src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <fcntl.h>
  17 #include <errno.h>
  18 #include <stdlib.h>
  19 #include <signal.h>
  20 #include <limits.h>
  21 #include <resolv.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <syslog.h>
  25 #include <stdbool.h>
  26 #include <sys/time.h>
  27 #include <sys/ioctl.h>
  28 #include <sys/socket.h>
  29 #include <netinet/in.h>
  30
  31 #include <net/if.h>
  32 #include <net/ethernet.h>
  33
  34 #include "odhcp6c.h"
  35 #include "md5.h"
  36
  37
  38 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  39                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  40 #define DHCPV6_CLIENT_PORT 546
  41 #define DHCPV6_SERVER_PORT 547
  42 #define DHCPV6_DUID_LLADDR 3
  43 #define DHCPV6_REQ_DELAY 1
  44
  45 #define DHCPV6_SOL_MAX_RT_MIN 60
  46 #define DHCPV6_SOL_MAX_RT_MAX 86400
  47 #define DHCPV6_INF_MAX_RT_MIN 60
  48 #define DHCPV6_INF_MAX_RT_MAX 86400
  49
  50 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  51                 const uint8_t transaction[3], enum dhcpv6_msg type,
  52                 const struct in6_addr *daddr);
  53
  54 static int dhcpv6_parse_ia(void *opt, void *end);
  55
  56 static int dhcpv6_calc_refresh_timers(void);
  57 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  58                 const uint16_t code, const void *status_msg, const int len,
  59                 int *ret);
  60 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  61                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  62                 const void *status_msg, const int len,
  63                 bool handled_status_codes[_DHCPV6_Status_Max],
  64                 int *ret);
  65 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  66 static void dhcpv6_clear_all_server_cand(void);
  67
  68 static reply_handler dhcpv6_handle_reply;
  69 static reply_handler dhcpv6_handle_advert;
  70 static reply_handler dhcpv6_handle_rebind_reply;
  71 static reply_handler dhcpv6_handle_reconfigure;
  72 static int dhcpv6_commit_advert(void);
  73
  74
  75
  76 // RFC 3315 - 5.5 Timeout and Delay values
  77 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  78         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  79                         dhcpv6_handle_reconfigure, NULL},
  80         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  81                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  82         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  83                         dhcpv6_handle_reply, NULL},
  84         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  85                         dhcpv6_handle_reply, NULL},
  86         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  87                         dhcpv6_handle_rebind_reply, NULL},
  88         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  89         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  90         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  91                         dhcpv6_handle_reply, NULL},
  92 };
  93
  94
  95 // Sockets
  96 static int sock = -1;
  97 static int ifindex = -1;
  98 static int64_t t1 = 0, t2 = 0, t3 = 0;
  99
 100 // IA states
 101 static int request_prefix = -1;
 102 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 103 static bool accept_reconfig = false;
 104
 105 // Reconfigure key
 106 static uint8_t reconf_key[16];
 107
 108 // client options
 109 static unsigned int client_options = 0;
 110
 111
 112 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 113 {
 114         client_options = options;
 115         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 116
 117         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 118         if (sock < 0)
 119                 return -1;
 120
 121         // Detect interface
 122         struct ifreq ifr;
 123         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 124         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 125                 return -1;
 126         ifindex = ifr.ifr_ifindex;
 127
 128         // Create client DUID
 129         size_t client_id_len;
 130         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 131         if (client_id_len == 0) {
 132                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 133                                 DHCPV6_DUID_LLADDR, 0, 1};
 134
 135                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 136                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 137
 138                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 139                 struct ifreq ifs[100], *ifp, *ifend;
 140                 struct ifconf ifc;
 141                 ifc.ifc_req = ifs;
 142                 ifc.ifc_len = sizeof(ifs);
 143
 144                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 145                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 146                         // If our interface doesn't have an address...
 147                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 148                         for (ifp = ifc.ifc_req; ifp < ifend &&
 149                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 150                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 151                                                 sizeof(ifr.ifr_name));
 152                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 153                                         continue;
 154
 155                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 156                                                 ETHER_ADDR_LEN);
 157                         }
 158                 }
 159
 160                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 161         }
 162
 163         // Create ORO
 164         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 165                 uint16_t oro[] = {
 166                         htons(DHCPV6_OPT_SIP_SERVER_D),
 167                         htons(DHCPV6_OPT_SIP_SERVER_A),
 168                         htons(DHCPV6_OPT_DNS_SERVERS),
 169                         htons(DHCPV6_OPT_DNS_DOMAIN),
 170                         htons(DHCPV6_OPT_SNTP_SERVERS),
 171                         htons(DHCPV6_OPT_NTP_SERVER),
 172                         htons(DHCPV6_OPT_AFTR_NAME),
 173                         htons(DHCPV6_OPT_PD_EXCLUDE),
 174                         htons(DHCPV6_OPT_SOL_MAX_RT),
 175                         htons(DHCPV6_OPT_INF_MAX_RT),
 176 #ifdef EXT_PREFIX_CLASS
 177                         htons(DHCPV6_OPT_PREFIX_CLASS),
 178 #endif
 179 #ifdef EXT_CER_ID
 180                         htons(DHCPV6_OPT_CER_ID),
 181 #endif
 182                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 183                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 184                         htons(DHCPV6_OPT_S46_CONT_LW),
 185                 };
 186                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 187         }
 188
 189         // Configure IPv6-options
 190         int val = 1;
 191         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 192         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 193         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 194         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 195
 196         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 197                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 198         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 199                 return -1;
 200
 201         return 0;
 202 }
 203
 204 enum {
 205         IOV_HDR=0,
 206         IOV_ORO,
 207         IOV_ORO_REFRESH,
 208         IOV_CL_ID,
 209         IOV_SRV_ID,
 210         IOV_VENDOR_CLASS_HDR,
 211         IOV_VENDOR_CLASS,
 212         IOV_USER_CLASS_HDR,
 213         IOV_USER_CLASS,
 214         IOV_RECONF_ACCEPT,
 215         IOV_FQDN,
 216         IOV_HDR_IA_NA,
 217         IOV_IA_NA,
 218         IOV_IA_PD,
 219         IOV_TOTAL
 220 };
 221
 222 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 223 {
 224         na_mode = na;
 225         pd_mode = pd;
 226 }
 227
 228 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 229 {
 230         // Build FQDN
 231         char fqdn_buf[256];
 232         gethostname(fqdn_buf, sizeof(fqdn_buf));
 233         struct {
 234                 uint16_t type;
 235                 uint16_t len;
 236                 uint8_t flags;
 237                 uint8_t data[256];
 238         } fqdn;
 239         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 240                         sizeof(fqdn.data), NULL, NULL);
 241         fqdn.type = htons(DHCPV6_OPT_FQDN);
 242         fqdn.len = htons(fqdn_len - 4);
 243         fqdn.flags = 0;
 244
 245
 246         // Build Client ID
 247         size_t cl_id_len;
 248         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 249
 250         // Get Server ID
 251         size_t srv_id_len;
 252         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 253
 254         // Build IA_PDs
 255         size_t ia_pd_entries = 0, ia_pd_len = 0;
 256         uint8_t *ia_pd;
 257
 258         if (type == DHCPV6_MSG_SOLICIT) {
 259                 odhcp6c_clear_state(STATE_IA_PD);
 260                 size_t n_prefixes;
 261                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 262                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 263
 264                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 265
 266                 for (size_t i = 0; i < n_prefixes; i++) {
 267                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 268                                 htons(DHCPV6_OPT_IA_PD),
 269                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 270                                 request_prefixes[i].iaid, 0, 0
 271                         };
 272                         struct dhcpv6_ia_prefix pref = {
 273                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 274                                 .len = htons(25), .prefix = request_prefixes[i].length
 275                         };
 276                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 277                         ia_pd_len += sizeof(hdr_ia_pd);
 278                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 279                         ia_pd_len += sizeof(pref);
 280                 }
 281         } else {
 282                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 283                 ia_pd_entries /= sizeof(*e);
 284
 285                 // we're too lazy to count our distinct IAIDs,
 286                 // so just allocate maximally needed space
 287                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 288                                         sizeof(struct dhcpv6_ia_hdr)));
 289
 290                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 291                         uint32_t iaid = e[i].iaid;
 292
 293                         // check if this is an unprocessed IAID and skip if not.
 294                         int new_iaid = 1;
 295                         for (int j = i-1; j >= 0; j--) {
 296                                 if (e[j].iaid == iaid) {
 297                                         new_iaid = 0;
 298                                         break;
 299                                 }
 300                         }
 301
 302                         if (!new_iaid)
 303                                 continue;
 304
 305                         // construct header
 306                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 307                                 htons(DHCPV6_OPT_IA_PD),
 308                                 htons(sizeof(hdr_ia_pd) - 4),
 309                                 iaid, 0, 0
 310                         };
 311
 312                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 313                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 314                         ia_pd_len += sizeof(hdr_ia_pd);
 315
 316                         for (size_t j = i; j < ia_pd_entries; j++) {
 317                                 if (e[j].iaid != iaid)
 318                                         continue;
 319
 320                                 uint8_t ex_len = 0;
 321                                 if (e[j].priority > 0)
 322                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 323
 324                                 struct dhcpv6_ia_prefix p = {
 325                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 326                                         .len = htons(sizeof(p) - 4U + ex_len),
 327                                         .prefix = e[j].length,
 328                                         .addr = e[j].target
 329                                 };
 330
 331                                 if (type == DHCPV6_MSG_REQUEST) {
 332                                         p.preferred = htonl(e[j].preferred);
 333                                         p.valid = htonl(e[j].valid);
 334                                 }
 335
 336                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 337                                 ia_pd_len += sizeof(p);
 338
 339                                 if (ex_len) {
 340                                         ia_pd[ia_pd_len++] = 0;
 341                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 342                                         ia_pd[ia_pd_len++] = 0;
 343                                         ia_pd[ia_pd_len++] = ex_len - 4;
 344                                         ia_pd[ia_pd_len++] = e[j].priority;
 345
 346                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 347                                         excl >>= (64 - e[j].priority);
 348                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 349
 350                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 351                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 352                                         ia_pd_len += ex_len - 5;
 353                                 }
 354
 355                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 356                         }
 357                 }
 358         }
 359
 360         if (ia_pd_entries > 0)
 361                 request_prefix = 1;
 362
 363         // Build IA_NAs
 364         size_t ia_na_entries, ia_na_len = 0;
 365         void *ia_na = NULL;
 366         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 367         ia_na_entries /= sizeof(*e);
 368
 369         struct dhcpv6_ia_hdr hdr_ia_na = {
 370                 htons(DHCPV6_OPT_IA_NA),
 371                 htons(sizeof(hdr_ia_na) - 4),
 372                 htonl(1), 0, 0
 373         };
 374
 375         struct dhcpv6_ia_addr pa[ia_na_entries];
 376         for (size_t i = 0; i < ia_na_entries; ++i) {
 377                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 378                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 379                 pa[i].addr = e[i].target;
 380
 381                 if (type == DHCPV6_MSG_REQUEST) {
 382                         pa[i].preferred = htonl(e[i].preferred);
 383                         pa[i].valid = htonl(e[i].valid);
 384                 } else {
 385                         pa[i].preferred = 0;
 386                         pa[i].valid = 0;
 387                 }
 388         }
 389
 390         ia_na = pa;
 391         ia_na_len = sizeof(pa);
 392         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 393
 394         // Reconfigure Accept
 395         struct {
 396                 uint16_t type;
 397                 uint16_t length;
 398         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 399
 400         // Request Information Refresh
 401         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 402
 403         // Build vendor-class option
 404         size_t vendor_class_len, user_class_len;
 405         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 406         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 407
 408         struct {
 409                 uint16_t type;
 410                 uint16_t length;
 411         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 412
 413         struct {
 414                 uint16_t type;
 415                 uint16_t length;
 416         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 417
 418         // Prepare Header
 419         size_t oro_len;
 420         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 421         struct {
 422                 uint8_t type;
 423                 uint8_t trid[3];
 424                 uint16_t elapsed_type;
 425                 uint16_t elapsed_len;
 426                 uint16_t elapsed_value;
 427                 uint16_t oro_type;
 428                 uint16_t oro_len;
 429         } hdr = {
 430                 type, {trid[0], trid[1], trid[2]},
 431                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 432                         htons((ecs > 0xffff) ? 0xffff : ecs),
 433                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 434         };
 435
 436         struct iovec iov[IOV_TOTAL] = {
 437                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 438                 [IOV_ORO] = {oro, oro_len},
 439                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 440                 [IOV_CL_ID] = {cl_id, cl_id_len},
 441                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 442                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 443                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 444                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 445                 [IOV_USER_CLASS] = {user_class, user_class_len},
 446                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 447                 [IOV_FQDN] = {&fqdn, fqdn_len},
 448                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 449                 [IOV_IA_NA] = {ia_na, ia_na_len},
 450                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 451         };
 452
 453         size_t cnt = IOV_TOTAL;
 454         if (type == DHCPV6_MSG_INFO_REQ) {
 455                 cnt = 9;
 456                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 457                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 458         } else if (!request_prefix) {
 459                 cnt = 13;
 460         }
 461
 462         // Disable IAs if not used
 463         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 464                 iov[IOV_HDR_IA_NA].iov_len = 0;
 465
 466         if (na_mode == IA_MODE_NONE)
 467                 iov[IOV_HDR_IA_NA].iov_len = 0;
 468
 469         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 470                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 471                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 472
 473         if (!(client_options & DHCPV6_CLIENT_FQDN))
 474                 iov[IOV_FQDN].iov_len = 0;
 475
 476         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 477                 0, ALL_DHCPV6_RELAYS, ifindex};
 478         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 479                         .msg_iov = iov, .msg_iovlen = cnt};
 480
 481         sendmsg(sock, &msg, 0);
 482 }
 483
 484
 485 static int64_t dhcpv6_rand_delay(int64_t time)
 486 {
 487         int random;
 488         odhcp6c_random(&random, sizeof(random));
 489         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 490 }
 491
 492
 493 int dhcpv6_request(enum dhcpv6_msg type)
 494 {
 495         uint8_t rc = 0;
 496         uint64_t timeout = UINT32_MAX;
 497         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 498
 499         if (retx->delay) {
 500                 struct timespec ts = {0, 0};
 501                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
 502                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 503         }
 504
 505         if (type == DHCPV6_MSG_UNKNOWN)
 506                 timeout = t1;
 507         else if (type == DHCPV6_MSG_RENEW)
 508                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 509         else if (type == DHCPV6_MSG_REBIND)
 510                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 511
 512         if (timeout == 0)
 513                 return -1;
 514
 515         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 516                         retx->name, (unsigned long long)timeout, retx->max_rc);
 517
 518         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 519
 520         // Generate transaction ID
 521         uint8_t trid[3] = {0, 0, 0};
 522         if (type != DHCPV6_MSG_UNKNOWN)
 523                 odhcp6c_random(trid, sizeof(trid));
 524         ssize_t len = -1;
 525         int64_t rto = 0;
 526
 527         do {
 528                 if (rto == 0) {
 529                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 530
 531                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 532                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 533                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 534
 535                         rto = (retx->init_timeo * 1000 + delay);
 536                 }
 537                 else
 538                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 539
 540                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 541                         rto = retx->max_timeo * 1000 +
 542                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 543
 544                 // Calculate end for this round and elapsed time
 545                 uint64_t round_end = round_start + rto;
 546                 elapsed = round_start - start;
 547
 548                 // Don't wait too long if timeout differs from infinite
 549                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 550                         round_end = timeout * 1000 + start;
 551
 552                 // Built and send package
 553                 if (type != DHCPV6_MSG_UNKNOWN) {
 554                         if (type != DHCPV6_MSG_SOLICIT)
 555                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 556                                                 retx->name, (unsigned long long)elapsed, rc);
 557                         dhcpv6_send(type, trid, elapsed / 10);
 558                         rc++;
 559                 }
 560
 561                 // Receive rounds
 562                 for (; len < 0 && (round_start < round_end);
 563                                 round_start = odhcp6c_get_milli_time()) {
 564                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 565                         struct iovec iov = {buf, sizeof(buf)};
 566                         struct sockaddr_in6 addr;
 567                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 568                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
 569                                         .msg_controllen = sizeof(cmsg_buf)};
 570                         struct in6_pktinfo *pktinfo = NULL;
 571
 572
 573                         // Check for pending signal
 574                         if (odhcp6c_signal_process())
 575                                 return -1;
 576
 577                         // Set timeout for receiving
 578                         uint64_t t = round_end - round_start;
 579                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 580                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 581                                         &tv, sizeof(tv));
 582
 583                         // Receive cycle
 584                         len = recvmsg(sock, &msg, 0);
 585                         if (len < 0)
 586                                 continue;
 587
 588                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 589                                 ch = CMSG_NXTHDR(&msg, ch)) {
 590                                 if (ch->cmsg_level == SOL_IPV6 &&
 591                                         ch->cmsg_type == IPV6_PKTINFO) {
 592                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 593                                         break;
 594                                 }
 595                         }
 596
 597                         if (pktinfo == NULL) {
 598                                 len = -1;
 599                                 continue;
 600                         }
 601
 602                         if (!dhcpv6_response_is_valid(buf, len, trid,
 603                                                         type, &pktinfo->ipi6_addr)) {
 604                                 len = -1;
 605                                 continue;
 606                         }
 607
 608                         uint8_t *opt = &buf[4];
 609                         uint8_t *opt_end = opt + len - 4;
 610
 611                         round_start = odhcp6c_get_milli_time();
 612                         elapsed = round_start - start;
 613                         syslog(LOG_NOTICE, "Got a valid reply after "
 614                                         "%llums", (unsigned long long)elapsed);
 615
 616                         if (retx->handler_reply)
 617                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 618
 619                         if (len > 0 && round_end - round_start > 1000)
 620                                 round_end = 1000 + round_start;
 621                 }
 622
 623                 // Allow
 624                 if (retx->handler_finish)
 625                         len = retx->handler_finish();
 626         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 627                         (!retx->max_rc || rc < retx->max_rc));
 628         return len;
 629 }
 630
 631 // Message validation checks according to RFC3315 chapter 15
 632 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 633                 const uint8_t transaction[3], enum dhcpv6_msg type,
 634                 const struct in6_addr *daddr)
 635 {
 636         const struct dhcpv6_header *rep = buf;
 637         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 638                         transaction, sizeof(rep->tr_id)))
 639                 return false; // Invalid reply
 640
 641         if (type == DHCPV6_MSG_SOLICIT) {
 642                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 643                                 rep->msg_type != DHCPV6_MSG_REPLY)
 644                         return false;
 645         } else if (type == DHCPV6_MSG_UNKNOWN) {
 646                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 647                         return false;
 648         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 649                 return false;
 650         }
 651
 652         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 653                 rcmsg = DHCPV6_MSG_UNKNOWN;
 654         uint16_t otype, olen = UINT16_MAX;
 655         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 656                 ia_present = false, options_valid = true;
 657
 658         size_t client_id_len, server_id_len;
 659         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 660         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 661
 662         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 663                 if (otype == DHCPV6_OPT_CLIENTID) {
 664                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 665                                         &odata[-4], client_id, client_id_len);
 666                 } else if (otype == DHCPV6_OPT_SERVERID) {
 667                         if (server_id_len)
 668                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 669                                                 &odata[-4], server_id, server_id_len);
 670                         else
 671                                 serverid_ok = true;
 672                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 673                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 674                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 675                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 676                                 continue;
 677
 678                         md5_ctx_t md5;
 679                         uint8_t serverhash[16], secretbytes[64], hash[16];
 680                         memcpy(serverhash, r->key, sizeof(serverhash));
 681                         memset(r->key, 0, sizeof(r->key));
 682
 683                         memset(secretbytes, 0, sizeof(secretbytes));
 684                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 685
 686                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 687                                 secretbytes[i] ^= 0x36;
 688
 689                         md5_begin(&md5);
 690                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 691                         md5_hash(buf, len, &md5);
 692                         md5_end(hash, &md5);
 693
 694                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 695                                 secretbytes[i] ^= 0x36;
 696                                 secretbytes[i] ^= 0x5c;
 697                         }
 698
 699                         md5_begin(&md5);
 700                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 701                         md5_hash(hash, 16, &md5);
 702                         md5_end(hash, &md5);
 703
 704                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 705                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 706                         rcmsg = odata[0];
 707                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 708                         ia_present = true;
 709                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 710                                 options_valid = false;
 711                 }
 712                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 713                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 714                         // Options are not allowed on global level
 715                         options_valid = false;
 716                 }
 717         }
 718
 719         if (!options_valid || ((odata + olen) > end))
 720                 return false;
 721
 722         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 723                 return false;
 724
 725         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 726                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 727                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 728                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 729                         return false;
 730         }
 731
 732         return clientid_ok && serverid_ok;
 733 }
 734
 735
 736 int dhcpv6_poll_reconfigure(void)
 737 {
 738         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 739         if (ret != -1)
 740                 ret = dhcpv6_request(ret);
 741
 742         return ret;
 743 }
 744
 745
 746 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 747                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 748 {
 749         uint16_t otype, olen;
 750         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 751         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 752                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 753                                 odata[0] == DHCPV6_MSG_RENEW ||
 754                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 755                         msg = odata[0];
 756
 757         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 758         return msg;
 759 }
 760
 761
 762 // Collect all advertised servers
 763 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 764                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 765 {
 766         uint16_t olen, otype;
 767         uint8_t *odata, pref = 0;
 768         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 769                                         DHCPV6_SOL_MAX_RT,
 770                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 771         bool have_na = false;
 772         int have_pd = 0;
 773
 774         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 775                 if (orig == DHCPV6_MSG_SOLICIT &&
 776                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 777                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 778                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 779                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 780                 }
 781
 782                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 783                         memcpy(cand.duid, odata, olen);
 784                         cand.duid_len = olen;
 785                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 786                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 787
 788                         switch (error) {
 789                         case DHCPV6_NoPrefixAvail:
 790                                 // Status code on global level
 791                                 cand.preference -= 2000;
 792                                 break;
 793
 794                         default :
 795                                 break;
 796                         }
 797                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 798                                 cand.preference >= 0) {
 799                         cand.preference = pref = odata[0];
 800                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 801                         cand.wants_reconfigure = true;
 802                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 803                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 804                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 805                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 806                                 cand.sol_max_rt = sol_max_rt;
 807                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 808                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 809                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 810                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 811                                 cand.inf_max_rt = inf_max_rt;
 812                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 813                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 814                         uint8_t *oend = odata + olen, *d;
 815                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 816                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 817                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 818                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 819                                         have_pd = p->prefix;
 820                                 }
 821                         }
 822                 } else if (otype == DHCPV6_OPT_IA_NA) {
 823                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 824                         uint8_t *oend = odata + olen, *d;
 825                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 826                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 827                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 828                                         have_na = true;
 829                 }
 830         }
 831
 832         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 833                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 834                 /*
 835                  * RFC7083 states to process the SOL_MAX_RT and
 836                  * INF_MAX_RT options even if the DHCPv6 server
 837                  * did not propose any IA_NA and/or IA_PD
 838                  */
 839                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 840                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 841                 return -1;
 842         }
 843
 844         if (na_mode != IA_MODE_NONE && !have_na) {
 845                 cand.has_noaddravail = true;
 846                 cand.preference -= 1000;
 847         }
 848
 849         if (pd_mode != IA_MODE_NONE) {
 850                 if (have_pd)
 851                         cand.preference += 2000 + (128 - have_pd);
 852                 else
 853                         cand.preference -= 2000;
 854         }
 855
 856         if (cand.duid_len > 0) {
 857                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 858                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 859                 dhcpv6_add_server_cand(&cand);
 860         }
 861
 862         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 863 }
 864
 865
 866 static int dhcpv6_commit_advert(void)
 867 {
 868         return dhcpv6_promote_server_cand();
 869 }
 870
 871
 872 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 873                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 874 {
 875         dhcpv6_handle_advert(orig, rc, opt, end, from);
 876         if (dhcpv6_commit_advert() < 0)
 877                 return -1;
 878
 879         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 880 }
 881
 882
 883 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 884                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 885 {
 886         uint8_t *odata;
 887         uint16_t otype, olen;
 888         uint32_t refresh = UINT32_MAX;
 889         int ret = 1;
 890         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 891
 892         odhcp6c_expire();
 893
 894         if (orig == DHCPV6_MSG_UNKNOWN) {
 895                 static time_t last_update = 0;
 896                 time_t now = odhcp6c_get_milli_time() / 1000;
 897
 898                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 899                 last_update = now;
 900
 901                 if (t1 != UINT32_MAX)
 902                         t1 -= elapsed;
 903
 904                 if (t2 != UINT32_MAX)
 905                         t2 -= elapsed;
 906
 907                 if (t3 != UINT32_MAX)
 908                         t3 -= elapsed;
 909
 910                 if (t1 < 0)
 911                         t1 = 0;
 912
 913                 if (t2 < 0)
 914                         t2 = 0;
 915
 916                 if (t3 < 0)
 917                         t3 = 0;
 918         }
 919
 920         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 921                 // Delete NA and PD we have in the state from the Advert
 922                 odhcp6c_clear_state(STATE_IA_NA);
 923                 odhcp6c_clear_state(STATE_IA_PD);
 924         }
 925
 926         if (opt) {
 927                 odhcp6c_clear_state(STATE_DNS);
 928                 odhcp6c_clear_state(STATE_SEARCH);
 929                 odhcp6c_clear_state(STATE_SNTP_IP);
 930                 odhcp6c_clear_state(STATE_NTP_IP);
 931                 odhcp6c_clear_state(STATE_NTP_FQDN);
 932                 odhcp6c_clear_state(STATE_SIP_IP);
 933                 odhcp6c_clear_state(STATE_SIP_FQDN);
 934                 odhcp6c_clear_state(STATE_AFTR_NAME);
 935                 odhcp6c_clear_state(STATE_CER);
 936                 odhcp6c_clear_state(STATE_S46_MAPT);
 937                 odhcp6c_clear_state(STATE_S46_MAPE);
 938                 odhcp6c_clear_state(STATE_S46_LW);
 939                 odhcp6c_clear_state(STATE_PASSTHRU);
 940         }
 941
 942         // Parse and find all matching IAs
 943         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 944                 bool passthru = true;
 945
 946                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 947                                 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 948                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 949
 950                         // Test ID
 951                         if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
 952                                 continue;
 953
 954                         uint16_t code = DHCPV6_Success;
 955                         uint16_t stype, slen;
 956                         uint8_t *sdata;
 957                         // Get and handle status code
 958                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 959                                         stype, slen, sdata) {
 960                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 961                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 962                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 963
 964                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 965
 966                                         if (code == DHCPV6_Success)
 967                                                 continue;
 968
 969                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 970                                                 code, mdata, mlen, handled_status_codes, &ret);
 971
 972
 973                                         if (ret > 0)
 974                                                 return ret;
 975                                         break;
 976                                 }
 977                         }
 978
 979                         if (code != DHCPV6_Success)
 980                                 continue;
 981
 982                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 983                         passthru = false;
 984                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 985                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 986                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 987                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 988
 989                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 990                         passthru = false;
 991                 }
 992                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 993                         if (olen % 16 == 0)
 994                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 995                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 996                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 997                         passthru = false;
 998                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 999                         if (olen % 16 == 0)
1000                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1001                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1002                         uint16_t stype, slen;
1003                         uint8_t *sdata;
1004                         // Test status and bail if error
1005                         dhcpv6_for_each_option(odata, odata + olen,
1006                                         stype, slen, sdata) {
1007                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
1008                                                 stype == NTP_SRV_ADDR))
1009                                         odhcp6c_add_state(STATE_NTP_IP,
1010                                                         sdata, slen);
1011                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
1012                                         odhcp6c_add_state(STATE_NTP_FQDN,
1013                                                         sdata, slen);
1014                         }
1015                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1016                         if (olen == 16)
1017                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1018                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1019                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1020                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1021                         refresh = ntohl(*((uint32_t*)odata));
1022                         passthru = false;
1023                 } else if (otype == DHCPV6_OPT_AUTH) {
1024                         if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1025                                 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1026                                 if (r->protocol == 3 && r->algorithm == 1 &&
1027                                                 r->reconf_type == 1)
1028                                         memcpy(reconf_key, r->key, sizeof(r->key));
1029                         }
1030                         passthru = false;
1031                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1032                         size_t cur_len;
1033                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1034                         if (cur_len == 0)
1035                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1036                         passthru = false;
1037                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1038                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1039                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1040                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1041                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1042                         passthru = false;
1043                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1044                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1045                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1046                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1047                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1048                         passthru = false;
1049 #ifdef EXT_CER_ID
1050                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1051                                 sizeof(struct dhcpv6_cer_id)) {
1052                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1053                         struct in6_addr any = IN6ADDR_ANY_INIT;
1054                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1055                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1056                         passthru = false;
1057 #endif
1058                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1059                         odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1060                         passthru = false;
1061                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1062                         size_t mape_len;
1063                         odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1064                         if (mape_len == 0)
1065                                 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1066                         passthru = false;
1067                 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1068                         odhcp6c_add_state(STATE_S46_LW, odata, olen);
1069                         passthru = false;
1070                 } else if (otype == DHCPV6_OPT_CLIENTID ||
1071                                 otype == DHCPV6_OPT_SERVERID ||
1072                                 otype == DHCPV6_OPT_IA_TA ||
1073                                 otype == DHCPV6_OPT_PREF ||
1074                                 otype == DHCPV6_OPT_UNICAST ||
1075                                 otype == DHCPV6_OPT_FQDN ||
1076                                 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1077                         passthru = false;
1078                 } else {
1079                         odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1080                 }
1081
1082                 if (passthru)
1083                         odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1084         }
1085
1086         if (orig != DHCPV6_MSG_INFO_REQ) {
1087                 // Update refresh timers if no fatal status code was received
1088                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1089                         switch (orig) {
1090                         case DHCPV6_MSG_RENEW:
1091                                 // Send further renews if T1 is not set
1092                                 if (!t1)
1093                                         ret = -1;
1094                                 break;
1095                         case DHCPV6_MSG_REBIND:
1096                                 // Send further rebinds if T1 and T2 is not set
1097                                 if (!t1 && !t2)
1098                                         ret = -1;
1099                                 break;
1100
1101                         case DHCPV6_MSG_REQUEST:
1102                                 // All server candidates can be cleared if not yet bound
1103                                 if (!odhcp6c_is_bound())
1104                                         dhcpv6_clear_all_server_cand();
1105
1106                         default :
1107                                 break;
1108                         }
1109
1110                         if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1111                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1112                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1113                         }
1114                 }
1115         }
1116         else if (ret > 0) {
1117                 // All server candidates can be cleared if not yet bound
1118                 if (!odhcp6c_is_bound())
1119                         dhcpv6_clear_all_server_cand();
1120
1121                 t1 = refresh;
1122         }
1123
1124         return ret;
1125 }
1126
1127
1128 static int dhcpv6_parse_ia(void *opt, void *end)
1129 {
1130         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1131         int parsed_ia = 0;
1132         uint32_t t1, t2;
1133         uint16_t otype, olen;
1134         uint8_t *odata;
1135
1136         t1 = ntohl(ia_hdr->t1);
1137         t2 = ntohl(ia_hdr->t2);
1138
1139         if (t1 > t2)
1140                 return 0;
1141
1142         // Update address IA
1143         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1144                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1145                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1146
1147                 entry.iaid = ia_hdr->iaid;
1148
1149                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1150                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1151                         if (olen + 4U < sizeof(*prefix))
1152                                 continue;
1153
1154                         entry.valid = ntohl(prefix->valid);
1155                         entry.preferred = ntohl(prefix->preferred);
1156
1157                         if (entry.preferred > entry.valid)
1158                                 continue;
1159
1160                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1161                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1162                         if (entry.t1 > entry.t2)
1163                                 entry.t1 = entry.t2;
1164
1165                         entry.length = prefix->prefix;
1166                         entry.target = prefix->addr;
1167                         uint16_t stype, slen;
1168                         uint8_t *sdata;
1169
1170 #ifdef EXT_PREFIX_CLASS
1171                         // Find prefix class, if any
1172                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1173                                         stype, slen, sdata)
1174                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1175                                         entry.class = sdata[0] << 8 | sdata[1];
1176 #endif
1177
1178                         // Parse PD-exclude
1179                         bool ok = true;
1180                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1181                                         odata + olen, stype, slen, sdata) {
1182                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1183                                         continue;
1184
1185                                 uint8_t elen = sdata[0];
1186                                 if (elen > 64)
1187                                         elen = 64;
1188
1189                                 if (elen <= 32 || elen <= entry.length) {
1190                                         ok = false;
1191                                         continue;
1192                                 }
1193
1194
1195                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1196                                 if (slen <= bytes) {
1197                                         ok = false;
1198                                         continue;
1199                                 }
1200
1201                                 uint32_t exclude = 0;
1202                                 do {
1203                                         exclude = exclude << 8 | sdata[bytes];
1204                                 } while (--bytes);
1205
1206                                 exclude >>= 8 - ((elen - entry.length) % 8);
1207                                 exclude <<= 64 - elen;
1208
1209                                 // Abusing router & priority fields for exclusion
1210                                 entry.router = entry.target;
1211                                 entry.router.s6_addr32[1] |= htonl(exclude);
1212                                 entry.priority = elen;
1213                         }
1214
1215                         if (ok) {
1216                                 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1217                                 parsed_ia++;
1218                         }
1219
1220                         entry.priority = 0;
1221                         memset(&entry.router, 0, sizeof(entry.router));
1222                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1223                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1224                         if (olen + 4U < sizeof(*addr))
1225                                 continue;
1226
1227                         entry.preferred = ntohl(addr->preferred);
1228                         entry.valid = ntohl(addr->valid);
1229
1230                         if (entry.preferred > entry.valid)
1231                                 continue;
1232
1233                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1234                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1235                         if (entry.t1 > entry.t2)
1236                                 entry.t1 = entry.t2;
1237
1238                         entry.length = 128;
1239                         entry.target = addr->addr;
1240
1241 #ifdef EXT_PREFIX_CLASS
1242                         uint16_t stype, slen;
1243                         uint8_t *sdata;
1244                         // Find prefix class, if any
1245                         dhcpv6_for_each_option(&addr[1], odata + olen,
1246                                         stype, slen, sdata)
1247                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1248                                         entry.class = sdata[0] << 8 | sdata[1];
1249 #endif
1250
1251                         odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
1252                         parsed_ia++;
1253                 }
1254         }
1255         return parsed_ia;
1256 }
1257
1258
1259 static int dhcpv6_calc_refresh_timers(void)
1260 {
1261         struct odhcp6c_entry *e;
1262         size_t ia_na_entries, ia_pd_entries, i;
1263         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1264
1265         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1266         ia_na_entries /= sizeof(*e);
1267         for (i = 0; i < ia_na_entries; i++) {
1268                 if (e[i].t1 < l_t1)
1269                         l_t1 = e[i].t1;
1270
1271                 if (e[i].t2 < l_t2)
1272                         l_t2 = e[i].t2;
1273
1274                 if (e[i].valid > l_t3)
1275                         l_t3 = e[i].valid;
1276         }
1277
1278         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1279         ia_pd_entries /= sizeof(*e);
1280         for (i = 0; i < ia_pd_entries; i++) {
1281                 if (e[i].t1 < l_t1)
1282                         l_t1 = e[i].t1;
1283
1284                 if (e[i].t2 < l_t2)
1285                         l_t2 = e[i].t2;
1286
1287                 if (e[i].valid > l_t3)
1288                         l_t3 = e[i].valid;
1289         }
1290
1291         if (ia_pd_entries || ia_na_entries) {
1292                 t1 = l_t1;
1293                 t2 = l_t2;
1294                 t3 = l_t3;
1295         } else {
1296                 t1 = 600;
1297         }
1298
1299         return (int)(ia_pd_entries + ia_na_entries);
1300 }
1301
1302
1303 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1304                 const void *status_msg, const int len)
1305 {
1306         uint8_t buf[len + 3];
1307
1308         memset(buf, 0, sizeof(buf));
1309         if (len) {
1310                 buf[0] = '(';
1311                 memcpy(&buf[1], status_msg, len);
1312                 buf[len + 1] = ')';
1313         }
1314
1315         syslog(LOG_WARNING, "Server returned %s status %i %s",
1316                 scope, code, buf);
1317 }
1318
1319
1320 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1321                 const uint16_t code, const void *status_msg, const int len,
1322                 int *ret)
1323 {
1324         dhcpv6_log_status_code(code, "message", status_msg, len);
1325
1326         switch (code) {
1327         case DHCPV6_UnspecFail:
1328                 // Generic failure
1329                 *ret = 0;
1330                 break;
1331
1332         case DHCPV6_UseMulticast:
1333                 // TODO handle multicast status code
1334                 break;
1335
1336         case DHCPV6_NoAddrsAvail:
1337         case DHCPV6_NoPrefixAvail:
1338                 if (orig == DHCPV6_MSG_REQUEST)
1339                         *ret = 0; // Failure
1340                 break;
1341
1342         default:
1343                 break;
1344         }
1345 }
1346
1347
1348 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1349                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1350                 const void *status_msg, const int len,
1351                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1352 {
1353         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1354                 "IA_NA" : "IA_PD", status_msg, len);
1355
1356         switch (code) {
1357         case DHCPV6_NoBinding:
1358                 switch (orig) {
1359                 case DHCPV6_MSG_RENEW:
1360                 case DHCPV6_MSG_REBIND:
1361                         if ((*ret > 0) && !handled_status_codes[code])
1362                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1363                         break;
1364
1365                 default:
1366                         break;
1367                 }
1368                 break;
1369
1370         default:
1371                 *ret = 0;
1372                 break;
1373         }
1374 }
1375
1376 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1377 {
1378         size_t cand_len, i;
1379         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1380
1381         // Remove identical duid server candidate
1382         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1383                 if (cand->duid_len == c[i].duid_len &&
1384                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1385                         free(c[i].ia_na);
1386                         free(c[i].ia_pd);
1387                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1388                         break;
1389                 }
1390         }
1391
1392         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1393                 i < cand_len / sizeof(*c); ++i) {
1394                 if (c[i].preference < cand->preference)
1395                         break;
1396         }
1397
1398         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1399 }
1400
1401 static void dhcpv6_clear_all_server_cand(void)
1402 {
1403         size_t cand_len, i;
1404         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1405
1406         // Server candidates need deep delete for IA_NA/IA_PD
1407         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1408                 free(c[i].ia_na);
1409                 free(c[i].ia_pd);
1410         }
1411         odhcp6c_clear_state(STATE_SERVER_CAND);
1412 }
1413
1414 int dhcpv6_promote_server_cand(void)
1415 {
1416         size_t cand_len;
1417         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1418         uint16_t hdr[2];
1419         int ret = DHCPV6_STATELESS;
1420
1421         // Clear lingering candidate state info
1422         odhcp6c_clear_state(STATE_SERVER_ID);
1423         odhcp6c_clear_state(STATE_IA_NA);
1424         odhcp6c_clear_state(STATE_IA_PD);
1425
1426         if (!cand_len)
1427                 return -1;
1428
1429         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1430                 na_mode = IA_MODE_NONE;
1431
1432                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1433                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1434
1435                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1436         }
1437
1438         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1439         hdr[1] = htons(cand->duid_len);
1440         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1441         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1442         accept_reconfig = cand->wants_reconfigure;
1443         if (cand->ia_na_len) {
1444                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1445                 free(cand->ia_na);
1446                 if (na_mode != IA_MODE_NONE)
1447                         ret = DHCPV6_STATEFUL;
1448         }
1449         if (cand->ia_pd_len) {
1450                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1451                 free(cand->ia_pd);
1452                 if (request_prefix)
1453                         ret = DHCPV6_STATEFUL;
1454         }
1455
1456         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1457         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1458
1459         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1460
1461         return ret;
1462 }