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