src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2016 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include "odhcpd.h"
  17 #include "dhcpv6.h"
  18 #include "dhcpv4.h"
  19 #include "libubox/md5.h"
  20 #include "libubox/usock.h"
  21
  22 #include <time.h>
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <stdio.h>
  26 #include <poll.h>
  27 #include <alloca.h>
  28 #include <resolv.h>
  29 #include <limits.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <stdbool.h>
  34 #include <arpa/inet.h>
  35 #include <sys/timerfd.h>
  36
  37 #define ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) \
  38     ((iface)->managed == RELAYD_MANAGED_NO_AFLAG || (i) == (m) || \
  39      (addrs)[(i)].prefix > 64)
  40
  41 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
  42 static void reconf_timer(struct uloop_timeout *event);
  43 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  44 static uint32_t serial = 0;
  45 static uint8_t statemd5[16];
  46
  47 int dhcpv6_ia_init(void)
  48 {
  49         uloop_timeout_set(&reconf_event, 2000);
  50         return 0;
  51 }
  52
  53 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  54 {
  55         if (!enable && iface->ia_assignments.next) {
  56                 struct dhcpv6_assignment *c;
  57
  58                 while (!list_empty(&iface->ia_assignments)) {
  59                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  60                         free_dhcpv6_assignment(c);
  61                 }
  62         }
  63
  64         if (enable && iface->dhcpv6 == RELAYD_SERVER) {
  65                 if (!iface->ia_assignments.next)
  66                         INIT_LIST_HEAD(&iface->ia_assignments);
  67
  68                 if (list_empty(&iface->ia_assignments)) {
  69                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  70                         if (!border) {
  71                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  72                                 return -1;
  73                         }
  74
  75                         border->length = 64;
  76                         list_add(&border->head, &iface->ia_assignments);
  77                 }
  78
  79                 /* Parse static entries */
  80                 struct lease *lease;
  81                 list_for_each_entry(lease, &leases, head) {
  82                         /* Construct entry */
  83                         size_t duid_len = lease->duid_len ? lease->duid_len : 14;
  84                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + duid_len);
  85                         if (!a) {
  86                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  87                                         iface->ifname);
  88                                 return -1;
  89                         }
  90
  91                         a->leasetime = lease->dhcpv4_leasetime;
  92
  93                         a->clid_len = duid_len;
  94                         a->length = 128;
  95                         if (lease->hostid) {
  96                                 a->assigned = lease->hostid;
  97                         } else {
  98                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  99                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
 100                         }
 101
 102                         odhcpd_urandom(a->key, sizeof(a->key));
 103                         memcpy(a->clid_data, lease->duid, lease->duid_len);
 104                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
 105                         /* Static assignment */
 106                         a->flags |= OAF_STATIC;
 107                         /* Infinite valid */
 108                         a->valid_until = 0;
 109
 110                         /* Assign to all interfaces */
 111                         struct dhcpv6_assignment *c;
 112                         list_for_each_entry(c, &iface->ia_assignments, head) {
 113                                 if (c->length != 128 || c->assigned > a->assigned) {
 114                                         list_add_tail(&a->head, &c->head);
 115                                         break;
 116                                 } else if (c->assigned == a->assigned)
 117                                         /* Already an assignment with that number */
 118                                         break;
 119                         }
 120
 121                         if (a->head.next) {
 122                                 if (lease->hostname[0]) {
 123                                         free(a->hostname);
 124                                         a->hostname = strdup(lease->hostname);
 125                                 }
 126                         } else
 127                                 free_dhcpv6_assignment(a);
 128                 }
 129         }
 130         return 0;
 131 }
 132
 133 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c)
 134 {
 135         if (c->managed_sock.fd.registered) {
 136                 ustream_free(&c->managed_sock.stream);
 137                 close(c->managed_sock.fd.fd);
 138         }
 139
 140         if (c->head.next)
 141                 list_del(&c->head);
 142
 143         free(c->managed);
 144         free(c->hostname);
 145         free(c);
 146 }
 147
 148 static inline bool valid_prefix_length(const struct dhcpv6_assignment *a, const uint8_t prefix_length)
 149 {
 150         return (a->managed_size || a->length > prefix_length);
 151 }
 152
 153 static inline bool valid_addr(const struct odhcpd_ipaddr *addr, time_t now)
 154 {
 155         return (addr->prefix <= 96 && addr->preferred > (uint32_t)now);
 156 }
 157
 158 static size_t elect_addr(const struct odhcpd_ipaddr *addrs, const size_t addrlen)
 159 {
 160         size_t i, m;
 161
 162         for (i = 0, m = 0; i < addrlen; ++i) {
 163                 if (addrs[i].preferred > addrs[m].preferred ||
 164                         (addrs[i].preferred == addrs[m].preferred &&
 165                          memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
 166                         m = i;
 167         }
 168
 169         return m;
 170 }
 171
 172 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 173 {
 174         struct {
 175                 struct dhcpv6_client_header hdr;
 176                 uint16_t srvid_type;
 177                 uint16_t srvid_len;
 178                 uint16_t duid_type;
 179                 uint16_t hardware_type;
 180                 uint8_t mac[6];
 181                 uint16_t msg_type;
 182                 uint16_t msg_len;
 183                 uint8_t msg_id;
 184                 struct dhcpv6_auth_reconfigure auth;
 185                 uint16_t clid_type;
 186                 uint16_t clid_len;
 187                 uint8_t clid_data[128];
 188         } __attribute__((packed)) reconf_msg = {
 189                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 190                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 191                 .srvid_len = htons(10),
 192                 .duid_type = htons(3),
 193                 .hardware_type = htons(1),
 194                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 195                 .msg_len = htons(1),
 196                 .msg_id = DHCPV6_MSG_RENEW,
 197                 .auth = {htons(DHCPV6_OPT_AUTH),
 198                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 199                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 200                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 201                 .clid_len = htons(assign->clid_len),
 202                 .clid_data = {0},
 203         };
 204
 205         odhcpd_get_mac(iface, reconf_msg.mac);
 206         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 207         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 208
 209         md5_ctx_t md5;
 210         uint8_t secretbytes[64];
 211         memset(secretbytes, 0, sizeof(secretbytes));
 212         memcpy(secretbytes, assign->key, sizeof(assign->key));
 213
 214         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 215                 secretbytes[i] ^= 0x36;
 216
 217         md5_begin(&md5);
 218         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 219         md5_hash(iov.iov_base, iov.iov_len, &md5);
 220         md5_end(reconf_msg.auth.key, &md5);
 221
 222         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 223                 secretbytes[i] ^= 0x36;
 224                 secretbytes[i] ^= 0x5c;
 225         }
 226
 227         md5_begin(&md5);
 228         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 229         md5_hash(reconf_msg.auth.key, 16, &md5);
 230         md5_end(reconf_msg.auth.key, &md5);
 231
 232         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 233 }
 234
 235 void dhcpv6_write_statefile(void)
 236 {
 237         md5_ctx_t md5;
 238         md5_begin(&md5);
 239
 240         if (config.dhcp_statefile) {
 241                 time_t now = odhcpd_time(), wall_time = time(NULL);
 242                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 243                 if (fd < 0)
 244                         return;
 245
 246                 lockf(fd, F_LOCK, 0);
 247                 if (ftruncate(fd, 0) < 0) {}
 248
 249                 FILE *fp = fdopen(fd, "w");
 250                 if (!fp) {
 251                         close(fd);
 252                         return;
 253                 }
 254
 255                 struct interface *iface;
 256                 list_for_each_entry(iface, &interfaces, head) {
 257                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 258                                 continue;
 259
 260                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 261                                 struct dhcpv6_assignment *c;
 262                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 263                                         if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
 264                                                 continue;
 265
 266                                         char ipbuf[INET6_ADDRSTRLEN];
 267                                         char leasebuf[512];
 268                                         char duidbuf[264];
 269                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 270
 271                                         /* iface DUID iaid hostname lifetime assigned length [addrs...] */
 272                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
 273                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 274                                                         (c->hostname ? c->hostname : "-"),
 275                                                         (c->valid_until > now ?
 276                                                                 (c->valid_until - now + wall_time) :
 277                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 278                                                         c->assigned, (unsigned)c->length);
 279
 280                                         struct in6_addr addr;
 281                                         struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
 282                                         size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
 283                                         size_t m = elect_addr(addrs, addrlen);
 284
 285                                         for (size_t i = 0; i < addrlen; ++i) {
 286                                                 if (!valid_addr(&addrs[i], now) ||
 287                                                             (!INFINITE_VALID(c->valid_until) && c->valid_until <= now))
 288                                                         continue;
 289
 290                                                 addr = addrs[i].addr;
 291                                                 if (c->length == 128) {
 292                                                         if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs))
 293                                                                 continue;
 294
 295                                                         addr.s6_addr32[3] = htonl(c->assigned);
 296                                                 }
 297                                                 else {
 298                                                         if (!valid_prefix_length(c, addrs[i].prefix))
 299                                                                 continue;
 300
 301                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 302                                                 }
 303
 304                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 305
 306                                                 if (c->length == 128 && c->hostname) {
 307                                                         fputs(ipbuf, fp);
 308
 309                                                         char b[256];
 310                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 311                                                                         iface->search, b, sizeof(b)) > 0)
 312                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 313
 314                                                         fprintf(fp, "\t%s\n", c->hostname);
 315                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 316                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 317                                                 }
 318
 319                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
 320                                                                 (c->managed_size) ? addrs[i].prefix : c->length);
 321                                         }
 322                                         leasebuf[l - 1] = '\n';
 323                                         fwrite(leasebuf, 1, l, fp);
 324                                 }
 325                         }
 326
 327                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 328                                 struct dhcpv4_assignment *c;
 329                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 330                                         if (!(c->flags & OAF_BOUND))
 331                                                 continue;
 332
 333                                         char ipbuf[INET6_ADDRSTRLEN];
 334                                         char leasebuf[512];
 335                                         char duidbuf[16];
 336                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 337
 338                                         /* iface DUID iaid hostname lifetime assigned length [addrs...] */
 339                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
 340                                                         iface->ifname, duidbuf,
 341                                                         (c->hostname ? c->hostname : "-"),
 342                                                         (c->valid_until > now ?
 343                                                                 (c->valid_until - now + wall_time) :
 344                                                                 (INFINITE_VALID(c->valid_until) ? -1 : 0)),
 345                                                         c->addr);
 346
 347                                         struct in_addr addr = {htonl(c->addr)};
 348                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 349
 350                                         if (c->hostname) {
 351                                                 fputs(ipbuf, fp);
 352
 353                                                 char b[256];
 354                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 355                                                                 iface->search, b, sizeof(b)) > 0)
 356                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 357
 358                                                 fprintf(fp, "\t%s\n", c->hostname);
 359                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 360                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 361                                         }
 362
 363                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 364                                         leasebuf[l - 1] = '\n';
 365                                         fwrite(leasebuf, 1, l, fp);
 366                                 }
 367                         }
 368                 }
 369
 370                 fclose(fp);
 371         }
 372
 373         uint8_t newmd5[16];
 374         md5_end(newmd5, &md5);
 375
 376         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 377                 memcpy(statemd5, newmd5, sizeof(statemd5));
 378                 char *argv[2] = {config.dhcp_cb, NULL};
 379                 if (!vfork()) {
 380                         execv(argv[0], argv);
 381                         _exit(128);
 382                 }
 383         }
 384 }
 385
 386
 387 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 388 {
 389         if (a->length > 64 || a->managed_size < 0)
 390                 return;
 391
 392         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 393         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 394
 395         for (size_t i = 0; i < addrlen; ++i) {
 396                 struct in6_addr prefix = addrs[i].addr;
 397                 prefix.s6_addr32[1] |= htonl(a->assigned);
 398                 odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
 399                                 iface, &a->peer.sin6_addr, 1024, add);
 400         }
 401 }
 402
 403 /* More data was received from TCP connection */
 404 static void managed_handle_pd_data(struct ustream *s, _unused int bytes_new)
 405 {
 406         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 407         time_t now = odhcpd_time();
 408         bool first = c->managed_size < 0;
 409
 410         for (;;) {
 411                 int pending;
 412                 char *data = ustream_get_read_buf(s, &pending);
 413                 char *end = memmem(data, pending, "\n\n", 2);
 414
 415                 if (!end)
 416                         break;
 417
 418                 end += 2;
 419                 end[-1] = 0;
 420
 421                 c->managed_size = 0;
 422                 if (c->accept_reconf)
 423                         c->reconf_cnt = 1;
 424
 425                 char *saveptr;
 426                 for (char *line = strtok_r(data, "\n", &saveptr); line; line = strtok_r(NULL, "\n", &saveptr)) {
 427                         c->managed = realloc(c->managed, (c->managed_size + 1) * sizeof(*c->managed));
 428                         struct odhcpd_ipaddr *n = &c->managed[c->managed_size];
 429
 430                         char *saveptr2, *x = strtok_r(line, "/", &saveptr2);
 431                         if (!x || inet_pton(AF_INET6, x, &n->addr) < 1)
 432                                 continue;
 433
 434                         x = strtok_r(NULL, ",", &saveptr2);
 435                         if (sscanf(x, "%hhu", &n->prefix) < 1)
 436                                 continue;
 437
 438                         x = strtok_r(NULL, ",", &saveptr2);
 439                         if (sscanf(x, "%u", &n->preferred) < 1)
 440                                 continue;
 441
 442                         x = strtok_r(NULL, ",", &saveptr2);
 443                         if (sscanf(x, "%u", &n->valid) < 1)
 444                                 continue;
 445
 446                         if (n->preferred > n->valid)
 447                                 continue;
 448
 449                         if (UINT32_MAX - now < n->preferred)
 450                                 n->preferred = UINT32_MAX;
 451                         else
 452                                 n->preferred += now;
 453
 454                         if (UINT32_MAX - now < n->valid)
 455                                 n->valid = UINT32_MAX;
 456                         else
 457                                 n->valid += now;
 458
 459                         n->dprefix = 0;
 460
 461                         ++c->managed_size;
 462                 }
 463
 464                 ustream_consume(s, end - data);
 465         }
 466
 467         if (first && c->managed_size == 0)
 468                 free_dhcpv6_assignment(c);
 469         else if (first && !(c->flags & OAF_STATIC))
 470                 c->valid_until = now + 150;
 471 }
 472
 473
 474 /* TCP transmission has ended, either because of success or timeout or other error */
 475 static void managed_handle_pd_done(struct ustream *s)
 476 {
 477         struct dhcpv6_assignment *c = container_of(s, struct dhcpv6_assignment, managed_sock);
 478
 479         if (!(c->flags & OAF_STATIC))
 480                 c->valid_until = odhcpd_time() + 15;
 481
 482         c->managed_size = 0;
 483
 484         if (c->accept_reconf)
 485                 c->reconf_cnt = 1;
 486 }
 487
 488 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 489 {
 490         struct dhcpv6_assignment *c;
 491
 492         if (iface->dhcpv6_pd_manager[0]) {
 493                 int fd = usock(USOCK_UNIX | USOCK_TCP, iface->dhcpv6_pd_manager, NULL);
 494                 if (fd >= 0) {
 495                         char iaidbuf[298];
 496                         odhcpd_hexlify(iaidbuf, assign->clid_data, assign->clid_len);
 497
 498                         assign->managed_sock.stream.notify_read = managed_handle_pd_data;
 499                         assign->managed_sock.stream.notify_state = managed_handle_pd_done;
 500                         ustream_fd_init(&assign->managed_sock, fd);
 501                         ustream_printf(&assign->managed_sock.stream, "%s,%x\n::/%d,0,0\n\n",
 502                                         iaidbuf, assign->iaid, assign->length);
 503                         ustream_write_pending(&assign->managed_sock.stream);
 504                         assign->managed_size = -1;
 505
 506                         if (!(assign->flags & OAF_STATIC))
 507                                 assign->valid_until = odhcpd_time() + 15;
 508
 509                         list_add(&assign->head, &iface->ia_assignments);
 510
 511                         /* Wait initial period of up to 250ms for immediate assignment */
 512                         struct pollfd pfd = { .fd = fd, .events = POLLIN };
 513                         poll(&pfd, 1, 250);
 514                         managed_handle_pd_data(&assign->managed_sock.stream, 0);
 515
 516                         if (fcntl(fd, F_GETFL) >= 0 && assign->managed_size > 0)
 517                                 return true;
 518                 }
 519
 520                 return false;
 521         } else if (iface->ia_addr_len < 1)
 522                 return false;
 523
 524         /* Try honoring the hint first */
 525         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 526         if (assign->assigned) {
 527                 list_for_each_entry(c, &iface->ia_assignments, head) {
 528                         if (c->length == 128 || c->length == 0)
 529                                 continue;
 530
 531                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 532                                 list_add_tail(&assign->head, &c->head);
 533
 534                                 if (assign->flags & OAF_BOUND)
 535                                         apply_lease(iface, assign, true);
 536
 537                                 return true;
 538                         }
 539
 540                         if (c->assigned != 0)
 541                                 current = (c->assigned + (1 << (64 - c->length)));
 542                 }
 543         }
 544
 545         /* Fallback to a variable assignment */
 546         current = 1;
 547         list_for_each_entry(c, &iface->ia_assignments, head) {
 548                 if (c->length == 128 || c->length == 0)
 549                         continue;
 550
 551                 current = (current + asize) & (~asize);
 552                 if (current + asize < c->assigned) {
 553                         assign->assigned = current;
 554                         list_add_tail(&assign->head, &c->head);
 555
 556                         if (assign->flags & OAF_BOUND)
 557                                 apply_lease(iface, assign, true);
 558
 559                         return true;
 560                 }
 561
 562                 if (c->assigned != 0)
 563                         current = (c->assigned + (1 << (64 - c->length)));
 564         }
 565
 566         return false;
 567 }
 568
 569 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 570 {
 571         /* Seed RNG with checksum of DUID */
 572         uint32_t seed = 0;
 573         for (size_t i = 0; i < assign->clid_len; ++i)
 574                 seed += assign->clid_data[i];
 575         srand(seed);
 576
 577         /* Try to assign up to 100x */
 578         for (size_t i = 0; i < 100; ++i) {
 579                 uint32_t try;
 580                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 581
 582                 struct dhcpv6_assignment *c;
 583                 list_for_each_entry(c, &iface->ia_assignments, head) {
 584                         if (c->length == 0)
 585                                 continue;
 586
 587                         if (c->assigned > try || c->length != 128) {
 588                                 assign->assigned = try;
 589                                 list_add_tail(&assign->head, &c->head);
 590                                 return true;
 591                         } else if (c->assigned == try)
 592                                 break;
 593                 }
 594         }
 595
 596         return false;
 597 }
 598
 599 void dhcpv6_ia_preupdate(struct interface *iface)
 600 {
 601         if (iface->dhcpv6 != RELAYD_SERVER)
 602                 return;
 603
 604         struct dhcpv6_assignment *c, *border = list_last_entry(
 605                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 606
 607         list_for_each_entry(c, &iface->ia_assignments, head)
 608                 if (c != border && !iface->managed && (c->flags & OAF_BOUND))
 609                         apply_lease(iface, c, false);
 610 }
 611
 612 void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
 613 {
 614         if (iface->dhcpv6 != RELAYD_SERVER)
 615                 return;
 616
 617         int minprefix = -1;
 618         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 619                 if (iface->ia_addr[i].preferred > (uint32_t)now &&
 620                                 iface->ia_addr[i].prefix < 64 &&
 621                                 iface->ia_addr[i].prefix > minprefix)
 622                         minprefix = iface->ia_addr[i].prefix;
 623         }
 624
 625         struct dhcpv6_assignment *border = list_last_entry(
 626                         &iface->ia_assignments, struct dhcpv6_assignment, head);
 627
 628         if (minprefix > 32 && minprefix <= 64)
 629                 border->assigned = 1U << (64 - minprefix);
 630         else
 631                 border->assigned = 0;
 632
 633         struct list_head reassign = LIST_HEAD_INIT(reassign);
 634         struct dhcpv6_assignment *c, *d;
 635         list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 636                 if (c->clid_len == 0 || (!INFINITE_VALID(c->valid_until) && c->valid_until < now) ||
 637                                 c->managed_size)
 638                         continue;
 639
 640                 if (c->length < 128 && c->assigned >= border->assigned && c != border)
 641                         list_move(&c->head, &reassign);
 642                 else if (c != border && (c->flags & OAF_BOUND))
 643                         apply_lease(iface, c, true);
 644
 645                 if (c->accept_reconf && c->reconf_cnt == 0) {
 646                         c->reconf_cnt = 1;
 647                         c->reconf_sent = now;
 648                         send_reconf(iface, c);
 649
 650                         /* Leave all other assignments of that client alone */
 651                         struct dhcpv6_assignment *a;
 652                         list_for_each_entry(a, &iface->ia_assignments, head)
 653                                 if (a != c && a->clid_len == c->clid_len &&
 654                                                 !memcmp(a->clid_data, c->clid_data, a->clid_len))
 655                                         c->reconf_cnt = INT_MAX;
 656                 }
 657         }
 658
 659         while (!list_empty(&reassign)) {
 660                 c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 661                 list_del(&c->head);
 662                 if (!assign_pd(iface, c)) {
 663                         c->assigned = 0;
 664                         list_add(&c->head, &iface->ia_assignments);
 665                 }
 666         }
 667
 668         dhcpv6_write_statefile();
 669 }
 670
 671 static void reconf_timer(struct uloop_timeout *event)
 672 {
 673         time_t now = odhcpd_time();
 674         struct interface *iface;
 675         list_for_each_entry(iface, &interfaces, head) {
 676                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 677                         continue;
 678
 679                 struct dhcpv6_assignment *a, *n;
 680                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 681                         if (!INFINITE_VALID(a->valid_until) && a->valid_until < now) {
 682                                 if ((a->length < 128 && a->clid_len > 0) ||
 683                                                 (a->length == 128 && a->clid_len == 0))
 684                                         free_dhcpv6_assignment(a);
 685
 686                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 687                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 688                                 ++a->reconf_cnt;
 689                                 a->reconf_sent = now;
 690                                 send_reconf(iface, a);
 691                         }
 692                 }
 693         }
 694         uloop_timeout_set(event, 2000);
 695 }
 696
 697 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 698                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 699                 struct interface *iface, bool request)
 700 {
 701         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 702                 return 0;
 703
 704         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 705         size_t datalen = sizeof(out);
 706         time_t now = odhcpd_time();
 707
 708         if (status) {
 709                 struct __attribute__((packed)) {
 710                         uint16_t type;
 711                         uint16_t len;
 712                         uint16_t value;
 713                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 714                                 htons(status)};
 715
 716                 memcpy(buf + datalen, &stat, sizeof(stat));
 717                 datalen += sizeof(stat);
 718         } else {
 719                 if (a) {
 720                         uint32_t leasetime;
 721                         if (a->leasetime)
 722                                 leasetime = a->leasetime;
 723                         else
 724                                 leasetime = iface->dhcpv4_leasetime;
 725
 726                         uint32_t pref = leasetime;
 727                         uint32_t valid = leasetime;
 728
 729                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 730                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 731                         size_t m = elect_addr(addrs, addrlen);
 732
 733                         for (size_t i = 0; i < addrlen; ++i) {
 734                                 uint32_t prefix_pref = addrs[i].preferred;
 735                                 uint32_t prefix_valid = addrs[i].valid;
 736
 737                                 if (!valid_addr(&addrs[i], now))
 738                                         continue;
 739
 740                                 if (prefix_pref != UINT32_MAX)
 741                                         prefix_pref -= now;
 742
 743                                 if (prefix_valid != UINT32_MAX)
 744                                         prefix_valid -= now;
 745
 746                                 if (a->length < 128) {
 747                                         struct dhcpv6_ia_prefix p = {
 748                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 749                                                 .len = htons(sizeof(p) - 4),
 750                                                 .preferred = htonl(prefix_pref),
 751                                                 .valid = htonl(prefix_valid),
 752                                                 .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
 753                                                 .addr = addrs[i].addr
 754                                         };
 755                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 756
 757                                         size_t entrlen = sizeof(p) - 4;
 758
 759                                         if (datalen + entrlen + 4 > buflen ||
 760                                                         (a->assigned == 0 && a->managed_size == 0) ||
 761                                                         !valid_prefix_length(a, addrs[i].prefix))
 762                                                 continue;
 763
 764                                         memcpy(buf + datalen, &p, sizeof(p));
 765                                         datalen += entrlen + 4;
 766                                 } else {
 767                                         struct dhcpv6_ia_addr n = {
 768                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 769                                                 .len = htons(sizeof(n) - 4),
 770                                                 .addr = addrs[i].addr,
 771                                                 .preferred = htonl(prefix_pref),
 772                                                 .valid = htonl(prefix_valid)
 773                                         };
 774                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 775                                         size_t entrlen = sizeof(n) - 4;
 776
 777                                         if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
 778                                                         a->assigned == 0 ||
 779                                                         datalen + entrlen + 4 > buflen)
 780                                                 continue;
 781
 782                                         memcpy(buf + datalen, &n, sizeof(n));
 783                                         datalen += entrlen + 4;
 784                                 }
 785
 786                                 /* Calculate T1 / T2 based on non-deprecated addresses */
 787                                 if (prefix_pref > 0) {
 788                                         if (prefix_pref < pref)
 789                                                 pref = prefix_pref;
 790
 791                                         if (prefix_valid < valid)
 792                                                 valid = prefix_valid;
 793                                 }
 794                         }
 795
 796                         if (!INFINITE_VALID(a->valid_until))
 797                                 /* UINT32_MAX is considered as infinite leasetime */
 798                                 a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 799
 800                         out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
 801                         out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 802
 803                         if (!out.t1)
 804                                 out.t1 = htonl(1);
 805
 806                         if (!out.t2)
 807                                 out.t2 = htonl(1);
 808                 }
 809
 810                 if (!request) {
 811                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 812                         uint16_t otype, olen;
 813                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 814                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 815                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 816                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 817                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 818                                         continue;
 819
 820                                 bool found = false;
 821                                 if (a) {
 822                                         struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 823                                         size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 824
 825                                         for (size_t i = 0; i < addrlen; ++i) {
 826                                                 if (!valid_addr(&addrs[i], now))
 827                                                         continue;
 828
 829                                                 struct in6_addr addr = addrs[i].addr;
 830                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 831                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 832
 833                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 834                                                                         p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
 835                                                                 found = true;
 836                                                 } else {
 837                                                         addr.s6_addr32[3] = htonl(a->assigned);
 838
 839                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 840                                                                 found = true;
 841                                                 }
 842                                         }
 843                                 }
 844
 845                                 if (!found) {
 846                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 847                                                 struct dhcpv6_ia_prefix inv = {
 848                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 849                                                         .len = htons(sizeof(inv) - 4),
 850                                                         .preferred = 0,
 851                                                         .valid = 0,
 852                                                         .prefix = p->prefix,
 853                                                         .addr = p->addr
 854                                                 };
 855
 856                                                 if (datalen + sizeof(inv) > buflen)
 857                                                         continue;
 858
 859                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 860                                                 datalen += sizeof(inv);
 861                                         } else {
 862                                                 struct dhcpv6_ia_addr inv = {
 863                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 864                                                         .len = htons(sizeof(inv) - 4),
 865                                                         .addr = n->addr,
 866                                                         .preferred = 0,
 867                                                         .valid = 0
 868                                                 };
 869
 870                                                 if (datalen + sizeof(inv) > buflen)
 871                                                         continue;
 872
 873                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 874                                                 datalen += sizeof(inv);
 875                                         }
 876                                 }
 877                         }
 878                 }
 879         }
 880
 881         out.len = htons(datalen - 4);
 882         memcpy(buf, &out, sizeof(out));
 883         return datalen;
 884 }
 885
 886 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 887                 const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 888 {
 889         const char *type = "UNKNOWN";
 890         const char *status = "UNKNOWN";
 891
 892         if (msgtype == DHCPV6_MSG_RENEW)
 893                 return;
 894
 895         switch (msgtype) {
 896         case DHCPV6_MSG_SOLICIT:
 897                 type = "SOLICIT";
 898                 break;
 899         case DHCPV6_MSG_REQUEST:
 900                 type = "REQUEST";
 901                 break;
 902         case DHCPV6_MSG_CONFIRM:
 903                 type = "CONFIRM";
 904                 break;
 905         case DHCPV6_MSG_RENEW:
 906                 type = "RENEW";
 907                 break;
 908         case DHCPV6_MSG_REBIND:
 909                 type = "REBIND";
 910                 break;
 911         case DHCPV6_MSG_RELEASE:
 912                 type = "RELEASE";
 913                 break;
 914         case DHCPV6_MSG_DECLINE:
 915                 type = "DECLINE";
 916                 break;
 917         }
 918
 919         switch (code) {
 920         case DHCPV6_STATUS_OK:
 921                 status = "ok";
 922                 break;
 923         case DHCPV6_STATUS_NOADDRSAVAIL:
 924                 status = "no addresses available";
 925                 break;
 926         case DHCPV6_STATUS_NOBINDING:
 927                 status = "no binding";
 928                 break;
 929         case DHCPV6_STATUS_NOTONLINK:
 930                 status = "not on-link";
 931                 break;
 932         case DHCPV6_STATUS_NOPREFIXAVAIL:
 933                 status = "no prefix available";
 934                 break;
 935         }
 936
 937         char leasebuf[256] = "";
 938
 939         if (a) {
 940                 struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
 941                 size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 942                 size_t lbsize = 0;
 943                 size_t m = elect_addr(addrs, addrlen);
 944                 char addrbuf[INET6_ADDRSTRLEN];
 945
 946                 for (size_t i = 0; i < addrlen; ++i) {
 947                         if (!valid_addr(&addrs[i], now))
 948                                 continue;
 949
 950                         struct in6_addr addr = addrs[i].addr;
 951                         int prefix = a->managed ? addrs[i].prefix : a->length;
 952                         if (prefix == 128) {
 953                                 if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
 954                                                 a->assigned == 0)
 955                                         continue;
 956
 957                                 addr.s6_addr32[3] = htonl(a->assigned);
 958                         }
 959                         else {
 960                                 if (!valid_prefix_length(a, addrs[i].prefix))
 961                                         continue;
 962
 963                                 addr.s6_addr32[1] |= htonl(a->assigned);
 964                         }
 965
 966                         inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
 967                         lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
 968                 }
 969         }
 970
 971         syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
 972                         duidbuf, iface->ifname, status, leasebuf);
 973 }
 974
 975 ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 976                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 977 {
 978         time_t now = odhcpd_time();
 979         size_t response_len = 0;
 980         const struct dhcpv6_client_header *hdr = data;
 981         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 982         uint16_t otype, olen;
 983         /* Find and parse client-id and hostname */
 984         bool accept_reconf = false;
 985         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 986         char hostname[256];
 987         size_t hostname_len = 0;
 988         bool notonlink = false;
 989         char duidbuf[261];
 990
 991         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 992                 if (otype == DHCPV6_OPT_CLIENTID) {
 993                         clid_data = odata;
 994                         clid_len = olen;
 995
 996                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 997                                 memcpy(mac, &odata[8], sizeof(mac));
 998                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 999                                 memcpy(mac, &odata[4], sizeof(mac));
1000
1001                         if (olen <= 130)
1002                                 odhcpd_hexlify(duidbuf, odata, olen);
1003                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
1004                         uint8_t fqdn_buf[256];
1005                         memcpy(fqdn_buf, odata, olen);
1006                         fqdn_buf[olen++] = 0;
1007
1008                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
1009                                 hostname_len = strcspn(hostname, ".");
1010                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT)
1011                         accept_reconf = true;
1012         }
1013
1014         if (!clid_data || !clid_len || clid_len > 130)
1015                 goto out;
1016
1017         struct dhcpv6_assignment *first = NULL;
1018         dhcpv6_for_each_option(start, end, otype, olen, odata) {
1019                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
1020                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
1021                 bool ia_addr_present = false;
1022                 if (!is_pd && !is_na)
1023                         continue;
1024
1025                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
1026                 size_t ia_response_len = 0;
1027                 uint8_t reqlen = (is_pd) ? 62 : 128;
1028                 uint32_t reqhint = 0;
1029
1030                 /* Parse request hint for IA-PD */
1031                 if (is_pd) {
1032                         uint8_t *sdata;
1033                         uint16_t stype, slen;
1034                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1035                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
1036                                         continue;
1037
1038                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
1039                                 if (p->prefix) {
1040                                         reqlen = p->prefix;
1041                                         reqhint = ntohl(p->addr.s6_addr32[1]);
1042                                         if (reqlen > 32 && reqlen <= 64)
1043                                                 reqhint &= (1U << (64 - reqlen)) - 1;
1044                                 }
1045                         }
1046
1047                         if (reqlen > 64)
1048                                 reqlen = 64;
1049                 } else if (is_na) {
1050                         uint8_t *sdata;
1051                         uint16_t stype, slen;
1052                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
1053                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
1054                                         continue;
1055
1056                                 ia_addr_present = true;
1057                         }
1058                 }
1059
1060                 /* Find assignment */
1061                 struct dhcpv6_assignment *c, *a = NULL;
1062                 list_for_each_entry(c, &iface->ia_assignments, head) {
1063                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
1064                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
1065                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
1066                                         (c->iaid == ia->iaid || INFINITE_VALID(c->valid_until) || now < c->valid_until) &&
1067                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
1068                                 a = c;
1069
1070                                 /* Reset state */
1071                                 if (a->flags & OAF_BOUND)
1072                                         apply_lease(iface, a, false);
1073
1074                                 memcpy(a->clid_data, clid_data, clid_len);
1075                                 a->clid_len = clid_len;
1076                                 a->iaid = ia->iaid;
1077                                 a->peer = *addr;
1078                                 a->reconf_cnt = 0;
1079                                 a->reconf_sent = 0;
1080                                 break;
1081                         }
1082                 }
1083
1084                 /* Generic message handling */
1085                 uint16_t status = DHCPV6_STATUS_OK;
1086                 if (a && a->managed_size < 0)
1087                         return -1;
1088
1089                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
1090                         bool assigned = !!a;
1091
1092                         if (!a && !iface->no_dynamic_dhcp) {
1093                                 /* Create new binding */
1094                                 a = calloc(1, sizeof(*a) + clid_len);
1095                                 if (a) {
1096                                         a->clid_len = clid_len;
1097                                         a->iaid = ia->iaid;
1098                                         a->length = reqlen;
1099                                         a->peer = *addr;
1100                                         a->assigned = reqhint;
1101                                         /* Set valid time to current time indicating  */
1102                                         /* assignment is not having infinite lifetime */
1103                                         a->valid_until = now;
1104
1105                                         if (first)
1106                                                 memcpy(a->key, first->key, sizeof(a->key));
1107                                         else
1108                                                 odhcpd_urandom(a->key, sizeof(a->key));
1109                                         memcpy(a->clid_data, clid_data, clid_len);
1110
1111                                         if (is_pd)
1112                                                 while (!(assigned = assign_pd(iface, a)) &&
1113                                                                 !a->managed_size && ++a->length <= 64);
1114                                         else
1115                                                 assigned = assign_na(iface, a);
1116
1117                                         if (a->managed_size && !assigned)
1118                                                 return -1;
1119                                 }
1120                         }
1121
1122                         if (!assigned || iface->ia_addr_len == 0)
1123                                 /* Set error status */
1124                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
1125                         else if (assigned && !first) {
1126                                 size_t handshake_len = 4;
1127                                 buf[0] = 0;
1128                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
1129                                 buf[2] = 0;
1130                                 buf[3] = 0;
1131
1132                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
1133                                         struct dhcpv6_auth_reconfigure auth = {
1134                                                 htons(DHCPV6_OPT_AUTH),
1135                                                 htons(sizeof(auth) - 4),
1136                                                 3, 1, 0,
1137                                                 {htonl(time(NULL)), htonl(++serial)},
1138                                                 1,
1139                                                 {0}
1140                                         };
1141                                         memcpy(auth.key, a->key, sizeof(a->key));
1142                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
1143                                         handshake_len += sizeof(auth);
1144                                 }
1145
1146                                 buf += handshake_len;
1147                                 buflen -= handshake_len;
1148                                 response_len += handshake_len;
1149
1150                                 first = a;
1151                         }
1152
1153                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1154
1155                         /* Was only a solicitation: mark binding for removal */
1156                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
1157                                 a->flags &= ~OAF_BOUND;
1158
1159                                 if (!(a->flags & OAF_STATIC))
1160                                         a->valid_until = now;
1161                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
1162                                 if (hostname_len > 0) {
1163                                         a->hostname = realloc(a->hostname, hostname_len + 1);
1164                                         if (a->hostname) {
1165                                                 memcpy(a->hostname, hostname, hostname_len);
1166                                                 a->hostname[hostname_len] = 0;
1167                                         }
1168                                 }
1169                                 a->accept_reconf = accept_reconf;
1170                                 a->flags |= OAF_BOUND;
1171                                 apply_lease(iface, a, true);
1172                         } else if (!assigned && a && a->managed_size == 0) {
1173                                 /* Cleanup failed assignment */
1174                                 free_dhcpv6_assignment(a);
1175                                 a = NULL;
1176                         }
1177                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1178                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1179                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1180                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1181                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1182                                 status = DHCPV6_STATUS_NOBINDING;
1183                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1184                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1185                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1186                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1187                                 if (a) {
1188                                         a->flags |= OAF_BOUND;
1189                                         apply_lease(iface, a, true);
1190                                 }
1191                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1192                                 if (!(a->flags & OAF_STATIC))
1193                                         a->valid_until = now - 1;
1194
1195                                 if (a->flags & OAF_BOUND) {
1196                                         apply_lease(iface, a, false);
1197                                         a->flags &= ~OAF_BOUND;
1198                                 }
1199                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1200                                 a->flags &= ~OAF_BOUND;
1201
1202                                 if (!(a->flags & OAF_STATIC)) {
1203                                         a->clid_len = 0;
1204                                         a->valid_until = now + 3600; /* Block address for 1h */
1205                                 }
1206                         }
1207                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
1208                         /* Send NOTONLINK for CONFIRM with addr present so that clients restart connection */
1209                         status = DHCPV6_STATUS_NOTONLINK;
1210                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1211                         notonlink = true;
1212                 }
1213
1214                 buf += ia_response_len;
1215                 buflen -= ia_response_len;
1216                 response_len += ia_response_len;
1217                 dhcpv6_log(hdr->msg_type, iface, now, duidbuf, is_pd, a, status);
1218         }
1219
1220         if ((hdr->msg_type == DHCPV6_MSG_RELEASE || hdr->msg_type == DHCPV6_MSG_DECLINE || notonlink) &&
1221                         response_len + 6 < buflen) {
1222                 buf[0] = 0;
1223                 buf[1] = DHCPV6_OPT_STATUS;
1224                 buf[2] = 0;
1225                 buf[3] = 2;
1226                 buf[4] = 0;
1227                 buf[5] = (notonlink) ? DHCPV6_STATUS_NOTONLINK : DHCPV6_STATUS_OK;
1228                 response_len += 6;
1229         }
1230
1231         dhcpv6_write_statefile();
1232
1233 out:
1234         return response_len;
1235 }