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