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                 };
 180                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 181         }
 182
 183         // Configure IPv6-options
 184         int val = 1;
 185         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 186         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 187         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 188         val = 0;
 189         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
 190         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 191
 192         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 193                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 194         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 195                 return -1;
 196
 197         return 0;
 198 }
 199
 200 enum {
 201         IOV_HDR=0,
 202         IOV_ORO,
 203         IOV_ORO_REFRESH,
 204         IOV_CL_ID,
 205         IOV_SRV_ID,
 206         IOV_VENDOR_CLASS_HDR,
 207         IOV_VENDOR_CLASS,
 208         IOV_USER_CLASS_HDR,
 209         IOV_USER_CLASS,
 210         IOV_RECONF_ACCEPT,
 211         IOV_FQDN,
 212         IOV_HDR_IA_NA,
 213         IOV_IA_NA,
 214         IOV_IA_PD,
 215         IOV_TOTAL
 216 };
 217
 218 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 219 {
 220         na_mode = na;
 221         pd_mode = pd;
 222 }
 223
 224 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 225 {
 226         // Build FQDN
 227         char fqdn_buf[256];
 228         gethostname(fqdn_buf, sizeof(fqdn_buf));
 229         struct {
 230                 uint16_t type;
 231                 uint16_t len;
 232                 uint8_t flags;
 233                 uint8_t data[256];
 234         } fqdn;
 235         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 236                         sizeof(fqdn.data), NULL, NULL);
 237         fqdn.type = htons(DHCPV6_OPT_FQDN);
 238         fqdn.len = htons(fqdn_len - 4);
 239         fqdn.flags = 0;
 240
 241
 242         // Build Client ID
 243         size_t cl_id_len;
 244         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 245
 246         // Get Server ID
 247         size_t srv_id_len;
 248         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 249
 250         // Build IA_PDs
 251         size_t ia_pd_entries, ia_pd_len = 0;
 252         uint8_t *ia_pd;
 253
 254         if (type == DHCPV6_MSG_SOLICIT) {
 255                 odhcp6c_clear_state(STATE_IA_PD);
 256                 size_t n_prefixes;
 257                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 258                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 259
 260                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 261
 262                 for (size_t i = 0; i < n_prefixes; i++) {
 263                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 264                                 htons(DHCPV6_OPT_IA_PD),
 265                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 266                                 request_prefixes[i].iaid, 0, 0
 267                         };
 268                         struct dhcpv6_ia_prefix pref = {
 269                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 270                                 .len = htons(25), .prefix = request_prefixes[i].length
 271                         };
 272                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 273                         ia_pd_len += sizeof(hdr_ia_pd);
 274                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 275                         ia_pd_len += sizeof(pref);
 276                 }
 277         } else {
 278                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 279                 ia_pd_entries /= sizeof(*e);
 280
 281                 // we're too lazy to count our distinct IAIDs,
 282                 // so just allocate maximally needed space
 283                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 284                                         sizeof(struct dhcpv6_ia_hdr)));
 285
 286                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 287                         uint32_t iaid = e[i].iaid;
 288
 289                         // check if this is an unprocessed IAID and skip if not.
 290                         int new_iaid = 1;
 291                         for (int j = i-1; j >= 0; j--) {
 292                                 if (e[j].iaid == iaid) {
 293                                         new_iaid = 0;
 294                                         break;
 295                                 }
 296                         }
 297
 298                         if (!new_iaid)
 299                                 continue;
 300
 301                         // construct header
 302                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 303                                 htons(DHCPV6_OPT_IA_PD),
 304                                 htons(sizeof(hdr_ia_pd) - 4),
 305                                 iaid, 0, 0
 306                         };
 307
 308                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 309                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 310                         ia_pd_len += sizeof(hdr_ia_pd);
 311
 312                         for (size_t j = i; j < ia_pd_entries; j++) {
 313                                 if (e[j].iaid != iaid)
 314                                         continue;
 315
 316                                 uint8_t ex_len = 0;
 317                                 if (e[j].priority > 0)
 318                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 319
 320                                 struct dhcpv6_ia_prefix p = {
 321                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 322                                         .len = htons(sizeof(p) - 4U + ex_len),
 323                                         .prefix = e[j].length,
 324                                         .addr = e[j].target
 325                                 };
 326
 327                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 328                                 ia_pd_len += sizeof(p);
 329
 330                                 if (ex_len) {
 331                                         ia_pd[ia_pd_len++] = 0;
 332                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 333                                         ia_pd[ia_pd_len++] = 0;
 334                                         ia_pd[ia_pd_len++] = ex_len - 4;
 335                                         ia_pd[ia_pd_len++] = e[j].priority;
 336
 337                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 338                                         excl >>= (64 - e[j].priority);
 339                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 340
 341                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 342                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 343                                         ia_pd_len += ex_len - 5;
 344                                 }
 345
 346                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 347                         }
 348                 }
 349         }
 350
 351         if (ia_pd_entries > 0)
 352                 request_prefix = 1;
 353
 354         // Build IA_NAs
 355         size_t ia_na_entries, ia_na_len = 0;
 356         void *ia_na = NULL;
 357         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 358         ia_na_entries /= sizeof(*e);
 359
 360         struct dhcpv6_ia_hdr hdr_ia_na = {
 361                 htons(DHCPV6_OPT_IA_NA),
 362                 htons(sizeof(hdr_ia_na) - 4),
 363                 1, 0, 0
 364         };
 365
 366         struct dhcpv6_ia_addr pa[ia_na_entries];
 367         for (size_t i = 0; i < ia_na_entries; ++i) {
 368                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 369                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 370                 pa[i].addr = e[i].target;
 371                 pa[i].preferred = 0;
 372                 pa[i].valid = 0;
 373         }
 374
 375         ia_na = pa;
 376         ia_na_len = sizeof(pa);
 377         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 378
 379         // Reconfigure Accept
 380         struct {
 381                 uint16_t type;
 382                 uint16_t length;
 383         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 384
 385         // Request Information Refresh
 386         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 387
 388         // Build vendor-class option
 389         size_t vendor_class_len, user_class_len;
 390         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 391         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 392
 393         struct {
 394                 uint16_t type;
 395                 uint16_t length;
 396         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 397
 398         struct {
 399                 uint16_t type;
 400                 uint16_t length;
 401         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 402
 403         // Prepare Header
 404         size_t oro_len;
 405         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 406         struct {
 407                 uint8_t type;
 408                 uint8_t trid[3];
 409                 uint16_t elapsed_type;
 410                 uint16_t elapsed_len;
 411                 uint16_t elapsed_value;
 412                 uint16_t oro_type;
 413                 uint16_t oro_len;
 414         } hdr = {
 415                 type, {trid[0], trid[1], trid[2]},
 416                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 417                         htons((ecs > 0xffff) ? 0xffff : ecs),
 418                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 419         };
 420
 421         struct iovec iov[IOV_TOTAL] = {
 422                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 423                 [IOV_ORO] = {oro, oro_len},
 424                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 425                 [IOV_CL_ID] = {cl_id, cl_id_len},
 426                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 427                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 428                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 429                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 430                 [IOV_USER_CLASS] = {user_class, user_class_len},
 431                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 432                 [IOV_FQDN] = {&fqdn, fqdn_len},
 433                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 434                 [IOV_IA_NA] = {ia_na, ia_na_len},
 435                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 436         };
 437
 438         size_t cnt = IOV_TOTAL;
 439         if (type == DHCPV6_MSG_INFO_REQ) {
 440                 cnt = 9;
 441                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 442                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 443         } else if (!request_prefix) {
 444                 cnt = 13;
 445         }
 446
 447         // Disable IAs if not used
 448         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 449                 iov[IOV_HDR_IA_NA].iov_len = 0;
 450
 451         if (na_mode == IA_MODE_NONE)
 452                 iov[IOV_HDR_IA_NA].iov_len = 0;
 453
 454         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 455                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 456                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 457
 458         if (!(client_options & DHCPV6_CLIENT_FQDN))
 459                 iov[IOV_FQDN].iov_len = 0;
 460
 461         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 462                 0, ALL_DHCPV6_RELAYS, ifindex};
 463         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 464
 465         sendmsg(sock, &msg, 0);
 466 }
 467
 468
 469 static int64_t dhcpv6_rand_delay(int64_t time)
 470 {
 471         int random;
 472         odhcp6c_random(&random, sizeof(random));
 473         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 474 }
 475
 476
 477 int dhcpv6_request(enum dhcpv6_msg type)
 478 {
 479         uint8_t rc = 0;
 480         uint64_t timeout = UINT32_MAX;
 481         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 482
 483         if (retx->delay) {
 484                 struct timespec ts = {0, 0};
 485                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 486                 nanosleep(&ts, NULL);
 487         }
 488
 489         if (type == DHCPV6_MSG_UNKNOWN)
 490                 timeout = t1;
 491         else if (type == DHCPV6_MSG_RENEW)
 492                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 493         else if (type == DHCPV6_MSG_REBIND)
 494                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 495
 496         if (timeout == 0)
 497                 return -1;
 498
 499         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 500                         retx->name, (unsigned long long)timeout, retx->max_rc);
 501
 502         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 503
 504         // Generate transaction ID
 505         uint8_t trid[3] = {0, 0, 0};
 506         if (type != DHCPV6_MSG_UNKNOWN)
 507                 odhcp6c_random(trid, sizeof(trid));
 508         ssize_t len = -1;
 509         int64_t rto = 0;
 510
 511         do {
 512                 if (rto == 0) {
 513                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 514
 515                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 516                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 517                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 518
 519                         rto = (retx->init_timeo * 1000 + delay);
 520                 }
 521                 else
 522                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 523
 524                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 525                         rto = retx->max_timeo * 1000 +
 526                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 527
 528                 // Calculate end for this round and elapsed time
 529                 uint64_t round_end = round_start + rto;
 530                 elapsed = round_start - start;
 531
 532                 // Don't wait too long if timeout differs from infinite
 533                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 534                         round_end = timeout * 1000 + start;
 535
 536                 // Built and send package
 537                 if (type != DHCPV6_MSG_UNKNOWN) {
 538                         if (type != DHCPV6_MSG_SOLICIT)
 539                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 540                                                 retx->name, (unsigned long long)elapsed, rc);
 541                         dhcpv6_send(type, trid, elapsed / 10);
 542                         rc++;
 543                 }
 544
 545                 // Receive rounds
 546                 for (; len < 0 && (round_start < round_end);
 547                                 round_start = odhcp6c_get_milli_time()) {
 548                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 549                         struct iovec iov = {buf, sizeof(buf)};
 550                         struct msghdr msg = {NULL, 0, &iov, 1,
 551                                         cmsg_buf, sizeof(cmsg_buf), 0};
 552                         struct in6_pktinfo *pktinfo = NULL;
 553
 554                         // Check for pending signal
 555                         if (odhcp6c_signal_process())
 556                                 return -1;
 557
 558                         // Set timeout for receiving
 559                         uint64_t t = round_end - round_start;
 560                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 561                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 562                                         &tv, sizeof(tv));
 563
 564                         // Receive cycle
 565                         len = recvmsg(sock, &msg, 0);
 566                         if (len < 0)
 567                                 continue;
 568
 569                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 570                                 ch = CMSG_NXTHDR(&msg, ch)) {
 571                                 if (ch->cmsg_level == SOL_IPV6 &&
 572                                         ch->cmsg_type == IPV6_PKTINFO) {
 573                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 574                                         break;
 575                                 }
 576                         }
 577
 578                         if (pktinfo == NULL) {
 579                                 len = -1;
 580                                 continue;
 581                         }
 582
 583                         if (!dhcpv6_response_is_valid(buf, len, trid,
 584                                                         type, &pktinfo->ipi6_addr)) {
 585                                 len = -1;
 586                                 continue;
 587                         }
 588
 589                         uint8_t *opt = &buf[4];
 590                         uint8_t *opt_end = opt + len - 4;
 591
 592                         round_start = odhcp6c_get_milli_time();
 593                         elapsed = round_start - start;
 594                         syslog(LOG_NOTICE, "Got a valid reply after "
 595                                         "%llums", (unsigned long long)elapsed);
 596
 597                         if (retx->handler_reply)
 598                                 len = retx->handler_reply(type, rc, opt, opt_end);
 599
 600                         if (len > 0 && round_end - round_start > 1000)
 601                                 round_end = 1000 + round_start;
 602                 }
 603
 604                 // Allow
 605                 if (retx->handler_finish)
 606                         len = retx->handler_finish();
 607         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 608                         (!retx->max_rc || rc < retx->max_rc));
 609         return len;
 610 }
 611
 612 // Message validation checks according to RFC3315 chapter 15
 613 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 614                 const uint8_t transaction[3], enum dhcpv6_msg type,
 615                 const struct in6_addr *daddr)
 616 {
 617         const struct dhcpv6_header *rep = buf;
 618         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 619                         transaction, sizeof(rep->tr_id)))
 620                 return false; // Invalid reply
 621
 622         if (type == DHCPV6_MSG_SOLICIT) {
 623                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 624                                 rep->msg_type != DHCPV6_MSG_REPLY)
 625                         return false;
 626         } else if (type == DHCPV6_MSG_UNKNOWN) {
 627                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 628                         return false;
 629         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 630                 return false;
 631         }
 632
 633         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 634                 rcmsg = DHCPV6_MSG_UNKNOWN;
 635         uint16_t otype, olen = UINT16_MAX;
 636         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 637                 ia_present = false, options_valid = true;
 638
 639         size_t client_id_len, server_id_len;
 640         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 641         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 642
 643         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 644                 if (otype == DHCPV6_OPT_CLIENTID) {
 645                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 646                                         &odata[-4], client_id, client_id_len);
 647                 } else if (otype == DHCPV6_OPT_SERVERID) {
 648                         if (server_id_len)
 649                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 650                                                 &odata[-4], server_id, server_id_len);
 651                         else
 652                                 serverid_ok = true;
 653                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 654                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 655                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 656                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 657                                 continue;
 658
 659                         md5_ctx_t md5;
 660                         uint8_t serverhash[16], secretbytes[64], hash[16];
 661                         memcpy(serverhash, r->key, sizeof(serverhash));
 662                         memset(r->key, 0, sizeof(r->key));
 663
 664                         memset(secretbytes, 0, sizeof(secretbytes));
 665                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 666
 667                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 668                                 secretbytes[i] ^= 0x36;
 669
 670                         md5_begin(&md5);
 671                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 672                         md5_hash(buf, len, &md5);
 673                         md5_end(hash, &md5);
 674
 675                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 676                                 secretbytes[i] ^= 0x36;
 677                                 secretbytes[i] ^= 0x5c;
 678                         }
 679
 680                         md5_begin(&md5);
 681                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 682                         md5_hash(hash, 16, &md5);
 683                         md5_end(hash, &md5);
 684
 685                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 686                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 687                         rcmsg = odata[0];
 688                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 689                         ia_present = true;
 690                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 691                                 options_valid = false;
 692                 }
 693                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 694                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 695                         // Options are not allowed on global level
 696                         options_valid = false;
 697                 }
 698         }
 699
 700         if (!options_valid || ((odata + olen) > end))
 701                 return false;
 702
 703         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 704                 return false;
 705
 706         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 707                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 708                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 709                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 710                         return false;
 711         }
 712
 713         return clientid_ok && serverid_ok;
 714 }
 715
 716
 717 int dhcpv6_poll_reconfigure(void)
 718 {
 719         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 720         if (ret != -1)
 721                 ret = dhcpv6_request(ret);
 722
 723         return ret;
 724 }
 725
 726
 727 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 728                 const void *opt, const void *end)
 729 {
 730         uint16_t otype, olen;
 731         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 732         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 733                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 734                                 odata[0] == DHCPV6_MSG_RENEW ||
 735                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 736                         msg = odata[0];
 737
 738         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 739         return msg;
 740 }
 741
 742
 743 // Collect all advertised servers
 744 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 745                 const void *opt, const void *end)
 746 {
 747         uint16_t olen, otype;
 748         uint8_t *odata, pref = 0;
 749         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 750                                         DHCPV6_SOL_MAX_RT,
 751                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 752         bool have_na = false;
 753         int have_pd = 0;
 754
 755         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 756                 if (orig == DHCPV6_MSG_SOLICIT &&
 757                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 758                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 759                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 760                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 761                 }
 762
 763                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 764                         memcpy(cand.duid, odata, olen);
 765                         cand.duid_len = olen;
 766                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 767                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 768
 769                         switch (error) {
 770                         case DHCPV6_NoPrefixAvail:
 771                                 // Status code on global level
 772                                 cand.preference -= 2000;
 773                                 break;
 774
 775                         default :
 776                                 break;
 777                         }
 778                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 779                                 cand.preference >= 0) {
 780                         cand.preference = pref = odata[0];
 781                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 782                         cand.wants_reconfigure = true;
 783                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 784                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 785                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 786                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 787                                 cand.sol_max_rt = sol_max_rt;
 788                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 789                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 790                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 791                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 792                                 cand.inf_max_rt = inf_max_rt;
 793                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 794                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 795                         uint8_t *oend = odata + olen, *d;
 796                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 797                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 798                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 799                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 800                                         have_pd = p->prefix;
 801                                 }
 802                         }
 803                 } else if (otype == DHCPV6_OPT_IA_NA) {
 804                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 805                         uint8_t *oend = odata + olen, *d;
 806                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 807                                 if (otype == DHCPV6_OPT_IA_ADDR)
 808                                         have_na = true;
 809                 }
 810         }
 811
 812         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 813                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 814                 /*
 815                  * RFC7083 states to process the SOL_MAX_RT and
 816                  * INF_MAX_RT options even if the DHCPv6 server
 817                  * did not propose any IA_NA and/or IA_PD
 818                  */
 819                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 820                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 821                 return -1;
 822         }
 823
 824         if (na_mode != IA_MODE_NONE && !have_na) {
 825                 cand.has_noaddravail = true;
 826                 cand.preference -= 1000;
 827         }
 828
 829         if (pd_mode != IA_MODE_NONE) {
 830                 if (have_pd)
 831                         cand.preference += 2000 + (128 - have_pd);
 832                 else
 833                         cand.preference -= 2000;
 834         }
 835
 836         if (cand.duid_len > 0) {
 837                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 838                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 839                 dhcpv6_add_server_cand(&cand);
 840         }
 841
 842         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 843 }
 844
 845
 846 static int dhcpv6_commit_advert(void)
 847 {
 848         return dhcpv6_promote_server_cand();
 849 }
 850
 851
 852 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 853                 const void *opt, const void *end)
 854 {
 855         dhcpv6_handle_advert(orig, rc, opt, end);
 856         if (dhcpv6_commit_advert() < 0)
 857                 return -1;
 858
 859         return dhcpv6_handle_reply(orig, rc, opt, end);
 860 }
 861
 862
 863 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 864                 const void *opt, const void *end)
 865 {
 866         uint8_t *odata;
 867         uint16_t otype, olen;
 868         uint32_t refresh = UINT32_MAX;
 869         int ret = 1;
 870         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 871
 872         odhcp6c_expire();
 873
 874         if (orig == DHCPV6_MSG_UNKNOWN) {
 875                 static time_t last_update = 0;
 876                 time_t now = odhcp6c_get_milli_time() / 1000;
 877
 878                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 879                 last_update = now;
 880
 881                 if (t1 != UINT32_MAX)
 882                         t1 -= elapsed;
 883
 884                 if (t2 != UINT32_MAX)
 885                         t2 -= elapsed;
 886
 887                 if (t3 != UINT32_MAX)
 888                         t3 -= elapsed;
 889
 890                 if (t1 < 0)
 891                         t1 = 0;
 892
 893                 if (t2 < 0)
 894                         t2 = 0;
 895
 896                 if (t3 < 0)
 897                         t3 = 0;
 898         }
 899
 900         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 901                 // Delete NA and PD we have in the state from the Advert
 902                 odhcp6c_clear_state(STATE_IA_NA);
 903                 odhcp6c_clear_state(STATE_IA_PD);
 904         }
 905
 906         if (opt) {
 907                 odhcp6c_clear_state(STATE_DNS);
 908                 odhcp6c_clear_state(STATE_SEARCH);
 909                 odhcp6c_clear_state(STATE_SNTP_IP);
 910                 odhcp6c_clear_state(STATE_NTP_IP);
 911                 odhcp6c_clear_state(STATE_NTP_FQDN);
 912                 odhcp6c_clear_state(STATE_SIP_IP);
 913                 odhcp6c_clear_state(STATE_SIP_FQDN);
 914                 odhcp6c_clear_state(STATE_AFTR_NAME);
 915         }
 916
 917         // Parse and find all matching IAs
 918         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 919                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 920                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 921                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 922
 923                         // Test ID
 924                         if (ia_hdr->iaid != 1 && otype == DHCPV6_OPT_IA_NA)
 925                                 continue;
 926
 927                         uint16_t code = DHCPV6_Success;
 928                         uint16_t stype, slen;
 929                         uint8_t *sdata;
 930                         // Get and handle status code
 931                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 932                                         stype, slen, sdata) {
 933                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 934                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 935                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 936
 937                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 938
 939                                         if (code == DHCPV6_Success)
 940                                                 continue;
 941
 942                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 943                                                 code, mdata, mlen, handled_status_codes, &ret);
 944
 945
 946                                         if (ret > 0)
 947                                                 return ret;
 948                                         break;
 949                                 }
 950                         }
 951
 952                         if (code != DHCPV6_Success)
 953                                 continue;
 954
 955                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 956                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 957                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 958                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 959                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 960
 961                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 962                 }
 963                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 964                         if (olen % 16 == 0)
 965                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 966                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 967                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 968                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 969                         if (olen % 16 == 0)
 970                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 971                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 972                         uint16_t stype, slen;
 973                         uint8_t *sdata;
 974                         // Test status and bail if error
 975                         dhcpv6_for_each_option(odata, odata + olen,
 976                                         stype, slen, sdata) {
 977                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 978                                                 stype == NTP_SRV_ADDR))
 979                                         odhcp6c_add_state(STATE_NTP_IP,
 980                                                         sdata, slen);
 981                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 982                                         odhcp6c_add_state(STATE_NTP_FQDN,
 983                                                         sdata, slen);
 984                         }
 985                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 986                         if (olen == 16)
 987                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 988                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 989                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 990                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 991                         refresh = ntohl(*((uint32_t*)odata));
 992                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 993                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 994                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 995                         if (r->protocol == 3 && r->algorithm == 1 &&
 996                                         r->reconf_type == 1)
 997                                 memcpy(reconf_key, r->key, sizeof(r->key));
 998                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
 999                         size_t cur_len;
1000                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1001                         if (cur_len == 0)
1002                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1003                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1004                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1005                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1006                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1007                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1008                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1009                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1010                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1011                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1012                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1013                 }else if (otype != DHCPV6_OPT_CLIENTID &&
1014                                 otype != DHCPV6_OPT_SERVERID) {
1015                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
1016                                         &odata[-4], olen + 4);
1017                 }
1018         }
1019
1020         if (orig != DHCPV6_MSG_INFO_REQ) {
1021                 // Update refresh timers if no fatal status code was received
1022                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1023                         switch (orig) {
1024                         case DHCPV6_MSG_RENEW:
1025                                 // Send further renews if T1 is not set
1026                                 if (!t1)
1027                                         ret = -1;
1028                                 break;
1029                         case DHCPV6_MSG_REBIND:
1030                                 // Send further rebinds if T1 and T2 is not set
1031                                 if (!t1 && !t2)
1032                                         ret = -1;
1033                                 break;
1034
1035                         case DHCPV6_MSG_REQUEST:
1036                                 // All server candidates can be cleared if not yet bound
1037                                 if (!odhcp6c_is_bound())
1038                                         dhcpv6_clear_all_server_cand();
1039
1040                         default :
1041                                 break;
1042                         }
1043                 }
1044         }
1045         else if (ret > 0) {
1046                 // All server candidates can be cleared if not yet bound
1047                 if (!odhcp6c_is_bound())
1048                         dhcpv6_clear_all_server_cand();
1049
1050                 t1 = refresh;
1051         }
1052
1053         return ret;
1054 }
1055
1056
1057 static int dhcpv6_parse_ia(void *opt, void *end)
1058 {
1059         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1060         int parsed_ia = 0;
1061         uint32_t t1, t2;
1062         uint16_t otype, olen;
1063         uint8_t *odata;
1064
1065         t1 = ntohl(ia_hdr->t1);
1066         t2 = ntohl(ia_hdr->t2);
1067
1068         if (t1 > t2)
1069                 return 0;
1070
1071         // Update address IA
1072         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1073                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1074                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1075
1076                 entry.iaid = ia_hdr->iaid;
1077
1078                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1079                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1080                         if (olen + 4U < sizeof(*prefix))
1081                                 continue;
1082
1083                         entry.valid = ntohl(prefix->valid);
1084                         entry.preferred = ntohl(prefix->preferred);
1085
1086                         if (entry.preferred > entry.valid)
1087                                 continue;
1088
1089                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1090                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1091                         if (entry.t1 > entry.t2)
1092                                 entry.t1 = entry.t2;
1093
1094                         entry.length = prefix->prefix;
1095                         entry.target = prefix->addr;
1096                         uint16_t stype, slen;
1097                         uint8_t *sdata;
1098
1099 #ifdef EXT_PREFIX_CLASS
1100                         // Find prefix class, if any
1101                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1102                                         stype, slen, sdata)
1103                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1104                                         entry.class = sdata[0] << 8 | sdata[1];
1105 #endif
1106
1107                         // Parse PD-exclude
1108                         bool ok = true;
1109                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1110                                         odata + olen, stype, slen, sdata) {
1111                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1112                                         continue;
1113
1114                                 uint8_t elen = sdata[0];
1115                                 if (elen > 64)
1116                                         elen = 64;
1117
1118                                 if (elen <= 32 || elen <= entry.length) {
1119                                         ok = false;
1120                                         continue;
1121                                 }
1122
1123
1124                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1125                                 if (slen <= bytes) {
1126                                         ok = false;
1127                                         continue;
1128                                 }
1129
1130                                 uint32_t exclude = 0;
1131                                 do {
1132                                         exclude = exclude << 8 | sdata[bytes];
1133                                 } while (--bytes);
1134
1135                                 exclude >>= 8 - ((elen - entry.length) % 8);
1136                                 exclude <<= 64 - elen;
1137
1138                                 // Abusing router & priority fields for exclusion
1139                                 entry.router = entry.target;
1140                                 entry.router.s6_addr32[1] |= htonl(exclude);
1141                                 entry.priority = elen;
1142                         }
1143
1144                         if (ok) {
1145                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1146                                 parsed_ia++;
1147                         }
1148
1149                         entry.priority = 0;
1150                         memset(&entry.router, 0, sizeof(entry.router));
1151                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1152                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1153                         if (olen + 4U < sizeof(*addr))
1154                                 continue;
1155
1156                         entry.preferred = ntohl(addr->preferred);
1157                         entry.valid = ntohl(addr->valid);
1158
1159                         if (entry.preferred > entry.valid)
1160                                 continue;
1161
1162                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1163                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1164                         if (entry.t1 > entry.t2)
1165                                 entry.t1 = entry.t2;
1166
1167                         entry.length = 128;
1168                         entry.target = addr->addr;
1169
1170 #ifdef EXT_PREFIX_CLASS
1171                         uint16_t stype, slen;
1172                         uint8_t *sdata;
1173                         // Find prefix class, if any
1174                         dhcpv6_for_each_option(&addr[1], odata + olen,
1175                                         stype, slen, sdata)
1176                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1177                                         entry.class = sdata[0] << 8 | sdata[1];
1178 #endif
1179
1180                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1181                         parsed_ia++;
1182                 }
1183         }
1184         return parsed_ia;
1185 }
1186
1187
1188 static int dhcpv6_calc_refresh_timers(void)
1189 {
1190         struct odhcp6c_entry *e;
1191         size_t ia_na_entries, ia_pd_entries, i;
1192         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1193
1194         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1195         ia_na_entries /= sizeof(*e);
1196         for (i = 0; i < ia_na_entries; i++) {
1197                 if (e[i].t1 < l_t1)
1198                         l_t1 = e[i].t1;
1199
1200                 if (e[i].t2 < l_t2)
1201                         l_t2 = e[i].t2;
1202
1203                 if (e[i].valid > l_t3)
1204                         l_t3 = e[i].valid;
1205         }
1206
1207         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1208         ia_pd_entries /= sizeof(*e);
1209         for (i = 0; i < ia_pd_entries; i++) {
1210                 if (e[i].t1 < l_t1)
1211                         l_t1 = e[i].t1;
1212
1213                 if (e[i].t2 < l_t2)
1214                         l_t2 = e[i].t2;
1215
1216                 if (e[i].valid > l_t3)
1217                         l_t3 = e[i].valid;
1218         }
1219
1220         if (ia_pd_entries || ia_na_entries) {
1221                 t1 = l_t1;
1222                 t2 = l_t2;
1223                 t3 = l_t3;
1224         } else {
1225                 t1 = 600;
1226         }
1227
1228         return (int)(ia_pd_entries + ia_na_entries);
1229 }
1230
1231
1232 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1233                 const void *status_msg, const int len)
1234 {
1235         uint8_t buf[len + 3];
1236
1237         memset(buf, 0, sizeof(buf));
1238         if (len) {
1239                 buf[0] = '(';
1240                 memcpy(&buf[1], status_msg, len);
1241                 buf[len + 1] = ')';
1242         }
1243
1244         syslog(LOG_WARNING, "Server returned %s status %i %s",
1245                 scope, code, buf);
1246 }
1247
1248
1249 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1250                 const uint16_t code, const void *status_msg, const int len,
1251                 int *ret)
1252 {
1253         dhcpv6_log_status_code(code, "message", status_msg, len);
1254
1255         switch (code) {
1256         case DHCPV6_UnspecFail:
1257                 // Generic failure
1258                 *ret = 0;
1259                 break;
1260
1261         case DHCPV6_UseMulticast:
1262                 // TODO handle multicast status code
1263                 break;
1264
1265         case DHCPV6_NoAddrsAvail:
1266         case DHCPV6_NoPrefixAvail:
1267                 if (orig == DHCPV6_MSG_REQUEST)
1268                         *ret = 0; // Failure
1269                 break;
1270
1271         default:
1272                 break;
1273         }
1274 }
1275
1276
1277 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1278                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1279                 const void *status_msg, const int len,
1280                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1281 {
1282         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1283                 "IA_NA" : "IA_PD", status_msg, len);
1284
1285         switch (code) {
1286         case DHCPV6_NoBinding:
1287                 switch (orig) {
1288                 case DHCPV6_MSG_RENEW:
1289                 case DHCPV6_MSG_REBIND:
1290                         if ((*ret > 0) && !handled_status_codes[code])
1291                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1292                         break;
1293
1294                 default:
1295                         break;
1296                 }
1297                 break;
1298
1299         case DHCPV6_NoAddrsAvail:
1300         case DHCPV6_NoPrefixAvail:
1301                 switch (orig) {
1302                 case DHCPV6_MSG_REQUEST:
1303                         if (*ret != 0)
1304                                 *ret = 0;
1305                         break;
1306                 default:
1307                         break;
1308                 }
1309                 break;
1310
1311         case DHCPV6_NotOnLink:
1312                 // TODO handle not onlink in case of confirm
1313                 break;
1314
1315         default:
1316                 break;
1317         }
1318 }
1319
1320 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1321 {
1322         size_t cand_len, i;
1323         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1324
1325         // Remove identical duid server candidate
1326         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1327                 if (cand->duid_len == c[i].duid_len &&
1328                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1329                         free(c[i].ia_na);
1330                         free(c[i].ia_pd);
1331                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1332                         break;
1333                 }
1334         }
1335
1336         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1337                 i < cand_len / sizeof(*c); ++i) {
1338                 if (c[i].preference < cand->preference)
1339                         break;
1340         }
1341
1342         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1343 }
1344
1345 static void dhcpv6_clear_all_server_cand(void)
1346 {
1347         size_t cand_len, i;
1348         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1349
1350         // Server candidates need deep delete for IA_NA/IA_PD
1351         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1352                 free(c[i].ia_na);
1353                 free(c[i].ia_pd);
1354         }
1355         odhcp6c_clear_state(STATE_SERVER_CAND);
1356 }
1357
1358 int dhcpv6_promote_server_cand(void)
1359 {
1360         size_t cand_len;
1361         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1362         uint16_t hdr[2];
1363         int ret = (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) ?
1364                         DHCPV6_STATELESS : DHCPV6_STATEFUL;
1365
1366         // Clear lingering candidate state info
1367         odhcp6c_clear_state(STATE_SERVER_ID);
1368         odhcp6c_clear_state(STATE_IA_NA);
1369         odhcp6c_clear_state(STATE_IA_PD);
1370
1371         if (!cand_len)
1372                 return -1;
1373
1374         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1375                 na_mode = IA_MODE_NONE;
1376
1377                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1378                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1379
1380                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1381         }
1382
1383         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1384         hdr[1] = htons(cand->duid_len);
1385         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1386         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1387         accept_reconfig = cand->wants_reconfigure;
1388         if (cand->ia_na_len) {
1389                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1390                 free(cand->ia_na);
1391                 if (na_mode != IA_MODE_NONE)
1392                         ret = DHCPV6_STATEFUL;
1393         }
1394         if (cand->ia_pd_len) {
1395                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1396                 free(cand->ia_pd);
1397                 if (request_prefix)
1398                         ret = DHCPV6_STATEFUL;
1399         }
1400
1401         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1402         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1403
1404         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1405
1406         return ret;
1407 }