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