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 "md5.h"
  19
  20 #include <time.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <alloca.h>
  24 #include <resolv.h>
  25 #include <limits.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <arpa/inet.h>
  29 #include <sys/timerfd.h>
  30
  31
  32 static void update(struct interface *iface);
  33 static void reconf_timer(struct uloop_timeout *event);
  34 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  35 static int socket_fd = -1;
  36 static uint32_t serial = 0;
  37
  38
  39 int dhcpv6_ia_init(int dhcpv6_socket)
  40 {
  41         socket_fd = dhcpv6_socket;
  42         uloop_timeout_set(&reconf_event, 2000);
  43         return 0;
  44 }
  45
  46
  47 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  48 {
  49         if (!enable && iface->ia_assignments.next) {
  50                 struct dhcpv6_assignment *c;
  51                 while (!list_empty(&iface->ia_assignments)) {
  52                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  53                         list_del(&c->head);
  54                         free(c);
  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                         border->length = 64;
  65                         list_add(&border->head, &iface->ia_assignments);
  66                 }
  67
  68                 update(iface);
  69
  70                 // Parse static entries
  71                 struct lease *lease;
  72                 list_for_each_entry(lease, &leases, head) {
  73                         // Construct entry
  74                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  75                         a->clid_len = lease->duid_len;
  76                         a->length = 128;
  77                         a->assigned = lease->hostid;
  78                         odhcpd_urandom(a->key, sizeof(a->key));
  79                         memcpy(a->clid_data, lease->duid, a->clid_len);
  80                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
  81
  82                         // Assign to all interfaces
  83                         struct dhcpv6_assignment *c;
  84                         list_for_each_entry(c, &iface->ia_assignments, head) {
  85                                 if (c->length != 128 || c->assigned > a->assigned) {
  86                                         list_add_tail(&a->head, &c->head);
  87                                 } else if (c->assigned == a->assigned) {
  88                                         // Already an assignment with that number
  89                                         break;
  90                                 }
  91                         }
  92
  93                         if (a->head.next) {
  94                                 if (lease->hostname[0]) {
  95                                         free(a->hostname);
  96                                         a->hostname = strdup(lease->hostname);
  97                                 }
  98                         } else {
  99                                 free(a);
 100                         }
 101                 }
 102         }
 103         return 0;
 104 }
 105
 106
 107 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 108 {
 109         struct {
 110                 struct dhcpv6_client_header hdr;
 111                 uint16_t srvid_type;
 112                 uint16_t srvid_len;
 113                 uint16_t duid_type;
 114                 uint16_t hardware_type;
 115                 uint8_t mac[6];
 116                 uint16_t msg_type;
 117                 uint16_t msg_len;
 118                 uint8_t msg_id;
 119                 struct dhcpv6_auth_reconfigure auth;
 120                 uint16_t clid_type;
 121                 uint16_t clid_len;
 122                 uint8_t clid_data[128];
 123         } __attribute__((packed)) reconf_msg = {
 124                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 125                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 126                 .srvid_len = htons(10),
 127                 .duid_type = htons(3),
 128                 .hardware_type = htons(1),
 129                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 130                 .msg_len = htons(1),
 131                 .msg_id = DHCPV6_MSG_RENEW,
 132                 .auth = {htons(DHCPV6_OPT_AUTH),
 133                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 134                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 135                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 136                 .clid_len = htons(assign->clid_len),
 137                 .clid_data = {0},
 138         };
 139
 140         odhcpd_get_mac(iface, reconf_msg.mac);
 141         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 142         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 143
 144         md5_ctx_t md5;
 145         uint8_t secretbytes[16];
 146         memcpy(secretbytes, assign->key, sizeof(secretbytes));
 147
 148         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 149                 secretbytes[i] ^= 0x36;
 150
 151         md5_begin(&md5);
 152         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 153         md5_hash(iov.iov_base, iov.iov_len, &md5);
 154         md5_end(reconf_msg.auth.key, &md5);
 155
 156         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 157                 secretbytes[i] ^= 0x36;
 158                 secretbytes[i] ^= 0x5c;
 159         }
 160
 161         md5_begin(&md5);
 162         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 163         md5_hash(reconf_msg.auth.key, 16, &md5);
 164         md5_end(reconf_msg.auth.key, &md5);
 165
 166         return odhcpd_send(socket_fd, &assign->peer, &iov, 1, iface);
 167 }
 168
 169
 170 void dhcpv6_write_statefile(void)
 171 {
 172         if (config.dhcp_statefile) {
 173                 time_t now = odhcpd_time(), wall_time = time(NULL);
 174                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 175                 if (fd < 0)
 176                         return;
 177
 178                 lockf(fd, F_LOCK, 0);
 179                 ftruncate(fd, 0);
 180
 181                 FILE *fp = fdopen(fd, "w");
 182                 if (!fp) {
 183                         close(fd);
 184                         return;
 185                 }
 186
 187                 struct interface *iface;
 188                 list_for_each_entry(iface, &interfaces, head) {
 189                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 190                                 continue;
 191
 192                         if (iface->dhcpv6 == RELAYD_SERVER) {
 193                                 struct dhcpv6_assignment *c;
 194                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 195                                         if (c->clid_len == 0)
 196                                                 continue;
 197
 198                                         char ipbuf[INET6_ADDRSTRLEN];
 199                                         char leasebuf[512];
 200                                         char duidbuf[264];
 201                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 202
 203                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 204                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 205                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 206                                                         (c->hostname ? c->hostname : "-"),
 207                                                         (unsigned)(c->valid_until > now ?
 208                                                                         (c->valid_until - now + wall_time) : 0),
 209                                                         c->assigned, (unsigned)c->length);
 210
 211                                         struct in6_addr addr;
 212                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 213                                                 if (iface->ia_addr[i].prefix > 64)
 214                                                         continue;
 215
 216                                                 addr = iface->ia_addr[i].addr;
 217                                                 if (c->length == 128)
 218                                                         addr.s6_addr32[3] = htonl(c->assigned);
 219                                                 else
 220                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 221                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 222
 223                                                 if (c->length == 128 && c->hostname && i == 0)
 224                                                         fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
 225
 226                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length);
 227                                         }
 228                                         leasebuf[l - 1] = '\n';
 229                                         fwrite(leasebuf, 1, l, fp);
 230                                 }
 231                         }
 232
 233                         if (iface->dhcpv4 == RELAYD_SERVER) {
 234                                 struct dhcpv4_assignment *c;
 235                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 236                                         char ipbuf[INET6_ADDRSTRLEN];
 237                                         char leasebuf[512];
 238                                         char duidbuf[16];
 239                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 240
 241                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 242                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 243                                                         iface->ifname, duidbuf,
 244                                                         (c->hostname ? c->hostname : "-"),
 245                                                         (unsigned)(c->valid_until > now ?
 246                                                                         (c->valid_until - now + wall_time) : 0),
 247                                                         c->addr);
 248
 249                                         struct in_addr addr = {htonl(c->addr)};
 250                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 251
 252                                         if (c->hostname[0])
 253                                                 fprintf(fp, "%s\t%s\n", ipbuf, c->hostname);
 254
 255                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 256                                         leasebuf[l - 1] = '\n';
 257                                         fwrite(leasebuf, 1, l, fp);
 258                                 }
 259                         }
 260                 }
 261
 262                 fclose(fp);
 263         }
 264
 265         if (config.dhcp_cb) {
 266                 char *argv[2] = {config.dhcp_cb, NULL};
 267                 if (!vfork()) {
 268                         execv(argv[0], argv);
 269                         _exit(128);
 270                 }
 271         }
 272 }
 273
 274
 275 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 276 {
 277         if (a->length > 64)
 278                 return;
 279
 280         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 281                 struct in6_addr prefix = iface->ia_addr[i].addr;
 282                 prefix.s6_addr32[1] |= htonl(a->assigned);
 283                 odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add);
 284         }
 285 }
 286
 287
 288 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 289 {
 290         struct dhcpv6_assignment *c;
 291         if (iface->ia_addr_len < 1)
 292                 return false;
 293
 294         // Try honoring the hint first
 295         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 296         if (assign->assigned) {
 297                 list_for_each_entry(c, &iface->ia_assignments, head) {
 298                         if (c->length == 128)
 299                                 continue;
 300
 301                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 302                                 list_add_tail(&assign->head, &c->head);
 303                                 apply_lease(iface, assign, true);
 304                                 return true;
 305                         }
 306
 307                         if (c->assigned != 0)
 308                                 current = (c->assigned + (1 << (64 - c->length)));
 309                 }
 310         }
 311
 312         // Fallback to a variable assignment
 313         current = 1;
 314         list_for_each_entry(c, &iface->ia_assignments, head) {
 315                 if (c->length == 128)
 316                         continue;
 317
 318                 current = (current + asize) & (~asize);
 319                 if (current + asize < c->assigned) {
 320                         assign->assigned = current;
 321                         list_add_tail(&assign->head, &c->head);
 322                         apply_lease(iface, assign, true);
 323                         return true;
 324                 }
 325
 326                 if (c->assigned != 0)
 327                         current = (c->assigned + (1 << (64 - c->length)));
 328         }
 329
 330         return false;
 331 }
 332
 333
 334 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 335 {
 336         if (iface->ia_addr_len < 1)
 337                 return false;
 338
 339         // Seed RNG with checksum of DUID
 340         uint32_t seed = 0;
 341         for (size_t i = 0; i < assign->clid_len; ++i)
 342                 seed += assign->clid_data[i];
 343         srand(seed);
 344
 345         // Try to assign up to 100x
 346         for (size_t i = 0; i < 100; ++i) {
 347                 uint32_t try;
 348                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 349
 350                 struct dhcpv6_assignment *c;
 351                 list_for_each_entry(c, &iface->ia_assignments, head) {
 352                         if (c->assigned > try || c->length != 128) {
 353                                 assign->assigned = try;
 354                                 list_add_tail(&assign->head, &c->head);
 355                                 return true;
 356                         } else if (c->assigned == try) {
 357                                 break;
 358                         }
 359                 }
 360         }
 361
 362         return false;
 363 }
 364
 365
 366 static int prefixcmp(const void *va, const void *vb)
 367 {
 368         const struct odhcpd_ipaddr *a = va, *b = vb;
 369         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 370         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 371         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 372 }
 373
 374
 375 static void update(struct interface *iface)
 376 {
 377         struct odhcpd_ipaddr addr[8];
 378         memset(addr, 0, sizeof(addr));
 379         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 380
 381         if (len < 0)
 382                 return;
 383
 384         qsort(addr, len, sizeof(*addr), prefixcmp);
 385
 386         time_t now = odhcpd_time();
 387         int minprefix = -1;
 388
 389         for (int i = 0; i < len; ++i) {
 390                 if (addr[i].prefix > minprefix)
 391                         minprefix = addr[i].prefix;
 392
 393                 addr[i].addr.s6_addr32[2] = 0;
 394                 addr[i].addr.s6_addr32[3] = 0;
 395
 396                 if (addr[i].preferred < UINT32_MAX - now)
 397                         addr[i].preferred += now;
 398
 399                 if (addr[i].valid < UINT32_MAX - now)
 400                         addr[i].valid += now;
 401         }
 402
 403         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 404         border->assigned = 1 << (64 - minprefix);
 405
 406         bool change = len != (int)iface->ia_addr_len;
 407         for (int i = 0; !change && i < len; ++i)
 408                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 409                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 410                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 411                                 (addr[i].valid > now + 7200) != (iface->ia_addr[i].valid > now + 7200))
 412                         change = true;
 413
 414         if (change) {
 415                 struct dhcpv6_assignment *c;
 416                 list_for_each_entry(c, &iface->ia_assignments, head)
 417                         if (c != border)
 418                                 apply_lease(iface, c, false);
 419         }
 420
 421         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 422         iface->ia_addr_len = len;
 423
 424         if (change) { // Addresses / prefixes have changed
 425                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 426                 struct dhcpv6_assignment *c, *d;
 427                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 428                         if (c->clid_len == 0 || c->valid_until < now)
 429                                 continue;
 430
 431                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 432                                 list_move(&c->head, &reassign);
 433                         else if (c != border)
 434                                 apply_lease(iface, c, true);
 435
 436                         if (c->accept_reconf && c->reconf_cnt == 0) {
 437                                 c->reconf_cnt = 1;
 438                                 c->reconf_sent = now;
 439                                 send_reconf(iface, c);
 440
 441                                 // Leave all other assignments of that client alone
 442                                 struct dhcpv6_assignment *a;
 443                                 list_for_each_entry(a, &iface->ia_assignments, head)
 444                                         if (a != c && a->clid_len == c->clid_len &&
 445                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 446                                                 c->reconf_cnt = INT_MAX;
 447                         }
 448                 }
 449
 450                 while (!list_empty(&reassign)) {
 451                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 452                         list_del(&c->head);
 453                         if (!assign_pd(iface, c)) {
 454                                 c->assigned = 0;
 455                                 list_add(&c->head, &iface->ia_assignments);
 456                         }
 457                 }
 458
 459                 dhcpv6_write_statefile();
 460         }
 461 }
 462
 463
 464 static void reconf_timer(struct uloop_timeout *event)
 465 {
 466         time_t now = odhcpd_time();
 467         struct interface *iface;
 468         list_for_each_entry(iface, &interfaces, head) {
 469                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 470                         continue;
 471
 472                 struct dhcpv6_assignment *a, *n;
 473                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 474                         if (a->valid_until < now) {
 475                                 if ((a->length < 128 && a->clid_len > 0) ||
 476                                                 (a->length == 128 && a->clid_len == 0)) {
 477                                         list_del(&a->head);
 478                                         free(a->hostname);
 479                                         free(a);
 480                                 }
 481                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 482                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 483                                 ++a->reconf_cnt;
 484                                 a->reconf_sent = now;
 485                                 send_reconf(iface, a);
 486                         }
 487                 }
 488
 489                 if (iface->ia_reconf) {
 490                         update(iface);
 491                         iface->ia_reconf = false;
 492                 }
 493         }
 494
 495         uloop_timeout_set(event, 2000);
 496 }
 497
 498
 499 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 500                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 501                 struct interface *iface, bool request)
 502 {
 503         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 504                 return 0;
 505
 506         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 507         size_t datalen = sizeof(out);
 508         time_t now = odhcpd_time();
 509
 510         if (status) {
 511                 struct __attribute__((packed)) {
 512                         uint16_t type;
 513                         uint16_t len;
 514                         uint16_t value;
 515                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 516                                 htons(status)};
 517
 518                 memcpy(buf + datalen, &stat, sizeof(stat));
 519                 datalen += sizeof(stat);
 520         } else {
 521                 if (a) {
 522                         uint32_t pref = 3600;
 523                         uint32_t valid = 3600;
 524                         bool have_non_ula = false;
 525                         for (size_t i = 0; i < iface->ia_addr_len; ++i)
 526                                 if ((iface->ia_addr[i].addr.s6_addr[0] & 0xfe) != 0xfc)
 527                                         have_non_ula = true;
 528
 529                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 530                                 uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
 531                                 uint32_t prefix_valid = iface->ia_addr[i].valid - now;
 532
 533                                 if (iface->ia_addr[i].prefix > 64 ||
 534                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 535                                         continue;
 536
 537                                 // ULA-deprecation compatibility workaround
 538                                 if ((iface->ia_addr[i].addr.s6_addr[0] & 0xfe) == 0xfc &&
 539                                                 a->length == 128 && have_non_ula &&
 540                                                 iface->deprecate_ula_if_public_avail)
 541                                         continue;
 542
 543                                 if (prefix_pref > 86400)
 544                                         prefix_pref = 86400;
 545
 546                                 if (prefix_valid > 86400)
 547                                         prefix_valid = 86400;
 548
 549                                 if (a->length < 128) {
 550                                         struct dhcpv6_ia_prefix p = {
 551                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 552                                                 .len = htons(sizeof(p) - 4),
 553                                                 .preferred = htonl(prefix_pref),
 554                                                 .valid = htonl(prefix_valid),
 555                                                 .prefix = a->length,
 556                                                 .addr = iface->ia_addr[i].addr
 557                                         };
 558                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 559
 560                                         if (datalen + sizeof(p) > buflen || a->assigned == 0)
 561                                                 continue;
 562
 563                                         memcpy(buf + datalen, &p, sizeof(p));
 564                                         datalen += sizeof(p);
 565                                 } else {
 566                                         struct dhcpv6_ia_addr n = {
 567                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 568                                                 .len = htons(sizeof(n) - 4),
 569                                                 .addr = iface->ia_addr[i].addr,
 570                                                 .preferred = htonl(prefix_pref),
 571                                                 .valid = htonl(prefix_valid)
 572                                         };
 573                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 574
 575                                         if (datalen + sizeof(n) > buflen || a->assigned == 0)
 576                                                 continue;
 577
 578                                         memcpy(buf + datalen, &n, sizeof(n));
 579                                         datalen += sizeof(n);
 580                                 }
 581
 582                                 // Calculate T1 / T2 based on non-deprecated addresses
 583                                 if (prefix_pref > 0) {
 584                                         if (prefix_pref < pref)
 585                                                 pref = prefix_pref;
 586
 587                                         if (prefix_valid < valid)
 588                                                 valid = prefix_valid;
 589                                 }
 590                         }
 591
 592                         a->valid_until = valid + now;
 593                         out.t1 = htonl(pref * 5 / 10);
 594                         out.t2 = htonl(pref * 8 / 10);
 595
 596                         if (!out.t1)
 597                                 out.t1 = htonl(1);
 598
 599                         if (!out.t2)
 600                                 out.t2 = htonl(1);
 601                 }
 602
 603                 if (!request) {
 604                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 605                         uint16_t otype, olen;
 606                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 607                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 608                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 609                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 610                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 611                                         continue;
 612
 613                                 bool found = false;
 614                                 if (a) {
 615                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 616                                                 if (iface->ia_addr[i].prefix > 64 ||
 617                                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 618                                                         continue;
 619
 620                                                 struct in6_addr addr = iface->ia_addr[i].addr;
 621                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 622                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 623
 624                                                         if (IN6_ARE_ADDR_EQUAL(&p->addr, &addr) &&
 625                                                                         p->prefix == a->length)
 626                                                                 found = true;
 627                                                 } else {
 628                                                         addr.s6_addr32[3] = htonl(a->assigned);
 629
 630                                                         if (IN6_ARE_ADDR_EQUAL(&n->addr, &addr))
 631                                                                 found = true;
 632                                                 }
 633                                         }
 634                                 }
 635
 636                                 if (!found) {
 637                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 638                                                 struct dhcpv6_ia_prefix inv = {
 639                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 640                                                         .len = htons(sizeof(inv) - 4),
 641                                                         .preferred = 0,
 642                                                         .valid = 0,
 643                                                         .prefix = p->prefix,
 644                                                         .addr = p->addr
 645                                                 };
 646
 647                                                 if (datalen + sizeof(inv) > buflen)
 648                                                         continue;
 649
 650                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 651                                                 datalen += sizeof(inv);
 652                                         } else {
 653                                                 struct dhcpv6_ia_addr inv = {
 654                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 655                                                         .len = htons(sizeof(inv) - 4),
 656                                                         .addr = n->addr,
 657                                                         .preferred = 0,
 658                                                         .valid = 0
 659                                                 };
 660
 661                                                 if (datalen + sizeof(inv) > buflen)
 662                                                         continue;
 663
 664                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 665                                                 datalen += sizeof(inv);
 666                                         }
 667                                 }
 668                         }
 669                 }
 670         }
 671
 672         out.len = htons(datalen - 4);
 673         memcpy(buf, &out, sizeof(out));
 674         return datalen;
 675 }
 676
 677
 678 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 679                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 680 {
 681         time_t now = odhcpd_time();
 682         size_t response_len = 0;
 683         const struct dhcpv6_client_header *hdr = data;
 684         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 685         uint16_t otype, olen;
 686
 687         // Find and parse client-id and hostname
 688         bool accept_reconf = false;
 689         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 690         char hostname[256];
 691         size_t hostname_len = 0;
 692         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 693                 if (otype == DHCPV6_OPT_CLIENTID) {
 694                         clid_data = odata;
 695                         clid_len = olen;
 696
 697                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 698                                 memcpy(mac, &odata[8], sizeof(mac));
 699                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 700                                 memcpy(mac, &odata[4], sizeof(mac));
 701                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 702                         uint8_t fqdn_buf[256];
 703                         memcpy(fqdn_buf, odata, olen);
 704                         fqdn_buf[olen++] = 0;
 705
 706                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 707                                 hostname_len = strcspn(hostname, ".");
 708                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 709                         accept_reconf = true;
 710                 }
 711         }
 712
 713         if (!clid_data || !clid_len || clid_len > 130)
 714                 goto out;
 715
 716         update(iface);
 717         bool update_state = false;
 718
 719         struct dhcpv6_assignment *first = NULL;
 720         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 721                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 722                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 723                 if (!is_pd && !is_na)
 724                         continue;
 725
 726                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 727                 size_t ia_response_len = 0;
 728                 uint8_t reqlen = (is_pd) ? 62 : 128;
 729                 uint32_t reqhint = 0;
 730
 731                 // Parse request hint for IA-PD
 732                 if (is_pd) {
 733                         uint8_t *sdata;
 734                         uint16_t stype, slen;
 735                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 736                                 if (stype == DHCPV6_OPT_IA_PREFIX && slen >= sizeof(struct dhcpv6_ia_prefix) - 4) {
 737                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 738                                         if (p->prefix) {
 739                                                 reqlen = p->prefix;
 740                                                 reqhint = ntohl(p->addr.s6_addr32[1]);
 741                                                 if (reqlen > 32 && reqlen <= 64)
 742                                                         reqhint &= (1U << (64 - reqlen)) - 1;
 743                                         }
 744                                         break;
 745                                 }
 746                         }
 747
 748                         if (reqlen > 64)
 749                                 reqlen = 64;
 750                 }
 751
 752                 // Find assignment
 753                 struct dhcpv6_assignment *c, *a = NULL;
 754                 list_for_each_entry(c, &iface->ia_assignments, head) {
 755                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
 756                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
 757                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
 758                                         (c->iaid == ia->iaid || c->valid_until < now) &&
 759                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
 760                                 a = c;
 761
 762                                 // Reset state
 763                                 apply_lease(iface, a, false);
 764                                 memcpy(a->clid_data, clid_data, clid_len);
 765                                 a->clid_len = clid_len;
 766                                 a->iaid = ia->iaid;
 767                                 a->peer = *addr;
 768                                 a->reconf_cnt = 0;
 769                                 a->reconf_sent = 0;
 770                                 break;
 771                         }
 772                 }
 773
 774                 // Generic message handling
 775                 uint16_t status = DHCPV6_STATUS_OK;
 776                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
 777                         bool assigned = !!a;
 778
 779                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
 780                                 a = calloc(1, sizeof(*a) + clid_len);
 781                                 a->clid_len = clid_len;
 782                                 a->iaid = ia->iaid;
 783                                 a->length = reqlen;
 784                                 a->peer = *addr;
 785                                 a->assigned = reqhint;
 786                                 if (first)
 787                                         memcpy(a->key, first->key, sizeof(a->key));
 788                                 else
 789                                         odhcpd_urandom(a->key, sizeof(a->key));
 790                                 memcpy(a->clid_data, clid_data, clid_len);
 791
 792                                 if (is_pd)
 793                                         while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64);
 794                                 else
 795                                         assigned = assign_na(iface, a);
 796                         }
 797
 798                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
 799                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
 800                         } else if (assigned && !first) { //
 801                                 size_t handshake_len = 4;
 802                                 buf[0] = 0;
 803                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
 804                                 buf[2] = 0;
 805                                 buf[3] = 0;
 806
 807                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
 808                                         struct dhcpv6_auth_reconfigure auth = {
 809                                                 htons(DHCPV6_OPT_AUTH),
 810                                                 htons(sizeof(auth) - 4),
 811                                                 3, 1, 0,
 812                                                 {htonl(time(NULL)), htonl(++serial)},
 813                                                 1,
 814                                                 {0}
 815                                         };
 816                                         memcpy(auth.key, a->key, sizeof(a->key));
 817                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
 818                                         handshake_len += sizeof(auth);
 819                                 }
 820
 821                                 buf += handshake_len;
 822                                 buflen -= handshake_len;
 823                                 response_len += handshake_len;
 824
 825                                 first = a;
 826                         }
 827
 828                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
 829
 830                         // Was only a solicitation: mark binding for removal
 831                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
 832                                 a->valid_until = 0;
 833                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
 834                                 if (hostname_len > 0) {
 835                                         a->hostname = realloc(a->hostname, hostname_len + 1);
 836                                         memcpy(a->hostname, hostname, hostname_len);
 837                                         a->hostname[hostname_len] = 0;
 838                                 }
 839                                 a->accept_reconf = accept_reconf;
 840                                 apply_lease(iface, a, true);
 841                                 update_state = true;
 842                         } else if (!assigned && a) { // Cleanup failed assignment
 843                                 free(a->hostname);
 844                                 free(a);
 845                         }
 846                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
 847                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
 848                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
 849                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
 850                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
 851                                 status = DHCPV6_STATUS_NOBINDING;
 852                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
 853                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
 854                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
 855                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
 856                                 if (a)
 857                                         apply_lease(iface, a, true);
 858                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
 859                                 a->valid_until = 0;
 860                                 apply_lease(iface, a, false);
 861                                 update_state = true;
 862                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
 863                                 a->clid_len = 0;
 864                                 a->valid_until = now + 3600; // Block address for 1h
 865                                 update_state = true;
 866                         }
 867                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
 868                         // Always send NOTONLINK for CONFIRM so that clients restart connection
 869                         status = DHCPV6_STATUS_NOTONLINK;
 870                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
 871                 }
 872
 873                 buf += ia_response_len;
 874                 buflen -= ia_response_len;
 875                 response_len += ia_response_len;
 876         }
 877
 878         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
 879                 buf[0] = 0;
 880                 buf[1] = DHCPV6_OPT_STATUS;
 881                 buf[2] = 0;
 882                 buf[3] = 2;
 883                 buf[4] = 0;
 884                 buf[5] = DHCPV6_STATUS_OK;
 885                 response_len += 6;
 886         }
 887
 888         if (update_state)
 889                 dhcpv6_write_statefile();
 890
 891 out:
 892         return response_len;
 893 }