src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <stdlib.h>
  19 #include <signal.h>
  20 #include <limits.h>
  21 #include <resolv.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <syslog.h>
  25 #include <stdbool.h>
  26 #include <sys/time.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/socket.h>
  29 #include <netinet/in.h>
  30
  31 #include <net/if.h>
  32 #include <net/ethernet.h>
  33
  34 #include "odhcp6c.h"
  35 #include "md5.h"
  36
  37
  38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  39                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  40 #define DHCPV6_CLIENT_PORT 546
  41 #define DHCPV6_SERVER_PORT 547
  42 #define DHCPV6_DUID_LLADDR 3
  43 #define DHCPV6_REQ_DELAY 1
  44
  45 #define DHCPV6_SOL_MAX_RT_MIN 60
  46 #define DHCPV6_SOL_MAX_RT_MAX 86400
  47 #define DHCPV6_INF_MAX_RT_MIN 60
  48 #define DHCPV6_INF_MAX_RT_MAX 86400
  49
  50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  51                 const uint8_t transaction[3], enum dhcpv6_msg type,
  52                 const struct in6_addr *daddr);
  53
  54 static int dhcpv6_parse_ia(void *opt, void *end);
  55
  56 static int dhcpv6_calc_refresh_timers(void);
  57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  58                 const uint16_t code, const void *status_msg, const int len,
  59                 int *ret);
  60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  61                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  62                 const void *status_msg, const int len,
  63                 bool handled_status_codes[_DHCPV6_Status_Max],
  64                 int *ret);
  65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  66 static void dhcpv6_clear_all_server_cand(void);
  67
  68 static reply_handler dhcpv6_handle_reply;
  69 static reply_handler dhcpv6_handle_advert;
  70 static reply_handler dhcpv6_handle_rebind_reply;
  71 static reply_handler dhcpv6_handle_reconfigure;
  72 static int dhcpv6_commit_advert(void);
  73
  74
  75
  76 // RFC 3315 - 5.5 Timeout and Delay values
  77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  78         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  79                         dhcpv6_handle_reconfigure, NULL},
  80         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  81                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  82         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  83                         dhcpv6_handle_reply, NULL},
  84         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  85                         dhcpv6_handle_reply, NULL},
  86         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  87                         dhcpv6_handle_rebind_reply, NULL},
  88         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  89         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  90         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  91                         dhcpv6_handle_reply, NULL},
  92 };
  93
  94
  95 // Sockets
  96 static int sock = -1;
  97 static int ifindex = -1;
  98 static int64_t t1 = 0, t2 = 0, t3 = 0;
  99
 100 // IA states
 101 static int request_prefix = -1;
 102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 103 static bool accept_reconfig = false;
 104
 105 // Reconfigure key
 106 static uint8_t reconf_key[16];
 107
 108 // client options
 109 static unsigned int client_options = 0;
 110
 111
 112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 113 {
 114         client_options = options;
 115         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 116
 117         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 118         if (sock < 0)
 119                 return -1;
 120
 121         // Detect interface
 122         struct ifreq ifr;
 123         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 124         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 125                 return -1;
 126         ifindex = ifr.ifr_ifindex;
 127
 128         // Create client DUID
 129         size_t client_id_len;
 130         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 131         if (client_id_len == 0) {
 132                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 133                                 DHCPV6_DUID_LLADDR, 0, 1};
 134
 135                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 136                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 137
 138                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 139                 struct ifreq ifs[100], *ifp, *ifend;
 140                 struct ifconf ifc;
 141                 ifc.ifc_req = ifs;
 142                 ifc.ifc_len = sizeof(ifs);
 143
 144                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 145                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 146                         // If our interface doesn't have an address...
 147                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 148                         for (ifp = ifc.ifc_req; ifp < ifend &&
 149                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 150                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 151                                                 sizeof(ifr.ifr_name));
 152                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 153                                         continue;
 154
 155                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 156                                                 ETHER_ADDR_LEN);
 157                         }
 158                 }
 159
 160                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 161         }
 162
 163         // Create ORO
 164         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 165                 uint16_t oro[] = {
 166                         htons(DHCPV6_OPT_SIP_SERVER_D),
 167                         htons(DHCPV6_OPT_SIP_SERVER_A),
 168                         htons(DHCPV6_OPT_DNS_SERVERS),
 169                         htons(DHCPV6_OPT_DNS_DOMAIN),
 170                         htons(DHCPV6_OPT_SNTP_SERVERS),
 171                         htons(DHCPV6_OPT_NTP_SERVER),
 172                         htons(DHCPV6_OPT_AFTR_NAME),
 173                         htons(DHCPV6_OPT_PD_EXCLUDE),
 174                         htons(DHCPV6_OPT_SOL_MAX_RT),
 175                         htons(DHCPV6_OPT_INF_MAX_RT),
 176 #ifdef EXT_PREFIX_CLASS
 177                         htons(DHCPV6_OPT_PREFIX_CLASS),
 178 #endif
 179 #ifdef EXT_CER_ID
 180                         htons(DHCPV6_OPT_CER_ID),
 181 #endif
 182                 };
 183                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 184         }
 185
 186         // Configure IPv6-options
 187         int val = 1;
 188         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 189         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 190         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 191         val = 0;
 192         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 193
 194         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 195                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 196         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 197                 return -1;
 198
 199         return 0;
 200 }
 201
 202 enum {
 203         IOV_HDR=0,
 204         IOV_ORO,
 205         IOV_ORO_REFRESH,
 206         IOV_CL_ID,
 207         IOV_SRV_ID,
 208         IOV_VENDOR_CLASS_HDR,
 209         IOV_VENDOR_CLASS,
 210         IOV_USER_CLASS_HDR,
 211         IOV_USER_CLASS,
 212         IOV_RECONF_ACCEPT,
 213         IOV_FQDN,
 214         IOV_HDR_IA_NA,
 215         IOV_IA_NA,
 216         IOV_IA_PD,
 217         IOV_TOTAL
 218 };
 219
 220 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 221 {
 222         na_mode = na;
 223         pd_mode = pd;
 224 }
 225
 226 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 227 {
 228         // Build FQDN
 229         char fqdn_buf[256];
 230         gethostname(fqdn_buf, sizeof(fqdn_buf));
 231         struct {
 232                 uint16_t type;
 233                 uint16_t len;
 234                 uint8_t flags;
 235                 uint8_t data[256];
 236         } fqdn;
 237         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 238                         sizeof(fqdn.data), NULL, NULL);
 239         fqdn.type = htons(DHCPV6_OPT_FQDN);
 240         fqdn.len = htons(fqdn_len - 4);
 241         fqdn.flags = 0;
 242
 243
 244         // Build Client ID
 245         size_t cl_id_len;
 246         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 247
 248         // Get Server ID
 249         size_t srv_id_len;
 250         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 251
 252         // Build IA_PDs
 253         size_t ia_pd_entries = 0, ia_pd_len = 0;
 254         uint8_t *ia_pd;
 255
 256         if (type == DHCPV6_MSG_SOLICIT) {
 257                 odhcp6c_clear_state(STATE_IA_PD);
 258                 size_t n_prefixes;
 259                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 260                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 261
 262                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 263
 264                 for (size_t i = 0; i < n_prefixes; i++) {
 265                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 266                                 htons(DHCPV6_OPT_IA_PD),
 267                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 268                                 request_prefixes[i].iaid, 0, 0
 269                         };
 270                         struct dhcpv6_ia_prefix pref = {
 271                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 272                                 .len = htons(25), .prefix = request_prefixes[i].length
 273                         };
 274                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 275                         ia_pd_len += sizeof(hdr_ia_pd);
 276                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 277                         ia_pd_len += sizeof(pref);
 278                 }
 279         } else {
 280                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 281                 ia_pd_entries /= sizeof(*e);
 282
 283                 // we're too lazy to count our distinct IAIDs,
 284                 // so just allocate maximally needed space
 285                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 286                                         sizeof(struct dhcpv6_ia_hdr)));
 287
 288                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 289                         uint32_t iaid = e[i].iaid;
 290
 291                         // check if this is an unprocessed IAID and skip if not.
 292                         int new_iaid = 1;
 293                         for (int j = i-1; j >= 0; j--) {
 294                                 if (e[j].iaid == iaid) {
 295                                         new_iaid = 0;
 296                                         break;
 297                                 }
 298                         }
 299
 300                         if (!new_iaid)
 301                                 continue;
 302
 303                         // construct header
 304                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 305                                 htons(DHCPV6_OPT_IA_PD),
 306                                 htons(sizeof(hdr_ia_pd) - 4),
 307                                 iaid, 0, 0
 308                         };
 309
 310                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 311                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 312                         ia_pd_len += sizeof(hdr_ia_pd);
 313
 314                         for (size_t j = i; j < ia_pd_entries; j++) {
 315                                 if (e[j].iaid != iaid)
 316                                         continue;
 317
 318                                 uint8_t ex_len = 0;
 319                                 if (e[j].priority > 0)
 320                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 321
 322                                 struct dhcpv6_ia_prefix p = {
 323                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 324                                         .len = htons(sizeof(p) - 4U + ex_len),
 325                                         .prefix = e[j].length,
 326                                         .addr = e[j].target
 327                                 };
 328
 329                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 330                                 ia_pd_len += sizeof(p);
 331
 332                                 if (ex_len) {
 333                                         ia_pd[ia_pd_len++] = 0;
 334                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 335                                         ia_pd[ia_pd_len++] = 0;
 336                                         ia_pd[ia_pd_len++] = ex_len - 4;
 337                                         ia_pd[ia_pd_len++] = e[j].priority;
 338
 339                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 340                                         excl >>= (64 - e[j].priority);
 341                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 342
 343                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 344                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 345                                         ia_pd_len += ex_len - 5;
 346                                 }
 347
 348                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 349                         }
 350                 }
 351         }
 352
 353         if (ia_pd_entries > 0)
 354                 request_prefix = 1;
 355
 356         // Build IA_NAs
 357         size_t ia_na_entries, ia_na_len = 0;
 358         void *ia_na = NULL;
 359         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 360         ia_na_entries /= sizeof(*e);
 361
 362         struct dhcpv6_ia_hdr hdr_ia_na = {
 363                 htons(DHCPV6_OPT_IA_NA),
 364                 htons(sizeof(hdr_ia_na) - 4),
 365                 1, 0, 0
 366         };
 367
 368         struct dhcpv6_ia_addr pa[ia_na_entries];
 369         for (size_t i = 0; i < ia_na_entries; ++i) {
 370                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 371                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 372                 pa[i].addr = e[i].target;
 373                 pa[i].preferred = 0;
 374                 pa[i].valid = 0;
 375         }
 376
 377         ia_na = pa;
 378         ia_na_len = sizeof(pa);
 379         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 380
 381         // Reconfigure Accept
 382         struct {
 383                 uint16_t type;
 384                 uint16_t length;
 385         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 386
 387         // Request Information Refresh
 388         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 389
 390         // Build vendor-class option
 391         size_t vendor_class_len, user_class_len;
 392         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 393         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 394
 395         struct {
 396                 uint16_t type;
 397                 uint16_t length;
 398         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 399
 400         struct {
 401                 uint16_t type;
 402                 uint16_t length;
 403         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 404
 405         // Prepare Header
 406         size_t oro_len;
 407         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 408         struct {
 409                 uint8_t type;
 410                 uint8_t trid[3];
 411                 uint16_t elapsed_type;
 412                 uint16_t elapsed_len;
 413                 uint16_t elapsed_value;
 414                 uint16_t oro_type;
 415                 uint16_t oro_len;
 416         } hdr = {
 417                 type, {trid[0], trid[1], trid[2]},
 418                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 419                         htons((ecs > 0xffff) ? 0xffff : ecs),
 420                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 421         };
 422
 423         struct iovec iov[IOV_TOTAL] = {
 424                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 425                 [IOV_ORO] = {oro, oro_len},
 426                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 427                 [IOV_CL_ID] = {cl_id, cl_id_len},
 428                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 429                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 430                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 431                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 432                 [IOV_USER_CLASS] = {user_class, user_class_len},
 433                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 434                 [IOV_FQDN] = {&fqdn, fqdn_len},
 435                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 436                 [IOV_IA_NA] = {ia_na, ia_na_len},
 437                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 438         };
 439
 440         size_t cnt = IOV_TOTAL;
 441         if (type == DHCPV6_MSG_INFO_REQ) {
 442                 cnt = 9;
 443                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 444                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 445         } else if (!request_prefix) {
 446                 cnt = 13;
 447         }
 448
 449         // Disable IAs if not used
 450         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 451                 iov[IOV_HDR_IA_NA].iov_len = 0;
 452
 453         if (na_mode == IA_MODE_NONE)
 454                 iov[IOV_HDR_IA_NA].iov_len = 0;
 455
 456         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 457                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 458                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 459
 460         if (!(client_options & DHCPV6_CLIENT_FQDN))
 461                 iov[IOV_FQDN].iov_len = 0;
 462
 463         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 464                 0, ALL_DHCPV6_RELAYS, ifindex};
 465         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 466
 467         sendmsg(sock, &msg, 0);
 468 }
 469
 470
 471 static int64_t dhcpv6_rand_delay(int64_t time)
 472 {
 473         int random;
 474         odhcp6c_random(&random, sizeof(random));
 475         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 476 }
 477
 478
 479 int dhcpv6_request(enum dhcpv6_msg type)
 480 {
 481         uint8_t rc = 0;
 482         uint64_t timeout = UINT32_MAX;
 483         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 484
 485         if (retx->delay) {
 486                 struct timespec ts = {0, 0};
 487                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 488                 nanosleep(&ts, NULL);
 489         }
 490
 491         if (type == DHCPV6_MSG_UNKNOWN)
 492                 timeout = t1;
 493         else if (type == DHCPV6_MSG_RENEW)
 494                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 495         else if (type == DHCPV6_MSG_REBIND)
 496                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 497
 498         if (timeout == 0)
 499                 return -1;
 500
 501         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 502                         retx->name, (unsigned long long)timeout, retx->max_rc);
 503
 504         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 505
 506         // Generate transaction ID
 507         uint8_t trid[3] = {0, 0, 0};
 508         if (type != DHCPV6_MSG_UNKNOWN)
 509                 odhcp6c_random(trid, sizeof(trid));
 510         ssize_t len = -1;
 511         int64_t rto = 0;
 512
 513         do {
 514                 if (rto == 0) {
 515                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 516
 517                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 518                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 519                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 520
 521                         rto = (retx->init_timeo * 1000 + delay);
 522                 }
 523                 else
 524                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 525
 526                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 527                         rto = retx->max_timeo * 1000 +
 528                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 529
 530                 // Calculate end for this round and elapsed time
 531                 uint64_t round_end = round_start + rto;
 532                 elapsed = round_start - start;
 533
 534                 // Don't wait too long if timeout differs from infinite
 535                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 536                         round_end = timeout * 1000 + start;
 537
 538                 // Built and send package
 539                 if (type != DHCPV6_MSG_UNKNOWN) {
 540                         if (type != DHCPV6_MSG_SOLICIT)
 541                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 542                                                 retx->name, (unsigned long long)elapsed, rc);
 543                         dhcpv6_send(type, trid, elapsed / 10);
 544                         rc++;
 545                 }
 546
 547                 // Receive rounds
 548                 for (; len < 0 && (round_start < round_end);
 549                                 round_start = odhcp6c_get_milli_time()) {
 550                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 551                         struct iovec iov = {buf, sizeof(buf)};
 552                         struct msghdr msg = {NULL, 0, &iov, 1,
 553                                         cmsg_buf, sizeof(cmsg_buf), 0};
 554                         struct in6_pktinfo *pktinfo = NULL;
 555
 556                         // Check for pending signal
 557                         if (odhcp6c_signal_process())
 558                                 return -1;
 559
 560                         // Set timeout for receiving
 561                         uint64_t t = round_end - round_start;
 562                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 563                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 564                                         &tv, sizeof(tv));
 565
 566                         // Receive cycle
 567                         len = recvmsg(sock, &msg, 0);
 568                         if (len < 0)
 569                                 continue;
 570
 571                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 572                                 ch = CMSG_NXTHDR(&msg, ch)) {
 573                                 if (ch->cmsg_level == SOL_IPV6 &&
 574                                         ch->cmsg_type == IPV6_PKTINFO) {
 575                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 576                                         break;
 577                                 }
 578                         }
 579
 580                         if (pktinfo == NULL) {
 581                                 len = -1;
 582                                 continue;
 583                         }
 584
 585                         if (!dhcpv6_response_is_valid(buf, len, trid,
 586                                                         type, &pktinfo->ipi6_addr)) {
 587                                 len = -1;
 588                                 continue;
 589                         }
 590
 591                         uint8_t *opt = &buf[4];
 592                         uint8_t *opt_end = opt + len - 4;
 593
 594                         round_start = odhcp6c_get_milli_time();
 595                         elapsed = round_start - start;
 596                         syslog(LOG_NOTICE, "Got a valid reply after "
 597                                         "%llums", (unsigned long long)elapsed);
 598
 599                         if (retx->handler_reply)
 600                                 len = retx->handler_reply(type, rc, opt, opt_end);
 601
 602                         if (len > 0 && round_end - round_start > 1000)
 603                                 round_end = 1000 + round_start;
 604                 }
 605
 606                 // Allow
 607                 if (retx->handler_finish)
 608                         len = retx->handler_finish();
 609         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 610                         (!retx->max_rc || rc < retx->max_rc));
 611         return len;
 612 }
 613
 614 // Message validation checks according to RFC3315 chapter 15
 615 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 616                 const uint8_t transaction[3], enum dhcpv6_msg type,
 617                 const struct in6_addr *daddr)
 618 {
 619         const struct dhcpv6_header *rep = buf;
 620         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 621                         transaction, sizeof(rep->tr_id)))
 622                 return false; // Invalid reply
 623
 624         if (type == DHCPV6_MSG_SOLICIT) {
 625                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 626                                 rep->msg_type != DHCPV6_MSG_REPLY)
 627                         return false;
 628         } else if (type == DHCPV6_MSG_UNKNOWN) {
 629                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 630                         return false;
 631         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 632                 return false;
 633         }
 634
 635         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 636                 rcmsg = DHCPV6_MSG_UNKNOWN;
 637         uint16_t otype, olen = UINT16_MAX;
 638         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 639                 ia_present = false, options_valid = true;
 640
 641         size_t client_id_len, server_id_len;
 642         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 643         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 644
 645         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 646                 if (otype == DHCPV6_OPT_CLIENTID) {
 647                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 648                                         &odata[-4], client_id, client_id_len);
 649                 } else if (otype == DHCPV6_OPT_SERVERID) {
 650                         if (server_id_len)
 651                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 652                                                 &odata[-4], server_id, server_id_len);
 653                         else
 654                                 serverid_ok = true;
 655                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 656                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 657                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 658                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 659                                 continue;
 660
 661                         md5_ctx_t md5;
 662                         uint8_t serverhash[16], secretbytes[64], hash[16];
 663                         memcpy(serverhash, r->key, sizeof(serverhash));
 664                         memset(r->key, 0, sizeof(r->key));
 665
 666                         memset(secretbytes, 0, sizeof(secretbytes));
 667                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 668
 669                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 670                                 secretbytes[i] ^= 0x36;
 671
 672                         md5_begin(&md5);
 673                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 674                         md5_hash(buf, len, &md5);
 675                         md5_end(hash, &md5);
 676
 677                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 678                                 secretbytes[i] ^= 0x36;
 679                                 secretbytes[i] ^= 0x5c;
 680                         }
 681
 682                         md5_begin(&md5);
 683                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 684                         md5_hash(hash, 16, &md5);
 685                         md5_end(hash, &md5);
 686
 687                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 688                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 689                         rcmsg = odata[0];
 690                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 691                         ia_present = true;
 692                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 693                                 options_valid = false;
 694                 }
 695                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 696                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 697                         // Options are not allowed on global level
 698                         options_valid = false;
 699                 }
 700         }
 701
 702         if (!options_valid || ((odata + olen) > end))
 703                 return false;
 704
 705         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 706                 return false;
 707
 708         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 709                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 710                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 711                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 712                         return false;
 713         }
 714
 715         return clientid_ok && serverid_ok;
 716 }
 717
 718
 719 int dhcpv6_poll_reconfigure(void)
 720 {
 721         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 722         if (ret != -1)
 723                 ret = dhcpv6_request(ret);
 724
 725         return ret;
 726 }
 727
 728
 729 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 730                 const void *opt, const void *end)
 731 {
 732         uint16_t otype, olen;
 733         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 734         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 735                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 736                                 odata[0] == DHCPV6_MSG_RENEW ||
 737                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 738                         msg = odata[0];
 739
 740         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 741         return msg;
 742 }
 743
 744
 745 // Collect all advertised servers
 746 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 747                 const void *opt, const void *end)
 748 {
 749         uint16_t olen, otype;
 750         uint8_t *odata, pref = 0;
 751         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 752                                         DHCPV6_SOL_MAX_RT,
 753                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 754         bool have_na = false;
 755         int have_pd = 0;
 756
 757         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 758                 if (orig == DHCPV6_MSG_SOLICIT &&
 759                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 760                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 761                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 762                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 763                 }
 764
 765                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 766                         memcpy(cand.duid, odata, olen);
 767                         cand.duid_len = olen;
 768                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 769                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 770
 771                         switch (error) {
 772                         case DHCPV6_NoPrefixAvail:
 773                                 // Status code on global level
 774                                 cand.preference -= 2000;
 775                                 break;
 776
 777                         default :
 778                                 break;
 779                         }
 780                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 781                                 cand.preference >= 0) {
 782                         cand.preference = pref = odata[0];
 783                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 784                         cand.wants_reconfigure = true;
 785                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 786                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 787                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 788                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 789                                 cand.sol_max_rt = sol_max_rt;
 790                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 791                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 792                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 793                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 794                                 cand.inf_max_rt = inf_max_rt;
 795                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 796                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 797                         uint8_t *oend = odata + olen, *d;
 798                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 799                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 800                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 801                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 802                                         have_pd = p->prefix;
 803                                 }
 804                         }
 805                 } else if (otype == DHCPV6_OPT_IA_NA) {
 806                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 807                         uint8_t *oend = odata + olen, *d;
 808                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 809                                 if (otype == DHCPV6_OPT_IA_ADDR)
 810                                         have_na = true;
 811                 }
 812         }
 813
 814         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 815                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 816                 /*
 817                  * RFC7083 states to process the SOL_MAX_RT and
 818                  * INF_MAX_RT options even if the DHCPv6 server
 819                  * did not propose any IA_NA and/or IA_PD
 820                  */
 821                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 822                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 823                 return -1;
 824         }
 825
 826         if (na_mode != IA_MODE_NONE && !have_na) {
 827                 cand.has_noaddravail = true;
 828                 cand.preference -= 1000;
 829         }
 830
 831         if (pd_mode != IA_MODE_NONE) {
 832                 if (have_pd)
 833                         cand.preference += 2000 + (128 - have_pd);
 834                 else
 835                         cand.preference -= 2000;
 836         }
 837
 838         if (cand.duid_len > 0) {
 839                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 840                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 841                 dhcpv6_add_server_cand(&cand);
 842         }
 843
 844         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 845 }
 846
 847
 848 static int dhcpv6_commit_advert(void)
 849 {
 850         return dhcpv6_promote_server_cand();
 851 }
 852
 853
 854 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 855                 const void *opt, const void *end)
 856 {
 857         dhcpv6_handle_advert(orig, rc, opt, end);
 858         if (dhcpv6_commit_advert() < 0)
 859                 return -1;
 860
 861         return dhcpv6_handle_reply(orig, rc, opt, end);
 862 }
 863
 864
 865 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 866                 const void *opt, const void *end)
 867 {
 868         uint8_t *odata;
 869         uint16_t otype, olen;
 870         uint32_t refresh = UINT32_MAX;
 871         int ret = 1;
 872         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 873
 874         odhcp6c_expire();
 875
 876         if (orig == DHCPV6_MSG_UNKNOWN) {
 877                 static time_t last_update = 0;
 878                 time_t now = odhcp6c_get_milli_time() / 1000;
 879
 880                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 881                 last_update = now;
 882
 883                 if (t1 != UINT32_MAX)
 884                         t1 -= elapsed;
 885
 886                 if (t2 != UINT32_MAX)
 887                         t2 -= elapsed;
 888
 889                 if (t3 != UINT32_MAX)
 890                         t3 -= elapsed;
 891
 892                 if (t1 < 0)
 893                         t1 = 0;
 894
 895                 if (t2 < 0)
 896                         t2 = 0;
 897
 898                 if (t3 < 0)
 899                         t3 = 0;
 900         }
 901
 902         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 903                 // Delete NA and PD we have in the state from the Advert
 904                 odhcp6c_clear_state(STATE_IA_NA);
 905                 odhcp6c_clear_state(STATE_IA_PD);
 906         }
 907
 908         if (opt) {
 909                 odhcp6c_clear_state(STATE_DNS);
 910                 odhcp6c_clear_state(STATE_SEARCH);
 911                 odhcp6c_clear_state(STATE_SNTP_IP);
 912                 odhcp6c_clear_state(STATE_NTP_IP);
 913                 odhcp6c_clear_state(STATE_NTP_FQDN);
 914                 odhcp6c_clear_state(STATE_SIP_IP);
 915                 odhcp6c_clear_state(STATE_SIP_FQDN);
 916                 odhcp6c_clear_state(STATE_AFTR_NAME);
 917         }
 918
 919         // Parse and find all matching IAs
 920         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 921                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 922                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 923                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 924
 925                         // Test ID
 926                         if (ia_hdr->iaid != 1 && otype == DHCPV6_OPT_IA_NA)
 927                                 continue;
 928
 929                         uint16_t code = DHCPV6_Success;
 930                         uint16_t stype, slen;
 931                         uint8_t *sdata;
 932                         // Get and handle status code
 933                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 934                                         stype, slen, sdata) {
 935                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 936                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 937                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 938
 939                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 940
 941                                         if (code == DHCPV6_Success)
 942                                                 continue;
 943
 944                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 945                                                 code, mdata, mlen, handled_status_codes, &ret);
 946
 947
 948                                         if (ret > 0)
 949                                                 return ret;
 950                                         break;
 951                                 }
 952                         }
 953
 954                         if (code != DHCPV6_Success)
 955                                 continue;
 956
 957                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 958                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 959                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 960                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 961                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 962
 963                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 964                 }
 965                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 966                         if (olen % 16 == 0)
 967                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 968                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 969                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 970                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 971                         if (olen % 16 == 0)
 972                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 973                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 974                         uint16_t stype, slen;
 975                         uint8_t *sdata;
 976                         // Test status and bail if error
 977                         dhcpv6_for_each_option(odata, odata + olen,
 978                                         stype, slen, sdata) {
 979                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 980                                                 stype == NTP_SRV_ADDR))
 981                                         odhcp6c_add_state(STATE_NTP_IP,
 982                                                         sdata, slen);
 983                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 984                                         odhcp6c_add_state(STATE_NTP_FQDN,
 985                                                         sdata, slen);
 986                         }
 987                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 988                         if (olen == 16)
 989                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 990                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 991                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 992                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 993                         refresh = ntohl(*((uint32_t*)odata));
 994                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 995                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 996                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 997                         if (r->protocol == 3 && r->algorithm == 1 &&
 998                                         r->reconf_type == 1)
 999                                 memcpy(reconf_key, r->key, sizeof(r->key));
1000                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1001                         size_t cur_len;
1002                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1003                         if (cur_len == 0)
1004                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1005                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1006                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1007                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1008                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1009                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1010                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1011                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1012                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1013                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1014                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1015 #ifdef EXT_CER_ID
1016                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1017                                 sizeof(struct dhcpv6_cer_id)) {
1018                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1019                         struct in6_addr any = IN6ADDR_ANY_INIT;
1020                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1021                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1022 #endif
1023                 } else if (otype != DHCPV6_OPT_CLIENTID &&
1024                                 otype != DHCPV6_OPT_SERVERID) {
1025                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
1026                                         &odata[-4], olen + 4);
1027                 }
1028         }
1029
1030         if (orig != DHCPV6_MSG_INFO_REQ) {
1031                 // Update refresh timers if no fatal status code was received
1032                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1033                         switch (orig) {
1034                         case DHCPV6_MSG_RENEW:
1035                                 // Send further renews if T1 is not set
1036                                 if (!t1)
1037                                         ret = -1;
1038                                 break;
1039                         case DHCPV6_MSG_REBIND:
1040                                 // Send further rebinds if T1 and T2 is not set
1041                                 if (!t1 && !t2)
1042                                         ret = -1;
1043                                 break;
1044
1045                         case DHCPV6_MSG_REQUEST:
1046                                 // All server candidates can be cleared if not yet bound
1047                                 if (!odhcp6c_is_bound())
1048                                         dhcpv6_clear_all_server_cand();
1049
1050                         default :
1051                                 break;
1052                         }
1053                 }
1054         }
1055         else if (ret > 0) {
1056                 // All server candidates can be cleared if not yet bound
1057                 if (!odhcp6c_is_bound())
1058                         dhcpv6_clear_all_server_cand();
1059
1060                 t1 = refresh;
1061         }
1062
1063         return ret;
1064 }
1065
1066
1067 static int dhcpv6_parse_ia(void *opt, void *end)
1068 {
1069         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1070         int parsed_ia = 0;
1071         uint32_t t1, t2;
1072         uint16_t otype, olen;
1073         uint8_t *odata;
1074
1075         t1 = ntohl(ia_hdr->t1);
1076         t2 = ntohl(ia_hdr->t2);
1077
1078         if (t1 > t2)
1079                 return 0;
1080
1081         // Update address IA
1082         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1083                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1084                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1085
1086                 entry.iaid = ia_hdr->iaid;
1087
1088                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1089                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1090                         if (olen + 4U < sizeof(*prefix))
1091                                 continue;
1092
1093                         entry.valid = ntohl(prefix->valid);
1094                         entry.preferred = ntohl(prefix->preferred);
1095
1096                         if (entry.preferred > entry.valid)
1097                                 continue;
1098
1099                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1100                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1101                         if (entry.t1 > entry.t2)
1102                                 entry.t1 = entry.t2;
1103
1104                         entry.length = prefix->prefix;
1105                         entry.target = prefix->addr;
1106                         uint16_t stype, slen;
1107                         uint8_t *sdata;
1108
1109 #ifdef EXT_PREFIX_CLASS
1110                         // Find prefix class, if any
1111                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1112                                         stype, slen, sdata)
1113                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1114                                         entry.class = sdata[0] << 8 | sdata[1];
1115 #endif
1116
1117                         // Parse PD-exclude
1118                         bool ok = true;
1119                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1120                                         odata + olen, stype, slen, sdata) {
1121                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1122                                         continue;
1123
1124                                 uint8_t elen = sdata[0];
1125                                 if (elen > 64)
1126                                         elen = 64;
1127
1128                                 if (elen <= 32 || elen <= entry.length) {
1129                                         ok = false;
1130                                         continue;
1131                                 }
1132
1133
1134                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1135                                 if (slen <= bytes) {
1136                                         ok = false;
1137                                         continue;
1138                                 }
1139
1140                                 uint32_t exclude = 0;
1141                                 do {
1142                                         exclude = exclude << 8 | sdata[bytes];
1143                                 } while (--bytes);
1144
1145                                 exclude >>= 8 - ((elen - entry.length) % 8);
1146                                 exclude <<= 64 - elen;
1147
1148                                 // Abusing router & priority fields for exclusion
1149                                 entry.router = entry.target;
1150                                 entry.router.s6_addr32[1] |= htonl(exclude);
1151                                 entry.priority = elen;
1152                         }
1153
1154                         if (ok) {
1155                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1156                                 parsed_ia++;
1157                         }
1158
1159                         entry.priority = 0;
1160                         memset(&entry.router, 0, sizeof(entry.router));
1161                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1162                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1163                         if (olen + 4U < sizeof(*addr))
1164                                 continue;
1165
1166                         entry.preferred = ntohl(addr->preferred);
1167                         entry.valid = ntohl(addr->valid);
1168
1169                         if (entry.preferred > entry.valid)
1170                                 continue;
1171
1172                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1173                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1174                         if (entry.t1 > entry.t2)
1175                                 entry.t1 = entry.t2;
1176
1177                         entry.length = 128;
1178                         entry.target = addr->addr;
1179
1180 #ifdef EXT_PREFIX_CLASS
1181                         uint16_t stype, slen;
1182                         uint8_t *sdata;
1183                         // Find prefix class, if any
1184                         dhcpv6_for_each_option(&addr[1], odata + olen,
1185                                         stype, slen, sdata)
1186                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1187                                         entry.class = sdata[0] << 8 | sdata[1];
1188 #endif
1189
1190                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1191                         parsed_ia++;
1192                 }
1193         }
1194         return parsed_ia;
1195 }
1196
1197
1198 static int dhcpv6_calc_refresh_timers(void)
1199 {
1200         struct odhcp6c_entry *e;
1201         size_t ia_na_entries, ia_pd_entries, i;
1202         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1203
1204         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1205         ia_na_entries /= sizeof(*e);
1206         for (i = 0; i < ia_na_entries; i++) {
1207                 if (e[i].t1 < l_t1)
1208                         l_t1 = e[i].t1;
1209
1210                 if (e[i].t2 < l_t2)
1211                         l_t2 = e[i].t2;
1212
1213                 if (e[i].valid > l_t3)
1214                         l_t3 = e[i].valid;
1215         }
1216
1217         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1218         ia_pd_entries /= sizeof(*e);
1219         for (i = 0; i < ia_pd_entries; i++) {
1220                 if (e[i].t1 < l_t1)
1221                         l_t1 = e[i].t1;
1222
1223                 if (e[i].t2 < l_t2)
1224                         l_t2 = e[i].t2;
1225
1226                 if (e[i].valid > l_t3)
1227                         l_t3 = e[i].valid;
1228         }
1229
1230         if (ia_pd_entries || ia_na_entries) {
1231                 t1 = l_t1;
1232                 t2 = l_t2;
1233                 t3 = l_t3;
1234         } else {
1235                 t1 = 600;
1236         }
1237
1238         return (int)(ia_pd_entries + ia_na_entries);
1239 }
1240
1241
1242 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1243                 const void *status_msg, const int len)
1244 {
1245         uint8_t buf[len + 3];
1246
1247         memset(buf, 0, sizeof(buf));
1248         if (len) {
1249                 buf[0] = '(';
1250                 memcpy(&buf[1], status_msg, len);
1251                 buf[len + 1] = ')';
1252         }
1253
1254         syslog(LOG_WARNING, "Server returned %s status %i %s",
1255                 scope, code, buf);
1256 }
1257
1258
1259 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1260                 const uint16_t code, const void *status_msg, const int len,
1261                 int *ret)
1262 {
1263         dhcpv6_log_status_code(code, "message", status_msg, len);
1264
1265         switch (code) {
1266         case DHCPV6_UnspecFail:
1267                 // Generic failure
1268                 *ret = 0;
1269                 break;
1270
1271         case DHCPV6_UseMulticast:
1272                 // TODO handle multicast status code
1273                 break;
1274
1275         case DHCPV6_NoAddrsAvail:
1276         case DHCPV6_NoPrefixAvail:
1277                 if (orig == DHCPV6_MSG_REQUEST)
1278                         *ret = 0; // Failure
1279                 break;
1280
1281         default:
1282                 break;
1283         }
1284 }
1285
1286
1287 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1288                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1289                 const void *status_msg, const int len,
1290                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1291 {
1292         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1293                 "IA_NA" : "IA_PD", status_msg, len);
1294
1295         switch (code) {
1296         case DHCPV6_NoBinding:
1297                 switch (orig) {
1298                 case DHCPV6_MSG_RENEW:
1299                 case DHCPV6_MSG_REBIND:
1300                         if ((*ret > 0) && !handled_status_codes[code])
1301                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1302                         break;
1303
1304                 default:
1305                         break;
1306                 }
1307                 break;
1308
1309         case DHCPV6_NoAddrsAvail:
1310         case DHCPV6_NoPrefixAvail:
1311                 switch (orig) {
1312                 case DHCPV6_MSG_REQUEST:
1313                         if (*ret != 0)
1314                                 *ret = 0;
1315                         break;
1316                 default:
1317                         break;
1318                 }
1319                 break;
1320
1321         case DHCPV6_NotOnLink:
1322                 // TODO handle not onlink in case of confirm
1323                 break;
1324
1325         default:
1326                 break;
1327         }
1328 }
1329
1330 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1331 {
1332         size_t cand_len, i;
1333         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1334
1335         // Remove identical duid server candidate
1336         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1337                 if (cand->duid_len == c[i].duid_len &&
1338                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1339                         free(c[i].ia_na);
1340                         free(c[i].ia_pd);
1341                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1342                         break;
1343                 }
1344         }
1345
1346         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1347                 i < cand_len / sizeof(*c); ++i) {
1348                 if (c[i].preference < cand->preference)
1349                         break;
1350         }
1351
1352         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1353 }
1354
1355 static void dhcpv6_clear_all_server_cand(void)
1356 {
1357         size_t cand_len, i;
1358         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1359
1360         // Server candidates need deep delete for IA_NA/IA_PD
1361         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1362                 free(c[i].ia_na);
1363                 free(c[i].ia_pd);
1364         }
1365         odhcp6c_clear_state(STATE_SERVER_CAND);
1366 }
1367
1368 int dhcpv6_promote_server_cand(void)
1369 {
1370         size_t cand_len;
1371         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1372         uint16_t hdr[2];
1373         int ret = (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) ?
1374                         DHCPV6_STATELESS : DHCPV6_STATEFUL;
1375
1376         // Clear lingering candidate state info
1377         odhcp6c_clear_state(STATE_SERVER_ID);
1378         odhcp6c_clear_state(STATE_IA_NA);
1379         odhcp6c_clear_state(STATE_IA_PD);
1380
1381         if (!cand_len)
1382                 return -1;
1383
1384         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1385                 na_mode = IA_MODE_NONE;
1386
1387                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1388                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1389
1390                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1391         }
1392
1393         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1394         hdr[1] = htons(cand->duid_len);
1395         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1396         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1397         accept_reconfig = cand->wants_reconfigure;
1398         if (cand->ia_na_len) {
1399                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1400                 free(cand->ia_na);
1401                 if (na_mode != IA_MODE_NONE)
1402                         ret = DHCPV6_STATEFUL;
1403         }
1404         if (cand->ia_pd_len) {
1405                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1406                 free(cand->ia_pd);
1407                 if (request_prefix)
1408                         ret = DHCPV6_STATEFUL;
1409         }
1410
1411         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1412         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1413
1414         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1415
1416         return ret;
1417 }