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