src/dhcpv6-ia.c

   1 /**
   2  * Copyright (C) 2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include "odhcpd.h"
  16 #include "dhcpv6.h"
  17 #include "dhcpv4.h"
  18 #include "libubox/md5.h"
  19
  20 #include <time.h>
  21 #include <errno.h>
  22 #include <fcntl.h>
  23 #include <alloca.h>
  24 #include <resolv.h>
  25 #include <limits.h>
  26 #include <stdlib.h>
  27 #include <unistd.h>
  28 #include <arpa/inet.h>
  29 #include <sys/timerfd.h>
  30
  31
  32 static void update(struct interface *iface);
  33 static void reconf_timer(struct uloop_timeout *event);
  34 static struct uloop_timeout reconf_event = {.cb = reconf_timer};
  35 static uint32_t serial = 0;
  36 static uint8_t statemd5[16];
  37
  38
  39 int dhcpv6_ia_init(void)
  40 {
  41         uloop_timeout_set(&reconf_event, 2000);
  42         return 0;
  43 }
  44
  45
  46 int setup_dhcpv6_ia_interface(struct interface *iface, bool enable)
  47 {
  48         if (!enable && iface->ia_assignments.next) {
  49                 struct dhcpv6_assignment *c;
  50                 while (!list_empty(&iface->ia_assignments)) {
  51                         c = list_first_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
  52                         list_del(&c->head);
  53                         free(c->hostname);
  54                         free(c->classes);
  55                         free(c);
  56                 }
  57         }
  58
  59         if (iface->dhcpv6 == RELAYD_SERVER) {
  60                 if (!iface->ia_assignments.next)
  61                         INIT_LIST_HEAD(&iface->ia_assignments);
  62
  63                 if (list_empty(&iface->ia_assignments)) {
  64                         struct dhcpv6_assignment *border = calloc(1, sizeof(*border));
  65                         if (!border) {
  66                                 syslog(LOG_ERR, "Calloc failed for border on interface %s", iface->ifname);
  67                                 return -1;
  68                         }
  69
  70                         border->length = 64;
  71                         list_add(&border->head, &iface->ia_assignments);
  72                 }
  73
  74                 update(iface);
  75
  76                 // Parse static entries
  77                 struct lease *lease;
  78                 list_for_each_entry(lease, &leases, head) {
  79                         // Construct entry
  80                         struct dhcpv6_assignment *a = calloc(1, sizeof(*a) + lease->duid_len);
  81                         if (!a) {
  82                                 syslog(LOG_ERR, "Calloc failed for static lease assignment on interface %s",
  83                                         iface->ifname);
  84                                 return -1;
  85                         }
  86
  87                         a->clid_len = lease->duid_len;
  88                         a->length = 128;
  89                         if (lease->hostid) {
  90                                 a->assigned = lease->hostid;
  91                         } else {
  92                                 uint32_t i4a = ntohl(lease->ipaddr.s_addr) & 0xff;
  93                                 a->assigned = ((i4a / 100) << 8) | (((i4a % 100) / 10) << 4) | (i4a % 10);
  94                         }
  95                         odhcpd_urandom(a->key, sizeof(a->key));
  96                         memcpy(a->clid_data, lease->duid, a->clid_len);
  97                         memcpy(a->mac, lease->mac.ether_addr_octet, sizeof(a->mac));
  98
  99                         // Assign to all interfaces
 100                         struct dhcpv6_assignment *c;
 101                         list_for_each_entry(c, &iface->ia_assignments, head) {
 102                                 if (c->length != 128 || c->assigned > a->assigned) {
 103                                         list_add_tail(&a->head, &c->head);
 104                                         break;
 105                                 } else if (c->assigned == a->assigned) {
 106                                         // Already an assignment with that number
 107                                         break;
 108                                 }
 109                         }
 110
 111                         if (a->head.next) {
 112                                 if (lease->hostname[0]) {
 113                                         free(a->hostname);
 114                                         a->hostname = strdup(lease->hostname);
 115                                 }
 116                         } else {
 117                                 free(a->classes);
 118                                 free(a->hostname);
 119                                 free(a);
 120                         }
 121                 }
 122         }
 123         return 0;
 124 }
 125
 126
 127 static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign)
 128 {
 129         struct {
 130                 struct dhcpv6_client_header hdr;
 131                 uint16_t srvid_type;
 132                 uint16_t srvid_len;
 133                 uint16_t duid_type;
 134                 uint16_t hardware_type;
 135                 uint8_t mac[6];
 136                 uint16_t msg_type;
 137                 uint16_t msg_len;
 138                 uint8_t msg_id;
 139                 struct dhcpv6_auth_reconfigure auth;
 140                 uint16_t clid_type;
 141                 uint16_t clid_len;
 142                 uint8_t clid_data[128];
 143         } __attribute__((packed)) reconf_msg = {
 144                 .hdr = {DHCPV6_MSG_RECONFIGURE, {0, 0, 0}},
 145                 .srvid_type = htons(DHCPV6_OPT_SERVERID),
 146                 .srvid_len = htons(10),
 147                 .duid_type = htons(3),
 148                 .hardware_type = htons(1),
 149                 .msg_type = htons(DHCPV6_OPT_RECONF_MSG),
 150                 .msg_len = htons(1),
 151                 .msg_id = DHCPV6_MSG_RENEW,
 152                 .auth = {htons(DHCPV6_OPT_AUTH),
 153                                 htons(sizeof(reconf_msg.auth) - 4), 3, 1, 0,
 154                                 {htonl(time(NULL)), htonl(++serial)}, 2, {0}},
 155                 .clid_type = htons(DHCPV6_OPT_CLIENTID),
 156                 .clid_len = htons(assign->clid_len),
 157                 .clid_data = {0},
 158         };
 159
 160         odhcpd_get_mac(iface, reconf_msg.mac);
 161         memcpy(reconf_msg.clid_data, assign->clid_data, assign->clid_len);
 162         struct iovec iov = {&reconf_msg, sizeof(reconf_msg) - 128 + assign->clid_len};
 163
 164         md5_ctx_t md5;
 165         uint8_t secretbytes[16];
 166         memcpy(secretbytes, assign->key, sizeof(secretbytes));
 167
 168         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 169                 secretbytes[i] ^= 0x36;
 170
 171         md5_begin(&md5);
 172         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 173         md5_hash(iov.iov_base, iov.iov_len, &md5);
 174         md5_end(reconf_msg.auth.key, &md5);
 175
 176         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 177                 secretbytes[i] ^= 0x36;
 178                 secretbytes[i] ^= 0x5c;
 179         }
 180
 181         md5_begin(&md5);
 182         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 183         md5_hash(reconf_msg.auth.key, 16, &md5);
 184         md5_end(reconf_msg.auth.key, &md5);
 185
 186         return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 187 }
 188
 189
 190 void dhcpv6_write_statefile(void)
 191 {
 192         md5_ctx_t md5;
 193         md5_begin(&md5);
 194
 195         if (config.dhcp_statefile) {
 196                 time_t now = odhcpd_time(), wall_time = time(NULL);
 197                 int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
 198                 if (fd < 0)
 199                         return;
 200
 201                 lockf(fd, F_LOCK, 0);
 202                 ftruncate(fd, 0);
 203
 204                 FILE *fp = fdopen(fd, "w");
 205                 if (!fp) {
 206                         close(fd);
 207                         return;
 208                 }
 209
 210                 struct interface *iface;
 211                 list_for_each_entry(iface, &interfaces, head) {
 212                         if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
 213                                 continue;
 214
 215                         if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
 216                                 struct dhcpv6_assignment *c;
 217                                 list_for_each_entry(c, &iface->ia_assignments, head) {
 218                                         if (c->clid_len == 0)
 219                                                 continue;
 220
 221                                         char ipbuf[INET6_ADDRSTRLEN];
 222                                         char leasebuf[512];
 223                                         char duidbuf[264];
 224                                         odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
 225
 226                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 227                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %u %x %u ",
 228                                                         iface->ifname, duidbuf, ntohl(c->iaid),
 229                                                         (c->hostname ? c->hostname : "-"),
 230                                                         (unsigned)(c->valid_until > now ?
 231                                                                         (c->valid_until - now + wall_time) : 0),
 232                                                         c->assigned, (unsigned)c->length);
 233
 234                                         struct in6_addr addr;
 235                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 236                                                 if (iface->ia_addr[i].prefix > 96)
 237                                                         continue;
 238
 239                                                 addr = iface->ia_addr[i].addr;
 240                                                 if (c->length == 128)
 241                                                         addr.s6_addr32[3] = htonl(c->assigned);
 242                                                 else
 243                                                         addr.s6_addr32[1] |= htonl(c->assigned);
 244                                                 inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
 245
 246                                                 if (c->length == 128 && c->hostname && i == 0) {
 247                                                         fputs(ipbuf, fp);
 248
 249                                                         char b[256];
 250                                                         if (dn_expand(iface->search, iface->search + iface->search_len,
 251                                                                         iface->search, b, sizeof(b)) > 0)
 252                                                                 fprintf(fp, "\t%s.%s", c->hostname, b);
 253
 254                                                         fprintf(fp, "\t%s\n", c->hostname);
 255                                                         md5_hash(ipbuf, strlen(ipbuf), &md5);
 256                                                         md5_hash(c->hostname, strlen(c->hostname), &md5);
 257                                                 }
 258
 259                                                 l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%hhu ", ipbuf, c->length);
 260                                         }
 261                                         leasebuf[l - 1] = '\n';
 262                                         fwrite(leasebuf, 1, l, fp);
 263                                 }
 264                         }
 265
 266                         if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
 267                                 struct dhcpv4_assignment *c;
 268                                 list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
 269                                         char ipbuf[INET6_ADDRSTRLEN];
 270                                         char leasebuf[512];
 271                                         char duidbuf[16];
 272                                         odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 273
 274                                         // iface DUID iaid hostname lifetime assigned length [addrs...]
 275                                         int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %u %x 32 ",
 276                                                         iface->ifname, duidbuf,
 277                                                         (c->hostname ? c->hostname : "-"),
 278                                                         (unsigned)(c->valid_until > now ?
 279                                                                         (c->valid_until - now + wall_time) : 0),
 280                                                         c->addr);
 281
 282                                         struct in_addr addr = {htonl(c->addr)};
 283                                         inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 284
 285                                         if (c->hostname[0]) {
 286                                                 fputs(ipbuf, fp);
 287
 288                                                 char b[256];
 289                                                 if (dn_expand(iface->search, iface->search + iface->search_len,
 290                                                                 iface->search, b, sizeof(b)) > 0)
 291                                                         fprintf(fp, "\t%s.%s", c->hostname, b);
 292
 293                                                 fprintf(fp, "\t%s\n", c->hostname);
 294                                                 md5_hash(ipbuf, strlen(ipbuf), &md5);
 295                                                 md5_hash(c->hostname, strlen(c->hostname), &md5);
 296                                         }
 297
 298                                         l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
 299                                         leasebuf[l - 1] = '\n';
 300                                         fwrite(leasebuf, 1, l, fp);
 301                                 }
 302                         }
 303                 }
 304
 305                 fclose(fp);
 306         }
 307
 308         uint8_t newmd5[16];
 309         md5_end(newmd5, &md5);
 310
 311         if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
 312                 memcpy(statemd5, newmd5, sizeof(statemd5));
 313                 char *argv[2] = {config.dhcp_cb, NULL};
 314                 if (!vfork()) {
 315                         execv(argv[0], argv);
 316                         _exit(128);
 317                 }
 318         }
 319 }
 320
 321
 322 static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bool add)
 323 {
 324         if (a->length > 64)
 325                 return;
 326
 327         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 328                 struct in6_addr prefix = iface->ia_addr[i].addr;
 329                 prefix.s6_addr32[1] |= htonl(a->assigned);
 330                 odhcpd_setup_route(&prefix, a->length, iface, &a->peer.sin6_addr, add);
 331         }
 332 }
 333
 334
 335 static bool assign_pd(struct interface *iface, struct dhcpv6_assignment *assign)
 336 {
 337         struct dhcpv6_assignment *c;
 338         if (iface->ia_addr_len < 1)
 339                 return false;
 340
 341         // Try honoring the hint first
 342         uint32_t current = 1, asize = (1 << (64 - assign->length)) - 1;
 343         if (assign->assigned) {
 344                 list_for_each_entry(c, &iface->ia_assignments, head) {
 345                         if (c->length == 128)
 346                                 continue;
 347
 348                         if (assign->assigned >= current && assign->assigned + asize < c->assigned) {
 349                                 list_add_tail(&assign->head, &c->head);
 350                                 apply_lease(iface, assign, true);
 351                                 return true;
 352                         }
 353
 354                         if (c->assigned != 0)
 355                                 current = (c->assigned + (1 << (64 - c->length)));
 356                 }
 357         }
 358
 359         // Fallback to a variable assignment
 360         current = 1;
 361         list_for_each_entry(c, &iface->ia_assignments, head) {
 362                 if (c->length == 128)
 363                         continue;
 364
 365                 current = (current + asize) & (~asize);
 366                 if (current + asize < c->assigned) {
 367                         assign->assigned = current;
 368                         list_add_tail(&assign->head, &c->head);
 369                         apply_lease(iface, assign, true);
 370                         return true;
 371                 }
 372
 373                 if (c->assigned != 0)
 374                         current = (c->assigned + (1 << (64 - c->length)));
 375         }
 376
 377         return false;
 378 }
 379
 380
 381 static bool assign_na(struct interface *iface, struct dhcpv6_assignment *assign)
 382 {
 383         bool match = false;
 384         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 385                 if (!iface->ia_addr[i].has_class) {
 386                         match = true;
 387                         continue;
 388                 } else if (assign->classes_cnt) {
 389                         for (size_t j = 0; j < assign->classes_cnt; ++j)
 390                                 if (assign->classes[j] == iface->ia_addr[i].class)
 391                                         match = true;
 392                 } else if (assign->all_class) {
 393                         match = true;
 394                 }
 395         }
 396
 397         if (!match)
 398                 return false;
 399
 400         // Seed RNG with checksum of DUID
 401         uint32_t seed = 0;
 402         for (size_t i = 0; i < assign->clid_len; ++i)
 403                 seed += assign->clid_data[i];
 404         srand(seed);
 405
 406         // Try to assign up to 100x
 407         for (size_t i = 0; i < 100; ++i) {
 408                 uint32_t try;
 409                 do try = ((uint32_t)rand()) % 0x0fff; while (try < 0x100);
 410
 411                 struct dhcpv6_assignment *c;
 412                 list_for_each_entry(c, &iface->ia_assignments, head) {
 413                         if (c->assigned > try || c->length != 128) {
 414                                 assign->assigned = try;
 415                                 list_add_tail(&assign->head, &c->head);
 416                                 return true;
 417                         } else if (c->assigned == try) {
 418                                 break;
 419                         }
 420                 }
 421         }
 422
 423         return false;
 424 }
 425
 426
 427 static int prefixcmp(const void *va, const void *vb)
 428 {
 429         const struct odhcpd_ipaddr *a = va, *b = vb;
 430         uint32_t a_pref = ((a->addr.s6_addr[0] & 0xfe) != 0xfc) ? a->preferred : 1;
 431         uint32_t b_pref = ((b->addr.s6_addr[0] & 0xfe) != 0xfc) ? b->preferred : 1;
 432         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 433 }
 434
 435
 436 static void update(struct interface *iface)
 437 {
 438         struct odhcpd_ipaddr addr[8];
 439         memset(addr, 0, sizeof(addr));
 440         int len = odhcpd_get_interface_addresses(iface->ifindex, addr, 8);
 441
 442         if (len < 0)
 443                 return;
 444
 445         qsort(addr, len, sizeof(*addr), prefixcmp);
 446
 447         time_t now = odhcpd_time();
 448         int minprefix = -1;
 449
 450         for (int i = 0; i < len; ++i) {
 451                 if (addr[i].prefix > minprefix)
 452                         minprefix = addr[i].prefix;
 453
 454                 addr[i].addr.s6_addr32[3] = 0;
 455
 456                 if (addr[i].preferred < UINT32_MAX - now)
 457                         addr[i].preferred += now;
 458
 459                 if (addr[i].valid < UINT32_MAX - now)
 460                         addr[i].valid += now;
 461         }
 462
 463         struct dhcpv6_assignment *border = list_last_entry(&iface->ia_assignments, struct dhcpv6_assignment, head);
 464         border->assigned = 1 << (64 - minprefix);
 465
 466         bool change = len != (int)iface->ia_addr_len;
 467         for (int i = 0; !change && i < len; ++i)
 468                 if (addr[i].addr.s6_addr32[0] != iface->ia_addr[i].addr.s6_addr32[0] ||
 469                                 addr[i].addr.s6_addr32[1] != iface->ia_addr[i].addr.s6_addr32[1] ||
 470                                 (addr[i].preferred > 0) != (iface->ia_addr[i].preferred > 0) ||
 471                                 (addr[i].valid > (uint32_t)now + 7200) !=
 472                                                 (iface->ia_addr[i].valid > (uint32_t)now + 7200))
 473                         change = true;
 474
 475         if (change) {
 476                 struct dhcpv6_assignment *c;
 477                 list_for_each_entry(c, &iface->ia_assignments, head)
 478                         if (c != border)
 479                                 apply_lease(iface, c, false);
 480         }
 481
 482         memcpy(iface->ia_addr, addr, len * sizeof(*addr));
 483         iface->ia_addr_len = len;
 484
 485         if (change) { // Addresses / prefixes have changed
 486                 struct list_head reassign = LIST_HEAD_INIT(reassign);
 487                 struct dhcpv6_assignment *c, *d;
 488                 list_for_each_entry_safe(c, d, &iface->ia_assignments, head) {
 489                         if (c->clid_len == 0 || c->valid_until < now)
 490                                 continue;
 491
 492                         if (c->length < 128 && c->assigned >= border->assigned && c != border)
 493                                 list_move(&c->head, &reassign);
 494                         else if (c != border)
 495                                 apply_lease(iface, c, true);
 496
 497                         if (c->accept_reconf && c->reconf_cnt == 0) {
 498                                 c->reconf_cnt = 1;
 499                                 c->reconf_sent = now;
 500                                 send_reconf(iface, c);
 501
 502                                 // Leave all other assignments of that client alone
 503                                 struct dhcpv6_assignment *a;
 504                                 list_for_each_entry(a, &iface->ia_assignments, head)
 505                                         if (a != c && a->clid_len == c->clid_len &&
 506                                                         !memcmp(a->clid_data, c->clid_data, a->clid_len))
 507                                                 c->reconf_cnt = INT_MAX;
 508                         }
 509                 }
 510
 511                 while (!list_empty(&reassign)) {
 512                         c = list_first_entry(&reassign, struct dhcpv6_assignment, head);
 513                         list_del(&c->head);
 514                         if (!assign_pd(iface, c)) {
 515                                 c->assigned = 0;
 516                                 list_add(&c->head, &iface->ia_assignments);
 517                         }
 518                 }
 519
 520                 dhcpv6_write_statefile();
 521         }
 522 }
 523
 524
 525 static void reconf_timer(struct uloop_timeout *event)
 526 {
 527         time_t now = odhcpd_time();
 528         struct interface *iface;
 529         list_for_each_entry(iface, &interfaces, head) {
 530                 if (iface->dhcpv6 != RELAYD_SERVER || iface->ia_assignments.next == NULL)
 531                         continue;
 532
 533                 struct dhcpv6_assignment *a, *n;
 534                 list_for_each_entry_safe(a, n, &iface->ia_assignments, head) {
 535                         if (a->valid_until < now) {
 536                                 if ((a->length < 128 && a->clid_len > 0) ||
 537                                                 (a->length == 128 && a->clid_len == 0)) {
 538                                         list_del(&a->head);
 539                                         free(a->classes);
 540                                         free(a->hostname);
 541                                         free(a);
 542                                 }
 543                         } else if (a->reconf_cnt > 0 && a->reconf_cnt < 8 &&
 544                                         now > a->reconf_sent + (1 << a->reconf_cnt)) {
 545                                 ++a->reconf_cnt;
 546                                 a->reconf_sent = now;
 547                                 send_reconf(iface, a);
 548                         }
 549                 }
 550
 551                 if (iface->ia_reconf) {
 552                         update(iface);
 553                         iface->ia_reconf = false;
 554                 }
 555         }
 556
 557         uloop_timeout_set(event, 2000);
 558 }
 559
 560
 561 static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 562                 const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
 563                 struct interface *iface, bool request)
 564 {
 565         if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
 566                 return 0;
 567
 568         struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
 569         size_t datalen = sizeof(out);
 570         time_t now = odhcpd_time();
 571
 572         if (status) {
 573                 struct __attribute__((packed)) {
 574                         uint16_t type;
 575                         uint16_t len;
 576                         uint16_t value;
 577                 } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
 578                                 htons(status)};
 579
 580                 memcpy(buf + datalen, &stat, sizeof(stat));
 581                 datalen += sizeof(stat);
 582         } else {
 583                 if (a) {
 584                         uint32_t pref = 3600;
 585                         uint32_t valid = 3600;
 586
 587                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 588                                 bool match = true;
 589                                 if (iface->ia_addr[i].has_class) {
 590                                         match = false;
 591                                         if (a->classes_cnt) {
 592                                                 for (size_t j = 0; j < a->classes_cnt; ++j)
 593                                                         if (a->classes[j] == iface->ia_addr[i].class)
 594                                                                 match = true;
 595                                         } else if (a->all_class) {
 596                                                 match = true;
 597                                         }
 598                                 }
 599
 600                                 if (!match)
 601                                         continue;
 602
 603                                 uint32_t prefix_pref = iface->ia_addr[i].preferred - now;
 604                                 uint32_t prefix_valid = iface->ia_addr[i].valid - now;
 605
 606                                 if (iface->ia_addr[i].prefix > 96 ||
 607                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 608                                         continue;
 609
 610                                 if (prefix_pref > 86400)
 611                                         prefix_pref = 86400;
 612
 613                                 if (prefix_valid > 86400)
 614                                         prefix_valid = 86400;
 615
 616 #ifdef DHCPV6_OPT_PREFIX_CLASS
 617                                 struct {
 618                                         uint16_t code;
 619                                         uint16_t length;
 620                                         uint16_t class;
 621                                 } pclass = {htons(DHCPV6_OPT_PREFIX_CLASS),
 622                                         htons(2), htons(iface->ia_addr[i].class)};
 623 #endif
 624
 625                                 if (a->length < 128) {
 626                                         struct dhcpv6_ia_prefix p = {
 627                                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 628                                                 .len = htons(sizeof(p) - 4),
 629                                                 .preferred = htonl(prefix_pref),
 630                                                 .valid = htonl(prefix_valid),
 631                                                 .prefix = a->length,
 632                                                 .addr = iface->ia_addr[i].addr
 633                                         };
 634                                         p.addr.s6_addr32[1] |= htonl(a->assigned);
 635                                         size_t entrlen = sizeof(p) - 4;
 636
 637 #ifdef DHCPV6_OPT_PREFIX_CLASS
 638                                         if (iface->ia_addr[i].has_class) {
 639                                                 entrlen += sizeof(pclass);
 640                                                 p.len = htons(entrlen);
 641                                         }
 642 #endif
 643
 644                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 645                                                 continue;
 646
 647                                         memcpy(buf + datalen, &p, sizeof(p));
 648 #ifdef DHCPV6_OPT_PREFIX_CLASS
 649                                         memcpy(buf + datalen + sizeof(p), &pclass, sizeof(pclass));
 650 #endif
 651                                         datalen += entrlen + 4;
 652                                 } else {
 653                                         struct dhcpv6_ia_addr n = {
 654                                                 .type = htons(DHCPV6_OPT_IA_ADDR),
 655                                                 .len = htons(sizeof(n) - 4),
 656                                                 .addr = iface->ia_addr[i].addr,
 657                                                 .preferred = htonl(prefix_pref),
 658                                                 .valid = htonl(prefix_valid)
 659                                         };
 660                                         n.addr.s6_addr32[3] = htonl(a->assigned);
 661                                         size_t entrlen = sizeof(n) - 4;
 662
 663 #ifdef DHCPV6_OPT_PREFIX_CLASS
 664                                         if (iface->ia_addr[i].has_class) {
 665                                                 entrlen += sizeof(pclass);
 666                                                 n.len = htons(entrlen);
 667                                         }
 668 #endif
 669
 670                                         if (datalen + entrlen + 4 > buflen || a->assigned == 0)
 671                                                 continue;
 672
 673                                         memcpy(buf + datalen, &n, sizeof(n));
 674 #ifdef DHCPV6_OPT_PREFIX_CLASS
 675                                         memcpy(buf + datalen + sizeof(n), &pclass, sizeof(pclass));
 676 #endif
 677                                         datalen += entrlen + 4;
 678                                 }
 679
 680                                 // Calculate T1 / T2 based on non-deprecated addresses
 681                                 if (prefix_pref > 0) {
 682                                         if (prefix_pref < pref)
 683                                                 pref = prefix_pref;
 684
 685                                         if (prefix_valid < valid)
 686                                                 valid = prefix_valid;
 687                                 }
 688                         }
 689
 690                         a->valid_until = valid + now;
 691                         out.t1 = htonl(pref * 5 / 10);
 692                         out.t2 = htonl(pref * 8 / 10);
 693
 694                         if (!out.t1)
 695                                 out.t1 = htonl(1);
 696
 697                         if (!out.t2)
 698                                 out.t2 = htonl(1);
 699                 }
 700
 701                 if (!request) {
 702                         uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
 703                         uint16_t otype, olen;
 704                         dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
 705                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
 706                                 struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
 707                                 if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
 708                                                 (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
 709                                         continue;
 710
 711                                 bool found = false;
 712                                 if (a) {
 713                                         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 714                                                 if (iface->ia_addr[i].prefix > 96 ||
 715                                                                 iface->ia_addr[i].preferred <= (uint32_t)now)
 716                                                         continue;
 717
 718                                                 struct in6_addr addr = iface->ia_addr[i].addr;
 719                                                 if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
 720                                                         addr.s6_addr32[1] |= htonl(a->assigned);
 721
 722                                                         if (IN6_ARE_ADDR_EQUAL(&p->addr, &addr) &&
 723                                                                         p->prefix == a->length)
 724                                                                 found = true;
 725                                                 } else {
 726                                                         addr.s6_addr32[3] = htonl(a->assigned);
 727
 728                                                         if (IN6_ARE_ADDR_EQUAL(&n->addr, &addr))
 729                                                                 found = true;
 730                                                 }
 731                                         }
 732                                 }
 733
 734                                 if (!found) {
 735                                         if (otype == DHCPV6_OPT_IA_PREFIX) {
 736                                                 struct dhcpv6_ia_prefix inv = {
 737                                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 738                                                         .len = htons(sizeof(inv) - 4),
 739                                                         .preferred = 0,
 740                                                         .valid = 0,
 741                                                         .prefix = p->prefix,
 742                                                         .addr = p->addr
 743                                                 };
 744
 745                                                 if (datalen + sizeof(inv) > buflen)
 746                                                         continue;
 747
 748                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 749                                                 datalen += sizeof(inv);
 750                                         } else {
 751                                                 struct dhcpv6_ia_addr inv = {
 752                                                         .type = htons(DHCPV6_OPT_IA_ADDR),
 753                                                         .len = htons(sizeof(inv) - 4),
 754                                                         .addr = n->addr,
 755                                                         .preferred = 0,
 756                                                         .valid = 0
 757                                                 };
 758
 759                                                 if (datalen + sizeof(inv) > buflen)
 760                                                         continue;
 761
 762                                                 memcpy(buf + datalen, &inv, sizeof(inv));
 763                                                 datalen += sizeof(inv);
 764                                         }
 765                                 }
 766                         }
 767                 }
 768         }
 769
 770         out.len = htons(datalen - 4);
 771         memcpy(buf, &out, sizeof(out));
 772         return datalen;
 773 }
 774
 775
 776 size_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 777                 const struct sockaddr_in6 *addr, const void *data, const uint8_t *end)
 778 {
 779         time_t now = odhcpd_time();
 780         size_t response_len = 0;
 781         const struct dhcpv6_client_header *hdr = data;
 782         uint8_t *start = (uint8_t*)&hdr[1], *odata;
 783         uint16_t otype, olen;
 784
 785         // Find and parse client-id and hostname
 786         bool accept_reconf = false;
 787         uint8_t *clid_data = NULL, clid_len = 0, mac[6] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 788         char hostname[256];
 789         size_t hostname_len = 0;
 790         bool class_oro = false;
 791         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 792                 if (otype == DHCPV6_OPT_CLIENTID) {
 793                         clid_data = odata;
 794                         clid_len = olen;
 795
 796                         if (olen == 14 && odata[0] == 0 && odata[1] == 1)
 797                                 memcpy(mac, &odata[8], sizeof(mac));
 798                         else if (olen == 10 && odata[0] == 0 && odata[1] == 3)
 799                                 memcpy(mac, &odata[4], sizeof(mac));
 800                 } else if (otype == DHCPV6_OPT_FQDN && olen >= 2 && olen <= 255) {
 801                         uint8_t fqdn_buf[256];
 802                         memcpy(fqdn_buf, odata, olen);
 803                         fqdn_buf[olen++] = 0;
 804
 805                         if (dn_expand(&fqdn_buf[1], &fqdn_buf[olen], &fqdn_buf[1], hostname, sizeof(hostname)) > 0)
 806                                 hostname_len = strcspn(hostname, ".");
 807                 } else if (otype == DHCPV6_OPT_ORO) {
 808 #ifdef DHCPV6_OPT_PREFIX_CLASS
 809                         for (size_t i = 0; i + 1 < olen; i += 2) {
 810                                 if (odata[i] == (DHCPV6_OPT_PREFIX_CLASS >> 8) &&
 811                                                 odata[i + 1] == (DHCPV6_OPT_PREFIX_CLASS & 0xff))
 812                                         class_oro = true;
 813                         }
 814 #endif
 815                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 816                         accept_reconf = true;
 817                 }
 818         }
 819
 820         if (!clid_data || !clid_len || clid_len > 130)
 821                 goto out;
 822
 823         update(iface);
 824         bool update_state = false;
 825
 826         struct dhcpv6_assignment *first = NULL;
 827         dhcpv6_for_each_option(start, end, otype, olen, odata) {
 828                 bool is_pd = (otype == DHCPV6_OPT_IA_PD);
 829                 bool is_na = (otype == DHCPV6_OPT_IA_NA);
 830                 if (!is_pd && !is_na)
 831                         continue;
 832
 833                 struct dhcpv6_ia_hdr *ia = (struct dhcpv6_ia_hdr*)&odata[-4];
 834                 size_t ia_response_len = 0;
 835                 uint8_t reqlen = (is_pd) ? 62 : 128;
 836                 uint32_t reqhint = 0;
 837
 838                 const uint8_t classes_max = 32;
 839                 uint8_t classes_cnt = 0;
 840                 uint16_t classes[classes_max];
 841
 842                 // Parse request hint for IA-PD
 843                 if (is_pd) {
 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_PREFIX || slen < sizeof(struct dhcpv6_ia_prefix) - 4)
 848                                         continue;
 849
 850                                 struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&sdata[-4];
 851                                 if (p->prefix) {
 852                                         reqlen = p->prefix;
 853                                         reqhint = ntohl(p->addr.s6_addr32[1]);
 854                                         if (reqlen > 32 && reqlen <= 64)
 855                                                 reqhint &= (1U << (64 - reqlen)) - 1;
 856                                 }
 857
 858 #ifdef DHCPV6_OPT_PREFIX_CLASS
 859                                 uint8_t *xdata;
 860                                 uint16_t xtype, xlen;
 861                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 862                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 863                                                 continue;
 864
 865                                         if (classes_cnt >= classes_max)
 866                                                 continue;
 867
 868                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 869                                 }
 870 #endif
 871                         }
 872
 873                         if (reqlen > 64)
 874                                 reqlen = 64;
 875                 } else if (is_na) {
 876                         uint8_t *sdata;
 877                         uint16_t stype, slen;
 878                         dhcpv6_for_each_option(&ia[1], odata + olen, stype, slen, sdata) {
 879                                 if (stype != DHCPV6_OPT_IA_ADDR || slen < sizeof(struct dhcpv6_ia_addr) - 4)
 880                                         continue;
 881
 882 #ifdef DHCPV6_OPT_PREFIX_CLASS
 883                                 uint8_t *xdata;
 884                                 uint16_t xtype, xlen;
 885                                 struct dhcpv6_ia_addr *p = (struct dhcpv6_ia_addr*)&sdata[-4];
 886                                 dhcpv6_for_each_option(&p[1], sdata + slen, xtype, xlen, xdata) {
 887                                         if (xtype != DHCPV6_OPT_PREFIX_CLASS || xlen != 2)
 888                                                 continue;
 889
 890                                         if (classes_cnt >= classes_max)
 891                                                 continue;
 892
 893                                         classes[classes_cnt++] = (uint16_t)xdata[0] << 8 | (uint16_t)xdata[1];
 894                                 }
 895 #endif
 896                         }
 897                 }
 898
 899                 // Find assignment
 900                 struct dhcpv6_assignment *c, *a = NULL;
 901                 list_for_each_entry(c, &iface->ia_assignments, head) {
 902                         if (((c->clid_len == clid_len && !memcmp(c->clid_data, clid_data, clid_len)) ||
 903                                         (c->clid_len >= clid_len && !c->clid_data[0] && !c->clid_data[1]
 904                                                 && !memcmp(c->mac, mac, sizeof(mac)))) &&
 905                                         (c->iaid == ia->iaid || c->valid_until < now) &&
 906                                         ((is_pd && c->length <= 64) || (is_na && c->length == 128))) {
 907                                 a = c;
 908
 909                                 // Reset state
 910                                 apply_lease(iface, a, false);
 911                                 memcpy(a->clid_data, clid_data, clid_len);
 912                                 a->clid_len = clid_len;
 913                                 a->iaid = ia->iaid;
 914                                 a->peer = *addr;
 915                                 a->reconf_cnt = 0;
 916                                 a->reconf_sent = 0;
 917                                 a->all_class = class_oro;
 918                                 a->classes_cnt = classes_cnt;
 919                                 a->classes = realloc(a->classes, classes_cnt * sizeof(uint16_t));
 920                                 if (a->classes)
 921                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 922                                 break;
 923                         }
 924                 }
 925
 926                 // Generic message handling
 927                 uint16_t status = DHCPV6_STATUS_OK;
 928                 if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
 929                         bool assigned = !!a;
 930
 931                         if (!a && !iface->no_dynamic_dhcp) { // Create new binding
 932                                 a = calloc(1, sizeof(*a) + clid_len);
 933                                 if (a) {
 934                                         a->clid_len = clid_len;
 935                                         a->iaid = ia->iaid;
 936                                         a->length = reqlen;
 937                                         a->peer = *addr;
 938                                         a->assigned = reqhint;
 939                                         a->all_class = class_oro;
 940                                         a->classes_cnt = classes_cnt;
 941                                         if (classes_cnt) {
 942                                                 a->classes = malloc(classes_cnt * sizeof(uint16_t));
 943                                                 if (a->classes)
 944                                                         memcpy(a->classes, classes, classes_cnt * sizeof(uint16_t));
 945                                         }
 946
 947                                         if (first)
 948                                                 memcpy(a->key, first->key, sizeof(a->key));
 949                                         else
 950                                                 odhcpd_urandom(a->key, sizeof(a->key));
 951                                         memcpy(a->clid_data, clid_data, clid_len);
 952
 953                                         if (is_pd)
 954                                                 while (!(assigned = assign_pd(iface, a)) && ++a->length <= 64);
 955                                         else
 956                                                 assigned = assign_na(iface, a);
 957                                 }
 958                         }
 959
 960                         if (!assigned || iface->ia_addr_len == 0) { // Set error status
 961                                 status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
 962                         } else if (assigned && !first) { //
 963                                 size_t handshake_len = 4;
 964                                 buf[0] = 0;
 965                                 buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
 966                                 buf[2] = 0;
 967                                 buf[3] = 0;
 968
 969                                 if (hdr->msg_type == DHCPV6_MSG_REQUEST) {
 970                                         struct dhcpv6_auth_reconfigure auth = {
 971                                                 htons(DHCPV6_OPT_AUTH),
 972                                                 htons(sizeof(auth) - 4),
 973                                                 3, 1, 0,
 974                                                 {htonl(time(NULL)), htonl(++serial)},
 975                                                 1,
 976                                                 {0}
 977                                         };
 978                                         memcpy(auth.key, a->key, sizeof(a->key));
 979                                         memcpy(buf + handshake_len, &auth, sizeof(auth));
 980                                         handshake_len += sizeof(auth);
 981                                 }
 982
 983                                 buf += handshake_len;
 984                                 buflen -= handshake_len;
 985                                 response_len += handshake_len;
 986
 987                                 first = a;
 988                         }
 989
 990                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
 991
 992                         // Was only a solicitation: mark binding for removal
 993                         if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
 994                                 a->valid_until = 0;
 995                         } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
 996                                 if (hostname_len > 0) {
 997                                         a->hostname = realloc(a->hostname, hostname_len + 1);
 998                                         if (a->hostname) {
 999                                                 memcpy(a->hostname, hostname, hostname_len);
1000                                                 a->hostname[hostname_len] = 0;
1001                                         }
1002                                 }
1003                                 a->accept_reconf = accept_reconf;
1004                                 apply_lease(iface, a, true);
1005                                 update_state = true;
1006                         } else if (!assigned && a) { // Cleanup failed assignment
1007                                 free(a->classes);
1008                                 free(a->hostname);
1009                                 free(a);
1010                         }
1011                 } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1012                                 hdr->msg_type == DHCPV6_MSG_RELEASE ||
1013                                 hdr->msg_type == DHCPV6_MSG_REBIND ||
1014                                 hdr->msg_type == DHCPV6_MSG_DECLINE) {
1015                         if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
1016                                 status = DHCPV6_STATUS_NOBINDING;
1017                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1018                         } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
1019                                         hdr->msg_type == DHCPV6_MSG_REBIND) {
1020                                 ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
1021                                 if (a)
1022                                         apply_lease(iface, a, true);
1023                         } else if (hdr->msg_type == DHCPV6_MSG_RELEASE) {
1024                                 a->valid_until = 0;
1025                                 apply_lease(iface, a, false);
1026                                 update_state = true;
1027                         } else if (hdr->msg_type == DHCPV6_MSG_DECLINE && a->length == 128) {
1028                                 a->clid_len = 0;
1029                                 a->valid_until = now + 3600; // Block address for 1h
1030                                 update_state = true;
1031                         }
1032                 } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM) {
1033                         // Always send NOTONLINK for CONFIRM so that clients restart connection
1034                         status = DHCPV6_STATUS_NOTONLINK;
1035                         ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
1036                 }
1037
1038                 buf += ia_response_len;
1039                 buflen -= ia_response_len;
1040                 response_len += ia_response_len;
1041         }
1042
1043         if (hdr->msg_type == DHCPV6_MSG_RELEASE && response_len + 6 < buflen) {
1044                 buf[0] = 0;
1045                 buf[1] = DHCPV6_OPT_STATUS;
1046                 buf[2] = 0;
1047                 buf[3] = 2;
1048                 buf[4] = 0;
1049                 buf[5] = DHCPV6_STATUS_OK;
1050                 response_len += 6;
1051         }
1052
1053         if (update_state)
1054                 dhcpv6_write_statefile();
1055
1056 out:
1057         return response_len;
1058 }