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                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 332                                 ia_pd_len += sizeof(p);
 333
 334                                 if (ex_len) {
 335                                         ia_pd[ia_pd_len++] = 0;
 336                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 337                                         ia_pd[ia_pd_len++] = 0;
 338                                         ia_pd[ia_pd_len++] = ex_len - 4;
 339                                         ia_pd[ia_pd_len++] = e[j].priority;
 340
 341                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 342                                         excl >>= (64 - e[j].priority);
 343                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 344
 345                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 346                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 347                                         ia_pd_len += ex_len - 5;
 348                                 }
 349
 350                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 351                         }
 352                 }
 353         }
 354
 355         if (ia_pd_entries > 0)
 356                 request_prefix = 1;
 357
 358         // Build IA_NAs
 359         size_t ia_na_entries, ia_na_len = 0;
 360         void *ia_na = NULL;
 361         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 362         ia_na_entries /= sizeof(*e);
 363
 364         struct dhcpv6_ia_hdr hdr_ia_na = {
 365                 htons(DHCPV6_OPT_IA_NA),
 366                 htons(sizeof(hdr_ia_na) - 4),
 367                 htonl(1), 0, 0
 368         };
 369
 370         struct dhcpv6_ia_addr pa[ia_na_entries];
 371         for (size_t i = 0; i < ia_na_entries; ++i) {
 372                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 373                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 374                 pa[i].addr = e[i].target;
 375                 pa[i].preferred = 0;
 376                 pa[i].valid = 0;
 377         }
 378
 379         ia_na = pa;
 380         ia_na_len = sizeof(pa);
 381         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 382
 383         // Reconfigure Accept
 384         struct {
 385                 uint16_t type;
 386                 uint16_t length;
 387         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 388
 389         // Request Information Refresh
 390         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 391
 392         // Build vendor-class option
 393         size_t vendor_class_len, user_class_len;
 394         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 395         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 396
 397         struct {
 398                 uint16_t type;
 399                 uint16_t length;
 400         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 401
 402         struct {
 403                 uint16_t type;
 404                 uint16_t length;
 405         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 406
 407         // Prepare Header
 408         size_t oro_len;
 409         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 410         struct {
 411                 uint8_t type;
 412                 uint8_t trid[3];
 413                 uint16_t elapsed_type;
 414                 uint16_t elapsed_len;
 415                 uint16_t elapsed_value;
 416                 uint16_t oro_type;
 417                 uint16_t oro_len;
 418         } hdr = {
 419                 type, {trid[0], trid[1], trid[2]},
 420                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 421                         htons((ecs > 0xffff) ? 0xffff : ecs),
 422                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 423         };
 424
 425         struct iovec iov[IOV_TOTAL] = {
 426                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 427                 [IOV_ORO] = {oro, oro_len},
 428                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 429                 [IOV_CL_ID] = {cl_id, cl_id_len},
 430                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 431                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 432                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 433                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 434                 [IOV_USER_CLASS] = {user_class, user_class_len},
 435                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 436                 [IOV_FQDN] = {&fqdn, fqdn_len},
 437                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 438                 [IOV_IA_NA] = {ia_na, ia_na_len},
 439                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 440         };
 441
 442         size_t cnt = IOV_TOTAL;
 443         if (type == DHCPV6_MSG_INFO_REQ) {
 444                 cnt = 9;
 445                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 446                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 447         } else if (!request_prefix) {
 448                 cnt = 13;
 449         }
 450
 451         // Disable IAs if not used
 452         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 453                 iov[IOV_HDR_IA_NA].iov_len = 0;
 454
 455         if (na_mode == IA_MODE_NONE)
 456                 iov[IOV_HDR_IA_NA].iov_len = 0;
 457
 458         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 459                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 460                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 461
 462         if (!(client_options & DHCPV6_CLIENT_FQDN))
 463                 iov[IOV_FQDN].iov_len = 0;
 464
 465         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 466                 0, ALL_DHCPV6_RELAYS, ifindex};
 467         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 468                         .msg_iov = iov, .msg_iovlen = cnt};
 469
 470         sendmsg(sock, &msg, 0);
 471 }
 472
 473
 474 static int64_t dhcpv6_rand_delay(int64_t time)
 475 {
 476         int random;
 477         odhcp6c_random(&random, sizeof(random));
 478         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 479 }
 480
 481
 482 int dhcpv6_request(enum dhcpv6_msg type)
 483 {
 484         uint8_t rc = 0;
 485         uint64_t timeout = UINT32_MAX;
 486         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 487
 488         if (retx->delay) {
 489                 struct timespec ts = {0, 0};
 490                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 491                 nanosleep(&ts, NULL);
 492         }
 493
 494         if (type == DHCPV6_MSG_UNKNOWN)
 495                 timeout = t1;
 496         else if (type == DHCPV6_MSG_RENEW)
 497                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 498         else if (type == DHCPV6_MSG_REBIND)
 499                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 500
 501         if (timeout == 0)
 502                 return -1;
 503
 504         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 505                         retx->name, (unsigned long long)timeout, retx->max_rc);
 506
 507         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 508
 509         // Generate transaction ID
 510         uint8_t trid[3] = {0, 0, 0};
 511         if (type != DHCPV6_MSG_UNKNOWN)
 512                 odhcp6c_random(trid, sizeof(trid));
 513         ssize_t len = -1;
 514         int64_t rto = 0;
 515
 516         do {
 517                 if (rto == 0) {
 518                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 519
 520                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 521                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 522                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 523
 524                         rto = (retx->init_timeo * 1000 + delay);
 525                 }
 526                 else
 527                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 528
 529                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 530                         rto = retx->max_timeo * 1000 +
 531                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 532
 533                 // Calculate end for this round and elapsed time
 534                 uint64_t round_end = round_start + rto;
 535                 elapsed = round_start - start;
 536
 537                 // Don't wait too long if timeout differs from infinite
 538                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 539                         round_end = timeout * 1000 + start;
 540
 541                 // Built and send package
 542                 if (type != DHCPV6_MSG_UNKNOWN) {
 543                         if (type != DHCPV6_MSG_SOLICIT)
 544                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 545                                                 retx->name, (unsigned long long)elapsed, rc);
 546                         dhcpv6_send(type, trid, elapsed / 10);
 547                         rc++;
 548                 }
 549
 550                 // Receive rounds
 551                 for (; len < 0 && (round_start < round_end);
 552                                 round_start = odhcp6c_get_milli_time()) {
 553                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 554                         struct iovec iov = {buf, sizeof(buf)};
 555                         struct sockaddr_in6 addr;
 556                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 557                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
 558                                         .msg_controllen = sizeof(cmsg_buf)};
 559                         struct in6_pktinfo *pktinfo = NULL;
 560
 561
 562                         // Check for pending signal
 563                         if (odhcp6c_signal_process())
 564                                 return -1;
 565
 566                         // Set timeout for receiving
 567                         uint64_t t = round_end - round_start;
 568                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 569                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 570                                         &tv, sizeof(tv));
 571
 572                         // Receive cycle
 573                         len = recvmsg(sock, &msg, 0);
 574                         if (len < 0)
 575                                 continue;
 576
 577                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 578                                 ch = CMSG_NXTHDR(&msg, ch)) {
 579                                 if (ch->cmsg_level == SOL_IPV6 &&
 580                                         ch->cmsg_type == IPV6_PKTINFO) {
 581                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 582                                         break;
 583                                 }
 584                         }
 585
 586                         if (pktinfo == NULL) {
 587                                 len = -1;
 588                                 continue;
 589                         }
 590
 591                         if (!dhcpv6_response_is_valid(buf, len, trid,
 592                                                         type, &pktinfo->ipi6_addr)) {
 593                                 len = -1;
 594                                 continue;
 595                         }
 596
 597                         uint8_t *opt = &buf[4];
 598                         uint8_t *opt_end = opt + len - 4;
 599
 600                         round_start = odhcp6c_get_milli_time();
 601                         elapsed = round_start - start;
 602                         syslog(LOG_NOTICE, "Got a valid reply after "
 603                                         "%llums", (unsigned long long)elapsed);
 604
 605                         if (retx->handler_reply)
 606                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 607
 608                         if (len > 0 && round_end - round_start > 1000)
 609                                 round_end = 1000 + round_start;
 610                 }
 611
 612                 // Allow
 613                 if (retx->handler_finish)
 614                         len = retx->handler_finish();
 615         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 616                         (!retx->max_rc || rc < retx->max_rc));
 617         return len;
 618 }
 619
 620 // Message validation checks according to RFC3315 chapter 15
 621 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 622                 const uint8_t transaction[3], enum dhcpv6_msg type,
 623                 const struct in6_addr *daddr)
 624 {
 625         const struct dhcpv6_header *rep = buf;
 626         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 627                         transaction, sizeof(rep->tr_id)))
 628                 return false; // Invalid reply
 629
 630         if (type == DHCPV6_MSG_SOLICIT) {
 631                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 632                                 rep->msg_type != DHCPV6_MSG_REPLY)
 633                         return false;
 634         } else if (type == DHCPV6_MSG_UNKNOWN) {
 635                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 636                         return false;
 637         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 638                 return false;
 639         }
 640
 641         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 642                 rcmsg = DHCPV6_MSG_UNKNOWN;
 643         uint16_t otype, olen = UINT16_MAX;
 644         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 645                 ia_present = false, options_valid = true;
 646
 647         size_t client_id_len, server_id_len;
 648         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 649         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 650
 651         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 652                 if (otype == DHCPV6_OPT_CLIENTID) {
 653                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 654                                         &odata[-4], client_id, client_id_len);
 655                 } else if (otype == DHCPV6_OPT_SERVERID) {
 656                         if (server_id_len)
 657                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 658                                                 &odata[-4], server_id, server_id_len);
 659                         else
 660                                 serverid_ok = true;
 661                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 662                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 663                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 664                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 665                                 continue;
 666
 667                         md5_ctx_t md5;
 668                         uint8_t serverhash[16], secretbytes[64], hash[16];
 669                         memcpy(serverhash, r->key, sizeof(serverhash));
 670                         memset(r->key, 0, sizeof(r->key));
 671
 672                         memset(secretbytes, 0, sizeof(secretbytes));
 673                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 674
 675                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 676                                 secretbytes[i] ^= 0x36;
 677
 678                         md5_begin(&md5);
 679                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 680                         md5_hash(buf, len, &md5);
 681                         md5_end(hash, &md5);
 682
 683                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 684                                 secretbytes[i] ^= 0x36;
 685                                 secretbytes[i] ^= 0x5c;
 686                         }
 687
 688                         md5_begin(&md5);
 689                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 690                         md5_hash(hash, 16, &md5);
 691                         md5_end(hash, &md5);
 692
 693                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 694                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 695                         rcmsg = odata[0];
 696                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 697                         ia_present = true;
 698                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 699                                 options_valid = false;
 700                 }
 701                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 702                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 703                         // Options are not allowed on global level
 704                         options_valid = false;
 705                 }
 706         }
 707
 708         if (!options_valid || ((odata + olen) > end))
 709                 return false;
 710
 711         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 712                 return false;
 713
 714         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 715                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 716                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 717                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 718                         return false;
 719         }
 720
 721         return clientid_ok && serverid_ok;
 722 }
 723
 724
 725 int dhcpv6_poll_reconfigure(void)
 726 {
 727         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 728         if (ret != -1)
 729                 ret = dhcpv6_request(ret);
 730
 731         return ret;
 732 }
 733
 734
 735 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 736                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 737 {
 738         uint16_t otype, olen;
 739         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 740         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 741                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 742                                 odata[0] == DHCPV6_MSG_RENEW ||
 743                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 744                         msg = odata[0];
 745
 746         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 747         return msg;
 748 }
 749
 750
 751 // Collect all advertised servers
 752 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 753                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 754 {
 755         uint16_t olen, otype;
 756         uint8_t *odata, pref = 0;
 757         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 758                                         DHCPV6_SOL_MAX_RT,
 759                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 760         bool have_na = false;
 761         int have_pd = 0;
 762
 763         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 764                 if (orig == DHCPV6_MSG_SOLICIT &&
 765                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 766                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 767                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 768                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 769                 }
 770
 771                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 772                         memcpy(cand.duid, odata, olen);
 773                         cand.duid_len = olen;
 774                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 775                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 776
 777                         switch (error) {
 778                         case DHCPV6_NoPrefixAvail:
 779                                 // Status code on global level
 780                                 cand.preference -= 2000;
 781                                 break;
 782
 783                         default :
 784                                 break;
 785                         }
 786                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 787                                 cand.preference >= 0) {
 788                         cand.preference = pref = odata[0];
 789                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 790                         cand.wants_reconfigure = true;
 791                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 792                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 793                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 794                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 795                                 cand.sol_max_rt = sol_max_rt;
 796                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 797                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 798                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 799                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 800                                 cand.inf_max_rt = inf_max_rt;
 801                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 802                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 803                         uint8_t *oend = odata + olen, *d;
 804                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 805                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 806                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 807                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 808                                         have_pd = p->prefix;
 809                                 }
 810                         }
 811                 } else if (otype == DHCPV6_OPT_IA_NA) {
 812                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 813                         uint8_t *oend = odata + olen, *d;
 814                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 815                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 816                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 817                                         have_na = true;
 818                 }
 819         }
 820
 821         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 822                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 823                 /*
 824                  * RFC7083 states to process the SOL_MAX_RT and
 825                  * INF_MAX_RT options even if the DHCPv6 server
 826                  * did not propose any IA_NA and/or IA_PD
 827                  */
 828                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 829                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 830                 return -1;
 831         }
 832
 833         if (na_mode != IA_MODE_NONE && !have_na) {
 834                 cand.has_noaddravail = true;
 835                 cand.preference -= 1000;
 836         }
 837
 838         if (pd_mode != IA_MODE_NONE) {
 839                 if (have_pd)
 840                         cand.preference += 2000 + (128 - have_pd);
 841                 else
 842                         cand.preference -= 2000;
 843         }
 844
 845         if (cand.duid_len > 0) {
 846                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 847                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 848                 dhcpv6_add_server_cand(&cand);
 849         }
 850
 851         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 852 }
 853
 854
 855 static int dhcpv6_commit_advert(void)
 856 {
 857         return dhcpv6_promote_server_cand();
 858 }
 859
 860
 861 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 862                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 863 {
 864         dhcpv6_handle_advert(orig, rc, opt, end, from);
 865         if (dhcpv6_commit_advert() < 0)
 866                 return -1;
 867
 868         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 869 }
 870
 871
 872 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 873                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 874 {
 875         uint8_t *odata;
 876         uint16_t otype, olen;
 877         uint32_t refresh = UINT32_MAX;
 878         int ret = 1;
 879         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 880
 881         odhcp6c_expire();
 882
 883         if (orig == DHCPV6_MSG_UNKNOWN) {
 884                 static time_t last_update = 0;
 885                 time_t now = odhcp6c_get_milli_time() / 1000;
 886
 887                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 888                 last_update = now;
 889
 890                 if (t1 != UINT32_MAX)
 891                         t1 -= elapsed;
 892
 893                 if (t2 != UINT32_MAX)
 894                         t2 -= elapsed;
 895
 896                 if (t3 != UINT32_MAX)
 897                         t3 -= elapsed;
 898
 899                 if (t1 < 0)
 900                         t1 = 0;
 901
 902                 if (t2 < 0)
 903                         t2 = 0;
 904
 905                 if (t3 < 0)
 906                         t3 = 0;
 907         }
 908
 909         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 910                 // Delete NA and PD we have in the state from the Advert
 911                 odhcp6c_clear_state(STATE_IA_NA);
 912                 odhcp6c_clear_state(STATE_IA_PD);
 913         }
 914
 915         if (opt) {
 916                 odhcp6c_clear_state(STATE_DNS);
 917                 odhcp6c_clear_state(STATE_SEARCH);
 918                 odhcp6c_clear_state(STATE_SNTP_IP);
 919                 odhcp6c_clear_state(STATE_NTP_IP);
 920                 odhcp6c_clear_state(STATE_NTP_FQDN);
 921                 odhcp6c_clear_state(STATE_SIP_IP);
 922                 odhcp6c_clear_state(STATE_SIP_FQDN);
 923                 odhcp6c_clear_state(STATE_AFTR_NAME);
 924                 odhcp6c_clear_state(STATE_CER);
 925                 odhcp6c_clear_state(STATE_S46_MAPT);
 926                 odhcp6c_clear_state(STATE_S46_MAPE);
 927                 odhcp6c_clear_state(STATE_S46_LW);
 928                 odhcp6c_clear_state(STATE_PASSTHRU);
 929         }
 930
 931         // Parse and find all matching IAs
 932         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 933                 bool passthru = true;
 934
 935                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 936                                 && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 937                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 938
 939                         // Test ID
 940                         if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
 941                                 continue;
 942
 943                         uint16_t code = DHCPV6_Success;
 944                         uint16_t stype, slen;
 945                         uint8_t *sdata;
 946                         // Get and handle status code
 947                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 948                                         stype, slen, sdata) {
 949                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 950                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 951                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 952
 953                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 954
 955                                         if (code == DHCPV6_Success)
 956                                                 continue;
 957
 958                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 959                                                 code, mdata, mlen, handled_status_codes, &ret);
 960
 961
 962                                         if (ret > 0)
 963                                                 return ret;
 964                                         break;
 965                                 }
 966                         }
 967
 968                         if (code != DHCPV6_Success)
 969                                 continue;
 970
 971                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 972                         passthru = false;
 973                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 974                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 975                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 976                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 977
 978                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 979                         passthru = false;
 980                 }
 981                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 982                         if (olen % 16 == 0)
 983                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 984                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 985                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 986                         passthru = false;
 987                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 988                         if (olen % 16 == 0)
 989                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 990                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 991                         uint16_t stype, slen;
 992                         uint8_t *sdata;
 993                         // Test status and bail if error
 994                         dhcpv6_for_each_option(odata, odata + olen,
 995                                         stype, slen, sdata) {
 996                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 997                                                 stype == NTP_SRV_ADDR))
 998                                         odhcp6c_add_state(STATE_NTP_IP,
 999                                                         sdata, slen);
1000                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
1001                                         odhcp6c_add_state(STATE_NTP_FQDN,
1002                                                         sdata, slen);
1003                         }
1004                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1005                         if (olen == 16)
1006                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1007                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1008                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1009                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1010                         refresh = ntohl(*((uint32_t*)odata));
1011                         passthru = false;
1012                 } else if (otype == DHCPV6_OPT_AUTH) {
1013                         if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1014                                 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1015                                 if (r->protocol == 3 && r->algorithm == 1 &&
1016                                                 r->reconf_type == 1)
1017                                         memcpy(reconf_key, r->key, sizeof(r->key));
1018                         }
1019                         passthru = false;
1020                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1021                         size_t cur_len;
1022                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1023                         if (cur_len == 0)
1024                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1025                         passthru = false;
1026                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1027                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1028                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1029                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1030                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1031                         passthru = false;
1032                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1033                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1034                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1035                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1036                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1037                         passthru = false;
1038 #ifdef EXT_CER_ID
1039                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1040                                 sizeof(struct dhcpv6_cer_id)) {
1041                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1042                         struct in6_addr any = IN6ADDR_ANY_INIT;
1043                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1044                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1045                         passthru = false;
1046 #endif
1047                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1048                         odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1049                         passthru = false;
1050                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1051                         size_t mape_len;
1052                         odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1053                         if (mape_len == 0)
1054                                 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1055                         passthru = false;
1056                 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1057                         odhcp6c_add_state(STATE_S46_LW, odata, olen);
1058                         passthru = false;
1059                 } else if (otype == DHCPV6_OPT_CLIENTID ||
1060                                 otype == DHCPV6_OPT_SERVERID ||
1061                                 otype == DHCPV6_OPT_IA_TA ||
1062                                 otype == DHCPV6_OPT_PREF ||
1063                                 otype == DHCPV6_OPT_UNICAST ||
1064                                 otype == DHCPV6_OPT_FQDN ||
1065                                 otype == DHCPV6_OPT_RECONF_ACCEPT) {
1066                         passthru = false;
1067                 } else {
1068                         odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1069                 }
1070
1071                 if (passthru)
1072                         odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1073         }
1074
1075         if (orig != DHCPV6_MSG_INFO_REQ) {
1076                 // Update refresh timers if no fatal status code was received
1077                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1078                         switch (orig) {
1079                         case DHCPV6_MSG_RENEW:
1080                                 // Send further renews if T1 is not set
1081                                 if (!t1)
1082                                         ret = -1;
1083                                 break;
1084                         case DHCPV6_MSG_REBIND:
1085                                 // Send further rebinds if T1 and T2 is not set
1086                                 if (!t1 && !t2)
1087                                         ret = -1;
1088                                 break;
1089
1090                         case DHCPV6_MSG_REQUEST:
1091                                 // All server candidates can be cleared if not yet bound
1092                                 if (!odhcp6c_is_bound())
1093                                         dhcpv6_clear_all_server_cand();
1094
1095                         default :
1096                                 break;
1097                         }
1098
1099                         if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1100                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1101                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1102                         }
1103                 }
1104         }
1105         else if (ret > 0) {
1106                 // All server candidates can be cleared if not yet bound
1107                 if (!odhcp6c_is_bound())
1108                         dhcpv6_clear_all_server_cand();
1109
1110                 t1 = refresh;
1111         }
1112
1113         return ret;
1114 }
1115
1116
1117 static int dhcpv6_parse_ia(void *opt, void *end)
1118 {
1119         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1120         int parsed_ia = 0;
1121         uint32_t t1, t2;
1122         uint16_t otype, olen;
1123         uint8_t *odata;
1124
1125         t1 = ntohl(ia_hdr->t1);
1126         t2 = ntohl(ia_hdr->t2);
1127
1128         if (t1 > t2)
1129                 return 0;
1130
1131         // Update address IA
1132         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1133                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1134                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1135
1136                 entry.iaid = ia_hdr->iaid;
1137
1138                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1139                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1140                         if (olen + 4U < sizeof(*prefix))
1141                                 continue;
1142
1143                         entry.valid = ntohl(prefix->valid);
1144                         entry.preferred = ntohl(prefix->preferred);
1145
1146                         if (entry.preferred > entry.valid)
1147                                 continue;
1148
1149                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1150                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1151                         if (entry.t1 > entry.t2)
1152                                 entry.t1 = entry.t2;
1153
1154                         entry.length = prefix->prefix;
1155                         entry.target = prefix->addr;
1156                         uint16_t stype, slen;
1157                         uint8_t *sdata;
1158
1159 #ifdef EXT_PREFIX_CLASS
1160                         // Find prefix class, if any
1161                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1162                                         stype, slen, sdata)
1163                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1164                                         entry.class = sdata[0] << 8 | sdata[1];
1165 #endif
1166
1167                         // Parse PD-exclude
1168                         bool ok = true;
1169                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1170                                         odata + olen, stype, slen, sdata) {
1171                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1172                                         continue;
1173
1174                                 uint8_t elen = sdata[0];
1175                                 if (elen > 64)
1176                                         elen = 64;
1177
1178                                 if (elen <= 32 || elen <= entry.length) {
1179                                         ok = false;
1180                                         continue;
1181                                 }
1182
1183
1184                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1185                                 if (slen <= bytes) {
1186                                         ok = false;
1187                                         continue;
1188                                 }
1189
1190                                 uint32_t exclude = 0;
1191                                 do {
1192                                         exclude = exclude << 8 | sdata[bytes];
1193                                 } while (--bytes);
1194
1195                                 exclude >>= 8 - ((elen - entry.length) % 8);
1196                                 exclude <<= 64 - elen;
1197
1198                                 // Abusing router & priority fields for exclusion
1199                                 entry.router = entry.target;
1200                                 entry.router.s6_addr32[1] |= htonl(exclude);
1201                                 entry.priority = elen;
1202                         }
1203
1204                         if (ok) {
1205                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1206                                 parsed_ia++;
1207                         }
1208
1209                         entry.priority = 0;
1210                         memset(&entry.router, 0, sizeof(entry.router));
1211                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1212                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1213                         if (olen + 4U < sizeof(*addr))
1214                                 continue;
1215
1216                         entry.preferred = ntohl(addr->preferred);
1217                         entry.valid = ntohl(addr->valid);
1218
1219                         if (entry.preferred > entry.valid)
1220                                 continue;
1221
1222                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1223                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1224                         if (entry.t1 > entry.t2)
1225                                 entry.t1 = entry.t2;
1226
1227                         entry.length = 128;
1228                         entry.target = addr->addr;
1229
1230 #ifdef EXT_PREFIX_CLASS
1231                         uint16_t stype, slen;
1232                         uint8_t *sdata;
1233                         // Find prefix class, if any
1234                         dhcpv6_for_each_option(&addr[1], odata + olen,
1235                                         stype, slen, sdata)
1236                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1237                                         entry.class = sdata[0] << 8 | sdata[1];
1238 #endif
1239
1240                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1241                         parsed_ia++;
1242                 }
1243         }
1244         return parsed_ia;
1245 }
1246
1247
1248 static int dhcpv6_calc_refresh_timers(void)
1249 {
1250         struct odhcp6c_entry *e;
1251         size_t ia_na_entries, ia_pd_entries, i;
1252         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1253
1254         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1255         ia_na_entries /= sizeof(*e);
1256         for (i = 0; i < ia_na_entries; i++) {
1257                 if (e[i].t1 < l_t1)
1258                         l_t1 = e[i].t1;
1259
1260                 if (e[i].t2 < l_t2)
1261                         l_t2 = e[i].t2;
1262
1263                 if (e[i].valid > l_t3)
1264                         l_t3 = e[i].valid;
1265         }
1266
1267         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1268         ia_pd_entries /= sizeof(*e);
1269         for (i = 0; i < ia_pd_entries; i++) {
1270                 if (e[i].t1 < l_t1)
1271                         l_t1 = e[i].t1;
1272
1273                 if (e[i].t2 < l_t2)
1274                         l_t2 = e[i].t2;
1275
1276                 if (e[i].valid > l_t3)
1277                         l_t3 = e[i].valid;
1278         }
1279
1280         if (ia_pd_entries || ia_na_entries) {
1281                 t1 = l_t1;
1282                 t2 = l_t2;
1283                 t3 = l_t3;
1284         } else {
1285                 t1 = 600;
1286         }
1287
1288         return (int)(ia_pd_entries + ia_na_entries);
1289 }
1290
1291
1292 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1293                 const void *status_msg, const int len)
1294 {
1295         uint8_t buf[len + 3];
1296
1297         memset(buf, 0, sizeof(buf));
1298         if (len) {
1299                 buf[0] = '(';
1300                 memcpy(&buf[1], status_msg, len);
1301                 buf[len + 1] = ')';
1302         }
1303
1304         syslog(LOG_WARNING, "Server returned %s status %i %s",
1305                 scope, code, buf);
1306 }
1307
1308
1309 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1310                 const uint16_t code, const void *status_msg, const int len,
1311                 int *ret)
1312 {
1313         dhcpv6_log_status_code(code, "message", status_msg, len);
1314
1315         switch (code) {
1316         case DHCPV6_UnspecFail:
1317                 // Generic failure
1318                 *ret = 0;
1319                 break;
1320
1321         case DHCPV6_UseMulticast:
1322                 // TODO handle multicast status code
1323                 break;
1324
1325         case DHCPV6_NoAddrsAvail:
1326         case DHCPV6_NoPrefixAvail:
1327                 if (orig == DHCPV6_MSG_REQUEST)
1328                         *ret = 0; // Failure
1329                 break;
1330
1331         default:
1332                 break;
1333         }
1334 }
1335
1336
1337 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1338                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1339                 const void *status_msg, const int len,
1340                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1341 {
1342         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1343                 "IA_NA" : "IA_PD", status_msg, len);
1344
1345         switch (code) {
1346         case DHCPV6_NoBinding:
1347                 switch (orig) {
1348                 case DHCPV6_MSG_RENEW:
1349                 case DHCPV6_MSG_REBIND:
1350                         if ((*ret > 0) && !handled_status_codes[code])
1351                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1352                         break;
1353
1354                 default:
1355                         break;
1356                 }
1357                 break;
1358
1359         case DHCPV6_NoAddrsAvail:
1360         case DHCPV6_NoPrefixAvail:
1361                 switch (orig) {
1362                 case DHCPV6_MSG_REQUEST:
1363                         if (*ret != 0)
1364                                 *ret = 0;
1365                         break;
1366                 default:
1367                         break;
1368                 }
1369                 break;
1370
1371         case DHCPV6_NotOnLink:
1372                 // TODO handle not onlink in case of confirm
1373                 break;
1374
1375         default:
1376                 break;
1377         }
1378 }
1379
1380 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1381 {
1382         size_t cand_len, i;
1383         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1384
1385         // Remove identical duid server candidate
1386         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1387                 if (cand->duid_len == c[i].duid_len &&
1388                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1389                         free(c[i].ia_na);
1390                         free(c[i].ia_pd);
1391                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1392                         break;
1393                 }
1394         }
1395
1396         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1397                 i < cand_len / sizeof(*c); ++i) {
1398                 if (c[i].preference < cand->preference)
1399                         break;
1400         }
1401
1402         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1403 }
1404
1405 static void dhcpv6_clear_all_server_cand(void)
1406 {
1407         size_t cand_len, i;
1408         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1409
1410         // Server candidates need deep delete for IA_NA/IA_PD
1411         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1412                 free(c[i].ia_na);
1413                 free(c[i].ia_pd);
1414         }
1415         odhcp6c_clear_state(STATE_SERVER_CAND);
1416 }
1417
1418 int dhcpv6_promote_server_cand(void)
1419 {
1420         size_t cand_len;
1421         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1422         uint16_t hdr[2];
1423         int ret = DHCPV6_STATELESS;
1424
1425         // Clear lingering candidate state info
1426         odhcp6c_clear_state(STATE_SERVER_ID);
1427         odhcp6c_clear_state(STATE_IA_NA);
1428         odhcp6c_clear_state(STATE_IA_PD);
1429
1430         if (!cand_len)
1431                 return -1;
1432
1433         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1434                 na_mode = IA_MODE_NONE;
1435
1436                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1437                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1438
1439                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1440         }
1441
1442         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1443         hdr[1] = htons(cand->duid_len);
1444         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1445         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1446         accept_reconfig = cand->wants_reconfigure;
1447         if (cand->ia_na_len) {
1448                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1449                 free(cand->ia_na);
1450                 if (na_mode != IA_MODE_NONE)
1451                         ret = DHCPV6_STATEFUL;
1452         }
1453         if (cand->ia_pd_len) {
1454                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1455                 free(cand->ia_pd);
1456                 if (request_prefix)
1457                         ret = DHCPV6_STATEFUL;
1458         }
1459
1460         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1461         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1462
1463         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1464
1465         return ret;
1466 }