src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19
  20 #include <time.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <alloca.h>
  24 #include <resolv.h>
  25 #include <limits.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <arpa/inet.h>
  29 #include <sys/timerfd.h>
  30
  31
  32 static void update(struct interface *iface);
  33 static void reconf_timer(struct uloop_timeout *event);
  34 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  35 static uint32_t serial = 0;
  36 static uint8_t statemd5[16];
  37
  38
  39 int dhcpv6_ia_init(void)
  40 {
  41         uloop_timeout_set(&reconf_event, 2000);
  42         return 0;
  43 }
  44
  45
  46 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  47 {
  48         if (!enable && iface->ia_assignments.next) {
  49                 struct dhcpv6_assignment *c;
  50                 while (!list_empty(&iface->ia_assignments)) {
  51                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  52                         list_del(&c->head);
  53                         free(c->hostname);
  54                         free(c->classes);
  55                         free(c);
  56                 }
  57         }
  58
  59         if (iface->dhcpv6 == RELAYD_SERVER) {
  60                 if (!iface->ia_assignments.next)
  61                         INIT_LIST_HEAD(&iface->ia_assignments);
  62
  63                 if (list_empty(&iface->ia_assignments)) {
  64                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  65                         if (!border) {
  66                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  67                                 return -1;
  68                         }
  69
  70                         border->length = 64;
  71                         list_add(&border->head, &iface->ia_assignments);
  72                 }
  73
  74                 update(iface);
  75
  76                 // Parse static entries
  77                 struct lease *lease;
  78                 list_for_each_entry(lease, &leases, head) {
  79                         // Construct entry
  80                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  81                         if (!a) {
  82                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  83                                         iface->ifname);
  84                                 return -1;
  85                         }
  86
  87                         a->clid_len = lease->duid_len;
  88                         a->length = 128;
  89                         if (lease->hostid) {
  90                                 a->assigned = lease->hostid;
  91                         } else {
  92                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  93                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
  94                         }
  95                         odhcpd_urandom(a->key, sizeof(a->key));
  96                         memcpy(a->clid_data, lease->duid, a->clid_len);
  97                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
  98
  99                         // Assign to all interfaces
 100                         struct dhcpv6_assignment *c;
 101                         list_for_each_entry(c, &iface->ia_assignments, head) {
 102                                 if (c->length != 128 || c->assigned > a->assigned) {
 103                                         list_add_tail(&a->head, &c->head);
 104                                         break;
 105                                 } else if (c->assigned == a->assigned) {
 106                                         // Already an assignment with that number
 107                                         break;
 108                                 }
 109                         }
 110
 111                         if (a->head.next) {
 112                                 if (lease->hostname[0]) {
 113                                         free(a->hostname);
 114                                         a->hostname = strdup(lease->hostname);
 115                                 }
 116                         } else {
 117                                 free(a->classes);
 118                                 free(a->hostname);
 119                                 free(a);
 120                         }
 121                 }
 122         }
 123         return 0;
 124 }
 125
 126
 127 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 128 {
 129         struct {
 130                 struct dhcpv6_client_header hdr;
 131                 uint16_t srvid_type;
 132                 uint16_t srvid_len;
 133                 uint16_t duid_type;
 134                 uint16_t hardware_type;
 135                 uint8_t mac[6];
 136                 uint16_t msg_type;
 137                 uint16_t msg_len;
 138                 uint8_t msg_id;
 139                 struct dhcpv6_auth_reconfigure auth;
 140                 uint16_t clid_type;
 141                 uint16_t clid_len;
 142                 uint8_t clid_data[128];
 143         } __attribute__((packed)) reconf_msg = {
 144                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 145                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 146                 .srvid_len = htons(10),
 147                 .duid_type = htons(3),
 148                 .hardware_type = htons(1),
 149                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 150                 .msg_len = htons(1),
 151                 .msg_id = DHCPV6_MSG_RENEW,
 152                 .auth = {htons(DHCPV6_OPT_AUTH),
 153                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 154                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 155                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 156                 .clid_len = htons(assign->clid_len),
 157                 .clid_data = {0},
 158         };
 159
 160         odhcpd_get_mac(iface, reconf_msg.mac);
 161         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 162         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 163
 164         md5_ctx_t md5;
 165         uint8_t secretbytes[64];
 166         memset(secretbytes, 0, sizeof(secretbytes));
 167         memcpy(secretbytes, assign->key, sizeof(assign->key));
 168
 169         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 170                 secretbytes[i] ^= 0x36;
 171
 172         md5_begin(&md5);
 173         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 174         md5_hash(iov.iov_base, iov.iov_len, &md5);
 175         md5_end(reconf_msg.auth.key, &md5);
 176
 177         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 178                 secretbytes[i] ^= 0x36;
 179                 secretbytes[i] ^= 0x5c;
 180         }
 181
 182         md5_begin(&md5);
 183         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 184         md5_hash(reconf_msg.auth.key, 16, &md5);
 185         md5_end(reconf_msg.auth.key, &md5);
 186
 187         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 188 }
 189
 190
 191 void dhcpv6_write_statefile(void)
 192 {
 193         md5_ctx_t md5;
 194         md5_begin(&md5);
 195
 196         if (config.dhcp_statefile) {
 197                 time_t now = odhcpd_time(), wall_time = time(NULL);
 198                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 199                 if (fd < 0)
 200                         return;
 201
 202                 lockf(fd, F_LOCK, 0);
 203                 ftruncate(fd, 0);
 204
 205                 FILE *fp = fdopen(fd, "w");
 206                 if (!fp) {
 207                         close(fd);
 208                         return;
 209                 }
 210
 211                 struct interface *iface;
 212                 list_for_each_entry(iface, &interfaces, head) {
 213                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 214                                 continue;
 215
 216                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 217                                 struct dhcpv6_assignment *c;
 218                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 219                                         if (c->clid_len == 0)
 220                                                 continue;
 221
 222                                         char ipbuf[INET6_ADDRSTRLEN];
 223                                         char leasebuf[512];
 224                                         char duidbuf[264];
 225                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 226
 227                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 228                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 229                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 230                                                         (c->hostname ? c->hostname : "-"),
 231                                                         (unsigned)(c->valid_until > now ?
 232                                                                         (c->valid_until - now + wall_time) : 0),
 233                                                         c->assigned, (unsigned)c->length);
 234
 235                                         struct in6_addr addr;
 236                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 237                                                 if (iface->ia_addr[i].prefix > 96)
 238                                                         continue;
 239
 240                                                 addr = iface->ia_addr[i].addr;
 241                                                 if (c->length == 128)
 242                                                         addr.s6_addr32[3] = htonl(c->assigned);
 243                                                 else
 244                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 245                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 246
 247                                                 if (c->length == 128 && c->hostname && i == 0) {
 248                                                         fputs(ipbuf, fp);
 249
 250                                                         char b[256];
 251                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 252                                                                         iface->search, b, sizeof(b)) > 0)
 253                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 254
 255                                                         fprintf(fp, "\t%s\n", c->hostname);
 256                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 257                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 258                                                 }
 259
 260                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length);
 261                                         }
 262                                         leasebuf[l - 1] = '\n';
 263                                         fwrite(leasebuf, 1, l, fp);
 264                                 }
 265                         }
 266
 267                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 268                                 struct dhcpv4_assignment *c;
 269                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 270                                         char ipbuf[INET6_ADDRSTRLEN];
 271                                         char leasebuf[512];
 272                                         char duidbuf[16];
 273                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 274
 275                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 276                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 277                                                         iface->ifname, duidbuf,
 278                                                         (c->hostname ? c->hostname : "-"),
 279                                                         (unsigned)(c->valid_until > now ?
 280                                                                         (c->valid_until - now + wall_time) : 0),
 281                                                         c->addr);
 282
 283                                         struct in_addr addr = {htonl(c->addr)};
 284                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 285
 286                                         if (c->hostname[0]) {
 287                                                 fputs(ipbuf, fp);
 288
 289                                                 char b[256];
 290                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 291                                                                 iface->search, b, sizeof(b)) > 0)
 292                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 293
 294                                                 fprintf(fp, "\t%s\n", c->hostname);
 295                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 296                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 297                                         }
 298
 299                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 300                                         leasebuf[l - 1] = '\n';
 301                                         fwrite(leasebuf, 1, l, fp);
 302                                 }
 303                         }
 304                 }
 305
 306                 fclose(fp);
 307         }
 308
 309         uint8_t newmd5[16];
 310         md5_end(newmd5, &md5);
 311
 312         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 313                 memcpy(statemd5, newmd5, sizeof(statemd5));
 314                 char *argv[2] = {config.dhcp_cb, NULL};
 315                 if (!vfork()) {
 316                         execv(argv[0], argv);
 317                         _exit(128);
 318                 }
 319         }
 320 }
 321
 322
 323 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 324 {
 325         if (a->length > 64)
 326                 return;
 327
 328         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 329                 struct in6_addr prefix = iface->ia_addr[i].addr;
 330                 prefix.s6_addr32[1] |= htonl(a->assigned);
 331                 odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add);
 332         }
 333 }
 334
 335
 336 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 337 {
 338         struct dhcpv6_assignment *c;
 339         if (iface->ia_addr_len < 1)
 340                 return false;
 341
 342         // Try honoring the hint first
 343         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 344         if (assign->assigned) {
 345                 list_for_each_entry(c, &iface->ia_assignments, head) {
 346                         if (c->length == 128)
 347                                 continue;
 348
 349                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 350                                 list_add_tail(&assign->head, &c->head);
 351                                 apply_lease(iface, assign, true);
 352                                 return true;
 353                         }
 354
 355                         if (c->assigned != 0)
 356                                 current = (c->assigned + (1 << (64 - c->length)));
 357                 }
 358         }
 359
 360         // Fallback to a variable assignment
 361         current = 1;
 362         list_for_each_entry(c, &iface->ia_assignments, head) {
 363                 if (c->length == 128)
 364                         continue;
 365
 366                 current = (current + asize) & (~asize);
 367                 if (current + asize < c->assigned) {
 368                         assign->assigned = current;
 369                         list_add_tail(&assign->head, &c->head);
 370                         apply_lease(iface, assign, true);
 371                         return true;
 372                 }
 373
 374                 if (c->assigned != 0)
 375                         current = (c->assigned + (1 << (64 - c->length)));
 376         }
 377
 378         return false;
 379 }
 380
 381
 382 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 383 {
 384         bool match = false;
 385         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 386                 if (!iface->ia_addr[i].has_class) {
 387                         match = true;
 388                         continue;
 389                 } else if (assign->classes_cnt) {
 390                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 391                                 if (assign->classes[j] == iface->ia_addr[i].class)
 392                                         match = true;
 393                 } else if (assign->all_class) {
 394                         match = true;
 395                 }
 396         }
 397
 398         if (!match)
 399                 return false;
 400
 401         // Seed RNG with checksum of DUID
 402         uint32_t seed = 0;
 403         for (size_t i = 0; i < assign->clid_len; ++i)
 404                 seed += assign->clid_data[i];
 405         srand(seed);
 406
 407         // Try to assign up to 100x
 408         for (size_t i = 0; i < 100; ++i) {
 409                 uint32_t try;
 410                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 411
 412                 struct dhcpv6_assignment *c;
 413                 list_for_each_entry(c, &iface->ia_assignments, head) {
 414                         if (c->assigned > try || c->length != 128) {
 415                                 assign->assigned = try;
 416                                 list_add_tail(&assign->head, &c->head);
 417                                 return true;
 418                         } else if (c->assigned == try) {
 419                                 break;
 420                         }
 421                 }
 422         }
 423
 424         return false;
 425 }
 426
 427
 428 static int prefixcmp(const void *va, const void *vb)
 429 {
 430         const struct odhcpd_ipaddr *a = va, *b = vb;
 431         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 432         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 433         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 434 }
 435
 436
 437 static void update(struct interface *iface)
 438 {
 439         struct odhcpd_ipaddr addr[8];
 440         memset(addr, 0, sizeof(addr));
 441         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 442
 443         if (len < 0)
 444                 return;
 445
 446         qsort(addr, len, sizeof(*addr), prefixcmp);
 447
 448         time_t now = odhcpd_time();
 449         int minprefix = -1;
 450
 451         for (int i = 0; i < len; ++i) {
 452                 if (addr[i].prefix > minprefix)
 453                         minprefix = addr[i].prefix;
 454
 455                 addr[i].addr.s6_addr32[3] = 0;
 456
 457                 if (addr[i].preferred < UINT32_MAX - now)
 458                         addr[i].preferred += now;
 459
 460                 if (addr[i].valid < UINT32_MAX - now)
 461                         addr[i].valid += now;
 462         }
 463
 464         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 465         border->assigned = 1 << (64 - minprefix);
 466
 467         bool change = len != (int)iface->ia_addr_len;
 468         for (int i = 0; !change && i < len; ++i)
 469                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 470                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 471                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 472                                 (addr[i].valid > (uint32_t)now + 7200) !=
 473                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 474                         change = true;
 475
 476         if (change) {
 477                 struct dhcpv6_assignment *c;
 478                 list_for_each_entry(c, &iface->ia_assignments, head)
 479                         if (c != border)
 480                                 apply_lease(iface, c, false);
 481         }
 482
 483         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 484         iface->ia_addr_len = len;
 485
 486         if (change) { // Addresses / prefixes have changed
 487                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 488                 struct dhcpv6_assignment *c, *d;
 489                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 490                         if (c->clid_len == 0 || c->valid_until < now)
 491                                 continue;
 492
 493                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 494                                 list_move(&c->head, &reassign);
 495                         else if (c != border)
 496                                 apply_lease(iface, c, true);
 497
 498                         if (c->accept_reconf && c->reconf_cnt == 0) {
 499                                 c->reconf_cnt = 1;
 500                                 c->reconf_sent = now;
 501                                 send_reconf(iface, c);
 502
 503                                 // Leave all other assignments of that client alone
 504                                 struct dhcpv6_assignment *a;
 505                                 list_for_each_entry(a, &iface->ia_assignments, head)
 506                                         if (a != c && a->clid_len == c->clid_len &&
 507                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 508                                                 c->reconf_cnt = INT_MAX;
 509                         }
 510                 }
 511
 512                 while (!list_empty(&reassign)) {
 513                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 514                         list_del(&c->head);
 515                         if (!assign_pd(iface, c)) {
 516                                 c->assigned = 0;
 517                                 list_add(&c->head, &iface->ia_assignments);
 518                         }
 519                 }
 520
 521                 dhcpv6_write_statefile();
 522         }
 523 }
 524
 525
 526 static void reconf_timer(struct uloop_timeout *event)
 527 {
 528         time_t now = odhcpd_time();
 529         struct interface *iface;
 530         list_for_each_entry(iface, &interfaces, head) {
 531                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 532                         continue;
 533
 534                 struct dhcpv6_assignment *a, *n;
 535                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 536                         if (a->valid_until < now) {
 537                                 if ((a->length < 128 && a->clid_len > 0) ||
 538                                                 (a->length == 128 && a->clid_len == 0)) {
 539                                         list_del(&a->head);
 540                                         free(a->classes);
 541                                         free(a->hostname);
 542                                         free(a);
 543                                 }
 544                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 545                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 546                                 ++a->reconf_cnt;
 547                                 a->reconf_sent = now;
 548                                 send_reconf(iface, a);
 549                         }
 550                 }
 551
 552                 if (iface->ia_reconf) {
 553                         update(iface);
 554                         iface->ia_reconf = false;
 555                 }
 556         }
 557
 558         uloop_timeout_set(event, 2000);
 559 }
 560
 561
 562 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 563                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 564                 struct interface *iface, bool request)
 565 {
 566         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 567                 return 0;
 568
 569         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 570         size_t datalen = sizeof(out);
 571         time_t now = odhcpd_time();
 572
 573         if (status) {
 574                 struct __attribute__((packed)) {
 575                         uint16_t type;
 576                         uint16_t len;
 577                         uint16_t value;
 578                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 579                                 htons(status)};
 580
 581                 memcpy(buf + datalen, &stat, sizeof(stat));
 582                 datalen += sizeof(stat);
 583         } else {
 584                 if (a) {
 585                         uint32_t pref = 3600;
 586                         uint32_t valid = 3600;
 587
 588                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 589                                 bool match = true;
 590                                 if (iface->ia_addr[i].has_class) {
 591                                         match = false;
 592                                         if (a->classes_cnt) {
 593                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 594                                                         if (a->classes[j] == iface->ia_addr[i].class)
 595                                                                 match = true;
 596                                         } else if (a->all_class) {
 597                                                 match = true;
 598                                         }
 599                                 }
 600
 601                                 if (!match)
 602                                         continue;
 603
 604                                 uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
 605                                 uint32_t prefix_valid = iface->ia_addr[i].valid - now;
 606
 607                                 if (iface->ia_addr[i].prefix > 96 ||
 608                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 609                                         continue;
 610
 611                                 if (prefix_pref > 86400)
 612                                         prefix_pref = 86400;
 613
 614                                 if (prefix_valid > 86400)
 615                                         prefix_valid = 86400;
 616
 617 #ifdef DHCPV6_OPT_PREFIX_CLASS
 618                                 struct {
 619                                         uint16_t code;
 620                                         uint16_t length;
 621                                         uint16_t class;
 622                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 623                                         htons(2), htons(iface->ia_addr[i].class)};
 624 #endif
 625
 626                                 if (a->length < 128) {
 627                                         struct dhcpv6_ia_prefix p = {
 628                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 629                                                 .len = htons(sizeof(p) - 4),
 630                                                 .preferred = htonl(prefix_pref),
 631                                                 .valid = htonl(prefix_valid),
 632                                                 .prefix = a->length,
 633                                                 .addr = iface->ia_addr[i].addr
 634                                         };
 635                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 636                                         size_t entrlen = sizeof(p) - 4;
 637
 638 #ifdef DHCPV6_OPT_PREFIX_CLASS
 639                                         if (iface->ia_addr[i].has_class) {
 640                                                 entrlen += sizeof(pclass);
 641                                                 p.len = htons(entrlen);
 642                                         }
 643 #endif
 644
 645                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 646                                                 continue;
 647
 648                                         memcpy(buf + datalen, &p, sizeof(p));
 649 #ifdef DHCPV6_OPT_PREFIX_CLASS
 650                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 651 #endif
 652                                         datalen += entrlen + 4;
 653                                 } else {
 654                                         struct dhcpv6_ia_addr n = {
 655                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 656                                                 .len = htons(sizeof(n) - 4),
 657                                                 .addr = iface->ia_addr[i].addr,
 658                                                 .preferred = htonl(prefix_pref),
 659                                                 .valid = htonl(prefix_valid)
 660                                         };
 661                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 662                                         size_t entrlen = sizeof(n) - 4;
 663
 664 #ifdef DHCPV6_OPT_PREFIX_CLASS
 665                                         if (iface->ia_addr[i].has_class) {
 666                                                 entrlen += sizeof(pclass);
 667                                                 n.len = htons(entrlen);
 668                                         }
 669 #endif
 670
 671                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 672                                                 continue;
 673
 674                                         memcpy(buf + datalen, &n, sizeof(n));
 675 #ifdef DHCPV6_OPT_PREFIX_CLASS
 676                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 677 #endif
 678                                         datalen += entrlen + 4;
 679                                 }
 680
 681                                 // Calculate T1 / T2 based on non-deprecated addresses
 682                                 if (prefix_pref > 0) {
 683                                         if (prefix_pref < pref)
 684                                                 pref = prefix_pref;
 685
 686                                         if (prefix_valid < valid)
 687                                                 valid = prefix_valid;
 688                                 }
 689                         }
 690
 691                         a->valid_until = valid + now;
 692                         out.t1 = htonl(pref * 5 / 10);
 693                         out.t2 = htonl(pref * 8 / 10);
 694
 695                         if (!out.t1)
 696                                 out.t1 = htonl(1);
 697
 698                         if (!out.t2)
 699                                 out.t2 = htonl(1);
 700                 }
 701
 702                 if (!request) {
 703                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 704                         uint16_t otype, olen;
 705                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 706                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 707                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 708                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 709                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 710                                         continue;
 711
 712                                 bool found = false;
 713                                 if (a) {
 714                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 715                                                 if (iface->ia_addr[i].prefix > 96 ||
 716                                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 717                                                         continue;
 718
 719                                                 struct in6_addr addr = iface->ia_addr[i].addr;
 720                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 721                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 722
 723                                                         if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
 724                                                                         p->prefix == a->length)
 725                                                                 found = true;
 726                                                 } else {
 727                                                         addr.s6_addr32[3] = htonl(a->assigned);
 728
 729                                                         if (!memcmp(&n->addr, &addr, sizeof(addr)))
 730                                                                 found = true;
 731                                                 }
 732                                         }
 733                                 }
 734
 735                                 if (!found) {
 736                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 737                                                 struct dhcpv6_ia_prefix inv = {
 738                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 739                                                         .len = htons(sizeof(inv) - 4),
 740                                                         .preferred = 0,
 741                                                         .valid = 0,
 742                                                         .prefix = p->prefix,
 743                                                         .addr = p->addr
 744                                                 };
 745
 746                                                 if (datalen + sizeof(inv) > buflen)
 747                                                         continue;
 748
 749                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 750                                                 datalen += sizeof(inv);
 751                                         } else {
 752                                                 struct dhcpv6_ia_addr inv = {
 753                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 754                                                         .len = htons(sizeof(inv) - 4),
 755                                                         .addr = n->addr,
 756                                                         .preferred = 0,
 757                                                         .valid = 0
 758                                                 };
 759
 760                                                 if (datalen + sizeof(inv) > buflen)
 761                                                         continue;
 762
 763                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 764                                                 datalen += sizeof(inv);
 765                                         }
 766                                 }
 767                         }
 768                 }
 769         }
 770
 771         out.len = htons(datalen - 4);
 772         memcpy(buf, &out, sizeof(out));
 773         return datalen;
 774 }
 775
 776
 777 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 778                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 779 {
 780         time_t now = odhcpd_time();
 781         size_t response_len = 0;
 782         const struct dhcpv6_client_header *hdr = data;
 783         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 784         uint16_t otype, olen;
 785
 786         // Find and parse client-id and hostname
 787         bool accept_reconf = false;
 788         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 789         char hostname[256];
 790         size_t hostname_len = 0;
 791         bool class_oro = false;
 792         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 793                 if (otype == DHCPV6_OPT_CLIENTID) {
 794                         clid_data = odata;
 795                         clid_len = olen;
 796
 797                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 798                                 memcpy(mac, &odata[8], sizeof(mac));
 799                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 800                                 memcpy(mac, &odata[4], sizeof(mac));
 801                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 802                         uint8_t fqdn_buf[256];
 803                         memcpy(fqdn_buf, odata, olen);
 804                         fqdn_buf[olen++] = 0;
 805
 806                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 807                                 hostname_len = strcspn(hostname, ".");
 808                 } else if (otype == DHCPV6_OPT_ORO) {
 809 #ifdef DHCPV6_OPT_PREFIX_CLASS
 810                         for (size_t i = 0; i + 1 < olen; i += 2) {
 811                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 812                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 813                                         class_oro = true;
 814                         }
 815 #endif
 816                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 817                         accept_reconf = true;
 818                 }
 819         }
 820
 821         if (!clid_data || !clid_len || clid_len > 130)
 822                 goto out;
 823
 824         update(iface);
 825         bool update_state = false;
 826
 827         struct dhcpv6_assignment *first = NULL;
 828         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 829                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 830                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 831                 if (!is_pd && !is_na)
 832                         continue;
 833
 834                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 835                 size_t ia_response_len = 0;
 836                 uint8_t reqlen = (is_pd) ? 62 : 128;
 837                 uint32_t reqhint = 0;
 838
 839                 const uint8_t classes_max = 32;
 840                 uint8_t classes_cnt = 0;
 841                 uint16_t classes[classes_max];
 842
 843                 // Parse request hint for IA-PD
 844                 if (is_pd) {
 845                         uint8_t *sdata;
 846                         uint16_t stype, slen;
 847                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 848                                 if (stype != DHCPV6_OPT_IA_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 849                                         continue;
 850
 851                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 852                                 if (p->prefix) {
 853                                         reqlen = p->prefix;
 854                                         reqhint = ntohl(p->addr.s6_addr32[1]);
 855                                         if (reqlen > 32 && reqlen <= 64)
 856                                                 reqhint &= (1U << (64 - reqlen)) - 1;
 857                                 }
 858
 859 #ifdef DHCPV6_OPT_PREFIX_CLASS
 860                                 uint8_t *xdata;
 861                                 uint16_t xtype, xlen;
 862                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 863                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 864                                                 continue;
 865
 866                                         if (classes_cnt >= classes_max)
 867                                                 continue;
 868
 869                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 870                                 }
 871 #endif
 872                         }
 873
 874                         if (reqlen > 64)
 875                                 reqlen = 64;
 876                 } else if (is_na) {
 877                         uint8_t *sdata;
 878                         uint16_t stype, slen;
 879                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 880                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
 881                                         continue;
 882
 883 #ifdef DHCPV6_OPT_PREFIX_CLASS
 884                                 uint8_t *xdata;
 885                                 uint16_t xtype, xlen;
 886                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
 887                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 888                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 889                                                 continue;
 890
 891                                         if (classes_cnt >= classes_max)
 892                                                 continue;
 893
 894                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 895                                 }
 896 #endif
 897                         }
 898                 }
 899
 900                 // Find assignment
 901                 struct dhcpv6_assignment *c, *a = NULL;
 902                 list_for_each_entry(c, &iface->ia_assignments, head) {
 903                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
 904                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
 905                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
 906                                         (c->iaid == ia->iaid || c->valid_until < now) &&
 907                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
 908                                 a = c;
 909
 910                                 // Reset state
 911                                 apply_lease(iface, a, false);
 912                                 memcpy(a->clid_data, clid_data, clid_len);
 913                                 a->clid_len = clid_len;
 914                                 a->iaid = ia->iaid;
 915                                 a->peer = *addr;
 916                                 a->reconf_cnt = 0;
 917                                 a->reconf_sent = 0;
 918                                 a->all_class = class_oro;
 919                                 a->classes_cnt = classes_cnt;
 920                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
 921                                 if (a->classes)
 922                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 923                                 break;
 924                         }
 925                 }
 926
 927                 // Generic message handling
 928                 uint16_t status = DHCPV6_STATUS_OK;
 929                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
 930                         bool assigned = !!a;
 931
 932                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
 933                                 a = calloc(1, sizeof(*a) + clid_len);
 934                                 if (a) {
 935                                         a->clid_len = clid_len;
 936                                         a->iaid = ia->iaid;
 937                                         a->length = reqlen;
 938                                         a->peer = *addr;
 939                                         a->assigned = reqhint;
 940                                         a->all_class = class_oro;
 941                                         a->classes_cnt = classes_cnt;
 942                                         if (classes_cnt) {
 943                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
 944                                                 if (a->classes)
 945                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 946                                         }
 947
 948                                         if (first)
 949                                                 memcpy(a->key, first->key, sizeof(a->key));
 950                                         else
 951                                                 odhcpd_urandom(a->key, sizeof(a->key));
 952                                         memcpy(a->clid_data, clid_data, clid_len);
 953
 954                                         if (is_pd)
 955                                                 while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64);
 956                                         else
 957                                                 assigned = assign_na(iface, a);
 958                                 }
 959                         }
 960
 961                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
 962                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
 963                         } else if (assigned && !first) { //
 964                                 size_t handshake_len = 4;
 965                                 buf[0] = 0;
 966                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
 967                                 buf[2] = 0;
 968                                 buf[3] = 0;
 969
 970                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
 971                                         struct dhcpv6_auth_reconfigure auth = {
 972                                                 htons(DHCPV6_OPT_AUTH),
 973                                                 htons(sizeof(auth) - 4),
 974                                                 3, 1, 0,
 975                                                 {htonl(time(NULL)), htonl(++serial)},
 976                                                 1,
 977                                                 {0}
 978                                         };
 979                                         memcpy(auth.key, a->key, sizeof(a->key));
 980                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
 981                                         handshake_len += sizeof(auth);
 982                                 }
 983
 984                                 buf += handshake_len;
 985                                 buflen -= handshake_len;
 986                                 response_len += handshake_len;
 987
 988                                 first = a;
 989                         }
 990
 991                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
 992
 993                         // Was only a solicitation: mark binding for removal
 994                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
 995                                 a->valid_until = 0;
 996                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
 997                                 if (hostname_len > 0) {
 998                                         a->hostname = realloc(a->hostname, hostname_len + 1);
 999                                         if (a->hostname) {
1000                                                 memcpy(a->hostname, hostname, hostname_len);
1001                                                 a->hostname[hostname_len] = 0;
1002                                         }
1003                                 }
1004                                 a->accept_reconf = accept_reconf;
1005                                 apply_lease(iface, a, true);
1006                                 update_state = true;
1007                         } else if (!assigned && a) { // Cleanup failed assignment
1008                                 free(a->classes);
1009                                 free(a->hostname);
1010                                 free(a);
1011                         }
1012                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1013                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1014                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1015                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1016                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1017                                 status = DHCPV6_STATUS_NOBINDING;
1018                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1019                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1020                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1021                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1022                                 if (a)
1023                                         apply_lease(iface, a, true);
1024                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1025                                 a->valid_until = 0;
1026                                 apply_lease(iface, a, false);
1027                                 update_state = true;
1028                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1029                                 a->clid_len = 0;
1030                                 a->valid_until = now + 3600; // Block address for 1h
1031                                 update_state = true;
1032                         }
1033                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1034                         // Always send NOTONLINK for CONFIRM so that clients restart connection
1035                         status = DHCPV6_STATUS_NOTONLINK;
1036                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1037                 }
1038
1039                 buf += ia_response_len;
1040                 buflen -= ia_response_len;
1041                 response_len += ia_response_len;
1042         }
1043
1044         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1045                 buf[0] = 0;
1046                 buf[1] = DHCPV6_OPT_STATUS;
1047                 buf[2] = 0;
1048                 buf[3] = 2;
1049                 buf[4] = 0;
1050                 buf[5] = DHCPV6_STATUS_OK;
1051                 response_len += 6;
1052         }
1053
1054         if (update_state)
1055                 dhcpv6_write_statefile();
1056
1057 out:
1058         return response_len;
1059 }