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 <arpa/inet.h>
  30 #include <netinet/in.h>
  31
  32 #include <net/if.h>
  33 #include <net/ethernet.h>
  34
  35 #include "odhcp6c.h"
  36 #include "md5.h"
  37
  38
  39 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  40                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  41 #define DHCPV6_CLIENT_PORT 546
  42 #define DHCPV6_SERVER_PORT 547
  43 #define DHCPV6_DUID_LLADDR 3
  44 #define DHCPV6_REQ_DELAY 1
  45
  46 #define DHCPV6_SOL_MAX_RT_MIN 60
  47 #define DHCPV6_SOL_MAX_RT_MAX 86400
  48 #define DHCPV6_INF_MAX_RT_MIN 60
  49 #define DHCPV6_INF_MAX_RT_MAX 86400
  50
  51 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  52                 const uint8_t transaction[3], enum dhcpv6_msg type,
  53                 const struct in6_addr *daddr);
  54
  55 static int dhcpv6_parse_ia(void *opt, void *end);
  56
  57 static int dhcpv6_calc_refresh_timers(void);
  58 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  59                 const uint16_t code, const void *status_msg, const int len,
  60                 int *ret);
  61 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  62                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  63                 const void *status_msg, const int len,
  64                 bool handled_status_codes[_DHCPV6_Status_Max],
  65                 int *ret);
  66 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  67 static void dhcpv6_clear_all_server_cand(void);
  68
  69 static reply_handler dhcpv6_handle_reply;
  70 static reply_handler dhcpv6_handle_advert;
  71 static reply_handler dhcpv6_handle_rebind_reply;
  72 static reply_handler dhcpv6_handle_reconfigure;
  73 static int dhcpv6_commit_advert(void);
  74
  75
  76
  77 // RFC 3315 - 5.5 Timeout and Delay values
  78 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  79         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  80                         dhcpv6_handle_reconfigure, NULL},
  81         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  82                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  83         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  84                         dhcpv6_handle_reply, NULL},
  85         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  86                         dhcpv6_handle_reply, NULL},
  87         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  88                         dhcpv6_handle_rebind_reply, NULL},
  89         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  90         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  91         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  92                         dhcpv6_handle_reply, NULL},
  93 };
  94
  95
  96 // Sockets
  97 static int sock = -1;
  98 static int ifindex = -1;
  99 static int64_t t1 = 0, t2 = 0, t3 = 0;
 100
 101 // IA states
 102 static int request_prefix = -1;
 103 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 104 static bool accept_reconfig = false;
 105 // Server unicast address
 106 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
 107
 108 // Reconfigure key
 109 static uint8_t reconf_key[16];
 110
 111
 112 int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
 113 {
 114         request_prefix = request_pd;
 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         uint16_t oro[] = {
 165                         htons(DHCPV6_OPT_SIP_SERVER_D),
 166                         htons(DHCPV6_OPT_SIP_SERVER_A),
 167                         htons(DHCPV6_OPT_DNS_SERVERS),
 168                         htons(DHCPV6_OPT_DNS_DOMAIN),
 169                         htons(DHCPV6_OPT_UNICAST),
 170                         htons(DHCPV6_OPT_NTP_SERVER),
 171                         htons(DHCPV6_OPT_AFTR_NAME),
 172                         htons(DHCPV6_OPT_PD_EXCLUDE),
 173                         htons(DHCPV6_OPT_SOL_MAX_RT),
 174                         htons(DHCPV6_OPT_INF_MAX_RT),
 175 #ifdef EXT_PREFIX_CLASS
 176                         htons(DHCPV6_OPT_PREFIX_CLASS),
 177 #endif
 178         };
 179         odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 180
 181         // Configure IPv6-options
 182         int val = 1;
 183         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 184         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 185         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 186         val = 0;
 187         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
 188         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 189
 190         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 191                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 192         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 193                 return -1;
 194
 195         return 0;
 196 }
 197
 198
 199 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 200 {
 201         na_mode = na;
 202         pd_mode = pd;
 203 }
 204
 205
 206 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 207 {
 208         // Build FQDN
 209         char fqdn_buf[256];
 210         gethostname(fqdn_buf, sizeof(fqdn_buf));
 211         struct {
 212                 uint16_t type;
 213                 uint16_t len;
 214                 uint8_t flags;
 215                 uint8_t data[256];
 216         } fqdn;
 217         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 218                         sizeof(fqdn.data), NULL, NULL);
 219         fqdn.type = htons(DHCPV6_OPT_FQDN);
 220         fqdn.len = htons(fqdn_len - 4);
 221         fqdn.flags = 0;
 222
 223
 224         // Build Client ID
 225         size_t cl_id_len;
 226         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 227
 228         // Get Server ID
 229         size_t srv_id_len;
 230         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 231
 232         // Build IA_PDs
 233         size_t ia_pd_entries, ia_pd_len = 0;
 234         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 235         ia_pd_entries /= sizeof(*e);
 236         struct dhcpv6_ia_hdr hdr_ia_pd = {
 237                 htons(DHCPV6_OPT_IA_PD),
 238                 htons(sizeof(hdr_ia_pd) - 4),
 239                 1, 0, 0
 240         };
 241
 242
 243         uint8_t *ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10));
 244         for (size_t i = 0; i < ia_pd_entries; ++i) {
 245                 uint8_t ex_len = 0;
 246                 if (e[i].priority > 0)
 247                         ex_len = ((e[i].priority - e[i].length - 1) / 8) + 6;
 248
 249                 struct dhcpv6_ia_prefix p = {
 250                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 251                         .len = htons(sizeof(p) - 4U + ex_len),
 252                         .prefix = e[i].length,
 253                         .addr = e[i].target
 254                 };
 255
 256                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 257                 ia_pd_len += sizeof(p);
 258
 259                 if (ex_len) {
 260                         ia_pd[ia_pd_len++] = 0;
 261                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 262                         ia_pd[ia_pd_len++] = 0;
 263                         ia_pd[ia_pd_len++] = ex_len - 4;
 264                         ia_pd[ia_pd_len++] = e[i].priority;
 265
 266                         uint32_t excl = ntohl(e[i].router.s6_addr32[1]);
 267                         excl >>= (64 - e[i].priority);
 268                         excl <<= 8 - ((e[i].priority - e[i].length) % 8);
 269
 270                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 271                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 272                         ia_pd_len += ex_len - 5;
 273                 }
 274         }
 275
 276         struct dhcpv6_ia_prefix pref = {
 277                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 278                 .len = htons(25), .prefix = request_prefix
 279         };
 280         if (request_prefix > 0 && ia_pd_len == 0 && type == DHCPV6_MSG_SOLICIT) {
 281                 ia_pd = (uint8_t*)&pref;
 282                 ia_pd_len = sizeof(pref);
 283         }
 284         hdr_ia_pd.len = htons(ntohs(hdr_ia_pd.len) + ia_pd_len);
 285
 286         // Build IA_NAs
 287         size_t ia_na_entries, ia_na_len = 0;
 288         void *ia_na = NULL;
 289         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 290         ia_na_entries /= sizeof(*e);
 291
 292         struct dhcpv6_ia_hdr hdr_ia_na = {
 293                 htons(DHCPV6_OPT_IA_NA),
 294                 htons(sizeof(hdr_ia_na) - 4),
 295                 1, 0, 0
 296         };
 297
 298         struct dhcpv6_ia_addr pa[ia_na_entries];
 299         for (size_t i = 0; i < ia_na_entries; ++i) {
 300                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 301                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 302                 pa[i].addr = e[i].target;
 303                 pa[i].preferred = 0;
 304                 pa[i].valid = 0;
 305         }
 306
 307         ia_na = pa;
 308         ia_na_len = sizeof(pa);
 309         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 310
 311         // Reconfigure Accept
 312         struct {
 313                 uint16_t type;
 314                 uint16_t length;
 315         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 316
 317         // Request Information Refresh
 318         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 319
 320         // Prepare Header
 321         size_t oro_len;
 322         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 323         struct {
 324                 uint8_t type;
 325                 uint8_t trid[3];
 326                 uint16_t elapsed_type;
 327                 uint16_t elapsed_len;
 328                 uint16_t elapsed_value;
 329                 uint16_t oro_type;
 330                 uint16_t oro_len;
 331         } hdr = {
 332                 type, {trid[0], trid[1], trid[2]},
 333                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 334                         htons((ecs > 0xffff) ? 0xffff : ecs),
 335                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 336         };
 337
 338         struct iovec iov[] = {
 339                 {&hdr, sizeof(hdr)},
 340                 {oro, oro_len},
 341                 {&oro_refresh, 0},
 342                 {cl_id, cl_id_len},
 343                 {srv_id, srv_id_len},
 344                 {&reconf_accept, sizeof(reconf_accept)},
 345                 {&fqdn, fqdn_len},
 346                 {&hdr_ia_na, sizeof(hdr_ia_na)},
 347                 {ia_na, ia_na_len},
 348                 {&hdr_ia_pd, sizeof(hdr_ia_pd)},
 349                 {ia_pd, ia_pd_len},
 350         };
 351
 352         size_t cnt = ARRAY_SIZE(iov);
 353         if (type == DHCPV6_MSG_INFO_REQ) {
 354                 cnt = 5;
 355                 iov[2].iov_len = sizeof(oro_refresh);
 356                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 357         } else if (!request_prefix) {
 358                 cnt = 9;
 359         }
 360
 361         // Disable IAs if not used
 362         if (type != DHCPV6_MSG_SOLICIT) {
 363                 iov[5].iov_len = 0;
 364                 if (ia_na_len == 0)
 365                         iov[7].iov_len = 0;
 366                 if (ia_pd_len == 0)
 367                         iov[9].iov_len = 0;
 368         }
 369
 370         if (na_mode == IA_MODE_NONE)
 371                 iov[7].iov_len = 0;
 372
 373         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 374                 0, ALL_DHCPV6_RELAYS, ifindex};
 375         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 376
 377         switch (type) {
 378         case DHCPV6_MSG_REQUEST:
 379         case DHCPV6_MSG_RENEW:
 380         case DHCPV6_MSG_RELEASE:
 381         case DHCPV6_MSG_DECLINE:
 382                 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
 383                         odhcp6c_addr_in_scope(&server_addr)) {
 384                         srv.sin6_addr = server_addr;
 385                         if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
 386                                 srv.sin6_scope_id = 0;
 387                 }
 388                 break;
 389         default:
 390                 break;
 391         }
 392
 393         if (sendmsg(sock, &msg, 0) < 0) {
 394                 char in6_str[INET6_ADDRSTRLEN];
 395
 396                 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
 397                         inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
 398                                 in6_str, sizeof(in6_str)), strerror(errno));
 399         }
 400 }
 401
 402
 403 static int64_t dhcpv6_rand_delay(int64_t time)
 404 {
 405         int random;
 406         odhcp6c_random(&random, sizeof(random));
 407         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 408 }
 409
 410
 411 int dhcpv6_request(enum dhcpv6_msg type)
 412 {
 413         uint8_t rc = 0;
 414         uint64_t timeout = UINT32_MAX;
 415         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 416
 417         if (retx->delay) {
 418                 struct timespec ts = {0, 0};
 419                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 420                 nanosleep(&ts, NULL);
 421         }
 422
 423         if (type == DHCPV6_MSG_UNKNOWN)
 424                 timeout = t1;
 425         else if (type == DHCPV6_MSG_RENEW)
 426                 timeout = (t2 > t1) ? t2 - t1 : 0;
 427         else if (type == DHCPV6_MSG_REBIND)
 428                 timeout = (t3 > t2) ? t3 - t2 : 0;
 429
 430         if (timeout == 0)
 431                 return -1;
 432
 433         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 434                         retx->name, (unsigned long long)timeout, retx->max_rc);
 435
 436         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 437
 438         // Generate transaction ID
 439         uint8_t trid[3] = {0, 0, 0};
 440         if (type != DHCPV6_MSG_UNKNOWN)
 441                 odhcp6c_random(trid, sizeof(trid));
 442         ssize_t len = -1;
 443         int64_t rto = 0;
 444
 445         do {
 446                 if (rto == 0) {
 447                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 448
 449                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 450                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 451                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 452
 453                         rto = (retx->init_timeo * 1000 + delay);
 454                 }
 455                 else
 456                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 457
 458                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 459                         rto = retx->max_timeo * 1000 +
 460                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 461
 462                 // Calculate end for this round and elapsed time
 463                 uint64_t round_end = round_start + rto;
 464                 elapsed = round_start - start;
 465
 466                 // Don't wait too long
 467                 if (round_end - start > timeout * 1000)
 468                         round_end = timeout * 1000 + start;
 469
 470                 // Built and send package
 471                 if (type != DHCPV6_MSG_UNKNOWN) {
 472                         if (type != DHCPV6_MSG_SOLICIT)
 473                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 474                                                 retx->name, (unsigned long long)elapsed, rc);
 475                         dhcpv6_send(type, trid, elapsed / 10);
 476                         rc++;
 477                 }
 478
 479                 // Receive rounds
 480                 for (; len < 0 && (round_start < round_end);
 481                                 round_start = odhcp6c_get_milli_time()) {
 482                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 483                         struct iovec iov = {buf, sizeof(buf)};
 484                         struct msghdr msg = {NULL, 0, &iov, 1,
 485                                         cmsg_buf, sizeof(cmsg_buf), 0};
 486                         struct in6_pktinfo *pktinfo = NULL;
 487
 488                         // Check for pending signal
 489                         if (odhcp6c_signal_process())
 490                                 return -1;
 491
 492                         // Set timeout for receiving
 493                         uint64_t t = round_end - round_start;
 494                         struct timeval timeout = {t / 1000, (t % 1000) * 1000};
 495                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 496                                         &timeout, sizeof(timeout));
 497
 498                         // Receive cycle
 499                         len = recvmsg(sock, &msg, 0);
 500                         if (len < 0)
 501                                 continue;
 502
 503                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 504                                 ch = CMSG_NXTHDR(&msg, ch)) {
 505                                 if (ch->cmsg_level == SOL_IPV6 &&
 506                                         ch->cmsg_type == IPV6_PKTINFO) {
 507                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 508                                         break;
 509                                 }
 510                         }
 511
 512                         if (pktinfo == NULL) {
 513                                 len = -1;
 514                                 continue;
 515                         }
 516
 517                         if (!dhcpv6_response_is_valid(buf, len, trid,
 518                                                         type, &pktinfo->ipi6_addr)) {
 519                                 len = -1;
 520                                 continue;
 521                         }
 522
 523                         uint8_t *opt = &buf[4];
 524                         uint8_t *opt_end = opt + len - 4;
 525
 526                         round_start = odhcp6c_get_milli_time();
 527                         elapsed = round_start - start;
 528                         syslog(LOG_NOTICE, "Got a valid reply after "
 529                                         "%llums", (unsigned long long)elapsed);
 530
 531                         if (retx->handler_reply)
 532                                 len = retx->handler_reply(type, rc, opt, opt_end);
 533
 534                         if (len > 0 && round_end - round_start > 1000)
 535                                 round_end = 1000 + round_start;
 536                 }
 537
 538                 // Allow
 539                 if (retx->handler_finish)
 540                         len = retx->handler_finish();
 541         } while (len < 0 && ((elapsed / 1000 < timeout) && (!retx->max_rc || rc < retx->max_rc)));
 542
 543         return len;
 544 }
 545
 546 // Message validation checks according to RFC3315 chapter 15
 547 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 548                 const uint8_t transaction[3], enum dhcpv6_msg type,
 549                 const struct in6_addr *daddr)
 550 {
 551         const struct dhcpv6_header *rep = buf;
 552         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 553                         transaction, sizeof(rep->tr_id)))
 554                 return false; // Invalid reply
 555
 556         if (type == DHCPV6_MSG_SOLICIT) {
 557                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 558                                 rep->msg_type != DHCPV6_MSG_REPLY)
 559                         return false;
 560         } else if (type == DHCPV6_MSG_UNKNOWN) {
 561                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 562                         return false;
 563         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 564                 return false;
 565         }
 566
 567         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 568                 rcmsg = DHCPV6_MSG_UNKNOWN;
 569         uint16_t otype, olen = UINT16_MAX;
 570         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 571                 ia_present = false, options_valid = true;
 572
 573         size_t client_id_len, server_id_len;
 574         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 575         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 576
 577         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 578                 if (otype == DHCPV6_OPT_CLIENTID) {
 579                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 580                                         &odata[-4], client_id, client_id_len);
 581                 } else if (otype == DHCPV6_OPT_SERVERID) {
 582                         if (server_id_len)
 583                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 584                                                 &odata[-4], server_id, server_id_len);
 585                         else
 586                                 serverid_ok = true;
 587                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 588                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 589                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 590                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 591                                 continue;
 592
 593                         md5_state_t md5;
 594                         uint8_t serverhash[16], secretbytes[16], hash[16];
 595                         memcpy(serverhash, r->key, sizeof(serverhash));
 596                         memset(r->key, 0, sizeof(r->key));
 597                         memcpy(secretbytes, reconf_key, sizeof(secretbytes));
 598
 599                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 600                                 secretbytes[i] ^= 0x36;
 601
 602                         md5_init(&md5);
 603                         md5_append(&md5, secretbytes, sizeof(secretbytes));
 604                         md5_append(&md5, buf, len);
 605                         md5_finish(&md5, hash);
 606
 607                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 608                                 secretbytes[i] ^= 0x36;
 609                                 secretbytes[i] ^= 0x5c;
 610                         }
 611
 612                         md5_init(&md5);
 613                         md5_append(&md5, secretbytes, sizeof(secretbytes));
 614                         md5_append(&md5, hash, 16);
 615                         md5_finish(&md5, hash);
 616
 617                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 618                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 619                         rcmsg = odata[0];
 620                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 621                         ia_present = true;
 622                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 623                                 options_valid = false;
 624                 }
 625                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 626                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 627                         // Options are not allowed on global level
 628                         options_valid = false;
 629                 }
 630         }
 631
 632         if (!options_valid || ((odata + olen) > end))
 633                 return false;
 634
 635         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 636                 return false;
 637
 638         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 639                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 640                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 641                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 642                         return false;
 643         }
 644
 645         return clientid_ok && serverid_ok;
 646 }
 647
 648
 649 int dhcpv6_poll_reconfigure(void)
 650 {
 651         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 652         if (ret != -1)
 653                 ret = dhcpv6_request(ret);
 654
 655         return ret;
 656 }
 657
 658
 659 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 660                 const void *opt, const void *end)
 661 {
 662         uint16_t otype, olen;
 663         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 664         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 665                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 666                                 odata[0] == DHCPV6_MSG_RENEW ||
 667                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 668                         msg = odata[0];
 669
 670         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 671         return msg;
 672 }
 673
 674
 675 // Collect all advertised servers
 676 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 677                 const void *opt, const void *end)
 678 {
 679         uint16_t olen, otype;
 680         uint8_t *odata, pref = 0;
 681         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 682                                         IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
 683                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 684         bool have_na = false;
 685         int have_pd = 0;
 686
 687         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 688                 if (orig == DHCPV6_MSG_SOLICIT &&
 689                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 690                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 691                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 692                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 693                 }
 694
 695                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 696                         memcpy(cand.duid, odata, olen);
 697                         cand.duid_len = olen;
 698                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 699                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 700
 701                         switch (error) {
 702                         case DHCPV6_NoPrefixAvail:
 703                                 // Status code on global level
 704                                 cand.preference -= 2000;
 705                                 break;
 706
 707                         default :
 708                                 break;
 709                         }
 710                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 711                                 cand.preference >= 0) {
 712                         cand.preference = pref = odata[0];
 713                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
 714                         cand.server_addr = *(struct in6_addr *)odata;
 715                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 716                         cand.wants_reconfigure = true;
 717                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 718                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 719                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 720                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 721                                 cand.sol_max_rt = sol_max_rt;
 722                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 723                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 724                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 725                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 726                                 cand.inf_max_rt = inf_max_rt;
 727                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 728                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 729                         uint8_t *oend = odata + olen, *d;
 730                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 731                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 732                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 733                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 734                                         have_pd = p->prefix;
 735                                 }
 736                         }
 737                 } else if (otype == DHCPV6_OPT_IA_NA) {
 738                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 739                         uint8_t *oend = odata + olen, *d;
 740                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 741                                 if (otype == DHCPV6_OPT_IA_ADDR)
 742                                         have_na = true;
 743                 }
 744         }
 745
 746         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 747                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 748                 /*
 749                  * RFC7083 states to process the SOL_MAX_RT and
 750                  * INF_MAX_RT options even if the DHCPv6 server
 751                  * did not propose any IA_NA and/or IA_PD
 752                  */
 753                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 754                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 755                 return -1;
 756         }
 757
 758         if (na_mode != IA_MODE_NONE && !have_na) {
 759                 cand.has_noaddravail = true;
 760                 cand.preference -= 1000;
 761         }
 762
 763         if (pd_mode != IA_MODE_NONE) {
 764                 if (have_pd)
 765                         cand.preference += 2000 + (128 - have_pd);
 766                 else
 767                         cand.preference -= 2000;
 768         }
 769
 770         if (cand.duid_len > 0) {
 771                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 772                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 773                 dhcpv6_add_server_cand(&cand);
 774         }
 775
 776         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 777 }
 778
 779
 780 static int dhcpv6_commit_advert(void)
 781 {
 782         return dhcpv6_promote_server_cand();
 783 }
 784
 785
 786 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 787                 const void *opt, const void *end)
 788 {
 789         dhcpv6_handle_advert(orig, rc, opt, end);
 790         if (dhcpv6_commit_advert() < 0)
 791                 return -1;
 792
 793         return dhcpv6_handle_reply(orig, rc, opt, end);
 794 }
 795
 796
 797 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 798                 const void *opt, const void *end)
 799 {
 800         uint8_t *odata;
 801         uint16_t otype, olen;
 802         uint32_t refresh = UINT32_MAX;
 803         int ret = 1;
 804         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 805
 806         odhcp6c_expire();
 807
 808         if (orig == DHCPV6_MSG_UNKNOWN) {
 809                 static time_t last_update = 0;
 810                 time_t now = odhcp6c_get_milli_time() / 1000;
 811
 812                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 813                 last_update = now;
 814
 815                 t1 -= elapsed;
 816                 t2 -= elapsed;
 817                 t3 -= elapsed;
 818
 819                 if (t1 < 0)
 820                         t1 = 0;
 821
 822                 if (t2 < 0)
 823                         t2 = 0;
 824
 825                 if (t3 < 0)
 826                         t3 = 0;
 827         }
 828
 829         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 830                 // Delete NA and PD we have in the state from the Advert
 831                 odhcp6c_clear_state(STATE_IA_NA);
 832                 odhcp6c_clear_state(STATE_IA_PD);
 833         }
 834
 835         if (opt) {
 836                 odhcp6c_clear_state(STATE_DNS);
 837                 odhcp6c_clear_state(STATE_SEARCH);
 838                 odhcp6c_clear_state(STATE_SNTP_IP);
 839                 odhcp6c_clear_state(STATE_SNTP_FQDN);
 840                 odhcp6c_clear_state(STATE_SIP_IP);
 841                 odhcp6c_clear_state(STATE_SIP_FQDN);
 842                 odhcp6c_clear_state(STATE_AFTR_NAME);
 843         }
 844
 845         // Parse and find all matching IAs
 846         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 847                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 848                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 849                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 850
 851                         // Test ID
 852                         if (ia_hdr->iaid != 1)
 853                                 continue;
 854
 855                         uint16_t code = DHCPV6_Success;
 856                         uint16_t stype, slen;
 857                         uint8_t *sdata;
 858                         // Get and handle status code
 859                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 860                                         stype, slen, sdata) {
 861                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 862                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 863                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 864
 865                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 866
 867                                         if (code == DHCPV6_Success)
 868                                                 continue;
 869
 870                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 871                                                 code, mdata, mlen, handled_status_codes, &ret);
 872
 873
 874                                         if (ret > 0)
 875                                                 return ret;
 876                                         break;
 877                                 }
 878                         }
 879
 880                         if (code != DHCPV6_Success)
 881                                 continue;
 882
 883                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 884                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
 885                         server_addr = *(struct in6_addr *)odata;
 886                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 887                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 888                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 889                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 890
 891                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 892                 }
 893                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 894                         if (olen % 16 == 0)
 895                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 896                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 897                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 898                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 899                         uint16_t stype, slen;
 900                         uint8_t *sdata;
 901                         // Test status and bail if error
 902                         dhcpv6_for_each_option(odata, odata + olen,
 903                                         stype, slen, sdata) {
 904                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 905                                                 stype == NTP_SRV_ADDR))
 906                                         odhcp6c_add_state(STATE_SNTP_IP,
 907                                                         sdata, slen);
 908                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 909                                         odhcp6c_add_state(STATE_SNTP_FQDN,
 910                                                         sdata, slen);
 911                         }
 912                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 913                         if (olen == 16)
 914                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 915                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 916                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 917                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 918                         refresh = ntohl(*((uint32_t*)odata));
 919                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 920                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 921                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 922                         if (r->protocol == 3 && r->algorithm == 1 &&
 923                                         r->reconf_type == 1)
 924                                 memcpy(reconf_key, r->key, sizeof(r->key));
 925                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
 926                         size_t cur_len;
 927                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
 928                         if (cur_len == 0)
 929                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
 930                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 931                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 932                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 933                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 934                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
 935                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 936                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 937                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 938                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 939                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
 940                 }else if (otype != DHCPV6_OPT_CLIENTID &&
 941                                 otype != DHCPV6_OPT_SERVERID) {
 942                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
 943                                         &odata[-4], olen + 4);
 944                 }
 945         }
 946
 947         if (orig != DHCPV6_MSG_INFO_REQ) {
 948                 // Update refresh timers if no fatal status code was received
 949                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
 950                         switch (orig) {
 951                         case DHCPV6_MSG_RENEW:
 952                                 // Send further renews if T1 is not set
 953                                 if (!t1)
 954                                         ret = -1;
 955                                 break;
 956                         case DHCPV6_MSG_REBIND:
 957                                 // Send further rebinds if T1 and T2 is not set
 958                                 if (!t1 && !t2)
 959                                         ret = -1;
 960                                 break;
 961
 962                         case DHCPV6_MSG_REQUEST:
 963                                 // All server candidates can be cleared if not yet bound
 964                                 if (!odhcp6c_is_bound())
 965                                         dhcpv6_clear_all_server_cand();
 966
 967                         default :
 968                                 break;
 969                         }
 970                 }
 971         }
 972         else if (ret > 0) {
 973                 // All server candidates can be cleared if not yet bound
 974                 if (!odhcp6c_is_bound())
 975                         dhcpv6_clear_all_server_cand();
 976
 977                 t1 = refresh;
 978         }
 979
 980         return ret;
 981 }
 982
 983
 984 static int dhcpv6_parse_ia(void *opt, void *end)
 985 {
 986         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
 987         int parsed_ia = 0;
 988         uint32_t t1, t2;
 989         uint16_t otype, olen;
 990         uint8_t *odata;
 991
 992         t1 = ntohl(ia_hdr->t1);
 993         t2 = ntohl(ia_hdr->t2);
 994
 995         if (t1 > t2)
 996                 return 0;
 997
 998         // Update address IA
 999         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1000                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1001                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1002
1003                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1004                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1005                         if (olen + 4U < sizeof(*prefix))
1006                                 continue;
1007
1008                         entry.valid = ntohl(prefix->valid);
1009                         entry.preferred = ntohl(prefix->preferred);
1010
1011                         if (entry.preferred > entry.valid)
1012                                 continue;
1013
1014                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1015                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1016                         if (entry.t1 > entry.t2)
1017                                 entry.t1 = entry.t2;
1018
1019                         entry.length = prefix->prefix;
1020                         entry.target = prefix->addr;
1021                         uint16_t stype, slen;
1022                         uint8_t *sdata;
1023
1024 #ifdef EXT_PREFIX_CLASS
1025                         // Find prefix class, if any
1026                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1027                                         stype, slen, sdata)
1028                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1029                                         entry.class = sdata[0] << 8 | sdata[1];
1030 #endif
1031
1032                         // Parse PD-exclude
1033                         bool ok = true;
1034                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1035                                         odata + olen, stype, slen, sdata) {
1036                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1037                                         continue;
1038
1039                                 uint8_t elen = sdata[0];
1040                                 if (elen > 64)
1041                                         elen = 64;
1042
1043                                 if (elen <= 32 || elen <= entry.length) {
1044                                         ok = false;
1045                                         continue;
1046                                 }
1047
1048
1049                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1050                                 if (slen <= bytes) {
1051                                         ok = false;
1052                                         continue;
1053                                 }
1054
1055                                 uint32_t exclude = 0;
1056                                 do {
1057                                         exclude = exclude << 8 | sdata[bytes];
1058                                 } while (--bytes);
1059
1060                                 exclude >>= 8 - ((elen - entry.length) % 8);
1061                                 exclude <<= 64 - elen;
1062
1063                                 // Abusing router & priority fields for exclusion
1064                                 entry.router = entry.target;
1065                                 entry.router.s6_addr32[1] |= htonl(exclude);
1066                                 entry.priority = elen;
1067                         }
1068
1069                         if (ok) {
1070                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1071                                 parsed_ia++;
1072                         }
1073
1074                         entry.priority = 0;
1075                         memset(&entry.router, 0, sizeof(entry.router));
1076                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1077                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1078                         if (olen + 4U < sizeof(*addr))
1079                                 continue;
1080
1081                         entry.preferred = ntohl(addr->preferred);
1082                         entry.valid = ntohl(addr->valid);
1083
1084                         if (entry.preferred > entry.valid)
1085                                 continue;
1086
1087                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1088                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1089                         if (entry.t1 > entry.t2)
1090                                 entry.t1 = entry.t2;
1091
1092                         entry.length = 128;
1093                         entry.target = addr->addr;
1094
1095 #ifdef EXT_PREFIX_CLASS
1096                         uint16_t stype, slen;
1097                         uint8_t *sdata;
1098                         // Find prefix class, if any
1099                         dhcpv6_for_each_option(&addr[1], odata + olen,
1100                                         stype, slen, sdata)
1101                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1102                                         entry.class = sdata[0] << 8 | sdata[1];
1103 #endif
1104
1105                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1106                         parsed_ia++;
1107                 }
1108         }
1109         return parsed_ia;
1110 }
1111
1112
1113 static int dhcpv6_calc_refresh_timers(void)
1114 {
1115         struct odhcp6c_entry *e;
1116         size_t ia_na_entries, ia_pd_entries, i;
1117         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1118
1119         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1120         ia_na_entries /= sizeof(*e);
1121         for (i = 0; i < ia_na_entries; i++) {
1122                 if (e[i].t1 < l_t1)
1123                         l_t1 = e[i].t1;
1124
1125                 if (e[i].t2 < l_t2)
1126                         l_t2 = e[i].t2;
1127
1128                 if (e[i].valid > l_t3)
1129                         l_t3 = e[i].valid;
1130         }
1131
1132         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1133         ia_pd_entries /= sizeof(*e);
1134         for (i = 0; i < ia_pd_entries; i++) {
1135                 if (e[i].t1 < l_t1)
1136                         l_t1 = e[i].t1;
1137
1138                 if (e[i].t2 < l_t2)
1139                         l_t2 = e[i].t2;
1140
1141                 if (e[i].valid > l_t3)
1142                         l_t3 = e[i].valid;
1143         }
1144
1145         if (ia_pd_entries || ia_na_entries) {
1146                 t1 = l_t1;
1147                 t2 = l_t2;
1148                 t3 = l_t3;
1149         }
1150
1151         return (int)(ia_pd_entries + ia_na_entries);
1152 }
1153
1154
1155 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1156                 const void *status_msg, const int len)
1157 {
1158         uint8_t buf[len + 3];
1159
1160         memset(buf, 0, sizeof(buf));
1161         if (len) {
1162                 buf[0] = '(';
1163                 memcpy(&buf[1], status_msg, len);
1164                 buf[len + 1] = ')';
1165         }
1166
1167         syslog(LOG_WARNING, "Server returned %s status %i %s",
1168                 scope, code, buf);
1169 }
1170
1171
1172 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1173                 const uint16_t code, const void *status_msg, const int len,
1174                 int *ret)
1175 {
1176         dhcpv6_log_status_code(code, "message", status_msg, len);
1177
1178         switch (code) {
1179         case DHCPV6_UnspecFail:
1180                 // Generic failure
1181                 *ret = 0;
1182                 break;
1183
1184         case DHCPV6_UseMulticast:
1185                 switch(orig) {
1186                 case DHCPV6_MSG_REQUEST:
1187                 case DHCPV6_MSG_RENEW:
1188                 case DHCPV6_MSG_RELEASE:
1189                 case DHCPV6_MSG_DECLINE:
1190                         // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1191                         server_addr = in6addr_any;
1192                         *ret = 0;
1193                         break;
1194                 default:
1195                         break;
1196                 }
1197                 break;
1198
1199         case DHCPV6_NoAddrsAvail:
1200         case DHCPV6_NoPrefixAvail:
1201                 if (orig == DHCPV6_MSG_REQUEST)
1202                         *ret = 0; // Failure
1203                 break;
1204
1205         default:
1206                 break;
1207         }
1208 }
1209
1210
1211 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1212                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1213                 const void *status_msg, const int len,
1214                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1215 {
1216         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1217                 "IA_NA" : "IA_PD", status_msg, len);
1218
1219         switch (code) {
1220         case DHCPV6_NoBinding:
1221                 switch (orig) {
1222                 case DHCPV6_MSG_RENEW:
1223                 case DHCPV6_MSG_REBIND:
1224                         if ((*ret > 0) && !handled_status_codes[code])
1225                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1226                         break;
1227
1228                 default:
1229                         break;
1230                 }
1231                 break;
1232
1233         case DHCPV6_NoAddrsAvail:
1234         case DHCPV6_NoPrefixAvail:
1235                 switch (orig) {
1236                 case DHCPV6_MSG_REQUEST:
1237                         if (*ret != 0)
1238                                 *ret = 0;
1239                         break;
1240                 default:
1241                         break;
1242                 }
1243                 break;
1244
1245         case DHCPV6_NotOnLink:
1246                 // TODO handle not onlink in case of confirm
1247                 break;
1248
1249         default:
1250                 break;
1251         }
1252 }
1253
1254 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1255 {
1256         size_t cand_len, i;
1257         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1258
1259         // Remove identical duid server candidate
1260         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1261                 if (cand->duid_len == c[i].duid_len &&
1262                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1263                         free(c[i].ia_na);
1264                         free(c[i].ia_pd);
1265                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1266                         break;
1267                 }
1268         }
1269
1270         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1271                 i < cand_len / sizeof(*c); ++i) {
1272                 if (c[i].preference < cand->preference)
1273                         break;
1274         }
1275
1276         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1277 }
1278
1279 static void dhcpv6_clear_all_server_cand(void)
1280 {
1281         size_t cand_len, i;
1282         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1283
1284         // Server candidates need deep delete for IA_NA/IA_PD
1285         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1286                 free(c[i].ia_na);
1287                 free(c[i].ia_pd);
1288         }
1289         odhcp6c_clear_state(STATE_SERVER_CAND);
1290 }
1291
1292 int dhcpv6_promote_server_cand(void)
1293 {
1294         size_t cand_len;
1295         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1296         uint16_t hdr[2];
1297         int ret = DHCPV6_STATELESS;
1298
1299         // Clear lingering candidate state info
1300         odhcp6c_clear_state(STATE_SERVER_ID);
1301         odhcp6c_clear_state(STATE_IA_NA);
1302         odhcp6c_clear_state(STATE_IA_PD);
1303
1304         if (!cand_len)
1305                 return -1;
1306
1307         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1308                 na_mode = IA_MODE_NONE;
1309
1310                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1311                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1312
1313                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1314         }
1315
1316         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1317         hdr[1] = htons(cand->duid_len);
1318         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1319         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1320         accept_reconfig = cand->wants_reconfigure;
1321         if (cand->ia_na_len) {
1322                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1323                 free(cand->ia_na);
1324                 if (na_mode != IA_MODE_NONE)
1325                         ret = DHCPV6_STATEFUL;
1326         }
1327         if (cand->ia_pd_len) {
1328                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1329                 free(cand->ia_pd);
1330                 if (request_prefix)
1331                         ret = DHCPV6_STATEFUL;
1332         }
1333
1334         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1335         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1336
1337         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1338
1339         return ret;
1340 }