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                 };
 183                 odhcp6c_add_state(STATE_ORO, oro, sizeof(oro));
 184         }
 185
 186         // Configure IPv6-options
 187         int val = 1;
 188         setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
 189         setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 190         setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
 191         val = 0;
 192         setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &val, sizeof(val));
 193         setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
 194
 195         struct sockaddr_in6 client_addr = { .sin6_family = AF_INET6,
 196                 .sin6_port = htons(DHCPV6_CLIENT_PORT), .sin6_flowinfo = 0 };
 197         if (bind(sock, (struct sockaddr*)&client_addr, sizeof(client_addr)) < 0)
 198                 return -1;
 199
 200         return 0;
 201 }
 202
 203 enum {
 204         IOV_HDR=0,
 205         IOV_ORO,
 206         IOV_ORO_REFRESH,
 207         IOV_CL_ID,
 208         IOV_SRV_ID,
 209         IOV_VENDOR_CLASS_HDR,
 210         IOV_VENDOR_CLASS,
 211         IOV_USER_CLASS_HDR,
 212         IOV_USER_CLASS,
 213         IOV_RECONF_ACCEPT,
 214         IOV_FQDN,
 215         IOV_HDR_IA_NA,
 216         IOV_IA_NA,
 217         IOV_IA_PD,
 218         IOV_TOTAL
 219 };
 220
 221 void dhcpv6_set_ia_mode(enum odhcp6c_ia_mode na, enum odhcp6c_ia_mode pd)
 222 {
 223         na_mode = na;
 224         pd_mode = pd;
 225 }
 226
 227 static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
 228 {
 229         // Build FQDN
 230         char fqdn_buf[256];
 231         gethostname(fqdn_buf, sizeof(fqdn_buf));
 232         struct {
 233                 uint16_t type;
 234                 uint16_t len;
 235                 uint8_t flags;
 236                 uint8_t data[256];
 237         } fqdn;
 238         size_t fqdn_len = 5 + dn_comp(fqdn_buf, fqdn.data,
 239                         sizeof(fqdn.data), NULL, NULL);
 240         fqdn.type = htons(DHCPV6_OPT_FQDN);
 241         fqdn.len = htons(fqdn_len - 4);
 242         fqdn.flags = 0;
 243
 244
 245         // Build Client ID
 246         size_t cl_id_len;
 247         void *cl_id = odhcp6c_get_state(STATE_CLIENT_ID, &cl_id_len);
 248
 249         // Get Server ID
 250         size_t srv_id_len;
 251         void *srv_id = odhcp6c_get_state(STATE_SERVER_ID, &srv_id_len);
 252
 253         // Build IA_PDs
 254         size_t ia_pd_entries = 0, ia_pd_len = 0;
 255         uint8_t *ia_pd;
 256
 257         if (type == DHCPV6_MSG_SOLICIT) {
 258                 odhcp6c_clear_state(STATE_IA_PD);
 259                 size_t n_prefixes;
 260                 struct odhcp6c_request_prefix *request_prefixes = odhcp6c_get_state(STATE_IA_PD_INIT, &n_prefixes);
 261                 n_prefixes /= sizeof(struct odhcp6c_request_prefix);
 262
 263                 ia_pd = alloca(n_prefixes * (sizeof(struct dhcpv6_ia_hdr) + sizeof(struct dhcpv6_ia_prefix)));
 264
 265                 for (size_t i = 0; i < n_prefixes; i++) {
 266                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 267                                 htons(DHCPV6_OPT_IA_PD),
 268                                 htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
 269                                 request_prefixes[i].iaid, 0, 0
 270                         };
 271                         struct dhcpv6_ia_prefix pref = {
 272                                 .type = htons(DHCPV6_OPT_IA_PREFIX),
 273                                 .len = htons(25), .prefix = request_prefixes[i].length
 274                         };
 275                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 276                         ia_pd_len += sizeof(hdr_ia_pd);
 277                         memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
 278                         ia_pd_len += sizeof(pref);
 279                 }
 280         } else {
 281                 struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
 282                 ia_pd_entries /= sizeof(*e);
 283
 284                 // we're too lazy to count our distinct IAIDs,
 285                 // so just allocate maximally needed space
 286                 ia_pd = alloca(ia_pd_entries * (sizeof(struct dhcpv6_ia_prefix) + 10 +
 287                                         sizeof(struct dhcpv6_ia_hdr)));
 288
 289                 for (size_t i = 0; i < ia_pd_entries; ++i) {
 290                         uint32_t iaid = e[i].iaid;
 291
 292                         // check if this is an unprocessed IAID and skip if not.
 293                         int new_iaid = 1;
 294                         for (int j = i-1; j >= 0; j--) {
 295                                 if (e[j].iaid == iaid) {
 296                                         new_iaid = 0;
 297                                         break;
 298                                 }
 299                         }
 300
 301                         if (!new_iaid)
 302                                 continue;
 303
 304                         // construct header
 305                         struct dhcpv6_ia_hdr hdr_ia_pd = {
 306                                 htons(DHCPV6_OPT_IA_PD),
 307                                 htons(sizeof(hdr_ia_pd) - 4),
 308                                 iaid, 0, 0
 309                         };
 310
 311                         memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
 312                         struct dhcpv6_ia_hdr *hdr = (struct dhcpv6_ia_hdr *) (ia_pd + ia_pd_len);
 313                         ia_pd_len += sizeof(hdr_ia_pd);
 314
 315                         for (size_t j = i; j < ia_pd_entries; j++) {
 316                                 if (e[j].iaid != iaid)
 317                                         continue;
 318
 319                                 uint8_t ex_len = 0;
 320                                 if (e[j].priority > 0)
 321                                         ex_len = ((e[j].priority - e[j].length - 1) / 8) + 6;
 322
 323                                 struct dhcpv6_ia_prefix p = {
 324                                         .type = htons(DHCPV6_OPT_IA_PREFIX),
 325                                         .len = htons(sizeof(p) - 4U + ex_len),
 326                                         .prefix = e[j].length,
 327                                         .addr = e[j].target
 328                                 };
 329
 330                                 memcpy(ia_pd + ia_pd_len, &p, sizeof(p));
 331                                 ia_pd_len += sizeof(p);
 332
 333                                 if (ex_len) {
 334                                         ia_pd[ia_pd_len++] = 0;
 335                                         ia_pd[ia_pd_len++] = DHCPV6_OPT_PD_EXCLUDE;
 336                                         ia_pd[ia_pd_len++] = 0;
 337                                         ia_pd[ia_pd_len++] = ex_len - 4;
 338                                         ia_pd[ia_pd_len++] = e[j].priority;
 339
 340                                         uint32_t excl = ntohl(e[j].router.s6_addr32[1]);
 341                                         excl >>= (64 - e[j].priority);
 342                                         excl <<= 8 - ((e[j].priority - e[j].length) % 8);
 343
 344                                         for (size_t i = ex_len - 5; i > 0; --i, excl >>= 8)
 345                                                 ia_pd[ia_pd_len + i] = excl & 0xff;
 346                                         ia_pd_len += ex_len - 5;
 347                                 }
 348
 349                                 hdr->len = htons(ntohs(hdr->len) + ntohs(p.len) + 4U);
 350                         }
 351                 }
 352         }
 353
 354         if (ia_pd_entries > 0)
 355                 request_prefix = 1;
 356
 357         // Build IA_NAs
 358         size_t ia_na_entries, ia_na_len = 0;
 359         void *ia_na = NULL;
 360         struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
 361         ia_na_entries /= sizeof(*e);
 362
 363         struct dhcpv6_ia_hdr hdr_ia_na = {
 364                 htons(DHCPV6_OPT_IA_NA),
 365                 htons(sizeof(hdr_ia_na) - 4),
 366                 1, 0, 0
 367         };
 368
 369         struct dhcpv6_ia_addr pa[ia_na_entries];
 370         for (size_t i = 0; i < ia_na_entries; ++i) {
 371                 pa[i].type = htons(DHCPV6_OPT_IA_ADDR);
 372                 pa[i].len = htons(sizeof(pa[i]) - 4U);
 373                 pa[i].addr = e[i].target;
 374                 pa[i].preferred = 0;
 375                 pa[i].valid = 0;
 376         }
 377
 378         ia_na = pa;
 379         ia_na_len = sizeof(pa);
 380         hdr_ia_na.len = htons(ntohs(hdr_ia_na.len) + ia_na_len);
 381
 382         // Reconfigure Accept
 383         struct {
 384                 uint16_t type;
 385                 uint16_t length;
 386         } reconf_accept = {htons(DHCPV6_OPT_RECONF_ACCEPT), 0};
 387
 388         // Request Information Refresh
 389         uint16_t oro_refresh = htons(DHCPV6_OPT_INFO_REFRESH);
 390
 391         // Build vendor-class option
 392         size_t vendor_class_len, user_class_len;
 393         struct dhcpv6_vendorclass *vendor_class = odhcp6c_get_state(STATE_VENDORCLASS, &vendor_class_len);
 394         void *user_class = odhcp6c_get_state(STATE_USERCLASS, &user_class_len);
 395
 396         struct {
 397                 uint16_t type;
 398                 uint16_t length;
 399         } vendor_class_hdr = {htons(DHCPV6_OPT_VENDOR_CLASS), htons(vendor_class_len)};
 400
 401         struct {
 402                 uint16_t type;
 403                 uint16_t length;
 404         } user_class_hdr = {htons(DHCPV6_OPT_USER_CLASS), htons(user_class_len)};
 405
 406         // Prepare Header
 407         size_t oro_len;
 408         void *oro = odhcp6c_get_state(STATE_ORO, &oro_len);
 409         struct {
 410                 uint8_t type;
 411                 uint8_t trid[3];
 412                 uint16_t elapsed_type;
 413                 uint16_t elapsed_len;
 414                 uint16_t elapsed_value;
 415                 uint16_t oro_type;
 416                 uint16_t oro_len;
 417         } hdr = {
 418                 type, {trid[0], trid[1], trid[2]},
 419                 htons(DHCPV6_OPT_ELAPSED), htons(2),
 420                         htons((ecs > 0xffff) ? 0xffff : ecs),
 421                 htons(DHCPV6_OPT_ORO), htons(oro_len),
 422         };
 423
 424         struct iovec iov[IOV_TOTAL] = {
 425                 [IOV_HDR] = {&hdr, sizeof(hdr)},
 426                 [IOV_ORO] = {oro, oro_len},
 427                 [IOV_ORO_REFRESH] = {&oro_refresh, 0},
 428                 [IOV_CL_ID] = {cl_id, cl_id_len},
 429                 [IOV_SRV_ID] = {srv_id, srv_id_len},
 430                 [IOV_VENDOR_CLASS_HDR] = {&vendor_class_hdr, vendor_class_len ? sizeof(vendor_class_hdr) : 0},
 431                 [IOV_VENDOR_CLASS] = {vendor_class, vendor_class_len},
 432                 [IOV_USER_CLASS_HDR] = {&user_class_hdr, user_class_len ? sizeof(user_class_hdr) : 0},
 433                 [IOV_USER_CLASS] = {user_class, user_class_len},
 434                 [IOV_RECONF_ACCEPT] = {&reconf_accept, sizeof(reconf_accept)},
 435                 [IOV_FQDN] = {&fqdn, fqdn_len},
 436                 [IOV_HDR_IA_NA] = {&hdr_ia_na, sizeof(hdr_ia_na)},
 437                 [IOV_IA_NA] = {ia_na, ia_na_len},
 438                 [IOV_IA_PD] = {ia_pd, ia_pd_len},
 439         };
 440
 441         size_t cnt = IOV_TOTAL;
 442         if (type == DHCPV6_MSG_INFO_REQ) {
 443                 cnt = 9;
 444                 iov[IOV_ORO_REFRESH].iov_len = sizeof(oro_refresh);
 445                 hdr.oro_len = htons(oro_len + sizeof(oro_refresh));
 446         } else if (!request_prefix) {
 447                 cnt = 13;
 448         }
 449
 450         // Disable IAs if not used
 451         if (type != DHCPV6_MSG_SOLICIT && ia_na_len == 0)
 452                 iov[IOV_HDR_IA_NA].iov_len = 0;
 453
 454         if (na_mode == IA_MODE_NONE)
 455                 iov[IOV_HDR_IA_NA].iov_len = 0;
 456
 457         if ((type != DHCPV6_MSG_SOLICIT && type != DHCPV6_MSG_REQUEST) ||
 458                         !(client_options & DHCPV6_ACCEPT_RECONFIGURE))
 459                 iov[IOV_RECONF_ACCEPT].iov_len = 0;
 460
 461         if (!(client_options & DHCPV6_CLIENT_FQDN))
 462                 iov[IOV_FQDN].iov_len = 0;
 463
 464         struct sockaddr_in6 srv = {AF_INET6, htons(DHCPV6_SERVER_PORT),
 465                 0, ALL_DHCPV6_RELAYS, ifindex};
 466         struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 467
 468         sendmsg(sock, &msg, 0);
 469 }
 470
 471
 472 static int64_t dhcpv6_rand_delay(int64_t time)
 473 {
 474         int random;
 475         odhcp6c_random(&random, sizeof(random));
 476         return (time * ((int64_t)random % 1000LL)) / 10000LL;
 477 }
 478
 479
 480 int dhcpv6_request(enum dhcpv6_msg type)
 481 {
 482         uint8_t rc = 0;
 483         uint64_t timeout = UINT32_MAX;
 484         struct dhcpv6_retx *retx = &dhcpv6_retx[type];
 485
 486         if (retx->delay) {
 487                 struct timespec ts = {0, 0};
 488                 ts.tv_nsec = dhcpv6_rand_delay(10 * DHCPV6_REQ_DELAY);
 489                 nanosleep(&ts, NULL);
 490         }
 491
 492         if (type == DHCPV6_MSG_UNKNOWN)
 493                 timeout = t1;
 494         else if (type == DHCPV6_MSG_RENEW)
 495                 timeout = (t2 > t1) ? t2 - t1 : ((t1 == UINT32_MAX) ? UINT32_MAX : 0);
 496         else if (type == DHCPV6_MSG_REBIND)
 497                 timeout = (t3 > t2) ? t3 - t2 : ((t2 == UINT32_MAX) ? UINT32_MAX : 0);
 498
 499         if (timeout == 0)
 500                 return -1;
 501
 502         syslog(LOG_NOTICE, "Starting %s transaction (timeout %llus, max rc %d)",
 503                         retx->name, (unsigned long long)timeout, retx->max_rc);
 504
 505         uint64_t start = odhcp6c_get_milli_time(), round_start = start, elapsed;
 506
 507         // Generate transaction ID
 508         uint8_t trid[3] = {0, 0, 0};
 509         if (type != DHCPV6_MSG_UNKNOWN)
 510                 odhcp6c_random(trid, sizeof(trid));
 511         ssize_t len = -1;
 512         int64_t rto = 0;
 513
 514         do {
 515                 if (rto == 0) {
 516                         int64_t delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 517
 518                         // First RT MUST be strictly greater than IRT for solicit messages (RFC3313 17.1.2)
 519                         while (type == DHCPV6_MSG_SOLICIT && delay <= 0)
 520                                 delay = dhcpv6_rand_delay(retx->init_timeo * 1000);
 521
 522                         rto = (retx->init_timeo * 1000 + delay);
 523                 }
 524                 else
 525                         rto = (2 * rto + dhcpv6_rand_delay(rto));
 526
 527                 if (retx->max_timeo && (rto >= retx->max_timeo * 1000))
 528                         rto = retx->max_timeo * 1000 +
 529                                 dhcpv6_rand_delay(retx->max_timeo * 1000);
 530
 531                 // Calculate end for this round and elapsed time
 532                 uint64_t round_end = round_start + rto;
 533                 elapsed = round_start - start;
 534
 535                 // Don't wait too long if timeout differs from infinite
 536                 if ((timeout != UINT32_MAX) && (round_end - start > timeout * 1000))
 537                         round_end = timeout * 1000 + start;
 538
 539                 // Built and send package
 540                 if (type != DHCPV6_MSG_UNKNOWN) {
 541                         if (type != DHCPV6_MSG_SOLICIT)
 542                                 syslog(LOG_NOTICE, "Send %s message (elapsed %llums, rc %d)",
 543                                                 retx->name, (unsigned long long)elapsed, rc);
 544                         dhcpv6_send(type, trid, elapsed / 10);
 545                         rc++;
 546                 }
 547
 548                 // Receive rounds
 549                 for (; len < 0 && (round_start < round_end);
 550                                 round_start = odhcp6c_get_milli_time()) {
 551                         uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
 552                         struct iovec iov = {buf, sizeof(buf)};
 553                         struct msghdr msg = {NULL, 0, &iov, 1,
 554                                         cmsg_buf, sizeof(cmsg_buf), 0};
 555                         struct in6_pktinfo *pktinfo = NULL;
 556
 557                         // Check for pending signal
 558                         if (odhcp6c_signal_process())
 559                                 return -1;
 560
 561                         // Set timeout for receiving
 562                         uint64_t t = round_end - round_start;
 563                         struct timeval tv = {t / 1000, (t % 1000) * 1000};
 564                         setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO,
 565                                         &tv, sizeof(tv));
 566
 567                         // Receive cycle
 568                         len = recvmsg(sock, &msg, 0);
 569                         if (len < 0)
 570                                 continue;
 571
 572                         for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL;
 573                                 ch = CMSG_NXTHDR(&msg, ch)) {
 574                                 if (ch->cmsg_level == SOL_IPV6 &&
 575                                         ch->cmsg_type == IPV6_PKTINFO) {
 576                                         pktinfo = (struct in6_pktinfo *)CMSG_DATA(ch);
 577                                         break;
 578                                 }
 579                         }
 580
 581                         if (pktinfo == NULL) {
 582                                 len = -1;
 583                                 continue;
 584                         }
 585
 586                         if (!dhcpv6_response_is_valid(buf, len, trid,
 587                                                         type, &pktinfo->ipi6_addr)) {
 588                                 len = -1;
 589                                 continue;
 590                         }
 591
 592                         uint8_t *opt = &buf[4];
 593                         uint8_t *opt_end = opt + len - 4;
 594
 595                         round_start = odhcp6c_get_milli_time();
 596                         elapsed = round_start - start;
 597                         syslog(LOG_NOTICE, "Got a valid reply after "
 598                                         "%llums", (unsigned long long)elapsed);
 599
 600                         if (retx->handler_reply)
 601                                 len = retx->handler_reply(type, rc, opt, opt_end);
 602
 603                         if (len > 0 && round_end - round_start > 1000)
 604                                 round_end = 1000 + round_start;
 605                 }
 606
 607                 // Allow
 608                 if (retx->handler_finish)
 609                         len = retx->handler_finish();
 610         } while (len < 0 && ((timeout == UINT32_MAX) || (elapsed / 1000 < timeout)) &&
 611                         (!retx->max_rc || rc < retx->max_rc));
 612         return len;
 613 }
 614
 615 // Message validation checks according to RFC3315 chapter 15
 616 static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 617                 const uint8_t transaction[3], enum dhcpv6_msg type,
 618                 const struct in6_addr *daddr)
 619 {
 620         const struct dhcpv6_header *rep = buf;
 621         if (len < (ssize_t)sizeof(*rep) || memcmp(rep->tr_id,
 622                         transaction, sizeof(rep->tr_id)))
 623                 return false; // Invalid reply
 624
 625         if (type == DHCPV6_MSG_SOLICIT) {
 626                 if (rep->msg_type != DHCPV6_MSG_ADVERT &&
 627                                 rep->msg_type != DHCPV6_MSG_REPLY)
 628                         return false;
 629         } else if (type == DHCPV6_MSG_UNKNOWN) {
 630                 if (!accept_reconfig || rep->msg_type != DHCPV6_MSG_RECONF)
 631                         return false;
 632         } else if (rep->msg_type != DHCPV6_MSG_REPLY) {
 633                 return false;
 634         }
 635
 636         uint8_t *end = ((uint8_t*)buf) + len, *odata = NULL,
 637                 rcmsg = DHCPV6_MSG_UNKNOWN;
 638         uint16_t otype, olen = UINT16_MAX;
 639         bool clientid_ok = false, serverid_ok = false, rcauth_ok = false,
 640                 ia_present = false, options_valid = true;
 641
 642         size_t client_id_len, server_id_len;
 643         void *client_id = odhcp6c_get_state(STATE_CLIENT_ID, &client_id_len);
 644         void *server_id = odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 645
 646         dhcpv6_for_each_option(&rep[1], end, otype, olen, odata) {
 647                 if (otype == DHCPV6_OPT_CLIENTID) {
 648                         clientid_ok = (olen + 4U == client_id_len) && !memcmp(
 649                                         &odata[-4], client_id, client_id_len);
 650                 } else if (otype == DHCPV6_OPT_SERVERID) {
 651                         if (server_id_len)
 652                                 serverid_ok = (olen + 4U == server_id_len) && !memcmp(
 653                                                 &odata[-4], server_id, server_id_len);
 654                         else
 655                                 serverid_ok = true;
 656                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 657                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 658                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 659                         if (r->protocol != 3 || r->algorithm != 1 || r->reconf_type != 2)
 660                                 continue;
 661
 662                         md5_ctx_t md5;
 663                         uint8_t serverhash[16], secretbytes[64], hash[16];
 664                         memcpy(serverhash, r->key, sizeof(serverhash));
 665                         memset(r->key, 0, sizeof(r->key));
 666
 667                         memset(secretbytes, 0, sizeof(secretbytes));
 668                         memcpy(secretbytes, reconf_key, sizeof(reconf_key));
 669
 670                         for (size_t i = 0; i < sizeof(secretbytes); ++i)
 671                                 secretbytes[i] ^= 0x36;
 672
 673                         md5_begin(&md5);
 674                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 675                         md5_hash(buf, len, &md5);
 676                         md5_end(hash, &md5);
 677
 678                         for (size_t i = 0; i < sizeof(secretbytes); ++i) {
 679                                 secretbytes[i] ^= 0x36;
 680                                 secretbytes[i] ^= 0x5c;
 681                         }
 682
 683                         md5_begin(&md5);
 684                         md5_hash(secretbytes, sizeof(secretbytes), &md5);
 685                         md5_hash(hash, 16, &md5);
 686                         md5_end(hash, &md5);
 687
 688                         rcauth_ok = !memcmp(hash, serverhash, sizeof(hash));
 689                 } else if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1) {
 690                         rcmsg = odata[0];
 691                 } else if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)) {
 692                         ia_present = true;
 693                         if (olen < sizeof(struct dhcpv6_ia_hdr))
 694                                 options_valid = false;
 695                 }
 696                 else if ((otype == DHCPV6_OPT_IA_ADDR) || (otype == DHCPV6_OPT_IA_PREFIX) ||
 697                                 (otype == DHCPV6_OPT_PD_EXCLUDE)) {
 698                         // Options are not allowed on global level
 699                         options_valid = false;
 700                 }
 701         }
 702
 703         if (!options_valid || ((odata + olen) > end))
 704                 return false;
 705
 706         if (type == DHCPV6_MSG_INFO_REQ && ia_present)
 707                 return false;
 708
 709         if (rep->msg_type == DHCPV6_MSG_RECONF) {
 710                 if ((rcmsg != DHCPV6_MSG_RENEW && rcmsg != DHCPV6_MSG_INFO_REQ) ||
 711                         (rcmsg == DHCPV6_MSG_INFO_REQ && ia_present) ||
 712                         !rcauth_ok || IN6_IS_ADDR_MULTICAST(daddr))
 713                         return false;
 714         }
 715
 716         return clientid_ok && serverid_ok;
 717 }
 718
 719
 720 int dhcpv6_poll_reconfigure(void)
 721 {
 722         int ret = dhcpv6_request(DHCPV6_MSG_UNKNOWN);
 723         if (ret != -1)
 724                 ret = dhcpv6_request(ret);
 725
 726         return ret;
 727 }
 728
 729
 730 static int dhcpv6_handle_reconfigure(_unused enum dhcpv6_msg orig, const int rc,
 731                 const void *opt, const void *end)
 732 {
 733         uint16_t otype, olen;
 734         uint8_t *odata, msg = DHCPV6_MSG_RENEW;
 735         dhcpv6_for_each_option(opt, end, otype, olen, odata)
 736                 if (otype == DHCPV6_OPT_RECONF_MESSAGE && olen == 1 && (
 737                                 odata[0] == DHCPV6_MSG_RENEW ||
 738                                 odata[0] == DHCPV6_MSG_INFO_REQ))
 739                         msg = odata[0];
 740
 741         dhcpv6_handle_reply(DHCPV6_MSG_UNKNOWN, rc, NULL, NULL);
 742         return msg;
 743 }
 744
 745
 746 // Collect all advertised servers
 747 static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 748                 const void *opt, const void *end)
 749 {
 750         uint16_t olen, otype;
 751         uint8_t *odata, pref = 0;
 752         struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
 753                                         DHCPV6_SOL_MAX_RT,
 754                                         DHCPV6_INF_MAX_RT, NULL, NULL, 0, 0};
 755         bool have_na = false;
 756         int have_pd = 0;
 757
 758         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 759                 if (orig == DHCPV6_MSG_SOLICIT &&
 760                                 (otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA) &&
 761                                 olen > sizeof(struct dhcpv6_ia_hdr)) {
 762                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 763                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 764                 }
 765
 766                 if (otype == DHCPV6_OPT_SERVERID && olen <= 130) {
 767                         memcpy(cand.duid, odata, olen);
 768                         cand.duid_len = olen;
 769                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 770                         int error = ((int)odata[0] << 8 | (int)odata[1]);
 771
 772                         switch (error) {
 773                         case DHCPV6_NoPrefixAvail:
 774                                 // Status code on global level
 775                                 cand.preference -= 2000;
 776                                 break;
 777
 778                         default :
 779                                 break;
 780                         }
 781                 } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
 782                                 cand.preference >= 0) {
 783                         cand.preference = pref = odata[0];
 784                 } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 785                         cand.wants_reconfigure = true;
 786                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
 787                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
 788                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 789                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 790                                 cand.sol_max_rt = sol_max_rt;
 791                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
 792                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
 793                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 794                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 795                                 cand.inf_max_rt = inf_max_rt;
 796                 } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
 797                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 798                         uint8_t *oend = odata + olen, *d;
 799                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d) {
 800                                 if (otype == DHCPV6_OPT_IA_PREFIX && (olen + 4) >=
 801                                                 (uint16_t)sizeof(struct dhcpv6_ia_prefix)) {
 802                                         struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&d[-4];
 803                                         have_pd = p->prefix;
 804                                 }
 805                         }
 806                 } else if (otype == DHCPV6_OPT_IA_NA) {
 807                         struct dhcpv6_ia_hdr *h = (struct dhcpv6_ia_hdr*)&odata[-4];
 808                         uint8_t *oend = odata + olen, *d;
 809                         dhcpv6_for_each_option(&h[1], oend, otype, olen, d)
 810                                 if (otype == DHCPV6_OPT_IA_ADDR)
 811                                         have_na = true;
 812                 }
 813         }
 814
 815         if ((!have_na && na_mode == IA_MODE_FORCE) ||
 816                         (!have_pd && pd_mode == IA_MODE_FORCE)) {
 817                 /*
 818                  * RFC7083 states to process the SOL_MAX_RT and
 819                  * INF_MAX_RT options even if the DHCPv6 server
 820                  * did not propose any IA_NA and/or IA_PD
 821                  */
 822                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand.sol_max_rt;
 823                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand.inf_max_rt;
 824                 return -1;
 825         }
 826
 827         if (na_mode != IA_MODE_NONE && !have_na) {
 828                 cand.has_noaddravail = true;
 829                 cand.preference -= 1000;
 830         }
 831
 832         if (pd_mode != IA_MODE_NONE) {
 833                 if (have_pd)
 834                         cand.preference += 2000 + (128 - have_pd);
 835                 else
 836                         cand.preference -= 2000;
 837         }
 838
 839         if (cand.duid_len > 0) {
 840                 cand.ia_na = odhcp6c_move_state(STATE_IA_NA, &cand.ia_na_len);
 841                 cand.ia_pd = odhcp6c_move_state(STATE_IA_PD, &cand.ia_pd_len);
 842                 dhcpv6_add_server_cand(&cand);
 843         }
 844
 845         return (rc > 1 || (pref == 255 && cand.preference > 0)) ? 1 : -1;
 846 }
 847
 848
 849 static int dhcpv6_commit_advert(void)
 850 {
 851         return dhcpv6_promote_server_cand();
 852 }
 853
 854
 855 static int dhcpv6_handle_rebind_reply(enum dhcpv6_msg orig, const int rc,
 856                 const void *opt, const void *end)
 857 {
 858         dhcpv6_handle_advert(orig, rc, opt, end);
 859         if (dhcpv6_commit_advert() < 0)
 860                 return -1;
 861
 862         return dhcpv6_handle_reply(orig, rc, opt, end);
 863 }
 864
 865
 866 static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 867                 const void *opt, const void *end)
 868 {
 869         uint8_t *odata;
 870         uint16_t otype, olen;
 871         uint32_t refresh = UINT32_MAX;
 872         int ret = 1;
 873         bool handled_status_codes[_DHCPV6_Status_Max] = { false, };
 874
 875         odhcp6c_expire();
 876
 877         if (orig == DHCPV6_MSG_UNKNOWN) {
 878                 static time_t last_update = 0;
 879                 time_t now = odhcp6c_get_milli_time() / 1000;
 880
 881                 uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 882                 last_update = now;
 883
 884                 if (t1 != UINT32_MAX)
 885                         t1 -= elapsed;
 886
 887                 if (t2 != UINT32_MAX)
 888                         t2 -= elapsed;
 889
 890                 if (t3 != UINT32_MAX)
 891                         t3 -= elapsed;
 892
 893                 if (t1 < 0)
 894                         t1 = 0;
 895
 896                 if (t2 < 0)
 897                         t2 = 0;
 898
 899                 if (t3 < 0)
 900                         t3 = 0;
 901         }
 902
 903         if (orig == DHCPV6_MSG_REQUEST && !odhcp6c_is_bound()) {
 904                 // Delete NA and PD we have in the state from the Advert
 905                 odhcp6c_clear_state(STATE_IA_NA);
 906                 odhcp6c_clear_state(STATE_IA_PD);
 907         }
 908
 909         if (opt) {
 910                 odhcp6c_clear_state(STATE_DNS);
 911                 odhcp6c_clear_state(STATE_SEARCH);
 912                 odhcp6c_clear_state(STATE_SNTP_IP);
 913                 odhcp6c_clear_state(STATE_NTP_IP);
 914                 odhcp6c_clear_state(STATE_NTP_FQDN);
 915                 odhcp6c_clear_state(STATE_SIP_IP);
 916                 odhcp6c_clear_state(STATE_SIP_FQDN);
 917                 odhcp6c_clear_state(STATE_AFTR_NAME);
 918         }
 919
 920         // Parse and find all matching IAs
 921         dhcpv6_for_each_option(opt, end, otype, olen, odata) {
 922                 if ((otype == DHCPV6_OPT_IA_PD || otype == DHCPV6_OPT_IA_NA)
 923                                 && olen > sizeof(struct dhcpv6_ia_hdr)) {
 924                         struct dhcpv6_ia_hdr *ia_hdr = (void*)(&odata[-4]);
 925
 926                         // Test ID
 927                         if (ia_hdr->iaid != 1 && otype == DHCPV6_OPT_IA_NA)
 928                                 continue;
 929
 930                         uint16_t code = DHCPV6_Success;
 931                         uint16_t stype, slen;
 932                         uint8_t *sdata;
 933                         // Get and handle status code
 934                         dhcpv6_for_each_option(&ia_hdr[1], odata + olen,
 935                                         stype, slen, sdata) {
 936                                 if (stype == DHCPV6_OPT_STATUS && slen >= 2) {
 937                                         uint8_t *mdata = (slen > 2) ? &sdata[2] : NULL;
 938                                         uint16_t mlen = (slen > 2) ? slen - 2 : 0;
 939
 940                                         code = ((int)sdata[0]) << 8 | ((int)sdata[1]);
 941
 942                                         if (code == DHCPV6_Success)
 943                                                 continue;
 944
 945                                         dhcpv6_handle_ia_status_code(orig, ia_hdr,
 946                                                 code, mdata, mlen, handled_status_codes, &ret);
 947
 948
 949                                         if (ret > 0)
 950                                                 return ret;
 951                                         break;
 952                                 }
 953                         }
 954
 955                         if (code != DHCPV6_Success)
 956                                 continue;
 957
 958                         dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
 959                 } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
 960                         uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
 961                         uint16_t mlen = (olen > 2) ? olen - 2 : 0;
 962                         uint16_t code = ((int)odata[0]) << 8 | ((int)odata[1]);
 963
 964                         dhcpv6_handle_status_code(orig, code, mdata, mlen, &ret);
 965                 }
 966                 else if (otype == DHCPV6_OPT_DNS_SERVERS) {
 967                         if (olen % 16 == 0)
 968                                 odhcp6c_add_state(STATE_DNS, odata, olen);
 969                 } else if (otype == DHCPV6_OPT_DNS_DOMAIN) {
 970                         odhcp6c_add_state(STATE_SEARCH, odata, olen);
 971                 } else if (otype == DHCPV6_OPT_SNTP_SERVERS) {
 972                         if (olen % 16 == 0)
 973                                 odhcp6c_add_state(STATE_SNTP_IP, odata, olen);
 974                 } else if (otype == DHCPV6_OPT_NTP_SERVER) {
 975                         uint16_t stype, slen;
 976                         uint8_t *sdata;
 977                         // Test status and bail if error
 978                         dhcpv6_for_each_option(odata, odata + olen,
 979                                         stype, slen, sdata) {
 980                                 if (slen == 16 && (stype == NTP_MC_ADDR ||
 981                                                 stype == NTP_SRV_ADDR))
 982                                         odhcp6c_add_state(STATE_NTP_IP,
 983                                                         sdata, slen);
 984                                 else if (slen > 0 && stype == NTP_SRV_FQDN)
 985                                         odhcp6c_add_state(STATE_NTP_FQDN,
 986                                                         sdata, slen);
 987                         }
 988                 } else if (otype == DHCPV6_OPT_SIP_SERVER_A) {
 989                         if (olen == 16)
 990                                 odhcp6c_add_state(STATE_SIP_IP, odata, olen);
 991                 } else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 992                         odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 993                 } else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
 994                         refresh = ntohl(*((uint32_t*)odata));
 995                 } else if (otype == DHCPV6_OPT_AUTH && olen == -4 +
 996                                 sizeof(struct dhcpv6_auth_reconfigure)) {
 997                         struct dhcpv6_auth_reconfigure *r = (void*)&odata[-4];
 998                         if (r->protocol == 3 && r->algorithm == 1 &&
 999                                         r->reconf_type == 1)
1000                                 memcpy(reconf_key, r->key, sizeof(r->key));
1001                 } else if (otype == DHCPV6_OPT_AFTR_NAME && olen > 3) {
1002                         size_t cur_len;
1003                         odhcp6c_get_state(STATE_AFTR_NAME, &cur_len);
1004                         if (cur_len == 0)
1005                                 odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
1006                 } else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
1007                         uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
1008                         if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
1009                                         sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
1010                                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
1011                 } else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
1012                         uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
1013                         if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
1014                                         inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
1015                                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
1016 #ifdef EXT_CER_ID
1017                 } else if (otype == DHCPV6_OPT_CER_ID && olen == -4 +
1018                                 sizeof(struct dhcpv6_cer_id)) {
1019                         struct dhcpv6_cer_id *cer_id = (void*)&odata[-4];
1020                         struct in6_addr any = IN6ADDR_ANY_INIT;
1021                         if (memcmp(&cer_id->addr, &any, sizeof(any)))
1022                                 odhcp6c_add_state(STATE_CER, &cer_id->addr, sizeof(any));
1023 #endif
1024                 } else if (otype != DHCPV6_OPT_CLIENTID &&
1025                                 otype != DHCPV6_OPT_SERVERID) {
1026                         odhcp6c_add_state(STATE_CUSTOM_OPTS,
1027                                         &odata[-4], olen + 4);
1028                 }
1029         }
1030
1031         if (orig != DHCPV6_MSG_INFO_REQ) {
1032                 // Update refresh timers if no fatal status code was received
1033                 if ((ret > 0) && dhcpv6_calc_refresh_timers()) {
1034                         switch (orig) {
1035                         case DHCPV6_MSG_RENEW:
1036                                 // Send further renews if T1 is not set
1037                                 if (!t1)
1038                                         ret = -1;
1039                                 break;
1040                         case DHCPV6_MSG_REBIND:
1041                                 // Send further rebinds if T1 and T2 is not set
1042                                 if (!t1 && !t2)
1043                                         ret = -1;
1044                                 break;
1045
1046                         case DHCPV6_MSG_REQUEST:
1047                                 // All server candidates can be cleared if not yet bound
1048                                 if (!odhcp6c_is_bound())
1049                                         dhcpv6_clear_all_server_cand();
1050
1051                         default :
1052                                 break;
1053                         }
1054                 }
1055         }
1056         else if (ret > 0) {
1057                 // All server candidates can be cleared if not yet bound
1058                 if (!odhcp6c_is_bound())
1059                         dhcpv6_clear_all_server_cand();
1060
1061                 t1 = refresh;
1062         }
1063
1064         return ret;
1065 }
1066
1067
1068 static int dhcpv6_parse_ia(void *opt, void *end)
1069 {
1070         struct dhcpv6_ia_hdr *ia_hdr = (struct dhcpv6_ia_hdr *)opt;
1071         int parsed_ia = 0;
1072         uint32_t t1, t2;
1073         uint16_t otype, olen;
1074         uint8_t *odata;
1075
1076         t1 = ntohl(ia_hdr->t1);
1077         t2 = ntohl(ia_hdr->t2);
1078
1079         if (t1 > t2)
1080                 return 0;
1081
1082         // Update address IA
1083         dhcpv6_for_each_option(&ia_hdr[1], end, otype, olen, odata) {
1084                 struct odhcp6c_entry entry = {IN6ADDR_ANY_INIT, 0, 0,
1085                                 IN6ADDR_ANY_INIT, 0, 0, 0, 0, 0, 0};
1086
1087                 entry.iaid = ia_hdr->iaid;
1088
1089                 if (otype == DHCPV6_OPT_IA_PREFIX) {
1090                         struct dhcpv6_ia_prefix *prefix = (void*)&odata[-4];
1091                         if (olen + 4U < sizeof(*prefix))
1092                                 continue;
1093
1094                         entry.valid = ntohl(prefix->valid);
1095                         entry.preferred = ntohl(prefix->preferred);
1096
1097                         if (entry.preferred > entry.valid)
1098                                 continue;
1099
1100                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1101                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1102                         if (entry.t1 > entry.t2)
1103                                 entry.t1 = entry.t2;
1104
1105                         entry.length = prefix->prefix;
1106                         entry.target = prefix->addr;
1107                         uint16_t stype, slen;
1108                         uint8_t *sdata;
1109
1110 #ifdef EXT_PREFIX_CLASS
1111                         // Find prefix class, if any
1112                         dhcpv6_for_each_option(&prefix[1], odata + olen,
1113                                         stype, slen, sdata)
1114                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1115                                         entry.class = sdata[0] << 8 | sdata[1];
1116 #endif
1117
1118                         // Parse PD-exclude
1119                         bool ok = true;
1120                         dhcpv6_for_each_option(odata + sizeof(*prefix) - 4U,
1121                                         odata + olen, stype, slen, sdata) {
1122                                 if (stype != DHCPV6_OPT_PD_EXCLUDE || slen < 2)
1123                                         continue;
1124
1125                                 uint8_t elen = sdata[0];
1126                                 if (elen > 64)
1127                                         elen = 64;
1128
1129                                 if (elen <= 32 || elen <= entry.length) {
1130                                         ok = false;
1131                                         continue;
1132                                 }
1133
1134
1135                                 uint8_t bytes = ((elen - entry.length - 1) / 8) + 1;
1136                                 if (slen <= bytes) {
1137                                         ok = false;
1138                                         continue;
1139                                 }
1140
1141                                 uint32_t exclude = 0;
1142                                 do {
1143                                         exclude = exclude << 8 | sdata[bytes];
1144                                 } while (--bytes);
1145
1146                                 exclude >>= 8 - ((elen - entry.length) % 8);
1147                                 exclude <<= 64 - elen;
1148
1149                                 // Abusing router & priority fields for exclusion
1150                                 entry.router = entry.target;
1151                                 entry.router.s6_addr32[1] |= htonl(exclude);
1152                                 entry.priority = elen;
1153                         }
1154
1155                         if (ok) {
1156                                 odhcp6c_update_entry(STATE_IA_PD, &entry);
1157                                 parsed_ia++;
1158                         }
1159
1160                         entry.priority = 0;
1161                         memset(&entry.router, 0, sizeof(entry.router));
1162                 } else if (otype == DHCPV6_OPT_IA_ADDR) {
1163                         struct dhcpv6_ia_addr *addr = (void*)&odata[-4];
1164                         if (olen + 4U < sizeof(*addr))
1165                                 continue;
1166
1167                         entry.preferred = ntohl(addr->preferred);
1168                         entry.valid = ntohl(addr->valid);
1169
1170                         if (entry.preferred > entry.valid)
1171                                 continue;
1172
1173                         entry.t1 = (t1 ? t1 : (entry.preferred != UINT32_MAX ? 0.5 * entry.preferred : UINT32_MAX));
1174                         entry.t2 = (t2 ? t2 : (entry.preferred != UINT32_MAX ? 0.8 * entry.preferred : UINT32_MAX));
1175                         if (entry.t1 > entry.t2)
1176                                 entry.t1 = entry.t2;
1177
1178                         entry.length = 128;
1179                         entry.target = addr->addr;
1180
1181 #ifdef EXT_PREFIX_CLASS
1182                         uint16_t stype, slen;
1183                         uint8_t *sdata;
1184                         // Find prefix class, if any
1185                         dhcpv6_for_each_option(&addr[1], odata + olen,
1186                                         stype, slen, sdata)
1187                                 if (stype == DHCPV6_OPT_PREFIX_CLASS && slen == 2)
1188                                         entry.class = sdata[0] << 8 | sdata[1];
1189 #endif
1190
1191                         odhcp6c_update_entry(STATE_IA_NA, &entry);
1192                         parsed_ia++;
1193                 }
1194         }
1195         return parsed_ia;
1196 }
1197
1198
1199 static int dhcpv6_calc_refresh_timers(void)
1200 {
1201         struct odhcp6c_entry *e;
1202         size_t ia_na_entries, ia_pd_entries, i;
1203         int64_t l_t1 = UINT32_MAX, l_t2 = UINT32_MAX, l_t3 = 0;
1204
1205         e = odhcp6c_get_state(STATE_IA_NA, &ia_na_entries);
1206         ia_na_entries /= sizeof(*e);
1207         for (i = 0; i < ia_na_entries; i++) {
1208                 if (e[i].t1 < l_t1)
1209                         l_t1 = e[i].t1;
1210
1211                 if (e[i].t2 < l_t2)
1212                         l_t2 = e[i].t2;
1213
1214                 if (e[i].valid > l_t3)
1215                         l_t3 = e[i].valid;
1216         }
1217
1218         e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);
1219         ia_pd_entries /= sizeof(*e);
1220         for (i = 0; i < ia_pd_entries; i++) {
1221                 if (e[i].t1 < l_t1)
1222                         l_t1 = e[i].t1;
1223
1224                 if (e[i].t2 < l_t2)
1225                         l_t2 = e[i].t2;
1226
1227                 if (e[i].valid > l_t3)
1228                         l_t3 = e[i].valid;
1229         }
1230
1231         if (ia_pd_entries || ia_na_entries) {
1232                 t1 = l_t1;
1233                 t2 = l_t2;
1234                 t3 = l_t3;
1235         } else {
1236                 t1 = 600;
1237         }
1238
1239         return (int)(ia_pd_entries + ia_na_entries);
1240 }
1241
1242
1243 static void dhcpv6_log_status_code(const uint16_t code, const char *scope,
1244                 const void *status_msg, const int len)
1245 {
1246         uint8_t buf[len + 3];
1247
1248         memset(buf, 0, sizeof(buf));
1249         if (len) {
1250                 buf[0] = '(';
1251                 memcpy(&buf[1], status_msg, len);
1252                 buf[len + 1] = ')';
1253         }
1254
1255         syslog(LOG_WARNING, "Server returned %s status %i %s",
1256                 scope, code, buf);
1257 }
1258
1259
1260 static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
1261                 const uint16_t code, const void *status_msg, const int len,
1262                 int *ret)
1263 {
1264         dhcpv6_log_status_code(code, "message", status_msg, len);
1265
1266         switch (code) {
1267         case DHCPV6_UnspecFail:
1268                 // Generic failure
1269                 *ret = 0;
1270                 break;
1271
1272         case DHCPV6_UseMulticast:
1273                 // TODO handle multicast status code
1274                 break;
1275
1276         case DHCPV6_NoAddrsAvail:
1277         case DHCPV6_NoPrefixAvail:
1278                 if (orig == DHCPV6_MSG_REQUEST)
1279                         *ret = 0; // Failure
1280                 break;
1281
1282         default:
1283                 break;
1284         }
1285 }
1286
1287
1288 static void dhcpv6_handle_ia_status_code(const enum dhcpv6_msg orig,
1289                 const struct dhcpv6_ia_hdr *ia_hdr, const uint16_t code,
1290                 const void *status_msg, const int len,
1291                 bool handled_status_codes[_DHCPV6_Status_Max], int *ret)
1292 {
1293         dhcpv6_log_status_code(code, ia_hdr->type == DHCPV6_OPT_IA_NA ?
1294                 "IA_NA" : "IA_PD", status_msg, len);
1295
1296         switch (code) {
1297         case DHCPV6_NoBinding:
1298                 switch (orig) {
1299                 case DHCPV6_MSG_RENEW:
1300                 case DHCPV6_MSG_REBIND:
1301                         if ((*ret > 0) && !handled_status_codes[code])
1302                                 *ret = dhcpv6_request(DHCPV6_MSG_REQUEST);
1303                         break;
1304
1305                 default:
1306                         break;
1307                 }
1308                 break;
1309
1310         case DHCPV6_NoAddrsAvail:
1311         case DHCPV6_NoPrefixAvail:
1312                 switch (orig) {
1313                 case DHCPV6_MSG_REQUEST:
1314                         if (*ret != 0)
1315                                 *ret = 0;
1316                         break;
1317                 default:
1318                         break;
1319                 }
1320                 break;
1321
1322         case DHCPV6_NotOnLink:
1323                 // TODO handle not onlink in case of confirm
1324                 break;
1325
1326         default:
1327                 break;
1328         }
1329 }
1330
1331 static void dhcpv6_add_server_cand(const struct dhcpv6_server_cand *cand)
1332 {
1333         size_t cand_len, i;
1334         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1335
1336         // Remove identical duid server candidate
1337         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1338                 if (cand->duid_len == c[i].duid_len &&
1339                                 !memcmp(cand->duid, c[i].duid, cand->duid_len)) {
1340                         free(c[i].ia_na);
1341                         free(c[i].ia_pd);
1342                         odhcp6c_remove_state(STATE_SERVER_CAND, i * sizeof(*c), sizeof(*c));
1343                         break;
1344                 }
1345         }
1346
1347         for (i = 0, c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1348                 i < cand_len / sizeof(*c); ++i) {
1349                 if (c[i].preference < cand->preference)
1350                         break;
1351         }
1352
1353         odhcp6c_insert_state(STATE_SERVER_CAND, i * sizeof(*c), cand, sizeof(*cand));
1354 }
1355
1356 static void dhcpv6_clear_all_server_cand(void)
1357 {
1358         size_t cand_len, i;
1359         struct dhcpv6_server_cand *c = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1360
1361         // Server candidates need deep delete for IA_NA/IA_PD
1362         for (i = 0; i < cand_len / sizeof(*c); ++i) {
1363                 free(c[i].ia_na);
1364                 free(c[i].ia_pd);
1365         }
1366         odhcp6c_clear_state(STATE_SERVER_CAND);
1367 }
1368
1369 int dhcpv6_promote_server_cand(void)
1370 {
1371         size_t cand_len;
1372         struct dhcpv6_server_cand *cand = odhcp6c_get_state(STATE_SERVER_CAND, &cand_len);
1373         uint16_t hdr[2];
1374         int ret = (na_mode == IA_MODE_NONE && pd_mode == IA_MODE_NONE) ?
1375                         DHCPV6_STATELESS : DHCPV6_STATEFUL;
1376
1377         // Clear lingering candidate state info
1378         odhcp6c_clear_state(STATE_SERVER_ID);
1379         odhcp6c_clear_state(STATE_IA_NA);
1380         odhcp6c_clear_state(STATE_IA_PD);
1381
1382         if (!cand_len)
1383                 return -1;
1384
1385         if (cand->has_noaddravail && na_mode == IA_MODE_TRY) {
1386                 na_mode = IA_MODE_NONE;
1387
1388                 dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1389                 dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1390
1391                 return dhcpv6_request(DHCPV6_MSG_SOLICIT);
1392         }
1393
1394         hdr[0] = htons(DHCPV6_OPT_SERVERID);
1395         hdr[1] = htons(cand->duid_len);
1396         odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
1397         odhcp6c_add_state(STATE_SERVER_ID, cand->duid, cand->duid_len);
1398         accept_reconfig = cand->wants_reconfigure;
1399         if (cand->ia_na_len) {
1400                 odhcp6c_add_state(STATE_IA_NA, cand->ia_na, cand->ia_na_len);
1401                 free(cand->ia_na);
1402                 if (na_mode != IA_MODE_NONE)
1403                         ret = DHCPV6_STATEFUL;
1404         }
1405         if (cand->ia_pd_len) {
1406                 odhcp6c_add_state(STATE_IA_PD, cand->ia_pd, cand->ia_pd_len);
1407                 free(cand->ia_pd);
1408                 if (request_prefix)
1409                         ret = DHCPV6_STATEFUL;
1410         }
1411
1412         dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = cand->sol_max_rt;
1413         dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = cand->inf_max_rt;
1414
1415         odhcp6c_remove_state(STATE_SERVER_CAND, 0, sizeof(*cand));
1416
1417         return ret;
1418 }