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_CER_ID
 177                         htons(DHCPV6_OPT_CER_ID),
 178 #endif
 179                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 180                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 181                         htons(DHCPV6_OPT_S46_CONT_LW),
 182                 };
 183                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 184         }
 185
 186         // Configure IPv6-options
 187         int val = 1;
 188         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 189         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 190         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 191         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 192
 193         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 194                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 195         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 196                 return -1;
 197
 198         return 0;
 199 }
 200
 201 enum {
 202         IOV_HDR=0,
 203         IOV_ORO,
 204         IOV_ORO_REFRESH,
 205         IOV_CL_ID,
 206         IOV_SRV_ID,
 207         IOV_VENDOR_CLASS_HDR,
 208         IOV_VENDOR_CLASS,
 209         IOV_USER_CLASS_HDR,
 210         IOV_USER_CLASS,
 211         IOV_RECONF_ACCEPT,
 212         IOV_FQDN,
 213         IOV_HDR_IA_NA,
 214         IOV_IA_NA,
 215         IOV_IA_PD,
 216         IOV_TOTAL
 217 };
 218
 219 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 220 {
 221         int mode = DHCPV6_UNKNOWN;
 222
 223         na_mode = na;
 224         pd_mode = pd;
 225
 226         if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
 227                 mode = DHCPV6_STATELESS;
 228         else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
 229                 mode = DHCPV6_STATEFUL;
 230
 231         return mode;
 232 }
 233
 234 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 235 {
 236         // Build FQDN
 237         char fqdn_buf[256];
 238         gethostname(fqdn_buf, sizeof(fqdn_buf));
 239         struct {
 240                 uint16_t type;
 241                 uint16_t len;
 242                 uint8_t flags;
 243                 uint8_t data[256];
 244         } fqdn;
 245         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 246                         sizeof(fqdn.data), NULL, NULL);
 247         fqdn.type = htons(DHCPV6_OPT_FQDN);
 248         fqdn.len = htons(fqdn_len - 4);
 249         fqdn.flags = 0;
 250
 251
 252         // Build Client ID
 253         size_t cl_id_len;
 254         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 255
 256         // Get Server ID
 257         size_t srv_id_len;
 258         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 259
 260         // Build IA_PDs
 261         size_t ia_pd_entries = 0, ia_pd_len = 0;
 262         uint8_t *ia_pd;
 263
 264         if (type == DHCPV6_MSG_SOLICIT) {
 265                 odhcp6c_clear_state(STATE_IA_PD);
 266                 size_t n_prefixes;
 267                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 268                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 269
 270                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 271
 272                 for (size_t i = 0; i < n_prefixes; i++) {
 273                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 274                                 htons(DHCPV6_OPT_IA_PD),
 275                                 htons(sizeof(hdr_ia_pd) - 4 +
 276                                       sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
 277                                 request_prefixes[i].iaid, 0, 0
 278                         };
 279                         struct dhcpv6_ia_prefix pref = {
 280                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 281                                 .len = htons(sizeof(pref) - 4),
 282                                 .prefix = request_prefixes[i].length
 283                         };
 284                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 285                         ia_pd_len += sizeof(hdr_ia_pd);
 286                         if (request_prefixes[i].length) {
 287                                 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 288                                 ia_pd_len += sizeof(pref);
 289                         }
 290                 }
 291         } else {
 292                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 293                 ia_pd_entries /= sizeof(*e);
 294
 295                 // we're too lazy to count our distinct IAIDs,
 296                 // so just allocate maximally needed space
 297                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 298                                         sizeof(struct dhcpv6_ia_hdr)));
 299
 300                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 301                         uint32_t iaid = e[i].iaid;
 302
 303                         // check if this is an unprocessed IAID and skip if not.
 304                         int new_iaid = 1;
 305                         for (int j = i-1; j >= 0; j--) {
 306                                 if (e[j].iaid == iaid) {
 307                                         new_iaid = 0;
 308                                         break;
 309                                 }
 310                         }
 311
 312                         if (!new_iaid)
 313                                 continue;
 314
 315                         // construct header
 316                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 317                                 htons(DHCPV6_OPT_IA_PD),
 318                                 htons(sizeof(hdr_ia_pd) - 4),
 319                                 iaid, 0, 0
 320                         };
 321
 322                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 323                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 324                         ia_pd_len += sizeof(hdr_ia_pd);
 325
 326                         for (size_t j = i; j < ia_pd_entries; j++) {
 327                                 if (e[j].iaid != iaid)
 328                                         continue;
 329
 330                                 uint8_t ex_len = 0;
 331                                 if (e[j].priority > 0)
 332                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 333
 334                                 struct dhcpv6_ia_prefix p = {
 335                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 336                                         .len = htons(sizeof(p) - 4U + ex_len),
 337                                         .prefix = e[j].length,
 338                                         .addr = e[j].target
 339                                 };
 340
 341                                 if (type == DHCPV6_MSG_REQUEST) {
 342                                         p.preferred = htonl(e[j].preferred);
 343                                         p.valid = htonl(e[j].valid);
 344                                 }
 345
 346                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 347                                 ia_pd_len += sizeof(p);
 348
 349                                 if (ex_len) {
 350                                         ia_pd[ia_pd_len++] = 0;
 351                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 352                                         ia_pd[ia_pd_len++] = 0;
 353                                         ia_pd[ia_pd_len++] = ex_len - 4;
 354                                         ia_pd[ia_pd_len++] = e[j].priority;
 355
 356                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 357                                         excl >>= (64 - e[j].priority);
 358                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 359
 360                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 361                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 362                                         ia_pd_len += ex_len - 5;
 363                                 }
 364
 365                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 366                         }
 367                 }
 368         }
 369
 370         if (ia_pd_entries > 0)
 371                 request_prefix = 1;
 372
 373         // Build IA_NAs
 374         size_t ia_na_entries, ia_na_len = 0;
 375         void *ia_na = NULL;
 376         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 377         ia_na_entries /= sizeof(*e);
 378
 379         struct dhcpv6_ia_hdr hdr_ia_na = {
 380                 htons(DHCPV6_OPT_IA_NA),
 381                 htons(sizeof(hdr_ia_na) - 4),
 382                 htonl(1), 0, 0
 383         };
 384
 385         struct dhcpv6_ia_addr pa[ia_na_entries];
 386         for (size_t i = 0; i < ia_na_entries; ++i) {
 387                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 388                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 389                 pa[i].addr = e[i].target;
 390
 391                 if (type == DHCPV6_MSG_REQUEST) {
 392                         pa[i].preferred = htonl(e[i].preferred);
 393                         pa[i].valid = htonl(e[i].valid);
 394                 } else {
 395                         pa[i].preferred = 0;
 396                         pa[i].valid = 0;
 397                 }
 398         }
 399
 400         ia_na = pa;
 401         ia_na_len = sizeof(pa);
 402         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 403
 404         // Reconfigure Accept
 405         struct {
 406                 uint16_t type;
 407                 uint16_t length;
 408         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 409
 410         // Request Information Refresh
 411         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 412
 413         // Build vendor-class option
 414         size_t vendor_class_len, user_class_len;
 415         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 416         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 417
 418         struct {
 419                 uint16_t type;
 420                 uint16_t length;
 421         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 422
 423         struct {
 424                 uint16_t type;
 425                 uint16_t length;
 426         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 427
 428         // Prepare Header
 429         size_t oro_len;
 430         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 431         struct {
 432                 uint8_t type;
 433                 uint8_t trid[3];
 434                 uint16_t elapsed_type;
 435                 uint16_t elapsed_len;
 436                 uint16_t elapsed_value;
 437                 uint16_t oro_type;
 438                 uint16_t oro_len;
 439         } hdr = {
 440                 type, {trid[0], trid[1], trid[2]},
 441                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 442                         htons((ecs > 0xffff) ? 0xffff : ecs),
 443                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 444         };
 445
 446         struct iovec iov[IOV_TOTAL] = {
 447                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 448                 [IOV_ORO] = {oro, oro_len},
 449                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 450                 [IOV_CL_ID] = {cl_id, cl_id_len},
 451                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 452                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 453                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 454                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 455                 [IOV_USER_CLASS] = {user_class, user_class_len},
 456                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 457                 [IOV_FQDN] = {&fqdn, fqdn_len},
 458                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 459                 [IOV_IA_NA] = {ia_na, ia_na_len},
 460                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 461         };
 462
 463         size_t cnt = IOV_TOTAL;
 464         if (type == DHCPV6_MSG_INFO_REQ) {
 465                 cnt = 9;
 466                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 467                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 468         } else if (!request_prefix) {
 469                 cnt = 13;
 470         }
 471
 472         // Disable IAs if not used
 473         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 474                 iov[IOV_HDR_IA_NA].iov_len = 0;
 475
 476         if (na_mode == IA_MODE_NONE)
 477                 iov[IOV_HDR_IA_NA].iov_len = 0;
 478
 479         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 480                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 481                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 482
 483         if (!(client_options & DHCPV6_CLIENT_FQDN))
 484                 iov[IOV_FQDN].iov_len = 0;
 485
 486         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 487                 0, ALL_DHCPV6_RELAYS, ifindex};
 488         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 489                         .msg_iov = iov, .msg_iovlen = cnt};
 490
 491         sendmsg(sock, &msg, 0);
 492 }
 493
 494
 495 static int64_t dhcpv6_rand_delay(int64_t time)
 496 {
 497         int random;
 498         odhcp6c_random(&random, sizeof(random));
 499         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 500 }
 501
 502
 503 int dhcpv6_request(enum dhcpv6_msg type)
 504 {
 505         uint8_t rc = 0;
 506         uint64_t timeout = UINT32_MAX;
 507         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 508
 509         if (retx->delay) {
 510                 struct timespec ts = {0, 0};
 511                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
 512                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 513         }
 514
 515         if (type == DHCPV6_MSG_UNKNOWN)
 516                 timeout = t1;
 517         else if (type == DHCPV6_MSG_RENEW)
 518                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 519         else if (type == DHCPV6_MSG_REBIND)
 520                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 521
 522         if (timeout == 0)
 523                 return -1;
 524
 525         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 526                         retx->name, (unsigned long long)timeout, retx->max_rc);
 527
 528         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 529
 530         // Generate transaction ID
 531         uint8_t trid[3] = {0, 0, 0};
 532         if (type != DHCPV6_MSG_UNKNOWN)
 533                 odhcp6c_random(trid, sizeof(trid));
 534         ssize_t len = -1;
 535         int64_t rto = 0;
 536
 537         do {
 538                 if (rto == 0) {
 539                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 540
 541                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 542                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 543                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 544
 545                         rto = (retx->init_timeo * 1000 + delay);
 546                 }
 547                 else
 548                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 549
 550                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 551                         rto = retx->max_timeo * 1000 +
 552                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 553
 554                 // Calculate end for this round and elapsed time
 555                 uint64_t round_end = round_start + rto;
 556                 elapsed = round_start - start;
 557
 558                 // Don't wait too long if timeout differs from infinite
 559                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 560                         round_end = timeout * 1000 + start;
 561
 562                 // Built and send package
 563                 switch (type) {
 564                 case DHCPV6_MSG_UNKNOWN:
 565                         break;
 566                 default:
 567                         syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 568                                         retx->name, (unsigned long long)elapsed, rc);
 569                         // Fall through
 570                 case DHCPV6_MSG_SOLICIT:
 571                 case DHCPV6_MSG_INFO_REQ:
 572                         dhcpv6_send(type, trid, elapsed / 10);
 573                         rc++;
 574                 }
 575
 576                 // Receive rounds
 577                 for (; len < 0 && (round_start < round_end);
 578                                 round_start = odhcp6c_get_milli_time()) {
 579                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 580                         struct iovec iov = {buf, sizeof(buf)};
 581                         struct sockaddr_in6 addr;
 582                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 583                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf,
 584                                         .msg_controllen = sizeof(cmsg_buf)};
 585                         struct in6_pktinfo *pktinfo = NULL;
 586
 587
 588                         // Check for pending signal
 589                         if (odhcp6c_signal_process())
 590                                 return -1;
 591
 592                         // Set timeout for receiving
 593                         uint64_t t = round_end - round_start;
 594                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 595                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 596                                         &tv, sizeof(tv));
 597
 598                         // Receive cycle
 599                         len = recvmsg(sock, &msg, 0);
 600                         if (len < 0)
 601                                 continue;
 602
 603                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 604                                 ch = CMSG_NXTHDR(&msg, ch)) {
 605                                 if (ch->cmsg_level == SOL_IPV6 &&
 606                                         ch->cmsg_type == IPV6_PKTINFO) {
 607                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 608                                         break;
 609                                 }
 610                         }
 611
 612                         if (pktinfo == NULL) {
 613                                 len = -1;
 614                                 continue;
 615                         }
 616
 617                         if (!dhcpv6_response_is_valid(buf, len, trid,
 618                                                         type, &pktinfo->ipi6_addr)) {
 619                                 len = -1;
 620                                 continue;
 621                         }
 622
 623                         uint8_t *opt = &buf[4];
 624                         uint8_t *opt_end = opt + len - 4;
 625
 626                         round_start = odhcp6c_get_milli_time();
 627                         elapsed = round_start - start;
 628                         syslog(LOG_NOTICE, "Got a valid reply after "
 629                                         "%llums", (unsigned long long)elapsed);
 630
 631                         if (retx->handler_reply)
 632                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 633
 634                         if (len > 0 && round_end - round_start > 1000)
 635                                 round_end = 1000 + round_start;
 636                 }
 637
 638                 // Allow
 639                 if (retx->handler_finish)
 640                         len = retx->handler_finish();
 641         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 642                         (!retx->max_rc || rc < retx->max_rc));
 643         return len;
 644 }
 645
 646 // Message validation checks according to RFC3315 chapter 15
 647 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 648                 const uint8_t transaction[3], enum dhcpv6_msg type,
 649                 const struct in6_addr *daddr)
 650 {
 651         const struct dhcpv6_header *rep = buf;
 652         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 653                         transaction, sizeof(rep->tr_id)))
 654                 return false; // Invalid reply
 655
 656         if (type == DHCPV6_MSG_SOLICIT) {
 657                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 658                                 rep->msg_type != DHCPV6_MSG_REPLY)
 659                         return false;
 660         } else if (type == DHCPV6_MSG_UNKNOWN) {
 661                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 662                         return false;
 663         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 664                 return false;
 665         }
 666
 667         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 668                 rcmsg = DHCPV6_MSG_UNKNOWN;
 669         uint16_t otype, olen = UINT16_MAX;
 670         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 671                 ia_present = false, options_valid = true;
 672
 673         size_t client_id_len, server_id_len;
 674         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 675         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 676
 677         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 678                 if (otype == DHCPV6_OPT_CLIENTID) {
 679                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 680                                         &odata[-4], client_id, client_id_len);
 681                 } else if (otype == DHCPV6_OPT_SERVERID) {
 682                         if (server_id_len)
 683                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 684                                                 &odata[-4], server_id, server_id_len);
 685                         else
 686                                 serverid_ok = true;
 687                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 688                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 689                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 690                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 691                                 continue;
 692
 693                         md5_ctx_t md5;
 694                         uint8_t serverhash[16], secretbytes[64], hash[16];
 695                         memcpy(serverhash, r->key, sizeof(serverhash));
 696                         memset(r->key, 0, sizeof(r->key));
 697
 698                         memset(secretbytes, 0, sizeof(secretbytes));
 699                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 700
 701                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 702                                 secretbytes[i] ^= 0x36;
 703
 704                         md5_begin(&md5);
 705                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 706                         md5_hash(buf, len, &md5);
 707                         md5_end(hash, &md5);
 708
 709                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 710                                 secretbytes[i] ^= 0x36;
 711                                 secretbytes[i] ^= 0x5c;
 712                         }
 713
 714                         md5_begin(&md5);
 715                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 716                         md5_hash(hash, 16, &md5);
 717                         md5_end(hash, &md5);
 718
 719                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 720                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 721                         rcmsg = odata[0];
 722                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 723                         ia_present = true;
 724                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 725                                 options_valid = false;
 726                 }
 727                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 728                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 729                         // Options are not allowed on global level
 730                         options_valid = false;
 731                 }
 732         }
 733
 734         if (!options_valid || ((odata + olen) > end))
 735                 return false;
 736
 737         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 738                 return false;
 739
 740         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 741                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 742                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 743                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 744                         return false;
 745         }
 746
 747         return clientid_ok && serverid_ok;
 748 }
 749
 750
 751 int dhcpv6_poll_reconfigure(void)
 752 {
 753         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 754         if (ret != -1)
 755                 ret = dhcpv6_request(ret);
 756
 757         return ret;
 758 }
 759
 760
 761 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 762                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 763 {
 764         uint16_t otype, olen;
 765         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 766         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 767                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 768                                 odata[0] == DHCPV6_MSG_RENEW ||
 769                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 770                         msg = odata[0];
 771
 772         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL, NULL);
 773         return msg;
 774 }
 775
 776
 777 // Collect all advertised servers
 778 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 779                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 780 {
 781         uint16_t olen, otype;
 782         uint8_t *odata, pref = 0;
 783         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 784                                         DHCPV6_SOL_MAX_RT,
 785                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 786         bool have_na = false;
 787         int have_pd = 0;
 788
 789         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 790                 if (orig == DHCPV6_MSG_SOLICIT &&
 791                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 792                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 793                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 794                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 795                 }
 796
 797                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 798                         memcpy(cand.duid, odata, olen);
 799                         cand.duid_len = olen;
 800                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 801                                 cand.preference >= 0) {
 802                         cand.preference = pref = odata[0];
 803                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 804                         cand.wants_reconfigure = true;
 805                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 806                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 807                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 808                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 809                                 cand.sol_max_rt = sol_max_rt;
 810                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 811                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 812                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 813                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 814                                 cand.inf_max_rt = inf_max_rt;
 815                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 816                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 817                         uint8_t *oend = odata + olen, *d;
 818                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 819                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 820                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 821                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 822                                         have_pd = p->prefix;
 823                                 }
 824                         }
 825                 } else if (otype == DHCPV6_OPT_IA_NA) {
 826                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 827                         uint8_t *oend = odata + olen, *d;
 828                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 829                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 830                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 831                                         have_na = true;
 832                 }
 833         }
 834
 835         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 836                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 837                 /*
 838                  * RFC7083 states to process the SOL_MAX_RT and
 839                  * INF_MAX_RT options even if the DHCPv6 server
 840                  * did not propose any IA_NA and/or IA_PD
 841                  */
 842                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 843                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 844                 return -1;
 845         }
 846
 847         if (na_mode != IA_MODE_NONE && !have_na) {
 848                 cand.has_noaddravail = true;
 849                 cand.preference -= 1000;
 850         }
 851
 852         if (pd_mode != IA_MODE_NONE) {
 853                 if (have_pd)
 854                         cand.preference += 2000 + (128 - have_pd);
 855                 else
 856                         cand.preference -= 2000;
 857         }
 858
 859         if (cand.duid_len > 0) {
 860                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 861                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 862                 dhcpv6_add_server_cand(&cand);
 863         }
 864
 865         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 866 }
 867
 868
 869 static int dhcpv6_commit_advert(void)
 870 {
 871         return dhcpv6_promote_server_cand();
 872 }
 873
 874
 875 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 876                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 877 {
 878         dhcpv6_handle_advert(orig, rc, opt, end, from);
 879         if (dhcpv6_commit_advert() < 0)
 880                 return -1;
 881
 882         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 883 }
 884
 885
 886 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 887                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 888 {
 889         uint8_t *odata;
 890         uint16_t otype, olen;
 891         uint32_t refresh = 86400;
 892         int ret = 1;
 893         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 894
 895         odhcp6c_expire();
 896
 897         if (orig == DHCPV6_MSG_UNKNOWN) {
 898                 static time_t last_update = 0;
 899                 time_t now = odhcp6c_get_milli_time() / 1000;
 900
 901                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 902                 last_update = now;
 903
 904                 if (t1 != UINT32_MAX)
 905                         t1 -= elapsed;
 906
 907                 if (t2 != UINT32_MAX)
 908                         t2 -= elapsed;
 909
 910                 if (t3 != UINT32_MAX)
 911                         t3 -= elapsed;
 912
 913                 if (t1 < 0)
 914                         t1 = 0;
 915
 916                 if (t2 < 0)
 917                         t2 = 0;
 918
 919                 if (t3 < 0)
 920                         t3 = 0;
 921         }
 922
 923         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 924                 // Delete NA and PD we have in the state from the Advert
 925                 odhcp6c_clear_state(STATE_IA_NA);
 926                 odhcp6c_clear_state(STATE_IA_PD);
 927         }
 928
 929         if (opt) {
 930                 odhcp6c_clear_state(STATE_DNS);
 931                 odhcp6c_clear_state(STATE_SEARCH);
 932                 odhcp6c_clear_state(STATE_SNTP_IP);
 933                 odhcp6c_clear_state(STATE_NTP_IP);
 934                 odhcp6c_clear_state(STATE_NTP_FQDN);
 935                 odhcp6c_clear_state(STATE_SIP_IP);
 936                 odhcp6c_clear_state(STATE_SIP_FQDN);
 937                 odhcp6c_clear_state(STATE_AFTR_NAME);
 938                 odhcp6c_clear_state(STATE_CER);
 939                 odhcp6c_clear_state(STATE_S46_MAPT);
 940                 odhcp6c_clear_state(STATE_S46_MAPE);
 941                 odhcp6c_clear_state(STATE_S46_LW);
 942                 odhcp6c_clear_state(STATE_PASSTHRU);
 943                 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 944
 945                 // Parse and find all matching IAs
 946                 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 947                         bool passthru = true;
 948
 949                         if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 950                                         && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 951                                 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 952
 953                                 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
 954                                         (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
 955                                         continue;
 956
 957                                 // Test ID
 958                                 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
 959                                         continue;
 960
 961                                 uint16_t code = DHCPV6_Success;
 962                                 uint16_t stype, slen;
 963                                 uint8_t *sdata;
 964                                 // Get and handle status code
 965                                 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 966                                                 stype, slen, sdata) {
 967                                         if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 968                                                 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 969                                                 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 970
 971                                                 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 972
 973                                                 if (code == DHCPV6_Success)
 974                                                         continue;
 975
 976                                                 dhcpv6_handle_ia_status_code(orig, ia_hdr,
 977                                                         code, mdata, mlen, handled_status_codes, &ret);
 978
 979
 980                                                 if (ret > 0)
 981                                                         return ret;
 982                                                 break;
 983                                         }
 984                                 }
 985
 986                                 if (code != DHCPV6_Success)
 987                                         continue;
 988
 989                                 dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 990                                 passthru = false;
 991                         } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 992                                 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 993                                 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 994                                 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 995
 996                                 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 997                                 passthru = false;
 998                         }
 999                         else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1000                                 if (olen % 16 == 0)
1001                                         odhcp6c_add_state(STATE_DNS, odata, olen);
1002                         } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
1003                                 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1004                         } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1005                                 if (olen % 16 == 0)
1006                                         odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1007                         } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1008                                 uint16_t stype, slen;
1009                                 uint8_t *sdata;
1010                                 // Test status and bail if error
1011                                 dhcpv6_for_each_option(odata, odata + olen,
1012                                                 stype, slen, sdata) {
1013                                         if (slen == 16 && (stype == NTP_MC_ADDR ||
1014                                                         stype == NTP_SRV_ADDR))
1015                                                 odhcp6c_add_state(STATE_NTP_IP,
1016                                                                 sdata, slen);
1017                                         else if (slen > 0 && stype == NTP_SRV_FQDN)
1018                                                 odhcp6c_add_state(STATE_NTP_FQDN,
1019                                                                 sdata, slen);
1020                                 }
1021                         } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1022                                 if (olen == 16)
1023                                         odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1024                         } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1025                                 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1026                         } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1027                                 refresh = ntohl(*((uint32_t*)odata));
1028                                 passthru = false;
1029                         } else if (otype == DHCPV6_OPT_AUTH) {
1030                                 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1031                                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1032                                         if (r->protocol == 3 && r->algorithm == 1 &&
1033                                                         r->reconf_type == 1)
1034                                                 memcpy(reconf_key, r->key, sizeof(r->key));
1035                                 }
1036                                 passthru = false;
1037                         } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1038                                 size_t cur_len;
1039                                 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1040                                 if (cur_len == 0)
1041                                         odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1042                                 passthru = false;
1043                         } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1044                                 uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1045                                 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1046                                                 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1047                                         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1048                                 passthru = false;
1049                         } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1050                                 uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1051                                 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1052                                                 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1053                                         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1054                                 passthru = false;
1055         #ifdef EXT_CER_ID
1056                         } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1057                                         sizeof(struct dhcpv6_cer_id)) {
1058                                 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1059                                 struct in6_addr any = IN6ADDR_ANY_INIT;
1060                                 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1061                                         odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1062                                 passthru = false;
1063         #endif
1064                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1065                                 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1066                                 passthru = false;
1067                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1068                                 size_t mape_len;
1069                                 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1070                                 if (mape_len == 0)
1071                                         odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1072                                 passthru = false;
1073                         } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1074                                 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1075                                 passthru = false;
1076                         } else if (otype == DHCPV6_OPT_CLIENTID ||
1077                                         otype == DHCPV6_OPT_SERVERID ||
1078                                         otype == DHCPV6_OPT_IA_TA ||
1079                                         otype == DHCPV6_OPT_PREF ||
1080                                         otype == DHCPV6_OPT_UNICAST ||
1081                                         otype == DHCPV6_OPT_FQDN ||
1082                                         otype == DHCPV6_OPT_RECONF_ACCEPT) {
1083                                 passthru = false;
1084                         } else {
1085                                 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1086                         }
1087
1088                         if (passthru)
1089                                 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1090                 }
1091         }
1092
1093         if (orig != DHCPV6_MSG_INFO_REQ) {
1094                 // Update refresh timers if no fatal status code was received
1095                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1096                         switch (orig) {
1097                         case DHCPV6_MSG_RENEW:
1098                                 // Send further renews if T1 is not set
1099                                 if (!t1)
1100                                         ret = -1;
1101                                 break;
1102                         case DHCPV6_MSG_REBIND:
1103                                 // Send further rebinds if T1 and T2 is not set
1104                                 if (!t1 && !t2)
1105                                         ret = -1;
1106                                 break;
1107
1108                         case DHCPV6_MSG_REQUEST:
1109                                 // All server candidates can be cleared if not yet bound
1110                                 if (!odhcp6c_is_bound())
1111                                         dhcpv6_clear_all_server_cand();
1112
1113                         default :
1114                                 break;
1115                         }
1116
1117                         if (orig == DHCPV6_MSG_REBIND || orig == DHCPV6_MSG_REQUEST) {
1118                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1119                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1120                         }
1121                 }
1122         }
1123         else if (ret > 0) {
1124                 // All server candidates can be cleared if not yet bound
1125                 if (!odhcp6c_is_bound())
1126                         dhcpv6_clear_all_server_cand();
1127
1128                 t1 = refresh;
1129         }
1130
1131         return ret;
1132 }
1133
1134
1135 static int dhcpv6_parse_ia(void *opt, void *end)
1136 {
1137         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1138         int parsed_ia = 0;
1139         uint32_t t1, t2;
1140         uint16_t otype, olen;
1141         uint8_t *odata;
1142
1143         t1 = ntohl(ia_hdr->t1);
1144         t2 = ntohl(ia_hdr->t2);
1145
1146         if (t1 > t2)
1147                 return 0;
1148
1149         // Update address IA
1150         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1151                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1152                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1153
1154                 entry.iaid = ia_hdr->iaid;
1155
1156                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1157                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1158                         if (olen + 4U < sizeof(*prefix))
1159                                 continue;
1160
1161                         entry.valid = ntohl(prefix->valid);
1162                         entry.preferred = ntohl(prefix->preferred);
1163
1164                         if (entry.preferred > entry.valid)
1165                                 continue;
1166
1167                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1168                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1169                         if (entry.t1 > entry.t2)
1170                                 entry.t1 = entry.t2;
1171
1172                         entry.length = prefix->prefix;
1173                         entry.target = prefix->addr;
1174                         uint16_t stype, slen;
1175                         uint8_t *sdata;
1176
1177                         // Parse PD-exclude
1178                         bool ok = true;
1179                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1180                                         odata + olen, stype, slen, sdata) {
1181                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1182                                         continue;
1183
1184                                 uint8_t elen = sdata[0];
1185                                 if (elen > 64)
1186                                         elen = 64;
1187
1188                                 if (elen <= 32 || elen <= entry.length) {
1189                                         ok = false;
1190                                         continue;
1191                                 }
1192
1193
1194                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1195                                 if (slen <= bytes) {
1196                                         ok = false;
1197                                         continue;
1198                                 }
1199
1200                                 uint32_t exclude = 0;
1201                                 do {
1202                                         exclude = exclude << 8 | sdata[bytes];
1203                                 } while (--bytes);
1204
1205                                 exclude >>= 8 - ((elen - entry.length) % 8);
1206                                 exclude <<= 64 - elen;
1207
1208                                 // Abusing router & priority fields for exclusion
1209                                 entry.router = entry.target;
1210                                 entry.router.s6_addr32[1] |= htonl(exclude);
1211                                 entry.priority = elen;
1212                         }
1213
1214                         if (ok) {
1215                                 odhcp6c_update_entry(STATE_IA_PD, &entry, 0, false);
1216                                 parsed_ia++;
1217                         }
1218
1219                         entry.priority = 0;
1220                         memset(&entry.router, 0, sizeof(entry.router));
1221                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1222                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1223                         if (olen + 4U < sizeof(*addr))
1224                                 continue;
1225
1226                         entry.preferred = ntohl(addr->preferred);
1227                         entry.valid = ntohl(addr->valid);
1228
1229                         if (entry.preferred > entry.valid)
1230                                 continue;
1231
1232                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1233                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1234                         if (entry.t1 > entry.t2)
1235                                 entry.t1 = entry.t2;
1236
1237                         entry.length = 128;
1238                         entry.target = addr->addr;
1239
1240                         odhcp6c_update_entry(STATE_IA_NA, &entry, 0, false);
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         default:
1360                 *ret = 0;
1361                 break;
1362         }
1363 }
1364
1365 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1366 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1367 {
1368         size_t cand_len, i;
1369         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1370
1371         // Remove identical duid server candidate
1372         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1373                 if (cand->duid_len == c[i].duid_len &&
1374                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1375                         free(c[i].ia_na);
1376                         free(c[i].ia_pd);
1377                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1378                         break;
1379                 }
1380         }
1381
1382         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1383                 i < cand_len / sizeof(*c); ++i) {
1384                 if (c[i].preference < cand->preference)
1385                         break;
1386         }
1387
1388         if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1389                 free(cand->ia_na);
1390                 free(cand->ia_pd);
1391         }
1392 }
1393
1394 static void dhcpv6_clear_all_server_cand(void)
1395 {
1396         size_t cand_len, i;
1397         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1398
1399         // Server candidates need deep delete for IA_NA/IA_PD
1400         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1401                 free(c[i].ia_na);
1402                 free(c[i].ia_pd);
1403         }
1404         odhcp6c_clear_state(STATE_SERVER_CAND);
1405 }
1406
1407 int dhcpv6_promote_server_cand(void)
1408 {
1409         size_t cand_len;
1410         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1411         uint16_t hdr[2];
1412         int ret = DHCPV6_STATELESS;
1413
1414         // Clear lingering candidate state info
1415         odhcp6c_clear_state(STATE_SERVER_ID);
1416         odhcp6c_clear_state(STATE_IA_NA);
1417         odhcp6c_clear_state(STATE_IA_PD);
1418
1419         if (!cand_len)
1420                 return -1;
1421
1422         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1423                 na_mode = IA_MODE_NONE;
1424
1425                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1426                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1427
1428                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1429         }
1430
1431         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1432         hdr[1] = htons(cand->duid_len);
1433         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1434         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1435         accept_reconfig = cand->wants_reconfigure;
1436         if (cand->ia_na_len) {
1437                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1438                 free(cand->ia_na);
1439                 if (na_mode != IA_MODE_NONE)
1440                         ret = DHCPV6_STATEFUL;
1441         }
1442         if (cand->ia_pd_len) {
1443                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1444                 free(cand->ia_pd);
1445                 if (request_prefix)
1446                         ret = DHCPV6_STATEFUL;
1447         }
1448
1449         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1450         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1451
1452         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1453
1454         return ret;
1455 }