src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <time.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <inttypes.h>
  20 #include <stdlib.h>
  21 #include <signal.h>
  22 #include <limits.h>
  23 #include <resolv.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <syslog.h>
  27 #include <stdbool.h>
  28 #include <ctype.h>
  29 #include <sys/time.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/socket.h>
  32 #include <arpa/inet.h>
  33 #include <netinet/in.h>
  34
  35 #include <net/if.h>
  36 #include <net/ethernet.h>
  37
  38 #include "odhcp6c.h"
  39 #ifdef USE_LIBUBOX
  40 #include <libubox/md5.h>
  41 #else
  42 #include "md5.h"
  43 #endif
  44
  45
  46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  47                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  48 #define DHCPV6_CLIENT_PORT 546
  49 #define DHCPV6_SERVER_PORT 547
  50 #define DHCPV6_DUID_LLADDR 3
  51 #define DHCPV6_REQ_DELAY 1
  52
  53 #define DHCPV6_SOL_MAX_RT_MIN 60
  54 #define DHCPV6_SOL_MAX_RT_MAX 86400
  55 #define DHCPV6_INF_MAX_RT_MIN 60
  56 #define DHCPV6_INF_MAX_RT_MAX 86400
  57
  58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  59                 const uint8_t transaction[3], enum dhcpv6_msg type,
  60                 const struct in6_addr *daddr);
  61
  62 static unsigned int dhcpv6_parse_ia(void *opt, void *end);
  63
  64 static int dhcpv6_calc_refresh_timers(void);
  65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  66                 const uint16_t code, const void *status_msg, const int len,
  67                 int *ret);
  68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  69                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  70                 const void *status_msg, const int len,
  71                 bool handled_status_codes[_DHCPV6_Status_Max],
  72                 int *ret);
  73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  74 static void dhcpv6_clear_all_server_cand(void);
  75
  76 static reply_handler dhcpv6_handle_reply;
  77 static reply_handler dhcpv6_handle_advert;
  78 static reply_handler dhcpv6_handle_rebind_reply;
  79 static reply_handler dhcpv6_handle_reconfigure;
  80 static int dhcpv6_commit_advert(void);
  81
  82 // RFC 3315 - 5.5 Timeout and Delay values
  83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  84         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  85                         dhcpv6_handle_reconfigure, NULL},
  86         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  87                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  88         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  89                         dhcpv6_handle_reply, NULL},
  90         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  91                         dhcpv6_handle_reply, NULL},
  92         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  93                         dhcpv6_handle_rebind_reply, NULL},
  94         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  95         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  96         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  97                         dhcpv6_handle_reply, NULL},
  98 };
  99
 100 // Sockets
 101 static int sock = -1;
 102 static int ifindex = -1;
 103 static int64_t t1 = 0, t2 = 0, t3 = 0;
 104
 105 // IA states
 106 static int request_prefix = -1;
 107 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 108 static bool accept_reconfig = false;
 109 // Server unicast address
 110 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
 111
 112 // Reconfigure key
 113 static uint8_t reconf_key[16];
 114
 115 // client options
 116 static unsigned int client_options = 0;
 117
 118 static uint32_t ntohl_unaligned(const uint8_t *data)
 119 {
 120         uint32_t buf;
 121
 122         memcpy(&buf, data, sizeof(buf));
 123         return ntohl(buf);
 124 }
 125
 126 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 127 {
 128         client_options = options;
 129         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 130
 131         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 132         if (sock < 0)
 133                 goto failure;
 134
 135         // Detect interface
 136         struct ifreq ifr;
 137         memset(&ifr, 0, sizeof(ifr));
 138         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
 139         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 140                 goto failure;
 141
 142         ifindex = ifr.ifr_ifindex;
 143
 144         // Create client DUID
 145         size_t client_id_len;
 146         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 147         if (client_id_len == 0) {
 148                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 149                                 DHCPV6_DUID_LLADDR, 0, 1};
 150
 151                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 152                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 153
 154                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 155                 struct ifreq ifs[100], *ifp, *ifend;
 156                 struct ifconf ifc;
 157                 ifc.ifc_req = ifs;
 158                 ifc.ifc_len = sizeof(ifs);
 159
 160                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 161                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 162                         // If our interface doesn't have an address...
 163                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 164                         for (ifp = ifc.ifc_req; ifp < ifend &&
 165                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 166                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 167                                                 sizeof(ifr.ifr_name));
 168                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 169                                         continue;
 170
 171                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 172                                                 ETHER_ADDR_LEN);
 173                         }
 174                 }
 175
 176                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 177         }
 178
 179         // Create ORO
 180         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 181                 uint16_t oro[] = {
 182                         htons(DHCPV6_OPT_SIP_SERVER_D),
 183                         htons(DHCPV6_OPT_SIP_SERVER_A),
 184                         htons(DHCPV6_OPT_DNS_SERVERS),
 185                         htons(DHCPV6_OPT_DNS_DOMAIN),
 186                         htons(DHCPV6_OPT_SNTP_SERVERS),
 187                         htons(DHCPV6_OPT_NTP_SERVER),
 188                         htons(DHCPV6_OPT_AFTR_NAME),
 189                         htons(DHCPV6_OPT_PD_EXCLUDE),
 190                         htons(DHCPV6_OPT_SOL_MAX_RT),
 191                         htons(DHCPV6_OPT_INF_MAX_RT),
 192 #ifdef EXT_CER_ID
 193                         htons(DHCPV6_OPT_CER_ID),
 194 #endif
 195                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 196                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 197                         htons(DHCPV6_OPT_S46_CONT_LW),
 198                 };
 199                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 200
 201                 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST)) {
 202                         uint16_t otype = htons(DHCPV6_OPT_UNICAST);
 203
 204                         odhcp6c_add_state(STATE_ORO, &otype, sizeof(otype));
 205                 }
 206         }
 207
 208         // Configure IPv6-options
 209         int val = 1;
 210         if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
 211                 goto failure;
 212
 213         if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
 214                 goto failure;
 215
 216         if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
 217                 goto failure;
 218
 219         if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
 220                 goto failure;
 221
 222         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 223                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 224
 225         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 226                 goto failure;
 227
 228         return 0;
 229
 230 failure:
 231         if (sock >= 0)
 232                 close(sock);
 233
 234         return -1;
 235 }
 236
 237 enum {
 238         IOV_HDR=0,
 239         IOV_ORO,
 240         IOV_ORO_REFRESH,
 241         IOV_CL_ID,
 242         IOV_SRV_ID,
 243         IOV_OPTS,
 244         IOV_RECONF_ACCEPT,
 245         IOV_FQDN,
 246         IOV_HDR_IA_NA,
 247         IOV_IA_NA,
 248         IOV_IA_PD,
 249         IOV_TOTAL
 250 };
 251
 252 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 253 {
 254         int mode = DHCPV6_UNKNOWN;
 255
 256         na_mode = na;
 257         pd_mode = pd;
 258
 259         if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
 260                 mode = DHCPV6_STATELESS;
 261         else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
 262                 mode = DHCPV6_STATEFUL;
 263
 264         return mode;
 265 }
 266
 267 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 268 {
 269         // Build FQDN
 270         char fqdn_buf[256];
 271         gethostname(fqdn_buf, sizeof(fqdn_buf));
 272         struct {
 273                 uint16_t type;
 274                 uint16_t len;
 275                 uint8_t flags;
 276                 uint8_t data[256];
 277         } fqdn;
 278         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 279                         sizeof(fqdn.data), NULL, NULL);
 280         fqdn.type = htons(DHCPV6_OPT_FQDN);
 281         fqdn.len = htons(fqdn_len - 4);
 282         fqdn.flags = 0;
 283
 284         // Build Client ID
 285         size_t cl_id_len;
 286         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 287
 288         // Get Server ID
 289         size_t srv_id_len;
 290         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 291
 292         // Build IA_PDs
 293         size_t ia_pd_entries = 0, ia_pd_len = 0;
 294         uint8_t *ia_pd;
 295
 296         if (type == DHCPV6_MSG_SOLICIT) {
 297                 odhcp6c_clear_state(STATE_IA_PD);
 298                 size_t n_prefixes;
 299                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 300                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 301
 302                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 303
 304                 for (size_t i = 0; i < n_prefixes; i++) {
 305                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 306                                 htons(DHCPV6_OPT_IA_PD),
 307                                 htons(sizeof(hdr_ia_pd) - 4 +
 308                                       sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
 309                                 request_prefixes[i].iaid, 0, 0
 310                         };
 311                         struct dhcpv6_ia_prefix pref = {
 312                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 313                                 .len = htons(sizeof(pref) - 4),
 314                                 .prefix = request_prefixes[i].length
 315                         };
 316                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 317                         ia_pd_len += sizeof(hdr_ia_pd);
 318                         if (request_prefixes[i].length) {
 319                                 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 320                                 ia_pd_len += sizeof(pref);
 321                         }
 322                 }
 323         } else {
 324                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 325                 ia_pd_entries /= sizeof(*e);
 326
 327                 // we're too lazy to count our distinct IAIDs,
 328                 // so just allocate maximally needed space
 329                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 330                                         sizeof(struct dhcpv6_ia_hdr)));
 331
 332                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 333                         uint32_t iaid = e[i].iaid;
 334
 335                         // check if this is an unprocessed IAID and skip if not.
 336                         int new_iaid = 1;
 337                         for (int j = i-1; j >= 0; j--) {
 338                                 if (e[j].iaid == iaid) {
 339                                         new_iaid = 0;
 340                                         break;
 341                                 }
 342                         }
 343
 344                         if (!new_iaid)
 345                                 continue;
 346
 347                         // construct header
 348                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 349                                 htons(DHCPV6_OPT_IA_PD),
 350                                 htons(sizeof(hdr_ia_pd) - 4),
 351                                 iaid, 0, 0
 352                         };
 353
 354                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 355                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 356                         ia_pd_len += sizeof(hdr_ia_pd);
 357
 358                         for (size_t j = i; j < ia_pd_entries; j++) {
 359                                 if (e[j].iaid != iaid)
 360                                         continue;
 361
 362                                 uint8_t ex_len = 0;
 363                                 if (e[j].priority > 0)
 364                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 365
 366                                 struct dhcpv6_ia_prefix p = {
 367                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 368                                         .len = htons(sizeof(p) - 4U + ex_len),
 369                                         .prefix = e[j].length,
 370                                         .addr = e[j].target
 371                                 };
 372
 373                                 if (type == DHCPV6_MSG_REQUEST) {
 374                                         p.preferred = htonl(e[j].preferred);
 375                                         p.valid = htonl(e[j].valid);
 376                                 }
 377
 378                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 379                                 ia_pd_len += sizeof(p);
 380
 381                                 if (ex_len) {
 382                                         ia_pd[ia_pd_len++] = 0;
 383                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 384                                         ia_pd[ia_pd_len++] = 0;
 385                                         ia_pd[ia_pd_len++] = ex_len - 4;
 386                                         ia_pd[ia_pd_len++] = e[j].priority;
 387
 388                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 389                                         excl >>= (64 - e[j].priority);
 390                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 391
 392                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 393                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 394                                         ia_pd_len += ex_len - 5;
 395                                 }
 396
 397                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 398                         }
 399                 }
 400         }
 401
 402         if (ia_pd_entries > 0)
 403                 request_prefix = 1;
 404
 405         // Build IA_NAs
 406         size_t ia_na_entries, ia_na_len = 0;
 407         void *ia_na = NULL;
 408         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 409         ia_na_entries /= sizeof(*e);
 410
 411         struct dhcpv6_ia_hdr hdr_ia_na = {
 412                 htons(DHCPV6_OPT_IA_NA),
 413                 htons(sizeof(hdr_ia_na) - 4),
 414                 htonl(1), 0, 0
 415         };
 416
 417         struct dhcpv6_ia_addr pa[ia_na_entries];
 418         for (size_t i = 0; i < ia_na_entries; ++i) {
 419                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 420                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 421                 pa[i].addr = e[i].target;
 422
 423                 if (type == DHCPV6_MSG_REQUEST) {
 424                         pa[i].preferred = htonl(e[i].preferred);
 425                         pa[i].valid = htonl(e[i].valid);
 426                 } else {
 427                         pa[i].preferred = 0;
 428                         pa[i].valid = 0;
 429                 }
 430         }
 431
 432         ia_na = pa;
 433         ia_na_len = sizeof(pa);
 434         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 435
 436         // Reconfigure Accept
 437         struct {
 438                 uint16_t type;
 439                 uint16_t length;
 440         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 441
 442         // Request Information Refresh
 443         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 444
 445         // Option list
 446         size_t opts_len;
 447         void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
 448
 449         // Prepare Header
 450         size_t oro_len;
 451         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 452         struct {
 453                 uint8_t type;
 454                 uint8_t trid[3];
 455                 uint16_t elapsed_type;
 456                 uint16_t elapsed_len;
 457                 uint16_t elapsed_value;
 458                 uint16_t oro_type;
 459                 uint16_t oro_len;
 460         } hdr = {
 461                 type, {trid[0], trid[1], trid[2]},
 462                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 463                         htons((ecs > 0xffff) ? 0xffff : ecs),
 464                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 465         };
 466
 467         struct iovec iov[IOV_TOTAL] = {
 468                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 469                 [IOV_ORO] = {oro, oro_len},
 470                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 471                 [IOV_CL_ID] = {cl_id, cl_id_len},
 472                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 473                 [IOV_OPTS] = { opts, opts_len },
 474                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 475                 [IOV_FQDN] = {&fqdn, fqdn_len},
 476                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 477                 [IOV_IA_NA] = {ia_na, ia_na_len},
 478                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 479         };
 480
 481         size_t cnt = IOV_TOTAL;
 482         if (type == DHCPV6_MSG_INFO_REQ) {
 483                 cnt = 9;
 484                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 485                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 486         } else if (!request_prefix)
 487                 cnt = 13;
 488
 489         // Disable IAs if not used
 490         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 491                 iov[IOV_HDR_IA_NA].iov_len = 0;
 492
 493         if (na_mode == IA_MODE_NONE)
 494                 iov[IOV_HDR_IA_NA].iov_len = 0;
 495
 496         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 497                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 498                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 499
 500         if (!(client_options & DHCPV6_CLIENT_FQDN))
 501                 iov[IOV_FQDN].iov_len = 0;
 502
 503         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 504                 0, ALL_DHCPV6_RELAYS, ifindex};
 505         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 506                         .msg_iov = iov, .msg_iovlen = cnt};
 507
 508         switch (type) {
 509         case DHCPV6_MSG_REQUEST:
 510         case DHCPV6_MSG_RENEW:
 511         case DHCPV6_MSG_RELEASE:
 512         case DHCPV6_MSG_DECLINE:
 513                 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
 514                         odhcp6c_addr_in_scope(&server_addr)) {
 515                         srv.sin6_addr = server_addr;
 516                         if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
 517                                 srv.sin6_scope_id = 0;
 518                 }
 519                 break;
 520         default:
 521                 break;
 522         }
 523
 524         if (sendmsg(sock, &msg, 0) < 0) {
 525                 char in6_str[INET6_ADDRSTRLEN];
 526
 527                 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
 528                         inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
 529                                 in6_str, sizeof(in6_str)), strerror(errno));
 530         }
 531 }
 532
 533 static int64_t dhcpv6_rand_delay(int64_t time)
 534 {
 535         int random;
 536         odhcp6c_random(&random, sizeof(random));
 537
 538         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 539 }
 540
 541 int dhcpv6_request(enum dhcpv6_msg type)
 542 {
 543         uint8_t rc = 0;
 544         uint64_t timeout = UINT32_MAX;
 545         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 546
 547         if (retx->delay) {
 548                 struct timespec ts = {0, 0};
 549                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
 550
 551                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 552         }
 553
 554         if (type == DHCPV6_MSG_UNKNOWN)
 555                 timeout = t1;
 556         else if (type == DHCPV6_MSG_RENEW)
 557                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 558         else if (type == DHCPV6_MSG_REBIND)
 559                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 560
 561         if (timeout == 0)
 562                 return -1;
 563
 564         syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
 565                         retx->name, timeout, retx->max_rc);
 566
 567         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 568
 569         // Generate transaction ID
 570         uint8_t trid[3] = {0, 0, 0};
 571         if (type != DHCPV6_MSG_UNKNOWN)
 572                 odhcp6c_random(trid, sizeof(trid));
 573
 574         ssize_t len = -1;
 575         int64_t rto = 0;
 576
 577         do {
 578                 if (rto == 0) {
 579                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 580
 581                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 582                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 583                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 584
 585                         rto = (retx->init_timeo * 1000 + delay);
 586                 } else
 587                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 588
 589                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 590                         rto = retx->max_timeo * 1000 +
 591                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 592
 593                 // Calculate end for this round and elapsed time
 594                 uint64_t round_end = round_start + rto;
 595                 elapsed = round_start - start;
 596
 597                 // Don't wait too long if timeout differs from infinite
 598                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 599                         round_end = timeout * 1000 + start;
 600
 601                 // Built and send package
 602                 switch (type) {
 603                 case DHCPV6_MSG_UNKNOWN:
 604                         break;
 605                 default:
 606                         syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
 607                                         retx->name, elapsed, rc);
 608                         // Fall through
 609                 case DHCPV6_MSG_SOLICIT:
 610                 case DHCPV6_MSG_INFO_REQ:
 611                         dhcpv6_send(type, trid, elapsed / 10);
 612                         rc++;
 613                 }
 614
 615                 // Receive rounds
 616                 for (; len < 0 && (round_start < round_end);
 617                                 round_start = odhcp6c_get_milli_time()) {
 618                         uint8_t buf[1536];
 619                         union {
 620                                 struct cmsghdr hdr;
 621                                 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 622                         } cmsg_buf;
 623                         struct iovec iov = {buf, sizeof(buf)};
 624                         struct sockaddr_in6 addr;
 625                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 626                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
 627                                         .msg_controllen = sizeof(cmsg_buf)};
 628                         struct in6_pktinfo *pktinfo = NULL;
 629
 630                         // Check for pending signal
 631                         if (odhcp6c_signal_process())
 632                                 return -1;
 633
 634                         // Set timeout for receiving
 635                         uint64_t t = round_end - round_start;
 636                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 637                         if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 638                                         &tv, sizeof(tv)) < 0)
 639                                 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
 640                                                 strerror(errno));
 641
 642                         // Receive cycle
 643                         len = recvmsg(sock, &msg, 0);
 644                         if (len < 0)
 645                                 continue;
 646
 647                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 648                                 ch = CMSG_NXTHDR(&msg, ch)) {
 649                                 if (ch->cmsg_level == SOL_IPV6 &&
 650                                         ch->cmsg_type == IPV6_PKTINFO) {
 651                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 652                                         break;
 653                                 }
 654                         }
 655
 656                         if (pktinfo == NULL) {
 657                                 len = -1;
 658                                 continue;
 659                         }
 660
 661                         if (!dhcpv6_response_is_valid(buf, len, trid,
 662                                                         type, &pktinfo->ipi6_addr)) {
 663                                 len = -1;
 664                                 continue;
 665                         }
 666
 667                         uint8_t *opt = &buf[4];
 668                         uint8_t *opt_end = opt + len - 4;
 669
 670                         round_start = odhcp6c_get_milli_time();
 671                         elapsed = round_start - start;
 672                         syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
 673                                         elapsed);
 674
 675                         if (retx->handler_reply)
 676                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 677
 678                         if (len > 0 && round_end - round_start > 1000)
 679                                 round_end = 1000 + round_start;
 680                 }
 681
 682                 // Allow
 683                 if (retx->handler_finish)
 684                         len = retx->handler_finish();
 685         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 686                         (!retx->max_rc || rc < retx->max_rc));
 687         return len;
 688 }
 689
 690 // Message validation checks according to RFC3315 chapter 15
 691 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 692                 const uint8_t transaction[3], enum dhcpv6_msg type,
 693                 const struct in6_addr *daddr)
 694 {
 695         const struct dhcpv6_header *rep = buf;
 696         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 697                         transaction, sizeof(rep->tr_id)))
 698                 return false; // Invalid reply
 699
 700         if (type == DHCPV6_MSG_SOLICIT) {
 701                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 702                                 rep->msg_type != DHCPV6_MSG_REPLY)
 703                         return false;
 704
 705         } else if (type == DHCPV6_MSG_UNKNOWN) {
 706                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 707                         return false;
 708
 709         } else if (rep->msg_type != DHCPV6_MSG_REPLY)
 710                 return false;
 711
 712         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 713                 rcmsg = DHCPV6_MSG_UNKNOWN;
 714         uint16_t otype, olen = UINT16_MAX;
 715         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 716                 ia_present = false, options_valid = true;
 717
 718         size_t client_id_len, server_id_len;
 719         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 720         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 721
 722         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 723                 if (otype == DHCPV6_OPT_CLIENTID) {
 724                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 725                                         &odata[-4], client_id, client_id_len);
 726                 } else if (otype == DHCPV6_OPT_SERVERID) {
 727                         if (server_id_len)
 728                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 729                                                 &odata[-4], server_id, server_id_len);
 730                         else
 731                                 serverid_ok = true;
 732                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 733                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 734                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 735                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 736                                 continue;
 737
 738                         md5_ctx_t md5;
 739                         uint8_t serverhash[16], secretbytes[64];
 740                         uint32_t hash[4];
 741                         memcpy(serverhash, r->key, sizeof(serverhash));
 742                         memset(r->key, 0, sizeof(r->key));
 743
 744                         memset(secretbytes, 0, sizeof(secretbytes));
 745                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 746
 747                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 748                                 secretbytes[i] ^= 0x36;
 749
 750                         md5_begin(&md5);
 751                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 752                         md5_hash(buf, len, &md5);
 753                         md5_end(hash, &md5);
 754
 755                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 756                                 secretbytes[i] ^= 0x36;
 757                                 secretbytes[i] ^= 0x5c;
 758                         }
 759
 760                         md5_begin(&md5);
 761                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 762                         md5_hash(hash, 16, &md5);
 763                         md5_end(hash, &md5);
 764
 765                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 766                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 767                         rcmsg = odata[0];
 768                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 769                         ia_present = true;
 770                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 771                                 options_valid = false;
 772                 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 773                                 (otype == DHCPV6_OPT_PD_EXCLUDE))
 774                         // Options are not allowed on global level
 775                         options_valid = false;
 776         }
 777
 778         if (!options_valid || ((odata + olen) > end))
 779                 return false;
 780
 781         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 782                 return false;
 783
 784         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 785                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 786                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 787                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 788                         return false;
 789         }
 790
 791         return clientid_ok && serverid_ok;
 792 }
 793
 794 int dhcpv6_poll_reconfigure(void)
 795 {
 796         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 797
 798         if (ret != -1)
 799                 ret = dhcpv6_request(ret);
 800
 801         return ret;
 802 }
 803
 804 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
 805                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 806 {
 807         uint16_t otype, olen;
 808         uint8_t *odata;
 809         int msg = -1;
 810
 811         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 812                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 813                         switch (odata[0]) {
 814                         case DHCPV6_MSG_REBIND:
 815                                 if (t2 != UINT32_MAX)
 816                                         t2 = 0;
 817                         // Fall through
 818                         case DHCPV6_MSG_RENEW:
 819                                 if (t1 != UINT32_MAX)
 820                                         t1 = 0;
 821                         // Fall through
 822                         case DHCPV6_MSG_INFO_REQ:
 823                                 msg = odata[0];
 824                                 break;
 825
 826                         default:
 827                                 break;
 828                         }
 829                 }
 830         }
 831
 832         dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
 833
 834         return msg;
 835 }
 836
 837 // Collect all advertised servers
 838 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 839                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 840 {
 841         uint16_t olen, otype;
 842         uint8_t *odata, pref = 0;
 843         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 844                                         IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
 845                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 846         bool have_na = false;
 847         int have_pd = 0;
 848
 849         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 850                 if (orig == DHCPV6_MSG_SOLICIT &&
 851                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 852                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 853                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 854                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 855                 }
 856
 857                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 858                         memcpy(cand.duid, odata, olen);
 859                         cand.duid_len = olen;
 860                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 861                                 cand.preference >= 0) {
 862                         cand.preference = pref = odata[0];
 863                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
 864                         if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
 865                                 cand.server_addr = *(struct in6_addr *)odata;
 866
 867                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 868                         cand.wants_reconfigure = true;
 869                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 870                         uint32_t sol_max_rt = ntohl_unaligned(odata);
 871                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 872                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 873                                 cand.sol_max_rt = sol_max_rt;
 874
 875                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 876                         uint32_t inf_max_rt = ntohl_unaligned(odata);
 877                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 878                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 879                                 cand.inf_max_rt = inf_max_rt;
 880
 881                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix &&
 882                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 883                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 884                         uint8_t *oend = odata + olen, *d;
 885                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 886                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 887                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 888                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 889                                         have_pd = p->prefix;
 890                                 }
 891                         }
 892                 } else if (otype == DHCPV6_OPT_IA_NA &&
 893                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 894                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 895                         uint8_t *oend = odata + olen, *d;
 896
 897                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 898                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 899                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 900                                         have_na = true;
 901                         }
 902                 }
 903         }
 904
 905         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 906                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 907                 /*
 908                  * RFC7083 states to process the SOL_MAX_RT and
 909                  * INF_MAX_RT options even if the DHCPv6 server
 910                  * did not propose any IA_NA and/or IA_PD
 911                  */
 912                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 913                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 914                 return -1;
 915         }
 916
 917         if (na_mode != IA_MODE_NONE && !have_na) {
 918                 cand.has_noaddravail = true;
 919                 cand.preference -= 1000;
 920         }
 921
 922         if (pd_mode != IA_MODE_NONE) {
 923                 if (have_pd)
 924                         cand.preference += 2000 + (128 - have_pd);
 925                 else
 926                         cand.preference -= 2000;
 927         }
 928
 929         if (cand.duid_len > 0) {
 930                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 931                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 932                 dhcpv6_add_server_cand(&cand);
 933         }
 934
 935         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 936 }
 937
 938 static int dhcpv6_commit_advert(void)
 939 {
 940         return dhcpv6_promote_server_cand();
 941 }
 942
 943 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 944                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 945 {
 946         dhcpv6_handle_advert(orig, rc, opt, end, from);
 947         if (dhcpv6_commit_advert() < 0)
 948                 return -1;
 949
 950         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 951 }
 952
 953 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 954                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 955 {
 956         uint8_t *odata;
 957         uint16_t otype, olen;
 958         uint32_t refresh = 86400;
 959         int ret = 1;
 960         unsigned int updated_IAs = 0;
 961         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 962
 963         odhcp6c_expire();
 964
 965         if (orig == DHCPV6_MSG_UNKNOWN) {
 966                 static time_t last_update = 0;
 967                 time_t now = odhcp6c_get_milli_time() / 1000;
 968
 969                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 970                 last_update = now;
 971
 972                 if (t1 != UINT32_MAX)
 973                         t1 -= elapsed;
 974
 975                 if (t2 != UINT32_MAX)
 976                         t2 -= elapsed;
 977
 978                 if (t3 != UINT32_MAX)
 979                         t3 -= elapsed;
 980
 981                 if (t1 < 0)
 982                         t1 = 0;
 983
 984                 if (t2 < 0)
 985                         t2 = 0;
 986
 987                 if (t3 < 0)
 988                         t3 = 0;
 989         }
 990
 991         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 992                 // Delete NA and PD we have in the state from the Advert
 993                 odhcp6c_clear_state(STATE_IA_NA);
 994                 odhcp6c_clear_state(STATE_IA_PD);
 995         }
 996
 997         if (opt) {
 998                 odhcp6c_clear_state(STATE_DNS);
 999                 odhcp6c_clear_state(STATE_SEARCH);
1000                 odhcp6c_clear_state(STATE_SNTP_IP);
1001                 odhcp6c_clear_state(STATE_NTP_IP);
1002                 odhcp6c_clear_state(STATE_NTP_FQDN);
1003                 odhcp6c_clear_state(STATE_SIP_IP);
1004                 odhcp6c_clear_state(STATE_SIP_FQDN);
1005                 odhcp6c_clear_state(STATE_AFTR_NAME);
1006                 odhcp6c_clear_state(STATE_CER);
1007                 odhcp6c_clear_state(STATE_S46_MAPT);
1008                 odhcp6c_clear_state(STATE_S46_MAPE);
1009                 odhcp6c_clear_state(STATE_S46_LW);
1010                 odhcp6c_clear_state(STATE_PASSTHRU);
1011                 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1012
1013                 // Parse and find all matching IAs
1014                 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1015                         struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1016
1017                         if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1018                                         && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1019                                 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1020
1021                                 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1022                                         (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1023                                         continue;
1024
1025                                 // Test ID
1026                                 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1027                                         continue;
1028
1029                                 uint16_t code = DHCPV6_Success;
1030                                 uint16_t stype, slen;
1031                                 uint8_t *sdata;
1032                                 // Get and handle status code
1033                                 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1034                                                 stype, slen, sdata) {
1035                                         if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1036                                                 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1037                                                 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1038
1039                                                 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1040
1041                                                 if (code == DHCPV6_Success)
1042                                                         continue;
1043
1044                                                 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1045                                                         code, mdata, mlen, handled_status_codes, &ret);
1046
1047                                                 if (ret > 0)
1048                                                         return ret;
1049
1050                                                 break;
1051                                         }
1052                                 }
1053
1054                                 if (code != DHCPV6_Success)
1055                                         continue;
1056
1057                                 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1058                         } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1059                                 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1060                                         server_addr = *(struct in6_addr *)odata;
1061
1062                         }
1063                         else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1064                                 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1065                                 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1066                                 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1067
1068                                 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1069                         } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1070                                 if (olen % 16 == 0)
1071                                         odhcp6c_add_state(STATE_DNS, odata, olen);
1072                         } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1073                                 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1074                         else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1075                                 if (olen % 16 == 0)
1076                                         odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1077                         } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1078                                 uint16_t stype, slen;
1079                                 uint8_t *sdata;
1080                                 // Test status and bail if error
1081                                 dhcpv6_for_each_option(odata, odata + olen,
1082                                                 stype, slen, sdata) {
1083                                         if (slen == 16 && (stype == NTP_MC_ADDR ||
1084                                                         stype == NTP_SRV_ADDR))
1085                                                 odhcp6c_add_state(STATE_NTP_IP,
1086                                                                 sdata, slen);
1087                                         else if (slen > 0 && stype == NTP_SRV_FQDN)
1088                                                 odhcp6c_add_state(STATE_NTP_FQDN,
1089                                                                 sdata, slen);
1090                                 }
1091                         } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1092                                 if (olen == 16)
1093                                         odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1094                         } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1095                                 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1096                         else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1097                                 refresh = ntohl_unaligned(odata);
1098                         } else if (otype == DHCPV6_OPT_AUTH) {
1099                                 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1100                                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1101                                         if (r->protocol == 3 && r->algorithm == 1 &&
1102                                                         r->reconf_type == 1)
1103                                                 memcpy(reconf_key, r->key, sizeof(r->key));
1104                                 }
1105                         } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1106                                 size_t cur_len;
1107                                 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1108                                 if (cur_len == 0)
1109                                         odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1110                         } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1111                                 uint32_t sol_max_rt = ntohl_unaligned(odata);
1112                                 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1113                                                 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1114                                         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1115                         } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1116                                 uint32_t inf_max_rt = ntohl_unaligned(odata);
1117                                 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1118                                                 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1119                                         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1120         #ifdef EXT_CER_ID
1121                         } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1122                                         sizeof(struct dhcpv6_cer_id)) {
1123                                 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1124                                 struct in6_addr any = IN6ADDR_ANY_INIT;
1125                                 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1126                                         odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1127         #endif
1128                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1129                                 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1130                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1131                                 size_t mape_len;
1132                                 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1133                                 if (mape_len == 0)
1134                                         odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1135                         } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1136                                 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1137                         } else
1138                                 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1139
1140                         if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1141                                 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1142                 }
1143         }
1144
1145         switch (orig) {
1146         case DHCPV6_MSG_REQUEST:
1147         case DHCPV6_MSG_REBIND:
1148         case DHCPV6_MSG_RENEW:
1149                 // Update refresh timers if no fatal status code was received
1150                 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1151                         if (orig == DHCPV6_MSG_REQUEST) {
1152                                 // All server candidates can be cleared if not yet bound
1153                                 if (!odhcp6c_is_bound())
1154                                         dhcpv6_clear_all_server_cand();
1155
1156                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1157                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1158                         } else if (orig == DHCPV6_MSG_RENEW) {
1159                                 // Send further renews if T1 is not set and
1160                                 // no updated IAs
1161                                 if (!t1) {
1162                                         if (!updated_IAs)
1163                                                 ret = -1;
1164                                         else if ((t2 - t1) > 1)
1165                                                 // Grace period of 1 second
1166                                                 t1 = 1;
1167                                 }
1168
1169                         } else if (orig == DHCPV6_MSG_REBIND) {
1170                                 // Send further rebinds if T1 and T2 is not set and
1171                                 // no updated IAs
1172                                 if (!t1 && !t2) {
1173                                         if (!updated_IAs)
1174                                                 ret = -1;
1175                                         else if ((t3 - t2) > 1)
1176                                                 // Grace period of 1 second
1177                                                 t2 = 1;
1178                                 }
1179
1180                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1181                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1182                         }
1183                 }
1184                 break;
1185
1186         case DHCPV6_MSG_INFO_REQ:
1187                 if (ret > 0) {
1188                         // All server candidates can be cleared if not yet bound
1189                         if (!odhcp6c_is_bound())
1190                                 dhcpv6_clear_all_server_cand();
1191
1192                         t1 = refresh;
1193                 }
1194                 break;
1195
1196         default:
1197                 break;
1198         }
1199
1200         return ret;
1201 }
1202
1203 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1204 {
1205         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1206         unsigned int updated_IAs = 0;
1207         uint32_t t1, t2;
1208         uint16_t otype, olen;
1209         uint8_t *odata;
1210
1211         t1 = ntohl(ia_hdr->t1);
1212         t2 = ntohl(ia_hdr->t2);
1213
1214         if (t1 > t2)
1215                 return 0;
1216
1217         // Update address IA
1218         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1219                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1220                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1221
1222                 entry.iaid = ia_hdr->iaid;
1223
1224                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1225                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1226                         if (olen + 4U < sizeof(*prefix))
1227                                 continue;
1228
1229                         entry.valid = ntohl(prefix->valid);
1230                         entry.preferred = ntohl(prefix->preferred);
1231
1232                         if (entry.preferred > entry.valid)
1233                                 continue;
1234
1235                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1236                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1237                         if (entry.t1 > entry.t2)
1238                                 entry.t1 = entry.t2;
1239
1240                         entry.length = prefix->prefix;
1241                         entry.target = prefix->addr;
1242                         uint16_t stype, slen;
1243                         uint8_t *sdata;
1244
1245                         // Parse PD-exclude
1246                         bool ok = true;
1247                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1248                                         odata + olen, stype, slen, sdata) {
1249                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1250                                         continue;
1251
1252                                 uint8_t elen = sdata[0];
1253                                 if (elen > 64)
1254                                         elen = 64;
1255
1256                                 if (entry.length < 32 || elen <= entry.length) {
1257                                         ok = false;
1258                                         continue;
1259                                 }
1260
1261                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1262                                 if (slen <= bytes) {
1263                                         ok = false;
1264                                         continue;
1265                                 }
1266
1267                                 uint32_t exclude = 0;
1268                                 do {
1269                                         exclude = exclude << 8 | sdata[bytes];
1270                                 } while (--bytes);
1271
1272                                 exclude >>= 8 - ((elen - entry.length) % 8);
1273                                 exclude <<= 64 - elen;
1274
1275                                 // Abusing router & priority fields for exclusion
1276                                 entry.router = entry.target;
1277                                 entry.router.s6_addr32[1] |= htonl(exclude);
1278                                 entry.priority = elen;
1279                         }
1280
1281                         if (ok) {
1282                                 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1283                                         updated_IAs++;
1284                         }
1285
1286                         entry.priority = 0;
1287                         memset(&entry.router, 0, sizeof(entry.router));
1288                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1289                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1290                         if (olen + 4U < sizeof(*addr))
1291                                 continue;
1292
1293                         entry.preferred = ntohl(addr->preferred);
1294                         entry.valid = ntohl(addr->valid);
1295
1296                         if (entry.preferred > entry.valid)
1297                                 continue;
1298
1299                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1300                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1301                         if (entry.t1 > entry.t2)
1302                                 entry.t1 = entry.t2;
1303
1304                         entry.length = 128;
1305                         entry.target = addr->addr;
1306
1307                         if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1308                                 updated_IAs++;
1309                 }
1310         }
1311         return updated_IAs;
1312 }
1313
1314 static int dhcpv6_calc_refresh_timers(void)
1315 {
1316         struct odhcp6c_entry *e;
1317         size_t ia_na_entries, ia_pd_entries, i;
1318         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1319
1320         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1321         ia_na_entries /= sizeof(*e);
1322
1323         for (i = 0; i < ia_na_entries; i++) {
1324                 if (e[i].t1 < l_t1)
1325                         l_t1 = e[i].t1;
1326
1327                 if (e[i].t2 < l_t2)
1328                         l_t2 = e[i].t2;
1329
1330                 if (e[i].valid > l_t3)
1331                         l_t3 = e[i].valid;
1332         }
1333
1334         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1335         ia_pd_entries /= sizeof(*e);
1336
1337         for (i = 0; i < ia_pd_entries; i++) {
1338                 if (e[i].t1 < l_t1)
1339                         l_t1 = e[i].t1;
1340
1341                 if (e[i].t2 < l_t2)
1342                         l_t2 = e[i].t2;
1343
1344                 if (e[i].valid > l_t3)
1345                         l_t3 = e[i].valid;
1346         }
1347
1348         if (ia_pd_entries || ia_na_entries) {
1349                 t1 = l_t1;
1350                 t2 = l_t2;
1351                 t3 = l_t3;
1352         }
1353
1354         return (int)(ia_pd_entries + ia_na_entries);
1355 }
1356
1357 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1358                 const void *status_msg, int len)
1359 {
1360         const char *src = status_msg;
1361         char buf[len + 3];
1362         char *dst = buf;
1363
1364         if (len) {
1365                 *dst++ = '(';
1366                 while (len--) {
1367                         *dst = isprint((unsigned char)*src) ? *src : '?';
1368                         src++;
1369                         dst++;
1370                 }
1371                 *dst++ = ')';
1372         }
1373
1374         *dst = 0;
1375
1376         syslog(LOG_WARNING, "Server returned %s status %i %s",
1377                 scope, code, buf);
1378 }
1379
1380 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1381                 const uint16_t code, const void *status_msg, const int len,
1382                 int *ret)
1383 {
1384         dhcpv6_log_status_code(code, "message", status_msg, len);
1385
1386         switch (code) {
1387         case DHCPV6_UnspecFail:
1388                 // Generic failure
1389                 *ret = 0;
1390                 break;
1391
1392         case DHCPV6_UseMulticast:
1393                 switch(orig) {
1394                 case DHCPV6_MSG_REQUEST:
1395                 case DHCPV6_MSG_RENEW:
1396                 case DHCPV6_MSG_RELEASE:
1397                 case DHCPV6_MSG_DECLINE:
1398                         // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1399                         server_addr = in6addr_any;
1400                         *ret = 0;
1401                         break;
1402                 default:
1403                         break;
1404                 }
1405                 break;
1406
1407         case DHCPV6_NoAddrsAvail:
1408         case DHCPV6_NoPrefixAvail:
1409                 if (orig == DHCPV6_MSG_REQUEST)
1410                         *ret = 0; // Failure
1411                 break;
1412
1413         default:
1414                 break;
1415         }
1416 }
1417
1418 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1419                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1420                 const void *status_msg, const int len,
1421                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1422 {
1423         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1424                 "IA_NA" : "IA_PD", status_msg, len);
1425
1426         switch (code) {
1427         case DHCPV6_NoBinding:
1428                 switch (orig) {
1429                 case DHCPV6_MSG_RENEW:
1430                 case DHCPV6_MSG_REBIND:
1431                         if ((*ret > 0) && !handled_status_codes[code])
1432                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1433                         break;
1434
1435                 default:
1436                         break;
1437                 }
1438                 break;
1439
1440         default:
1441                 *ret = 0;
1442                 break;
1443         }
1444 }
1445
1446 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1447 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1448 {
1449         size_t cand_len, i;
1450         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1451
1452         // Remove identical duid server candidate
1453         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1454                 if (cand->duid_len == c[i].duid_len &&
1455                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1456                         free(c[i].ia_na);
1457                         free(c[i].ia_pd);
1458                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1459                         break;
1460                 }
1461         }
1462
1463         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1464                 i < cand_len / sizeof(*c); ++i) {
1465                 if (c[i].preference < cand->preference)
1466                         break;
1467         }
1468
1469         if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1470                 free(cand->ia_na);
1471                 free(cand->ia_pd);
1472         }
1473 }
1474
1475 static void dhcpv6_clear_all_server_cand(void)
1476 {
1477         size_t cand_len, i;
1478         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1479
1480         // Server candidates need deep delete for IA_NA/IA_PD
1481         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1482                 free(c[i].ia_na);
1483                 free(c[i].ia_pd);
1484         }
1485         odhcp6c_clear_state(STATE_SERVER_CAND);
1486 }
1487
1488 int dhcpv6_promote_server_cand(void)
1489 {
1490         size_t cand_len;
1491         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1492         uint16_t hdr[2];
1493         int ret = DHCPV6_STATELESS;
1494
1495         // Clear lingering candidate state info
1496         odhcp6c_clear_state(STATE_SERVER_ID);
1497         odhcp6c_clear_state(STATE_IA_NA);
1498         odhcp6c_clear_state(STATE_IA_PD);
1499
1500         if (!cand_len)
1501                 return -1;
1502
1503         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1504                 na_mode = IA_MODE_NONE;
1505
1506                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1507                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1508
1509                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1510         }
1511
1512         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1513         hdr[1] = htons(cand->duid_len);
1514         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1515         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1516         accept_reconfig = cand->wants_reconfigure;
1517
1518         if (cand->ia_na_len) {
1519                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1520                 free(cand->ia_na);
1521                 if (na_mode != IA_MODE_NONE)
1522                         ret = DHCPV6_STATEFUL;
1523         }
1524
1525         if (cand->ia_pd_len) {
1526                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1527                 free(cand->ia_pd);
1528                 if (request_prefix)
1529                         ret = DHCPV6_STATEFUL;
1530         }
1531
1532         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1533         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1534
1535         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1536
1537         return ret;
1538 }