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
  20 #include <time.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <alloca.h>
  24 #include <resolv.h>
  25 #include <limits.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <arpa/inet.h>
  29 #include <sys/timerfd.h>
  30
  31
  32 static void update(struct interface *iface);
  33 static void reconf_timer(struct uloop_timeout *event);
  34 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  35 static int socket_fd = -1;
  36 static uint32_t serial = 0;
  37
  38
  39 int dhcpv6_ia_init(int dhcpv6_socket)
  40 {
  41         socket_fd = dhcpv6_socket;
  42         uloop_timeout_set(&reconf_event, 2000);
  43         return 0;
  44 }
  45
  46
  47 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  48 {
  49         if (!enable && iface->ia_assignments.next) {
  50                 struct dhcpv6_assignment *c;
  51                 while (!list_empty(&iface->ia_assignments)) {
  52                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  53                         list_del(&c->head);
  54                         free(c->hostname);
  55                         free(c->classes);
  56                         free(c);
  57                 }
  58         }
  59
  60         if (iface->dhcpv6 == RELAYD_SERVER) {
  61                 if (!iface->ia_assignments.next)
  62                         INIT_LIST_HEAD(&iface->ia_assignments);
  63
  64                 if (list_empty(&iface->ia_assignments)) {
  65                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  66                         if (!border) {
  67                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  68                                 return -1;
  69                         }
  70
  71                         border->length = 64;
  72                         list_add(&border->head, &iface->ia_assignments);
  73                 }
  74
  75                 update(iface);
  76
  77                 // Parse static entries
  78                 struct lease *lease;
  79                 list_for_each_entry(lease, &leases, head) {
  80                         // Construct entry
  81                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  82                         if (!a) {
  83                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  84                                         iface->ifname);
  85                                 return -1;
  86                         }
  87
  88                         a->clid_len = lease->duid_len;
  89                         a->length = 128;
  90                         if (lease->hostid) {
  91                                 a->assigned = lease->hostid;
  92                         } else {
  93                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  94                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
  95                         }
  96                         odhcpd_urandom(a->key, sizeof(a->key));
  97                         memcpy(a->clid_data, lease->duid, a->clid_len);
  98                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
  99
 100                         // Assign to all interfaces
 101                         struct dhcpv6_assignment *c;
 102                         list_for_each_entry(c, &iface->ia_assignments, head) {
 103                                 if (c->length != 128 || c->assigned > a->assigned) {
 104                                         list_add_tail(&a->head, &c->head);
 105                                 } else if (c->assigned == a->assigned) {
 106                                         // Already an assignment with that number
 107                                         break;
 108                                 }
 109                         }
 110
 111                         if (a->head.next) {
 112                                 if (lease->hostname[0]) {
 113                                         free(a->hostname);
 114                                         a->hostname = strdup(lease->hostname);
 115                                 }
 116                         } else {
 117                                 free(a->classes);
 118                                 free(a->hostname);
 119                                 free(a);
 120                         }
 121                 }
 122         }
 123         return 0;
 124 }
 125
 126
 127 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 128 {
 129         struct {
 130                 struct dhcpv6_client_header hdr;
 131                 uint16_t srvid_type;
 132                 uint16_t srvid_len;
 133                 uint16_t duid_type;
 134                 uint16_t hardware_type;
 135                 uint8_t mac[6];
 136                 uint16_t msg_type;
 137                 uint16_t msg_len;
 138                 uint8_t msg_id;
 139                 struct dhcpv6_auth_reconfigure auth;
 140                 uint16_t clid_type;
 141                 uint16_t clid_len;
 142                 uint8_t clid_data[128];
 143         } __attribute__((packed)) reconf_msg = {
 144                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 145                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 146                 .srvid_len = htons(10),
 147                 .duid_type = htons(3),
 148                 .hardware_type = htons(1),
 149                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 150                 .msg_len = htons(1),
 151                 .msg_id = DHCPV6_MSG_RENEW,
 152                 .auth = {htons(DHCPV6_OPT_AUTH),
 153                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 154                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 155                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 156                 .clid_len = htons(assign->clid_len),
 157                 .clid_data = {0},
 158         };
 159
 160         odhcpd_get_mac(iface, reconf_msg.mac);
 161         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 162         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 163
 164         md5_ctx_t md5;
 165         uint8_t secretbytes[16];
 166         memcpy(secretbytes, assign->key, sizeof(secretbytes));
 167
 168         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 169                 secretbytes[i] ^= 0x36;
 170
 171         md5_begin(&md5);
 172         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 173         md5_hash(iov.iov_base, iov.iov_len, &md5);
 174         md5_end(reconf_msg.auth.key, &md5);
 175
 176         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 177                 secretbytes[i] ^= 0x36;
 178                 secretbytes[i] ^= 0x5c;
 179         }
 180
 181         md5_begin(&md5);
 182         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 183         md5_hash(reconf_msg.auth.key, 16, &md5);
 184         md5_end(reconf_msg.auth.key, &md5);
 185
 186         return odhcpd_send(socket_fd, &assign->peer, &iov, 1, iface);
 187 }
 188
 189
 190 void dhcpv6_write_statefile(void)
 191 {
 192         if (config.dhcp_statefile) {
 193                 time_t now = odhcpd_time(), wall_time = time(NULL);
 194                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 195                 if (fd < 0)
 196                         return;
 197
 198                 lockf(fd, F_LOCK, 0);
 199                 ftruncate(fd, 0);
 200
 201                 FILE *fp = fdopen(fd, "w");
 202                 if (!fp) {
 203                         close(fd);
 204                         return;
 205                 }
 206
 207                 struct interface *iface;
 208                 list_for_each_entry(iface, &interfaces, head) {
 209                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 210                                 continue;
 211
 212                         if (iface->dhcpv6 == RELAYD_SERVER) {
 213                                 struct dhcpv6_assignment *c;
 214                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 215                                         if (c->clid_len == 0)
 216                                                 continue;
 217
 218                                         char ipbuf[INET6_ADDRSTRLEN];
 219                                         char leasebuf[512];
 220                                         char duidbuf[264];
 221                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 222
 223                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 224                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 225                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 226                                                         (c->hostname ? c->hostname : "-"),
 227                                                         (unsigned)(c->valid_until > now ?
 228                                                                         (c->valid_until - now + wall_time) : 0),
 229                                                         c->assigned, (unsigned)c->length);
 230
 231                                         struct in6_addr addr;
 232                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 233                                                 if (iface->ia_addr[i].prefix > 64)
 234                                                         continue;
 235
 236                                                 addr = iface->ia_addr[i].addr;
 237                                                 if (c->length == 128)
 238                                                         addr.s6_addr32[3] = htonl(c->assigned);
 239                                                 else
 240                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 241                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 242
 243                                                 if (c->length == 128 && c->hostname && i == 0)
 244                                                         fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
 245
 246                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length);
 247                                         }
 248                                         leasebuf[l - 1] = '\n';
 249                                         fwrite(leasebuf, 1, l, fp);
 250                                 }
 251                         }
 252
 253                         if (iface->dhcpv4 == RELAYD_SERVER) {
 254                                 struct dhcpv4_assignment *c;
 255                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 256                                         char ipbuf[INET6_ADDRSTRLEN];
 257                                         char leasebuf[512];
 258                                         char duidbuf[16];
 259                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 260
 261                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 262                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 263                                                         iface->ifname, duidbuf,
 264                                                         (c->hostname ? c->hostname : "-"),
 265                                                         (unsigned)(c->valid_until > now ?
 266                                                                         (c->valid_until - now + wall_time) : 0),
 267                                                         c->addr);
 268
 269                                         struct in_addr addr = {htonl(c->addr)};
 270                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 271
 272                                         if (c->hostname[0])
 273                                                 fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
 274
 275                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 276                                         leasebuf[l - 1] = '\n';
 277                                         fwrite(leasebuf, 1, l, fp);
 278                                 }
 279                         }
 280                 }
 281
 282                 fclose(fp);
 283         }
 284
 285         if (config.dhcp_cb) {
 286                 char *argv[2] = {config.dhcp_cb, NULL};
 287                 if (!vfork()) {
 288                         execv(argv[0], argv);
 289                         _exit(128);
 290                 }
 291         }
 292 }
 293
 294
 295 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 296 {
 297         if (a->length > 64)
 298                 return;
 299
 300         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 301                 struct in6_addr prefix = iface->ia_addr[i].addr;
 302                 prefix.s6_addr32[1] |= htonl(a->assigned);
 303                 odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add);
 304         }
 305 }
 306
 307
 308 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 309 {
 310         struct dhcpv6_assignment *c;
 311         if (iface->ia_addr_len < 1)
 312                 return false;
 313
 314         // Try honoring the hint first
 315         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 316         if (assign->assigned) {
 317                 list_for_each_entry(c, &iface->ia_assignments, head) {
 318                         if (c->length == 128)
 319                                 continue;
 320
 321                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 322                                 list_add_tail(&assign->head, &c->head);
 323                                 apply_lease(iface, assign, true);
 324                                 return true;
 325                         }
 326
 327                         if (c->assigned != 0)
 328                                 current = (c->assigned + (1 << (64 - c->length)));
 329                 }
 330         }
 331
 332         // Fallback to a variable assignment
 333         current = 1;
 334         list_for_each_entry(c, &iface->ia_assignments, head) {
 335                 if (c->length == 128)
 336                         continue;
 337
 338                 current = (current + asize) & (~asize);
 339                 if (current + asize < c->assigned) {
 340                         assign->assigned = current;
 341                         list_add_tail(&assign->head, &c->head);
 342                         apply_lease(iface, assign, true);
 343                         return true;
 344                 }
 345
 346                 if (c->assigned != 0)
 347                         current = (c->assigned + (1 << (64 - c->length)));
 348         }
 349
 350         return false;
 351 }
 352
 353
 354 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 355 {
 356         bool match = false;
 357         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 358                 if (!iface->ia_addr[i].has_class) {
 359                         match = true;
 360                         continue;
 361                 } else if (assign->classes_cnt) {
 362                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 363                                 if (assign->classes[j] == iface->ia_addr[i].class)
 364                                         match = true;
 365                 } else if (assign->all_class) {
 366                         match = true;
 367                 }
 368         }
 369
 370         if (!match)
 371                 return false;
 372
 373         // Seed RNG with checksum of DUID
 374         uint32_t seed = 0;
 375         for (size_t i = 0; i < assign->clid_len; ++i)
 376                 seed += assign->clid_data[i];
 377         srand(seed);
 378
 379         // Try to assign up to 100x
 380         for (size_t i = 0; i < 100; ++i) {
 381                 uint32_t try;
 382                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 383
 384                 struct dhcpv6_assignment *c;
 385                 list_for_each_entry(c, &iface->ia_assignments, head) {
 386                         if (c->assigned > try || c->length != 128) {
 387                                 assign->assigned = try;
 388                                 list_add_tail(&assign->head, &c->head);
 389                                 return true;
 390                         } else if (c->assigned == try) {
 391                                 break;
 392                         }
 393                 }
 394         }
 395
 396         return false;
 397 }
 398
 399
 400 static int prefixcmp(const void *va, const void *vb)
 401 {
 402         const struct odhcpd_ipaddr *a = va, *b = vb;
 403         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 404         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 405         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 406 }
 407
 408
 409 static void update(struct interface *iface)
 410 {
 411         struct odhcpd_ipaddr addr[8];
 412         memset(addr, 0, sizeof(addr));
 413         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 414
 415         if (len < 0)
 416                 return;
 417
 418         qsort(addr, len, sizeof(*addr), prefixcmp);
 419
 420         time_t now = odhcpd_time();
 421         int minprefix = -1;
 422
 423         for (int i = 0; i < len; ++i) {
 424                 if (addr[i].prefix > minprefix)
 425                         minprefix = addr[i].prefix;
 426
 427                 addr[i].addr.s6_addr32[2] = 0;
 428                 addr[i].addr.s6_addr32[3] = 0;
 429
 430                 if (addr[i].preferred < UINT32_MAX - now)
 431                         addr[i].preferred += now;
 432
 433                 if (addr[i].valid < UINT32_MAX - now)
 434                         addr[i].valid += now;
 435         }
 436
 437         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 438         border->assigned = 1 << (64 - minprefix);
 439
 440         bool change = len != (int)iface->ia_addr_len;
 441         for (int i = 0; !change && i < len; ++i)
 442                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 443                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 444                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 445                                 (addr[i].valid > (uint32_t)now + 7200) !=
 446                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 447                         change = true;
 448
 449         if (change) {
 450                 struct dhcpv6_assignment *c;
 451                 list_for_each_entry(c, &iface->ia_assignments, head)
 452                         if (c != border)
 453                                 apply_lease(iface, c, false);
 454         }
 455
 456         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 457         iface->ia_addr_len = len;
 458
 459         if (change) { // Addresses / prefixes have changed
 460                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 461                 struct dhcpv6_assignment *c, *d;
 462                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 463                         if (c->clid_len == 0 || c->valid_until < now)
 464                                 continue;
 465
 466                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 467                                 list_move(&c->head, &reassign);
 468                         else if (c != border)
 469                                 apply_lease(iface, c, true);
 470
 471                         if (c->accept_reconf && c->reconf_cnt == 0) {
 472                                 c->reconf_cnt = 1;
 473                                 c->reconf_sent = now;
 474                                 send_reconf(iface, c);
 475
 476                                 // Leave all other assignments of that client alone
 477                                 struct dhcpv6_assignment *a;
 478                                 list_for_each_entry(a, &iface->ia_assignments, head)
 479                                         if (a != c && a->clid_len == c->clid_len &&
 480                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 481                                                 c->reconf_cnt = INT_MAX;
 482                         }
 483                 }
 484
 485                 while (!list_empty(&reassign)) {
 486                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 487                         list_del(&c->head);
 488                         if (!assign_pd(iface, c)) {
 489                                 c->assigned = 0;
 490                                 list_add(&c->head, &iface->ia_assignments);
 491                         }
 492                 }
 493
 494                 dhcpv6_write_statefile();
 495         }
 496 }
 497
 498
 499 static void reconf_timer(struct uloop_timeout *event)
 500 {
 501         time_t now = odhcpd_time();
 502         struct interface *iface;
 503         list_for_each_entry(iface, &interfaces, head) {
 504                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 505                         continue;
 506
 507                 struct dhcpv6_assignment *a, *n;
 508                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 509                         if (a->valid_until < now) {
 510                                 if ((a->length < 128 && a->clid_len > 0) ||
 511                                                 (a->length == 128 && a->clid_len == 0)) {
 512                                         list_del(&a->head);
 513                                         free(a->classes);
 514                                         free(a->hostname);
 515                                         free(a);
 516                                 }
 517                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 518                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 519                                 ++a->reconf_cnt;
 520                                 a->reconf_sent = now;
 521                                 send_reconf(iface, a);
 522                         }
 523                 }
 524
 525                 if (iface->ia_reconf) {
 526                         update(iface);
 527                         iface->ia_reconf = false;
 528                 }
 529         }
 530
 531         uloop_timeout_set(event, 2000);
 532 }
 533
 534
 535 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 536                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 537                 struct interface *iface, bool request)
 538 {
 539         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 540                 return 0;
 541
 542         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 543         size_t datalen = sizeof(out);
 544         time_t now = odhcpd_time();
 545
 546         if (status) {
 547                 struct __attribute__((packed)) {
 548                         uint16_t type;
 549                         uint16_t len;
 550                         uint16_t value;
 551                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 552                                 htons(status)};
 553
 554                 memcpy(buf + datalen, &stat, sizeof(stat));
 555                 datalen += sizeof(stat);
 556         } else {
 557                 if (a) {
 558                         uint32_t pref = 3600;
 559                         uint32_t valid = 3600;
 560
 561                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 562                                 bool match = true;
 563                                 if (iface->ia_addr[i].has_class) {
 564                                         match = false;
 565                                         if (a->classes_cnt) {
 566                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 567                                                         if (a->classes[j] == iface->ia_addr[i].class)
 568                                                                 match = true;
 569                                         } else if (a->all_class) {
 570                                                 match = true;
 571                                         }
 572                                 }
 573
 574                                 if (!match)
 575                                         continue;
 576
 577                                 uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
 578                                 uint32_t prefix_valid = iface->ia_addr[i].valid - now;
 579
 580                                 if (iface->ia_addr[i].prefix > 64 ||
 581                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 582                                         continue;
 583
 584                                 if (prefix_pref > 86400)
 585                                         prefix_pref = 86400;
 586
 587                                 if (prefix_valid > 86400)
 588                                         prefix_valid = 86400;
 589
 590 #ifdef DHCPV6_OPT_PREFIX_CLASS
 591                                 struct {
 592                                         uint16_t code;
 593                                         uint16_t length;
 594                                         uint16_t class;
 595                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 596                                         htons(2), htons(iface->ia_addr[i].class)};
 597 #endif
 598
 599                                 if (a->length < 128) {
 600                                         struct dhcpv6_ia_prefix p = {
 601                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 602                                                 .len = htons(sizeof(p) - 4),
 603                                                 .preferred = htonl(prefix_pref),
 604                                                 .valid = htonl(prefix_valid),
 605                                                 .prefix = a->length,
 606                                                 .addr = iface->ia_addr[i].addr
 607                                         };
 608                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 609                                         size_t entrlen = sizeof(p) - 4;
 610
 611 #ifdef DHCPV6_OPT_PREFIX_CLASS
 612                                         if (iface->ia_addr[i].has_class) {
 613                                                 entrlen += sizeof(pclass);
 614                                                 p.len = htons(entrlen);
 615                                         }
 616 #endif
 617
 618                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 619                                                 continue;
 620
 621                                         memcpy(buf + datalen, &p, sizeof(p));
 622 #ifdef DHCPV6_OPT_PREFIX_CLASS
 623                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 624 #endif
 625                                         datalen += entrlen + 4;
 626                                 } else {
 627                                         struct dhcpv6_ia_addr n = {
 628                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 629                                                 .len = htons(sizeof(n) - 4),
 630                                                 .addr = iface->ia_addr[i].addr,
 631                                                 .preferred = htonl(prefix_pref),
 632                                                 .valid = htonl(prefix_valid)
 633                                         };
 634                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 635                                         size_t entrlen = sizeof(n) - 4;
 636
 637 #ifdef DHCPV6_OPT_PREFIX_CLASS
 638                                         if (iface->ia_addr[i].has_class) {
 639                                                 entrlen += sizeof(pclass);
 640                                                 n.len = htons(entrlen);
 641                                         }
 642 #endif
 643
 644                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 645                                                 continue;
 646
 647                                         memcpy(buf + datalen, &n, sizeof(n));
 648 #ifdef DHCPV6_OPT_PREFIX_CLASS
 649                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 650 #endif
 651                                         datalen += entrlen + 4;
 652                                 }
 653
 654                                 // Calculate T1 / T2 based on non-deprecated addresses
 655                                 if (prefix_pref > 0) {
 656                                         if (prefix_pref < pref)
 657                                                 pref = prefix_pref;
 658
 659                                         if (prefix_valid < valid)
 660                                                 valid = prefix_valid;
 661                                 }
 662                         }
 663
 664                         a->valid_until = valid + now;
 665                         out.t1 = htonl(pref * 5 / 10);
 666                         out.t2 = htonl(pref * 8 / 10);
 667
 668                         if (!out.t1)
 669                                 out.t1 = htonl(1);
 670
 671                         if (!out.t2)
 672                                 out.t2 = htonl(1);
 673                 }
 674
 675                 if (!request) {
 676                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 677                         uint16_t otype, olen;
 678                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 679                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 680                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 681                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 682                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 683                                         continue;
 684
 685                                 bool found = false;
 686                                 if (a) {
 687                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 688                                                 if (iface->ia_addr[i].prefix > 64 ||
 689                                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 690                                                         continue;
 691
 692                                                 struct in6_addr addr = iface->ia_addr[i].addr;
 693                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 694                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 695
 696                                                         if (IN6_ARE_ADDR_EQUAL(&p->addr, &addr) &&
 697                                                                         p->prefix == a->length)
 698                                                                 found = true;
 699                                                 } else {
 700                                                         addr.s6_addr32[3] = htonl(a->assigned);
 701
 702                                                         if (IN6_ARE_ADDR_EQUAL(&n->addr, &addr))
 703                                                                 found = true;
 704                                                 }
 705                                         }
 706                                 }
 707
 708                                 if (!found) {
 709                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 710                                                 struct dhcpv6_ia_prefix inv = {
 711                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 712                                                         .len = htons(sizeof(inv) - 4),
 713                                                         .preferred = 0,
 714                                                         .valid = 0,
 715                                                         .prefix = p->prefix,
 716                                                         .addr = p->addr
 717                                                 };
 718
 719                                                 if (datalen + sizeof(inv) > buflen)
 720                                                         continue;
 721
 722                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 723                                                 datalen += sizeof(inv);
 724                                         } else {
 725                                                 struct dhcpv6_ia_addr inv = {
 726                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 727                                                         .len = htons(sizeof(inv) - 4),
 728                                                         .addr = n->addr,
 729                                                         .preferred = 0,
 730                                                         .valid = 0
 731                                                 };
 732
 733                                                 if (datalen + sizeof(inv) > buflen)
 734                                                         continue;
 735
 736                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 737                                                 datalen += sizeof(inv);
 738                                         }
 739                                 }
 740                         }
 741                 }
 742         }
 743
 744         out.len = htons(datalen - 4);
 745         memcpy(buf, &out, sizeof(out));
 746         return datalen;
 747 }
 748
 749
 750 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 751                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 752 {
 753         time_t now = odhcpd_time();
 754         size_t response_len = 0;
 755         const struct dhcpv6_client_header *hdr = data;
 756         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 757         uint16_t otype, olen;
 758
 759         // Find and parse client-id and hostname
 760         bool accept_reconf = false;
 761         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 762         char hostname[256];
 763         size_t hostname_len = 0;
 764         bool class_oro = false;
 765         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 766                 if (otype == DHCPV6_OPT_CLIENTID) {
 767                         clid_data = odata;
 768                         clid_len = olen;
 769
 770                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 771                                 memcpy(mac, &odata[8], sizeof(mac));
 772                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 773                                 memcpy(mac, &odata[4], sizeof(mac));
 774                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 775                         uint8_t fqdn_buf[256];
 776                         memcpy(fqdn_buf, odata, olen);
 777                         fqdn_buf[olen++] = 0;
 778
 779                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 780                                 hostname_len = strcspn(hostname, ".");
 781                 } else if (otype == DHCPV6_OPT_ORO) {
 782 #ifdef DHCPV6_OPT_PREFIX_CLASS
 783                         for (size_t i = 0; i + 1 < olen; i += 2) {
 784                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 785                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 786                                         class_oro = true;
 787                         }
 788 #endif
 789                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 790                         accept_reconf = true;
 791                 }
 792         }
 793
 794         if (!clid_data || !clid_len || clid_len > 130)
 795                 goto out;
 796
 797         update(iface);
 798         bool update_state = false;
 799
 800         struct dhcpv6_assignment *first = NULL;
 801         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 802                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 803                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 804                 if (!is_pd && !is_na)
 805                         continue;
 806
 807                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 808                 size_t ia_response_len = 0;
 809                 uint8_t reqlen = (is_pd) ? 62 : 128;
 810                 uint32_t reqhint = 0;
 811
 812                 const uint8_t classes_max = 32;
 813                 uint8_t classes_cnt = 0;
 814                 uint16_t classes[classes_max];
 815
 816                 // Parse request hint for IA-PD
 817                 if (is_pd) {
 818                         uint8_t *sdata;
 819                         uint16_t stype, slen;
 820                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 821                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 822                                         continue;
 823
 824                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 825                                 if (p->prefix) {
 826                                         reqlen = p->prefix;
 827                                         reqhint = ntohl(p->addr.s6_addr32[1]);
 828                                         if (reqlen > 32 && reqlen <= 64)
 829                                                 reqhint &= (1U << (64 - reqlen)) - 1;
 830                                 }
 831
 832 #ifdef DHCPV6_OPT_PREFIX_CLASS
 833                                 uint8_t *xdata;
 834                                 uint16_t xtype, xlen;
 835                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 836                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 837                                                 continue;
 838
 839                                         if (classes_cnt >= classes_max)
 840                                                 continue;
 841
 842                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 843                                 }
 844 #endif
 845                         }
 846
 847                         if (reqlen > 64)
 848                                 reqlen = 64;
 849                 } else if (is_na) {
 850                         uint8_t *sdata;
 851                         uint16_t stype, slen;
 852                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 853                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
 854                                         continue;
 855
 856 #ifdef DHCPV6_OPT_PREFIX_CLASS
 857                                 uint8_t *xdata;
 858                                 uint16_t xtype, xlen;
 859                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
 860                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 861                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 862                                                 continue;
 863
 864                                         if (classes_cnt >= classes_max)
 865                                                 continue;
 866
 867                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 868                                 }
 869 #endif
 870                         }
 871                 }
 872
 873                 // Find assignment
 874                 struct dhcpv6_assignment *c, *a = NULL;
 875                 list_for_each_entry(c, &iface->ia_assignments, head) {
 876                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
 877                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
 878                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
 879                                         (c->iaid == ia->iaid || c->valid_until < now) &&
 880                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
 881                                 a = c;
 882
 883                                 // Reset state
 884                                 apply_lease(iface, a, false);
 885                                 memcpy(a->clid_data, clid_data, clid_len);
 886                                 a->clid_len = clid_len;
 887                                 a->iaid = ia->iaid;
 888                                 a->peer = *addr;
 889                                 a->reconf_cnt = 0;
 890                                 a->reconf_sent = 0;
 891                                 a->all_class = class_oro;
 892                                 a->classes_cnt = classes_cnt;
 893                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
 894                                 if (a->classes)
 895                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 896                                 break;
 897                         }
 898                 }
 899
 900                 // Generic message handling
 901                 uint16_t status = DHCPV6_STATUS_OK;
 902                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
 903                         bool assigned = !!a;
 904
 905                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
 906                                 a = calloc(1, sizeof(*a) + clid_len);
 907                                 if (a) {
 908                                         a->clid_len = clid_len;
 909                                         a->iaid = ia->iaid;
 910                                         a->length = reqlen;
 911                                         a->peer = *addr;
 912                                         a->assigned = reqhint;
 913                                         a->all_class = class_oro;
 914                                         a->classes_cnt = classes_cnt;
 915                                         if (classes_cnt) {
 916                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
 917                                                 if (a->classes)
 918                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 919                                         }
 920
 921                                         if (first)
 922                                                 memcpy(a->key, first->key, sizeof(a->key));
 923                                         else
 924                                                 odhcpd_urandom(a->key, sizeof(a->key));
 925                                         memcpy(a->clid_data, clid_data, clid_len);
 926
 927                                         if (is_pd)
 928                                                 while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64);
 929                                         else
 930                                                 assigned = assign_na(iface, a);
 931                                 }
 932                         }
 933
 934                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
 935                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
 936                         } else if (assigned && !first) { //
 937                                 size_t handshake_len = 4;
 938                                 buf[0] = 0;
 939                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
 940                                 buf[2] = 0;
 941                                 buf[3] = 0;
 942
 943                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
 944                                         struct dhcpv6_auth_reconfigure auth = {
 945                                                 htons(DHCPV6_OPT_AUTH),
 946                                                 htons(sizeof(auth) - 4),
 947                                                 3, 1, 0,
 948                                                 {htonl(time(NULL)), htonl(++serial)},
 949                                                 1,
 950                                                 {0}
 951                                         };
 952                                         memcpy(auth.key, a->key, sizeof(a->key));
 953                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
 954                                         handshake_len += sizeof(auth);
 955                                 }
 956
 957                                 buf += handshake_len;
 958                                 buflen -= handshake_len;
 959                                 response_len += handshake_len;
 960
 961                                 first = a;
 962                         }
 963
 964                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
 965
 966                         // Was only a solicitation: mark binding for removal
 967                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
 968                                 a->valid_until = 0;
 969                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
 970                                 if (hostname_len > 0) {
 971                                         a->hostname = realloc(a->hostname, hostname_len + 1);
 972                                         if (a->hostname) {
 973                                                 memcpy(a->hostname, hostname, hostname_len);
 974                                                 a->hostname[hostname_len] = 0;
 975                                         }
 976                                 }
 977                                 a->accept_reconf = accept_reconf;
 978                                 apply_lease(iface, a, true);
 979                                 update_state = true;
 980                         } else if (!assigned && a) { // Cleanup failed assignment
 981                                 free(a->classes);
 982                                 free(a->hostname);
 983                                 free(a);
 984                         }
 985                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
 986                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
 987                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
 988                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
 989                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
 990                                 status = DHCPV6_STATUS_NOBINDING;
 991                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
 992                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
 993                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
 994                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
 995                                 if (a)
 996                                         apply_lease(iface, a, true);
 997                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
 998                                 a->valid_until = 0;
 999                                 apply_lease(iface, a, false);
1000                                 update_state = true;
1001                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1002                                 a->clid_len = 0;
1003                                 a->valid_until = now + 3600; // Block address for 1h
1004                                 update_state = true;
1005                         }
1006                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1007                         // Always send NOTONLINK for CONFIRM so that clients restart connection
1008                         status = DHCPV6_STATUS_NOTONLINK;
1009                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1010                 }
1011
1012                 buf += ia_response_len;
1013                 buflen -= ia_response_len;
1014                 response_len += ia_response_len;
1015         }
1016
1017         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1018                 buf[0] = 0;
1019                 buf[1] = DHCPV6_OPT_STATUS;
1020                 buf[2] = 0;
1021                 buf[3] = 2;
1022                 buf[4] = 0;
1023                 buf[5] = DHCPV6_STATUS_OK;
1024                 response_len += 6;
1025         }
1026
1027         if (update_state)
1028                 dhcpv6_write_statefile();
1029
1030 out:
1031         return response_len;
1032 }