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 #ifdef EXT_S46
 183                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 184                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 185                         htons(DHCPV6_OPT_S46_CONT_LW),
 186 #endif
 187                 };
 188                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 189         }
 190
 191         // Configure IPv6-options
 192         int val = 1;
 193         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 194         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 195         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 196         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 197
 198         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 199                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 200         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 201                 return -1;
 202
 203         return 0;
 204 }
 205
 206 enum {
 207         IOV_HDR=0,
 208         IOV_ORO,
 209         IOV_ORO_REFRESH,
 210         IOV_CL_ID,
 211         IOV_SRV_ID,
 212         IOV_VENDOR_CLASS_HDR,
 213         IOV_VENDOR_CLASS,
 214         IOV_USER_CLASS_HDR,
 215         IOV_USER_CLASS,
 216         IOV_RECONF_ACCEPT,
 217         IOV_FQDN,
 218         IOV_HDR_IA_NA,
 219         IOV_IA_NA,
 220         IOV_IA_PD,
 221         IOV_TOTAL
 222 };
 223
 224 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 225 {
 226         na_mode = na;
 227         pd_mode = pd;
 228 }
 229
 230 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 231 {
 232         // Build FQDN
 233         char fqdn_buf[256];
 234         gethostname(fqdn_buf, sizeof(fqdn_buf));
 235         struct {
 236                 uint16_t type;
 237                 uint16_t len;
 238                 uint8_t flags;
 239                 uint8_t data[256];
 240         } fqdn;
 241         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 242                         sizeof(fqdn.data), NULL, NULL);
 243         fqdn.type = htons(DHCPV6_OPT_FQDN);
 244         fqdn.len = htons(fqdn_len - 4);
 245         fqdn.flags = 0;
 246
 247
 248         // Build Client ID
 249         size_t cl_id_len;
 250         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 251
 252         // Get Server ID
 253         size_t srv_id_len;
 254         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 255
 256         // Build IA_PDs
 257         size_t ia_pd_entries = 0, ia_pd_len = 0;
 258         uint8_t *ia_pd;
 259
 260         if (type == DHCPV6_MSG_SOLICIT) {
 261                 odhcp6c_clear_state(STATE_IA_PD);
 262                 size_t n_prefixes;
 263                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 264                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 265
 266                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 267
 268                 for (size_t i = 0; i < n_prefixes; i++) {
 269                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 270                                 htons(DHCPV6_OPT_IA_PD),
 271                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 272                                 request_prefixes[i].iaid, 0, 0
 273                         };
 274                         struct dhcpv6_ia_prefix pref = {
 275                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 276                                 .len = htons(25), .prefix = request_prefixes[i].length
 277                         };
 278                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 279                         ia_pd_len += sizeof(hdr_ia_pd);
 280                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 281                         ia_pd_len += sizeof(pref);
 282                 }
 283         } else {
 284                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 285                 ia_pd_entries /= sizeof(*e);
 286
 287                 // we're too lazy to count our distinct IAIDs,
 288                 // so just allocate maximally needed space
 289                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 290                                         sizeof(struct dhcpv6_ia_hdr)));
 291
 292                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 293                         uint32_t iaid = e[i].iaid;
 294
 295                         // check if this is an unprocessed IAID and skip if not.
 296                         int new_iaid = 1;
 297                         for (int j = i-1; j >= 0; j--) {
 298                                 if (e[j].iaid == iaid) {
 299                                         new_iaid = 0;
 300                                         break;
 301                                 }
 302                         }
 303
 304                         if (!new_iaid)
 305                                 continue;
 306
 307                         // construct header
 308                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 309                                 htons(DHCPV6_OPT_IA_PD),
 310                                 htons(sizeof(hdr_ia_pd) - 4),
 311                                 iaid, 0, 0
 312                         };
 313
 314                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 315                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 316                         ia_pd_len += sizeof(hdr_ia_pd);
 317
 318                         for (size_t j = i; j < ia_pd_entries; j++) {
 319                                 if (e[j].iaid != iaid)
 320                                         continue;
 321
 322                                 uint8_t ex_len = 0;
 323                                 if (e[j].priority > 0)
 324                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 325
 326                                 struct dhcpv6_ia_prefix p = {
 327                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 328                                         .len = htons(sizeof(p) - 4U + ex_len),
 329                                         .prefix = e[j].length,
 330                                         .addr = e[j].target
 331                                 };
 332
 333                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 334                                 ia_pd_len += sizeof(p);
 335
 336                                 if (ex_len) {
 337                                         ia_pd[ia_pd_len++] = 0;
 338                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 339                                         ia_pd[ia_pd_len++] = 0;
 340                                         ia_pd[ia_pd_len++] = ex_len - 4;
 341                                         ia_pd[ia_pd_len++] = e[j].priority;
 342
 343                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 344                                         excl >>= (64 - e[j].priority);
 345                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 346
 347                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 348                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 349                                         ia_pd_len += ex_len - 5;
 350                                 }
 351
 352                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 353                         }
 354                 }
 355         }
 356
 357         if (ia_pd_entries > 0)
 358                 request_prefix = 1;
 359
 360         // Build IA_NAs
 361         size_t ia_na_entries, ia_na_len = 0;
 362         void *ia_na = NULL;
 363         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 364         ia_na_entries /= sizeof(*e);
 365
 366         struct dhcpv6_ia_hdr hdr_ia_na = {
 367                 htons(DHCPV6_OPT_IA_NA),
 368                 htons(sizeof(hdr_ia_na) - 4),
 369                 1, 0, 0
 370         };
 371
 372         struct dhcpv6_ia_addr pa[ia_na_entries];
 373         for (size_t i = 0; i < ia_na_entries; ++i) {
 374                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 375                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 376                 pa[i].addr = e[i].target;
 377                 pa[i].preferred = 0;
 378                 pa[i].valid = 0;
 379         }
 380
 381         ia_na = pa;
 382         ia_na_len = sizeof(pa);
 383         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 384
 385         // Reconfigure Accept
 386         struct {
 387                 uint16_t type;
 388                 uint16_t length;
 389         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 390
 391         // Request Information Refresh
 392         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 393
 394         // Build vendor-class option
 395         size_t vendor_class_len, user_class_len;
 396         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 397         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 398
 399         struct {
 400                 uint16_t type;
 401                 uint16_t length;
 402         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 403
 404         struct {
 405                 uint16_t type;
 406                 uint16_t length;
 407         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 408
 409         // Prepare Header
 410         size_t oro_len;
 411         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 412         struct {
 413                 uint8_t type;
 414                 uint8_t trid[3];
 415                 uint16_t elapsed_type;
 416                 uint16_t elapsed_len;
 417                 uint16_t elapsed_value;
 418                 uint16_t oro_type;
 419                 uint16_t oro_len;
 420         } hdr = {
 421                 type, {trid[0], trid[1], trid[2]},
 422                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 423                         htons((ecs > 0xffff) ? 0xffff : ecs),
 424                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 425         };
 426
 427         struct iovec iov[IOV_TOTAL] = {
 428                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 429                 [IOV_ORO] = {oro, oro_len},
 430                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 431                 [IOV_CL_ID] = {cl_id, cl_id_len},
 432                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 433                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 434                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 435                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 436                 [IOV_USER_CLASS] = {user_class, user_class_len},
 437                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 438                 [IOV_FQDN] = {&fqdn, fqdn_len},
 439                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 440                 [IOV_IA_NA] = {ia_na, ia_na_len},
 441                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 442         };
 443
 444         size_t cnt = IOV_TOTAL;
 445         if (type == DHCPV6_MSG_INFO_REQ) {
 446                 cnt = 9;
 447                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 448                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 449         } else if (!request_prefix) {
 450                 cnt = 13;
 451         }
 452
 453         // Disable IAs if not used
 454         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 455                 iov[IOV_HDR_IA_NA].iov_len = 0;
 456
 457         if (na_mode == IA_MODE_NONE)
 458                 iov[IOV_HDR_IA_NA].iov_len = 0;
 459
 460         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 461                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 462                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 463
 464         if (!(client_options & DHCPV6_CLIENT_FQDN))
 465                 iov[IOV_FQDN].iov_len = 0;
 466
 467         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 468                 0, ALL_DHCPV6_RELAYS, ifindex};
 469         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 470
 471         sendmsg(sock, &msg, 0);
 472 }
 473
 474
 475 static int64_t dhcpv6_rand_delay(int64_t time)
 476 {
 477         int random;
 478         odhcp6c_random(&random, sizeof(random));
 479         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 480 }
 481
 482
 483 int dhcpv6_request(enum dhcpv6_msg type)
 484 {
 485         uint8_t rc = 0;
 486         uint64_t timeout = UINT32_MAX;
 487         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 488
 489         if (retx->delay) {
 490                 struct timespec ts = {0, 0};
 491                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 492                 nanosleep(&ts, NULL);
 493         }
 494
 495         if (type == DHCPV6_MSG_UNKNOWN)
 496                 timeout = t1;
 497         else if (type == DHCPV6_MSG_RENEW)
 498                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 499         else if (type == DHCPV6_MSG_REBIND)
 500                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 501
 502         if (timeout == 0)
 503                 return -1;
 504
 505         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 506                         retx->name, (unsigned long long)timeout, retx->max_rc);
 507
 508         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 509
 510         // Generate transaction ID
 511         uint8_t trid[3] = {0, 0, 0};
 512         if (type != DHCPV6_MSG_UNKNOWN)
 513                 odhcp6c_random(trid, sizeof(trid));
 514         ssize_t len = -1;
 515         int64_t rto = 0;
 516
 517         do {
 518                 if (rto == 0) {
 519                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 520
 521                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 522                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 523                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 524
 525                         rto = (retx->init_timeo * 1000 + delay);
 526                 }
 527                 else
 528                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 529
 530                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 531                         rto = retx->max_timeo * 1000 +
 532                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 533
 534                 // Calculate end for this round and elapsed time
 535                 uint64_t round_end = round_start + rto;
 536                 elapsed = round_start - start;
 537
 538                 // Don't wait too long if timeout differs from infinite
 539                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 540                         round_end = timeout * 1000 + start;
 541
 542                 // Built and send package
 543                 if (type != DHCPV6_MSG_UNKNOWN) {
 544                         if (type != DHCPV6_MSG_SOLICIT)
 545                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 546                                                 retx->name, (unsigned long long)elapsed, rc);
 547                         dhcpv6_send(type, trid, elapsed / 10);
 548                         rc++;
 549                 }
 550
 551                 // Receive rounds
 552                 for (; len < 0 && (round_start < round_end);
 553                                 round_start = odhcp6c_get_milli_time()) {
 554                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 555                         struct iovec iov = {buf, sizeof(buf)};
 556                         struct msghdr msg = {NULL, 0, &iov, 1,
 557                                         cmsg_buf, sizeof(cmsg_buf), 0};
 558                         struct in6_pktinfo *pktinfo = NULL;
 559
 560                         // Check for pending signal
 561                         if (odhcp6c_signal_process())
 562                                 return -1;
 563
 564                         // Set timeout for receiving
 565                         uint64_t t = round_end - round_start;
 566                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 567                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 568                                         &tv, sizeof(tv));
 569
 570                         // Receive cycle
 571                         len = recvmsg(sock, &msg, 0);
 572                         if (len < 0)
 573                                 continue;
 574
 575                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 576                                 ch = CMSG_NXTHDR(&msg, ch)) {
 577                                 if (ch->cmsg_level == SOL_IPV6 &&
 578                                         ch->cmsg_type == IPV6_PKTINFO) {
 579                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 580                                         break;
 581                                 }
 582                         }
 583
 584                         if (pktinfo == NULL) {
 585                                 len = -1;
 586                                 continue;
 587                         }
 588
 589                         if (!dhcpv6_response_is_valid(buf, len, trid,
 590                                                         type, &pktinfo->ipi6_addr)) {
 591                                 len = -1;
 592                                 continue;
 593                         }
 594
 595                         uint8_t *opt = &buf[4];
 596                         uint8_t *opt_end = opt + len - 4;
 597
 598                         round_start = odhcp6c_get_milli_time();
 599                         elapsed = round_start - start;
 600                         syslog(LOG_NOTICE, "Got a valid reply after "
 601                                         "%llums", (unsigned long long)elapsed);
 602
 603                         if (retx->handler_reply)
 604                                 len = retx->handler_reply(type, rc, opt, opt_end);
 605
 606                         if (len > 0 && round_end - round_start > 1000)
 607                                 round_end = 1000 + round_start;
 608                 }
 609
 610                 // Allow
 611                 if (retx->handler_finish)
 612                         len = retx->handler_finish();
 613         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 614                         (!retx->max_rc || rc < retx->max_rc));
 615         return len;
 616 }
 617
 618 // Message validation checks according to RFC3315 chapter 15
 619 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 620                 const uint8_t transaction[3], enum dhcpv6_msg type,
 621                 const struct in6_addr *daddr)
 622 {
 623         const struct dhcpv6_header *rep = buf;
 624         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 625                         transaction, sizeof(rep->tr_id)))
 626                 return false; // Invalid reply
 627
 628         if (type == DHCPV6_MSG_SOLICIT) {
 629                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 630                                 rep->msg_type != DHCPV6_MSG_REPLY)
 631                         return false;
 632         } else if (type == DHCPV6_MSG_UNKNOWN) {
 633                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 634                         return false;
 635         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 636                 return false;
 637         }
 638
 639         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 640                 rcmsg = DHCPV6_MSG_UNKNOWN;
 641         uint16_t otype, olen = UINT16_MAX;
 642         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 643                 ia_present = false, options_valid = true;
 644
 645         size_t client_id_len, server_id_len;
 646         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 647         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 648
 649         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 650                 if (otype == DHCPV6_OPT_CLIENTID) {
 651                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 652                                         &odata[-4], client_id, client_id_len);
 653                 } else if (otype == DHCPV6_OPT_SERVERID) {
 654                         if (server_id_len)
 655                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 656                                                 &odata[-4], server_id, server_id_len);
 657                         else
 658                                 serverid_ok = true;
 659                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 660                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 661                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 662                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 663                                 continue;
 664
 665                         md5_ctx_t md5;
 666                         uint8_t serverhash[16], secretbytes[64], hash[16];
 667                         memcpy(serverhash, r->key, sizeof(serverhash));
 668                         memset(r->key, 0, sizeof(r->key));
 669
 670                         memset(secretbytes, 0, sizeof(secretbytes));
 671                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 672
 673                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 674                                 secretbytes[i] ^= 0x36;
 675
 676                         md5_begin(&md5);
 677                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 678                         md5_hash(buf, len, &md5);
 679                         md5_end(hash, &md5);
 680
 681                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 682                                 secretbytes[i] ^= 0x36;
 683                                 secretbytes[i] ^= 0x5c;
 684                         }
 685
 686                         md5_begin(&md5);
 687                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 688                         md5_hash(hash, 16, &md5);
 689                         md5_end(hash, &md5);
 690
 691                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 692                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 693                         rcmsg = odata[0];
 694                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 695                         ia_present = true;
 696                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 697                                 options_valid = false;
 698                 }
 699                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 700                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 701                         // Options are not allowed on global level
 702                         options_valid = false;
 703                 }
 704         }
 705
 706         if (!options_valid || ((odata + olen) > end))
 707                 return false;
 708
 709         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 710                 return false;
 711
 712         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 713                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 714                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 715                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 716                         return false;
 717         }
 718
 719         return clientid_ok && serverid_ok;
 720 }
 721
 722
 723 int dhcpv6_poll_reconfigure(void)
 724 {
 725         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 726         if (ret != -1)
 727                 ret = dhcpv6_request(ret);
 728
 729         return ret;
 730 }
 731
 732
 733 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 734                 const void *opt, const void *end)
 735 {
 736         uint16_t otype, olen;
 737         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 738         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 739                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 740                                 odata[0] == DHCPV6_MSG_RENEW ||
 741                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 742                         msg = odata[0];
 743
 744         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 745         return msg;
 746 }
 747
 748
 749 // Collect all advertised servers
 750 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 751                 const void *opt, const void *end)
 752 {
 753         uint16_t olen, otype;
 754         uint8_t *odata, pref = 0;
 755         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 756                                         DHCPV6_SOL_MAX_RT,
 757                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 758         bool have_na = false;
 759         int have_pd = 0;
 760
 761         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 762                 if (orig == DHCPV6_MSG_SOLICIT &&
 763                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 764                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 765                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 766                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 767                 }
 768
 769                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 770                         memcpy(cand.duid, odata, olen);
 771                         cand.duid_len = olen;
 772                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 773                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 774
 775                         switch (error) {
 776                         case DHCPV6_NoPrefixAvail:
 777                                 // Status code on global level
 778                                 cand.preference -= 2000;
 779                                 break;
 780
 781                         default :
 782                                 break;
 783                         }
 784                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 785                                 cand.preference >= 0) {
 786                         cand.preference = pref = odata[0];
 787                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 788                         cand.wants_reconfigure = true;
 789                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 790                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 791                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 792                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 793                                 cand.sol_max_rt = sol_max_rt;
 794                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 795                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 796                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 797                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 798                                 cand.inf_max_rt = inf_max_rt;
 799                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 800                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 801                         uint8_t *oend = odata + olen, *d;
 802                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 803                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 804                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 805                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 806                                         have_pd = p->prefix;
 807                                 }
 808                         }
 809                 } else if (otype == DHCPV6_OPT_IA_NA) {
 810                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 811                         uint8_t *oend = odata + olen, *d;
 812                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 813                                 if (otype == DHCPV6_OPT_IA_ADDR)
 814                                         have_na = true;
 815                 }
 816         }
 817
 818         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 819                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 820                 /*
 821                  * RFC7083 states to process the SOL_MAX_RT and
 822                  * INF_MAX_RT options even if the DHCPv6 server
 823                  * did not propose any IA_NA and/or IA_PD
 824                  */
 825                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 826                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 827                 return -1;
 828         }
 829
 830         if (na_mode != IA_MODE_NONE && !have_na) {
 831                 cand.has_noaddravail = true;
 832                 cand.preference -= 1000;
 833         }
 834
 835         if (pd_mode != IA_MODE_NONE) {
 836                 if (have_pd)
 837                         cand.preference += 2000 + (128 - have_pd);
 838                 else
 839                         cand.preference -= 2000;
 840         }
 841
 842         if (cand.duid_len > 0) {
 843                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 844                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 845                 dhcpv6_add_server_cand(&cand);
 846         }
 847
 848         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 849 }
 850
 851
 852 static int dhcpv6_commit_advert(void)
 853 {
 854         return dhcpv6_promote_server_cand();
 855 }
 856
 857
 858 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 859                 const void *opt, const void *end)
 860 {
 861         dhcpv6_handle_advert(orig, rc, opt, end);
 862         if (dhcpv6_commit_advert() < 0)
 863                 return -1;
 864
 865         return dhcpv6_handle_reply(orig, rc, opt, end);
 866 }
 867
 868
 869 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 870                 const void *opt, const void *end)
 871 {
 872         uint8_t *odata;
 873         uint16_t otype, olen;
 874         uint32_t refresh = UINT32_MAX;
 875         int ret = 1;
 876         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 877
 878         odhcp6c_expire();
 879
 880         if (orig == DHCPV6_MSG_UNKNOWN) {
 881                 static time_t last_update = 0;
 882                 time_t now = odhcp6c_get_milli_time() / 1000;
 883
 884                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 885                 last_update = now;
 886
 887                 if (t1 != UINT32_MAX)
 888                         t1 -= elapsed;
 889
 890                 if (t2 != UINT32_MAX)
 891                         t2 -= elapsed;
 892
 893                 if (t3 != UINT32_MAX)
 894                         t3 -= elapsed;
 895
 896                 if (t1 < 0)
 897                         t1 = 0;
 898
 899                 if (t2 < 0)
 900                         t2 = 0;
 901
 902                 if (t3 < 0)
 903                         t3 = 0;
 904         }
 905
 906         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 907                 // Delete NA and PD we have in the state from the Advert
 908                 odhcp6c_clear_state(STATE_IA_NA);
 909                 odhcp6c_clear_state(STATE_IA_PD);
 910         }
 911
 912         if (opt) {
 913                 odhcp6c_clear_state(STATE_DNS);
 914                 odhcp6c_clear_state(STATE_SEARCH);
 915                 odhcp6c_clear_state(STATE_SNTP_IP);
 916                 odhcp6c_clear_state(STATE_NTP_IP);
 917                 odhcp6c_clear_state(STATE_NTP_FQDN);
 918                 odhcp6c_clear_state(STATE_SIP_IP);
 919                 odhcp6c_clear_state(STATE_SIP_FQDN);
 920                 odhcp6c_clear_state(STATE_AFTR_NAME);
 921                 odhcp6c_clear_state(STATE_CER);
 922                 odhcp6c_clear_state(STATE_S46_MAPT);
 923                 odhcp6c_clear_state(STATE_S46_MAPE);
 924                 odhcp6c_clear_state(STATE_S46_LW);
 925                 odhcp6c_clear_state(STATE_PASSTHRU);
 926         }
 927
 928         // Parse and find all matching IAs
 929         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 930                 bool passthru = true;
 931
 932                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 933                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 934                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 935
 936                         // Test ID
 937                         if (ia_hdr->iaid != 1 && otype == DHCPV6_OPT_IA_NA)
 938                                 continue;
 939
 940                         uint16_t code = DHCPV6_Success;
 941                         uint16_t stype, slen;
 942                         uint8_t *sdata;
 943                         // Get and handle status code
 944                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 945                                         stype, slen, sdata) {
 946                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 947                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 948                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 949
 950                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 951
 952                                         if (code == DHCPV6_Success)
 953                                                 continue;
 954
 955                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 956                                                 code, mdata, mlen, handled_status_codes, &ret);
 957
 958
 959                                         if (ret > 0)
 960                                                 return ret;
 961                                         break;
 962                                 }
 963                         }
 964
 965                         if (code != DHCPV6_Success)
 966                                 continue;
 967
 968                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 969                         passthru = false;
 970                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 971                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 972                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 973                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 974
 975                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 976                         passthru = false;
 977                 }
 978                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 979                         if (olen % 16 == 0)
 980                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 981                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 982                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 983                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 984                         if (olen % 16 == 0)
 985                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 986                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 987                         uint16_t stype, slen;
 988                         uint8_t *sdata;
 989                         // Test status and bail if error
 990                         dhcpv6_for_each_option(odata, odata + olen,
 991                                         stype, slen, sdata) {
 992                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 993                                                 stype == NTP_SRV_ADDR))
 994                                         odhcp6c_add_state(STATE_NTP_IP,
 995                                                         sdata, slen);
 996                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 997                                         odhcp6c_add_state(STATE_NTP_FQDN,
 998                                                         sdata, slen);
 999                         }
1000                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1001                         if (olen == 16)
1002                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1003                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
1004                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1005                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1006                         refresh = ntohl(*((uint32_t*)odata));
1007                         passthru = false;
1008                 } else if (otype == DHCPV6_OPT_AUTH) {
1009                         if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1010                                 struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1011                                 if (r->protocol == 3 && r->algorithm == 1 &&
1012                                                 r->reconf_type == 1)
1013                                         memcpy(reconf_key, r->key, sizeof(r->key));
1014                         }
1015                         passthru = false;
1016                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1017                         size_t cur_len;
1018                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1019                         if (cur_len == 0)
1020                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1021                         passthru = false;
1022                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1023                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1024                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1025                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1026                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1027                         passthru = false;
1028                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1029                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1030                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1031                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1032                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1033                         passthru = false;
1034 #ifdef EXT_CER_ID
1035                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1036                                 sizeof(struct dhcpv6_cer_id)) {
1037                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1038                         struct in6_addr any = IN6ADDR_ANY_INIT;
1039                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1040                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1041                         passthru = false;
1042 #endif
1043 #ifdef EXT_S46
1044                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1045                         odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1046                         passthru = false;
1047                 } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1048                         size_t mape_len;
1049                         odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1050                         if (mape_len == 0)
1051                                 odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1052                         passthru = false;
1053                 } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1054                         odhcp6c_add_state(STATE_S46_LW, odata, olen);
1055                         passthru = false;
1056 #endif
1057                 } else if (otype == DHCPV6_OPT_CLIENTID ||
1058                                 otype == DHCPV6_OPT_SERVERID ||
1059                                 otype == DHCPV6_OPT_IA_TA ||
1060                                 otype == DHCPV6_OPT_PREF ||
1061                                 otype == DHCPV6_OPT_UNICAST ||
1062                                 otype == DHCPV6_OPT_FQDN) {
1063                         passthru = false;
1064                 } else {
1065                         odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1066                 }
1067
1068                 if (passthru)
1069                         odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1070         }
1071
1072         if (orig != DHCPV6_MSG_INFO_REQ) {
1073                 // Update refresh timers if no fatal status code was received
1074                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1075                         switch (orig) {
1076                         case DHCPV6_MSG_RENEW:
1077                                 // Send further renews if T1 is not set
1078                                 if (!t1)
1079                                         ret = -1;
1080                                 break;
1081                         case DHCPV6_MSG_REBIND:
1082                                 // Send further rebinds if T1 and T2 is not set
1083                                 if (!t1 && !t2)
1084                                         ret = -1;
1085                                 break;
1086
1087                         case DHCPV6_MSG_REQUEST:
1088                                 // All server candidates can be cleared if not yet bound
1089                                 if (!odhcp6c_is_bound())
1090                                         dhcpv6_clear_all_server_cand();
1091
1092                         default :
1093                                 break;
1094                         }
1095                 }
1096         }
1097         else if (ret > 0) {
1098                 // All server candidates can be cleared if not yet bound
1099                 if (!odhcp6c_is_bound())
1100                         dhcpv6_clear_all_server_cand();
1101
1102                 t1 = refresh;
1103         }
1104
1105         return ret;
1106 }
1107
1108
1109 static int dhcpv6_parse_ia(void *opt, void *end)
1110 {
1111         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1112         int parsed_ia = 0;
1113         uint32_t t1, t2;
1114         uint16_t otype, olen;
1115         uint8_t *odata;
1116
1117         t1 = ntohl(ia_hdr->t1);
1118         t2 = ntohl(ia_hdr->t2);
1119
1120         if (t1 > t2)
1121                 return 0;
1122
1123         // Update address IA
1124         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1125                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1126                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1127
1128                 entry.iaid = ia_hdr->iaid;
1129
1130                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1131                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1132                         if (olen + 4U < sizeof(*prefix))
1133                                 continue;
1134
1135                         entry.valid = ntohl(prefix->valid);
1136                         entry.preferred = ntohl(prefix->preferred);
1137
1138                         if (entry.preferred > entry.valid)
1139                                 continue;
1140
1141                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1142                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1143                         if (entry.t1 > entry.t2)
1144                                 entry.t1 = entry.t2;
1145
1146                         entry.length = prefix->prefix;
1147                         entry.target = prefix->addr;
1148                         uint16_t stype, slen;
1149                         uint8_t *sdata;
1150
1151 #ifdef EXT_PREFIX_CLASS
1152                         // Find prefix class, if any
1153                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1154                                         stype, slen, sdata)
1155                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1156                                         entry.class = sdata[0] << 8 | sdata[1];
1157 #endif
1158
1159                         // Parse PD-exclude
1160                         bool ok = true;
1161                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1162                                         odata + olen, stype, slen, sdata) {
1163                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1164                                         continue;
1165
1166                                 uint8_t elen = sdata[0];
1167                                 if (elen > 64)
1168                                         elen = 64;
1169
1170                                 if (elen <= 32 || elen <= entry.length) {
1171                                         ok = false;
1172                                         continue;
1173                                 }
1174
1175
1176                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1177                                 if (slen <= bytes) {
1178                                         ok = false;
1179                                         continue;
1180                                 }
1181
1182                                 uint32_t exclude = 0;
1183                                 do {
1184                                         exclude = exclude << 8 | sdata[bytes];
1185                                 } while (--bytes);
1186
1187                                 exclude >>= 8 - ((elen - entry.length) % 8);
1188                                 exclude <<= 64 - elen;
1189
1190                                 // Abusing router & priority fields for exclusion
1191                                 entry.router = entry.target;
1192                                 entry.router.s6_addr32[1] |= htonl(exclude);
1193                                 entry.priority = elen;
1194                         }
1195
1196                         if (ok) {
1197                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1198                                 parsed_ia++;
1199                         }
1200
1201                         entry.priority = 0;
1202                         memset(&entry.router, 0, sizeof(entry.router));
1203                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1204                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1205                         if (olen + 4U < sizeof(*addr))
1206                                 continue;
1207
1208                         entry.preferred = ntohl(addr->preferred);
1209                         entry.valid = ntohl(addr->valid);
1210
1211                         if (entry.preferred > entry.valid)
1212                                 continue;
1213
1214                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1215                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1216                         if (entry.t1 > entry.t2)
1217                                 entry.t1 = entry.t2;
1218
1219                         entry.length = 128;
1220                         entry.target = addr->addr;
1221
1222 #ifdef EXT_PREFIX_CLASS
1223                         uint16_t stype, slen;
1224                         uint8_t *sdata;
1225                         // Find prefix class, if any
1226                         dhcpv6_for_each_option(&addr[1], odata + olen,
1227                                         stype, slen, sdata)
1228                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1229                                         entry.class = sdata[0] << 8 | sdata[1];
1230 #endif
1231
1232                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1233                         parsed_ia++;
1234                 }
1235         }
1236         return parsed_ia;
1237 }
1238
1239
1240 static int dhcpv6_calc_refresh_timers(void)
1241 {
1242         struct odhcp6c_entry *e;
1243         size_t ia_na_entries, ia_pd_entries, i;
1244         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1245
1246         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1247         ia_na_entries /= sizeof(*e);
1248         for (i = 0; i < ia_na_entries; i++) {
1249                 if (e[i].t1 < l_t1)
1250                         l_t1 = e[i].t1;
1251
1252                 if (e[i].t2 < l_t2)
1253                         l_t2 = e[i].t2;
1254
1255                 if (e[i].valid > l_t3)
1256                         l_t3 = e[i].valid;
1257         }
1258
1259         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1260         ia_pd_entries /= sizeof(*e);
1261         for (i = 0; i < ia_pd_entries; i++) {
1262                 if (e[i].t1 < l_t1)
1263                         l_t1 = e[i].t1;
1264
1265                 if (e[i].t2 < l_t2)
1266                         l_t2 = e[i].t2;
1267
1268                 if (e[i].valid > l_t3)
1269                         l_t3 = e[i].valid;
1270         }
1271
1272         if (ia_pd_entries || ia_na_entries) {
1273                 t1 = l_t1;
1274                 t2 = l_t2;
1275                 t3 = l_t3;
1276         } else {
1277                 t1 = 600;
1278         }
1279
1280         return (int)(ia_pd_entries + ia_na_entries);
1281 }
1282
1283
1284 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1285                 const void *status_msg, const int len)
1286 {
1287         uint8_t buf[len + 3];
1288
1289         memset(buf, 0, sizeof(buf));
1290         if (len) {
1291                 buf[0] = '(';
1292                 memcpy(&buf[1], status_msg, len);
1293                 buf[len + 1] = ')';
1294         }
1295
1296         syslog(LOG_WARNING, "Server returned %s status %i %s",
1297                 scope, code, buf);
1298 }
1299
1300
1301 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1302                 const uint16_t code, const void *status_msg, const int len,
1303                 int *ret)
1304 {
1305         dhcpv6_log_status_code(code, "message", status_msg, len);
1306
1307         switch (code) {
1308         case DHCPV6_UnspecFail:
1309                 // Generic failure
1310                 *ret = 0;
1311                 break;
1312
1313         case DHCPV6_UseMulticast:
1314                 // TODO handle multicast status code
1315                 break;
1316
1317         case DHCPV6_NoAddrsAvail:
1318         case DHCPV6_NoPrefixAvail:
1319                 if (orig == DHCPV6_MSG_REQUEST)
1320                         *ret = 0; // Failure
1321                 break;
1322
1323         default:
1324                 break;
1325         }
1326 }
1327
1328
1329 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1330                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1331                 const void *status_msg, const int len,
1332                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1333 {
1334         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1335                 "IA_NA" : "IA_PD", status_msg, len);
1336
1337         switch (code) {
1338         case DHCPV6_NoBinding:
1339                 switch (orig) {
1340                 case DHCPV6_MSG_RENEW:
1341                 case DHCPV6_MSG_REBIND:
1342                         if ((*ret > 0) && !handled_status_codes[code])
1343                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1344                         break;
1345
1346                 default:
1347                         break;
1348                 }
1349                 break;
1350
1351         case DHCPV6_NoAddrsAvail:
1352         case DHCPV6_NoPrefixAvail:
1353                 switch (orig) {
1354                 case DHCPV6_MSG_REQUEST:
1355                         if (*ret != 0)
1356                                 *ret = 0;
1357                         break;
1358                 default:
1359                         break;
1360                 }
1361                 break;
1362
1363         case DHCPV6_NotOnLink:
1364                 // TODO handle not onlink in case of confirm
1365                 break;
1366
1367         default:
1368                 break;
1369         }
1370 }
1371
1372 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1373 {
1374         size_t cand_len, i;
1375         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1376
1377         // Remove identical duid server candidate
1378         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1379                 if (cand->duid_len == c[i].duid_len &&
1380                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1381                         free(c[i].ia_na);
1382                         free(c[i].ia_pd);
1383                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1384                         break;
1385                 }
1386         }
1387
1388         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1389                 i < cand_len / sizeof(*c); ++i) {
1390                 if (c[i].preference < cand->preference)
1391                         break;
1392         }
1393
1394         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1395 }
1396
1397 static void dhcpv6_clear_all_server_cand(void)
1398 {
1399         size_t cand_len, i;
1400         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1401
1402         // Server candidates need deep delete for IA_NA/IA_PD
1403         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1404                 free(c[i].ia_na);
1405                 free(c[i].ia_pd);
1406         }
1407         odhcp6c_clear_state(STATE_SERVER_CAND);
1408 }
1409
1410 int dhcpv6_promote_server_cand(void)
1411 {
1412         size_t cand_len;
1413         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1414         uint16_t hdr[2];
1415         int ret = DHCPV6_STATELESS;
1416
1417         // Clear lingering candidate state info
1418         odhcp6c_clear_state(STATE_SERVER_ID);
1419         odhcp6c_clear_state(STATE_IA_NA);
1420         odhcp6c_clear_state(STATE_IA_PD);
1421
1422         if (!cand_len)
1423                 return -1;
1424
1425         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1426                 na_mode = IA_MODE_NONE;
1427
1428                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1429                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1430
1431                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1432         }
1433
1434         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1435         hdr[1] = htons(cand->duid_len);
1436         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1437         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1438         accept_reconfig = cand->wants_reconfigure;
1439         if (cand->ia_na_len) {
1440                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1441                 free(cand->ia_na);
1442                 if (na_mode != IA_MODE_NONE)
1443                         ret = DHCPV6_STATEFUL;
1444         }
1445         if (cand->ia_pd_len) {
1446                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1447                 free(cand->ia_pd);
1448                 if (request_prefix)
1449                         ret = DHCPV6_STATEFUL;
1450         }
1451
1452         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1453         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1454
1455         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1456
1457         return ret;
1458 }