src/dhcpv6.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <time.h>
  17 #include <fcntl.h>
  18 #include <errno.h>
  19 #include <inttypes.h>
  20 #include <stdlib.h>
  21 #include <signal.h>
  22 #include <limits.h>
  23 #include <resolv.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <syslog.h>
  27 #include <stdbool.h>
  28 #include <ctype.h>
  29 #include <sys/time.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/socket.h>
  32 #include <arpa/inet.h>
  33 #include <netinet/in.h>
  34
  35 #include <net/if.h>
  36 #include <net/ethernet.h>
  37
  38 #include "odhcp6c.h"
  39 #ifdef USE_LIBUBOX
  40 #include <libubox/md5.h>
  41 #else
  42 #include "md5.h"
  43 #endif
  44
  45
  46 #define ALL_DHCPV6_RELAYS {{{0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
  47                 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02}}}
  48 #define DHCPV6_CLIENT_PORT 546
  49 #define DHCPV6_SERVER_PORT 547
  50 #define DHCPV6_DUID_LLADDR 3
  51 #define DHCPV6_REQ_DELAY 1
  52
  53 #define DHCPV6_SOL_MAX_RT_MIN 60
  54 #define DHCPV6_SOL_MAX_RT_MAX 86400
  55 #define DHCPV6_INF_MAX_RT_MIN 60
  56 #define DHCPV6_INF_MAX_RT_MAX 86400
  57
  58 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
  59                 const uint8_t transaction[3], enum dhcpv6_msg type,
  60                 const struct in6_addr *daddr);
  61
  62 static unsigned int dhcpv6_parse_ia(void *opt, void *end);
  63
  64 static int dhcpv6_calc_refresh_timers(void);
  65 static void dhcpv6_handle_status_code(_unused const enum dhcpv6_msg orig,
  66                 const uint16_t code, const void *status_msg, const int len,
  67                 int *ret);
  68 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
  69                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
  70                 const void *status_msg, const int len,
  71                 bool handled_status_codes[_DHCPV6_Status_Max],
  72                 int *ret);
  73 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand);
  74 static void dhcpv6_clear_all_server_cand(void);
  75
  76 static reply_handler dhcpv6_handle_reply;
  77 static reply_handler dhcpv6_handle_advert;
  78 static reply_handler dhcpv6_handle_rebind_reply;
  79 static reply_handler dhcpv6_handle_reconfigure;
  80 static int dhcpv6_commit_advert(void);
  81
  82 // RFC 3315 - 5.5 Timeout and Delay values
  83 static struct dhcpv6_retx dhcpv6_retx[_DHCPV6_MSG_MAX] = {
  84         [DHCPV6_MSG_UNKNOWN] = {false, 1, 120, 0, "<POLL>",
  85                         dhcpv6_handle_reconfigure, NULL},
  86         [DHCPV6_MSG_SOLICIT] = {true, 1, DHCPV6_SOL_MAX_RT, 0, "SOLICIT",
  87                         dhcpv6_handle_advert, dhcpv6_commit_advert},
  88         [DHCPV6_MSG_REQUEST] = {true, 1, DHCPV6_REQ_MAX_RT, 10, "REQUEST",
  89                         dhcpv6_handle_reply, NULL},
  90         [DHCPV6_MSG_RENEW] = {false, 10, DHCPV6_REN_MAX_RT, 0, "RENEW",
  91                         dhcpv6_handle_reply, NULL},
  92         [DHCPV6_MSG_REBIND] = {false, 10, DHCPV6_REB_MAX_RT, 0, "REBIND",
  93                         dhcpv6_handle_rebind_reply, NULL},
  94         [DHCPV6_MSG_RELEASE] = {false, 1, 0, 5, "RELEASE", NULL, NULL},
  95         [DHCPV6_MSG_DECLINE] = {false, 1, 0, 5, "DECLINE", NULL, NULL},
  96         [DHCPV6_MSG_INFO_REQ] = {true, 1, DHCPV6_INF_MAX_RT, 0, "INFOREQ",
  97                         dhcpv6_handle_reply, NULL},
  98 };
  99
 100 // Sockets
 101 static int sock = -1;
 102 static int ifindex = -1;
 103 static int64_t t1 = 0, t2 = 0, t3 = 0;
 104
 105 // IA states
 106 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 107 static bool accept_reconfig = false;
 108 // Server unicast address
 109 static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
 110
 111 // Reconfigure key
 112 static uint8_t reconf_key[16];
 113
 114 // client options
 115 static unsigned int client_options = 0;
 116
 117 static uint32_t ntohl_unaligned(const uint8_t *data)
 118 {
 119         uint32_t buf;
 120
 121         memcpy(&buf, data, sizeof(buf));
 122         return ntohl(buf);
 123 }
 124
 125 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 126 {
 127         client_options = options;
 128         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_timeout;
 129
 130         sock = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 131         if (sock < 0)
 132                 goto failure;
 133
 134         // Detect interface
 135         struct ifreq ifr;
 136         memset(&ifr, 0, sizeof(ifr));
 137         strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
 138         if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0)
 139                 goto failure;
 140
 141         ifindex = ifr.ifr_ifindex;
 142
 143         // Create client DUID
 144         size_t client_id_len;
 145         odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 146         if (client_id_len == 0) {
 147                 uint8_t duid[14] = {0, DHCPV6_OPT_CLIENTID, 0, 10, 0,
 148                                 DHCPV6_DUID_LLADDR, 0, 1};
 149
 150                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) >= 0)
 151                         memcpy(&duid[8], ifr.ifr_hwaddr.sa_data, ETHER_ADDR_LEN);
 152
 153                 uint8_t zero[ETHER_ADDR_LEN] = {0, 0, 0, 0, 0, 0};
 154                 struct ifreq ifs[100], *ifp, *ifend;
 155                 struct ifconf ifc;
 156                 ifc.ifc_req = ifs;
 157                 ifc.ifc_len = sizeof(ifs);
 158
 159                 if (!memcmp(&duid[8], zero, ETHER_ADDR_LEN) &&
 160                                 ioctl(sock, SIOCGIFCONF, &ifc) >= 0) {
 161                         // If our interface doesn't have an address...
 162                         ifend = ifs + (ifc.ifc_len / sizeof(struct ifreq));
 163                         for (ifp = ifc.ifc_req; ifp < ifend &&
 164                                         !memcmp(&duid[8], zero, ETHER_ADDR_LEN); ifp++) {
 165                                 memcpy(ifr.ifr_name, ifp->ifr_name,
 166                                                 sizeof(ifr.ifr_name));
 167                                 if (ioctl(sock, SIOCGIFHWADDR, &ifr) < 0)
 168                                         continue;
 169
 170                                 memcpy(&duid[8], ifr.ifr_hwaddr.sa_data,
 171                                                 ETHER_ADDR_LEN);
 172                         }
 173                 }
 174
 175                 odhcp6c_add_state(STATE_CLIENT_ID, duid, sizeof(duid));
 176         }
 177
 178         // Create ORO
 179         if (!(client_options & DHCPV6_STRICT_OPTIONS)) {
 180                 uint16_t oro[] = {
 181                         htons(DHCPV6_OPT_SIP_SERVER_D),
 182                         htons(DHCPV6_OPT_SIP_SERVER_A),
 183                         htons(DHCPV6_OPT_DNS_SERVERS),
 184                         htons(DHCPV6_OPT_DNS_DOMAIN),
 185                         htons(DHCPV6_OPT_SNTP_SERVERS),
 186                         htons(DHCPV6_OPT_NTP_SERVER),
 187                         htons(DHCPV6_OPT_AFTR_NAME),
 188                         htons(DHCPV6_OPT_PD_EXCLUDE),
 189                         htons(DHCPV6_OPT_SOL_MAX_RT),
 190                         htons(DHCPV6_OPT_INF_MAX_RT),
 191 #ifdef EXT_CER_ID
 192                         htons(DHCPV6_OPT_CER_ID),
 193 #endif
 194                         htons(DHCPV6_OPT_S46_CONT_MAPE),
 195                         htons(DHCPV6_OPT_S46_CONT_MAPT),
 196                         htons(DHCPV6_OPT_S46_CONT_LW),
 197                 };
 198                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 199         }
 200         // Required oro
 201         uint16_t req_oro[] = {
 202                 htons(DHCPV6_OPT_INF_MAX_RT),
 203                 htons(DHCPV6_OPT_SOL_MAX_RT),
 204                 htons(DHCPV6_OPT_INFO_REFRESH),
 205         };
 206         odhcp6c_add_state(STATE_ORO, req_oro, sizeof(req_oro));
 207
 208         // Configure IPv6-options
 209         int val = 1;
 210         if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val)) < 0)
 211                 goto failure;
 212
 213         if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)) < 0)
 214                 goto failure;
 215
 216         if (setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val)) < 0)
 217                 goto failure;
 218
 219         if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname)) < 0)
 220                 goto failure;
 221
 222         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 223                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 224
 225         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 226                 goto failure;
 227
 228         return 0;
 229
 230 failure:
 231         if (sock >= 0)
 232                 close(sock);
 233
 234         return -1;
 235 }
 236
 237 enum {
 238         IOV_HDR=0,
 239         IOV_ORO,
 240         IOV_CL_ID,
 241         IOV_SRV_ID,
 242         IOV_OPTS,
 243         IOV_RECONF_ACCEPT,
 244         IOV_FQDN,
 245         IOV_HDR_IA_NA,
 246         IOV_IA_NA,
 247         IOV_IA_PD,
 248         IOV_TOTAL
 249 };
 250
 251 int dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 252 {
 253         int mode = DHCPV6_UNKNOWN;
 254
 255         na_mode = na;
 256         pd_mode = pd;
 257
 258         if (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE)
 259                 mode = DHCPV6_STATELESS;
 260         else if (na_mode == IA_MODE_FORCE || pd_mode == IA_MODE_FORCE)
 261                 mode = DHCPV6_STATEFUL;
 262
 263         return mode;
 264 }
 265
 266 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 267 {
 268         // Build FQDN
 269         char fqdn_buf[256];
 270         gethostname(fqdn_buf, sizeof(fqdn_buf));
 271         struct {
 272                 uint16_t type;
 273                 uint16_t len;
 274                 uint8_t flags;
 275                 uint8_t data[256];
 276         } fqdn;
 277         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 278                         sizeof(fqdn.data), NULL, NULL);
 279         fqdn.type = htons(DHCPV6_OPT_FQDN);
 280         fqdn.len = htons(fqdn_len - 4);
 281         fqdn.flags = 0;
 282
 283         // Build Client ID
 284         size_t cl_id_len;
 285         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 286
 287         // Get Server ID
 288         size_t srv_id_len;
 289         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 290
 291         // Build IA_PDs
 292         size_t ia_pd_entries = 0, ia_pd_len = 0;
 293         uint8_t *ia_pd;
 294
 295         if (type == DHCPV6_MSG_SOLICIT) {
 296                 odhcp6c_clear_state(STATE_IA_PD);
 297                 size_t n_prefixes;
 298                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 299                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 300
 301                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 302
 303                 for (size_t i = 0; i < n_prefixes; i++) {
 304                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 305                                 htons(DHCPV6_OPT_IA_PD),
 306                                 htons(sizeof(hdr_ia_pd) - 4 +
 307                                       sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
 308                                 request_prefixes[i].iaid, 0, 0
 309                         };
 310                         struct dhcpv6_ia_prefix pref = {
 311                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 312                                 .len = htons(sizeof(pref) - 4),
 313                                 .prefix = request_prefixes[i].length
 314                         };
 315                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 316                         ia_pd_len += sizeof(hdr_ia_pd);
 317                         if (request_prefixes[i].length) {
 318                                 memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 319                                 ia_pd_len += sizeof(pref);
 320                         }
 321                 }
 322         } else {
 323                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 324                 ia_pd_entries /= sizeof(*e);
 325
 326                 // we're too lazy to count our distinct IAIDs,
 327                 // so just allocate maximally needed space
 328                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 329                                         sizeof(struct dhcpv6_ia_hdr)));
 330
 331                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 332                         uint32_t iaid = e[i].iaid;
 333
 334                         // check if this is an unprocessed IAID and skip if not.
 335                         int new_iaid = 1;
 336                         for (int j = i-1; j >= 0; j--) {
 337                                 if (e[j].iaid == iaid) {
 338                                         new_iaid = 0;
 339                                         break;
 340                                 }
 341                         }
 342
 343                         if (!new_iaid)
 344                                 continue;
 345
 346                         // construct header
 347                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 348                                 htons(DHCPV6_OPT_IA_PD),
 349                                 htons(sizeof(hdr_ia_pd) - 4),
 350                                 iaid, 0, 0
 351                         };
 352
 353                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 354                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 355                         ia_pd_len += sizeof(hdr_ia_pd);
 356
 357                         for (size_t j = i; j < ia_pd_entries; j++) {
 358                                 if (e[j].iaid != iaid)
 359                                         continue;
 360
 361                                 uint8_t ex_len = 0;
 362                                 if (e[j].priority > 0)
 363                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 364
 365                                 struct dhcpv6_ia_prefix p = {
 366                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 367                                         .len = htons(sizeof(p) - 4U + ex_len),
 368                                         .prefix = e[j].length,
 369                                         .addr = e[j].target
 370                                 };
 371
 372                                 if (type == DHCPV6_MSG_REQUEST) {
 373                                         p.preferred = htonl(e[j].preferred);
 374                                         p.valid = htonl(e[j].valid);
 375                                 }
 376
 377                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 378                                 ia_pd_len += sizeof(p);
 379
 380                                 if (ex_len) {
 381                                         ia_pd[ia_pd_len++] = 0;
 382                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 383                                         ia_pd[ia_pd_len++] = 0;
 384                                         ia_pd[ia_pd_len++] = ex_len - 4;
 385                                         ia_pd[ia_pd_len++] = e[j].priority;
 386
 387                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 388                                         excl >>= (64 - e[j].priority);
 389                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 390
 391                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 392                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 393                                         ia_pd_len += ex_len - 5;
 394                                 }
 395
 396                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 397                         }
 398                 }
 399         }
 400
 401         // Build IA_NAs
 402         size_t ia_na_entries, ia_na_len = 0;
 403         void *ia_na = NULL;
 404         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 405         ia_na_entries /= sizeof(*e);
 406
 407         struct dhcpv6_ia_hdr hdr_ia_na = {
 408                 htons(DHCPV6_OPT_IA_NA),
 409                 htons(sizeof(hdr_ia_na) - 4),
 410                 htonl(1), 0, 0
 411         };
 412
 413         struct dhcpv6_ia_addr pa[ia_na_entries];
 414         for (size_t i = 0; i < ia_na_entries; ++i) {
 415                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 416                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 417                 pa[i].addr = e[i].target;
 418
 419                 if (type == DHCPV6_MSG_REQUEST) {
 420                         pa[i].preferred = htonl(e[i].preferred);
 421                         pa[i].valid = htonl(e[i].valid);
 422                 } else {
 423                         pa[i].preferred = 0;
 424                         pa[i].valid = 0;
 425                 }
 426         }
 427
 428         ia_na = pa;
 429         ia_na_len = sizeof(pa);
 430         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 431
 432         // Reconfigure Accept
 433         struct {
 434                 uint16_t type;
 435                 uint16_t length;
 436         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 437
 438         // Option list
 439         size_t opts_len;
 440         void *opts = odhcp6c_get_state(STATE_OPTS, &opts_len);
 441
 442         // Option Request List
 443         size_t oro_entries, oro_len = 0;
 444         uint16_t *oro, *s_oro = odhcp6c_get_state(STATE_ORO, &oro_entries);
 445
 446         oro_entries /= sizeof(*s_oro);
 447         oro = alloca(oro_entries * sizeof(*oro));
 448
 449         for (size_t i = 0; i < oro_entries; i++) {
 450                 struct odhcp6c_opt *opt = odhcp6c_find_opt(htons(s_oro[i]));
 451
 452                 if (opt) {
 453                         if (!(opt->flags & OPT_ORO))
 454                                 continue;
 455
 456                         if ((opt->flags & OPT_ORO_SOLICIT) && type != DHCPV6_MSG_SOLICIT)
 457                                 continue;
 458
 459                         if ((opt->flags & OPT_ORO_STATELESS) && type != DHCPV6_MSG_INFO_REQ)
 460                                 continue;
 461
 462                         if ((opt->flags & OPT_ORO_STATEFUL) && type == DHCPV6_MSG_INFO_REQ)
 463                                 continue;
 464                 }
 465
 466                 oro[oro_len++] = s_oro[i];
 467         }
 468         oro_len *= sizeof(*oro);
 469
 470         // Prepare Header
 471         struct {
 472                 uint8_t type;
 473                 uint8_t trid[3];
 474                 uint16_t elapsed_type;
 475                 uint16_t elapsed_len;
 476                 uint16_t elapsed_value;
 477                 uint16_t oro_type;
 478                 uint16_t oro_len;
 479         } hdr = {
 480                 type, {trid[0], trid[1], trid[2]},
 481                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 482                         htons((ecs > 0xffff) ? 0xffff : ecs),
 483                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 484         };
 485
 486         struct iovec iov[IOV_TOTAL] = {
 487                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 488                 [IOV_ORO] = {oro, oro_len},
 489                 [IOV_CL_ID] = {cl_id, cl_id_len},
 490                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 491                 [IOV_OPTS] = { opts, opts_len },
 492                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 493                 [IOV_FQDN] = {&fqdn, fqdn_len},
 494                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 495                 [IOV_IA_NA] = {ia_na, ia_na_len},
 496                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 497         };
 498
 499         size_t cnt = IOV_TOTAL;
 500         if (type == DHCPV6_MSG_INFO_REQ)
 501                 cnt = IOV_HDR_IA_NA;
 502
 503         // Disable IAs if not used
 504         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 505                 iov[IOV_HDR_IA_NA].iov_len = 0;
 506
 507         if (na_mode == IA_MODE_NONE)
 508                 iov[IOV_HDR_IA_NA].iov_len = 0;
 509
 510         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 511                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 512                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 513
 514         if (!(client_options & DHCPV6_CLIENT_FQDN))
 515                 iov[IOV_FQDN].iov_len = 0;
 516
 517         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 518                 0, ALL_DHCPV6_RELAYS, ifindex};
 519         struct msghdr msg = {.msg_name = &srv, .msg_namelen = sizeof(srv),
 520                         .msg_iov = iov, .msg_iovlen = cnt};
 521
 522         switch (type) {
 523         case DHCPV6_MSG_REQUEST:
 524         case DHCPV6_MSG_RENEW:
 525         case DHCPV6_MSG_RELEASE:
 526         case DHCPV6_MSG_DECLINE:
 527                 if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
 528                         odhcp6c_addr_in_scope(&server_addr)) {
 529                         srv.sin6_addr = server_addr;
 530                         if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
 531                                 srv.sin6_scope_id = 0;
 532                 }
 533                 break;
 534         default:
 535                 break;
 536         }
 537
 538         if (sendmsg(sock, &msg, 0) < 0) {
 539                 char in6_str[INET6_ADDRSTRLEN];
 540
 541                 syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
 542                         inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
 543                                 in6_str, sizeof(in6_str)), strerror(errno));
 544         }
 545 }
 546
 547 static int64_t dhcpv6_rand_delay(int64_t time)
 548 {
 549         int random;
 550         odhcp6c_random(&random, sizeof(random));
 551
 552         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 553 }
 554
 555 int dhcpv6_request(enum dhcpv6_msg type)
 556 {
 557         uint8_t rc = 0;
 558         uint64_t timeout = UINT32_MAX;
 559         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 560
 561         if (retx->delay) {
 562                 struct timespec ts = {0, 0};
 563                 ts.tv_nsec = (dhcpv6_rand_delay((10000 * DHCPV6_REQ_DELAY) / 2) + (1000 * DHCPV6_REQ_DELAY) / 2) * 1000000;
 564
 565                 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 566         }
 567
 568         if (type == DHCPV6_MSG_UNKNOWN)
 569                 timeout = t1;
 570         else if (type == DHCPV6_MSG_RENEW)
 571                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 572         else if (type == DHCPV6_MSG_REBIND)
 573                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 574
 575         if (timeout == 0)
 576                 return -1;
 577
 578         syslog(LOG_NOTICE, "Starting %s transaction (timeout %"PRIu64"s, max rc %d)",
 579                         retx->name, timeout, retx->max_rc);
 580
 581         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 582
 583         // Generate transaction ID
 584         uint8_t trid[3] = {0, 0, 0};
 585         if (type != DHCPV6_MSG_UNKNOWN)
 586                 odhcp6c_random(trid, sizeof(trid));
 587
 588         ssize_t len = -1;
 589         int64_t rto = 0;
 590
 591         do {
 592                 if (rto == 0) {
 593                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 594
 595                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 596                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 597                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 598
 599                         rto = (retx->init_timeo * 1000 + delay);
 600                 } else
 601                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 602
 603                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 604                         rto = retx->max_timeo * 1000 +
 605                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 606
 607                 // Calculate end for this round and elapsed time
 608                 uint64_t round_end = round_start + rto;
 609                 elapsed = round_start - start;
 610
 611                 // Don't wait too long if timeout differs from infinite
 612                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 613                         round_end = timeout * 1000 + start;
 614
 615                 // Built and send package
 616                 switch (type) {
 617                 case DHCPV6_MSG_UNKNOWN:
 618                         break;
 619                 default:
 620                         syslog(LOG_NOTICE, "Send %s message (elapsed %"PRIu64"ms, rc %d)",
 621                                         retx->name, elapsed, rc);
 622                         // Fall through
 623                 case DHCPV6_MSG_SOLICIT:
 624                 case DHCPV6_MSG_INFO_REQ:
 625                         dhcpv6_send(type, trid, elapsed / 10);
 626                         rc++;
 627                 }
 628
 629                 // Receive rounds
 630                 for (; len < 0 && (round_start < round_end);
 631                                 round_start = odhcp6c_get_milli_time()) {
 632                         uint8_t buf[1536];
 633                         union {
 634                                 struct cmsghdr hdr;
 635                                 uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 636                         } cmsg_buf;
 637                         struct iovec iov = {buf, sizeof(buf)};
 638                         struct sockaddr_in6 addr;
 639                         struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
 640                                         .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf.buf,
 641                                         .msg_controllen = sizeof(cmsg_buf)};
 642                         struct in6_pktinfo *pktinfo = NULL;
 643
 644                         // Check for pending signal
 645                         if (odhcp6c_signal_process())
 646                                 return -1;
 647
 648                         // Set timeout for receiving
 649                         uint64_t t = round_end - round_start;
 650                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 651                         if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 652                                         &tv, sizeof(tv)) < 0)
 653                                 syslog(LOG_ERR, "setsockopt SO_RCVTIMEO failed (%s)",
 654                                                 strerror(errno));
 655
 656                         // Receive cycle
 657                         len = recvmsg(sock, &msg, 0);
 658                         if (len < 0)
 659                                 continue;
 660
 661                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 662                                 ch = CMSG_NXTHDR(&msg, ch)) {
 663                                 if (ch->cmsg_level == SOL_IPV6 &&
 664                                         ch->cmsg_type == IPV6_PKTINFO) {
 665                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 666                                         break;
 667                                 }
 668                         }
 669
 670                         if (pktinfo == NULL) {
 671                                 len = -1;
 672                                 continue;
 673                         }
 674
 675                         if (!dhcpv6_response_is_valid(buf, len, trid,
 676                                                         type, &pktinfo->ipi6_addr)) {
 677                                 len = -1;
 678                                 continue;
 679                         }
 680
 681                         uint8_t *opt = &buf[4];
 682                         uint8_t *opt_end = opt + len - 4;
 683
 684                         round_start = odhcp6c_get_milli_time();
 685                         elapsed = round_start - start;
 686                         syslog(LOG_NOTICE, "Got a valid reply after %"PRIu64"ms",
 687                                         elapsed);
 688
 689                         if (retx->handler_reply)
 690                                 len = retx->handler_reply(type, rc, opt, opt_end, &addr);
 691
 692                         if (len > 0 && round_end - round_start > 1000)
 693                                 round_end = 1000 + round_start;
 694                 }
 695
 696                 // Allow
 697                 if (retx->handler_finish)
 698                         len = retx->handler_finish();
 699         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 700                         (!retx->max_rc || rc < retx->max_rc));
 701         return len;
 702 }
 703
 704 // Message validation checks according to RFC3315 chapter 15
 705 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 706                 const uint8_t transaction[3], enum dhcpv6_msg type,
 707                 const struct in6_addr *daddr)
 708 {
 709         const struct dhcpv6_header *rep = buf;
 710         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 711                         transaction, sizeof(rep->tr_id)))
 712                 return false; // Invalid reply
 713
 714         if (type == DHCPV6_MSG_SOLICIT) {
 715                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 716                                 rep->msg_type != DHCPV6_MSG_REPLY)
 717                         return false;
 718
 719         } else if (type == DHCPV6_MSG_UNKNOWN) {
 720                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 721                         return false;
 722
 723         } else if (rep->msg_type != DHCPV6_MSG_REPLY)
 724                 return false;
 725
 726         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 727                 rcmsg = DHCPV6_MSG_UNKNOWN;
 728         uint16_t otype, olen = UINT16_MAX;
 729         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 730                 ia_present = false, options_valid = true;
 731
 732         size_t client_id_len, server_id_len;
 733         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 734         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 735
 736         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 737                 if (otype == DHCPV6_OPT_CLIENTID) {
 738                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 739                                         &odata[-4], client_id, client_id_len);
 740                 } else if (otype == DHCPV6_OPT_SERVERID) {
 741                         if (server_id_len)
 742                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 743                                                 &odata[-4], server_id, server_id_len);
 744                         else
 745                                 serverid_ok = true;
 746                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 747                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 748                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 749                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 750                                 continue;
 751
 752                         md5_ctx_t md5;
 753                         uint8_t serverhash[16], secretbytes[64];
 754                         uint32_t hash[4];
 755                         memcpy(serverhash, r->key, sizeof(serverhash));
 756                         memset(r->key, 0, sizeof(r->key));
 757
 758                         memset(secretbytes, 0, sizeof(secretbytes));
 759                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 760
 761                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 762                                 secretbytes[i] ^= 0x36;
 763
 764                         md5_begin(&md5);
 765                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 766                         md5_hash(buf, len, &md5);
 767                         md5_end(hash, &md5);
 768
 769                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 770                                 secretbytes[i] ^= 0x36;
 771                                 secretbytes[i] ^= 0x5c;
 772                         }
 773
 774                         md5_begin(&md5);
 775                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 776                         md5_hash(hash, 16, &md5);
 777                         md5_end(hash, &md5);
 778
 779                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 780                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 781                         rcmsg = odata[0];
 782                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 783                         ia_present = true;
 784                         if (olen < -4 + sizeof(struct dhcpv6_ia_hdr))
 785                                 options_valid = false;
 786                 } else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 787                                 (otype == DHCPV6_OPT_PD_EXCLUDE))
 788                         // Options are not allowed on global level
 789                         options_valid = false;
 790         }
 791
 792         if (!options_valid || ((odata + olen) > end))
 793                 return false;
 794
 795         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 796                 return false;
 797
 798         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 799                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_REBIND && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 800                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 801                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 802                         return false;
 803         }
 804
 805         return clientid_ok && serverid_ok;
 806 }
 807
 808 int dhcpv6_poll_reconfigure(void)
 809 {
 810         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 811
 812         if (ret != -1)
 813                 ret = dhcpv6_request(ret);
 814
 815         return ret;
 816 }
 817
 818 static int dhcpv6_handle_reconfigure(enum dhcpv6_msg orig, const int rc,
 819                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 820 {
 821         uint16_t otype, olen;
 822         uint8_t *odata;
 823         int msg = -1;
 824
 825         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 826                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 827                         switch (odata[0]) {
 828                         case DHCPV6_MSG_REBIND:
 829                                 if (t2 != UINT32_MAX)
 830                                         t2 = 0;
 831                         // Fall through
 832                         case DHCPV6_MSG_RENEW:
 833                                 if (t1 != UINT32_MAX)
 834                                         t1 = 0;
 835                         // Fall through
 836                         case DHCPV6_MSG_INFO_REQ:
 837                                 msg = odata[0];
 838                                 break;
 839
 840                         default:
 841                                 break;
 842                         }
 843                 }
 844         }
 845
 846         dhcpv6_handle_reply(orig, rc, NULL, NULL, NULL);
 847
 848         return msg;
 849 }
 850
 851 // Collect all advertised servers
 852 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 853                 const void *opt, const void *end, _unused const struct sockaddr_in6 *from)
 854 {
 855         uint16_t olen, otype;
 856         uint8_t *odata, pref = 0;
 857         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 858                                         IN6ADDR_ANY_INIT, DHCPV6_SOL_MAX_RT,
 859                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 860         bool have_na = false;
 861         int have_pd = 0;
 862
 863         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 864                 if (orig == DHCPV6_MSG_SOLICIT &&
 865                                 ((otype == DHCPV6_OPT_IA_PD && pd_mode != IA_MODE_NONE) ||
 866                                  (otype == DHCPV6_OPT_IA_NA && na_mode != IA_MODE_NONE)) &&
 867                                 olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
 868                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 869                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 870                 }
 871
 872                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 873                         memcpy(cand.duid, odata, olen);
 874                         cand.duid_len = olen;
 875                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 876                                 cand.preference >= 0) {
 877                         cand.preference = pref = odata[0];
 878                 } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
 879                         if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
 880                                 cand.server_addr = *(struct in6_addr *)odata;
 881
 882                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 883                         cand.wants_reconfigure = true;
 884                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 885                         uint32_t sol_max_rt = ntohl_unaligned(odata);
 886                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 887                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 888                                 cand.sol_max_rt = sol_max_rt;
 889
 890                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 891                         uint32_t inf_max_rt = ntohl_unaligned(odata);
 892                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 893                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 894                                 cand.inf_max_rt = inf_max_rt;
 895
 896                 } else if (otype == DHCPV6_OPT_IA_PD &&
 897                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 898                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 899                         uint8_t *oend = odata + olen, *d;
 900                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 901                                 if (otype == DHCPV6_OPT_IA_PREFIX &&
 902                                                 olen >= -4 + sizeof(struct dhcpv6_ia_prefix)) {
 903                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 904                                         have_pd = p->prefix;
 905                                 }
 906                         }
 907                 } else if (otype == DHCPV6_OPT_IA_NA &&
 908                                         olen >= -4 + sizeof(struct dhcpv6_ia_hdr)) {
 909                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 910                         uint8_t *oend = odata + olen, *d;
 911
 912                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 913                                 if (otype == DHCPV6_OPT_IA_ADDR &&
 914                                                 olen >= -4 + sizeof(struct dhcpv6_ia_addr))
 915                                         have_na = true;
 916                         }
 917                 }
 918         }
 919
 920         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 921                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 922                 /*
 923                  * RFC7083 states to process the SOL_MAX_RT and
 924                  * INF_MAX_RT options even if the DHCPv6 server
 925                  * did not propose any IA_NA and/or IA_PD
 926                  */
 927                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 928                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 929                 return -1;
 930         }
 931
 932         if (na_mode != IA_MODE_NONE && !have_na) {
 933                 cand.has_noaddravail = true;
 934                 cand.preference -= 1000;
 935         }
 936
 937         if (pd_mode != IA_MODE_NONE) {
 938                 if (have_pd)
 939                         cand.preference += 2000 + (128 - have_pd);
 940                 else
 941                         cand.preference -= 2000;
 942         }
 943
 944         if (cand.duid_len > 0) {
 945                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 946                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 947                 dhcpv6_add_server_cand(&cand);
 948         }
 949
 950         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 951 }
 952
 953 static int dhcpv6_commit_advert(void)
 954 {
 955         return dhcpv6_promote_server_cand();
 956 }
 957
 958 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 959                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 960 {
 961         dhcpv6_handle_advert(orig, rc, opt, end, from);
 962         if (dhcpv6_commit_advert() < 0)
 963                 return -1;
 964
 965         return dhcpv6_handle_reply(orig, rc, opt, end, from);
 966 }
 967
 968 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 969                 const void *opt, const void *end, const struct sockaddr_in6 *from)
 970 {
 971         uint8_t *odata;
 972         uint16_t otype, olen;
 973         uint32_t refresh = 86400;
 974         int ret = 1;
 975         unsigned int updated_IAs = 0;
 976         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 977
 978         odhcp6c_expire();
 979
 980         if (orig == DHCPV6_MSG_UNKNOWN) {
 981                 static time_t last_update = 0;
 982                 time_t now = odhcp6c_get_milli_time() / 1000;
 983
 984                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 985                 last_update = now;
 986
 987                 if (t1 != UINT32_MAX)
 988                         t1 -= elapsed;
 989
 990                 if (t2 != UINT32_MAX)
 991                         t2 -= elapsed;
 992
 993                 if (t3 != UINT32_MAX)
 994                         t3 -= elapsed;
 995
 996                 if (t1 < 0)
 997                         t1 = 0;
 998
 999                 if (t2 < 0)
1000                         t2 = 0;
1001
1002                 if (t3 < 0)
1003                         t3 = 0;
1004         }
1005
1006         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
1007                 // Delete NA and PD we have in the state from the Advert
1008                 odhcp6c_clear_state(STATE_IA_NA);
1009                 odhcp6c_clear_state(STATE_IA_PD);
1010         }
1011
1012         if (opt) {
1013                 odhcp6c_clear_state(STATE_DNS);
1014                 odhcp6c_clear_state(STATE_SEARCH);
1015                 odhcp6c_clear_state(STATE_SNTP_IP);
1016                 odhcp6c_clear_state(STATE_NTP_IP);
1017                 odhcp6c_clear_state(STATE_NTP_FQDN);
1018                 odhcp6c_clear_state(STATE_SIP_IP);
1019                 odhcp6c_clear_state(STATE_SIP_FQDN);
1020                 odhcp6c_clear_state(STATE_AFTR_NAME);
1021                 odhcp6c_clear_state(STATE_CER);
1022                 odhcp6c_clear_state(STATE_S46_MAPT);
1023                 odhcp6c_clear_state(STATE_S46_MAPE);
1024                 odhcp6c_clear_state(STATE_S46_LW);
1025                 odhcp6c_clear_state(STATE_PASSTHRU);
1026                 odhcp6c_clear_state(STATE_CUSTOM_OPTS);
1027
1028                 // Parse and find all matching IAs
1029                 dhcpv6_for_each_option(opt, end, otype, olen, odata) {
1030                         struct odhcp6c_opt *dopt = odhcp6c_find_opt(otype);
1031
1032                         if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
1033                                         && olen > -4 + sizeof(struct dhcpv6_ia_hdr)) {
1034                                 struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
1035
1036                                 if ((na_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_NA) ||
1037                                         (pd_mode == IA_MODE_NONE && otype == DHCPV6_OPT_IA_PD))
1038                                         continue;
1039
1040                                 // Test ID
1041                                 if (ia_hdr->iaid != htonl(1) && otype == DHCPV6_OPT_IA_NA)
1042                                         continue;
1043
1044                                 uint16_t code = DHCPV6_Success;
1045                                 uint16_t stype, slen;
1046                                 uint8_t *sdata;
1047                                 // Get and handle status code
1048                                 dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
1049                                                 stype, slen, sdata) {
1050                                         if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
1051                                                 uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
1052                                                 uint16_t mlen = (slen > 2) ? slen - 2 : 0;
1053
1054                                                 code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
1055
1056                                                 if (code == DHCPV6_Success)
1057                                                         continue;
1058
1059                                                 dhcpv6_handle_ia_status_code(orig, ia_hdr,
1060                                                         code, mdata, mlen, handled_status_codes, &ret);
1061
1062                                                 if (ret > 0)
1063                                                         return ret;
1064
1065                                                 break;
1066                                         }
1067                                 }
1068
1069                                 if (code != DHCPV6_Success)
1070                                         continue;
1071
1072                                 updated_IAs += dhcpv6_parse_ia(ia_hdr, odata + olen);
1073                         } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
1074                                 if (!(client_options & DHCPV6_IGNORE_OPT_UNICAST))
1075                                         server_addr = *(struct in6_addr *)odata;
1076
1077                         }
1078                         else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
1079                                 uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
1080                                 uint16_t mlen = (olen > 2) ? olen - 2 : 0;
1081                                 uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
1082
1083                                 dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
1084                         } else if (otype == DHCPV6_OPT_DNS_SERVERS) {
1085                                 if (olen % 16 == 0)
1086                                         odhcp6c_add_state(STATE_DNS, odata, olen);
1087                         } else if (otype == DHCPV6_OPT_DNS_DOMAIN)
1088                                 odhcp6c_add_state(STATE_SEARCH, odata, olen);
1089                         else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
1090                                 if (olen % 16 == 0)
1091                                         odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
1092                         } else if (otype == DHCPV6_OPT_NTP_SERVER) {
1093                                 uint16_t stype, slen;
1094                                 uint8_t *sdata;
1095                                 // Test status and bail if error
1096                                 dhcpv6_for_each_option(odata, odata + olen,
1097                                                 stype, slen, sdata) {
1098                                         if (slen == 16 && (stype == NTP_MC_ADDR ||
1099                                                         stype == NTP_SRV_ADDR))
1100                                                 odhcp6c_add_state(STATE_NTP_IP,
1101                                                                 sdata, slen);
1102                                         else if (slen > 0 && stype == NTP_SRV_FQDN)
1103                                                 odhcp6c_add_state(STATE_NTP_FQDN,
1104                                                                 sdata, slen);
1105                                 }
1106                         } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
1107                                 if (olen == 16)
1108                                         odhcp6c_add_state(STATE_SIP_IP, odata, olen);
1109                         } else if (otype == DHCPV6_OPT_SIP_SERVER_D)
1110                                 odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
1111                         else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
1112                                 refresh = ntohl_unaligned(odata);
1113                         } else if (otype == DHCPV6_OPT_AUTH) {
1114                                 if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
1115                                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
1116                                         if (r->protocol == 3 && r->algorithm == 1 &&
1117                                                         r->reconf_type == 1)
1118                                                 memcpy(reconf_key, r->key, sizeof(r->key));
1119                                 }
1120                         } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1121                                 size_t cur_len;
1122                                 odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1123                                 if (cur_len == 0)
1124                                         odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1125                         } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1126                                 uint32_t sol_max_rt = ntohl_unaligned(odata);
1127                                 if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1128                                                 sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1129                                         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1130                         } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1131                                 uint32_t inf_max_rt = ntohl_unaligned(odata);
1132                                 if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1133                                                 inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1134                                         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1135         #ifdef EXT_CER_ID
1136                         } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1137                                         sizeof(struct dhcpv6_cer_id)) {
1138                                 struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1139                                 struct in6_addr any = IN6ADDR_ANY_INIT;
1140                                 if (memcmp(&cer_id->addr, &any, sizeof(any)))
1141                                         odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1142         #endif
1143                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPT) {
1144                                 odhcp6c_add_state(STATE_S46_MAPT, odata, olen);
1145                         } else if (otype == DHCPV6_OPT_S46_CONT_MAPE) {
1146                                 size_t mape_len;
1147                                 odhcp6c_get_state(STATE_S46_MAPE, &mape_len);
1148                                 if (mape_len == 0)
1149                                         odhcp6c_add_state(STATE_S46_MAPE, odata, olen);
1150                         } else if (otype == DHCPV6_OPT_S46_CONT_LW) {
1151                                 odhcp6c_add_state(STATE_S46_LW, odata, olen);
1152                         } else
1153                                 odhcp6c_add_state(STATE_CUSTOM_OPTS, &odata[-4], olen + 4);
1154
1155                         if (!dopt || !(dopt->flags & OPT_NO_PASSTHRU))
1156                                 odhcp6c_add_state(STATE_PASSTHRU, &odata[-4], olen + 4);
1157                 }
1158         }
1159
1160         switch (orig) {
1161         case DHCPV6_MSG_REQUEST:
1162         case DHCPV6_MSG_REBIND:
1163         case DHCPV6_MSG_RENEW:
1164                 // Update refresh timers if no fatal status code was received
1165                 if ((ret > 0) && (ret = dhcpv6_calc_refresh_timers())) {
1166                         if (orig == DHCPV6_MSG_REQUEST) {
1167                                 // All server candidates can be cleared if not yet bound
1168                                 if (!odhcp6c_is_bound())
1169                                         dhcpv6_clear_all_server_cand();
1170
1171                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1172                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1173                         } else if (orig == DHCPV6_MSG_RENEW) {
1174                                 // Send further renews if T1 is not set and
1175                                 // no updated IAs
1176                                 if (!t1) {
1177                                         if (!updated_IAs)
1178                                                 ret = -1;
1179                                         else if ((t2 - t1) > 1)
1180                                                 // Grace period of 1 second
1181                                                 t1 = 1;
1182                                 }
1183
1184                         } else if (orig == DHCPV6_MSG_REBIND) {
1185                                 // Send further rebinds if T1 and T2 is not set and
1186                                 // no updated IAs
1187                                 if (!t1 && !t2) {
1188                                         if (!updated_IAs)
1189                                                 ret = -1;
1190                                         else if ((t3 - t2) > 1)
1191                                                 // Grace period of 1 second
1192                                                 t2 = 1;
1193                                 }
1194
1195                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
1196                                 odhcp6c_add_state(STATE_SERVER_ADDR, &from->sin6_addr, 16);
1197                         }
1198                 }
1199                 break;
1200
1201         case DHCPV6_MSG_INFO_REQ:
1202                 if (ret > 0) {
1203                         // All server candidates can be cleared if not yet bound
1204                         if (!odhcp6c_is_bound())
1205                                 dhcpv6_clear_all_server_cand();
1206
1207                         t1 = refresh;
1208                 }
1209                 break;
1210
1211         default:
1212                 break;
1213         }
1214
1215         return ret;
1216 }
1217
1218 static unsigned int dhcpv6_parse_ia(void *opt, void *end)
1219 {
1220         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1221         unsigned int updated_IAs = 0;
1222         uint32_t t1, t2;
1223         uint16_t otype, olen;
1224         uint8_t *odata;
1225
1226         t1 = ntohl(ia_hdr->t1);
1227         t2 = ntohl(ia_hdr->t2);
1228
1229         if (t1 > t2)
1230                 return 0;
1231
1232         // Update address IA
1233         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1234                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0, 0,
1235                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0};
1236
1237                 entry.iaid = ia_hdr->iaid;
1238
1239                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1240                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1241                         if (olen + 4U < sizeof(*prefix))
1242                                 continue;
1243
1244                         entry.valid = ntohl(prefix->valid);
1245                         entry.preferred = ntohl(prefix->preferred);
1246
1247                         if (entry.preferred > entry.valid)
1248                                 continue;
1249
1250                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1251                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1252                         if (entry.t1 > entry.t2)
1253                                 entry.t1 = entry.t2;
1254
1255                         entry.length = prefix->prefix;
1256                         entry.target = prefix->addr;
1257                         uint16_t stype, slen;
1258                         uint8_t *sdata;
1259
1260                         // Parse PD-exclude
1261                         bool ok = true;
1262                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1263                                         odata + olen, stype, slen, sdata) {
1264                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1265                                         continue;
1266
1267                                 uint8_t elen = sdata[0];
1268                                 if (elen > 64)
1269                                         elen = 64;
1270
1271                                 if (entry.length < 32 || elen <= entry.length) {
1272                                         ok = false;
1273                                         continue;
1274                                 }
1275
1276                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1277                                 if (slen <= bytes) {
1278                                         ok = false;
1279                                         continue;
1280                                 }
1281
1282                                 uint32_t exclude = 0;
1283                                 do {
1284                                         exclude = exclude << 8 | sdata[bytes];
1285                                 } while (--bytes);
1286
1287                                 exclude >>= 8 - ((elen - entry.length) % 8);
1288                                 exclude <<= 64 - elen;
1289
1290                                 // Abusing router & priority fields for exclusion
1291                                 entry.router = entry.target;
1292                                 entry.router.s6_addr32[1] |= htonl(exclude);
1293                                 entry.priority = elen;
1294                         }
1295
1296                         if (ok) {
1297                                 if (odhcp6c_update_entry(STATE_IA_PD, &entry, 0, 0))
1298                                         updated_IAs++;
1299                         }
1300
1301                         entry.priority = 0;
1302                         memset(&entry.router, 0, sizeof(entry.router));
1303                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1304                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1305                         if (olen + 4U < sizeof(*addr))
1306                                 continue;
1307
1308                         entry.preferred = ntohl(addr->preferred);
1309                         entry.valid = ntohl(addr->valid);
1310
1311                         if (entry.preferred > entry.valid)
1312                                 continue;
1313
1314                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1315                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1316                         if (entry.t1 > entry.t2)
1317                                 entry.t1 = entry.t2;
1318
1319                         entry.length = 128;
1320                         entry.target = addr->addr;
1321
1322                         if (odhcp6c_update_entry(STATE_IA_NA, &entry, 0, 0))
1323                                 updated_IAs++;
1324                 }
1325         }
1326         return updated_IAs;
1327 }
1328
1329 static int dhcpv6_calc_refresh_timers(void)
1330 {
1331         struct odhcp6c_entry *e;
1332         size_t ia_na_entries, ia_pd_entries, i;
1333         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1334
1335         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1336         ia_na_entries /= sizeof(*e);
1337
1338         for (i = 0; i < ia_na_entries; i++) {
1339                 if (e[i].t1 < l_t1)
1340                         l_t1 = e[i].t1;
1341
1342                 if (e[i].t2 < l_t2)
1343                         l_t2 = e[i].t2;
1344
1345                 if (e[i].valid > l_t3)
1346                         l_t3 = e[i].valid;
1347         }
1348
1349         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1350         ia_pd_entries /= sizeof(*e);
1351
1352         for (i = 0; i < ia_pd_entries; i++) {
1353                 if (e[i].t1 < l_t1)
1354                         l_t1 = e[i].t1;
1355
1356                 if (e[i].t2 < l_t2)
1357                         l_t2 = e[i].t2;
1358
1359                 if (e[i].valid > l_t3)
1360                         l_t3 = e[i].valid;
1361         }
1362
1363         if (ia_pd_entries || ia_na_entries) {
1364                 t1 = l_t1;
1365                 t2 = l_t2;
1366                 t3 = l_t3;
1367         }
1368
1369         return (int)(ia_pd_entries + ia_na_entries);
1370 }
1371
1372 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1373                 const void *status_msg, int len)
1374 {
1375         const char *src = status_msg;
1376         char buf[len + 3];
1377         char *dst = buf;
1378
1379         if (len) {
1380                 *dst++ = '(';
1381                 while (len--) {
1382                         *dst = isprint((unsigned char)*src) ? *src : '?';
1383                         src++;
1384                         dst++;
1385                 }
1386                 *dst++ = ')';
1387         }
1388
1389         *dst = 0;
1390
1391         syslog(LOG_WARNING, "Server returned %s status %i %s",
1392                 scope, code, buf);
1393 }
1394
1395 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1396                 const uint16_t code, const void *status_msg, const int len,
1397                 int *ret)
1398 {
1399         dhcpv6_log_status_code(code, "message", status_msg, len);
1400
1401         switch (code) {
1402         case DHCPV6_UnspecFail:
1403                 // Generic failure
1404                 *ret = 0;
1405                 break;
1406
1407         case DHCPV6_UseMulticast:
1408                 switch(orig) {
1409                 case DHCPV6_MSG_REQUEST:
1410                 case DHCPV6_MSG_RENEW:
1411                 case DHCPV6_MSG_RELEASE:
1412                 case DHCPV6_MSG_DECLINE:
1413                         // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
1414                         server_addr = in6addr_any;
1415                         *ret = 0;
1416                         break;
1417                 default:
1418                         break;
1419                 }
1420                 break;
1421
1422         case DHCPV6_NoAddrsAvail:
1423         case DHCPV6_NoPrefixAvail:
1424                 if (orig == DHCPV6_MSG_REQUEST)
1425                         *ret = 0; // Failure
1426                 break;
1427
1428         default:
1429                 break;
1430         }
1431 }
1432
1433 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1434                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1435                 const void *status_msg, const int len,
1436                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1437 {
1438         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1439                 "IA_NA" : "IA_PD", status_msg, len);
1440
1441         switch (code) {
1442         case DHCPV6_NoBinding:
1443                 switch (orig) {
1444                 case DHCPV6_MSG_RENEW:
1445                 case DHCPV6_MSG_REBIND:
1446                         if ((*ret > 0) && !handled_status_codes[code])
1447                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1448                         break;
1449
1450                 default:
1451                         break;
1452                 }
1453                 break;
1454
1455         default:
1456                 *ret = 0;
1457                 break;
1458         }
1459 }
1460
1461 // Note this always takes ownership of cand->ia_na and cand->ia_pd
1462 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1463 {
1464         size_t cand_len, i;
1465         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1466
1467         // Remove identical duid server candidate
1468         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1469                 if (cand->duid_len == c[i].duid_len &&
1470                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1471                         free(c[i].ia_na);
1472                         free(c[i].ia_pd);
1473                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1474                         break;
1475                 }
1476         }
1477
1478         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1479                 i < cand_len / sizeof(*c); ++i) {
1480                 if (c[i].preference < cand->preference)
1481                         break;
1482         }
1483
1484         if (odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand))) {
1485                 free(cand->ia_na);
1486                 free(cand->ia_pd);
1487         }
1488 }
1489
1490 static void dhcpv6_clear_all_server_cand(void)
1491 {
1492         size_t cand_len, i;
1493         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1494
1495         // Server candidates need deep delete for IA_NA/IA_PD
1496         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1497                 free(c[i].ia_na);
1498                 free(c[i].ia_pd);
1499         }
1500         odhcp6c_clear_state(STATE_SERVER_CAND);
1501 }
1502
1503 int dhcpv6_promote_server_cand(void)
1504 {
1505         size_t cand_len;
1506         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1507         uint16_t hdr[2];
1508         int ret = DHCPV6_STATELESS;
1509
1510         // Clear lingering candidate state info
1511         odhcp6c_clear_state(STATE_SERVER_ID);
1512         odhcp6c_clear_state(STATE_IA_NA);
1513         odhcp6c_clear_state(STATE_IA_PD);
1514
1515         if (!cand_len)
1516                 return -1;
1517
1518         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1519                 na_mode = IA_MODE_NONE;
1520
1521                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1522                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1523
1524                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1525         }
1526
1527         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1528         hdr[1] = htons(cand->duid_len);
1529         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1530         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1531         accept_reconfig = cand->wants_reconfigure;
1532
1533         if (cand->ia_na_len) {
1534                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1535                 free(cand->ia_na);
1536                 if (na_mode != IA_MODE_NONE)
1537                         ret = DHCPV6_STATEFUL;
1538         }
1539
1540         if (cand->ia_pd_len) {
1541                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1542                 free(cand->ia_pd);
1543                 if (pd_mode != IA_MODE_NONE)
1544                         ret = DHCPV6_STATEFUL;
1545         }
1546
1547         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1548         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1549
1550         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1551
1552         return ret;
1553 }