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 // client options
 109 static unsigned int client_options = 0;
 110
 111
 112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 113 {
 114         client_options = options;
 115         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 116
 117         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 118         if (sock < 0)
 119                 return -1;
 120
 121         // Detect interface
 122         struct ifreq ifr;
 123         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 124         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 125                 return -1;
 126         ifindex = ifr.ifr_ifindex;
 127
 128         // Create client DUID
 129         size_t client_id_len;
 130         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 131         if (client_id_len == 0) {
 132                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 133                                 DHCPV6_DUID_LLADDR, 0, 1};
 134
 135                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 136                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 137
 138                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 139                 struct ifreq ifs[100], *ifp, *ifend;
 140                 struct ifconf ifc;
 141                 ifc.ifc_req = ifs;
 142                 ifc.ifc_len = sizeof(ifs);
 143
 144                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 145                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 146                         // If our interface doesn't have an address...
 147                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 148                         for (ifp = ifc.ifc_req; ifp < ifend &&
 149                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 150                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 151                                                 sizeof(ifr.ifr_name));
 152                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 153                                         continue;
 154
 155                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 156                                                 ETHER_ADDR_LEN);
 157                         }
 158                 }
 159
 160                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 161         }
 162
 163         // Create ORO
 164         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 165                 uint16_t oro[] = {
 166                         htons(DHCPV6_OPT_SIP_SERVER_D),
 167                         htons(DHCPV6_OPT_SIP_SERVER_A),
 168                         htons(DHCPV6_OPT_DNS_SERVERS),
 169                         htons(DHCPV6_OPT_DNS_DOMAIN),
 170                         htons(DHCPV6_OPT_SNTP_SERVERS),
 171                         htons(DHCPV6_OPT_NTP_SERVER),
 172                         htons(DHCPV6_OPT_AFTR_NAME),
 173                         htons(DHCPV6_OPT_PD_EXCLUDE),
 174                         htons(DHCPV6_OPT_SOL_MAX_RT),
 175                         htons(DHCPV6_OPT_INF_MAX_RT),
 176 #ifdef EXT_PREFIX_CLASS
 177                         htons(DHCPV6_OPT_PREFIX_CLASS),
 178 #endif
 179                 };
 180                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 181         }
 182
 183         // Configure IPv6-options
 184         int val = 1;
 185         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 186         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 187         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 188         val = 0;
 189         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
 190         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 191
 192         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 193                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 194         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 195                 return -1;
 196
 197         return 0;
 198 }
 199
 200
 201 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 202 {
 203         na_mode = na;
 204         pd_mode = pd;
 205 }
 206
 207 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 208 {
 209         // Build FQDN
 210         char fqdn_buf[256];
 211         gethostname(fqdn_buf, sizeof(fqdn_buf));
 212         struct {
 213                 uint16_t type;
 214                 uint16_t len;
 215                 uint8_t flags;
 216                 uint8_t data[256];
 217         } fqdn;
 218         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 219                         sizeof(fqdn.data), NULL, NULL);
 220         fqdn.type = htons(DHCPV6_OPT_FQDN);
 221         fqdn.len = htons(fqdn_len - 4);
 222         fqdn.flags = 0;
 223
 224
 225         // Build Client ID
 226         size_t cl_id_len;
 227         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 228
 229         // Get Server ID
 230         size_t srv_id_len;
 231         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 232
 233         // Build IA_PDs
 234         size_t ia_pd_entries, ia_pd_len = 0;
 235         uint8_t *ia_pd;
 236
 237         if (type == DHCPV6_MSG_SOLICIT) {
 238                 odhcp6c_clear_state(STATE_IA_PD);
 239                 size_t n_prefixes;
 240                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 241                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 242
 243                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 244
 245                 for (size_t i = 0; i < n_prefixes; i++) {
 246                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 247                                 htons(DHCPV6_OPT_IA_PD),
 248                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 249                                 request_prefixes[i].iaid, 0, 0
 250                         };
 251                         struct dhcpv6_ia_prefix pref = {
 252                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 253                                 .len = htons(25), .prefix = request_prefixes[i].length
 254                         };
 255                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 256                         ia_pd_len += sizeof(hdr_ia_pd);
 257                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 258                         ia_pd_len += sizeof(pref);
 259                 }
 260         } else {
 261                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 262                 ia_pd_entries /= sizeof(*e);
 263
 264                 // we're too lazy to count our distinct IAIDs,
 265                 // so just allocate maximally needed space
 266                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 267                                         sizeof(struct dhcpv6_ia_hdr)));
 268
 269                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 270                         uint32_t iaid = e[i].iaid;
 271
 272                         // check if this is an unprocessed IAID and skip if not.
 273                         int new_iaid = 1;
 274                         for (int j = i-1; j >= 0; j--) {
 275                                 if (e[j].iaid == iaid) {
 276                                         new_iaid = 0;
 277                                         break;
 278                                 }
 279                         }
 280
 281                         if (!new_iaid)
 282                                 continue;
 283
 284                         // construct header
 285                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 286                                 htons(DHCPV6_OPT_IA_PD),
 287                                 htons(sizeof(hdr_ia_pd) - 4),
 288                                 iaid, 0, 0
 289                         };
 290
 291                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 292                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 293                         ia_pd_len += sizeof(hdr_ia_pd);
 294
 295                         for (size_t j = i; j < ia_pd_entries; j++) {
 296                                 if (e[j].iaid != iaid)
 297                                         continue;
 298
 299                                 uint8_t ex_len = 0;
 300                                 if (e[j].priority > 0)
 301                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 302
 303                                 struct dhcpv6_ia_prefix p = {
 304                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 305                                         .len = htons(sizeof(p) - 4U + ex_len),
 306                                         .prefix = e[j].length,
 307                                         .addr = e[j].target
 308                                 };
 309
 310                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 311                                 ia_pd_len += sizeof(p);
 312
 313                                 if (ex_len) {
 314                                         ia_pd[ia_pd_len++] = 0;
 315                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 316                                         ia_pd[ia_pd_len++] = 0;
 317                                         ia_pd[ia_pd_len++] = ex_len - 4;
 318                                         ia_pd[ia_pd_len++] = e[j].priority;
 319
 320                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 321                                         excl >>= (64 - e[j].priority);
 322                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 323
 324                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 325                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 326                                         ia_pd_len += ex_len - 5;
 327                                 }
 328
 329                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 330                         }
 331                 }
 332         }
 333
 334         if (ia_pd_entries > 0)
 335                 request_prefix = 1;
 336
 337         // Build IA_NAs
 338         size_t ia_na_entries, ia_na_len = 0;
 339         void *ia_na = NULL;
 340         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 341         ia_na_entries /= sizeof(*e);
 342
 343         struct dhcpv6_ia_hdr hdr_ia_na = {
 344                 htons(DHCPV6_OPT_IA_NA),
 345                 htons(sizeof(hdr_ia_na) - 4),
 346                 1, 0, 0
 347         };
 348
 349         struct dhcpv6_ia_addr pa[ia_na_entries];
 350         for (size_t i = 0; i < ia_na_entries; ++i) {
 351                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 352                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 353                 pa[i].addr = e[i].target;
 354                 pa[i].preferred = 0;
 355                 pa[i].valid = 0;
 356         }
 357
 358         ia_na = pa;
 359         ia_na_len = sizeof(pa);
 360         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 361
 362         // Reconfigure Accept
 363         struct {
 364                 uint16_t type;
 365                 uint16_t length;
 366         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 367
 368         // Request Information Refresh
 369         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 370
 371         // Prepare Header
 372         size_t oro_len;
 373         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 374         struct {
 375                 uint8_t type;
 376                 uint8_t trid[3];
 377                 uint16_t elapsed_type;
 378                 uint16_t elapsed_len;
 379                 uint16_t elapsed_value;
 380                 uint16_t oro_type;
 381                 uint16_t oro_len;
 382         } hdr = {
 383                 type, {trid[0], trid[1], trid[2]},
 384                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 385                         htons((ecs > 0xffff) ? 0xffff : ecs),
 386                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 387         };
 388
 389         struct iovec iov[] = {
 390                 {&hdr, sizeof(hdr)},
 391                 {oro, oro_len},
 392                 {&oro_refresh, 0},
 393                 {cl_id, cl_id_len},
 394                 {srv_id, srv_id_len},
 395                 {&reconf_accept, sizeof(reconf_accept)},
 396                 {&fqdn, fqdn_len},
 397                 {&hdr_ia_na, sizeof(hdr_ia_na)},
 398                 {ia_na, ia_na_len},
 399                 {ia_pd, ia_pd_len},
 400         };
 401
 402         size_t cnt = ARRAY_SIZE(iov);
 403         if (type == DHCPV6_MSG_INFO_REQ) {
 404                 cnt = 5;
 405                 iov[2].iov_len = sizeof(oro_refresh);
 406                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 407         } else if (!request_prefix) {
 408                 cnt = 9;
 409         }
 410
 411         // Disable IAs if not used
 412         if (type != DHCPV6_MSG_SOLICIT) {
 413                 iov[5].iov_len = 0;
 414                 if (ia_na_len == 0)
 415                         iov[7].iov_len = 0;
 416         }
 417
 418         if (na_mode == IA_MODE_NONE)
 419                 iov[7].iov_len = 0;
 420
 421         if (!(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 422                 iov[5].iov_len = 0;
 423
 424         if (!(client_options & DHCPV6_CLIENT_FQDN))
 425                 iov[6].iov_len = 0;
 426
 427         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 428                 0, ALL_DHCPV6_RELAYS, ifindex};
 429         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 430
 431         sendmsg(sock, &msg, 0);
 432 }
 433
 434
 435 static int64_t dhcpv6_rand_delay(int64_t time)
 436 {
 437         int random;
 438         odhcp6c_random(&random, sizeof(random));
 439         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 440 }
 441
 442
 443 int dhcpv6_request(enum dhcpv6_msg type)
 444 {
 445         uint8_t rc = 0;
 446         uint64_t timeout = UINT32_MAX;
 447         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 448
 449         if (retx->delay) {
 450                 struct timespec ts = {0, 0};
 451                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 452                 nanosleep(&ts, NULL);
 453         }
 454
 455         if (type == DHCPV6_MSG_UNKNOWN)
 456                 timeout = t1;
 457         else if (type == DHCPV6_MSG_RENEW)
 458                 timeout = (t2 > t1) ? t2 - t1 : 0;
 459         else if (type == DHCPV6_MSG_REBIND)
 460                 timeout = (t3 > t2) ? t3 - t2 : 0;
 461
 462         if (timeout == 0)
 463                 return -1;
 464
 465         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 466                         retx->name, (unsigned long long)timeout, retx->max_rc);
 467
 468         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 469
 470         // Generate transaction ID
 471         uint8_t trid[3] = {0, 0, 0};
 472         if (type != DHCPV6_MSG_UNKNOWN)
 473                 odhcp6c_random(trid, sizeof(trid));
 474         ssize_t len = -1;
 475         int64_t rto = 0;
 476
 477         do {
 478                 if (rto == 0) {
 479                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 480
 481                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 482                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 483                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 484
 485                         rto = (retx->init_timeo * 1000 + delay);
 486                 }
 487                 else
 488                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 489
 490                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 491                         rto = retx->max_timeo * 1000 +
 492                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 493
 494                 // Calculate end for this round and elapsed time
 495                 uint64_t round_end = round_start + rto;
 496                 elapsed = round_start - start;
 497
 498                 // Don't wait too long
 499                 if (round_end - start > timeout * 1000)
 500                         round_end = timeout * 1000 + start;
 501
 502                 // Built and send package
 503                 if (type != DHCPV6_MSG_UNKNOWN) {
 504                         if (type != DHCPV6_MSG_SOLICIT)
 505                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 506                                                 retx->name, (unsigned long long)elapsed, rc);
 507                         dhcpv6_send(type, trid, elapsed / 10);
 508                         rc++;
 509                 }
 510
 511                 // Receive rounds
 512                 for (; len < 0 && (round_start < round_end);
 513                                 round_start = odhcp6c_get_milli_time()) {
 514                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 515                         struct iovec iov = {buf, sizeof(buf)};
 516                         struct msghdr msg = {NULL, 0, &iov, 1,
 517                                         cmsg_buf, sizeof(cmsg_buf), 0};
 518                         struct in6_pktinfo *pktinfo = NULL;
 519
 520                         // Check for pending signal
 521                         if (odhcp6c_signal_process())
 522                                 return -1;
 523
 524                         // Set timeout for receiving
 525                         uint64_t t = round_end - round_start;
 526                         struct timeval timeout = {t / 1000, (t % 1000) * 1000};
 527                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 528                                         &timeout, sizeof(timeout));
 529
 530                         // Receive cycle
 531                         len = recvmsg(sock, &msg, 0);
 532                         if (len < 0)
 533                                 continue;
 534
 535                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 536                                 ch = CMSG_NXTHDR(&msg, ch)) {
 537                                 if (ch->cmsg_level == SOL_IPV6 &&
 538                                         ch->cmsg_type == IPV6_PKTINFO) {
 539                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 540                                         break;
 541                                 }
 542                         }
 543
 544                         if (pktinfo == NULL) {
 545                                 len = -1;
 546                                 continue;
 547                         }
 548
 549                         if (!dhcpv6_response_is_valid(buf, len, trid,
 550                                                         type, &pktinfo->ipi6_addr)) {
 551                                 len = -1;
 552                                 continue;
 553                         }
 554
 555                         uint8_t *opt = &buf[4];
 556                         uint8_t *opt_end = opt + len - 4;
 557
 558                         round_start = odhcp6c_get_milli_time();
 559                         elapsed = round_start - start;
 560                         syslog(LOG_NOTICE, "Got a valid reply after "
 561                                         "%llums", (unsigned long long)elapsed);
 562
 563                         if (retx->handler_reply)
 564                                 len = retx->handler_reply(type, rc, opt, opt_end);
 565
 566                         if (len > 0 && round_end - round_start > 1000)
 567                                 round_end = 1000 + round_start;
 568                 }
 569
 570                 // Allow
 571                 if (retx->handler_finish)
 572                         len = retx->handler_finish();
 573         } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
 574
 575         return len;
 576 }
 577
 578 // Message validation checks according to RFC3315 chapter 15
 579 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 580                 const uint8_t transaction[3], enum dhcpv6_msg type,
 581                 const struct in6_addr *daddr)
 582 {
 583         const struct dhcpv6_header *rep = buf;
 584         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 585                         transaction, sizeof(rep->tr_id)))
 586                 return false; // Invalid reply
 587
 588         if (type == DHCPV6_MSG_SOLICIT) {
 589                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 590                                 rep->msg_type != DHCPV6_MSG_REPLY)
 591                         return false;
 592         } else if (type == DHCPV6_MSG_UNKNOWN) {
 593                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 594                         return false;
 595         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 596                 return false;
 597         }
 598
 599         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 600                 rcmsg = DHCPV6_MSG_UNKNOWN;
 601         uint16_t otype, olen = UINT16_MAX;
 602         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 603                 ia_present = false, options_valid = true;
 604
 605         size_t client_id_len, server_id_len;
 606         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 607         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 608
 609         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 610                 if (otype == DHCPV6_OPT_CLIENTID) {
 611                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 612                                         &odata[-4], client_id, client_id_len);
 613                 } else if (otype == DHCPV6_OPT_SERVERID) {
 614                         if (server_id_len)
 615                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 616                                                 &odata[-4], server_id, server_id_len);
 617                         else
 618                                 serverid_ok = true;
 619                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 620                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 621                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 622                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 623                                 continue;
 624
 625                         md5_ctx_t md5;
 626                         uint8_t serverhash[16], secretbytes[16], hash[16];
 627                         memcpy(serverhash, r->key, sizeof(serverhash));
 628                         memset(r->key, 0, sizeof(r->key));
 629                         memcpy(secretbytes, reconf_key, sizeof(secretbytes));
 630
 631                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 632                                 secretbytes[i] ^= 0x36;
 633
 634                         md5_begin(&md5);
 635                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 636                         md5_hash(buf, len, &md5);
 637                         md5_end(hash, &md5);
 638
 639                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 640                                 secretbytes[i] ^= 0x36;
 641                                 secretbytes[i] ^= 0x5c;
 642                         }
 643
 644                         md5_begin(&md5);
 645                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 646                         md5_hash(hash, 16, &md5);
 647                         md5_end(hash, &md5);
 648
 649                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 650                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 651                         rcmsg = odata[0];
 652                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 653                         ia_present = true;
 654                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 655                                 options_valid = false;
 656                 }
 657                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 658                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 659                         // Options are not allowed on global level
 660                         options_valid = false;
 661                 }
 662         }
 663
 664         if (!options_valid || ((odata + olen) > end))
 665                 return false;
 666
 667         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 668                 return false;
 669
 670         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 671                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 672                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 673                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 674                         return false;
 675         }
 676
 677         return clientid_ok && serverid_ok;
 678 }
 679
 680
 681 int dhcpv6_poll_reconfigure(void)
 682 {
 683         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 684         if (ret != -1)
 685                 ret = dhcpv6_request(ret);
 686
 687         return ret;
 688 }
 689
 690
 691 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 692                 const void *opt, const void *end)
 693 {
 694         uint16_t otype, olen;
 695         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 696         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 697                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 698                                 odata[0] == DHCPV6_MSG_RENEW ||
 699                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 700                         msg = odata[0];
 701
 702         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 703         return msg;
 704 }
 705
 706
 707 // Collect all advertised servers
 708 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 709                 const void *opt, const void *end)
 710 {
 711         uint16_t olen, otype;
 712         uint8_t *odata, pref = 0;
 713         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 714                                         DHCPV6_SOL_MAX_RT,
 715                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 716         bool have_na = false;
 717         int have_pd = 0;
 718
 719         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 720                 if (orig == DHCPV6_MSG_SOLICIT &&
 721                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 722                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 723                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 724                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 725                 }
 726
 727                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 728                         memcpy(cand.duid, odata, olen);
 729                         cand.duid_len = olen;
 730                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 731                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 732
 733                         switch (error) {
 734                         case DHCPV6_NoPrefixAvail:
 735                                 // Status code on global level
 736                                 cand.preference -= 2000;
 737                                 break;
 738
 739                         default :
 740                                 break;
 741                         }
 742                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 743                                 cand.preference >= 0) {
 744                         cand.preference = pref = odata[0];
 745                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 746                         cand.wants_reconfigure = true;
 747                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 748                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 749                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 750                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 751                                 cand.sol_max_rt = sol_max_rt;
 752                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 753                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 754                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 755                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 756                                 cand.inf_max_rt = inf_max_rt;
 757                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 758                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 759                         uint8_t *oend = odata + olen, *d;
 760                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 761                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 762                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 763                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 764                                         have_pd = p->prefix;
 765                                 }
 766                         }
 767                 } else if (otype == DHCPV6_OPT_IA_NA) {
 768                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 769                         uint8_t *oend = odata + olen, *d;
 770                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 771                                 if (otype == DHCPV6_OPT_IA_ADDR)
 772                                         have_na = true;
 773                 }
 774         }
 775
 776         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 777                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 778                 /*
 779                  * RFC7083 states to process the SOL_MAX_RT and
 780                  * INF_MAX_RT options even if the DHCPv6 server
 781                  * did not propose any IA_NA and/or IA_PD
 782                  */
 783                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 784                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 785                 return -1;
 786         }
 787
 788         if (na_mode != IA_MODE_NONE && !have_na) {
 789                 cand.has_noaddravail = true;
 790                 cand.preference -= 1000;
 791         }
 792
 793         if (pd_mode != IA_MODE_NONE) {
 794                 if (have_pd)
 795                         cand.preference += 2000 + (128 - have_pd);
 796                 else
 797                         cand.preference -= 2000;
 798         }
 799
 800         if (cand.duid_len > 0) {
 801                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 802                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 803                 dhcpv6_add_server_cand(&cand);
 804         }
 805
 806         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 807 }
 808
 809
 810 static int dhcpv6_commit_advert(void)
 811 {
 812         return dhcpv6_promote_server_cand();
 813 }
 814
 815
 816 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 817                 const void *opt, const void *end)
 818 {
 819         dhcpv6_handle_advert(orig, rc, opt, end);
 820         if (dhcpv6_commit_advert() < 0)
 821                 return -1;
 822
 823         return dhcpv6_handle_reply(orig, rc, opt, end);
 824 }
 825
 826
 827 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 828                 const void *opt, const void *end)
 829 {
 830         uint8_t *odata;
 831         uint16_t otype, olen;
 832         uint32_t refresh = UINT32_MAX;
 833         int ret = 1;
 834         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 835
 836         odhcp6c_expire();
 837
 838         if (orig == DHCPV6_MSG_UNKNOWN) {
 839                 static time_t last_update = 0;
 840                 time_t now = odhcp6c_get_milli_time() / 1000;
 841
 842                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 843                 last_update = now;
 844
 845                 t1 -= elapsed;
 846                 t2 -= elapsed;
 847                 t3 -= elapsed;
 848
 849                 if (t1 < 0)
 850                         t1 = 0;
 851
 852                 if (t2 < 0)
 853                         t2 = 0;
 854
 855                 if (t3 < 0)
 856                         t3 = 0;
 857         }
 858
 859         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 860                 // Delete NA and PD we have in the state from the Advert
 861                 odhcp6c_clear_state(STATE_IA_NA);
 862                 odhcp6c_clear_state(STATE_IA_PD);
 863         }
 864
 865         if (opt) {
 866                 odhcp6c_clear_state(STATE_DNS);
 867                 odhcp6c_clear_state(STATE_SEARCH);
 868                 odhcp6c_clear_state(STATE_SNTP_IP);
 869                 odhcp6c_clear_state(STATE_NTP_IP);
 870                 odhcp6c_clear_state(STATE_NTP_FQDN);
 871                 odhcp6c_clear_state(STATE_SIP_IP);
 872                 odhcp6c_clear_state(STATE_SIP_FQDN);
 873                 odhcp6c_clear_state(STATE_AFTR_NAME);
 874         }
 875
 876         // Parse and find all matching IAs
 877         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 878                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 879                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 880                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 881
 882                         // Test ID
 883                         if (ia_hdr->iaid != 1 && otype == DHCPV6_OPT_IA_NA)
 884                                 continue;
 885
 886                         uint16_t code = DHCPV6_Success;
 887                         uint16_t stype, slen;
 888                         uint8_t *sdata;
 889                         // Get and handle status code
 890                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 891                                         stype, slen, sdata) {
 892                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 893                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 894                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 895
 896                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 897
 898                                         if (code == DHCPV6_Success)
 899                                                 continue;
 900
 901                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 902                                                 code, mdata, mlen, handled_status_codes, &ret);
 903
 904
 905                                         if (ret > 0)
 906                                                 return ret;
 907                                         break;
 908                                 }
 909                         }
 910
 911                         if (code != DHCPV6_Success)
 912                                 continue;
 913
 914                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 915                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 916                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 917                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 918                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 919
 920                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 921                 }
 922                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 923                         if (olen % 16 == 0)
 924                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 925                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 926                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 927                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 928                         if (olen % 16 == 0)
 929                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 930                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 931                         uint16_t stype, slen;
 932                         uint8_t *sdata;
 933                         // Test status and bail if error
 934                         dhcpv6_for_each_option(odata, odata + olen,
 935                                         stype, slen, sdata) {
 936                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 937                                                 stype == NTP_SRV_ADDR))
 938                                         odhcp6c_add_state(STATE_NTP_IP,
 939                                                         sdata, slen);
 940                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 941                                         odhcp6c_add_state(STATE_NTP_FQDN,
 942                                                         sdata, slen);
 943                         }
 944                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 945                         if (olen == 16)
 946                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 947                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 948                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 949                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 950                         refresh = ntohl(*((uint32_t*)odata));
 951                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 952                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 953                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 954                         if (r->protocol == 3 && r->algorithm == 1 &&
 955                                         r->reconf_type == 1)
 956                                 memcpy(reconf_key, r->key, sizeof(r->key));
 957                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
 958                         size_t cur_len;
 959                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
 960                         if (cur_len == 0)
 961                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
 962                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 963                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 964                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 965                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 966                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
 967                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 968                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 969                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 970                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 971                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
 972                 }else if (otype != DHCPV6_OPT_CLIENTID &&
 973                                 otype != DHCPV6_OPT_SERVERID) {
 974                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
 975                                         &odata[-4], olen + 4);
 976                 }
 977         }
 978
 979         if (orig != DHCPV6_MSG_INFO_REQ) {
 980                 // Update refresh timers if no fatal status code was received
 981                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
 982                         switch (orig) {
 983                         case DHCPV6_MSG_RENEW:
 984                                 // Send further renews if T1 is not set
 985                                 if (!t1)
 986                                         ret = -1;
 987                                 break;
 988                         case DHCPV6_MSG_REBIND:
 989                                 // Send further rebinds if T1 and T2 is not set
 990                                 if (!t1 && !t2)
 991                                         ret = -1;
 992                                 break;
 993
 994                         case DHCPV6_MSG_REQUEST:
 995                                 // All server candidates can be cleared if not yet bound
 996                                 if (!odhcp6c_is_bound())
 997                                         dhcpv6_clear_all_server_cand();
 998
 999                         default :
1000                                 break;
1001                         }
1002                 }
1003         }
1004         else if (ret > 0) {
1005                 // All server candidates can be cleared if not yet bound
1006                 if (!odhcp6c_is_bound())
1007                         dhcpv6_clear_all_server_cand();
1008
1009                 t1 = refresh;
1010         }
1011
1012         return ret;
1013 }
1014
1015
1016 static int dhcpv6_parse_ia(void *opt, void *end)
1017 {
1018         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1019         int parsed_ia = 0;
1020         uint32_t t1, t2;
1021         uint16_t otype, olen;
1022         uint8_t *odata;
1023
1024         t1 = ntohl(ia_hdr->t1);
1025         t2 = ntohl(ia_hdr->t2);
1026
1027         if (t1 > t2)
1028                 return 0;
1029
1030         // Update address IA
1031         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1032                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1033                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1034
1035                 entry.iaid = ia_hdr->iaid;
1036
1037                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1038                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1039                         if (olen + 4U < sizeof(*prefix))
1040                                 continue;
1041
1042                         entry.valid = ntohl(prefix->valid);
1043                         entry.preferred = ntohl(prefix->preferred);
1044
1045                         if (entry.preferred > entry.valid)
1046                                 continue;
1047
1048                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1049                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1050                         if (entry.t1 > entry.t2)
1051                                 entry.t1 = entry.t2;
1052
1053                         entry.length = prefix->prefix;
1054                         entry.target = prefix->addr;
1055                         uint16_t stype, slen;
1056                         uint8_t *sdata;
1057
1058 #ifdef EXT_PREFIX_CLASS
1059                         // Find prefix class, if any
1060                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1061                                         stype, slen, sdata)
1062                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1063                                         entry.class = sdata[0] << 8 | sdata[1];
1064 #endif
1065
1066                         // Parse PD-exclude
1067                         bool ok = true;
1068                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1069                                         odata + olen, stype, slen, sdata) {
1070                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1071                                         continue;
1072
1073                                 uint8_t elen = sdata[0];
1074                                 if (elen > 64)
1075                                         elen = 64;
1076
1077                                 if (elen <= 32 || elen <= entry.length) {
1078                                         ok = false;
1079                                         continue;
1080                                 }
1081
1082
1083                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1084                                 if (slen <= bytes) {
1085                                         ok = false;
1086                                         continue;
1087                                 }
1088
1089                                 uint32_t exclude = 0;
1090                                 do {
1091                                         exclude = exclude << 8 | sdata[bytes];
1092                                 } while (--bytes);
1093
1094                                 exclude >>= 8 - ((elen - entry.length) % 8);
1095                                 exclude <<= 64 - elen;
1096
1097                                 // Abusing router & priority fields for exclusion
1098                                 entry.router = entry.target;
1099                                 entry.router.s6_addr32[1] |= htonl(exclude);
1100                                 entry.priority = elen;
1101                         }
1102
1103                         if (ok) {
1104                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1105                                 parsed_ia++;
1106                         }
1107
1108                         entry.priority = 0;
1109                         memset(&entry.router, 0, sizeof(entry.router));
1110                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1111                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1112                         if (olen + 4U < sizeof(*addr))
1113                                 continue;
1114
1115                         entry.preferred = ntohl(addr->preferred);
1116                         entry.valid = ntohl(addr->valid);
1117
1118                         if (entry.preferred > entry.valid)
1119                                 continue;
1120
1121                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1122                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1123                         if (entry.t1 > entry.t2)
1124                                 entry.t1 = entry.t2;
1125
1126                         entry.length = 128;
1127                         entry.target = addr->addr;
1128
1129 #ifdef EXT_PREFIX_CLASS
1130                         uint16_t stype, slen;
1131                         uint8_t *sdata;
1132                         // Find prefix class, if any
1133                         dhcpv6_for_each_option(&addr[1], odata + olen,
1134                                         stype, slen, sdata)
1135                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1136                                         entry.class = sdata[0] << 8 | sdata[1];
1137 #endif
1138
1139                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1140                         parsed_ia++;
1141                 }
1142         }
1143         return parsed_ia;
1144 }
1145
1146
1147 static int dhcpv6_calc_refresh_timers(void)
1148 {
1149         struct odhcp6c_entry *e;
1150         size_t ia_na_entries, ia_pd_entries, i;
1151         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1152
1153         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1154         ia_na_entries /= sizeof(*e);
1155         for (i = 0; i < ia_na_entries; i++) {
1156                 if (e[i].t1 < l_t1)
1157                         l_t1 = e[i].t1;
1158
1159                 if (e[i].t2 < l_t2)
1160                         l_t2 = e[i].t2;
1161
1162                 if (e[i].valid > l_t3)
1163                         l_t3 = e[i].valid;
1164         }
1165
1166         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1167         ia_pd_entries /= sizeof(*e);
1168         for (i = 0; i < ia_pd_entries; i++) {
1169                 if (e[i].t1 < l_t1)
1170                         l_t1 = e[i].t1;
1171
1172                 if (e[i].t2 < l_t2)
1173                         l_t2 = e[i].t2;
1174
1175                 if (e[i].valid > l_t3)
1176                         l_t3 = e[i].valid;
1177         }
1178
1179         if (ia_pd_entries || ia_na_entries) {
1180                 t1 = l_t1;
1181                 t2 = l_t2;
1182                 t3 = l_t3;
1183         } else {
1184                 t1 = 600;
1185         }
1186
1187         return (int)(ia_pd_entries + ia_na_entries);
1188 }
1189
1190
1191 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1192                 const void *status_msg, const int len)
1193 {
1194         uint8_t buf[len + 3];
1195
1196         memset(buf, 0, sizeof(buf));
1197         if (len) {
1198                 buf[0] = '(';
1199                 memcpy(&buf[1], status_msg, len);
1200                 buf[len + 1] = ')';
1201         }
1202
1203         syslog(LOG_WARNING, "Server returned %s status %i %s",
1204                 scope, code, buf);
1205 }
1206
1207
1208 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1209                 const uint16_t code, const void *status_msg, const int len,
1210                 int *ret)
1211 {
1212         dhcpv6_log_status_code(code, "message", status_msg, len);
1213
1214         switch (code) {
1215         case DHCPV6_UnspecFail:
1216                 // Generic failure
1217                 *ret = 0;
1218                 break;
1219
1220         case DHCPV6_UseMulticast:
1221                 // TODO handle multicast status code
1222                 break;
1223
1224         case DHCPV6_NoAddrsAvail:
1225         case DHCPV6_NoPrefixAvail:
1226                 if (orig == DHCPV6_MSG_REQUEST)
1227                         *ret = 0; // Failure
1228                 break;
1229
1230         default:
1231                 break;
1232         }
1233 }
1234
1235
1236 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1237                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1238                 const void *status_msg, const int len,
1239                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1240 {
1241         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1242                 "IA_NA" : "IA_PD", status_msg, len);
1243
1244         switch (code) {
1245         case DHCPV6_NoBinding:
1246                 switch (orig) {
1247                 case DHCPV6_MSG_RENEW:
1248                 case DHCPV6_MSG_REBIND:
1249                         if ((*ret > 0) && !handled_status_codes[code])
1250                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1251                         break;
1252
1253                 default:
1254                         break;
1255                 }
1256                 break;
1257
1258         case DHCPV6_NoAddrsAvail:
1259         case DHCPV6_NoPrefixAvail:
1260                 switch (orig) {
1261                 case DHCPV6_MSG_REQUEST:
1262                         if (*ret != 0)
1263                                 *ret = 0;
1264                         break;
1265                 default:
1266                         break;
1267                 }
1268                 break;
1269
1270         case DHCPV6_NotOnLink:
1271                 // TODO handle not onlink in case of confirm
1272                 break;
1273
1274         default:
1275                 break;
1276         }
1277 }
1278
1279 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1280 {
1281         size_t cand_len, i;
1282         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1283
1284         // Remove identical duid server candidate
1285         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1286                 if (cand->duid_len == c[i].duid_len &&
1287                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1288                         free(c[i].ia_na);
1289                         free(c[i].ia_pd);
1290                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1291                         break;
1292                 }
1293         }
1294
1295         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1296                 i < cand_len / sizeof(*c); ++i) {
1297                 if (c[i].preference < cand->preference)
1298                         break;
1299         }
1300
1301         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1302 }
1303
1304 static void dhcpv6_clear_all_server_cand(void)
1305 {
1306         size_t cand_len, i;
1307         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1308
1309         // Server candidates need deep delete for IA_NA/IA_PD
1310         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1311                 free(c[i].ia_na);
1312                 free(c[i].ia_pd);
1313         }
1314         odhcp6c_clear_state(STATE_SERVER_CAND);
1315 }
1316
1317 int dhcpv6_promote_server_cand(void)
1318 {
1319         size_t cand_len;
1320         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1321         uint16_t hdr[2];
1322         int ret = (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) ?
1323                         DHCPV6_STATELESS : DHCPV6_STATEFUL;
1324
1325         // Clear lingering candidate state info
1326         odhcp6c_clear_state(STATE_SERVER_ID);
1327         odhcp6c_clear_state(STATE_IA_NA);
1328         odhcp6c_clear_state(STATE_IA_PD);
1329
1330         if (!cand_len)
1331                 return -1;
1332
1333         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1334                 na_mode = IA_MODE_NONE;
1335
1336                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1337                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1338
1339                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1340         }
1341
1342         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1343         hdr[1] = htons(cand->duid_len);
1344         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1345         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1346         accept_reconfig = cand->wants_reconfigure;
1347         if (cand->ia_na_len) {
1348                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1349                 free(cand->ia_na);
1350                 if (na_mode != IA_MODE_NONE)
1351                         ret = DHCPV6_STATEFUL;
1352         }
1353         if (cand->ia_pd_len) {
1354                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1355                 free(cand->ia_pd);
1356                 if (request_prefix)
1357                         ret = DHCPV6_STATEFUL;
1358         }
1359
1360         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1361         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1362
1363         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1364
1365         return ret;
1366 }