigned + (1 << (64 - c->length)));
 520         }
 521
 522         return false;
 523 }
 524
 525
 526 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 527 {
 528         // Seed RNG with checksum of DUID
 529         uint32_t seed = 0;
 530         for (size_t i = 0; i < assign->clid_len; ++i)
 531                 seed += assign->clid_data[i];
 532         srand(seed);
 533
 534         // Try to assign up to 100x
 535         for (size_t i = 0; i < 100; ++i) {
 536                 uint32_t try;
 537                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 538
 539                 struct dhcpv6_assignment *c;
 540                 list_for_each_entry(c, &iface->ia_assignments, head) {
 541                         if (c->length == 0)
 542                                 continue;
 543
 544                         if (c->assigned > try || c->length != 128) {
 545                                 assign->assigned = try;
 546                                 list_add_tail(&assign->head, &c->head);
 547                                 return true;
 548                         } else if (c->assigned == try) {
 549                                 break;
 550                         }
 551                 }
 552         }
 553
 554         return false;
 555 }
 556
 557 void dhcpv6_ia_preupdate(struct interface *iface)
 558 {
 559         if (iface->dhcpv6 != RELAYD_SERVER)
 560                 return;
 561
 562         struct dhcpv6_assignment *c, *border = list_last_entry(
 563                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 564         list_for_each_entry(c, &iface->ia_assignments, head)
 565                 if (c != border && !iface->managed)
 566                         apply_lease(iface, c, false);
 567 }
 568
 569 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 570 {
 571         if (iface->dhcpv6 != RELAYD_SERVER)
 572                 return;
 573
 574         int minprefix = -1;
 575         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 576                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 577                                 iface->ia_addr[i].prefix < 64 &&
 578                                 iface->ia_addr[i].prefix > minprefix)
 579                         minprefix = iface->ia_addr[i].prefix;
 580         }
 581
 582         struct dhcpv6_assignment *border = list_last_entry(
 583                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 584         if (minprefix > 32 && minprefix <= 64)
 585                 border->assigned = 1U << (64 - minprefix);
 586         else
 587                 border->assigned = 0;
 588
 589         struct list_head reassign = LIST_HEAD_INIT(reassign);
 590         struct dhcpv6_assignment *c, *d;
 591         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 592                 if (c->clid_len == 0 || c->valid_until < now || c->managed_size)
 593                         continue;
 594
 595                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 596                         list_move(&c->head, &reassign);
 597                 else if (c != border)
 598                         apply_lease(iface, c, true);
 599
 600                 if (c->accept_reconf && c->reconf_cnt == 0) {
 601                         c->reconf_cnt = 1;
 602                         c->reconf_sent = now;
 603                         send_reconf(iface, c);
 604
 605                         // Leave all other assignments of that client alone
 606                         struct dhcpv6_assignment *a;
 607                         list_for_each_entry(a, &iface->ia_assignments, head)
 608                                 if (a != c && a->clid_len == c->clid_len &&
 609                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 610                                         c->reconf_cnt = INT_MAX;
 611                 }
 612         }
 613
 614         while (!list_empty(&reassign)) {
 615                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 616                 list_del(&c->head);
 617                 if (!assign_pd(iface, c)) {
 618                         c->assigned = 0;
 619                         list_add(&c->head, &iface->ia_assignments);
 620                 }
 621         }
 622
 623         dhcpv6_write_statefile();
 624 }
 625
 626
 627 static void reconf_timer(struct uloop_timeout *event)
 628 {
 629         time_t now = odhcpd_time();
 630         struct interface *iface;
 631         list_for_each_entry(iface, &interfaces, head) {
 632                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 633                         continue;
 634
 635                 struct dhcpv6_assignment *a, *n;
 636                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 637                         if (a->valid_until < now) {
 638                                 if ((a->length < 128 && a->clid_len > 0) ||
 639                                                 (a->length == 128 && a->clid_len == 0)) {
 640                                         list_del(&a->head);
 641                                         free_dhcpv6_assignment(a);
 642                                 }
 643                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 644                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 645                                 ++a->reconf_cnt;
 646                                 a->reconf_sent = now;
 647                                 send_reconf(iface, a);
 648                         }
 649                 }
 650         }
 651         uloop_timeout_set(event, 2000);
 652 }
 653
 654
 655 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 656                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 657                 struct interface *iface, bool request)
 658 {
 659         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 660                 return 0;
 661
 662         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 663         size_t datalen = sizeof(out);
 664         time_t now = odhcpd_time();
 665
 666         if (status) {
 667                 struct __attribute__((packed)) {
 668                         uint16_t type;
 669                         uint16_t len;
 670                         uint16_t value;
 671                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 672                                 htons(status)};
 673
 674                 memcpy(buf + datalen, &stat, sizeof(stat));
 675                 datalen += sizeof(stat);
 676         } else {
 677                 if (a) {
 678                         uint32_t leasetime = iface->dhcpv4_leasetime;
 679                         if (leasetime == 0)
 680                                 leasetime = 3600;
 681                         else if (leasetime < 60)
 682                                 leasetime = 60;
 683
 684                         uint32_t pref = leasetime;
 685                         uint32_t valid = leasetime;
 686
 687                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 688                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 689                         size_t m = 0;
 690
 691                         for (size_t i = 0; i < addrlen; ++i)
 692                                 if (addrs[i].preferred > addrs[m].preferred ||
 693                                                 (addrs[i].preferred == addrs[m].preferred &&
 694                                                                 memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 695                                         m = i;
 696
 697                         for (size_t i = 0; i < addrlen; ++i) {
 698                                 uint32_t prefix_pref = addrs[i].preferred;
 699                                 uint32_t prefix_valid = addrs[i].valid;
 700
 701                                 if (addrs[i].prefix > 96 ||
 702                                                 addrs[i].preferred <= (uint32_t)now)
 703                                         continue;
 704
 705                                 if (prefix_pref != UINT32_MAX)
 706                                         prefix_pref -= now;
 707
 708                                 if (prefix_valid != UINT32_MAX)
 709                                         prefix_valid -= now;
 710
 711                                 if (a->length < 128) {
 712                                         struct dhcpv6_ia_prefix p = {
 713                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 714                                                 .len = htons(sizeof(p) - 4),
 715                                                 .preferred = htonl(prefix_pref),
 716                                                 .valid = htonl(prefix_valid),
 717                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 718                                                 .addr = addrs[i].addr
 719                                         };
 720                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 721
 722                                         size_t entrlen = sizeof(p) - 4;
 723
 724                                         if (datalen + entrlen + 4 > buflen ||
 725                                                         (a->assigned == 0 && a->managed_size == 0) ||
 726                                                         (!a->managed_size && a->length <= addrs[i].prefix))
 727                                                 continue;
 728
 729                                         memcpy(buf + datalen, &p, sizeof(p));
 730                                         datalen += entrlen + 4;
 731                                 } else {
 732                                         struct dhcpv6_ia_addr n = {
 733                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 734                                                 .len = htons(sizeof(n) - 4),
 735                                                 .addr = addrs[i].addr,
 736                                                 .preferred = htonl(prefix_pref),
 737                                                 .valid = htonl(prefix_valid)
 738                                         };
 739                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 740                                         size_t entrlen = sizeof(n) - 4;
 741
 742                                         if (iface->managed < RELAYD_MANAGED_NO_AFLAG && i != m &&
 743                                                         addrs[i].prefix <= 64)
 744                                                 continue;
 745
 746                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 747                                                 continue;
 748
 749                                         memcpy(buf + datalen, &n, sizeof(n));
 750                                         datalen += entrlen + 4;
 751                                 }
 752
 753                                 // Calculate T1 / T2 based on non-deprecated addresses
 754                                 if (prefix_pref > 0) {
 755                                         if (prefix_pref < pref)
 756                                                 pref = prefix_pref;
 757
 758                                         if (prefix_valid < valid)
 759                                                 valid = prefix_valid;
 760                                 }
 761                         }
 762
 763                         a->valid_until = valid + now;
 764                         out.t1 = htonl(pref * 5 / 10);
 765                         out.t2 = htonl(pref * 8 / 10);
 766
 767                         if (!out.t1)
 768                                 out.t1 = htonl(1);
 769
 770                         if (!out.t2)
 771                                 out.t2 = htonl(1);
 772                 }
 773
 774                 if (!request) {
 775                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 776                         uint16_t otype, olen;
 777                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 778                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 779                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 780                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 781                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 782                                         continue;
 783
 784                                 bool found = false;
 785                                 if (a) {
 786                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 787                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 788
 789                                         for (size_t i = 0; i < addrlen; ++i) {
 790                                                 if (addrs[i].prefix > 96 ||
 791                                                                 addrs[i].preferred <= (uint32_t)now)
 792                                                         continue;
 793
 794                                                 struct in6_addr addr = addrs[i].addr;
 795                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 796                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 797
 798                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 799                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 800                                                                 found = true;
 801                                                 } else {
 802                                                         addr.s6_addr32[3] = htonl(a->assigned);
 803
 804                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 805                                                                 found = true;
 806                                                 }
 807                                         }
 808                                 }
 809
 810                                 if (!found) {
 811                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 812                                                 struct dhcpv6_ia_prefix inv = {
 813                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 814                                                         .len = htons(sizeof(inv) - 4),
 815                                                         .preferred = 0,
 816                                                         .valid = 0,
 817                                                         .prefix = p->prefix,
 818                                                         .addr = p->addr
 819                                                 };
 820
 821                                                 if (datalen + sizeof(inv) > buflen)
 822                                                         continue;
 823
 824                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 825                                                 datalen += sizeof(inv);
 826                                         } else {
 827                                                 struct dhcpv6_ia_addr inv = {
 828                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 829                                                         .len = htons(sizeof(inv) - 4),
 830                                                         .addr = n->addr,
 831                                                         .preferred = 0,
 832                                                         .valid = 0
 833                                                 };
 834
 835                                                 if (datalen + sizeof(inv) > buflen)
 836                                                         continue;
 837
 838                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 839                                                 datalen += sizeof(inv);
 840                                         }
 841                                 }
 842                         }
 843                 }
 844         }
 845
 846         out.len = htons(datalen - 4);
 847         memcpy(buf, &out, sizeof(out));
 848         return datalen;
 849 }
 850
 851
 852 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 853                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 854 {
 855         const char *type = "UNKNOWN";
 856         const char *status = "UNKNOWN";
 857
 858         if (msgtype == DHCPV6_MSG_RENEW)
 859                 return;
 860
 861         switch (msgtype) {
 862         case DHCPV6_MSG_SOLICIT:
 863                 type = "SOLICIT";
 864                 break;
 865         case DHCPV6_MSG_REQUEST:
 866                 type = "REQUEST";
 867                 break;
 868         case DHCPV6_MSG_CONFIRM:
 869                 type = "CONFIRM";
 870                 break;
 871         case DHCPV6_MSG_RENEW:
 872                 type = "RENEW";
 873                 break;
 874         case DHCPV6_MSG_REBIND:
 875                 type = "REBIND";
 876                 break;
 877         case DHCPV6_MSG_RELEASE:
 878                 type = "RELEASE";
 879                 break;
 880         case DHCPV6_MSG_DECLINE:
 881                 type = "DECLINE";
 882                 break;
 883         }
 884
 885         switch (code) {
 886         case DHCPV6_STATUS_OK:
 887                 status = "ok";
 888                 break;
 889         case DHCPV6_STATUS_NOADDRSAVAIL:
 890                 status = "no addresses available";
 891                 break;
 892         case DHCPV6_STATUS_NOBINDING:
 893                 status = "no binding";
 894                 break;
 895         case DHCPV6_STATUS_NOTONLINK:
 896                 status = "not on-link";
 897                 break;
 898         case DHCPV6_STATUS_NOPREFIXAVAIL:
 899                 status = "no prefix available";
 900                 break;
 901         }
 902
 903         char leasebuf[256] = "";
 904
 905         if (a) {
 906                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 907                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 908                 size_t lbsize = 0;
 909                 char addrbuf[INET6_ADDRSTRLEN];
 910
 911                 for (size_t i = 0; i < addrlen; ++i) {
 912                         if (addrs[i].prefix > 96 || addrs[i].preferred <= (uint32_t)now)
 913                                 continue;
 914
 915                         struct in6_addr addr = addrs[i].addr;
 916                         int prefix = a->managed ? addrs[i].prefix : a->length;
 917                         if (prefix == 128)
 918                                 addr.s6_addr32[3] = htonl(a->assigned);
 919                         else
 920                                 addr.s6_addr32[1] |= htonl(a->assigned);
 921
 922                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 923                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 924                 }
 925         }
 926
 927         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 928                         duidbuf, iface->ifname, status, leasebuf);
 929 }
 930
 931
 932
 933 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 934                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 935 {
 936         time_t now = odhcpd_time();
 937         size_t response_len = 0;
 938         const struct dhcpv6_client_header *hdr = data;
 939         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 940         uint16_t otype, olen;
 941
 942         // Find and parse client-id and hostname
 943         bool accept_reconf = false;
 944         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 945         char hostname[256];
 946         size_t hostname_len = 0;
 947         bool notonlink = false;
 948         char duidbuf[261];
 949
 950         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 951                 if (otype == DHCPV6_OPT_CLIENTID) {
 952                         clid_data = odata;
 953                         clid_len = olen;
 954
 955                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 956                                 memcpy(mac, &odata[8], sizeof(mac));
 957                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 958                                 memcpy(mac, &odata[4], sizeof(mac));
 959
 960                         if (olen <= 130)
 961                                 odhcpd_hexlify(duidbuf, odata, olen);
 962                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 963                         uint8_t fqdn_buf[256];
 964                         memcpy(fqdn_buf, odata, olen);
 965                         fqdn_buf[olen++] = 0;
 966
 967                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 968                                 hostname_len = strcspn(hostname, ".");
 969                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 970                         accept_reconf = true;
 971                 }
 972         }
 973
 974         if (!clid_data || !clid_len || clid_len > 130)
 975                 goto out;
 976
 977         struct dhcpv6_assignment *first = NULL;
 978         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 979                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 980                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 981                 bool ia_addr_present = false;
 982                 if (!is_pd && !is_na)
 983                         continue;
 984
 985                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 986                 size_t ia_response_len = 0;
 987                 uint8_t reqlen = (is_pd) ? 62 : 128;
 988                 uint32_t reqhint = 0;
 989
 990                 // Parse request hint for IA-PD
 991                 if (is_pd) {
 992                         uint8_t *sdata;
 993                         uint16_t stype, slen;
 994                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 995                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 996                                         continue;
 997
 998                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 999                                 if (p->prefix) {
1000                                         reqlen = p->prefix;
1001                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1002                                         if (reqlen > 32 && reqlen <= 64)
1003                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1004                                 }
1005                         }
1006
1007                         if (reqlen > 64)
1008                                 reqlen = 64;
1009                 } else if (is_na) {
1010                         uint8_t *sdata;
1011                         uint16_t stype, slen;
1012                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1013                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1014                                         continue;
1015
1016                                 ia_addr_present = true;
1017                         }
1018                 }
1019
1020                 // Find assignment
1021                 struct dhcpv6_assignment *c, *a = NULL;
1022                 list_for_each_entry(c, &iface->ia_assignments, head) {
1023                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1024                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1025                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1026                                         (c->iaid == ia->iaid || c->valid_until < now) &&
1027                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1028                                 a = c;
1029
1030                                 // Reset state
1031                                 apply_lease(iface, a, false);
1032                                 memcpy(a->clid_data, clid_data, clid_len);
1033                                 a->clid_len = clid_len;
1034                                 a->iaid = ia->iaid;
1035                                 a->peer = *addr;
1036                                 a->reconf_cnt = 0;
1037                                 a->reconf_sent = 0;
1038                                 break;
1039                         }
1040                 }
1041
1042                 // Generic message handling
1043                 uint16_t status = DHCPV6_STATUS_OK;
1044                 if (a && a->managed_size < 0) {
1045                         return -1;
1046                 } else if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1047                         bool assigned = !!a;
1048
1049                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
1050                                 a = calloc(1, sizeof(*a) + clid_len);
1051                                 if (a) {
1052                                         a->clid_len = clid_len;
1053                                         a->iaid = ia->iaid;
1054                                         a->length = reqlen;
1055                                         a->peer = *addr;
1056                                         a->assigned = reqhint;
1057
1058                                         if (first)
1059                                                 memcpy(a->key, first->key, sizeof(a->key));
1060                                         else
1061                                                 odhcpd_urandom(a->key, sizeof(a->key));
1062                                         memcpy(a->clid_data, clid_data, clid_len);
1063
1064                                         if (is_pd)
1065                                                 while (!(assigned = assign_pd(iface, a)) &&
1066                                                                 !a->managed_size && ++a->length <= 64);
1067                                         else
1068                                                 assigned = assign_na(iface, a);
1069
1070                                         if (a->managed_size && !assigned)
1071                                                 return -1;
1072                                 }
1073                         }
1074
1075                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
1076                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1077                         } else if (assigned && !first) { //
1078                                 size_t handshake_len = 4;
1079                                 buf[0] = 0;
1080                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1081                                 buf[2] = 0;
1082                                 buf[3] = 0;
1083
1084                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1085                                         struct dhcpv6_auth_reconfigure auth = {
1086                                                 htons(DHCPV6_OPT_AUTH),
1087                                                 htons(sizeof(auth) - 4),
1088                                                 3, 1, 0,
1089                                                 {htonl(time(NULL)), htonl(++serial)},
1090                                                 1,
1091                                                 {0}
1092                                         };
1093                                         memcpy(auth.key, a->key, sizeof(a->key));
1094                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1095                                         handshake_len += sizeof(auth);
1096                                 }
1097
1098                                 buf += handshake_len;
1099                                 buflen -= handshake_len;
1100                                 response_len += handshake_len;
1101
1102                                 first = a;
1103                         }
1104
1105                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1106
1107                         // Was only a solicitation: mark binding for removal
1108                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1109                                 a->valid_until = 0;
1110                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1111                                 if (hostname_len > 0) {
1112                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1113                                         if (a->hostname) {
1114                                                 memcpy(a->hostname, hostname, hostname_len);
1115                                                 a->hostname[hostname_len] = 0;
1116                                         }
1117                                 }
1118                                 a->accept_reconf = accept_reconf;
1119                                 apply_lease(iface, a, true);
1120                         } else if (!assigned && a && a->managed_size == 0) { // Cleanup failed assignment
1121                                 free_dhcpv6_assignment(a);
1122                         }
1123                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1124                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1125                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1126                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1127                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1128                                 status = DHCPV6_STATUS_NOBINDING;
1129                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1130                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1131                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1132                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1133                                 if (a)
1134                                         apply_lease(iface, a, true);
1135                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1136                                 a->valid_until = 0;
1137                                 apply_lease(iface, a, false);
1138                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1139                                 a->clid_len = 0;
1140                                 a->valid_until = now + 3600; // Block address for 1h
1141                         }
1142                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1143                         // Send NOTONLINK for CONFIRM with addr present so that clients restart connection
1144                         status = DHCPV6_STATUS_NOTONLINK;
1145                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1146                         notonlink = true;
1147                 }
1148
1149                 buf += ia_response_len;
1150                 buflen -= ia_response_len;
1151                 response_len += ia_response_len;
1152                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1153         }
1154
1155         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1156                         response_len + 6 < buflen) {
1157                 buf[0] = 0;
1158                 buf[1] = DHCPV6_OPT_STATUS;
1159                 buf[2] = 0;
1160                 buf[3] = 2;
1161                 buf[4] = 0;
1162                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1163                 response_len += 6;
1164         }
1165
1166         dhcpv6_write_statefile();
1167
1168 out:
1169         return response_len;
1170 }