src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2013 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 <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <stdlib.h>
  19 #include <signal.h>
  20 #include <limits.h>
  21 #include <resolv.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <syslog.h>
  25 #include <stdbool.h>
  26 #include <sys/time.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/socket.h>
  29 #include <netinet/in.h>
  30
  31 #include <net/if.h>
  32 #include <net/ethernet.h>
  33
  34 #include "odhcp6c.h"
  35 #include "md5.h"
  36
  37
  38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  39                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  40 #define DHCPV6_CLIENT_PORT 546
  41 #define DHCPV6_SERVER_PORT 547
  42 #define DHCPV6_DUID_LLADDR 3
  43 #define DHCPV6_REQ_DELAY 1
  44
  45 #define DHCPV6_SOL_MAX_RT_MIN 60
  46 #define DHCPV6_SOL_MAX_RT_MAX 86400
  47 #define DHCPV6_INF_MAX_RT_MIN 60
  48 #define DHCPV6_INF_MAX_RT_MAX 86400
  49
  50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  51                 const uint8_t transaction[3], enum dhcpv6_msg type,
  52                 const struct in6_addr *daddr);
  53
  54 static int dhcpv6_parse_ia(void *opt, void *end);
  55
  56 static int dhcpv6_calc_refresh_timers(void);
  57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  58                 const uint16_t code, const void *status_msg, const int len,
  59                 int *ret);
  60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  61                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  62                 const void *status_msg, const int len,
  63                 bool handled_status_codes[_DHCPV6_Status_Max],
  64                 int *ret);
  65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  66 static void dhcpv6_clear_all_server_cand(void);
  67
  68 static reply_handler dhcpv6_handle_reply;
  69 static reply_handler dhcpv6_handle_advert;
  70 static reply_handler dhcpv6_handle_rebind_reply;
  71 static reply_handler dhcpv6_handle_reconfigure;
  72 static int dhcpv6_commit_advert(void);
  73
  74
  75
  76 // RFC 3315 - 5.5 Timeout and Delay values
  77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  78         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  79                         dhcpv6_handle_reconfigure, NULL},
  80         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  81                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  82         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  83                         dhcpv6_handle_reply, NULL},
  84         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  85                         dhcpv6_handle_reply, NULL},
  86         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  87                         dhcpv6_handle_rebind_reply, NULL},
  88         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  89         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  90         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  91                         dhcpv6_handle_reply, NULL},
  92 };
  93
  94
  95 // Sockets
  96 static int sock = -1;
  97 static int ifindex = -1;
  98 static int64_t t1 = 0, t2 = 0, t3 = 0;
  99
 100 // IA states
 101 static int request_prefix = -1;
 102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 103 static bool accept_reconfig = false;
 104
 105 // Reconfigure key
 106 static uint8_t reconf_key[16];
 107
 108
 109 int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
 110 {
 111         request_prefix = request_pd;
 112         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 113
 114         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 115         if (sock < 0)
 116                 return -1;
 117
 118         // Detect interface
 119         struct ifreq ifr;
 120         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 121         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 122                 return -1;
 123         ifindex = ifr.ifr_ifindex;
 124
 125         // Create client DUID
 126         size_t client_id_len;
 127         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 128         if (client_id_len == 0) {
 129                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 130                                 DHCPV6_DUID_LLADDR, 0, 1};
 131
 132                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 133                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 134
 135                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 136                 struct ifreq ifs[100], *ifp, *ifend;
 137                 struct ifconf ifc;
 138                 ifc.ifc_req = ifs;
 139                 ifc.ifc_len = sizeof(ifs);
 140
 141                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 142                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 143                         // If our interface doesn't have an address...
 144                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 145                         for (ifp = ifc.ifc_req; ifp < ifend &&
 146                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 147                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 148                                                 sizeof(ifr.ifr_name));
 149                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 150                                         continue;
 151
 152                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 153                                                 ETHER_ADDR_LEN);
 154                         }
 155                 }
 156
 157                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 158         }
 159
 160         // Create ORO
 161         uint16_t oro[] = {
 162                         htons(DHCPV6_OPT_SIP_SERVER_D),
 163                         htons(DHCPV6_OPT_SIP_SERVER_A),
 164                         htons(DHCPV6_OPT_DNS_SERVERS),
 165                         htons(DHCPV6_OPT_DNS_DOMAIN),
 166                         htons(DHCPV6_OPT_NTP_SERVER),
 167                         htons(DHCPV6_OPT_AFTR_NAME),
 168                         htons(DHCPV6_OPT_PD_EXCLUDE),
 169                         htons(DHCPV6_OPT_SOL_MAX_RT),
 170                         htons(DHCPV6_OPT_INF_MAX_RT),
 171 #ifdef EXT_PREFIX_CLASS
 172                         htons(DHCPV6_OPT_PREFIX_CLASS),
 173 #endif
 174         };
 175         odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 176
 177         // Configure IPv6-options
 178         int val = 1;
 179         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 180         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 181         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 182         val = 0;
 183         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
 184         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 185
 186         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 187                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 188         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 189                 return -1;
 190
 191         return 0;
 192 }
 193
 194
 195 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 196 {
 197         na_mode = na;
 198         pd_mode = pd;
 199 }
 200
 201
 202 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 203 {
 204         // Build FQDN
 205         char fqdn_buf[256];
 206         gethostname(fqdn_buf, sizeof(fqdn_buf));
 207         struct {
 208                 uint16_t type;
 209                 uint16_t len;
 210                 uint8_t flags;
 211                 uint8_t data[256];
 212         } fqdn;
 213         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 214                         sizeof(fqdn.data), NULL, NULL);
 215         fqdn.type = htons(DHCPV6_OPT_FQDN);
 216         fqdn.len = htons(fqdn_len - 4);
 217         fqdn.flags = 0;
 218
 219
 220         // Build Client ID
 221         size_t cl_id_len;
 222         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 223
 224         // Get Server ID
 225         size_t srv_id_len;
 226         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 227
 228         // Build IA_PDs
 229         size_t ia_pd_entries, ia_pd_len = 0;
 230         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 231         ia_pd_entries /= sizeof(*e);
 232         struct dhcpv6_ia_hdr hdr_ia_pd = {
 233                 htons(DHCPV6_OPT_IA_PD),
 234                 htons(sizeof(hdr_ia_pd) - 4),
 235                 1, 0, 0
 236         };
 237
 238
 239         uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
 240         for (size_t i = 0; i < ia_pd_entries; ++i) {
 241                 uint8_t ex_len = 0;
 242                 if (e[i].priority > 0)
 243                         ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
 244
 245                 struct dhcpv6_ia_prefix p = {
 246                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 247                         .len = htons(sizeof(p) - 4U + ex_len),
 248                         .prefix = e[i].length,
 249                         .addr = e[i].target
 250                 };
 251
 252                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 253                 ia_pd_len += sizeof(p);
 254
 255                 if (ex_len) {
 256                         ia_pd[ia_pd_len++] = 0;
 257                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 258                         ia_pd[ia_pd_len++] = 0;
 259                         ia_pd[ia_pd_len++] = ex_len - 4;
 260                         ia_pd[ia_pd_len++] = e[i].priority;
 261
 262                         uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
 263                         excl >>= (64 - e[i].priority);
 264                         excl <<= 8 - ((e[i].priority - e[i].length) % 8);
 265
 266                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 267                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 268                         ia_pd_len += ex_len - 5;
 269                 }
 270         }
 271
 272         struct dhcpv6_ia_prefix pref = {
 273                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 274                 .len = htons(25), .prefix = request_prefix
 275         };
 276         if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
 277                 ia_pd = (uint8_t*)&pref;
 278                 ia_pd_len = sizeof(pref);
 279         }
 280         hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
 281
 282         // Build IA_NAs
 283         size_t ia_na_entries, ia_na_len = 0;
 284         void *ia_na = NULL;
 285         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 286         ia_na_entries /= sizeof(*e);
 287
 288         struct dhcpv6_ia_hdr hdr_ia_na = {
 289                 htons(DHCPV6_OPT_IA_NA),
 290                 htons(sizeof(hdr_ia_na) - 4),
 291                 1, 0, 0
 292         };
 293
 294         struct dhcpv6_ia_addr pa[ia_na_entries];
 295         for (size_t i = 0; i < ia_na_entries; ++i) {
 296                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 297                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 298                 pa[i].addr = e[i].target;
 299                 pa[i].preferred = 0;
 300                 pa[i].valid = 0;
 301         }
 302
 303         ia_na = pa;
 304         ia_na_len = sizeof(pa);
 305         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 306
 307         // Reconfigure Accept
 308         struct {
 309                 uint16_t type;
 310                 uint16_t length;
 311         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 312
 313         // Request Information Refresh
 314         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 315
 316         // Prepare Header
 317         size_t oro_len;
 318         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 319         struct {
 320                 uint8_t type;
 321                 uint8_t trid[3];
 322                 uint16_t elapsed_type;
 323                 uint16_t elapsed_len;
 324                 uint16_t elapsed_value;
 325                 uint16_t oro_type;
 326                 uint16_t oro_len;
 327         } hdr = {
 328                 type, {trid[0], trid[1], trid[2]},
 329                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 330                         htons((ecs > 0xffff) ? 0xffff : ecs),
 331                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 332         };
 333
 334         struct iovec iov[] = {
 335                 {&hdr, sizeof(hdr)},
 336                 {oro, oro_len},
 337                 {&oro_refresh, 0},
 338                 {cl_id, cl_id_len},
 339                 {srv_id, srv_id_len},
 340                 {&reconf_accept, sizeof(reconf_accept)},
 341                 {&fqdn, fqdn_len},
 342                 {&hdr_ia_na, sizeof(hdr_ia_na)},
 343                 {ia_na, ia_na_len},
 344                 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
 345                 {ia_pd, ia_pd_len},
 346         };
 347
 348         size_t cnt = ARRAY_SIZE(iov);
 349         if (type == DHCPV6_MSG_INFO_REQ) {
 350                 cnt = 5;
 351                 iov[2].iov_len = sizeof(oro_refresh);
 352                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 353         } else if (!request_prefix) {
 354                 cnt = 9;
 355         }
 356
 357         // Disable IAs if not used
 358         if (type != DHCPV6_MSG_SOLICIT) {
 359                 iov[5].iov_len = 0;
 360                 if (ia_na_len == 0)
 361                         iov[7].iov_len = 0;
 362                 if (ia_pd_len == 0)
 363                         iov[9].iov_len = 0;
 364         }
 365
 366         if (na_mode == IA_MODE_NONE)
 367                 iov[7].iov_len = 0;
 368
 369         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 370                 0, ALL_DHCPV6_RELAYS, ifindex};
 371         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 372
 373         sendmsg(sock, &msg, 0);
 374 }
 375
 376
 377 static int64_t dhcpv6_rand_delay(int64_t time)
 378 {
 379         int random;
 380         odhcp6c_random(&random, sizeof(random));
 381         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 382 }
 383
 384
 385 int dhcpv6_request(enum dhcpv6_msg type)
 386 {
 387         uint8_t rc = 0;
 388         uint64_t timeout = UINT32_MAX;
 389         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 390
 391         if (retx->delay) {
 392                 struct timespec ts = {0, 0};
 393                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 394                 nanosleep(&ts, NULL);
 395         }
 396
 397         if (type == DHCPV6_MSG_UNKNOWN)
 398                 timeout = t1;
 399         else if (type == DHCPV6_MSG_RENEW)
 400                 timeout = (t2 > t1) ? t2 - t1 : 0;
 401         else if (type == DHCPV6_MSG_REBIND)
 402                 timeout = (t3 > t2) ? t3 - t2 : 0;
 403
 404         if (timeout == 0)
 405                 return -1;
 406
 407         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 408                         retx->name, (unsigned long long)timeout, retx->max_rc);
 409
 410         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 411
 412         // Generate transaction ID
 413         uint8_t trid[3] = {0, 0, 0};
 414         if (type != DHCPV6_MSG_UNKNOWN)
 415                 odhcp6c_random(trid, sizeof(trid));
 416         ssize_t len = -1;
 417         int64_t rto = 0;
 418
 419         do {
 420                 if (rto == 0) {
 421                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 422
 423                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 424                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 425                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 426
 427                         rto = (retx->init_timeo * 1000 + delay);
 428                 }
 429                 else
 430                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 431
 432                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 433                         rto = retx->max_timeo * 1000 +
 434                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 435
 436                 // Calculate end for this round and elapsed time
 437                 uint64_t round_end = round_start + rto;
 438                 elapsed = round_start - start;
 439
 440                 // Don't wait too long
 441                 if (round_end - start > timeout * 1000)
 442                         round_end = timeout * 1000 + start;
 443
 444                 // Built and send package
 445                 if (type != DHCPV6_MSG_UNKNOWN) {
 446                         if (type != DHCPV6_MSG_SOLICIT)
 447                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 448                                                 retx->name, (unsigned long long)elapsed, rc);
 449                         dhcpv6_send(type, trid, elapsed / 10);
 450                         rc++;
 451                 }
 452
 453                 // Receive rounds
 454                 for (; len < 0 && (round_start < round_end);
 455                                 round_start = odhcp6c_get_milli_time()) {
 456                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 457                         struct iovec iov = {buf, sizeof(buf)};
 458                         struct msghdr msg = {NULL, 0, &iov, 1,
 459                                         cmsg_buf, sizeof(cmsg_buf), 0};
 460                         struct in6_pktinfo *pktinfo = NULL;
 461
 462                         // Check for pending signal
 463                         if (odhcp6c_signal_process())
 464                                 return -1;
 465
 466                         // Set timeout for receiving
 467                         uint64_t t = round_end - round_start;
 468                         struct timeval timeout = {t / 1000, (t % 1000) * 1000};
 469                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 470                                         &timeout, sizeof(timeout));
 471
 472                         // Receive cycle
 473                         len = recvmsg(sock, &msg, 0);
 474                         if (len < 0)
 475                                 continue;
 476
 477                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 478                                 ch = CMSG_NXTHDR(&msg, ch)) {
 479                                 if (ch->cmsg_level == SOL_IPV6 &&
 480                                         ch->cmsg_type == IPV6_PKTINFO) {
 481                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 482                                         break;
 483                                 }
 484                         }
 485
 486                         if (pktinfo == NULL) {
 487                                 len = -1;
 488                                 continue;
 489                         }
 490
 491                         if (!dhcpv6_response_is_valid(buf, len, trid,
 492                                                         type, &pktinfo->ipi6_addr)) {
 493                                 len = -1;
 494                                 continue;
 495                         }
 496
 497                         uint8_t *opt = &buf[4];
 498                         uint8_t *opt_end = opt + len - 4;
 499
 500                         round_start = odhcp6c_get_milli_time();
 501                         elapsed = round_start - start;
 502                         syslog(LOG_NOTICE, "Got a valid reply after "
 503                                         "%llums", (unsigned long long)elapsed);
 504
 505                         if (retx->handler_reply)
 506                                 len = retx->handler_reply(type, rc, opt, opt_end);
 507
 508                         if (len > 0 && round_end - round_start > 1000)
 509                                 round_end = 1000 + round_start;
 510                 }
 511
 512                 // Allow
 513                 if (retx->handler_finish)
 514                         len = retx->handler_finish();
 515         } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
 516
 517         return len;
 518 }
 519
 520 // Message validation checks according to RFC3315 chapter 15
 521 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 522                 const uint8_t transaction[3], enum dhcpv6_msg type,
 523                 const struct in6_addr *daddr)
 524 {
 525         const struct dhcpv6_header *rep = buf;
 526         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 527                         transaction, sizeof(rep->tr_id)))
 528                 return false; // Invalid reply
 529
 530         if (type == DHCPV6_MSG_SOLICIT) {
 531                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 532                                 rep->msg_type != DHCPV6_MSG_REPLY)
 533                         return false;
 534         } else if (type == DHCPV6_MSG_UNKNOWN) {
 535                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 536                         return false;
 537         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 538                 return false;
 539         }
 540
 541         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 542                 rcmsg = DHCPV6_MSG_UNKNOWN;
 543         uint16_t otype, olen = UINT16_MAX;
 544         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 545                 ia_present = false, options_valid = true;
 546
 547         size_t client_id_len, server_id_len;
 548         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 549         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 550
 551         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 552                 if (otype == DHCPV6_OPT_CLIENTID) {
 553                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 554                                         &odata[-4], client_id, client_id_len);
 555                 } else if (otype == DHCPV6_OPT_SERVERID) {
 556                         if (server_id_len)
 557                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 558                                                 &odata[-4], server_id, server_id_len);
 559                         else
 560                                 serverid_ok = true;
 561                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 562                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 563                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 564                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 565                                 continue;
 566
 567                         md5_state_t md5;
 568                         uint8_t serverhash[16], secretbytes[16], hash[16];
 569                         memcpy(serverhash, r->key, sizeof(serverhash));
 570                         memset(r->key, 0, sizeof(r->key));
 571                         memcpy(secretbytes, reconf_key, sizeof(secretbytes));
 572
 573                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 574                                 secretbytes[i] ^= 0x36;
 575
 576                         md5_init(&md5);
 577                         md5_append(&md5, secretbytes, sizeof(secretbytes));
 578                         md5_append(&md5, buf, len);
 579                         md5_finish(&md5, hash);
 580
 581                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 582                                 secretbytes[i] ^= 0x36;
 583                                 secretbytes[i] ^= 0x5c;
 584                         }
 585
 586                         md5_init(&md5);
 587                         md5_append(&md5, secretbytes, sizeof(secretbytes));
 588                         md5_append(&md5, hash, 16);
 589                         md5_finish(&md5, hash);
 590
 591                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 592                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 593                         rcmsg = odata[0];
 594                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 595                         ia_present = true;
 596                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 597                                 options_valid = false;
 598                 }
 599                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 600                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 601                         // Options are not allowed on global level
 602                         options_valid = false;
 603                 }
 604         }
 605
 606         if (!options_valid || ((odata + olen) > end))
 607                 return false;
 608
 609         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 610                 return false;
 611
 612         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 613                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 614                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 615                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 616                         return false;
 617         }
 618
 619         return clientid_ok && serverid_ok;
 620 }
 621
 622
 623 int dhcpv6_poll_reconfigure(void)
 624 {
 625         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 626         if (ret != -1)
 627                 ret = dhcpv6_request(ret);
 628
 629         return ret;
 630 }
 631
 632
 633 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 634                 const void *opt, const void *end)
 635 {
 636         uint16_t otype, olen;
 637         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 638         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 639                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 640                                 odata[0] == DHCPV6_MSG_RENEW ||
 641                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 642                         msg = odata[0];
 643
 644         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 645         return msg;
 646 }
 647
 648
 649 // Collect all advertised servers
 650 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 651                 const void *opt, const void *end)
 652 {
 653         uint16_t olen, otype;
 654         uint8_t *odata, pref = 0;
 655         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 656                                         DHCPV6_SOL_MAX_RT,
 657                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 658         bool have_na = false;
 659         int have_pd = 0;
 660
 661         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 662                 if (orig == DHCPV6_MSG_SOLICIT &&
 663                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 664                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 665                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 666                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 667                 }
 668
 669                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 670                         memcpy(cand.duid, odata, olen);
 671                         cand.duid_len = olen;
 672                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 673                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 674
 675                         switch (error) {
 676                         case DHCPV6_NoPrefixAvail:
 677                                 // Status code on global level
 678                                 cand.preference -= 2000;
 679                                 break;
 680
 681                         default :
 682                                 break;
 683                         }
 684                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 685                                 cand.preference >= 0) {
 686                         cand.preference = pref = odata[0];
 687                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 688                         cand.wants_reconfigure = true;
 689                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 690                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 691                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 692                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 693                                 cand.sol_max_rt = sol_max_rt;
 694                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 695                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 696                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 697                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 698                                 cand.inf_max_rt = inf_max_rt;
 699                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 700                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 701                         uint8_t *oend = odata + olen, *d;
 702                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 703                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 704                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 705                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 706                                         have_pd = p->prefix;
 707                                 }
 708                         }
 709                 } else if (otype == DHCPV6_OPT_IA_NA) {
 710                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 711                         uint8_t *oend = odata + olen, *d;
 712                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 713                                 if (otype == DHCPV6_OPT_IA_ADDR)
 714                                         have_na = true;
 715                 }
 716         }
 717
 718         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 719                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 720                 /*
 721                  * RFC7083 states to process the SOL_MAX_RT and
 722                  * INF_MAX_RT options even if the DHCPv6 server
 723                  * did not propose any IA_NA and/or IA_PD
 724                  */
 725                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 726                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 727                 return -1;
 728         }
 729
 730         if (na_mode != IA_MODE_NONE && !have_na) {
 731                 cand.has_noaddravail = true;
 732                 cand.preference -= 1000;
 733         }
 734
 735         if (pd_mode != IA_MODE_NONE) {
 736                 if (have_pd)
 737                         cand.preference += 2000 + (128 - have_pd);
 738                 else
 739                         cand.preference -= 2000;
 740         }
 741
 742         if (cand.duid_len > 0) {
 743                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 744                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 745                 dhcpv6_add_server_cand(&cand);
 746         }
 747
 748         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 749 }
 750
 751
 752 static int dhcpv6_commit_advert(void)
 753 {
 754         return dhcpv6_promote_server_cand();
 755 }
 756
 757
 758 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 759                 const void *opt, const void *end)
 760 {
 761         dhcpv6_handle_advert(orig, rc, opt, end);
 762         if (dhcpv6_commit_advert() < 0)
 763                 return -1;
 764
 765         return dhcpv6_handle_reply(orig, rc, opt, end);
 766 }
 767
 768
 769 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 770                 const void *opt, const void *end)
 771 {
 772         uint8_t *odata;
 773         uint16_t otype, olen;
 774         uint32_t refresh = UINT32_MAX;
 775         int ret = 1;
 776         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 777
 778         odhcp6c_expire();
 779
 780         if (orig == DHCPV6_MSG_UNKNOWN) {
 781                 static time_t last_update = 0;
 782                 time_t now = odhcp6c_get_milli_time() / 1000;
 783
 784                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 785                 last_update = now;
 786
 787                 t1 -= elapsed;
 788                 t2 -= elapsed;
 789                 t3 -= elapsed;
 790
 791                 if (t1 < 0)
 792                         t1 = 0;
 793
 794                 if (t2 < 0)
 795                         t2 = 0;
 796
 797                 if (t3 < 0)
 798                         t3 = 0;
 799         }
 800
 801         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 802                 // Delete NA and PD we have in the state from the Advert
 803                 odhcp6c_clear_state(STATE_IA_NA);
 804                 odhcp6c_clear_state(STATE_IA_PD);
 805         }
 806
 807         if (opt) {
 808                 odhcp6c_clear_state(STATE_DNS);
 809                 odhcp6c_clear_state(STATE_SEARCH);
 810                 odhcp6c_clear_state(STATE_SNTP_IP);
 811                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 812                 odhcp6c_clear_state(STATE_SIP_IP);
 813                 odhcp6c_clear_state(STATE_SIP_FQDN);
 814                 odhcp6c_clear_state(STATE_AFTR_NAME);
 815         }
 816
 817         // Parse and find all matching IAs
 818         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 819                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 820                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 821                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 822
 823                         // Test ID
 824                         if (ia_hdr->iaid != 1)
 825                                 continue;
 826
 827                         uint16_t code = DHCPV6_Success;
 828                         uint16_t stype, slen;
 829                         uint8_t *sdata;
 830                         // Get and handle status code
 831                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 832                                         stype, slen, sdata) {
 833                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 834                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 835                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 836
 837                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 838
 839                                         if (code == DHCPV6_Success)
 840                                                 continue;
 841
 842                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 843                                                 code, mdata, mlen, handled_status_codes, &ret);
 844
 845
 846                                         if (ret > 0)
 847                                                 return ret;
 848                                         break;
 849                                 }
 850                         }
 851
 852                         if (code != DHCPV6_Success)
 853                                 continue;
 854
 855                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 856                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 857                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 858                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 859                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 860
 861                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 862                 }
 863                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 864                         if (olen % 16 == 0)
 865                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 866                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 867                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 868                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 869                         uint16_t stype, slen;
 870                         uint8_t *sdata;
 871                         // Test status and bail if error
 872                         dhcpv6_for_each_option(odata, odata + olen,
 873                                         stype, slen, sdata) {
 874                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 875                                                 stype == NTP_SRV_ADDR))
 876                                         odhcp6c_add_state(STATE_SNTP_IP,
 877                                                         sdata, slen);
 878                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 879                                         odhcp6c_add_state(STATE_SNTP_FQDN,
 880                                                         sdata, slen);
 881                         }
 882                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 883                         if (olen == 16)
 884                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 885                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 886                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 887                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 888                         refresh = ntohl(*((uint32_t*)odata));
 889                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 890                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 891                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 892                         if (r->protocol == 3 && r->algorithm == 1 &&
 893                                         r->reconf_type == 1)
 894                                 memcpy(reconf_key, r->key, sizeof(r->key));
 895                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
 896                         size_t cur_len;
 897                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
 898                         if (cur_len == 0)
 899                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
 900                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 901                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 902                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 903                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 904                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
 905                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 906                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 907                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 908                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 909                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
 910                 }else if (otype != DHCPV6_OPT_CLIENTID &&
 911                                 otype != DHCPV6_OPT_SERVERID) {
 912                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
 913                                         &odata[-4], olen + 4);
 914                 }
 915         }
 916
 917         if (orig != DHCPV6_MSG_INFO_REQ) {
 918                 // Update refresh timers if no fatal status code was received
 919                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
 920                         switch (orig) {
 921                         case DHCPV6_MSG_RENEW:
 922                                 // Send further renews if T1 is not set
 923                                 if (!t1)
 924                                         ret = -1;
 925                                 break;
 926                         case DHCPV6_MSG_REBIND:
 927                                 // Send further rebinds if T1 and T2 is not set
 928                                 if (!t1 && !t2)
 929                                         ret = -1;
 930                                 break;
 931
 932                         case DHCPV6_MSG_REQUEST:
 933                                 // All server candidates can be cleared if not yet bound
 934                                 if (!odhcp6c_is_bound())
 935                                         dhcpv6_clear_all_server_cand();
 936
 937                         default :
 938                                 break;
 939                         }
 940                 }
 941         }
 942         else if (ret > 0) {
 943                 // All server candidates can be cleared if not yet bound
 944                 if (!odhcp6c_is_bound())
 945                         dhcpv6_clear_all_server_cand();
 946
 947                 t1 = refresh;
 948         }
 949
 950         return ret;
 951 }
 952
 953
 954 static int dhcpv6_parse_ia(void *opt, void *end)
 955 {
 956         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
 957         int parsed_ia = 0;
 958         uint32_t t1, t2;
 959         uint16_t otype, olen;
 960         uint8_t *odata;
 961
 962         t1 = ntohl(ia_hdr->t1);
 963         t2 = ntohl(ia_hdr->t2);
 964
 965         if (t1 > t2)
 966                 return 0;
 967
 968         // Update address IA
 969         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
 970                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
 971                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
 972
 973                 if (otype == DHCPV6_OPT_IA_PREFIX) {
 974                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
 975                         if (olen + 4U < sizeof(*prefix))
 976                                 continue;
 977
 978                         entry.valid = ntohl(prefix->valid);
 979                         entry.preferred = ntohl(prefix->preferred);
 980
 981                         if (entry.preferred > entry.valid)
 982                                 continue;
 983
 984                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
 985                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
 986                         if (entry.t1 > entry.t2)
 987                                 entry.t1 = entry.t2;
 988
 989                         entry.length = prefix->prefix;
 990                         entry.target = prefix->addr;
 991                         uint16_t stype, slen;
 992                         uint8_t *sdata;
 993
 994 #ifdef EXT_PREFIX_CLASS
 995                         // Find prefix class, if any
 996                         dhcpv6_for_each_option(&prefix[1], odata + olen,
 997                                         stype, slen, sdata)
 998                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
 999                                         entry.class = sdata[0] << 8 | sdata[1];
1000 #endif
1001
1002                         // Parse PD-exclude
1003                         bool ok = true;
1004                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1005                                         odata + olen, stype, slen, sdata) {
1006                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1007                                         continue;
1008
1009                                 uint8_t elen = sdata[0];
1010                                 if (elen > 64)
1011                                         elen = 64;
1012
1013                                 if (elen <= 32 || elen <= entry.length) {
1014                                         ok = false;
1015                                         continue;
1016                                 }
1017
1018
1019                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1020                                 if (slen <= bytes) {
1021                                         ok = false;
1022                                         continue;
1023                                 }
1024
1025                                 uint32_t exclude = 0;
1026                                 do {
1027                                         exclude = exclude << 8 | sdata[bytes];
1028                                 } while (--bytes);
1029
1030                                 exclude >>= 8 - ((elen - entry.length) % 8);
1031                                 exclude <<= 64 - elen;
1032
1033                                 // Abusing router & priority fields for exclusion
1034                                 entry.router = entry.target;
1035                                 entry.router.s6_addr32[1] |= htonl(exclude);
1036                                 entry.priority = elen;
1037                         }
1038
1039                         if (ok) {
1040                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1041                                 parsed_ia++;
1042                         }
1043
1044                         entry.priority = 0;
1045                         memset(&entry.router, 0, sizeof(entry.router));
1046                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1047                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1048                         if (olen + 4U < sizeof(*addr))
1049                                 continue;
1050
1051                         entry.preferred = ntohl(addr->preferred);
1052                         entry.valid = ntohl(addr->valid);
1053
1054                         if (entry.preferred > entry.valid)
1055                                 continue;
1056
1057                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1058                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1059                         if (entry.t1 > entry.t2)
1060                                 entry.t1 = entry.t2;
1061
1062                         entry.length = 128;
1063                         entry.target = addr->addr;
1064
1065 #ifdef EXT_PREFIX_CLASS
1066                         uint16_t stype, slen;
1067                         uint8_t *sdata;
1068                         // Find prefix class, if any
1069                         dhcpv6_for_each_option(&addr[1], odata + olen,
1070                                         stype, slen, sdata)
1071                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1072                                         entry.class = sdata[0] << 8 | sdata[1];
1073 #endif
1074
1075                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1076                         parsed_ia++;
1077                 }
1078         }
1079         return parsed_ia;
1080 }
1081
1082
1083 static int dhcpv6_calc_refresh_timers(void)
1084 {
1085         struct odhcp6c_entry *e;
1086         size_t ia_na_entries, ia_pd_entries, i;
1087         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1088
1089         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1090         ia_na_entries /= sizeof(*e);
1091         for (i = 0; i < ia_na_entries; i++) {
1092                 if (e[i].t1 < l_t1)
1093                         l_t1 = e[i].t1;
1094
1095                 if (e[i].t2 < l_t2)
1096                         l_t2 = e[i].t2;
1097
1098                 if (e[i].valid > l_t3)
1099                         l_t3 = e[i].valid;
1100         }
1101
1102         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1103         ia_pd_entries /= sizeof(*e);
1104         for (i = 0; i < ia_pd_entries; i++) {
1105                 if (e[i].t1 < l_t1)
1106                         l_t1 = e[i].t1;
1107
1108                 if (e[i].t2 < l_t2)
1109                         l_t2 = e[i].t2;
1110
1111                 if (e[i].valid > l_t3)
1112                         l_t3 = e[i].valid;
1113         }
1114
1115         if (ia_pd_entries || ia_na_entries) {
1116                 t1 = l_t1;
1117                 t2 = l_t2;
1118                 t3 = l_t3;
1119         } else {
1120                 t1 = 600;
1121         }
1122
1123         return (int)(ia_pd_entries + ia_na_entries);
1124 }
1125
1126
1127 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1128                 const void *status_msg, const int len)
1129 {
1130         uint8_t buf[len + 3];
1131
1132         memset(buf, 0, sizeof(buf));
1133         if (len) {
1134                 buf[0] = '(';
1135                 memcpy(&buf[1], status_msg, len);
1136                 buf[len + 1] = ')';
1137         }
1138
1139         syslog(LOG_WARNING, "Server returned %s status %i %s",
1140                 scope, code, buf);
1141 }
1142
1143
1144 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1145                 const uint16_t code, const void *status_msg, const int len,
1146                 int *ret)
1147 {
1148         dhcpv6_log_status_code(code, "message", status_msg, len);
1149
1150         switch (code) {
1151         case DHCPV6_UnspecFail:
1152                 // Generic failure
1153                 *ret = 0;
1154                 break;
1155
1156         case DHCPV6_UseMulticast:
1157                 // TODO handle multicast status code
1158                 break;
1159
1160         case DHCPV6_NoAddrsAvail:
1161         case DHCPV6_NoPrefixAvail:
1162                 if (orig == DHCPV6_MSG_REQUEST)
1163                         *ret = 0; // Failure
1164                 break;
1165
1166         default:
1167                 break;
1168         }
1169 }
1170
1171
1172 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1173                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1174                 const void *status_msg, const int len,
1175                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1176 {
1177         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1178                 "IA_NA" : "IA_PD", status_msg, len);
1179
1180         switch (code) {
1181         case DHCPV6_NoBinding:
1182                 switch (orig) {
1183                 case DHCPV6_MSG_RENEW:
1184                 case DHCPV6_MSG_REBIND:
1185                         if ((*ret > 0) && !handled_status_codes[code])
1186                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1187                         break;
1188
1189                 default:
1190                         break;
1191                 }
1192                 break;
1193
1194         case DHCPV6_NoAddrsAvail:
1195         case DHCPV6_NoPrefixAvail:
1196                 switch (orig) {
1197                 case DHCPV6_MSG_REQUEST:
1198                         if (*ret != 0)
1199                                 *ret = 0;
1200                         break;
1201                 default:
1202                         break;
1203                 }
1204                 break;
1205
1206         case DHCPV6_NotOnLink:
1207                 // TODO handle not onlink in case of confirm
1208                 break;
1209
1210         default:
1211                 break;
1212         }
1213 }
1214
1215 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1216 {
1217         size_t cand_len, i;
1218         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1219
1220         // Remove identical duid server candidate
1221         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1222                 if (cand->duid_len == c[i].duid_len &&
1223                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1224                         free(c[i].ia_na);
1225                         free(c[i].ia_pd);
1226                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1227                         break;
1228                 }
1229         }
1230
1231         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1232                 i < cand_len / sizeof(*c); ++i) {
1233                 if (c[i].preference < cand->preference)
1234                         break;
1235         }
1236
1237         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1238 }
1239
1240 static void dhcpv6_clear_all_server_cand(void)
1241 {
1242         size_t cand_len, i;
1243         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1244
1245         // Server candidates need deep delete for IA_NA/IA_PD
1246         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1247                 free(c[i].ia_na);
1248                 free(c[i].ia_pd);
1249         }
1250         odhcp6c_clear_state(STATE_SERVER_CAND);
1251 }
1252
1253 int dhcpv6_promote_server_cand(void)
1254 {
1255         size_t cand_len;
1256         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1257         uint16_t hdr[2];
1258         int ret = (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) ?
1259                         DHCPV6_STATELESS : DHCPV6_STATEFUL;
1260
1261         // Clear lingering candidate state info
1262         odhcp6c_clear_state(STATE_SERVER_ID);
1263         odhcp6c_clear_state(STATE_IA_NA);
1264         odhcp6c_clear_state(STATE_IA_PD);
1265
1266         if (!cand_len)
1267                 return -1;
1268
1269         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1270                 na_mode = IA_MODE_NONE;
1271
1272                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1273                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1274
1275                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1276         }
1277
1278         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1279         hdr[1] = htons(cand->duid_len);
1280         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1281         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1282         accept_reconfig = cand->wants_reconfigure;
1283         if (cand->ia_na_len) {
1284                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1285                 free(cand->ia_na);
1286                 if (na_mode != IA_MODE_NONE)
1287                         ret = DHCPV6_STATEFUL;
1288         }
1289         if (cand->ia_pd_len) {
1290                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1291                 free(cand->ia_pd);
1292                 if (request_prefix)
1293                         ret = DHCPV6_STATEFUL;
1294         }
1295
1296         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1297         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1298
1299         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1300
1301         return ret;
1302 }