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 uint32_t serial = 0;
  36 static uint8_t statemd5[16];
  37
  38
  39 int dhcpv6_ia_init(void)
  40 {
  41         uloop_timeout_set(&reconf_event, 2000);
  42         return 0;
  43 }
  44
  45
  46 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  47 {
  48         if (!enable && iface->ia_assignments.next) {
  49                 struct dhcpv6_assignment *c;
  50                 while (!list_empty(&iface->ia_assignments)) {
  51                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  52                         list_del(&c->head);
  53                         free(c->hostname);
  54                         free(c->classes);
  55                         free(c);
  56                 }
  57         }
  58
  59         if (iface->dhcpv6 == RELAYD_SERVER) {
  60                 if (!iface->ia_assignments.next)
  61                         INIT_LIST_HEAD(&iface->ia_assignments);
  62
  63                 if (list_empty(&iface->ia_assignments)) {
  64                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  65                         if (!border) {
  66                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  67                                 return -1;
  68                         }
  69
  70                         border->length = 64;
  71                         list_add(&border->head, &iface->ia_assignments);
  72                 }
  73
  74                 update(iface);
  75
  76                 // Parse static entries
  77                 struct lease *lease;
  78                 list_for_each_entry(lease, &leases, head) {
  79                         // Construct entry
  80                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  81                         if (!a) {
  82                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  83                                         iface->ifname);
  84                                 return -1;
  85                         }
  86
  87                         a->clid_len = lease->duid_len;
  88                         a->length = 128;
  89                         if (lease->hostid) {
  90                                 a->assigned = lease->hostid;
  91                         } else {
  92                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  93                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
  94                         }
  95                         odhcpd_urandom(a->key, sizeof(a->key));
  96                         memcpy(a->clid_data, lease->duid, a->clid_len);
  97                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
  98
  99                         // Assign to all interfaces
 100                         struct dhcpv6_assignment *c;
 101                         list_for_each_entry(c, &iface->ia_assignments, head) {
 102                                 if (c->length != 128 || c->assigned > a->assigned) {
 103                                         list_add_tail(&a->head, &c->head);
 104                                 } else if (c->assigned == a->assigned) {
 105                                         // Already an assignment with that number
 106                                         break;
 107                                 }
 108                         }
 109
 110                         if (a->head.next) {
 111                                 if (lease->hostname[0]) {
 112                                         free(a->hostname);
 113                                         a->hostname = strdup(lease->hostname);
 114                                 }
 115                         } else {
 116                                 free(a->classes);
 117                                 free(a->hostname);
 118                                 free(a);
 119                         }
 120                 }
 121         }
 122         return 0;
 123 }
 124
 125
 126 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 127 {
 128         struct {
 129                 struct dhcpv6_client_header hdr;
 130                 uint16_t srvid_type;
 131                 uint16_t srvid_len;
 132                 uint16_t duid_type;
 133                 uint16_t hardware_type;
 134                 uint8_t mac[6];
 135                 uint16_t msg_type;
 136                 uint16_t msg_len;
 137                 uint8_t msg_id;
 138                 struct dhcpv6_auth_reconfigure auth;
 139                 uint16_t clid_type;
 140                 uint16_t clid_len;
 141                 uint8_t clid_data[128];
 142         } __attribute__((packed)) reconf_msg = {
 143                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 144                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 145                 .srvid_len = htons(10),
 146                 .duid_type = htons(3),
 147                 .hardware_type = htons(1),
 148                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 149                 .msg_len = htons(1),
 150                 .msg_id = DHCPV6_MSG_RENEW,
 151                 .auth = {htons(DHCPV6_OPT_AUTH),
 152                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 153                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 154                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 155                 .clid_len = htons(assign->clid_len),
 156                 .clid_data = {0},
 157         };
 158
 159         odhcpd_get_mac(iface, reconf_msg.mac);
 160         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 161         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 162
 163         md5_ctx_t md5;
 164         uint8_t secretbytes[16];
 165         memcpy(secretbytes, assign->key, sizeof(secretbytes));
 166
 167         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 168                 secretbytes[i] ^= 0x36;
 169
 170         md5_begin(&md5);
 171         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 172         md5_hash(iov.iov_base, iov.iov_len, &md5);
 173         md5_end(reconf_msg.auth.key, &md5);
 174
 175         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 176                 secretbytes[i] ^= 0x36;
 177                 secretbytes[i] ^= 0x5c;
 178         }
 179
 180         md5_begin(&md5);
 181         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 182         md5_hash(reconf_msg.auth.key, 16, &md5);
 183         md5_end(reconf_msg.auth.key, &md5);
 184
 185         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 186 }
 187
 188
 189 void dhcpv6_write_statefile(void)
 190 {
 191         md5_ctx_t md5;
 192         md5_begin(&md5);
 193
 194         if (config.dhcp_statefile) {
 195                 time_t now = odhcpd_time(), wall_time = time(NULL);
 196                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 197                 if (fd < 0)
 198                         return;
 199
 200                 lockf(fd, F_LOCK, 0);
 201                 ftruncate(fd, 0);
 202
 203                 FILE *fp = fdopen(fd, "w");
 204                 if (!fp) {
 205                         close(fd);
 206                         return;
 207                 }
 208
 209                 struct interface *iface;
 210                 list_for_each_entry(iface, &interfaces, head) {
 211                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 212                                 continue;
 213
 214                         if (iface->dhcpv6 == RELAYD_SERVER) {
 215                                 struct dhcpv6_assignment *c;
 216                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 217                                         if (c->clid_len == 0)
 218                                                 continue;
 219
 220                                         char ipbuf[INET6_ADDRSTRLEN];
 221                                         char leasebuf[512];
 222                                         char duidbuf[264];
 223                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 224
 225                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 226                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 227                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 228                                                         (c->hostname ? c->hostname : "-"),
 229                                                         (unsigned)(c->valid_until > now ?
 230                                                                         (c->valid_until - now + wall_time) : 0),
 231                                                         c->assigned, (unsigned)c->length);
 232
 233                                         struct in6_addr addr;
 234                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 235                                                 if (iface->ia_addr[i].prefix > 64)
 236                                                         continue;
 237
 238                                                 addr = iface->ia_addr[i].addr;
 239                                                 if (c->length == 128)
 240                                                         addr.s6_addr32[3] = htonl(c->assigned);
 241                                                 else
 242                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 243                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 244
 245                                                 if (c->length == 128 && c->hostname && i == 0) {
 246                                                         fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
 247                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 248                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 249                                                 }
 250
 251                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length);
 252                                         }
 253                                         leasebuf[l - 1] = '\n';
 254                                         fwrite(leasebuf, 1, l, fp);
 255                                 }
 256                         }
 257
 258                         if (iface->dhcpv4 == RELAYD_SERVER) {
 259                                 struct dhcpv4_assignment *c;
 260                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 261                                         char ipbuf[INET6_ADDRSTRLEN];
 262                                         char leasebuf[512];
 263                                         char duidbuf[16];
 264                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 265
 266                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 267                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 268                                                         iface->ifname, duidbuf,
 269                                                         (c->hostname ? c->hostname : "-"),
 270                                                         (unsigned)(c->valid_until > now ?
 271                                                                         (c->valid_until - now + wall_time) : 0),
 272                                                         c->addr);
 273
 274                                         struct in_addr addr = {htonl(c->addr)};
 275                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 276
 277                                         if (c->hostname[0]) {
 278                                                 fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
 279                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 280                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 281                                         }
 282
 283                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 284                                         leasebuf[l - 1] = '\n';
 285                                         fwrite(leasebuf, 1, l, fp);
 286                                 }
 287                         }
 288                 }
 289
 290                 fclose(fp);
 291         }
 292
 293         uint8_t newmd5[16];
 294         md5_end(newmd5, &md5);
 295
 296         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 297                 memcpy(statemd5, newmd5, sizeof(statemd5));
 298                 char *argv[2] = {config.dhcp_cb, NULL};
 299                 if (!vfork()) {
 300                         execv(argv[0], argv);
 301                         _exit(128);
 302                 }
 303         }
 304 }
 305
 306
 307 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 308 {
 309         if (a->length > 64)
 310                 return;
 311
 312         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 313                 struct in6_addr prefix = iface->ia_addr[i].addr;
 314                 prefix.s6_addr32[1] |= htonl(a->assigned);
 315                 odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add);
 316         }
 317 }
 318
 319
 320 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 321 {
 322         struct dhcpv6_assignment *c;
 323         if (iface->ia_addr_len < 1)
 324                 return false;
 325
 326         // Try honoring the hint first
 327         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 328         if (assign->assigned) {
 329                 list_for_each_entry(c, &iface->ia_assignments, head) {
 330                         if (c->length == 128)
 331                                 continue;
 332
 333                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 334                                 list_add_tail(&assign->head, &c->head);
 335                                 apply_lease(iface, assign, true);
 336                                 return true;
 337                         }
 338
 339                         if (c->assigned != 0)
 340                                 current = (c->assigned + (1 << (64 - c->length)));
 341                 }
 342         }
 343
 344         // Fallback to a variable assignment
 345         current = 1;
 346         list_for_each_entry(c, &iface->ia_assignments, head) {
 347                 if (c->length == 128)
 348                         continue;
 349
 350                 current = (current + asize) & (~asize);
 351                 if (current + asize < c->assigned) {
 352                         assign->assigned = current;
 353                         list_add_tail(&assign->head, &c->head);
 354                         apply_lease(iface, assign, true);
 355                         return true;
 356                 }
 357
 358                 if (c->assigned != 0)
 359                         current = (c->assigned + (1 << (64 - c->length)));
 360         }
 361
 362         return false;
 363 }
 364
 365
 366 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 367 {
 368         bool match = false;
 369         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 370                 if (!iface->ia_addr[i].has_class) {
 371                         match = true;
 372                         continue;
 373                 } else if (assign->classes_cnt) {
 374                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 375                                 if (assign->classes[j] == iface->ia_addr[i].class)
 376                                         match = true;
 377                 } else if (assign->all_class) {
 378                         match = true;
 379                 }
 380         }
 381
 382         if (!match)
 383                 return false;
 384
 385         // Seed RNG with checksum of DUID
 386         uint32_t seed = 0;
 387         for (size_t i = 0; i < assign->clid_len; ++i)
 388                 seed += assign->clid_data[i];
 389         srand(seed);
 390
 391         // Try to assign up to 100x
 392         for (size_t i = 0; i < 100; ++i) {
 393                 uint32_t try;
 394                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 395
 396                 struct dhcpv6_assignment *c;
 397                 list_for_each_entry(c, &iface->ia_assignments, head) {
 398                         if (c->assigned > try || c->length != 128) {
 399                                 assign->assigned = try;
 400                                 list_add_tail(&assign->head, &c->head);
 401                                 return true;
 402                         } else if (c->assigned == try) {
 403                                 break;
 404                         }
 405                 }
 406         }
 407
 408         return false;
 409 }
 410
 411
 412 static int prefixcmp(const void *va, const void *vb)
 413 {
 414         const struct odhcpd_ipaddr *a = va, *b = vb;
 415         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 416         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 417         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 418 }
 419
 420
 421 static void update(struct interface *iface)
 422 {
 423         struct odhcpd_ipaddr addr[8];
 424         memset(addr, 0, sizeof(addr));
 425         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 426
 427         if (len < 0)
 428                 return;
 429
 430         qsort(addr, len, sizeof(*addr), prefixcmp);
 431
 432         time_t now = odhcpd_time();
 433         int minprefix = -1;
 434
 435         for (int i = 0; i < len; ++i) {
 436                 if (addr[i].prefix > minprefix)
 437                         minprefix = addr[i].prefix;
 438
 439                 addr[i].addr.s6_addr32[2] = 0;
 440                 addr[i].addr.s6_addr32[3] = 0;
 441
 442                 if (addr[i].preferred < UINT32_MAX - now)
 443                         addr[i].preferred += now;
 444
 445                 if (addr[i].valid < UINT32_MAX - now)
 446                         addr[i].valid += now;
 447         }
 448
 449         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 450         border->assigned = 1 << (64 - minprefix);
 451
 452         bool change = len != (int)iface->ia_addr_len;
 453         for (int i = 0; !change && i < len; ++i)
 454                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 455                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 456                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 457                                 (addr[i].valid > (uint32_t)now + 7200) !=
 458                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 459                         change = true;
 460
 461         if (change) {
 462                 struct dhcpv6_assignment *c;
 463                 list_for_each_entry(c, &iface->ia_assignments, head)
 464                         if (c != border)
 465                                 apply_lease(iface, c, false);
 466         }
 467
 468         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 469         iface->ia_addr_len = len;
 470
 471         if (change) { // Addresses / prefixes have changed
 472                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 473                 struct dhcpv6_assignment *c, *d;
 474                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 475                         if (c->clid_len == 0 || c->valid_until < now)
 476                                 continue;
 477
 478                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 479                                 list_move(&c->head, &reassign);
 480                         else if (c != border)
 481                                 apply_lease(iface, c, true);
 482
 483                         if (c->accept_reconf && c->reconf_cnt == 0) {
 484                                 c->reconf_cnt = 1;
 485                                 c->reconf_sent = now;
 486                                 send_reconf(iface, c);
 487
 488                                 // Leave all other assignments of that client alone
 489                                 struct dhcpv6_assignment *a;
 490                                 list_for_each_entry(a, &iface->ia_assignments, head)
 491                                         if (a != c && a->clid_len == c->clid_len &&
 492                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 493                                                 c->reconf_cnt = INT_MAX;
 494                         }
 495                 }
 496
 497                 while (!list_empty(&reassign)) {
 498                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 499                         list_del(&c->head);
 500                         if (!assign_pd(iface, c)) {
 501                                 c->assigned = 0;
 502                                 list_add(&c->head, &iface->ia_assignments);
 503                         }
 504                 }
 505
 506                 dhcpv6_write_statefile();
 507         }
 508 }
 509
 510
 511 static void reconf_timer(struct uloop_timeout *event)
 512 {
 513         time_t now = odhcpd_time();
 514         struct interface *iface;
 515         list_for_each_entry(iface, &interfaces, head) {
 516                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 517                         continue;
 518
 519                 struct dhcpv6_assignment *a, *n;
 520                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 521                         if (a->valid_until < now) {
 522                                 if ((a->length < 128 && a->clid_len > 0) ||
 523                                                 (a->length == 128 && a->clid_len == 0)) {
 524                                         list_del(&a->head);
 525                                         free(a->classes);
 526                                         free(a->hostname);
 527                                         free(a);
 528                                 }
 529                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 530                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 531                                 ++a->reconf_cnt;
 532                                 a->reconf_sent = now;
 533                                 send_reconf(iface, a);
 534                         }
 535                 }
 536
 537                 if (iface->ia_reconf) {
 538                         update(iface);
 539                         iface->ia_reconf = false;
 540                 }
 541         }
 542
 543         uloop_timeout_set(event, 2000);
 544 }
 545
 546
 547 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 548                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 549                 struct interface *iface, bool request)
 550 {
 551         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 552                 return 0;
 553
 554         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 555         size_t datalen = sizeof(out);
 556         time_t now = odhcpd_time();
 557
 558         if (status) {
 559                 struct __attribute__((packed)) {
 560                         uint16_t type;
 561                         uint16_t len;
 562                         uint16_t value;
 563                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 564                                 htons(status)};
 565
 566                 memcpy(buf + datalen, &stat, sizeof(stat));
 567                 datalen += sizeof(stat);
 568         } else {
 569                 if (a) {
 570                         uint32_t pref = 3600;
 571                         uint32_t valid = 3600;
 572
 573                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 574                                 bool match = true;
 575                                 if (iface->ia_addr[i].has_class) {
 576                                         match = false;
 577                                         if (a->classes_cnt) {
 578                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 579                                                         if (a->classes[j] == iface->ia_addr[i].class)
 580                                                                 match = true;
 581                                         } else if (a->all_class) {
 582                                                 match = true;
 583                                         }
 584                                 }
 585
 586                                 if (!match)
 587                                         continue;
 588
 589                                 uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
 590                                 uint32_t prefix_valid = iface->ia_addr[i].valid - now;
 591
 592                                 if (iface->ia_addr[i].prefix > 64 ||
 593                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 594                                         continue;
 595
 596                                 if (prefix_pref > 86400)
 597                                         prefix_pref = 86400;
 598
 599                                 if (prefix_valid > 86400)
 600                                         prefix_valid = 86400;
 601
 602 #ifdef DHCPV6_OPT_PREFIX_CLASS
 603                                 struct {
 604                                         uint16_t code;
 605                                         uint16_t length;
 606                                         uint16_t class;
 607                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 608                                         htons(2), htons(iface->ia_addr[i].class)};
 609 #endif
 610
 611                                 if (a->length < 128) {
 612                                         struct dhcpv6_ia_prefix p = {
 613                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 614                                                 .len = htons(sizeof(p) - 4),
 615                                                 .preferred = htonl(prefix_pref),
 616                                                 .valid = htonl(prefix_valid),
 617                                                 .prefix = a->length,
 618                                                 .addr = iface->ia_addr[i].addr
 619                                         };
 620                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 621                                         size_t entrlen = sizeof(p) - 4;
 622
 623 #ifdef DHCPV6_OPT_PREFIX_CLASS
 624                                         if (iface->ia_addr[i].has_class) {
 625                                                 entrlen += sizeof(pclass);
 626                                                 p.len = htons(entrlen);
 627                                         }
 628 #endif
 629
 630                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 631                                                 continue;
 632
 633                                         memcpy(buf + datalen, &p, sizeof(p));
 634 #ifdef DHCPV6_OPT_PREFIX_CLASS
 635                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 636 #endif
 637                                         datalen += entrlen + 4;
 638                                 } else {
 639                                         struct dhcpv6_ia_addr n = {
 640                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 641                                                 .len = htons(sizeof(n) - 4),
 642                                                 .addr = iface->ia_addr[i].addr,
 643                                                 .preferred = htonl(prefix_pref),
 644                                                 .valid = htonl(prefix_valid)
 645                                         };
 646                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 647                                         size_t entrlen = sizeof(n) - 4;
 648
 649 #ifdef DHCPV6_OPT_PREFIX_CLASS
 650                                         if (iface->ia_addr[i].has_class) {
 651                                                 entrlen += sizeof(pclass);
 652                                                 n.len = htons(entrlen);
 653                                         }
 654 #endif
 655
 656                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 657                                                 continue;
 658
 659                                         memcpy(buf + datalen, &n, sizeof(n));
 660 #ifdef DHCPV6_OPT_PREFIX_CLASS
 661                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 662 #endif
 663                                         datalen += entrlen + 4;
 664                                 }
 665
 666                                 // Calculate T1 / T2 based on non-deprecated addresses
 667                                 if (prefix_pref > 0) {
 668                                         if (prefix_pref < pref)
 669                                                 pref = prefix_pref;
 670
 671                                         if (prefix_valid < valid)
 672                                                 valid = prefix_valid;
 673                                 }
 674                         }
 675
 676                         a->valid_until = valid + now;
 677                         out.t1 = htonl(pref * 5 / 10);
 678                         out.t2 = htonl(pref * 8 / 10);
 679
 680                         if (!out.t1)
 681                                 out.t1 = htonl(1);
 682
 683                         if (!out.t2)
 684                                 out.t2 = htonl(1);
 685                 }
 686
 687                 if (!request) {
 688                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 689                         uint16_t otype, olen;
 690                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 691                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 692                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 693                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 694                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 695                                         continue;
 696
 697                                 bool found = false;
 698                                 if (a) {
 699                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 700                                                 if (iface->ia_addr[i].prefix > 64 ||
 701                                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 702                                                         continue;
 703
 704                                                 struct in6_addr addr = iface->ia_addr[i].addr;
 705                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 706                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 707
 708                                                         if (IN6_ARE_ADDR_EQUAL(&p->addr, &addr) &&
 709                                                                         p->prefix == a->length)
 710                                                                 found = true;
 711                                                 } else {
 712                                                         addr.s6_addr32[3] = htonl(a->assigned);
 713
 714                                                         if (IN6_ARE_ADDR_EQUAL(&n->addr, &addr))
 715                                                                 found = true;
 716                                                 }
 717                                         }
 718                                 }
 719
 720                                 if (!found) {
 721                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 722                                                 struct dhcpv6_ia_prefix inv = {
 723                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 724                                                         .len = htons(sizeof(inv) - 4),
 725                                                         .preferred = 0,
 726                                                         .valid = 0,
 727                                                         .prefix = p->prefix,
 728                                                         .addr = p->addr
 729                                                 };
 730
 731                                                 if (datalen + sizeof(inv) > buflen)
 732                                                         continue;
 733
 734                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 735                                                 datalen += sizeof(inv);
 736                                         } else {
 737                                                 struct dhcpv6_ia_addr inv = {
 738                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 739                                                         .len = htons(sizeof(inv) - 4),
 740                                                         .addr = n->addr,
 741                                                         .preferred = 0,
 742                                                         .valid = 0
 743                                                 };
 744
 745                                                 if (datalen + sizeof(inv) > buflen)
 746                                                         continue;
 747
 748                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 749                                                 datalen += sizeof(inv);
 750                                         }
 751                                 }
 752                         }
 753                 }
 754         }
 755
 756         out.len = htons(datalen - 4);
 757         memcpy(buf, &out, sizeof(out));
 758         return datalen;
 759 }
 760
 761
 762 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 763                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 764 {
 765         time_t now = odhcpd_time();
 766         size_t response_len = 0;
 767         const struct dhcpv6_client_header *hdr = data;
 768         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 769         uint16_t otype, olen;
 770
 771         // Find and parse client-id and hostname
 772         bool accept_reconf = false;
 773         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 774         char hostname[256];
 775         size_t hostname_len = 0;
 776         bool class_oro = false;
 777         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 778                 if (otype == DHCPV6_OPT_CLIENTID) {
 779                         clid_data = odata;
 780                         clid_len = olen;
 781
 782                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 783                                 memcpy(mac, &odata[8], sizeof(mac));
 784                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 785                                 memcpy(mac, &odata[4], sizeof(mac));
 786                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 787                         uint8_t fqdn_buf[256];
 788                         memcpy(fqdn_buf, odata, olen);
 789                         fqdn_buf[olen++] = 0;
 790
 791                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 792                                 hostname_len = strcspn(hostname, ".");
 793                 } else if (otype == DHCPV6_OPT_ORO) {
 794 #ifdef DHCPV6_OPT_PREFIX_CLASS
 795                         for (size_t i = 0; i + 1 < olen; i += 2) {
 796                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 797                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 798                                         class_oro = true;
 799                         }
 800 #endif
 801                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 802                         accept_reconf = true;
 803                 }
 804         }
 805
 806         if (!clid_data || !clid_len || clid_len > 130)
 807                 goto out;
 808
 809         update(iface);
 810         bool update_state = false;
 811
 812         struct dhcpv6_assignment *first = NULL;
 813         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 814                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 815                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 816                 if (!is_pd && !is_na)
 817                         continue;
 818
 819                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 820                 size_t ia_response_len = 0;
 821                 uint8_t reqlen = (is_pd) ? 62 : 128;
 822                 uint32_t reqhint = 0;
 823
 824                 const uint8_t classes_max = 32;
 825                 uint8_t classes_cnt = 0;
 826                 uint16_t classes[classes_max];
 827
 828                 // Parse request hint for IA-PD
 829                 if (is_pd) {
 830                         uint8_t *sdata;
 831                         uint16_t stype, slen;
 832                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 833                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 834                                         continue;
 835
 836                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 837                                 if (p->prefix) {
 838                                         reqlen = p->prefix;
 839                                         reqhint = ntohl(p->addr.s6_addr32[1]);
 840                                         if (reqlen > 32 && reqlen <= 64)
 841                                                 reqhint &= (1U << (64 - reqlen)) - 1;
 842                                 }
 843
 844 #ifdef DHCPV6_OPT_PREFIX_CLASS
 845                                 uint8_t *xdata;
 846                                 uint16_t xtype, xlen;
 847                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 848                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 849                                                 continue;
 850
 851                                         if (classes_cnt >= classes_max)
 852                                                 continue;
 853
 854                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 855                                 }
 856 #endif
 857                         }
 858
 859                         if (reqlen > 64)
 860                                 reqlen = 64;
 861                 } else if (is_na) {
 862                         uint8_t *sdata;
 863                         uint16_t stype, slen;
 864                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 865                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
 866                                         continue;
 867
 868 #ifdef DHCPV6_OPT_PREFIX_CLASS
 869                                 uint8_t *xdata;
 870                                 uint16_t xtype, xlen;
 871                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
 872                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 873                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 874                                                 continue;
 875
 876                                         if (classes_cnt >= classes_max)
 877                                                 continue;
 878
 879                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 880                                 }
 881 #endif
 882                         }
 883                 }
 884
 885                 // Find assignment
 886                 struct dhcpv6_assignment *c, *a = NULL;
 887                 list_for_each_entry(c, &iface->ia_assignments, head) {
 888                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
 889                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
 890                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
 891                                         (c->iaid == ia->iaid || c->valid_until < now) &&
 892                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
 893                                 a = c;
 894
 895                                 // Reset state
 896                                 apply_lease(iface, a, false);
 897                                 memcpy(a->clid_data, clid_data, clid_len);
 898                                 a->clid_len = clid_len;
 899                                 a->iaid = ia->iaid;
 900                                 a->peer = *addr;
 901                                 a->reconf_cnt = 0;
 902                                 a->reconf_sent = 0;
 903                                 a->all_class = class_oro;
 904                                 a->classes_cnt = classes_cnt;
 905                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
 906                                 if (a->classes)
 907                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 908                                 break;
 909                         }
 910                 }
 911
 912                 // Generic message handling
 913                 uint16_t status = DHCPV6_STATUS_OK;
 914                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
 915                         bool assigned = !!a;
 916
 917                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
 918                                 a = calloc(1, sizeof(*a) + clid_len);
 919                                 if (a) {
 920                                         a->clid_len = clid_len;
 921                                         a->iaid = ia->iaid;
 922                                         a->length = reqlen;
 923                                         a->peer = *addr;
 924                                         a->assigned = reqhint;
 925                                         a->all_class = class_oro;
 926                                         a->classes_cnt = classes_cnt;
 927                                         if (classes_cnt) {
 928                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
 929                                                 if (a->classes)
 930                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 931                                         }
 932
 933                                         if (first)
 934                                                 memcpy(a->key, first->key, sizeof(a->key));
 935                                         else
 936                                                 odhcpd_urandom(a->key, sizeof(a->key));
 937                                         memcpy(a->clid_data, clid_data, clid_len);
 938
 939                                         if (is_pd)
 940                                                 while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64);
 941                                         else
 942                                                 assigned = assign_na(iface, a);
 943                                 }
 944                         }
 945
 946                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
 947                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
 948                         } else if (assigned && !first) { //
 949                                 size_t handshake_len = 4;
 950                                 buf[0] = 0;
 951                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
 952                                 buf[2] = 0;
 953                                 buf[3] = 0;
 954
 955                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
 956                                         struct dhcpv6_auth_reconfigure auth = {
 957                                                 htons(DHCPV6_OPT_AUTH),
 958                                                 htons(sizeof(auth) - 4),
 959                                                 3, 1, 0,
 960                                                 {htonl(time(NULL)), htonl(++serial)},
 961                                                 1,
 962                                                 {0}
 963                                         };
 964                                         memcpy(auth.key, a->key, sizeof(a->key));
 965                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
 966                                         handshake_len += sizeof(auth);
 967                                 }
 968
 969                                 buf += handshake_len;
 970                                 buflen -= handshake_len;
 971                                 response_len += handshake_len;
 972
 973                                 first = a;
 974                         }
 975
 976                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
 977
 978                         // Was only a solicitation: mark binding for removal
 979                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
 980                                 a->valid_until = 0;
 981                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
 982                                 if (hostname_len > 0) {
 983                                         a->hostname = realloc(a->hostname, hostname_len + 1);
 984                                         if (a->hostname) {
 985                                                 memcpy(a->hostname, hostname, hostname_len);
 986                                                 a->hostname[hostname_len] = 0;
 987                                         }
 988                                 }
 989                                 a->accept_reconf = accept_reconf;
 990                                 apply_lease(iface, a, true);
 991                                 update_state = true;
 992                         } else if (!assigned && a) { // Cleanup failed assignment
 993                                 free(a->classes);
 994                                 free(a->hostname);
 995                                 free(a);
 996                         }
 997                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
 998                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
 999                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1000                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1001                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1002                                 status = DHCPV6_STATUS_NOBINDING;
1003                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1004                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1005                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1006                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1007                                 if (a)
1008                                         apply_lease(iface, a, true);
1009                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1010                                 a->valid_until = 0;
1011                                 apply_lease(iface, a, false);
1012                                 update_state = true;
1013                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1014                                 a->clid_len = 0;
1015                                 a->valid_until = now + 3600; // Block address for 1h
1016                                 update_state = true;
1017                         }
1018                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1019                         // Always send NOTONLINK for CONFIRM so that clients restart connection
1020                         status = DHCPV6_STATUS_NOTONLINK;
1021                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1022                 }
1023
1024                 buf += ia_response_len;
1025                 buflen -= ia_response_len;
1026                 response_len += ia_response_len;
1027         }
1028
1029         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1030                 buf[0] = 0;
1031                 buf[1] = DHCPV6_OPT_STATUS;
1032                 buf[2] = 0;
1033                 buf[3] = 2;
1034                 buf[4] = 0;
1035                 buf[5] = DHCPV6_STATUS_OK;
1036                 response_len += 6;
1037         }
1038
1039         if (update_state)
1040                 dhcpv6_write_statefile();
1041
1042 out:
1043         return response_len;
1044 }