src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012 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 <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <signal.h>
  19 #include <limits.h>
  20 #include <resolv.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <syslog.h>
  24 #include <stdbool.h>
  25 #include <sys/time.h>
  26 #include <sys/ioctl.h>
  27 #include <sys/socket.h>
  28 #include <netinet/in.h>
  29
  30 #include <net/if.h>
  31 #include <net/ethernet.h>
  32
  33 #include "odhcp6c.h"
  34
  35
  36 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  37                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  38 #define DHCPV6_CLIENT_PORT 546
  39 #define DHCPV6_SERVER_PORT 547
  40 #define DHCPV6_DUID_LLADDR 3
  41 #define DHCPV6_REQ_DELAY 1
  42
  43
  44 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  45                 const uint8_t transaction[3], enum dhcpv6_msg type);
  46
  47 static time_t dhcpv6_parse_ia(void *opt, void *end);
  48
  49 static reply_handler dhcpv6_handle_reply;
  50 static reply_handler dhcpv6_handle_advert;
  51 static reply_handler dhcpv6_handle_rebind_reply;
  52 static reply_handler dhcpv6_handle_reconfigure;
  53 static int dhcpv6_commit_advert(uint32_t elapsed);
  54
  55
  56
  57 // RFC 3315 - 5.5 Timeout and Delay values
  58 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  59         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, "<POLL>",
  60                         dhcpv6_handle_reconfigure, NULL},
  61         [DHCPV6_MSG_SOLICIT] = {true, 1, 120, "SOLICIT",
  62                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  63         [DHCPV6_MSG_REQUEST] = {true, 30, 10, "REQUEST",
  64                         dhcpv6_handle_reply, NULL},
  65         [DHCPV6_MSG_RENEW] = {false, 10, 600, "RENEW",
  66                         dhcpv6_handle_reply, NULL},
  67         [DHCPV6_MSG_REBIND] = {false, 10, 600, "REBIND",
  68                         dhcpv6_handle_rebind_reply, NULL},
  69         [DHCPV6_MSG_RELEASE] = {false, 1, 600, "RELEASE", NULL, NULL},
  70         [DHCPV6_MSG_DECLINE] = {false, 1, 3, "DECLINE", NULL, NULL},
  71         [DHCPV6_MSG_INFO_REQ] = {true, 1, 120, "INFOREQ",
  72                         dhcpv6_handle_reply, NULL},
  73 };
  74
  75
  76 // Sockets
  77 static int sock = -1;
  78 static int urandom_fd = -1;
  79 static int ifindex = -1;
  80 static time_t t1 = 0, t2 = 0, t3 = 0;
  81
  82 // IA states
  83 static int request_prefix = -1;
  84 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE;
  85 static bool accept_reconfig = false;
  86
  87
  88
  89 int init_dhcpv6(const char *ifname, int request_pd)
  90 {
  91         request_prefix = request_pd;
  92         urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY);
  93         if (urandom_fd < 0)
  94                 return -1;
  95
  96         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
  97
  98         // Detect interface
  99         struct ifreq ifr;
 100         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 101         if (ioctl(sock, SIOCGIFINDEX, &ifr))
 102                 return -1;
 103         ifindex = ifr.ifr_ifindex;
 104
 105         // Create client DUID
 106         size_t client_id_len;
 107         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 108         if (client_id_len == 0) {
 109                 ioctl(sock, SIOCGIFHWADDR, &ifr);
 110                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 111                                 DHCPV6_DUID_LLADDR, 0, 1};
 112                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 113
 114                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 115                 struct ifreq ifs[100], *ifp, *ifend;
 116                 struct ifconf ifc;
 117                 ifc.ifc_req = ifs;
 118                 ifc.ifc_len = sizeof(ifs);
 119
 120                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 121                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 122                         // If our interface doesn't have an address...
 123                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 124                         for (ifp = ifc.ifc_req; ifp < ifend &&
 125                                         !memcmp(&duid[8], zero, 6); ifp++) {
 126                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 127                                                 sizeof(ifr.ifr_name));
 128                                 ioctl(sock, SIOCGIFHWADDR, &ifr);
 129                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 130                                                 ETHER_ADDR_LEN);
 131                         }
 132                 }
 133
 134                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 135         }
 136
 137         // Create ORO
 138         uint16_t oro[] = {htons(DHCPV6_OPT_DNS_SERVERS),
 139                         htons(DHCPV6_OPT_DNS_DOMAIN),
 140                         htons(DHCPV6_OPT_NTP_SERVER),
 141                         htons(DHCPV6_OPT_SIP_SERVER_A),
 142                         htons(DHCPV6_OPT_SIP_SERVER_D)};
 143         odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 144
 145
 146         // Configure IPv6-options
 147         int val = 1;
 148         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 149         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 150         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 151
 152         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 153                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 154         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)))
 155                 return -1;
 156
 157         return 0;
 158 }
 159
 160
 161 void dhcpv6_set_ia_na_mode(enum odhcp6c_ia_mode mode)
 162 {
 163         na_mode = mode;
 164 }
 165
 166
 167 void dhcpv6_remove_addrs(void)
 168 {
 169         size_t ia_na_len;
 170         uint8_t *odata, *ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 171         uint16_t otype, olen;
 172         dhcpv6_for_each_option(ia_na, ia_na + ia_na_len, otype, olen, odata) {
 173                 struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
 174                 set_rtnetlink_addr(ifindex, &addr->addr, 0, 0);
 175         }
 176 }
 177
 178
 179 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 180 {
 181         // Build FQDN
 182         char fqdn_buf[256];
 183         gethostname(fqdn_buf, sizeof(fqdn_buf));
 184         struct {
 185                 uint16_t type;
 186                 uint16_t len;
 187                 uint8_t flags;
 188                 uint8_t data[256];
 189         } fqdn;
 190         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 191                         sizeof(fqdn.data), NULL, NULL);
 192         fqdn.type = htons(DHCPV6_OPT_FQDN);
 193         fqdn.len = htons(fqdn_len - 4);
 194         fqdn.flags = 0;
 195
 196
 197         // Build Client ID
 198         size_t cl_id_len;
 199         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 200
 201         // Get Server ID
 202         size_t srv_id_len;
 203         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 204
 205         // Build IA_PDs
 206         size_t ia_pd_len;
 207         void *ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 208         struct dhcpv6_ia_hdr hdr_ia_pd = {
 209                 htons(DHCPV6_OPT_IA_PD),
 210                 htons(sizeof(hdr_ia_pd) - 4 + ia_pd_len),
 211                 1, 0, 0
 212         };
 213
 214         struct dhcpv6_ia_prefix pref = {
 215                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 216                 .len = htons(25), .prefix = request_prefix
 217         };
 218
 219         if (ia_pd_len == 0 && request_prefix > 0 &&
 220                         (type == DHCPV6_MSG_SOLICIT ||
 221                         type == DHCPV6_MSG_REQUEST)) {
 222                 ia_pd = &pref;
 223                 ia_pd_len = sizeof(pref);
 224         }
 225
 226         // Build IA_NAs
 227         size_t ia_na_len;
 228         void *ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 229         struct dhcpv6_ia_hdr hdr_ia_na = {
 230                 htons(DHCPV6_OPT_IA_NA),
 231                 htons(sizeof(hdr_ia_na) - 4 + ia_na_len),
 232                 1, 0, 0
 233         };
 234
 235         // Reconfigure Accept
 236         struct {
 237                 uint16_t type;
 238                 uint16_t length;
 239         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 240
 241         // Request Information Refresh
 242         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 243
 244         // Prepare Header
 245         size_t oro_len;
 246         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 247         struct {
 248                 uint8_t type;
 249                 uint8_t trid[3];
 250                 uint16_t elapsed_type;
 251                 uint16_t elapsed_len;
 252                 uint16_t elapsed_value;
 253                 uint16_t oro_type;
 254                 uint16_t oro_len;
 255         } hdr = {
 256                 type, {trid[0], trid[1], trid[2]},
 257                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 258                         htons((ecs > 0xffff) ? 0xffff : ecs),
 259                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 260         };
 261
 262         struct iovec iov[] = {
 263                 {&hdr, sizeof(hdr)},
 264                 {oro, oro_len},
 265                 {&oro_refresh, 0},
 266                 {cl_id, cl_id_len},
 267                 {srv_id, srv_id_len},
 268                 {&reconf_accept, 0},
 269                 {&fqdn, fqdn_len},
 270                 {&hdr_ia_na, sizeof(hdr_ia_na)},
 271                 {ia_na, ia_na_len},
 272                 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
 273                 {ia_pd, ia_pd_len},
 274         };
 275
 276         size_t cnt = ARRAY_SIZE(iov);
 277         if (type == DHCPV6_MSG_INFO_REQ) {
 278                 cnt = 5;
 279                 iov[2].iov_len = sizeof(oro_refresh);
 280                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 281         } else if (!request_prefix) {
 282                 cnt = 9;
 283         }
 284
 285         // Disable IAs if not used
 286         if (type == DHCPV6_MSG_SOLICIT) {
 287                 iov[5].iov_len = sizeof(reconf_accept);
 288         } else if (type != DHCPV6_MSG_REQUEST) {
 289                 if (ia_na_len == 0)
 290                         iov[7].iov_len = 0;
 291                 if (ia_pd_len == 0)
 292                         iov[9].iov_len = 0;
 293         }
 294
 295         if (na_mode == IA_MODE_NONE)
 296                 iov[7].iov_len = 0;
 297
 298         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 299                 0, ALL_DHCPV6_RELAYS, ifindex};
 300         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 301
 302         sendmsg(sock, &msg, 0);
 303 }
 304
 305
 306 static int64_t dhcpv6_rand_delay(int64_t time)
 307 {
 308         int random;
 309         read(urandom_fd, &random, sizeof(random));
 310         return (time * (random % 1000)) / 10000;
 311 }
 312
 313
 314 int dhcpv6_request(enum dhcpv6_msg type)
 315 {
 316         uint8_t buf[1536];
 317         uint32_t timeout = UINT32_MAX;
 318         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 319
 320         if (retx->delay) {
 321                 struct timespec ts = {0, 0};
 322                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 323                 nanosleep(&ts, NULL);
 324         }
 325
 326         if (type == DHCPV6_MSG_RELEASE || type == DHCPV6_MSG_DECLINE)
 327                 timeout = 3;
 328         else if (type == DHCPV6_MSG_UNKNOWN)
 329                 timeout = t1;
 330         else if (type == DHCPV6_MSG_RENEW)
 331                 timeout = t2 - t1;
 332         else if (type == DHCPV6_MSG_REBIND)
 333                 timeout = t3 - t2;
 334
 335         if (timeout == 0)
 336                 return -1;
 337
 338         syslog(LOG_NOTICE, "Sending %s (timeout %us)", retx->name, timeout);
 339
 340         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 341
 342         // Generate transaction ID
 343         uint8_t trid[3];
 344         read(urandom_fd, trid, sizeof(trid));
 345         ssize_t len = -1;
 346         int64_t rto = 0;
 347
 348         do {
 349                 rto = (rto == 0) ? (retx->init_timeo * 1000 +
 350                                 dhcpv6_rand_delay(retx->init_timeo * 1000)) :
 351                                 (2 * rto + dhcpv6_rand_delay(rto));
 352
 353                 if (rto >= retx->max_timeo * 1000)
 354                         rto = retx->max_timeo * 1000 +
 355                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 356
 357                 // Calculate end for this round and elapsed time
 358                 uint64_t round_end = round_start + rto;
 359                 elapsed = round_start - start;
 360
 361                 // Don't wait too long
 362                 if (round_end - start > timeout * 1000)
 363                         round_end = timeout * 1000 + start;
 364
 365                 // Built and send package
 366                 if (type != DHCPV6_MSG_UNKNOWN)
 367                         dhcpv6_send(type, trid, elapsed / 10);
 368
 369                 // Receive rounds
 370                 for (; len < 0 && round_start < round_end;
 371                                 round_start = odhcp6c_get_milli_time()) {
 372                         // Check for pending signal
 373                         if (odhcp6c_signal_is_pending())
 374                                 return -1;
 375
 376                         // Set timeout for receiving
 377                         uint64_t t = round_end - round_start;
 378                         struct timeval timeout = {t / 1000, (t % 1000) * 1000};
 379                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 380                                         &timeout, sizeof(timeout));
 381
 382                         // Receive cycle
 383                         len = recv(sock, buf, sizeof(buf), 0);
 384
 385                         if (!dhcpv6_response_is_valid(buf, len, trid, type))
 386                                 len = -1;
 387
 388                         if (len > 0) {
 389                                 uint8_t *opt = &buf[4];
 390                                 uint8_t *opt_end = opt + len - 4;
 391
 392                                 round_start = odhcp6c_get_milli_time();
 393                                 elapsed = round_start - start;
 394                                 syslog(LOG_NOTICE, "Got a valid reply after "
 395                                                 "%ums", (unsigned)elapsed);
 396
 397                                 if (retx->handler_reply)
 398                                         len = retx->handler_reply(type,
 399                                                 opt, opt_end, elapsed / 1000);
 400                         }
 401                 }
 402
 403                 // Allow
 404                 if (retx->handler_finish)
 405                         len = retx->handler_finish(elapsed / 1000);
 406         } while (len < 0 && elapsed / 1000 < timeout);
 407
 408         return len;
 409 }
 410
 411
 412 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 413                 const uint8_t transaction[3], enum dhcpv6_msg type)
 414 {
 415         const struct dhcpv6_header *rep = buf;
 416         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 417                         transaction, sizeof(rep->tr_id)))
 418                 return false; // Invalid reply
 419
 420         if (type == DHCPV6_MSG_SOLICIT) {
 421                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 422                                 rep->msg_type != DHCPV6_MSG_REPLY)
 423                         return false;
 424         } else if (type == DHCPV6_MSG_UNKNOWN) {
 425                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 426                         return false;
 427         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 428                 return false;
 429         }
 430
 431         uint8_t *end = ((uint8_t*)buf) + len, *odata;
 432         uint16_t otype, olen;
 433         bool clientid_ok = false, serverid_ok = false;
 434
 435         size_t client_id_len, server_id_len;
 436         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 437         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 438
 439         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata)
 440                 if (otype == DHCPV6_OPT_CLIENTID)
 441                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 442                                         &odata[-4], client_id, client_id_len);
 443                 else if (otype == DHCPV6_OPT_SERVERID)
 444                         serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 445                                         &odata[-4], server_id, server_id_len);
 446
 447         return clientid_ok && (serverid_ok || server_id_len == 0);
 448 }
 449
 450
 451 int dhcpv6_poll_reconfigure(void)
 452 {
 453         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 454         if (ret != -1)
 455                 ret = dhcpv6_request(ret);
 456
 457         return ret;
 458 }
 459
 460
 461 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig,
 462                 const void *opt, const void *end, uint32_t elapsed)
 463 {
 464         // TODO: should verify the reconfigure message
 465         uint16_t otype, olen;
 466         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 467         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 468                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 469                                 odata[0] == DHCPV6_MSG_RENEW ||
 470                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 471                         msg = odata[0];
 472
 473         t1 -= elapsed;
 474         t2 -= elapsed;
 475         t3 -= elapsed;
 476
 477         if (t1 < 0)
 478                 t1 = 0;
 479
 480         if (t2 < 0)
 481                 t2 = 0;
 482
 483         if (t3 < 0)
 484                 t3 = 0;
 485
 486         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, NULL, NULL, elapsed);
 487         return msg;
 488 }
 489
 490
 491 // Collect all advertised servers
 492 static int dhcpv6_handle_advert(_unused enum dhcpv6_msg orig,
 493                 const void *opt, const void *end, _unused uint32_t elapsed)
 494 {
 495         uint16_t olen, otype;
 496         uint8_t *odata;
 497         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}};
 498
 499         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 500                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 501                         memcpy(cand.duid, odata, olen);
 502                         cand.duid_len = olen;
 503                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
 504                                 && odata[1] == DHCPV6_NoAddrsAvail) {
 505                         if (na_mode == IA_MODE_FORCE) {
 506                                 return -1;
 507                         } else {
 508                                 cand.has_noaddravail = true;
 509                                 cand.preference -= 1000;
 510                         }
 511                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2 && !odata[0]
 512                                 && odata[1] == DHCPV6_NoPrefixAvail) {
 513                         cand.preference -= 2000;
 514                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 515                                 cand.preference >= 0) {
 516                         cand.preference = odata[1];
 517                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 518                         cand.wants_reconfigure = true;
 519                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 520                         struct dhcpv6_ia_hdr *h = (void*)odata;
 521                         uint8_t *oend = odata + olen, *d;
 522                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 523                                 if (otype == DHCPV6_OPT_IA_PREFIX)
 524                                         cand.preference += 2000;
 525                                 else if (otype == DHCPV6_OPT_STATUS &&
 526                                                 olen >= 2 && d[0] == 0 &&
 527                                                 d[1] == DHCPV6_NoPrefixAvail)
 528                                         cand.preference -= 2000;
 529                         }
 530                 }
 531         }
 532
 533         if (cand.duid_len > 0)
 534                 odhcp6c_add_state(STATE_SERVER_CAND, &cand, sizeof(cand));
 535
 536         return -1;
 537 }
 538
 539
 540 static int dhcpv6_commit_advert(_unused uint32_t elapsed)
 541 {
 542         size_t cand_len;
 543         struct dhcpv6_server_cand *c = NULL, *cand =
 544                         odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
 545
 546         bool retry = false;
 547         for (size_t i = 0; i < cand_len / sizeof(*c); ++i) {
 548                 if (cand[i].has_noaddravail)
 549                         retry = true; // We want to try again
 550
 551                 if (!c || c->preference < cand[i].preference)
 552                         c = &cand[i];
 553         }
 554
 555         if (retry && na_mode == IA_MODE_TRY) {
 556                 // We give it a second try without the IA_NA
 557                 na_mode = IA_MODE_NONE;
 558                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
 559         }
 560
 561         if (c) {
 562                 uint16_t hdr[2] = {htons(DHCPV6_OPT_SERVERID),
 563                                 htons(c->duid_len)};
 564                 odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
 565                 odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
 566                 accept_reconfig = c->wants_reconfigure;
 567         }
 568
 569         odhcp6c_clear_state(STATE_SERVER_CAND);
 570
 571         if (!c)
 572                 return -1;
 573         else if (request_prefix || na_mode != IA_MODE_NONE)
 574                 return DHCPV6_STATEFUL;
 575         else
 576                 return DHCPV6_STATELESS;
 577 }
 578
 579
 580 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig,
 581                 const void *opt, const void *end, uint32_t elapsed)
 582 {
 583         dhcpv6_handle_advert(orig, opt, end, elapsed);
 584         if (dhcpv6_commit_advert(elapsed) < 0)
 585                 return -1;
 586
 587         return dhcpv6_handle_reply(orig, opt, end, elapsed);
 588 }
 589
 590
 591 static int dhcpv6_handle_reply(_unused enum dhcpv6_msg orig,
 592                 const void *opt, const void *end, uint32_t elapsed)
 593 {
 594         uint16_t otype, olen;
 595         uint8_t *odata;
 596         bool have_update = false;
 597
 598         t1 = t2 = t3 = 86400;
 599
 600         size_t ia_na_len, dns_len, search_len, sntp_ip_len, sntp_dns_len;
 601         size_t sip_ip_len, sip_fqdn_len;
 602         uint8_t *ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 603         uint8_t *ia_end;
 604         odhcp6c_get_state(STATE_DNS, &dns_len);
 605         odhcp6c_get_state(STATE_SEARCH, &search_len);
 606         odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 607         odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 608         odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 609         odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 610
 611         // Decrease valid and preferred lifetime of prefixes
 612         size_t ia_pd_len;
 613         uint8_t *ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 614         dhcpv6_for_each_option(ia_pd, ia_pd + ia_pd_len, otype, olen, odata) {
 615                 struct dhcpv6_ia_prefix *p = (void*)&odata[-4];
 616                 uint32_t valid = ntohl(p->valid);
 617                 p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
 618
 619                 uint32_t pref = ntohl(p->preferred);
 620                 p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
 621         }
 622
 623         // Decrease valid and preferred lifetime of addresses
 624         dhcpv6_for_each_option(ia_na, ia_na + ia_na_len, otype, olen, odata) {
 625                 struct dhcpv6_ia_addr *p = (void*)&odata[-4];
 626                 uint32_t valid = ntohl(p->valid);
 627                 p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
 628
 629                 uint32_t pref = ntohl(p->preferred);
 630                 p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
 631         }
 632
 633         // Parse and find all matching IAs
 634         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 635                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 636                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 637                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 638                         time_t l_t1 = ntohl(ia_hdr->t1);
 639                         time_t l_t2 = ntohl(ia_hdr->t2);
 640
 641                         // Test ID and T1-T2 validity
 642                         if (ia_hdr->iaid != 1 || l_t2 < l_t1)
 643                                 continue;
 644
 645                         uint16_t stype, slen;
 646                         uint8_t *sdata;
 647                         // Test status and bail if error
 648                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 649                                         stype, slen, sdata)
 650                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2 &&
 651                                                 (sdata[0] || sdata[1]))
 652                                         continue;
 653
 654                         // Update times
 655                         if (l_t1 > 0 && t1 > l_t1)
 656                                 t1 = l_t1;
 657
 658                         if (l_t2 > 0 && t2 > l_t2)
 659                                 t2 = l_t2;
 660
 661                         // Always report update in case we have IA_PDs so that
 662                         // the state-script is called with updated times
 663                         if (otype == DHCPV6_OPT_IA_PD && request_prefix)
 664                                 have_update = true;
 665
 666                         time_t n = dhcpv6_parse_ia(&ia_hdr[1], odata + olen);
 667
 668                         if (n < t1)
 669                                 t1 = n;
 670
 671                         if (n < t2)
 672                                 t2 = n;
 673
 674                         if (n < t3)
 675                                 t3 = n;
 676
 677                 } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 678                         if (olen % 16 == 0)
 679                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 680                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 681                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 682                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 683                         uint16_t stype, slen;
 684                         uint8_t *sdata;
 685                         // Test status and bail if error
 686                         dhcpv6_for_each_option(odata, odata + olen,
 687                                         stype, slen, sdata) {
 688                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 689                                                 stype == NTP_SRV_ADDR))
 690                                         odhcp6c_add_state(STATE_SNTP_IP,
 691                                                         sdata, slen);
 692                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 693                                         odhcp6c_add_state(STATE_SNTP_FQDN,
 694                                                         sdata, slen);
 695                         }
 696                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 697                         if (olen == 16)
 698                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 699                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 700                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 701                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 702                         uint32_t refresh = ntohl(*((uint32_t*)odata));
 703                         if (refresh < (uint32_t)t1)
 704                                 t1 = refresh;
 705                 } else if (otype != DHCPV6_OPT_CLIENTID &&
 706                                 otype != DHCPV6_OPT_SERVERID) {
 707                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
 708                                         &odata[-4], olen + 4);
 709                 }
 710         }
 711
 712         if (opt) {
 713                 have_update |= odhcp6c_commit_state(STATE_DNS, dns_len);
 714                 have_update |= odhcp6c_commit_state(STATE_SEARCH, search_len);
 715                 have_update |= odhcp6c_commit_state(STATE_SNTP_IP,
 716                                 sntp_ip_len);
 717                 have_update |= odhcp6c_commit_state(STATE_SNTP_FQDN,
 718                                 sntp_dns_len);
 719                 have_update |= odhcp6c_commit_state(STATE_SIP_IP, sip_ip_len);
 720                 have_update |= odhcp6c_commit_state(STATE_SIP_FQDN, sip_fqdn_len);
 721                 size_t new_ia_pd_len, new_ia_na_len;
 722                 odhcp6c_get_state(STATE_IA_PD, &new_ia_pd_len);
 723                 odhcp6c_get_state(STATE_IA_NA, &new_ia_na_len);
 724                 have_update |= (new_ia_pd_len != ia_pd_len) ||
 725                                 (new_ia_na_len != ia_na_len);
 726         }
 727
 728         // Delete prefixes with 0 valid-time
 729         ia_pd = odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 730         ia_end = ia_pd + ia_pd_len;
 731         dhcpv6_for_each_option(ia_pd, ia_end, otype, olen, odata) {
 732                 struct dhcpv6_ia_prefix *p = (void*)&odata[-4];
 733                 while (!p->valid) {
 734                         ia_end = ia_pd + odhcp6c_remove_state(STATE_IA_PD,
 735                                         (uint8_t*)p - ia_pd, olen + 4);
 736                         have_update = true;
 737                 }
 738         }
 739
 740
 741         // Delete addresses with 0 valid-time
 742         ia_na = odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 743         ia_end = ia_na + ia_na_len;
 744         dhcpv6_for_each_option(ia_na, ia_end, otype, olen, odata) {
 745                 struct dhcpv6_ia_addr *p = (void*)&odata[-4];
 746                 while (!p->valid) {
 747                         ia_end = ia_na + odhcp6c_remove_state(STATE_IA_NA,
 748                                         (uint8_t*)p - ia_na, olen + 4);
 749                         have_update = true;
 750                 }
 751         }
 752
 753         return have_update;
 754 }
 755
 756
 757 static time_t dhcpv6_parse_ia(void *opt, void *end)
 758 {
 759         uint32_t timeout = UINT32_MAX; // Minimum timeout
 760         uint16_t otype, olen, stype, slen;
 761         uint8_t *odata, *sdata;
 762
 763         // Update address IA
 764         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 765                 if (otype == DHCPV6_OPT_IA_PREFIX) {
 766                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
 767                         if (olen + 4U < sizeof(*prefix))
 768                                 continue;
 769
 770                         olen = sizeof(*prefix); // Normalize length
 771                         uint32_t valid = ntohl(prefix->valid);
 772                         uint32_t pref = ntohl(prefix->preferred);
 773
 774                         if (pref > valid)
 775                                 continue;
 776
 777                         // Search matching IA
 778                         struct dhcpv6_ia_prefix *local = NULL;
 779                         size_t pd_len;
 780                         uint8_t *pd = odhcp6c_get_state(STATE_IA_PD, &pd_len);
 781                         dhcpv6_for_each_option(pd, pd + pd_len,
 782                                         stype, slen, sdata)
 783                                 if (!memcmp(sdata + 8, odata + 8,
 784                                                 sizeof(local->addr) + 1))
 785                                         local = (void*)&sdata[-4];
 786
 787                         if (local) { // Already know that IA
 788                                 local->preferred = prefix->preferred;
 789                                 local->valid = prefix->valid;
 790                         } else { // New IA
 791                                 odhcp6c_add_state(STATE_IA_PD, prefix, olen);
 792                         }
 793
 794                         if (timeout > valid)
 795                                 timeout = valid;
 796                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
 797                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
 798                         if (olen + 4U < sizeof(*addr))
 799                                 continue;
 800
 801                         olen = sizeof(*addr); // Normalize length
 802                         uint32_t pref = ntohl(addr->preferred);
 803                         uint32_t valid = ntohl(addr->valid);
 804
 805                         if (pref > valid)
 806                                 continue;
 807
 808                         // Search matching IA
 809                         struct dhcpv6_ia_addr *local = NULL;
 810                         size_t na_len;
 811                         uint8_t *na = odhcp6c_get_state(STATE_IA_NA, &na_len);
 812                         dhcpv6_for_each_option(na, na + na_len,
 813                                         stype, slen, sdata)
 814                                 if (!memcmp(sdata, odata, sizeof(local->addr)))
 815                                         local = (void*)&sdata[-4];
 816
 817
 818                         if (local) { // Already know that IA
 819                                 local->preferred = addr->preferred;
 820                                 local->valid = addr->valid;
 821                         } else { // New IA
 822                                 odhcp6c_add_state(STATE_IA_NA, addr, olen);
 823                         }
 824
 825
 826                         if (timeout > valid)
 827                                 timeout = valid;
 828
 829                         if (set_rtnetlink_addr(ifindex, &addr->addr,
 830                                         pref, valid) == -EADDRNOTAVAIL) {
 831                                 dhcpv6_request(DHCPV6_MSG_DECLINE);
 832                                 raise(SIGUSR2);
 833                         }
 834                 }
 835         }
 836
 837         return timeout;
 838 }